0001627475-21-000015 | 10-K | XBRL Viewer

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Cover Page - USD ($)	12 Months Ended
Cover Page - USD ($)	Dec. 31, 2020	Jan. 31, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-38678
Entity Registrant Name	UPWORK INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-4337682
Entity Address, Address Line One	2625 Augustine Drive, Suite 601
Entity Address, City or Town	Santa Clara,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95054
City Area Code	650
Local Phone Number	316-7500
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	UPWK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Public Float			$ 1,532,720,862
Entity Common Stock, Shares Outstanding		124,962,279
Entity Central Index Key	0001627475
Current Fiscal Year End Date	--12-31
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for its 2021 Annual Meeting of Stockholders, or Proxy Statement, to be filed within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K, are incorporated by reference in Part III. Except with respect to information specifically incorporated by reference in this Annual Report, the Proxy Statement shall not be deemed to be filed as part hereof.

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 94,081	$ 48,392
Marketable securities	75,570	85,481
Funds held in escrow, including funds in transit	135,042	108,721
Trade and client receivables – net of allowance of $1,661 and $2,215 as of December 31, 2020 and 2019, respectively	47,018	30,156
Prepaid expenses and other current assets	9,090	7,885
Total current assets	360,801	280,635
Property and equipment, net	28,139	21,454
Goodwill	118,219	118,219
Intangible assets, net	667	3,335
Operating lease asset	19,729	21,908
Other assets, noncurrent	1,672	829
Total assets	529,227	446,380
Current liabilities
Accounts payable	6,455	652
Escrow funds payable	135,042	108,721
Debt, current	7,581	7,584
Accrued expenses and other current liabilities	32,868	18,342
Deferred revenue	16,801	13,799
Total current liabilities	198,747	149,098
Debt, noncurrent	3,142	10,699
Operating lease liability, noncurrent	20,506	21,186
Other liabilities, noncurrent	7,522	5,973
Total liabilities	229,917	186,956
Commitments and contingencies (Note 6)
Stockholders’ equity
Common stock, $0.0001 par value; 490,000,000 shares authorized as of December 31, 2020 and 2019; 124,795,222 and 113,604,398 shares issued and outstanding as of December 31, 2020 and 2019, respectively	12	11
Additional paid-in capital	494,122	431,370
Accumulated deficit	(194,824)	(171,957)
Total stockholders’ equity	299,310	259,424
Total liabilities and stockholders’ equity	$ 529,227	$ 446,380

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,661	$ 2,215
Common stock, shares authorized (in shares)	490,000,000	490,000,000
Common stock, shares issued (in shares)	124,795,222	113,604,398
Common stock, shares outstanding (in shares)	124,795,222	113,604,398
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 373,628	$ 300,562	$ 253,354
Cost of revenue	104,267	88,144	81,458
Gross profit	269,361	212,418	171,896
Operating expenses
Research and development	83,471	64,027	55,488
Sales and marketing	133,225	95,891	72,963
General and administrative	71,518	67,327	49,336
Provision for transaction losses	3,555	3,905	5,821
Total operating expenses	291,769	231,150	183,608
Loss from operations	(22,408)	(18,732)	(11,712)
Interest expense	778	1,306	2,038
Other (income) expense, net	(469)	(3,407)	6,142
Total loss before income taxes	(22,717)	(16,631)	(19,892)
Income tax provision	(150)	(28)	(15)
Net loss	$ (22,867)	$ (16,659)	$ (19,907)
Net loss per share basic and diluted (in dollars per share)	$ (0.19)	$ (0.15)	$ (0.38)
Weighted-average shares used to compute net loss per share, basic and diluted	118,698,567	109,814,604	52,327,518

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment
Redeemable convertible preferred stock, beginning balance (in shares) at Dec. 31, 2017			61,279,079
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2017			$ 166,486
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock in connection with the initial public offering (in shares)			(61,279,079)
Conversion of redeemable convertible preferred stock in connection with the initial public offering	$ (166,486)		$ (166,486)
Redeemable convertible preferred stock, ending balance (in shares) at Dec. 31, 2018			0
Redeemable convertible preferred stock, ending balance at Dec. 31, 2018		$ (11,799)	$ 0				$ (11,799)
Beginning balance (in shares) at Dec. 31, 2017				33,740,323
Beginning balance at Dec. 31, 2017	(31,367)			$ 3	$ 92,222	$ (123,592)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				3,567,917
Issuance of common stock upon exercise of stock options and common stock warrants	8,160			$ 1	8,159
Stock-based compensation expense	10,361				10,361
Issuance of common stock in connection with the initial public offering, net of discounts and commissions (in shares)				7,840,908
Issuance of common stock in connection with the initial public offering, net of discounts and commissions	109,381			$ 1	109,380
Costs related to the initial public offering	(6,282)				(6,282)
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	7,160				7,160
Conversion of redeemable convertible preferred stock in connection with the initial public offering (in shares)				61,279,079
Conversion of redeemable convertible preferred stock in connection with the initial public offering	166,486			$ 6	166,480
Issuance of common stock for settlement of RSUs (in shares)				38,742
Shares withheld related to net share settlement of RSUs (in shares)				(12,648)
Shares withheld related to net share settlement of RSUs	(247)				(247)
Net loss	(19,907)					(19,907)
Ending balance at Dec. 31, 2018	243,745			$ 11	387,233	(143,499)
Ending balance (in shares) at Dec. 31, 2018				106,454,321
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock in connection with the initial public offering	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				6,429,471
Issuance of common stock upon exercise of stock options and common stock warrants	18,155				18,155
Stock-based compensation expense	18,616				18,616
Tides Foundation common stock warrant expense and other	975				975
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	0
Issuance of common stock for settlement of RSUs (in shares)				163,943
Issuance of common stock in connection with employee stock purchase plan (in shares)				556,663
Issuance of common stock in connection with employee stock purchase plan	6,391				6,391
Net loss	(16,659)					(16,659)
Ending balance at Dec. 31, 2019	259,424			$ 11	431,370	(171,957)
Ending balance (in shares) at Dec. 31, 2019				113,604,398
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock in connection with the initial public offering	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	9,065,976			9,115,947
Issuance of common stock upon exercise of stock options and common stock warrants	$ 31,028				31,027
Stock-based compensation expense	25,677				25,677
Tides Foundation common stock warrant expense and other	1,135				1,135
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	0
Issuance of common stock for settlement of RSUs (in shares)				1,590,225
Issuance of common stock in connection with employee stock purchase plan (in shares)				484,652
Issuance of common stock in connection with employee stock purchase plan	4,913				4,913
Net loss	(22,867)					(22,867)
Ending balance at Dec. 31, 2020	$ 299,310			$ 12	$ 494,122	$ (194,824)
Ending balance (in shares) at Dec. 31, 2020				124,795,222

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (22,867)	$ (16,659)	$ (19,907)
Adjustments to reconcile net loss to net cash provided by operating activities:
Provision for transaction losses	2,919	3,118	5,110
Depreciation and amortization	10,172	6,661	4,949
Amortization of debt issuance costs	61	52	77
Amortization of discount on purchases of marketable securities	(320)	(1,158)	0
Change in fair value of redeemable convertible preferred stock warrant liability	0	0	6,056
Amortization of operating lease asset	3,860	3,945
Tides Foundation common stock warrant expense	750	711	226
Stock-based compensation expense	25,508	18,798	10,361
Loss on disposal of fixed assets	44	14	91
Changes in operating assets and liabilities:
Trade and client receivables	(20,000)	(10,918)	3,506
Prepaid expenses and other assets	(1,198)	(2,069)	(1,292)
Operating lease liability	(1,851)	(1,453)
Accounts payable	5,822	(1,457)	1,609
Accrued expenses and other liabilities	15,438	(2,957)	2,849
Deferred revenue	4,027	4,430	109
Net cash provided by operating activities	22,365	1,058	13,744
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(107,281)	(168,786)	0
Proceeds from maturities of marketable securities	117,500	84,500	0
Purchases of property and equipment	(6,320)	(10,752)	(3,002)
Internal-use software and platform development costs	(8,045)	(5,886)	(3,839)
Net cash used in investing activities	(4,146)	(100,924)	(6,841)
CASH FLOWS FROM FINANCING ACTIVITIES:
Changes in escrow funds payable	26,321	10,535	10,991
Proceeds from exercises of stock options and common stock warrant	31,028	18,155	8,160
Taxes paid related to net share settlement of restricted stock units	0	0	(247)
Proceeds from borrowings on debt	18,000	50,000	15,000
Repayment of debt	(25,621)	(55,679)	(25,000)
Proceeds from employee stock purchase plan	4,913	6,391	0
Proceeds from the initial public offering, net of discounts and commissions	0	0	109,381
Payments of costs related to the initial public offering	0	0	(6,220)
Net cash provided by financing activities	54,641	29,402	112,065
NET CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	72,860	(70,464)	118,968
Cash, cash equivalents, and restricted cash—beginning of year	159,603	230,067	111,099
Cash, cash equivalents, and restricted cash—end of year	232,463	159,603	230,067
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	764	1,291	1,976
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Property and equipment purchased but not yet paid	37	161	2,815
Internal-use software and platform development costs incurred but not yet paid	286	684	130
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	0	0	7,160
Conversion of redeemable convertible preferred stock in connection with the initial public offering	$ 0	$ 0	$ 166,486

Organization and Description of Business	12 Months Ended
Organization and Description of Business	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Upwork Inc., which is referred to as the Company or Upwork, operates a work marketplace that connects businesses, which are referred to as clients, with independent talent. Independent talent on the Company’s work marketplace, which are referred to as freelancers, and, together with clients, as users, include independent professionals and agencies of varying sizes and are an increasingly sought-after, critical, and expanding segment of the global workforce. The Company was originally incorporated in the state of Delaware in December 2013 prior to and in connection with the combination, which is referred to as the Elance-oDesk Combination, of Elance, Inc., which is referred to as Elance, and oDesk Corporation, which is referred to as oDesk. The Company changed its name to Elance-oDesk, Inc. shortly before the Elance-oDesk Combination in March 2014, and later to Upwork Inc. In 2015, the Company relaunched as Upwork and commenced consolidation of its two operating platforms. In 2016, following completion of the platform consolidation, the Company began operating under a single work marketplace. The Company is currently headquartered in Santa Clara, California. Unless otherwise expressly stated or the context otherwise requires, the terms “Upwork” and the “Company” in these notes to the consolidated financial statements refer to Upwork and its wholly-owned subsidiaries. Initial Public Offering In October 2018, the Company completed its initial public offering, which is referred to as the IPO, in which the Company issued and sold an aggregate of 7,840,908 of the Company’s common stock, including 1,022,727 shares pursuant to the exercise of the underwriters’ option to purchase additional shares. The shares were sold to the underwriters at the IPO price of $15.00 per share less an underwriting discount of $1.05 per share. The Company received aggregate net proceeds of $109.4 million from the IPO after deducting underwriting discounts and commissions but before deducting offering expenses payable by the Company.

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States, which is referred to as U.S. GAAP, and include the accounts of Upwork Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

Results and disclosure requirements for reporting periods beginning after January 1, 2019 are presented under Topics 606 and 842, while prior period amounts have not been adjusted and continue to be reported under Topics 605 and 840.

Use of Estimates

The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates, judgments, and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the periods presented. Such estimates include, but are not limited to: the useful lives of assets; assessment of the recoverability of long-lived assets; goodwill impairment; standalone selling price of material rights and the period of time over which to defer and recognize the consideration allocated to the material rights; allowance for doubtful accounts; liabilities relating to transaction losses; the valuation of warrants; stock-based compensation; and accounting for income taxes. Management bases its estimates on historical experience and on various other assumptions that management believes to be reasonable under the circumstances. The Company evaluates its estimates, assumptions, and judgments on an ongoing basis using historical experience and other factors and revises them when facts and circumstances dictate.

Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions.

Cash and Cash Equivalents

The Company classifies as cash and cash equivalents its cash held in checking and interest-bearing accounts and investments in money market funds and commercial paper with maturities of 90 days or less from the date of purchase.

Restricted Cash

As of December 31, 2020 and 2019, the Company maintained restricted cash of $3.3 million and $2.5 million, respectively, related to cash reserve requirements under the escrow laws and regulations of the California Department of Financial Protection and Innovation and collateral for letters of credit issued in conjunction with operating leases. Short-term restricted cash included in prepaid expenses and other current assets was $2.3 million and $1.7 million as of December 31, 2020 and 2019, respectively, and long-term restricted cash included in other assets, noncurrent was $1.0 million and $0.8 million as of December 31, 2020 and 2019, respectively.

Funds Held in Escrow, Including Funds in Transit

The Company maintains its users’ funds held in escrow in demand or checking accounts at U.S. financial institutions, as well as three California licensed money transmitters. The balance in these accounts was in excess of federally insured limits as of December 31, 2020 and 2019. Users’ funds held in escrow are denominated exclusively in U.S. dollars.

The Company is an internet escrow agent and is therefore required to hold its users’ escrowed funds and escrow funds in transit in trust as an asset and record a corresponding liability for escrow funds payable on its consolidated balance sheets. For this reason, funds held in escrow, including funds in transit, are restricted cash. Escrow funds in transit arise due to the time it takes to clear transactions through external payment networks. When clients fund their escrow account using credit cards, there is a clearing period before the cash is received and settled. Accordingly, the funds are treated as escrow funds in transit until the transaction is settled to the escrow trust bank account or, in the case of international credit card settlements, to the Company’s bank accounts. Escrow regulations require the Company to fund the trust with its own operating cash if there is ever a shortage due to the timing of cash receipts from clients for completed hourly billings. As of December 31, 2020 and 2019, the Company recorded $135.0 million and $108.7 million, respectively, as funds held in escrow, including funds in transit.

The below table reconciles cash, cash equivalents, and restricted cash as reported in the consolidated balance sheets to the total of the same amounts shown in the consolidated statements of cash flows for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Cash and cash equivalents	$	94,081	$	48,392	$	129,128
Restricted cash	3,340		2,490		2,753
Funds held in escrow, including funds in transit	135,042		108,721		98,186
Total cash, cash equivalents, and restricted cash as shown in the consolidated statement of cash flows	$	232,463	$	159,603	$	230,067

Marketable Securities

The Company’s marketable securities consist of commercial paper, treasury bills, and U.S. government securities, all of which have contractual maturities within 24 months from the date of purchase. The marketable securities are available for current operations and are classified as available-for-sale. These marketable securities are carried at estimated fair value with unrealized gains and losses, net of taxes, included within the stockholders’ equity section of the Company’s consolidated balance sheet.

The Company periodically assesses its portfolio of debt investments for impairment. For debt securities in an unrealized loss position, this assessment first takes into account the Company’s intent to sell, or whether it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis. If either of these criteria are met, the debt security’s amortized cost basis is written down to fair value through other (income) expense, net. For debt securities in an unrealized loss position that do not meet the aforementioned criteria, the Company assesses whether the decline in fair value below the amortized cost basis resulted from a credit loss or other factors. In making this assessment, the Company considers factors such as the extent to which fair value is less than the amortized cost basis, the financial condition of the issuer, any changes to the rating of the security by a rating agency, and any adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss may exist, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses will be recorded through other (income) expense, net, limited by the amount that the fair value is less than the amortized cost basis. Any additional impairment not recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are reflected as provision for (or reversal of) credit loss expense. Losses are charged against the allowance when management believes the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell are met. These changes are recorded in other (income) expense, net. The Company determines realized gains or losses from the sale of marketable securities on a specific identification method and records such gains or losses as other (income) expense, net within the Company’s consolidated statements of operations.

For the year ended December 31, 2020, the gross unrealized gains and losses on the Company’s marketable securities were immaterial. The Company did not record any impairment charges with respect to its marketable securities during the years ended December 31, 2020, 2019, and 2018.

Escrow Funds Payable

Escrow funds payable represent user funds that are held in escrow by the Company on behalf of both freelancers and clients. Escrow funds payable to freelancers are comprised primarily of funds available to be withdrawn by freelancers for work performed and paid by clients. Escrow funds payable to clients primarily represent deposits received from certain clients to set up an account or to apply toward future payments to freelancers upon completion of the project defined and agreed between the client and the freelancer.

Concentration of Risk

Financial instruments that subject the Company to concentration of risk consist primarily of cash, restricted cash, funds held in escrow, including funds in transit, and trade and client receivables. The Company maintains its cash balances with large, high-credit quality financial institutions and other payment companies. At times, such deposits may be in excess of federally insured limits. The Company has not experienced any losses on its deposits. Credit risk on trade receivables is limited as a result of the large size of the Company’s client base as well as a large portion of payments made using pre-authorized credit cards. The Company performs ongoing credit evaluations of its clients and maintains allowances for potential credit losses. For any receivables that are deemed not collectible, losses are recorded when probable and estimable. These losses, when incurred, have been within the range of the Company’s expectations.

Three clients each accounted for more than 10% of trade and client receivables as of December 31, 2020. Two clients each accounted for more than 10% of trade and client receivables as of December 31, 2019. For the year ended December 31, 2020, the Company did not have any clients that accounted for more than 10% of total revenue. For the years ended December 31, 2019 and 2018, the Company generated $32.0 million and $29.5 million, respectively, in revenue from one of these clients, which accounted for more than 10% of revenue during the years ended December 31, 2019 and 2018.

The Company is dependent upon third parties, such as Amazon Web Services, in order to meet the uptime and performance needs of its users.

Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, restricted cash, funds held in escrow, including funds in transit, marketable securities, trade and client receivables, prepaid and other current assets, escrow funds payable, debt, and the redeemable convertible preferred stock warrant liability. Prior to the IPO, the redeemable convertible preferred stock warrant liability was remeasured at the end of every period and was carried at fair value. Upon the IPO, the redeemable convertible preferred stock warrant was converted to a common stock warrant and is no longer remeasured.

The Company believes that the carrying values of the remaining financial instruments approximate their fair values.

Trade and Client Receivables and Related Allowance for Doubtful Accounts

Trade and client receivables are primarily comprised of receivables from the Company’s managed services offering and amounts receivable from clients for completed work, including amounts in transit. It also includes unbilled amounts due from clients. Trade and client receivables are recorded and stated at realizable value, net of an allowance for doubtful accounts. Credit is extended generally without collateral to the Company’s managed services client and marketplace clients with Upwork Enterprise offerings based on an initial and ongoing evaluation of their financial condition and other factors. In aggregate, gross trade receivables were $15.9 million and $10.3 million and gross client receivables were $32.8 million and $22.1 million as of December 31, 2020 and 2019, respectively.

The allowance for doubtful accounts is the Company’s estimate of the probable credit losses on accounts receivable. The Company periodically assesses the collectability of the accounts and determines the allowance recognized by taking into consideration the aging of its receivable balances, historical write-off experience, probability of collection, and other relevant data. Trade and client receivables are written off against the allowance when management determines a balance is uncollectible and no longer actively pursues collection of the receivable.

The following table presents the changes in the allowance for doubtful accounts as of December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Allowance for doubtful accounts, beginning balance	$	2,215	$	2,832	$	1,577
Provision for doubtful accounts	3,143		3,193		4,940
Amounts written off	(3,697)		(3,810)		(3,685)
Allowance for doubtful accounts, ending balance	$	1,661	$	2,215	$	2,832

Derivative Instruments

The Company uses derivative financial instruments not designated as hedges, such as foreign currency forward contracts, to minimize the short-term impact of foreign currency exchange rate fluctuations on certain foreign currency denominated assets and liabilities, as well as certain foreign currency denominated expenses, hedging the gains or losses generated by the re-measurement of significant foreign currency denominated monetary assets and liabilities. The Company does not enter into derivative instruments for speculative or trading purposes and these instruments generally have maturities within 12 months.

The foreign currency forward contracts are recorded at fair value and, when in gain positions, are reported within prepaid expenses and other current assets. When in loss positions, the foreign currency forward contracts are recorded within accrued expenses and other current liabilities in the consolidated balance sheets. Gains or losses from changes in the fair value of these foreign currency forward contracts not designated as hedging instruments are recorded in other (income) expense, net to offset the changes in the fair value of the underlying assets or liabilities being hedged.

The notional amounts associated with the Company’s foreign currency forward contracts at December 31, 2020 and 2019 were $7.6 million and $5.4 million, respectively, none of which were designated as cash flow hedges. The carrying values of the foreign currency forward contracts approximated their fair values due to their relatively short settlement durations. The fair values of the Company’s outstanding foreign currency forward contracts not designated as hedging instruments as of December 31, 2020 and 2019 were not material. Losses on foreign currency forward contracts not designated as hedging instruments were $0.6 million for the year ended December 31, 2020. Gains on foreign currency forward contracts not designated as hedging instruments were $0.9 million for the year ended December 31, 2019. Losses on foreign currency forward contracts not designated as hedging instruments were $0.4 million for the year ended December 31, 2018.

Property and Equipment

Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets, which are generally two to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of the remaining lease term or their estimated useful lives. Repair and maintenance costs are charged to expense as incurred.

Internal-Use Software and Platform Development Costs

The Company’s policy is to capitalize certain costs to develop its internal-use software and platform when (i) preliminary project planning is completed, (ii) the Company has committed project resourcing, and (iii) it is probable that the project will be completed and the software will be used as intended. Costs incurred for enhancements that are expected to result in additional significant functionality are also capitalized. Such costs are generally amortized on a straight-line basis over their estimated useful lives determined on a project-by-project basis, which historically has ranged between two to three years, beginning when the asset is ready for its intended use. Costs incurred prior to meeting these criteria, together with costs incurred for training and maintenance, are expensed as incurred. Amortization of capitalized internal-use software and platform development costs is allocated to functional expense categories based on headcount and the nature and intended use of the project.

Segment Information

The Company has one reportable segment. The Company’s chief operating decision maker is its President and Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance.

Goodwill, Acquired Intangible Assets, and Other Long-Lived Assets

Goodwill represents the excess of the aggregate fair value of the consideration transferred over the fair value of the net tangible and identifiable intangible assets acquired in the Elance-oDesk Combination. Goodwill is not amortized, but rather is assessed for impairment at least annually, or more frequently if events and changes in circumstances indicate that its carrying amount may not be recoverable. The Company performs its annual impairment assessment during the fourth quarter of each calendar

year based on a single reporting unit structure by comparing the carrying value of the reporting unit to its fair value. An impairment would occur if the carrying amount of a reporting unit exceeded the fair value of that reporting unit. There has been no impairment of goodwill for any of the periods presented.

The Company’s long-lived assets consist of property and equipment and acquired identifiable, finite-lived intangible assets, namely developed technology, user relationships, trade names, and domain names. The finite-lived intangible assets are carried at cost, less accumulated amortization. The Company amortizes the finite-lived intangible assets over their estimated useful lives ranging from two to seven years based on the pattern in which the economic benefits of the intangible assets are consumed, or the straight-line method when the pattern cannot be reliably determined. The Company periodically reviews the remaining estimated useful lives of its long-lived tangible and amortizable intangible assets. If the estimated useful life assumption for any asset is changed, the remaining unamortized balance would be depreciated or amortized over the revised estimated useful life, on a prospective basis. Intangible amortization expense related to developed technology and trade names is recorded as cost of revenue. Intangible amortization expense related to user relationships and domain names is included in operating expenses.

The Company evaluates the recoverability of its long-lived assets, including finite-lived intangible assets, for possible impairment whenever events or circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of these assets is measured by comparing the carrying amounts to the future undiscounted cash flows the assets are expected to generate. If it is determined that the asset group is not recoverable, an impairment loss is recorded in the amount by which the carrying amount of the asset group exceeds the aggregate future undiscounted cash flows. When an impairment loss is recognized, the carrying amount of such assets is reduced to fair value.

For 2020, the Company conducted its goodwill impairment testing by performing the first step of the two-step impairment model. The fair value was determined by the Company using quoted market prices of the Company’s common stock. The Company determined that the fair value of its reporting unit exceeded the carrying value, and, as such, the Company concluded that there was no impairment of goodwill at the impairment testing date.

There was no impairment of long-lived assets in any of the periods presented.

Deferred Offering Costs

Deferred offering costs, consisting of legal, accounting, and filing fees directly relating to the Company’s IPO, were capitalized and offset against the IPO proceeds upon the completion of the offering. Upon completion of the Company’s IPO, approximately $6.3 million of deferred offering costs were offset against the IPO proceeds in additional paid-in capital.

Revenue Recognition

The Company primarily generates revenue from clients from its marketplace and managed service offerings and from freelancers from its marketplace. The Company accounts for revenue in accordance with Financial Accounting Standards Board, which is referred to as FASB, Accounting Standards Update, which is referred to as ASU, No. 2014-09, Revenue from Contracts with Customers (Topic 606), which the Company adopted on December 31, 2019 effective as of January 1, 2019 using the modified retrospective method. Revenue is recognized upon transfer of control of promised services to users in an amount that reflects the consideration the Company expects to receive in exchange for those services.

In the ordinary course of business, the Company makes payments to users when those users provide services in their capacity as vendors. These payments are for distinct services and are at fair value. These transactions are primarily with certain financial institutions that the Company uses as payment processors on the work marketplace. The Company accounts for the consideration payable to these users in their capacity as vendors as a purchase of services from a vendor and records such payments in either cost of revenue or sales and marketing within the consolidated statements of operations.

Marketplace

The Company’s marketplace revenue is derived from Upwork Basic, Plus, and Enterprise and other premium offerings.

Upwork Basic and Plus

The Company earns fees from freelancers under the Upwork Basic and Plus offerings, which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services (including, but not limited to, communication, invoicing, reporting, dispute resolution, and payment services) is substantially the same and the freelancer simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Basic and Plus offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. The Company’s Upwork Basic and Plus arrangements may include fixed and variable consideration, or a combination of the two, comprised of the following:

Service fees. Freelancers are provided access to the Upwork work marketplace to market their businesses, send proposals to and communicate with prospective clients, and, if engaged by a client, to perform specified services agreed between freelancers and clients, which are referred to as freelancer services. Freelancers charge clients on an hourly or a milestone basis for services rendered to clients through the Upwork work marketplace, which are referred to as freelancer billings; billings charged on an hourly basis are variable consideration; and billings on a milestone basis represent fixed consideration. The Company charges freelancers a service fee as a percentage of freelancer billings using a tiered service fee model based on cumulative lifetime billings by the freelancer to each client. The arrangements subject to tiered service fees also include contract renewal options that represent a material right. The Company takes no responsibility for the freelancer services, and therefore, does not control the freelancer services. Additionally, freelancers and clients negotiate and agree upon the scope and the price for freelancer services directly with each other, and the Company is not a party to those agreements. Accordingly, for these tiered service fee arrangements, the Company presents revenue on a net basis, as an agent. The Company recognizes the service fee as services are rendered for each distinct time increment in the series.

Withdrawal fees. The Company charges withdrawal fees to freelancers when the freelancers withdraw their escrow funds held by the Company. A withdrawal fee is charged for each withdrawal transaction, which represents variable consideration. The Company presents revenue from withdrawal fees on a gross basis as a principal and not net of the third-party payment processing costs incurred because the Company controls the payment processing services prior to providing to the Company's freelancers. The Company recognizes the withdrawal fees when transactions are processed for each distinct time increment in the series.

Membership fees. The Company charges membership fees to freelancers. These fees are fixed consideration and are charged monthly. The Company recognizes the revenue over the period of the membership consistent with the common measure of progress for the entire performance obligation.

Connects fees. The Company charges fees to freelancers for the purchase of Connects, which are virtual tokens that are required for freelancers to bid on projects on the Company’s work marketplace. These fees represent variable consideration, and the Company recognizes revenue as Connects are used in each distinct time increment in the series.

The Company earns fees from clients under the Upwork Basic and Plus offerings, which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services is substantially the same and the client simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Basic and Plus offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. The Company’s Upwork Basic and Plus arrangements may include fixed and variable consideration, or a combination of the two, comprised of the following:

Client payment processing and administration fees. The Company charges clients for payment processing services at the time the client is charged for the amounts due from the client. This fee is charged on a per-transaction basis and is variable consideration. Per-transaction payment processing fees are recognized when the client is charged for the amount due and fees charged on a monthly basis are recognized over the month that payment processing services are provided. For client payment processing fees, the Company presents revenue on a gross basis as a principal and not net of the third-party payment processing costs incurred because the Company controls the payment processing and administration services prior to providing to the Company’s clients. The Company recognizes the revenue when a payment from a client is processed in each distinct time increment in the series.

Foreign currency exchange fees. The Company charges clients a fixed mark-up above foreign currency exchange rates that are charged to the Company when the Company collects amounts denominated in foreign currency. Foreign currency exchange fees are variable consideration and recognized as they are earned for each transaction processed in each distinct time increment in the series.

Membership fees. The Company charges membership fees to clients. These fees are charged monthly, are fixed consideration, and are recognized over the period of the membership, which is generally monthly consistent with the common measure of progress for the entire performance obligation.

Upwork Payroll service fees. The Company charges clients using the Upwork Payroll offering when their freelancers are classified as employees for engagements on the Upwork work marketplace. The client enters into an Upwork Payroll agreement with the Company, and Upwork separately contracts with unrelated third-party staffing providers that provide employment services to such clients. In such arrangements, freelancers providing freelancer services to clients become employees of third-party staffing providers. In arrangements where clients enter into Upwork Payroll agreements, the Company charges Upwork Payroll service fees to clients and does not charge service fees to the freelancers who are employees of the third-party staffing providers. Such service fees are variable consideration and charged as a fixed percentage of the total freelancer billings. Under an Upwork Payroll agreement, the Company provides the client access to

the Upwork work marketplace to procure and manage freelancer services, as well as access to employment services provided by the third-party staffing providers. The Company presents Upwork Payroll service fees revenue on a net basis as an agent of the client for providing access to employment services provided by the third-party staffing provider. The Company does not control these employment services performed by the third-party on behalf of the client or for the services performed by the freelancers that are employed by the third-party staffing provider. Therefore, the Company is not considered the principal for these services. The Company recognizes the Upwork payroll service fee as revenue as the services are provided for each distinct time increment in the series.

Upwork Enterprise and Other Premium Offerings

The Company earns fees from freelancers under Upwork Enterprise and other premium offerings, which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services is substantially the same and the freelancer simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Enterprise and other premium offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. These arrangements include variable consideration as follows:

Service fees. The Company provides freelancers access to the Upwork work marketplace to perform freelancer services for clients. The Company charges freelancers a service fee as a percentage of freelancer billings. The Company earns service fees based on a fixed percentage of freelancer billings. For service fees charged to freelancers, the Company presents revenue on a net basis, as an agent, for providing access to the Upwork work marketplace as it does not control the freelancer services provided to clients, and therefore the Company is not considered the principal for the freelancer services. Additionally, freelancers and clients negotiate and agree upon the scope and the price for freelancer services directly with each other, and the Company is not a party to their agreement. The Company recognizes the service fee as services are rendered for each distinct time increment in the series.

The Company earns fees from clients under Upwork Enterprise and other premium offerings, each of which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services is substantially the same and the client simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Enterprise and other premium offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. These arrangements may include fixed and variable consideration, or a combination of the two, comprised of the following:

Client service fees. The Company offers clients access to the Company’s work marketplace to source freelancers in exchange for a client service fee calculated as a percentage of freelancer billings; these fees represent variable consideration. The Company recognizes the service fee as services are rendered for each distinct time increment in the series.

Enterprise compliance service fees. The Company charges fees to its enterprise compliance service clients that engage the Company to provide services to determine whether a freelancer should be classified as an employee or an independent contractor based on the scope of freelancer services agreed between the client and freelancer and other factors. The Company charges enterprise compliance service fees as a percentage of freelancer billings; these fees represent variable consideration. The Company recognizes the compliance service fee as services are rendered for each distinct time increment in the series.

Subscription fees. The Company charges monthly or annual subscription fees to clients for subscription services. These subscription fees are fixed consideration and are recognized over the period of the subscription consistent with the common measure of progress for the entire performance obligation.

Upwork Payroll service fees. Upwork Payroll service fees are recognized on the same basis as described under the Upwork Basic and Plus offerings and are variable consideration.

Revenue sharing arrangements

Certain of the Company’s offerings include revenue sharing arrangements under which the Company generates a revenue share as a percentage of the fees charged by certain financial institutions to the freelancers for payment withdrawals. These arrangements are considered a single performance obligation comprised of variable consideration and are recognized over time based on transactions processed.

Managed Services

Under a managed services arrangement, the Company is responsible for providing services and engaging freelancers directly or as employees of third-party staffing providers to perform the services for clients on the Company’s behalf. These arrangements are generally time- and materials-based, and are invoiced on a monthly basis. These fees represent variable consideration. The Company controls and directs the services performed on behalf of the freelancers and presents revenue on a gross basis as principal. As each day of providing managed services is substantially the same and the client simultaneously receives and consumes the benefits as services are provided, the Company’s single promise under its managed services is comprised of a series of distinct service periods. For managed services arrangements with clients, the Company allocates the variable amounts to each distinct service period within the series and recognizes revenue as each distinct service period is performed.

Arrangements with Multiple Performance Obligations

Certain of the Company’s contracts with freelancers contain multiple performance obligations in the event the Company determines a material right exists. Specifically, the arrangements with freelancers subject to tiered service fees include contract renewal options that represent a material right. For such arrangements, the Company allocates revenue to each performance obligation based on its relative standalone selling price by applying the portfolio approach practical expedient under Topic 606. Standalone selling prices for offerings subject to tiered service fees are estimated based on observable transactions when these services are sold on a standalone basis. Standalone selling price for a material right is estimated by determining the discount that the freelancer would obtain when exercising the option, adjusted for the likelihood that the option will be exercised. Significant judgment is applied in the application of the portfolio approach practical expedient, which includes estimating the standalone selling price of the material rights and the period of time over which to defer and recognize the consideration allocated to the material rights. Specifically, management applied significant judgment in assessing the appropriateness of the model for the estimates, which include assessing the appropriateness of the methodology and relevant data inputs to (i) estimate the standalone selling price of the material rights, which includes the standalone selling price of the services when sold separately and the likelihood of exercise of the material rights; and (ii) estimate the period of time over which to defer and recognize the consideration allocated to the material rights. The Company utilized historical user transaction data in developing the estimates. The Company recognizes revenue related to the material rights based on the Company’s estimate of when the material rights are exercised and adjusts revenue for changes in estimates in the period of change on a cumulative catch-up basis.

Deferred Revenue

Deferred revenue consists of subscription, membership, and Connects fees collected in advance of performing the service. The Company also recognizes deferred revenue for amounts attributable to unexercised material rights related to arrangements with freelancers that are subject to tiered service fees.

Cost of Revenue

Cost of revenue consists primarily of the cost of payment processing fees, costs of freelancers to deliver services under the Company’s managed services offering, personnel-related costs for the Company’s services and support personnel, third-party hosting fees, and amortization expense associated with acquired intangibles and capitalized internal-use software. The Company defines personnel-related costs as salaries, bonuses, benefits, and stock-based compensation costs for employees, and costs related to other service providers the Company engages to provide internal services to the Company.

Research and Development

Research and development expense primarily consists of personnel-related costs and third-party hosting costs related to development. Research and development costs are expensed as incurred, except to the extent that such costs are associated with internal-use software and platform development that qualify for capitalization.

Advertising Expense

The Company expenses advertising costs as incurred. The Company incurred $51.4 million, $37.4 million, and $23.6 million in advertising expenses during the years ended December 31, 2020, 2019, and 2018, respectively.

Provision for Transaction Losses

Provision for transaction losses consists primarily of losses resulting from fraud on the work marketplace and bad debt expense associated with the Company’s trade and client receivables balance and transaction losses expense related to chargebacks. Provision for these items represent estimates of losses based on the Company’s actual historical incurred losses and other factors.

Redeemable Convertible Preferred Stock Warrant Liability

The Company accounts for freestanding warrants to purchase shares of its redeemable convertible preferred stock as a liability as the underlying shares of convertible preferred stock are contingently redeemable and, therefore, may obligate the Company to transfer assets at some point in the future. The redeemable convertible preferred stock warrants are recorded as other liabilities, noncurrent in the consolidated balance sheets at their estimated fair values and are subject to remeasurement at each balance sheet date. Any change in fair value from remeasurement is recognized as a component of other (income) expense, net in the consolidated statements of operations.

The Company adjusted the liability for changes in fair value through the completion of its IPO in October 2018, at which time the outstanding redeemable convertible preferred stock warrant converted to a common stock warrant and was reclassified to additional paid-in capital.

Stock-Based Compensation

The Company accounts for stock options, restricted stock units, which are referred to as RSUs, and purchase rights granted under the 2018 Employee Stock Purchase Plan, which is referred to as the 2018 ESPP, to employees and directors based on their estimated fair value on the date of grant. The fair value of each stock option and purchase rights granted under the 2018 ESPP is estimated using the Black-Scholes valuation model. The model requires the Company to make a number of assumptions, including the value of the Company’s common stock, expected volatility, expected term, risk-free interest rate, and expected dividends. The Company evaluates the assumptions used to value option awards upon each grant of stock options. The fair value of RSUs awarded to employees is based on the closing price of the Company’s common stock, as reported on The Nasdaq Global Select Market on the date of grant.

The Company generally recognizes stock-based compensation expense for stock options and RSUs on a straight-line basis over the vesting term. Stock-based compensation for purchase rights granted under the 2018 ESPP is recognized over the offering period. The Company accounts for forfeitures as they occur.

Foreign Currency

The functional currency of the Company and its subsidiaries is the U.S. dollar. Transactions with users denominated in currencies other than the U.S. dollar are remeasured at the exchange rate in effect on the date of the transaction. At the end of each reporting period, monetary assets and liabilities are remeasured using exchange rates in effect at the balance sheet date. Foreign currency transaction gains and losses are included in other (income) expense, net in the consolidated statements of operations. The Company recorded net foreign currency transaction losses of $0.6 million for the year ended December 31, 2020, net foreign currency transaction gains of $0.9 million for the year ended December 31, 2019, and net foreign currency transaction losses of $0.4 million for the year ended December 31, 2018.

Comprehensive Loss

For the year ended December 31, 2020, net unrealized losses from the Company’s marketable securities were immaterial. Comprehensive loss approximates net loss for all periods presented. Accordingly, the consolidated statements of comprehensive loss have been omitted from the consolidated financial statements.

Income Taxes

The Company accounts for income taxes in accordance with the liability method. Under the liability method, deferred assets and liabilities are recognized based upon anticipated future tax consequences attributable to differences between financial statement carrying amounts of assets and liabilities and their respective tax bases. The provision for income taxes is comprised of the current tax liability and the change in deferred tax assets and liabilities. The Company establishes a valuation allowance to the extent that it is more likely than not that deferred tax assets will not be recoverable against future taxable income.

Deferred tax assets and liabilities are measured using the enacted tax rates that will be in effect for the years in which those tax assets are expected to be realized or settled. The Company regularly assesses the likelihood that its deferred tax assets will be realized from recoverable income taxes or recovered from future taxable income based on the realization criteria set forth in the relevant authoritative guidance. To the extent that the Company believes any amounts are not more likely than not to be realized, the Company records a valuation allowance to reduce its deferred tax assets. The realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets

have been fully offset by a valuation allowance. If the Company subsequently realizes deferred tax assets that were previously determined to be unrealizable, the respective valuation allowance would be reversed, resulting in an adjustment to earnings in the period such determination is made.

In addition, the calculation of tax liabilities involved dealing with uncertainties in the application of complex tax regulations. The Company recognized potential liabilities based on its estimate of whether, and the extent to which, additional taxes will be due. The Company accounts for uncertain tax positions in accordance with the relevant guidance, which prescribes a recognition threshold and measurement approach for uncertain tax positions taken or expected to be taken in a company’s income tax return, and also provides guidance on recognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition. The guidance utilized a two-step approach for evaluation uncertain tax positions. Step one, Recognition, requires a company to determine if the weight of available evidence indicates a tax position is more likely than not to be sustained upon audit. Step two, Measurement, is based on the largest amount of benefit, which is more likely than not to be realized on ultimate settlement. A liability is reported for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. Any interest and penalties related to unrecognized tax benefits are recorded as income tax expense.

Net Loss per Share

Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss is computed by adjusting net loss to reallocate undistributed earnings based on the potential impact of dilutive securities, including outstanding common stock options, RSUs, warrants to purchase common stock, and common stock issuable in connection with the 2018 ESPP. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share because dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

Recent Accounting Pronouncements Not Yet Adopted

The Company has reviewed all recently issued accounting pronouncements and concluded they were either not applicable or not expected to have a material impact on the Company’s consolidated financial statements.

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU No. 2016–13, Financial Instruments—Credit Losses (Topic 326). This standard changes the methodology for measuring credit losses on financial instruments and the timing of when such losses are recorded. In April 2019, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments. The amendments in this update represent changes to clarify, correct errors in, or improve the Codification. In May 2019, the FASB issued ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326). The amendments in this update provide entities that have certain instruments within the scope of Subtopic 326-20, Financial Instruments—Credit Losses—Measured at Amortized Cost, with an option to irrevocably elect the fair value option in Subtopic 825-10, Financial Instruments—Overall, applied on an instrument-by-instrument basis for eligible instruments, upon adoption of Topic 326. This guidance is effective January 1, 2020 with early adoption permitted. The standard requires a modified retrospective method of adoption. The Company adopted ASU No. 2016-13 and related updates on January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Others (Topic 350): Simplifying the Test for Goodwill Impairment. ASU No. 2017-04 eliminates Step 2 from the goodwill impairment test, which measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. Under ASU No. 2017-04, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of the reporting unit with its carrying amount and recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the loss not exceeding the total amount of goodwill allocated to that reporting unit. The guidance becomes effective for the Company on January 1, 2020 on a prospective basis for its annual or any interim goodwill impairment tests during the 2020 fiscal year. The Company adopted ASU No. 2017-04 on January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement, which modifies the disclosure requirements on fair value measurements. ASU No. 2018-13 is effective for the Company beginning January 1, 2020. The Company adopted ASU No. 2018-13 on January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (“Subtopic 350-40”): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. ASU No. 2018-15 aligns the requirements for capitalizing implementation costs in a cloud computing arrangement

service contract with the requirements for capitalizing implementation costs incurred for an internal-use software license. ASU No. 2018-15 is effective for the Company beginning January 1, 2020. The Company adopted ASU No. 2018-15 on January 1, 2020 using the prospective adoption method. The adoption did not have a material impact on the Company’s consolidated financial statements.

Revenue

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Revenue

Disaggregation of Revenue

See Note 14 for the Company’s revenue disaggregated by type of service and geographic area.

Remaining Performance Obligations

As of December 31, 2020, the Company had approximately $21.0 million of remaining performance obligations. The Company’s remaining performance obligations consist of transaction price that has been allocated to unexercised material rights related to the Company’s arrangements with freelancers subject to tiered service fees, subscriptions, memberships, Connects, and certain incentive payments made to the Company by payment processors. As of December 31, 2020, the Company expects to recognize approximately $16.8 million over the next 12 months, with the remaining balance recognized thereafter.

The Company has applied the practical expedients and exemptions and does not disclose the value of remaining performance obligations for (i) contracts with an original expected length of one year or less; and (ii) contracts for which the variable consideration is allocated entirely to a wholly unsatisfied promise to transfer a distinct service that forms part of a single performance obligation under the series guidance.

Contract Balances

The following table provides information about the balances of the Company’s trade and client receivables, net of allowance and contract liabilities included in deferred revenue and other liabilities, noncurrent as of December 31, 2020 and 2019 (in thousands):


	2020		2019
Trade and client receivables, net of allowance	$	47,018	$	30,156
Contract liabilities
Deferred revenue	16,801		13,799
Deferred revenue (component of other liabilities, noncurrent)	4,177		3,153

During 2020, changes in the contract liabilities balances were a result of normal business activity, deferral of revenue related to arrangements with freelancers subject to tiered service fees and related allocation of transaction price to material rights, and a change in estimate related to the period of time over which to recognize the consideration allocated to the material rights.

Revenue recognized during the year ended December 31, 2020 that was included in deferred revenue as of December 31, 2019 was $13.0 million. Revenue recognized during the year ended December 31, 2019 that was included in deferred revenue as of January 1, 2019 was $10.1 million.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Topic 606
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-Section 50
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-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Section 50
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
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-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

The Company defines fair value as the exchange price that would be received from the sale of an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance describes three levels of inputs that may be used to measure fair value:

•Level I—Observable inputs that reflect unadjusted quoted prices for identical assets or liabilities in active markets;

•Level II—Observable inputs other than Level I prices, such as unadjusted quoted prices for similar assets or liabilities in active markets, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and

•Level III—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. These inputs are based on the Company’s own assumptions used to measure assets and liabilities at fair value and require significant management judgment or estimation.

The categorization of a financial instrument within the fair value hierarchy is based upon the lowest level of input that is significant to its fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the assets or liabilities.

The Company’s financial instruments that are carried at fair value consist of Level I and Level II assets as of December 31, 2020 and 2019. The following tables set forth the fair value of the Company’s financial assets measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands):


	December 31, 2020
	Level I		Level II		Level III		Total

Cash equivalents
Money market funds	$	65,723	$	—	$	—	$	65,723
Commercial paper	—		5,999		—		5,999
Marketable securities
Commercial paper	—		50,965		—		50,965
Treasury Bills	4,499		—		—		4,499
U.S. government securities	20,106		—		—		20,106
Total financial assets	$	90,328	$	56,964	$	—	$	147,292


	December 31, 2019
	Level I		Level II		Level III		Total

Cash equivalents—money market funds	$	35,286	$	—	$	—	$	35,286
Marketable securities
Commercial paper	—		50,794		—		50,794
U.S. government securities	34,687		—		—		34,687
Total financial assets	$	69,973	$	50,794	$	—	$	120,767

As of December 31, 2020 and 2019, the Company had debt obligations outstanding of $10.8 million and $18.3 million, respectively, under the Company’s Loan and Security Agreement, as amended, which is referred to as the Loan Agreement. As of December 31, 2020 and 2019, the carrying value approximated fair value as borrowings under the Loan Agreement bore interest at variable rates, and the Company believes its credit risk quality is consistent with when the debt was originated. The Company considered the balances outstanding under the Loan Agreement to be Level II liabilities as of December 31, 2020 and 2019. See “Note 7—Debt.”

Prior to the IPO, the Company measured its redeemable convertible preferred stock warrant liability at fair value on a recurring basis, and it was classified within Level III because the warrants were valued using a Black-Scholes valuation model, for which some inputs are unobservable in the market. The valuation methodology and underlying assumptions are discussed further in Note 9. For the year ended December 31, 2018, the Company recorded $6.1 million related to the revaluation of its redeemable convertible preferred stock warrant liability, which is included in other (income) expense, net in the Company’s consolidated statement of operations. Upon the closing of the IPO in October 2018, the redeemable convertible preferred stock warrant converted to a common stock warrant. As such, the Company reclassified its redeemable convertible preferred stock warrant liability to additional paid-in capital.

The following table sets forth a summary of the changes in the fair value of the redeemable convertible preferred stock warrant liability (in thousands):







Fair value at December 31, 2017	$	1,104
Change in fair value	6,056
Conversion to common stock warrant in connection with the initial public offering	(7,160)
Fair value at December 31, 2018	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Components

12 Months Ended

Dec. 31, 2020

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

Property and Equipment, Net

Property and equipment, net consisted of the following as of December 31, 2020 and 2019 (in thousands):


	2020		2019
Computer equipment and software	$	4,819	$	3,613
Internal-use software and platform development costs	20,727		12,726
Leasehold improvements	14,613		10,576
Office furniture and fixtures	3,354		2,454
Total property and equipment	43,513		29,369
Less: Accumulated depreciation	(15,374)		(7,915)
Property and equipment, net	$	28,139	$	21,454

Depreciation expense related to property and equipment was $3.6 million, $2.8 million, and $2.2 million for the years ended December 31, 2020, 2019, and 2018, respectively.

The Company capitalized $8.0 million, $6.4 million, and $4.0 million of internal-use software and platform development costs during the years ended December 31, 2020, 2019, and 2018, respectively.

Amortization expense related to the capitalized internal-use software and platform development costs was $3.9 million for the year ended December 31, 2020, of which $2.9 million was included in cost of revenue related to developed technology used on the work marketplace. Amortization expense related to the capitalized internal-use software and platform development costs was $1.2 million for the year ended December 31, 2019, of which $0.9 million was included in cost of revenue related to developed technology used on the work marketplace. Amortization expense related to the capitalized internal-use software and platform development costs was $0.1 million for the year ended December 31, 2018.

Intangible Assets, Net

All of the Company’s identifiable intangible assets were acquired in March 2014 from the Elance-oDesk Combination. Intangible assets, net consisted of the following (in thousands):


	As of December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trade names	$	2,293	$	2,293	$	—
User relationships	18,678		18,011		667
Developed technology	10,356		10,356		—
Domain names	529		529		—
Total	$	31,856	$	31,189	$	667


	As of December 31, 2019
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trade names	$	2,293	$	2,293	$	—
User relationships	18,678		15,343		3,335
Developed technology	10,356		10,356		—
Domain names	529		529		—
Total	$	31,856	$	28,521	$	3,335

Total amortization expense of intangible assets was $2.7 million for each of the years ended December 31, 2020, 2019, and 2018. Amortization expense is included in general and administrative expenses. As of December 31, 2020, the remaining useful life for user relationships was 0.3 years.

As of December 31, 2020, the estimated future amortization expense for the acquired intangible assets is as follows (in thousands):


Year Ended December 31,	Estimated Amortization Expense
2021	$	667


Total	$	667

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following as of December 31, 2020 and 2019 (in thousands):


	2020		2019
Accrued compensation and related benefits	$	14,007	$	5,344
Accrued freelancer costs	1,235		622
Accrued indirect taxes	3,818		2,401
Accrued vendor expenses	8,662		5,485
Accrued payment processing fees	1,219		832
Operating lease liability, current	3,725		3,214
Other	202		444
Total accrued expenses and other current liabilities	$	32,868	$	18,342

Operating Leases

The Company leases office space and certain equipment under various operating leases, with the vast majority of its lease portfolio consisting of operating leases for office space. The Company has also entered into arrangements where it acts as a sublessor in its leases of office space. The Company has not entered into any significant finance, sales-type, or direct financing leases.

The Company’s significant judgments include determining whether an arrangement is or contains a lease, the determination of the discount rate used to calculate the lease liability, and whether or not lease incentives are reasonably certain to occur in the initial measurement of the lease liability. Operating lease assets and lease liabilities are recognized at commencement date and initially measured based on the present value of lease payments over the defined lease term. Lease expense is recognized on a straight-line basis over the lease term.

A contract is or contains an embedded lease if the contract meets all of the below criteria:

•There is an identified asset;

•The Company has the right to obtain substantially all of the economic benefit of the asset; and

•The Company has the right to direct the use of the asset.

For initial measurement of the present value of lease payments and for subsequent measurement of lease modifications, the Company is required to use the rate implicit in the lease. Since the majority of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate, which is a collateralized rate. The application of the incremental borrowing rate is performed on a lease-by-lease basis and approximates the rate at which the Company could borrow, on a secured basis for a similar term, an amount equal to its lease payments in a similar economic environment.

The Company’s leases have remaining lease terms of approximately one year to eight years, which may include the option to extend the lease. The Company includes lease payments associated with renewal options in its operating lease asset and liability only when it becomes reasonably certain the company will exercise the renewal option. The Company has not included renewal options for any of its operating leases in its determination of lease liabilities. The Company does not have lease agreements with residual value guarantees, sale leaseback terms, or material restrictive covenants. Leases with an initial term of 12 months or less are not recognized on the consolidated balance sheet. The Company recognizes lease expense for these leases on a straight-line basis over the lease term.

The following table summarizes the Company’s operating lease assets and lease liabilities as of December 31, 2020 and 2019 (in thousands):


Balance Sheet Classification		2020		2019
Assets
Operating—noncurrent	Operating lease asset	$	19,729	$	21,908
Liabilities
Operating—current	Accrued expenses and other current liabilities	3,725		3,214
Operating—noncurrent	Operating lease liability, noncurrent	20,506		21,186
Total lease liabilities		$	24,231	$	24,400

For the years ended December 31, 2020 and 2019, operating lease cost, inclusive of variable lease charges, was $6.0 million and $5.9 million, respectively, and sublease income recognized was approximately $0.3 million and $0.4 million, respectively. For the years ended December 31, 2020 and 2019, charges related to operating leases that are variable, and therefore not included in the measurement of the lease liabilities, were $0.7 million and $0.6 million, respectively. The Company made lease payments of $3.3 million and $3.3 million during the years ended December 31, 2020 and 2019, respectively.

On January 1, 2020, the Company commenced an operating lease of one additional floor in its Chicago, Illinois office. As a result, the Company recognized a $1.7 million operating lease asset and $1.7 million operating lease liability on January 1, 2020, which are included in operating lease asset and operating lease liability, noncurrent, respectively, on the Company’s consolidated balance sheet as of December 31, 2020. The lease has an initial term of five years with the option to renew for an additional five years at the end of the initial lease term. Total minimum lease payments under the initial term are $2.1 million. For the initial measurement of the present value of the lease payments associated with this lease, the Company used its incremental borrowing rate, which is a collateralized rate and approximates the rate at which the Company could borrow, on a secured basis for a similar term, an amount equal to its lease payments in a similar economic environment.

As of December 31, 2020 and 2019, the Company had no material finance leases.

The following table shows the Company’s future lease commitments due in each of the next five years and thereafter for operating leases (in thousands):


Year Ended December 31,	Leases
2021	$	3,919
2022	5,391
2023	6,519
2024	5,843
2025	2,356
Thereafter	4,937

Total lease payments	28,965
Adjustment for discount to present value	(4,734)
Total	$	24,231

As of and for the year ended December 31, 2020, the weighted-average remaining lease term is 5.4 years, and the weighted-average discount rate is 5.80%.

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Letters of Credit In conjunction with the operating lease agreements, as of December 31, 2020 and 2019, the Company had three irrevocable letters of credit outstanding in the aggregate amount of $1.0 million and $0.8 million, respectively. The letters of credit are collateralized by restricted cash in the same amount. No amounts had been drawn against these letters of credit as of December 31, 2020 and 2019. Contingencies The Company accrues contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. Potential contingencies may include various claims and litigation or non-income tax matters that arise from time to time in the normal course of business. Due to uncertainties inherent in such contingencies, the Company can give no assurance that it will prevail in any such matters, which could subject the Company to significant liability or damages. Any claims, litigation, or other contingencies could have an adverse effect on the Company’s business, financial position, results of operations or cash flows in or following the period that claims, litigation or other contingencies are resolved. As of December 31, 2020 and 2019, the Company was not a party to any material legal proceedings or claims, nor is the Company aware of any pending or threatened litigation or claims, including non-income tax matters, that could reasonably be expected to have a material adverse effect on its business, operating results, cash flows, or financial condition. Accordingly, the amounts accrued for contingencies for which the Company believes a loss is probable were not material as of and for the years-ended December 31, 2020 and 2019. Indemnification The Company has indemnification agreements with its officers, directors, and certain key employees to indemnify them while they are serving in good faith in their respective positions. In the ordinary course of business, the Company enters into contractual arrangements under which it agrees to provide indemnification of varying scope and terms to clients, business partners, vendors, and other parties, including, but not limited to, losses arising out of the Company’s breach of such agreements, claims related to potential data or information security breaches, intellectual property infringement claims made by third parties, and other liabilities relating to or arising from the Company’s products and services or its acts or omissions. In addition, subject to the terms of the applicable agreement, as part of the Company’s Upwork Enterprise offering, the Company indemnifies clients that subscribe to worker classification services for losses arising from worker misclassification. It is not possible to determine the maximum potential loss under these indemnification provisions due to the Company’s limited history of prior indemnification claims and the facts and circumstances involved in each particular provision.

Debt

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Debt

The following table presents the carrying value of the Company’s debt obligations as of December 31, 2020 and 2019 (in thousands):


	2020			2019
First term loan—18 months of interest-only payments ended in March 2019 followed by 36 equal monthly installments of principal plus interest, maturing March 2022; interest at prime plus 0.25% per annum	$	6,250		$	11,250
Second term loan—17 months of interest-only payments ended in March 2019 followed by 42 equal monthly installments of principal plus interest, maturing September 2022; interest at prime plus 0.25% per annum	4,500			7,071

Total debt	10,750			18,321
Less: Unamortized debt discount issuance costs	(27)			(38)
Balance	10,723			18,283
Debt, current	(7,581)			(7,584)
Debt, noncurrent	$	3,142		$	10,699
Weighted-average interest rate	5.64		%	6.93		%

In September 2017, the Company entered the Loan Agreement, which was subsequently amended in November 2017, September 2018, March 2019, and August 2020. Under the Loan Agreement, the aggregate amount of the facility is up to $49.0 million, consisting of a term loan in the original principal amount of $15.0 million, which is referred to as the First Term Loan, a term loan in the original principal amount of $9.0 million, which is referred to as the Second Term Loan and, together with the First Term Loan, the Term Loans, and a revolving line of credit, which permits borrowings of up to $25.0 million subject to customary conditions. The Company has granted its lender first-priority liens against substantially all of its assets, as collateral, excluding the Company’s intellectual property (but including proceeds therefrom) and the funds and assets held by the Company’s subsidiary, Upwork Escrow Inc. The Company has also agreed to a negative pledge on its intellectual property. The Loan Agreement also requires that the Company maintain an adjusted quick ratio of 1.75. The Loan Agreement also includes a restrictive covenant on dividend payments other than dividends paid solely in common stock.

In March 2019, the Company entered into a third amendment to the Loan Agreement, which, among other changes, (i) amended the adjusted quick ratio financial covenant to provide that the Company will maintain an adjusted quick ratio of 1.75 to 1.00

(previously 1.30 to 1.00), (ii) reduced the frequency with which the Company is required to provide certain financial information to the lender during periods in which it maintains an adjusted quick ratio of 2.50 to 1.00, and (iii) eliminated the minimum EBITDA covenant with which the Company was required to comply. The Company was in compliance with its covenants under the Loan Agreement as of December 31, 2020 and 2019.

In August 2020, the Company entered into a fourth amendment to the Loan Agreement that, among other things, extended the maturity date of the revolving line of credit from September 2020 to September 2022 and eliminated a formula-based restriction that prohibited the Company from borrowing funds under the revolving line of credit in an amount that exceeded a specified percentage of eligible trade and client accounts receivable.

To the extent the Company has not yet collected funds for hourly billings from clients that are in-transit due to timing differences in receipt of cash from clients, the Company may utilize the revolving line of credit to satisfy customary escrow funding requirements. The Company drew down $25.0 million under the revolving line of credit for such purpose in each of March and June 2019, which the Company subsequently repaid in April and July 2019, respectively. The Company also drew down $15.0 million under the revolving line of credit for such purpose in September 2018, which the Company subsequently repaid in October 2018. Additionally, in October 2018, the Company used part of the net proceeds from the IPO to repay $10.0 million of indebtedness owed under the revolving line of credit.

Pursuant to the terms of the Loan Agreement, the Company commenced repayment on the Term Loans in April 2019. During the year ended December 31, 2020, the Company repaid $5.0 million and $2.6 million related to the First Term Loan and the Second Term Loan, respectively. During the year ended December 31, 2019, the Company repaid $3.8 million and $1.9 million related to the First Term Loan and the Second Term Loan, respectively.

Amortization expense related to the debt discount was immaterial for the years ended December 31, 2020, 2019, and 2018.

Future maturities of principal payments, excluding potential early payments, as of December 31, 2020, were expected to be as follows (in thousands):


Year Ended December 31,	Principal Payments
2021	$	7,571
2022	3,179




Total	$	10,750

Redeemable Convertible Preferred Stock	12 Months Ended
Redeemable Convertible Preferred Stock	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock Prior to the IPO, the Company financed its operations and capital expenditures primarily through sales of convertible preferred stock, bank borrowings, and utilization of cash generated from operations in the periods in which the Company generated cash flows from operations. The Company completed its IPO in October 2018, in which the Company issued and sold 7,840,908 shares of common stock at a public offering price of $15.00 per share, before deducting underwriting discounts and commissions and offering expenses payable by the Company. As a result, all of the Company’s 61,279,079 shares of then-outstanding redeemable convertible preferred stock automatically converted into shares of common stock on a one-for-one basis. Therefore, there were no issued or outstanding shares of redeemable convertible preferred stock as of December 31, 2020 and 2019.

Preferred and Common Stock Warrants

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Preferred and Common Stock Warrants

Redeemable Convertible Preferred Stock Warrants

As a result of the Elance-oDesk Combination, a redeemable convertible preferred stock warrant that was originally issued by Elance prior to the Elance-oDesk Combination became exercisable to purchase up to 124,506 and 273,825 shares of the Company’s Series A-1 and Series A-2 redeemable convertible preferred stock, respectively, at an exercise price of $3.13 per share. Upon completion of the IPO, this warrant converted to a common stock warrant exercisable for the same number of shares and was reclassified to additional paid-in capital. The common stock warrant was outstanding and exercisable as of December 31, 2018. In April 2019, this common stock warrant was exercised in full at a total cost of $1.2 million. In lieu of a cash payment, the holder of the warrant surrendered 64,646 shares of common stock to cover the exercise price. The Company issued 333,685 shares of common stock upon the exercise of this common stock warrant.

Prior to the IPO, the Company estimated the fair value of each redeemable convertible preferred stock warrant using the Black-Scholes valuation model. For the year ended December 31, 2018, the Company recorded $6.1 million related to the revaluation of its redeemable convertible preferred stock warrant liability, which is included in other (income) expense, net in the Company’s consolidated statement of operations. The following assumptions were used to calculate the estimated fair value of the then-outstanding warrants until the closing date of the Company’s IPO:



Dividend yield	0	%
Expected term (in years)	2.75
Risk-free interest rates	1.8	%
Expected volatility	34.6	%

Common Stock Warrant

As a result of the Elance-oDesk Combination, a common stock warrant that was originally issued by oDesk prior to the Elance-oDesk Combination became exercisable to purchase up to 45,286 shares of common stock at an exercise price of $0.06 per share. In 2018, the Company issued 45,286 shares of common stock upon the exercise of this common stock warrant.

In 2018, the Company established The Upwork Foundation initiative. The program includes a donor-advised fund created through the Tides Foundation. In May 2018, the Company issued a warrant to purchase 500,000 shares of its common stock at an exercise price of $0.01 per share to the Tides Foundation. The vesting and exercisability provisions of the warrant became effective upon the Company’s IPO in October 2018. This warrant is exercisable as to 1/10th of the shares on each anniversary of the IPO, with proceeds from the sale of such shares to be donated in accordance with the Company’s directive.

In 2019, this warrant was exercised as to all 50,000 of the then-vested and exercisable shares. In lieu of a cash payment, the holder of the warrant surrendered 37 shares of common stock to cover the exercise price. The Company issued 49,963 shares of common stock upon the exercise of this common stock warrant.

In 2020, this warrant was exercised as to all 50,000 of the then-vested and exercisable shares. In lieu of a cash payment, the holder of the warrant surrendered 29 shares of common stock to cover the exercise price. The Company issued 49,971 shares of common stock upon the exercise of this common stock warrant.

For the years ended December 31, 2020, 2019, and 2018, the Company recorded $0.8 million, $0.7 million, and $0.2 million, respectively, of expense related to this warrant, which is included in general and administrative expense in the Company’s consolidated statement of operations.

Preferred and Common Stock

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Preferred and Common Stock

Preferred Stock

As of December 31, 2020 and 2019, the Company was authorized to issue up to 10,000,000 shares of undesignated preferred stock, $0.0001 par value per share. The Company did not have any outstanding shares of preferred stock as of December 31, 2020 and 2019.

Common Stock

Holders of common stock are entitled to one vote per share and are entitled to receive dividends, if any, on a pro rata basis whenever funds are legally available and when, as, and if declared by the Company’s board of directors.

As of December 31, 2020 and 2019, the Company was authorized to issue 490,000,000 shares of common stock. As of December 31, 2020 and 2019, the Company had reserved shares of common stock for future issuance as follows:


	2020	2019
Options issued and outstanding	4,858,590	15,140,579
RSUs issued and outstanding	5,568,225	2,503,182

Warrant to purchase common stock	400,000	450,000


Remaining shares reserved for future issuances under 2018 Equity Incentive Plan	18,332,765	16,091,801
Remaining shares reserved for future issuances under 2018 Employee Stock Purchase Plan	2,419,154	1,994,971
Total	31,578,734	36,180,533

Stock-Based Compensation

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation

Equity Incentive Plans

Assumed Awards

In connection with the Elance-oDesk Combination, the Company assumed substantially all stock options outstanding under the Elance 1999 Stock Option Plan, which is referred to as the Elance 1999 Plan, and the Elance 2009 Stock Option Plan, which is referred to as the Elance 2009 Plan. Such assumed options were converted into options to purchase the Company’s common stock. In addition, all stock options outstanding under the oDesk Corporation 2004 Stock Plan, which is referred to as the oDesk Plan, were converted into options to purchase shares of the Company’s common stock, with the number of shares that could be purchased under each option reduced by approximately 16.14%. The exercise price of all options was simultaneously increased such that the then-aggregate exercise price payable by holders did not change. These options generally vest over a four-year period from the original date of grant and expire ten years from the original grant date.

2014 Equity Incentive Plan

In March 2014, the Company’s board of directors and, in June 2014, the Company’s stockholders approved the 2014 Equity Incentive Plan, which is referred to as the 2014 EIP. The total number of shares of common stock reserved and available for grant and issuance pursuant to such plan was originally 12,462,985 plus (i) shares that were then subject to outstanding option grants under the oDesk Plan, the Elance 1999 Plan, and the Elance 2009 Plan, which are referred to collectively as the Prior Plans, but subsequently ceased to be subject to an award for any reason other than exercise of a stock option, (ii) shares that had been reserved but not subject to any outstanding awards under the Prior Plans and (iii) shares issued under the Prior Plans that were repurchased, forfeited, or used to pay employee withholding or exercise price obligations. The number of shares available for grant under the 2014 EIP was increased by 3,001,091 shares, 4,500,000 shares and 100,000 shares in August 2014, October 2017 and August 2018, respectively. Under the terms of the 2014 EIP, incentive stock options may be granted at prices not less than 100% of the fair value of the Company’s common stock on the date of grant unless determined in writing by the Company’s board of directors. The options granted under the 2014 EIP generally vest over a four-year period from the original date of grant and expire ten years from the original grant date.

2018 Equity Incentive Plan

In 2018, the Company’s board of directors and stockholders each adopted the 2018 Equity Incentive Plan, which is referred to as the 2018 EIP, which became effective on the date immediately prior to the date of the IPO. A total of 10,701,505 shares of common stock were initially reserved for issuance pursuant to future awards under the 2018 EIP. On January 1 of each year, shares available for issuance are increased based on the provisions of the 2018 EIP. Any shares subject to outstanding awards under the 2014 EIP that are canceled or repurchased subsequent to the 2018 EIP’s effective date are returned to the pool of shares reserved for issuance under the 2018 EIP. Awards granted under the 2018 EIP may be (i) incentive stock options, (ii) nonqualified stock options, (iii) RSUs, (iv) restricted stock awards, or (v) stock appreciation rights, as determined by the Company’s board of directors or compensation committee at the time of grant.

Pursuant to the terms of the 2018 EIP, the number of shares available for grant was increased by 5,680,219 shares in January 2020.

On December 8, 2019, which is referred to as the Modification Date, the Company entered into a transition agreement, which is referred to as the Transition Agreement, with Stephane Kasriel pursuant to which Mr. Kasriel tendered his resignation as the Company’s President and Chief Executive Officer effective as of December 31, 2019, which is referred to as the Resignation Date. The Transition Agreement provides that Mr. Kasriel will be entitled to any amounts that Mr. Kasriel has earned under the Bonus Plan and that Mr. Kasriel will become a special advisor to the Board through April 30, 2021 pursuant to an advisory services agreement, which is referred to as the Advisory Agreement. Among other terms, the Advisory Agreement provides that while he is providing advisory services, (i) the Company will pay Mr. Kasriel a fee of $40,000 per calendar month, beginning January 1, 2020 and ending December 31, 2020, (ii) the vesting terms of certain of Mr. Kasriel’s outstanding stock options was modified to allow for vesting to continue through the term of the Advisory Agreement, and (iii) the period of time over which Mr. Kasriel can exercise certain of his outstanding stock options was extended to the later of December 31, 2020 or three months following such date as he ceases to provide services to the Company. The Company accounted for the modification of any vested non-qualified options as a Type I (probable-to-probable) modification given that the options were already vested. The incremental fair value, recognized as of the Modification Date, was measured by taking the difference between the fair value of the options immediately before and after the Modification Date. Additionally, the Company accounted for the modification of any unvested options as a Type III (improbable-to-probable) modification. Accordingly, the Company reversed the cumulative compensation cost recognized for the original award, and immediately recognized the fair value of the modified award as the Company concluded the services to be provided by Mr. Kasriel beyond December 31, 2019 were nonsubstantive.

As a result, for the year ended December 31, 2019, the Company recorded $3.5 million of additional stock-based compensation expense related to the Transition Agreement.

The fair values of the awards modified by the Transition Agreement were estimated using the Black-Scholes valuation model with the following assumptions:


Dividend yield	—	%
Expected term (in years)	0.3 - 1.3
Risk-free interest rates	1.5% - 1.6%
Expected volatility	38% - 39%

Determination of Fair Value

The Company did not grant any stock option awards during the years ended December 31, 2020 and 2019. For the year ended December 31, 2018, the fair value of stock options granted to employees was estimated on the grant date using the Black-Scholes valuation model with the following assumptions:



Dividend yield	—	%
Expected term (in years)	5.2 - 6.1
Risk-free interest rates	2.5% - 2.9%
Expected volatility	38% - 45%

Dividend Yield —The dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to do so.

Expected Term —The expected term represents the period that the Company’s stock-based awards are expected to be outstanding. For awards containing only service conditions, the Company determines the expected term using the simplified method as the Company does not have sufficient historical information to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the options. The Company uses relevant data, including past exercise patterns, if available, to determine the expected term for performance-based awards.

Risk-Free Interest Rate —The risk-free interest rate is based on the United States Treasury yield curve in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the option’s expected term.

Expected Volatility —Since the Company does not have a sufficient trading history of its common stock, the expected volatility is derived from the average historical stock volatilities of several unrelated public companies within the Company’s industry that the Company considers to be comparable to its business over a period equivalent to the expected term of the stock option grants.

Fair Value of Common Stock —Given the absence of a public trading market prior to the IPO, the Company’s board of directors considered numerous objective and subjective factors to determine the fair value of its common stock at each grant date. These factors included, but were not limited to: (i) independent contemporaneous third-party valuations of common stock; (ii) the prices for the Company’s redeemable convertible preferred stock sold to outside investors; (iii) the rights and preferences of redeemable convertible preferred stock relative to common stock; (iv) the lack of marketability of its common stock; (v) developments in the business; and (vi) the likelihood of achieving a liquidity event, such as an IPO or sale of the Company, given prevailing market conditions. Subsequent to the IPO, the fair value of common stock is based on the closing price of the Company’s common stock, as reported on The Nasdaq Global Select Market on the date of grant.

The following table summarizes activity under the Company’s stock option plans:


	Number of Shares Underlying Outstanding Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)








Balances at December 31, 2019	15,140,579	$	3.61	6.19	$	106,967

Exercised	(9,065,976)	3.42
Forfeited and canceled	(1,216,013)	4.08
Balances at December 31, 2020	4,858,590	3.83		5.80	149,046
Vested and exercisable as of December 31, 2020	3,876,252	3.74		5.55	119,303
Vested and expected to vest as of December 31, 2020	4,858,590	3.83		5.80	149,046

Before the IPO, the aggregate intrinsic value represented the difference between the exercise price of the options and the estimated fair value of the Company’s common stock as determined by its board of directors. Following the IPO, the aggregate intrinsic value represented the difference between the exercise price of the options and the closing price of the Company’s common stock on The Nasdaq Global Select Market on the day prior to the date of exercise. The intrinsic value of options exercised was $124.1 million, $73.0 million, and $18.0 million for the years ended December 31, 2020, 2019, and 2018, respectively.

For the year ended December 31, 2018, the weighted-average grant-date fair value of options granted was $3.65. As of December 31, 2020, total unrecognized stock-based compensation cost was $1.9 million, which is expected to be generally recognized on a straight-line basis over a weighted-average period of 1.2 years.

The fair value of RSUs awarded to employees is based on the closing price of the Company’s common stock, as reported on The Nasdaq Global Select Market on the date of grant.

The following table summarizes the RSU activity and related information under the 2018 EIP:


	Number of RSUs Outstanding	Weighted-Average Grant Date Fair Value
Unvested balance - January 1, 2020	2,503,182	$	15.82
Granted	5,750,034	10.96
Vested	(1,590,225)	13.15
Forfeited/canceled	(1,094,766)	12.70
Unvested balance - December 31, 2020	5,568,225	$	12.20

During 2018, 35,494 fully vested RSUs were granted to a consultant of the Company, which totaled $0.5 million. The consultant’s estimated tax liability associated with this vesting was $0.2 million. To satisfy this tax liability, the consultant surrendered 12,648 shares of common stock to the Company. The associated tax liability was paid in full prior to December 31, 2018.

For the years ended December 31, 2020, 2019, and 2018, the weighted-average grant-date fair value of RSUs granted was $10.96, $16.15, and $15.00, respectively. For the years ended December 31, 2020 and 2019, the fair value of RSUs vested was $20.3 million and $2.6 million, respectively. For the year ended December 31, 2018, the fair value of RSUs vested was immaterial. As of December 31, 2020, there was $62.8 million of unrecognized stock-based compensation expense related to outstanding RSUs to employees that is expected to be recognized over a weighted-average period of 2.9 years.

2018 Employee Stock Purchase Plan

In August 2018, the Company’s board of directors and stockholders each adopted the 2018 ESPP, which became effective prior to the completion of the IPO. A total of 1,700,000 shares of common stock was initially reserved for issuance under the 2018 ESPP. On January 1 of each year, shares available for issuance are increased based on the provisions of the 2018 ESPP. The 2018 ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount of up to 15% through payroll deductions of their eligible compensation, subject to any plan limitations. Except for the initial offering period, the 2018 ESPP provides for 24-month offering periods beginning November 15 and May 15 of each year, and each offering period consists of four 6-month purchase periods. Pursuant to the terms of the 2018 ESPP, in January 2020, the number of shares of common stock available for issuance was increased by 908,835 shares.

For the years ended December 31, 2020, 2019, and 2018, the assumptions used to determine the fair value of the shares to be awarded was estimated on the grant date using the Black-Scholes valuation model with the following assumptions:


	2020	2019	2018
Dividend yield	0%	0%	0%
Expected term (in years)	0.5 - 2.0	0.5 - 2.0	0.5 - 2.0
Risk-free interest rates	0.1% - 0.2%	1.5% - 2.4%	2.4% - 2.9%
Expected volatility	50% - 82%	38% - 47%	37%

On each purchase date, eligible employees may purchase the Company’s common stock at a price per share equal to 85% of the lesser of (1) the fair market value of the Company’s common stock on the offering date or (2) the fair market value of the Company’s common stock on the purchase date. In the event the price is lower on the last day of any purchase period, that price is used as the purchase price for that purchase period.

Additionally, in the event the fair market value of the Company’s common stock on the first day of a subsequent offering period is less than the fair market value of the Company’s common stock on the offering date of the current offering period, the offering period resets, and the new lower price becomes the new offering price for a new 24 month offering period. During the year ended December 31, 2020, the Company issued 484,652 shares of common stock under the 2018 ESPP.

As of December 31, 2020, there was $2.3 million of unrecognized stock-based compensation expense that is expected to be recognized over the remaining term of the respective offering periods.

Stock-Based Compensation

The following table summarizes the components of stock-based compensation expense recognized in the consolidated statements of operations for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Cost of revenue	$	779	$	456	$	282
Research and development	9,783		6,471		3,258
Sales and marketing	4,440		2,609		1,637
General and administrative	10,506		9,262		5,184
Total	$	25,508	$	18,798	$	10,361

Stock-Based Compensation to Employees

Stock-based compensation expense related to employees for the year ended December 31, 2020 was $2.5 million, $20.0 million, and $3.2 million related to stock option grants, RSU grants, and the 2018 ESPP, respectively. Stock-based compensation expense related to employees for the year ended December 31, 2019 was $8.5 million, $7.9 million, and $2.6 million related to stock option grants, RSU grants, and the 2018 ESPP, respectively. Stock-based compensation expense related to employees for the year ended December 31, 2018 was $8.6 million, $1.1 million, and $0.6 million related to stock option grants, RSUs, and the 2018 ESPP, respectively.

Net Loss per Share

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Net Loss Per Share

Net Loss per Share

The following table sets forth the computation of the Company’s basic and diluted net loss per share for the years ended December 31, 2020, 2019, and 2018 (in thousands, except share and per share data):


	2020		2019		2018
Numerator:
Net loss	$	(22,867)	$	(16,659)	$	(19,907)



Denominator:
Weighted-average shares used to compute net loss per share, basic and diluted	118,698,567		109,814,604		52,327,518
Net loss per share, basic and diluted	$	(0.19)	$	(0.15)	$	(0.38)

For the years ended December 31, 2020, 2019, and 2018, the following potentially dilutive shares were excluded from the computation of diluted net loss per share because including them would have been anti-dilutive:


	2020	2019	2018
Options to purchase common stock	4,858,590	15,140,579	23,774,279

Common stock issuable upon exercise of common stock warrants	400,000	450,000	898,331

Common stock issuable upon vesting of restricted stock units	5,568,225	2,503,182	288,460
Common stock issuable in connection with employee stock purchase plan	540,580	1,651,263	—
Total	11,367,395	19,745,024	24,961,070

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

For the years ended December 31, 2020, 2019, and 2018, the loss before income taxes consisted of the following (in thousands):


	2020		2019		2018
Domestic	$	(22,748)	$	(16,658)	$	(19,925)
Foreign	31		27		33
Total loss before income taxes	$	(22,717)	$	(16,631)	$	(19,892)

For the years ended December 31, 2020, 2019, and 2018, the components of the income tax provision were as follows (in thousands):


	2020		2019		2018
Current:
Federal	$	(19)	$	—	$	—
State	(127)		(26)		(11)
Foreign	(4)		(2)		(4)
Total current	$	(150)	$	(28)	$	(15)
Deferred:
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	—		—		—
Total deferred	$	—	$	—	$	—
Total income tax benefit (provision)	$	(150)	$	(28)	$	(15)

The Company had an effective tax rate of (0.66)%, (0.17)%, and (0.07)% for the years ended December 31, 2020, 2019, and 2018, respectively. The reconciliation of the statutory federal income tax rate to the Company’s effective tax rate for the years ended December 31, 2020, 2019, and 2018 were as follows:


	2020		2019		2018
Tax at federal statutory rate	21.00	%	21.00	%	21.00	%
State tax, net of federal benefit	(0.49)		(0.27)		1.88
Stock-based compensation	94.02		51.45		(5.84)
Warrant expense	—		—		(6.98)
Other items	(0.59)		(4.34)		(1.46)
Research and development credits	9.74		13.74		10.54
Net operating loss expiration	(14.00)		(18.33)		—
Change in valuation allowance	(110.34)		(63.42)		(19.21)
Effective tax rate	(0.66)	%	(0.17)	%	(0.07)	%

Deferred income taxes reflect the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. As of December 31, 2020 and 2019, the significant components of the Company’s deferred tax assets and liabilities were as follows (in thousands):


	2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	77,230	$	48,988
Stock-based compensation	230		4,192
Operating lease liability	5,555		10,248
Non-deductible accrued expenses, reserves and other	4,903		2,596
Research and development credits	11,352		8,762
Gross deferred tax assets	99,270		74,786
Valuation allowance	(92,390)		(63,542)
Total deferred tax assets	6,880		11,244
Deferred tax liabilities:
Acquired intangible assets	(89)		(693)
Operating lease asset	(4,523)		(9,202)
Depreciation and amortization	(2,268)		(1,349)
Total deferred tax liabilities	(6,880)		(11,244)
Net deferred tax assets	$	—	$	—

The change in valuation allowance for deferred tax assets was as follows for the periods presented (in thousands):


Year Ended December 31,	Balance at Beginning of Year		Additions Charged to Costs & Expenses		Additions Charged to Other Accounts		Deductions		Balance at End of Year

2020	$	63,542	$	28,848	$	—	$	—	$	92,390
2019	49,439		14,103		—		—		63,542
2018	45,364		4,075		—		—		49,439

The Company records a full valuation allowance of $92.4 million and $63.5 million as of December 31, 2020 and 2019, respectively, against its net deferred tax assets. The Company determines its valuation allowance on deferred tax assets by considering both positive and negative evidence in order to ascertain whether it is more likely than not that deferred tax assets will be realized. Realization of deferred tax assets is dependent upon the generation of future taxable income, if any, the timing and amount of which are uncertain. Due to the history of losses the Company has generated in the past, the Company believes that it is not more likely than not that all of the deferred tax assets can be realized as of December 31, 2020. Accordingly, the Company has recorded a full valuation allowance on its deferred tax assets.

The Company has federal net operating loss, which is referred to as NOL, carryforwards of approximately $343.1 million and $220.4 million as of December 31, 2020 and 2019, respectively. The federal NOLs generated in the years ended December 31, 2017 and prior are subject to expiration, including $15.1 million that expired in 2020 and $21.6 million that will expire in 2021. NOLs originating before January 1, 2018, are eligible to offset taxable income, if not otherwise limited under Internal Revenue Code, which is referred to as IRC, §382 limitations. NOLs generated after December 31, 2017, have an infinite carryforward period and subject to 80% deduction limitation based upon pre-NOL deduction taxable income. The Company has California NOL carryforwards of approximately $72.9 million and $50.3 million as of December 31, 2020 and 2019, respectively. California NOLs generated in the years ended December 31, 2008 through 2018 will begin to expire in 2028. California NOLs generated before 2008 have expired in accordance the California Revenue Taxation Code and related regulations.

The Company has federal research and development credits, which are referred to as Credits, of approximately $12.0 million and $10.1 million as of December 31, 2020 and 2019, respectively. In 2020, $0.2 million of federal research and development credits expired and the remaining carryforward is subject to expiration through 2039. The Company has California Credits of approximately $13.1 million and $11.3 million as of December 31, 2020 and 2019, respectively. California Credits have an infinite carryforward period.

Utilization of the NOL and Credit carryforwards that were generated prior to January 1, 2018, may be subject to a substantial annual limitation due to ownership change limitations that may have occurred or that could occur in the future, as required by IRC §382 and §383, as well as similar state provisions.

Uncertain Tax Positions

As of December 31, 2020, the Company’s total amount of unrecognized tax benefits was $13.3 million, none of which would impact the Company’s effective tax rate, if recognized.

For the years ended December 31, 2020, 2019, and 2018, the activity related to the unrecognized tax benefits were as follows (in thousands):


	2020		2019		2018
Gross unrecognized tax benefits—beginning balance	$	12,782	$	10,973	$	10,200
Increase related to tax positions taken during prior year	131		—		108
Decrease related to tax positions taken during prior year	—		(164)		(2)
Increase related to tax positions taken during current year	608		1,973		667
Decrease related to tax positions taken during current year	—		—		—
Decrease related to expiration of unrecognized tax benefit	(183)		—		—
Gross unrecognized tax benefits—ending balance	$	13,338	$	12,782	$	10,973

The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. To the extent accrued interest and penalties do not ultimately become payable, amounts accrued will be reduced and reflected as a reduction of the provision for income taxes in the period that such determination is made. As of December 31, 2020, the Company did not currently recognize any penalties or interest charges relating to uncertain tax positions. The Company does not anticipate the recorded reserves to change significantly in the next 12 months.

The Company is subject to taxation in the United States and various other state and foreign jurisdictions. Due to certain tax attribute carryforwards, the tax years 2001 to 2020 remain open to examination by the major taxing jurisdictions in which the Company is subject to tax. As of December 31, 2020, the Company was not under examination by the Internal Revenue Service or any state or foreign tax jurisdiction.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Segment and Geographical Information

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Segment and Geographical Information

The Company operates as one operating and reportable segment for purposes of allocating resources and evaluating financial performance.

The following table sets forth total revenue by type of service for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Marketplace	$	338,152	$	268,284	$	223,831
Managed services	35,476		32,278		29,523
Total	$	373,628	$	300,562	$	253,354

The Company generates its revenue from freelancers and clients. The following table sets forth total revenue by geographic area based on the billing address of its freelancers and clients for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Freelancers:
United States	$	60,861	$	50,154	$	40,313
India	33,109		27,369		25,485
Philippines	22,924		19,660		17,057
Rest of world	109,805		90,259		80,387
Total freelancers	226,699		187,442		163,242
Clients:
United States	107,359		87,241		65,578
Rest of world	39,570		25,879		24,534
Total clients	146,929		113,120		90,112
Total	$	373,628	$	300,562	$	253,354

Substantially all of the Company’s long-lived assets were located in the United States as of December 31, 2020 and 2019.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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+ Details

401(k) Plan	12 Months Ended
401(k) Plan	Dec. 31, 2020
Retirement Benefits [Abstract]
401(k) Plan	401(k) PlanThe Company offers the Upwork Retirement Savings Plan, which is referred to as the Retirement Plan, a defined contribution plan that allows employees to contribute a portion of their salary, subject to the annual limits. Under the Retirement Plan, eligible employees may defer a portion of their pretax salaries, but not more than the statutory limits. The Retirement Plan provides for a discretionary employer cash matching contribution. The Company makes matching cash contributions equal to 50% of each dollar contributed, subject to a maximum contribution of $5,000 annually per participant. The Company’s total expense for the matching contributions was $2.5 million, $2.0 million, and $1.7 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn January 18, 2021, which is referred to as the Grant Date, the compensation committee of the board of directors of the Company approved a stock option grant exercisable for up to 1,500,000 shares of the Company’s common stock to Hayden Brown, the Company’s Chief Executive Officer, under the 2018 EIP, which is referred to as the CEO Award. The CEO Award will vest in sixteen equal quarterly installments, which is referred to as the service condition, subject to the achievement of certain volume weighted-average common stock price targets, which is referred to as the market condition, conditioned upon Ms. Brown’s continued employment as the Chief Executive Officer of the Company. Stock-based compensation expense associated with the CEO Award will be recognized over the longer of the expected achievement period for each of the market condition or service condition.

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States, which is referred to as U.S. GAAP, and include the accounts of Upwork Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Results and disclosure requirements for reporting periods beginning after January 1, 2019 are presented under Topics 606 and 842, while prior period amounts have not been adjusted and continue to be reported under Topics 605 and 840.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates, judgments, and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the periods presented. Such estimates include, but are not limited to: the useful lives of assets; assessment of the recoverability of long-lived assets; goodwill impairment; standalone selling price of material rights and the period of time over which to defer and recognize the consideration allocated to the material rights; allowance for doubtful accounts; liabilities relating to transaction losses; the valuation of warrants; stock-based compensation; and accounting for income taxes. Management bases its estimates on historical experience and on various other assumptions that management believes to be reasonable under the circumstances. The Company evaluates its estimates, assumptions, and judgments on an ongoing basis using historical experience and other factors and revises them when facts and circumstances dictate. Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents The Company classifies as cash and cash equivalents its cash held in checking and interest-bearing accounts and investments in money market funds and commercial paper with maturities of 90 days or less from the date of purchase. Restricted CashAs of December 31, 2020 and 2019, the Company maintained restricted cash of $3.3 million and $2.5 million, respectively, related to cash reserve requirements under the escrow laws and regulations of the California Department of Financial Protection and Innovation and collateral for letters of credit issued in conjunction with operating leases.
Funds Held in Escrow, Including Funds in Transit	Funds Held in Escrow, Including Funds in Transit The Company maintains its users’ funds held in escrow in demand or checking accounts at U.S. financial institutions, as well as three California licensed money transmitters. The balance in these accounts was in excess of federally insured limits as of December 31, 2020 and 2019. Users’ funds held in escrow are denominated exclusively in U.S. dollars. The Company is an internet escrow agent and is therefore required to hold its users’ escrowed funds and escrow funds in transit in trust as an asset and record a corresponding liability for escrow funds payable on its consolidated balance sheets. For this reason, funds held in escrow, including funds in transit, are restricted cash. Escrow funds in transit arise due to the time it takes to clear transactions through external payment networks. When clients fund their escrow account using credit cards, there is a clearing period before the cash is received and settled. Accordingly, the funds are treated as escrow funds in transit until the transaction is settled to the escrow trust bank account or, in the case of international credit card settlements, to the Company’s bank accounts. Escrow regulations require the Company to fund the trust with its own operating cash if there is ever a shortage due to the timing of cash receipts from clients for completed hourly billings.
Marketable Securities	Marketable Securities The Company’s marketable securities consist of commercial paper, treasury bills, and U.S. government securities, all of which have contractual maturities within 24 months from the date of purchase. The marketable securities are available for current operations and are classified as available-for-sale. These marketable securities are carried at estimated fair value with unrealized gains and losses, net of taxes, included within the stockholders’ equity section of the Company’s consolidated balance sheet. The Company periodically assesses its portfolio of debt investments for impairment. For debt securities in an unrealized loss position, this assessment first takes into account the Company’s intent to sell, or whether it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis. If either of these criteria are met, the debt security’s amortized cost basis is written down to fair value through other (income) expense, net. For debt securities in an unrealized loss position that do not meet the aforementioned criteria, the Company assesses whether the decline in fair value below the amortized cost basis resulted from a credit loss or other factors. In making this assessment, the Company considers factors such as the extent to which fair value is less than the amortized cost basis, the financial condition of the issuer, any changes to the rating of the security by a rating agency, and any adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss may exist, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses will be recorded through other (income) expense, net, limited by the amount that the fair value is less than the amortized cost basis. Any additional impairment not recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are reflected as provision for (or reversal of) credit loss expense. Losses are charged against the allowance when management believes the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell are met. These changes are recorded in other (income) expense, net. The Company determines realized gains or losses from the sale of marketable securities on a specific identification method and records such gains or losses as other (income) expense, net within the Company’s consolidated statements of operations. For the year ended December 31, 2020, the gross unrealized gains and losses on the Company’s marketable securities were immaterial. The Company did not record any impairment charges with respect to its marketable securities during the years ended December 31, 2020, 2019, and 2018.
Concentration of Risk	Concentration of Risk Financial instruments that subject the Company to concentration of risk consist primarily of cash, restricted cash, funds held in escrow, including funds in transit, and trade and client receivables. The Company maintains its cash balances with large, high-credit quality financial institutions and other payment companies. At times, such deposits may be in excess of federally insured limits. The Company has not experienced any losses on its deposits. Credit risk on trade receivables is limited as a result of the large size of the Company’s client base as well as a large portion of payments made using pre-authorized credit cards. The Company performs ongoing credit evaluations of its clients and maintains allowances for potential credit losses. For any receivables that are deemed not collectible, losses are recorded when probable and estimable. These losses, when incurred, have been within the range of the Company’s expectations. Three clients each accounted for more than 10% of trade and client receivables as of December 31, 2020. Two clients each accounted for more than 10% of trade and client receivables as of December 31, 2019. For the year ended December 31, 2020, the Company did not have any clients that accounted for more than 10% of total revenue. For the years ended December 31, 2019 and 2018, the Company generated $32.0 million and $29.5 million, respectively, in revenue from one of these clients, which accounted for more than 10% of revenue during the years ended December 31, 2019 and 2018. The Company is dependent upon third parties, such as Amazon Web Services, in order to meet the uptime and performance needs of its users.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, restricted cash, funds held in escrow, including funds in transit, marketable securities, trade and client receivables, prepaid and other current assets, escrow funds payable, debt, and the redeemable convertible preferred stock warrant liability. Prior to the IPO, the redeemable convertible preferred stock warrant liability was remeasured at the end of every period and was carried at fair value. Upon the IPO, the redeemable convertible preferred stock warrant was converted to a common stock warrant and is no longer remeasured. The Company believes that the carrying values of the remaining financial instruments approximate their fair values.
Trade and Client Receivables and Related Allowance for Doubtful Accounts	Trade and Client Receivables and Related Allowance for Doubtful Accounts Trade and client receivables are primarily comprised of receivables from the Company’s managed services offering and amounts receivable from clients for completed work, including amounts in transit. It also includes unbilled amounts due from clients. Trade and client receivables are recorded and stated at realizable value, net of an allowance for doubtful accounts. Credit is extended generally without collateral to the Company’s managed services client and marketplace clients with Upwork Enterprise offerings based on an initial and ongoing evaluation of their financial condition and other factors. In aggregate, gross trade receivables were $15.9 million and $10.3 million and gross client receivables were $32.8 million and $22.1 million as of December 31, 2020 and 2019, respectively. The allowance for doubtful accounts is the Company’s estimate of the probable credit losses on accounts receivable. The Company periodically assesses the collectability of the accounts and determines the allowance recognized by taking into consideration the aging of its receivable balances, historical write-off experience, probability of collection, and other relevant data. Trade and client receivables are written off against the allowance when management determines a balance is uncollectible and no longer actively pursues collection of the receivable.
Derivatives Instruments	Derivative Instruments The Company uses derivative financial instruments not designated as hedges, such as foreign currency forward contracts, to minimize the short-term impact of foreign currency exchange rate fluctuations on certain foreign currency denominated assets and liabilities, as well as certain foreign currency denominated expenses, hedging the gains or losses generated by the re-measurement of significant foreign currency denominated monetary assets and liabilities. The Company does not enter into derivative instruments for speculative or trading purposes and these instruments generally have maturities within 12 months. The foreign currency forward contracts are recorded at fair value and, when in gain positions, are reported within prepaid expenses and other current assets. When in loss positions, the foreign currency forward contracts are recorded within accrued expenses and other current liabilities in the consolidated balance sheets. Gains or losses from changes in the fair value of these foreign currency forward contracts not designated as hedging instruments are recorded in other (income) expense, net to offset the changes in the fair value of the underlying assets or liabilities being hedged. The notional amounts associated with the Company’s foreign currency forward contracts at December 31, 2020 and 2019 were $7.6 million and $5.4 million, respectively, none of which were designated as cash flow hedges. The carrying values of the foreign currency forward contracts approximated their fair values due to their relatively short settlement durations. The fair values of the Company’s outstanding foreign currency forward contracts not designated as hedging instruments as of December 31, 2020 and 2019 were not material. Losses on foreign currency forward contracts not designated as hedging instruments were $0.6 million for the year ended December 31, 2020. Gains on foreign currency forward contracts not designated as hedging instruments were $0.9 million for the year ended December 31, 2019. Losses on foreign currency forward contracts not designated as hedging instruments were $0.4 million for the year ended December 31, 2018.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets, which are generally two to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of the remaining lease term or their estimated useful lives. Repair and maintenance costs are charged to expense as incurred.
Internal-Use Software and Platform Development Costs	Internal-Use Software and Platform Development Costs The Company’s policy is to capitalize certain costs to develop its internal-use software and platform when (i) preliminary project planning is completed, (ii) the Company has committed project resourcing, and (iii) it is probable that the project will be completed and the software will be used as intended. Costs incurred for enhancements that are expected to result in additional significant functionality are also capitalized. Such costs are generally amortized on a straight-line basis over their estimated useful lives determined on a project-by-project basis, which historically has ranged between two to three years, beginning when the asset is ready for its intended use. Costs incurred prior to meeting these criteria, together with costs incurred for training and maintenance, are expensed as incurred. Amortization of capitalized internal-use software and platform development costs is allocated to functional expense categories based on headcount and the nature and intended use of the project.
Segment Information	Segment Information The Company has one reportable segment. The Company’s chief operating decision maker is its President and Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance.
Goodwill, Acquired Intangible Assets, and Other Long-Lived Assets	Goodwill, Acquired Intangible Assets, and Other Long-Lived Assets Goodwill represents the excess of the aggregate fair value of the consideration transferred over the fair value of the net tangible and identifiable intangible assets acquired in the Elance-oDesk Combination. Goodwill is not amortized, but rather is assessed for impairment at least annually, or more frequently if events and changes in circumstances indicate that its carrying amount may not be recoverable. The Company performs its annual impairment assessment during the fourth quarter of each calendar year based on a single reporting unit structure by comparing the carrying value of the reporting unit to its fair value. An impairment would occur if the carrying amount of a reporting unit exceeded the fair value of that reporting unit. There has been no impairment of goodwill for any of the periods presented. The Company’s long-lived assets consist of property and equipment and acquired identifiable, finite-lived intangible assets, namely developed technology, user relationships, trade names, and domain names. The finite-lived intangible assets are carried at cost, less accumulated amortization. The Company amortizes the finite-lived intangible assets over their estimated useful lives ranging from two to seven years based on the pattern in which the economic benefits of the intangible assets are consumed, or the straight-line method when the pattern cannot be reliably determined. The Company periodically reviews the remaining estimated useful lives of its long-lived tangible and amortizable intangible assets. If the estimated useful life assumption for any asset is changed, the remaining unamortized balance would be depreciated or amortized over the revised estimated useful life, on a prospective basis. Intangible amortization expense related to developed technology and trade names is recorded as cost of revenue. Intangible amortization expense related to user relationships and domain names is included in operating expenses. The Company evaluates the recoverability of its long-lived assets, including finite-lived intangible assets, for possible impairment whenever events or circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of these assets is measured by comparing the carrying amounts to the future undiscounted cash flows the assets are expected to generate. If it is determined that the asset group is not recoverable, an impairment loss is recorded in the amount by which the carrying amount of the asset group exceeds the aggregate future undiscounted cash flows. When an impairment loss is recognized, the carrying amount of such assets is reduced to fair value. For 2020, the Company conducted its goodwill impairment testing by performing the first step of the two-step impairment model. The fair value was determined by the Company using quoted market prices of the Company’s common stock. The Company determined that the fair value of its reporting unit exceeded the carrying value, and, as such, the Company concluded that there was no impairment of goodwill at the impairment testing date. There was no impairment of long-lived assets in any of the periods presented.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs, consisting of legal, accounting, and filing fees directly relating to the Company’s IPO, were capitalized and offset against the IPO proceeds upon the completion of the offering. Upon completion of the Company’s IPO, approximately $6.3 million of deferred offering costs were offset against the IPO proceeds in additional paid-in capital.
Revenue Recognition	Revenue Recognition The Company primarily generates revenue from clients from its marketplace and managed service offerings and from freelancers from its marketplace. The Company accounts for revenue in accordance with Financial Accounting Standards Board, which is referred to as FASB, Accounting Standards Update, which is referred to as ASU, No. 2014-09, Revenue from Contracts with Customers (Topic 606), which the Company adopted on December 31, 2019 effective as of January 1, 2019 using the modified retrospective method. Revenue is recognized upon transfer of control of promised services to users in an amount that reflects the consideration the Company expects to receive in exchange for those services. In the ordinary course of business, the Company makes payments to users when those users provide services in their capacity as vendors. These payments are for distinct services and are at fair value. These transactions are primarily with certain financial institutions that the Company uses as payment processors on the work marketplace. The Company accounts for the consideration payable to these users in their capacity as vendors as a purchase of services from a vendor and records such payments in either cost of revenue or sales and marketing within the consolidated statements of operations. Marketplace The Company’s marketplace revenue is derived from Upwork Basic, Plus, and Enterprise and other premium offerings. Upwork Basic and Plus The Company earns fees from freelancers under the Upwork Basic and Plus offerings, which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services (including, but not limited to, communication, invoicing, reporting, dispute resolution, and payment services) is substantially the same and the freelancer simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Basic and Plus offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. The Company’s Upwork Basic and Plus arrangements may include fixed and variable consideration, or a combination of the two, comprised of the following: Service fees. Freelancers are provided access to the Upwork work marketplace to market their businesses, send proposals to and communicate with prospective clients, and, if engaged by a client, to perform specified services agreed between freelancers and clients, which are referred to as freelancer services. Freelancers charge clients on an hourly or a milestone basis for services rendered to clients through the Upwork work marketplace, which are referred to as freelancer billings; billings charged on an hourly basis are variable consideration; and billings on a milestone basis represent fixed consideration. The Company charges freelancers a service fee as a percentage of freelancer billings using a tiered service fee model based on cumulative lifetime billings by the freelancer to each client. The arrangements subject to tiered service fees also include contract renewal options that represent a material right. The Company takes no responsibility for the freelancer services, and therefore, does not control the freelancer services. Additionally, freelancers and clients negotiate and agree upon the scope and the price for freelancer services directly with each other, and the Company is not a party to those agreements. Accordingly, for these tiered service fee arrangements, the Company presents revenue on a net basis, as an agent. The Company recognizes the service fee as services are rendered for each distinct time increment in the series. Withdrawal fees. The Company charges withdrawal fees to freelancers when the freelancers withdraw their escrow funds held by the Company. A withdrawal fee is charged for each withdrawal transaction, which represents variable consideration. The Company presents revenue from withdrawal fees on a gross basis as a principal and not net of the third-party payment processing costs incurred because the Company controls the payment processing services prior to providing to the Company's freelancers. The Company recognizes the withdrawal fees when transactions are processed for each distinct time increment in the series. Membership fees. The Company charges membership fees to freelancers. These fees are fixed consideration and are charged monthly. The Company recognizes the revenue over the period of the membership consistent with the common measure of progress for the entire performance obligation. Connects fees. The Company charges fees to freelancers for the purchase of Connects, which are virtual tokens that are required for freelancers to bid on projects on the Company’s work marketplace. These fees represent variable consideration, and the Company recognizes revenue as Connects are used in each distinct time increment in the series. The Company earns fees from clients under the Upwork Basic and Plus offerings, which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services is substantially the same and the client simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Basic and Plus offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. The Company’s Upwork Basic and Plus arrangements may include fixed and variable consideration, or a combination of the two, comprised of the following: Client payment processing and administration fees. The Company charges clients for payment processing services at the time the client is charged for the amounts due from the client. This fee is charged on a per-transaction basis and is variable consideration. Per-transaction payment processing fees are recognized when the client is charged for the amount due and fees charged on a monthly basis are recognized over the month that payment processing services are provided. For client payment processing fees, the Company presents revenue on a gross basis as a principal and not net of the third-party payment processing costs incurred because the Company controls the payment processing and administration services prior to providing to the Company’s clients. The Company recognizes the revenue when a payment from a client is processed in each distinct time increment in the series. Foreign currency exchange fees. The Company charges clients a fixed mark-up above foreign currency exchange rates that are charged to the Company when the Company collects amounts denominated in foreign currency. Foreign currency exchange fees are variable consideration and recognized as they are earned for each transaction processed in each distinct time increment in the series. Membership fees. The Company charges membership fees to clients. These fees are charged monthly, are fixed consideration, and are recognized over the period of the membership, which is generally monthly consistent with the common measure of progress for the entire performance obligation. Upwork Payroll service fees. The Company charges clients using the Upwork Payroll offering when their freelancers are classified as employees for engagements on the Upwork work marketplace. The client enters into an Upwork Payroll agreement with the Company, and Upwork separately contracts with unrelated third-party staffing providers that provide employment services to such clients. In such arrangements, freelancers providing freelancer services to clients become employees of third-party staffing providers. In arrangements where clients enter into Upwork Payroll agreements, the Company charges Upwork Payroll service fees to clients and does not charge service fees to the freelancers who are employees of the third-party staffing providers. Such service fees are variable consideration and charged as a fixed percentage of the total freelancer billings. Under an Upwork Payroll agreement, the Company provides the client access to the Upwork work marketplace to procure and manage freelancer services, as well as access to employment services provided by the third-party staffing providers. The Company presents Upwork Payroll service fees revenue on a net basis as an agent of the client for providing access to employment services provided by the third-party staffing provider. The Company does not control these employment services performed by the third-party on behalf of the client or for the services performed by the freelancers that are employed by the third-party staffing provider. Therefore, the Company is not considered the principal for these services. The Company recognizes the Upwork payroll service fee as revenue as the services are provided for each distinct time increment in the series. Upwork Enterprise and Other Premium Offerings The Company earns fees from freelancers under Upwork Enterprise and other premium offerings, which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services is substantially the same and the freelancer simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Enterprise and other premium offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. These arrangements include variable consideration as follows: Service fees. The Company provides freelancers access to the Upwork work marketplace to perform freelancer services for clients. The Company charges freelancers a service fee as a percentage of freelancer billings. The Company earns service fees based on a fixed percentage of freelancer billings. For service fees charged to freelancers, the Company presents revenue on a net basis, as an agent, for providing access to the Upwork work marketplace as it does not control the freelancer services provided to clients, and therefore the Company is not considered the principal for the freelancer services. Additionally, freelancers and clients negotiate and agree upon the scope and the price for freelancer services directly with each other, and the Company is not a party to their agreement. The Company recognizes the service fee as services are rendered for each distinct time increment in the series. The Company earns fees from clients under Upwork Enterprise and other premium offerings, each of which represent a single promise to provide continuous access (i.e. stand-ready performance obligation) to the Company’s work marketplace and site services. As each day of providing access to the work marketplace and site services is substantially the same and the client simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its Upwork Enterprise and other premium offerings is comprised of a series of distinct service periods. The Company allocates variable consideration received to each distinct service period within the series and recognizes revenue as each distinct service period is performed. These arrangements may include fixed and variable consideration, or a combination of the two, comprised of the following: Client service fees. The Company offers clients access to the Company’s work marketplace to source freelancers in exchange for a client service fee calculated as a percentage of freelancer billings; these fees represent variable consideration. The Company recognizes the service fee as services are rendered for each distinct time increment in the series. Enterprise compliance service fees. The Company charges fees to its enterprise compliance service clients that engage the Company to provide services to determine whether a freelancer should be classified as an employee or an independent contractor based on the scope of freelancer services agreed between the client and freelancer and other factors. The Company charges enterprise compliance service fees as a percentage of freelancer billings; these fees represent variable consideration. The Company recognizes the compliance service fee as services are rendered for each distinct time increment in the series. Subscription fees. The Company charges monthly or annual subscription fees to clients for subscription services. These subscription fees are fixed consideration and are recognized over the period of the subscription consistent with the common measure of progress for the entire performance obligation. Upwork Payroll service fees. Upwork Payroll service fees are recognized on the same basis as described under the Upwork Basic and Plus offerings and are variable consideration. Revenue sharing arrangements Certain of the Company’s offerings include revenue sharing arrangements under which the Company generates a revenue share as a percentage of the fees charged by certain financial institutions to the freelancers for payment withdrawals. These arrangements are considered a single performance obligation comprised of variable consideration and are recognized over time based on transactions processed. Managed Services Under a managed services arrangement, the Company is responsible for providing services and engaging freelancers directly or as employees of third-party staffing providers to perform the services for clients on the Company’s behalf. These arrangements are generally time- and materials-based, and are invoiced on a monthly basis. These fees represent variable consideration. The Company controls and directs the services performed on behalf of the freelancers and presents revenue on a gross basis as principal. As each day of providing managed services is substantially the same and the client simultaneously receives and consumes the benefits as services are provided, the Company’s single promise under its managed services is comprised of a series of distinct service periods. For managed services arrangements with clients, the Company allocates the variable amounts to each distinct service period within the series and recognizes revenue as each distinct service period is performed. Arrangements with Multiple Performance Obligations Certain of the Company’s contracts with freelancers contain multiple performance obligations in the event the Company determines a material right exists. Specifically, the arrangements with freelancers subject to tiered service fees include contract renewal options that represent a material right. For such arrangements, the Company allocates revenue to each performance obligation based on its relative standalone selling price by applying the portfolio approach practical expedient under Topic 606. Standalone selling prices for offerings subject to tiered service fees are estimated based on observable transactions when these services are sold on a standalone basis. Standalone selling price for a material right is estimated by determining the discount that the freelancer would obtain when exercising the option, adjusted for the likelihood that the option will be exercised. Significant judgment is applied in the application of the portfolio approach practical expedient, which includes estimating the standalone selling price of the material rights and the period of time over which to defer and recognize the consideration allocated to the material rights. Specifically, management applied significant judgment in assessing the appropriateness of the model for the estimates, which include assessing the appropriateness of the methodology and relevant data inputs to (i) estimate the standalone selling price of the material rights, which includes the standalone selling price of the services when sold separately and the likelihood of exercise of the material rights; and (ii) estimate the period of time over which to defer and recognize the consideration allocated to the material rights. The Company utilized historical user transaction data in developing the estimates. The Company recognizes revenue related to the material rights based on the Company’s estimate of when the material rights are exercised and adjusts revenue for changes in estimates in the period of change on a cumulative catch-up basis. Deferred Revenue Deferred revenue consists of subscription, membership, and Connects fees collected in advance of performing the service. The Company also recognizes deferred revenue for amounts attributable to unexercised material rights related to arrangements with freelancers that are subject to tiered service fees.
Cost of Revenue	Cost of Revenue Cost of revenue consists primarily of the cost of payment processing fees, costs of freelancers to deliver services under the Company’s managed services offering, personnel-related costs for the Company’s services and support personnel, third-party hosting fees, and amortization expense associated with acquired intangibles and capitalized internal-use software. The Company defines personnel-related costs as salaries, bonuses, benefits, and stock-based compensation costs for employees, and costs related to other service providers the Company engages to provide internal services to the Company.
Research and Development	Research and Development Research and development expense primarily consists of personnel-related costs and third-party hosting costs related to development. Research and development costs are expensed as incurred, except to the extent that such costs are associated with internal-use software and platform development that qualify for capitalization.
Advertising Expense	Advertising ExpenseThe Company expenses advertising costs as incurred.
Provisions for Transactions Losses	Provision for Transaction Losses Provision for transaction losses consists primarily of losses resulting from fraud on the work marketplace and bad debt expense associated with the Company’s trade and client receivables balance and transaction losses expense related to chargebacks. Provision for these items represent estimates of losses based on the Company’s actual historical incurred losses and other factors.
Redeemable Convertible Preferred Stock Warrant Liability	Redeemable Convertible Preferred Stock Warrant Liability The Company accounts for freestanding warrants to purchase shares of its redeemable convertible preferred stock as a liability as the underlying shares of convertible preferred stock are contingently redeemable and, therefore, may obligate the Company to transfer assets at some point in the future. The redeemable convertible preferred stock warrants are recorded as other liabilities, noncurrent in the consolidated balance sheets at their estimated fair values and are subject to remeasurement at each balance sheet date. Any change in fair value from remeasurement is recognized as a component of other (income) expense, net in the consolidated statements of operations. The Company adjusted the liability for changes in fair value through the completion of its IPO in October 2018, at which time the outstanding redeemable convertible preferred stock warrant converted to a common stock warrant and was reclassified to additional paid-in capital.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock options, restricted stock units, which are referred to as RSUs, and purchase rights granted under the 2018 Employee Stock Purchase Plan, which is referred to as the 2018 ESPP, to employees and directors based on their estimated fair value on the date of grant. The fair value of each stock option and purchase rights granted under the 2018 ESPP is estimated using the Black-Scholes valuation model. The model requires the Company to make a number of assumptions, including the value of the Company’s common stock, expected volatility, expected term, risk-free interest rate, and expected dividends. The Company evaluates the assumptions used to value option awards upon each grant of stock options. The fair value of RSUs awarded to employees is based on the closing price of the Company’s common stock, as reported on The Nasdaq Global Select Market on the date of grant. The Company generally recognizes stock-based compensation expense for stock options and RSUs on a straight-line basis over the vesting term. Stock-based compensation for purchase rights granted under the 2018 ESPP is recognized over the offering period. The Company accounts for forfeitures as they occur.
Foreign Currency	Foreign CurrencyThe functional currency of the Company and its subsidiaries is the U.S. dollar. Transactions with users denominated in currencies other than the U.S. dollar are remeasured at the exchange rate in effect on the date of the transaction. At the end of each reporting period, monetary assets and liabilities are remeasured using exchange rates in effect at the balance sheet date. Foreign currency transaction gains and losses are included in other (income) expense, net in the consolidated statements of operations.
Comprehensive Loss	Comprehensive Loss For the year ended December 31, 2020, net unrealized losses from the Company’s marketable securities were immaterial. Comprehensive loss approximates net loss for all periods presented. Accordingly, the consolidated statements of comprehensive loss have been omitted from the consolidated financial statements.
Income Taxes	Income Taxes The Company accounts for income taxes in accordance with the liability method. Under the liability method, deferred assets and liabilities are recognized based upon anticipated future tax consequences attributable to differences between financial statement carrying amounts of assets and liabilities and their respective tax bases. The provision for income taxes is comprised of the current tax liability and the change in deferred tax assets and liabilities. The Company establishes a valuation allowance to the extent that it is more likely than not that deferred tax assets will not be recoverable against future taxable income. Deferred tax assets and liabilities are measured using the enacted tax rates that will be in effect for the years in which those tax assets are expected to be realized or settled. The Company regularly assesses the likelihood that its deferred tax assets will be realized from recoverable income taxes or recovered from future taxable income based on the realization criteria set forth in the relevant authoritative guidance. To the extent that the Company believes any amounts are not more likely than not to be realized, the Company records a valuation allowance to reduce its deferred tax assets. The realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. If the Company subsequently realizes deferred tax assets that were previously determined to be unrealizable, the respective valuation allowance would be reversed, resulting in an adjustment to earnings in the period such determination is made. In addition, the calculation of tax liabilities involved dealing with uncertainties in the application of complex tax regulations. The Company recognized potential liabilities based on its estimate of whether, and the extent to which, additional taxes will be due. The Company accounts for uncertain tax positions in accordance with the relevant guidance, which prescribes a recognition threshold and measurement approach for uncertain tax positions taken or expected to be taken in a company’s income tax return, and also provides guidance on recognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition. The guidance utilized a two-step approach for evaluation uncertain tax positions. Step one, Recognition, requires a company to determine if the weight of available evidence indicates a tax position is more likely than not to be sustained upon audit. Step two, Measurement, is based on the largest amount of benefit, which is more likely than not to be realized on ultimate settlement. A liability is reported for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. Any interest and penalties related to unrecognized tax benefits are recorded as income tax expense.
Net Loss per Share	Net Loss per Share Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss is computed by adjusting net loss to reallocate undistributed earnings based on the potential impact of dilutive securities, including outstanding common stock options, RSUs, warrants to purchase common stock, and common stock issuable in connection with the 2018 ESPP. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share because dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Recent Accounting Pronouncements Not Yet Adopted and Recently Adopted Accounting Pronouncements	Recent Accounting Pronouncements Not Yet Adopted The Company has reviewed all recently issued accounting pronouncements and concluded they were either not applicable or not expected to have a material impact on the Company’s consolidated financial statements. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016–13, Financial Instruments—Credit Losses (Topic 326). This standard changes the methodology for measuring credit losses on financial instruments and the timing of when such losses are recorded. In April 2019, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments. The amendments in this update represent changes to clarify, correct errors in, or improve the Codification. In May 2019, the FASB issued ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326). The amendments in this update provide entities that have certain instruments within the scope of Subtopic 326-20, Financial Instruments—Credit Losses—Measured at Amortized Cost, with an option to irrevocably elect the fair value option in Subtopic 825-10, Financial Instruments—Overall, applied on an instrument-by-instrument basis for eligible instruments, upon adoption of Topic 326. This guidance is effective January 1, 2020 with early adoption permitted. The standard requires a modified retrospective method of adoption. The Company adopted ASU No. 2016-13 and related updates on January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Others (Topic 350): Simplifying the Test for Goodwill Impairment. ASU No. 2017-04 eliminates Step 2 from the goodwill impairment test, which measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. Under ASU No. 2017-04, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of the reporting unit with its carrying amount and recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the loss not exceeding the total amount of goodwill allocated to that reporting unit. The guidance becomes effective for the Company on January 1, 2020 on a prospective basis for its annual or any interim goodwill impairment tests during the 2020 fiscal year. The Company adopted ASU No. 2017-04 on January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement, which modifies the disclosure requirements on fair value measurements. ASU No. 2018-13 is effective for the Company beginning January 1, 2020. The Company adopted ASU No. 2018-13 on January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (“Subtopic 350-40”): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. ASU No. 2018-15 aligns the requirements for capitalizing implementation costs in a cloud computing arrangement service contract with the requirements for capitalizing implementation costs incurred for an internal-use software license. ASU No. 2018-15 is effective for the Company beginning January 1, 2020. The Company adopted ASU No. 2018-15 on January 1, 2020 using the prospective adoption method. The adoption did not have a material impact on the Company’s consolidated financial statements.

Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Schedule of Cash and Cash Equivalents


	2020		2019		2018
Cash and cash equivalents	$	94,081	$	48,392	$	129,128
Restricted cash	3,340		2,490		2,753
Funds held in escrow, including funds in transit	135,042		108,721		98,186
Total cash, cash equivalents, and restricted cash as shown in the consolidated statement of cash flows	$	232,463	$	159,603	$	230,067

Schedule of allowance for doubtful accounts

The following table presents the changes in the allowance for doubtful accounts as of December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Allowance for doubtful accounts, beginning balance	$	2,215	$	2,832	$	1,577
Provision for doubtful accounts	3,143		3,193		4,940
Amounts written off	(3,697)		(3,810)		(3,685)
Allowance for doubtful accounts, ending balance	$	1,661	$	2,215	$	2,832

Revenue (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Contract balances


	2020		2019
Trade and client receivables, net of allowance	$	47,018	$	30,156
Contract liabilities
Deferred revenue	16,801		13,799
Deferred revenue (component of other liabilities, noncurrent)	4,177		3,153

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Financial Instruments Measured at Fair Value on a Recurring Basis

The following tables set forth the fair value of the Company’s financial assets measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands):


	December 31, 2020
	Level I		Level II		Level III		Total

Cash equivalents
Money market funds	$	65,723	$	—	$	—	$	65,723
Commercial paper	—		5,999		—		5,999
Marketable securities
Commercial paper	—		50,965		—		50,965
Treasury Bills	4,499		—		—		4,499
U.S. government securities	20,106		—		—		20,106
Total financial assets	$	90,328	$	56,964	$	—	$	147,292


	December 31, 2019
	Level I		Level II		Level III		Total

Cash equivalents—money market funds	$	35,286	$	—	$	—	$	35,286
Marketable securities
Commercial paper	—		50,794		—		50,794
U.S. government securities	34,687		—		—		34,687
Total financial assets	$	69,973	$	50,794	$	—	$	120,767

Summary of Changes in Fair Value of Redeemable Convertible Preferred Stock Warrants

The following table sets forth a summary of the changes in the fair value of the redeemable convertible preferred stock warrant liability (in thousands):







Fair value at December 31, 2017	$	1,104
Change in fair value	6,056
Conversion to common stock warrant in connection with the initial public offering	(7,160)
Fair value at December 31, 2018	$	—

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2020

Balance Sheet Related Disclosures [Abstract]

Property and Equipment, Net

Property and equipment, net consisted of the following as of December 31, 2020 and 2019 (in thousands):


	2020		2019
Computer equipment and software	$	4,819	$	3,613
Internal-use software and platform development costs	20,727		12,726
Leasehold improvements	14,613		10,576
Office furniture and fixtures	3,354		2,454
Total property and equipment	43,513		29,369
Less: Accumulated depreciation	(15,374)		(7,915)
Property and equipment, net	$	28,139	$	21,454

Schedule of Finite Lived Intangible Assets

All of the Company’s identifiable intangible assets were acquired in March 2014 from the Elance-oDesk Combination. Intangible assets, net consisted of the following (in thousands):


	As of December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trade names	$	2,293	$	2,293	$	—
User relationships	18,678		18,011		667
Developed technology	10,356		10,356		—
Domain names	529		529		—
Total	$	31,856	$	31,189	$	667


	As of December 31, 2019
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trade names	$	2,293	$	2,293	$	—
User relationships	18,678		15,343		3,335
Developed technology	10,356		10,356		—
Domain names	529		529		—
Total	$	31,856	$	28,521	$	3,335

Schedule of Indefinite-Lived Intangible Assets

All of the Company’s identifiable intangible assets were acquired in March 2014 from the Elance-oDesk Combination. Intangible assets, net consisted of the following (in thousands):


	As of December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trade names	$	2,293	$	2,293	$	—
User relationships	18,678		18,011		667
Developed technology	10,356		10,356		—
Domain names	529		529		—
Total	$	31,856	$	31,189	$	667


	As of December 31, 2019
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trade names	$	2,293	$	2,293	$	—
User relationships	18,678		15,343		3,335
Developed technology	10,356		10,356		—
Domain names	529		529		—
Total	$	31,856	$	28,521	$	3,335

Estimated Future Amortization Expense for Acquired Intangible Assets

As of December 31, 2020, the estimated future amortization expense for the acquired intangible assets is as follows (in thousands):


Year Ended December 31,	Estimated Amortization Expense
2021	$	667


Total	$	667

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following as of December 31, 2020 and 2019 (in thousands):


	2020		2019
Accrued compensation and related benefits	$	14,007	$	5,344
Accrued freelancer costs	1,235		622
Accrued indirect taxes	3,818		2,401
Accrued vendor expenses	8,662		5,485
Accrued payment processing fees	1,219		832
Operating lease liability, current	3,725		3,214
Other	202		444
Total accrued expenses and other current liabilities	$	32,868	$	18,342

Assets And Liabilities, Lessee

The following table summarizes the Company’s operating lease assets and lease liabilities as of December 31, 2020 and 2019 (in thousands):


Balance Sheet Classification		2020		2019
Assets
Operating—noncurrent	Operating lease asset	$	19,729	$	21,908
Liabilities
Operating—current	Accrued expenses and other current liabilities	3,725		3,214
Operating—noncurrent	Operating lease liability, noncurrent	20,506		21,186
Total lease liabilities		$	24,231	$	24,400

Lessee, Operating Lease, Liability, Maturity

The following table shows the Company’s future lease commitments due in each of the next five years and thereafter for operating leases (in thousands):


Year Ended December 31,	Leases
2021	$	3,919
2022	5,391
2023	6,519
2024	5,843
2025	2,356
Thereafter	4,937

Total lease payments	28,965
Adjustment for discount to present value	(4,734)
Total	$	24,231

Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Summary of Carrying Value of Debt

The following table presents the carrying value of the Company’s debt obligations as of December 31, 2020 and 2019 (in thousands):


	2020			2019
First term loan—18 months of interest-only payments ended in March 2019 followed by 36 equal monthly installments of principal plus interest, maturing March 2022; interest at prime plus 0.25% per annum	$	6,250		$	11,250
Second term loan—17 months of interest-only payments ended in March 2019 followed by 42 equal monthly installments of principal plus interest, maturing September 2022; interest at prime plus 0.25% per annum	4,500			7,071

Total debt	10,750			18,321
Less: Unamortized debt discount issuance costs	(27)			(38)
Balance	10,723			18,283
Debt, current	(7,581)			(7,584)
Debt, noncurrent	$	3,142		$	10,699
Weighted-average interest rate	5.64		%	6.93		%

Schedule of Maturities of Long-term Debt

Future maturities of principal payments, excluding potential early payments, as of December 31, 2020, were expected to be as follows (in thousands):


Year Ended December 31,	Principal Payments
2021	$	7,571
2022	3,179




Total	$	10,750

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

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+ Details

Preferred and Common Stock Warrants (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Assumptions Used to Calculate Fair Value of Outstanding Warrants

The following assumptions were used to calculate the estimated fair value of the then-outstanding warrants until the closing date of the Company’s IPO:



Dividend yield	0	%
Expected term (in years)	2.75
Risk-free interest rates	1.8	%
Expected volatility	34.6	%

Preferred and Common Stock (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Summary of Common Stock Shares Reserved for Future Issuance

As of December 31, 2020 and 2019, the Company had reserved shares of common stock for future issuance as follows:


	2020	2019
Options issued and outstanding	4,858,590	15,140,579
RSUs issued and outstanding	5,568,225	2,503,182

Warrant to purchase common stock	400,000	450,000


Remaining shares reserved for future issuances under 2018 Equity Incentive Plan	18,332,765	16,091,801
Remaining shares reserved for future issuances under 2018 Employee Stock Purchase Plan	2,419,154	1,994,971
Total	31,578,734	36,180,533

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

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+ Details

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Summary of Fair Value Assumptions on Stock Options Granted

The fair values of the awards modified by the Transition Agreement were estimated using the Black-Scholes valuation model with the following assumptions:


Dividend yield	—	%
Expected term (in years)	0.3 - 1.3
Risk-free interest rates	1.5% - 1.6%
Expected volatility	38% - 39%

For the year ended December 31, 2018, the fair value of stock options granted to employees was estimated on the grant date using the Black-Scholes valuation model with the following assumptions:



Dividend yield	—	%
Expected term (in years)	5.2 - 6.1
Risk-free interest rates	2.5% - 2.9%
Expected volatility	38% - 45%

Summary of Activity under Stock Option Plans

The following table summarizes activity under the Company’s stock option plans:


	Number of Shares Underlying Outstanding Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)








Balances at December 31, 2019	15,140,579	$	3.61	6.19	$	106,967

Exercised	(9,065,976)	3.42
Forfeited and canceled	(1,216,013)	4.08
Balances at December 31, 2020	4,858,590	3.83		5.80	149,046
Vested and exercisable as of December 31, 2020	3,876,252	3.74		5.55	119,303
Vested and expected to vest as of December 31, 2020	4,858,590	3.83		5.80	149,046

Summary of Activity under RSU Plans

The following table summarizes the RSU activity and related information under the 2018 EIP:


	Number of RSUs Outstanding	Weighted-Average Grant Date Fair Value
Unvested balance - January 1, 2020	2,503,182	$	15.82
Granted	5,750,034	10.96
Vested	(1,590,225)	13.15
Forfeited/canceled	(1,094,766)	12.70
Unvested balance - December 31, 2020	5,568,225	$	12.20

Summary of Fair Value Assumptions on Employee Stock Purchas Plans


	2020	2019	2018
Dividend yield	0%	0%	0%
Expected term (in years)	0.5 - 2.0	0.5 - 2.0	0.5 - 2.0
Risk-free interest rates	0.1% - 0.2%	1.5% - 2.4%	2.4% - 2.9%
Expected volatility	50% - 82%	38% - 47%	37%

Summary of Components of Stock-Based Compensation Expense Recognized


	2020		2019		2018
Cost of revenue	$	779	$	456	$	282
Research and development	9,783		6,471		3,258
Sales and marketing	4,440		2,609		1,637
General and administrative	10,506		9,262		5,184
Total	$	25,508	$	18,798	$	10,361

Net Loss per Share (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders


	2020		2019		2018
Numerator:
Net loss	$	(22,867)	$	(16,659)	$	(19,907)



Denominator:
Weighted-average shares used to compute net loss per share, basic and diluted	118,698,567		109,814,604		52,327,518
Net loss per share, basic and diluted	$	(0.19)	$	(0.15)	$	(0.38)

Schedule of Potentially Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders


	2020	2019	2018
Options to purchase common stock	4,858,590	15,140,579	23,774,279

Common stock issuable upon exercise of common stock warrants	400,000	450,000	898,331

Common stock issuable upon vesting of restricted stock units	5,568,225	2,503,182	288,460
Common stock issuable in connection with employee stock purchase plan	540,580	1,651,263	—
Total	11,367,395	19,745,024	24,961,070

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax

For the years ended December 31, 2020, 2019, and 2018, the loss before income taxes consisted of the following (in thousands):


	2020		2019		2018
Domestic	$	(22,748)	$	(16,658)	$	(19,925)
Foreign	31		27		33
Total loss before income taxes	$	(22,717)	$	(16,631)	$	(19,892)

Schedule of Components of Income Tax Expense

For the years ended December 31, 2020, 2019, and 2018, the components of the income tax provision were as follows (in thousands):


	2020		2019		2018
Current:
Federal	$	(19)	$	—	$	—
State	(127)		(26)		(11)
Foreign	(4)		(2)		(4)
Total current	$	(150)	$	(28)	$	(15)
Deferred:
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	—		—		—
Total deferred	$	—	$	—	$	—
Total income tax benefit (provision)	$	(150)	$	(28)	$	(15)

Schedule of Effective Income Tax Rate Reconciliation

The reconciliation of the statutory federal income tax rate to the Company’s effective tax rate for the years ended December 31, 2020, 2019, and 2018 were as follows:


	2020		2019		2018
Tax at federal statutory rate	21.00	%	21.00	%	21.00	%
State tax, net of federal benefit	(0.49)		(0.27)		1.88
Stock-based compensation	94.02		51.45		(5.84)
Warrant expense	—		—		(6.98)
Other items	(0.59)		(4.34)		(1.46)
Research and development credits	9.74		13.74		10.54
Net operating loss expiration	(14.00)		(18.33)		—
Change in valuation allowance	(110.34)		(63.42)		(19.21)
Effective tax rate	(0.66)	%	(0.17)	%	(0.07)	%

Schedule of Deferred Tax Assets and Liabilities

As of December 31, 2020 and 2019, the significant components of the Company’s deferred tax assets and liabilities were as follows (in thousands):


	2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	77,230	$	48,988
Stock-based compensation	230		4,192
Operating lease liability	5,555		10,248
Non-deductible accrued expenses, reserves and other	4,903		2,596
Research and development credits	11,352		8,762
Gross deferred tax assets	99,270		74,786
Valuation allowance	(92,390)		(63,542)
Total deferred tax assets	6,880		11,244
Deferred tax liabilities:
Acquired intangible assets	(89)		(693)
Operating lease asset	(4,523)		(9,202)
Depreciation and amortization	(2,268)		(1,349)
Total deferred tax liabilities	(6,880)		(11,244)
Net deferred tax assets	$	—	$	—

Summary of Valuation Allowance

The change in valuation allowance for deferred tax assets was as follows for the periods presented (in thousands):


Year Ended December 31,	Balance at Beginning of Year		Additions Charged to Costs & Expenses		Additions Charged to Other Accounts		Deductions		Balance at End of Year

2020	$	63,542	$	28,848	$	—	$	—	$	92,390
2019	49,439		14,103		—		—		63,542
2018	45,364		4,075		—		—		49,439

Summary of Unrecognized Tax Benefits

For the years ended December 31, 2020, 2019, and 2018, the activity related to the unrecognized tax benefits were as follows (in thousands):


	2020		2019		2018
Gross unrecognized tax benefits—beginning balance	$	12,782	$	10,973	$	10,200
Increase related to tax positions taken during prior year	131		—		108
Decrease related to tax positions taken during prior year	—		(164)		(2)
Increase related to tax positions taken during current year	608		1,973		667
Decrease related to tax positions taken during current year	—		—		—
Decrease related to expiration of unrecognized tax benefit	(183)		—		—
Gross unrecognized tax benefits—ending balance	$	13,338	$	12,782	$	10,973

Segment and Geographical Information (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Revenue by Type of Service

The following table sets forth total revenue by type of service for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Marketplace	$	338,152	$	268,284	$	223,831
Managed services	35,476		32,278		29,523
Total	$	373,628	$	300,562	$	253,354

Revenue by Geographic Area Based on Billing Address of Freelancers and Clients

The following table sets forth total revenue by geographic area based on the billing address of its freelancers and clients for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	2020		2019		2018
Freelancers:
United States	$	60,861	$	50,154	$	40,313
India	33,109		27,369		25,485
Philippines	22,924		19,660		17,057
Rest of world	109,805		90,259		80,387
Total freelancers	226,699		187,442		163,242
Clients:
United States	107,359		87,241		65,578
Rest of world	39,570		25,879		24,534
Total clients	146,929		113,120		90,112
Total	$	373,628	$	300,562	$	253,354

Organization and Description of Business (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2015 platform
Subsidiary, Sale of Stock [Line Items]
Number of operating platforms consolidated \| platform		2
Consideration received on stock transaction \| $	$ 109.4
IPO
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in stock transaction (in shares) \| shares	7,840,908
Price per share of stock transaction (in dollars per share) \| $ / shares	$ 15.00
Underwriters' Option
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in stock transaction (in shares) \| shares	1,022,727
Price per share of stock transaction (in dollars per share) \| $ / shares	$ 1.05

Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)
Subsidiary, Sale of Stock [Line Items]
Restricted cash	$ 3,340,000	$ 2,490,000	$ 2,753,000
Restricted cash, current	2,300,000	1,700,000
Restricted cash, noncurrent	1,000,000.0	800,000
Escrow funds payable	$ 135,042,000	$ 108,721,000
Number of Clients \| segment	3	2
Revenue	$ 373,628,000	$ 300,562,000	253,354,000
Gross trade receivables	15,900,000	10,300,000
Gross client receivables	32,800,000	22,100,000
Capitalized costs	8,000,000.0	6,400,000	4,000,000.0
Internal-use software and platform development costs capitalized, amortization expense	$ 3,900,000	1,200,000	100,000
Number of reportable segments \| segment	1
Goodwill impairment	$ 0
Deferred offering costs		6,300,000
Advertising expense	51,400,000	37,400,000	23,600,000
Foreign currency transactions gain (loss)	(600,000)	900,000	(400,000)
Deferred revenue	16,801,000	13,799,000
Accumulated deficit	(194,824,000)	(171,957,000)
Operating lease asset	19,729,000	21,908,000
Operating lease liabilities	$ 24,231,000	24,400,000
Minimum
Subsidiary, Sale of Stock [Line Items]
Property and equipment, useful lives	2 years
Capitalized costs, amortization period	2 years
Intangible asset, useful life	2 years
Maximum
Subsidiary, Sale of Stock [Line Items]
Property and equipment, useful lives	5 years
Capitalized costs, amortization period	3 years
Intangible asset, useful life	7 years
Foreign Currency Forward Contracts
Subsidiary, Sale of Stock [Line Items]
Derivative, notional amount	$ 7,600,000	5,400,000
Gain (loss) on derivatives	$ (600,000)	900,000	(400,000)
Client Accounting For More than 10% revenue
Subsidiary, Sale of Stock [Line Items]
Revenue		$ 32,000,000.0	$ 29,500,000

Basis of Presentation and Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for doubtful accounts, beginning balance	$ 2,215	$ 2,832	$ 1,577
Provision for doubtful accounts	3,143	3,193	4,940
Amounts written off	(3,697)	(3,810)	(3,685)
Allowance for doubtful accounts, ending balance	$ 1,661	$ 2,215	$ 2,832

Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 94,081	$ 48,392	$ 129,128
Restricted cash	3,340	2,490	2,753
Funds held in escrow, including funds in transit	135,042	108,721	98,186
Total cash, cash equivalents, and restricted cash as shown in the consolidated statement of cash flows	$ 232,463	$ 159,603	$ 230,067	$ 111,099

Revenue - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Remaining performance obligation, amount	$ 21.0
Revenue recognized	13.0	$ 10.1
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, amount	21.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation, amount	$ 16.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, amount	$ 16.8

Revenue - Contract Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Trade and client receivables, net of allowance	$ 47,018	$ 30,156
Deferred revenue	16,801	13,799
Deferred revenue (component of other liabilities, noncurrent)	4,177	$ 3,153
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Trade and client receivables, net of allowance	$ 47,018

Fair Value Measurements - Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financial Assets:
Total financial assets	$ 147,292	$ 120,767
Level I
Financial Assets:
Total financial assets	90,328	69,973
Level II
Financial Assets:
Total financial assets	56,964	50,794
Level III
Financial Assets:
Total financial assets	0	0
Money market funds
Financial Assets:
Cash equivalents	65,723
Total financial assets		35,286
Money market funds \| Level I
Financial Assets:
Cash equivalents	65,723
Total financial assets		35,286
Money market funds \| Level II
Financial Assets:
Cash equivalents	0
Total financial assets		0
Money market funds \| Level III
Financial Assets:
Cash equivalents	0
Total financial assets		0
Commercial paper
Financial Assets:
Cash equivalents	5,999
Total financial assets	50,965	50,794
Commercial paper \| Level I
Financial Assets:
Cash equivalents	0
Total financial assets	0	0
Commercial paper \| Level II
Financial Assets:
Cash equivalents	5,999
Total financial assets	50,965	50,794
Commercial paper \| Level III
Financial Assets:
Cash equivalents	0
Total financial assets	0	0
Treasury Bills
Financial Assets:
Total financial assets	4,499
Treasury Bills \| Level I
Financial Assets:
Total financial assets	4,499
Treasury Bills \| Level II
Financial Assets:
Total financial assets	0
Treasury Bills \| Level III
Financial Assets:
Total financial assets	0
U.S. government securities
Financial Assets:
Total financial assets	20,106	34,687
U.S. government securities \| Level I
Financial Assets:
Total financial assets	20,106	34,687
U.S. government securities \| Level II
Financial Assets:
Total financial assets	0	0
U.S. government securities \| Level III
Financial Assets:
Total financial assets	$ 0	$ 0

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt obligations outstanding	$ 10,750	$ 18,321
Other (income) expense, net	$ (469)	$ (3,407)	$ 6,142
Cash equivalents—money market funds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other (income) expense, net			$ 6,100

Fair Value Measurements - Redeemable Convertible Preferred Stock Warrants (Details) - Cash equivalents—money market funds $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 1,104
Change in fair value	6,056
Conversion to common stock warrant in connection with the initial public offering	(7,160)
Fair value, ending balance	$ 0

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 43,513	$ 29,369
Less: Accumulated depreciation	(15,374)	(7,915)
Property and equipment, net	28,139	21,454
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	4,819	3,613
Internal-use software and platform development costs
Property, Plant and Equipment [Line Items]
Total property and equipment	20,727	12,726
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	14,613	10,576
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,354	$ 2,454

Balance Sheet Components - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 3,600,000	$ 2,800,000	$ 2,200,000
Capitalized costs	8,000,000.0	6,400,000	4,000,000.0
Internal-use software and platform development costs capitalized, amortization expense	3,900,000	1,200,000	100,000
Cost of Revenue	2,900,000	900,000
Amortization of intangible assets	2,700,000	2,700,000	$ 2,700,000
Operating lease cost	6,000,000.0	5,900,000
Sublease income	300,000	400,000
Variable lease cost	700,000	600,000
Operating lease payments	3,300,000	3,300,000
Operating lease asset	19,729,000	21,908,000
Operating lease liabilities	24,231,000	$ 24,400,000
Total minimum lease payments	$ 28,965,000
Long-term purchase commitment, period	5 years
Weighted average remaining lease term	5 years 4 months 24 days
Operating lease, weighted average discount rate	5.80%
Office Floor
Property, Plant and Equipment [Line Items]
Operating lease, term	5 years
Operating lease asset				$ 1,700,000
Operating lease liabilities				$ 1,700,000
Total minimum lease payments	$ 2,100,000
Minimum
Property, Plant and Equipment [Line Items]
Intangible asset, useful life	2 years
Operating lease, term	1 year
Maximum
Property, Plant and Equipment [Line Items]
Intangible asset, useful life	7 years
Operating lease, term	8 years
User relationships
Property, Plant and Equipment [Line Items]
Intangible asset, useful life	3 months 18 days

Balance Sheet Components - Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 31,856	$ 31,856
Accumulated Amortization	31,189	28,521
Net Carrying Amount	667	3,335
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,293	2,293
Accumulated Amortization	2,293	2,293
Net Carrying Amount	0	0
User relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	18,678	18,678
Accumulated Amortization	18,011	15,343
Net Carrying Amount	667	3,335
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,356	10,356
Accumulated Amortization	10,356	10,356
Net Carrying Amount	0	0
Domain names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	529	529
Accumulated Amortization	529	529
Net Carrying Amount	$ 0	$ 0

Balance Sheet Components - Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2021	$ 667
Net Carrying Amount	$ 667	$ 3,335

Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities and Other Liabilities [Abstract]
Accrued compensation and related benefits	$ 14,007	$ 5,344
Accrued freelancer costs	1,235	622
Accrued indirect taxes	3,818	2,401
Accrued vendor expenses	8,662	5,485
Accrued payment processing fees	1,219	832
Operating lease liability, current	3,725	3,214
Other	202	444
Total accrued expenses and other current liabilities	$ 32,868	$ 18,342

Balance Sheet Components - Lessee, Operating Lease, Disclosure (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Operating lease asset	$ 19,729	$ 21,908
Operating lease liability, current	3,725	3,214
Operating lease liability, noncurrent	20,506	21,186
Total	$ 24,231	$ 24,400
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	upwk:AccruedExpensesAndOtherCurrentLiabilities	upwk:AccruedExpensesAndOtherCurrentLiabilities

Balance Sheet Components - Schedule of Operating Lease Liability Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
2021	$ 3,919
2022	5,391
2023	6,519
2024	5,843
2025	2,356
Thereafter	4,937
Total lease payments	28,965
Adjustment for discount to present value	(4,734)
Total	$ 24,231	$ 24,400

Commitments and Contingencies - Narrative (Details) $ in Millions	Dec. 31, 2020 USD ($) letter	Dec. 31, 2019 USD ($) letter
Commitments and Contingencies Disclosure [Abstract]
Letters of credit (in letter) \| letter	3	3
Letters of credit outstanding, amount \| $	$ 1.0	$ 0.8

Debt - Summary of Carrying Value of Debt (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) installment	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Total debt	$ 10,750	$ 18,321
Less: Unamortized debt discount issuance costs	(27)	(38)
Balance	10,723	18,283
Debt, current	(7,581)	(7,584)
Debt, noncurrent	$ 3,142	$ 10,699
Weighted-average interest rate	5.64%	6.93%
First term loan—18 months of interest-only payments ended in March 2019 followed by 36 equal monthly installments of principal plus interest, maturing March 2022; interest at prime plus 0.25% per annum
Debt Instrument [Line Items]
Interest only payments term	18 months
Number of equal monthly installments of principal and interest \| installment	36
Total debt	$ 6,250	$ 11,250
First term loan—18 months of interest-only payments ended in March 2019 followed by 36 equal monthly installments of principal plus interest, maturing March 2022; interest at prime plus 0.25% per annum \| Prime Rate
Debt Instrument [Line Items]
Debt, variable rate	0.25%
Second term loan—17 months of interest-only payments ended in March 2019 followed by 42 equal monthly installments of principal plus interest, maturing September 2022; interest at prime plus 0.25% per annum
Debt Instrument [Line Items]
Interest only payments term	17 months
Number of equal monthly installments of principal and interest \| installment	42
Total debt	$ 4,500	$ 7,071
Second term loan—17 months of interest-only payments ended in March 2019 followed by 42 equal monthly installments of principal plus interest, maturing September 2022; interest at prime plus 0.25% per annum \| Prime Rate
Debt Instrument [Line Items]
Debt, variable rate	0.25%

Debt - Narrative (Details)		1 Months Ended					12 Months Ended
Debt - Narrative (Details)	Feb. 28, 2019	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity						$ 49,000,000.0
Adjusted liquidity ratio	1.30		1.75			0.0175
Debt Covenant, Reduction In Frequency Of Providing Financial Information, Adjusted Quick Ratio To Maintain			2.50
Proceeds from Lines of Credit		$ 25,000,000.0	$ 25,000,000.0
Proceeds from borrowings					$ 15,000,000.0
Repayments of Debt							$ 25,621,000	$ 55,679,000	$ 25,000,000
Revolving Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity						$ 25,000,000.0
First Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount						15,000,000.0
Repayments of Debt							5,000,000.0	3,800,000
Second Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount						$ 9,000,000.0
Repayments of Debt							$ 2,600,000	$ 1,900,000
Loan Agreement
Debt Instrument [Line Items]
Repayment of debt owed				$ 10,000,000.0

Debt - Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2021	$ 7,571
2022	3,179
Total	$ 10,750	$ 18,321

Redeemable Convertible Preferred Stock - Narrative (Details)	1 Months Ended
	Oct. 31, 2018 $ / shares shares
Redeemable Noncontrolling Interest [Line Items]
Redeemable convertible preferred stock, shares outstanding (in shares)	61,279,079
IPO
Redeemable Noncontrolling Interest [Line Items]
Number of shares issued in stock transaction (in shares)	7,840,908
Price per share of stock transaction (in dollars per share) \| $ / shares	$ 15.00

Preferred and Common Stock Warrants - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2018
Class of Warrant or Right [Line Items]
Proceeds from Warrant Exercises	$ 1,200
Class of warrant or right, warrants surrendered	64,646	29	37
Stock issued during period, warrant exercises (in shares)	333,685	49,971	49,963
Reclassification of redeemable convertible preferred stock warrant liability to redeemable convertible preferred stock				$ 6,100
Common stock warrant exercisable conversion		10.00%
Revaluation of warrant expense		$ 750	$ 711	$ 226
Redeemable Convertible Preferred Stock Warrants \| Series A1 Redeemable Convertible Preferred Stock
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)		$ 3.13
Redeemable Convertible Preferred Stock Warrants \| Series A1 Redeemable Convertible Preferred Stock \| Maximum
Class of Warrant or Right [Line Items]
Number of shares issued upon exercisable of warrants		124,506
Redeemable Convertible Preferred Stock Warrants \| Series A2 Redeemable Convertible Preferred Stock
Class of Warrant or Right [Line Items]
Number of shares issued upon exercisable of warrants		273,825
Common Stock Warrant
Class of Warrant or Right [Line Items]
Number of shares issued upon exercisable of warrants		45,286
Exercise price of warrants (in dollars per share)		$ 0.06
Shares issued upon exercise of warrants (in shares)				45,286
Common Stock Warrant \| Tides Foundation
Class of Warrant or Right [Line Items]
Number of shares issued upon exercisable of warrants					500,000
Exercise price of warrants (in dollars per share)					$ 0.01
Class of warrant or right, exercised (in shares)		50,000	50,000

Preferred and Common Stock Warrants - Assumptions Used to Calculate Fair Value of Outstanding Warrants (Details) - Redeemable Convertible Preferred Stock Warrants	Oct. 31, 2018
Dividend yield
Class of Warrant or Right [Line Items]
Outstanding warrants measurement input	0
Expected term (in years)
Class of Warrant or Right [Line Items]
Outstanding warrants measurement input	2 years 9 months
Risk-free interest rates
Class of Warrant or Right [Line Items]
Outstanding warrants measurement input	0.018
Expected volatility
Class of Warrant or Right [Line Items]
Outstanding warrants measurement input	0.346

Preferred and Common Stock - Narrative (Details)	Dec. 31, 2020 vote $ / shares shares	Dec. 31, 2019 $ / shares shares
Equity [Abstract]
Preferred stock (in shares)	10,000,000	10,000,000
Preferred stock (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001
Common Stock, votes per share (in votes) \| vote	1
Common stock, shares authorized (in shares)	490,000,000	490,000,000

Preferred and Common Stock - Reserved for Future Issuance (Details) - shares	Dec. 31, 2020	Dec. 31, 2019	Oct. 03, 2018	Aug. 31, 2018
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	31,578,734	36,180,533
2018 Equity Incentive Plan
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	18,332,765	16,091,801	10,701,505
2018 Employee Stock Purchase Plan
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	2,419,154	1,994,971		1,700,000
Warrant to purchase common stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	400,000	450,000
Options issued and outstanding
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	4,858,590	15,140,579
RSUs issued and outstanding
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	5,568,225	2,503,182

Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended				4 Months Ended	12 Months Ended
	Jan. 31, 2019 shares	Aug. 31, 2018 offering_period shares	Oct. 31, 2017 shares	Aug. 31, 2014 shares	Jun. 30, 2014 shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares	Jan. 01, 2019 shares	Oct. 03, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares) \| shares						31,578,734	36,180,533
Stock-based compensation expense						$ 25,508	$ 18,798	$ 10,361
Dividend yield						0.00%
Intrinsic value of options exercised						$ 124,100	$ 73,000	$ 18,000
Weighted-average grant-date fair value of options granted (in dollars per share) \| $ / shares								$ 3.65
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares) \| shares						4,858,590	15,140,579
Stock-based compensation expense						$ 2,500	$ 8,500	$ 8,600
RSUs issued and outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares) \| shares						5,568,225	2,503,182
Stock-based compensation expense						$ 20,000	$ 7,900	$ 1,100
Fully vested non-option equity instruments granted (in shares) \| shares							35,494
Value of equity granted							$ 500
Share-based tax liability of granted shares							$ 200
Shares surrendered to pay for tax liability \| shares							12,648
Granted (in dollars per share) \| $ / shares						$ 10.96	$ 16.15	$ 15.00
Fair value of awards vested						$ 20,300	$ 2,600
Common stock issuable in connection with employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares under 2018 ESPP (in shares) \| shares	908,835
ESPP Plan shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense						$ 3,200	$ 2,600	$ 600
Elance-oDesk Assumed Award Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount on share at purchase date from original option price						16.14%
Vesting period						4 years
Expiration period						10 years
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					4 years
Expiration period					10 years
Shares available for grant \| shares					12,462,985
Shares issued in period \| shares		100,000	4,500,000	3,001,091
Grant price, threshold of fair value price must meet					100.00%
2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant \| shares									5,680,219
Common stock shares reserved for future issuance (in shares) \| shares						18,332,765	16,091,801			10,701,505
Dividend yield								0.00%
Initial offering period of ESPP		24 months
Common shares under 2018 ESPP (in shares) \| shares						484,652
2018 Equity Incentive Plan \| Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation cost						$ 1,900
Unrecognized stock-based compensation cost, weighted average period of recognition						1 year 2 months 12 days
2018 Equity Incentive Plan \| RSUs issued and outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation cost						$ 62,800
Unrecognized stock-based compensation cost, weighted average period of recognition						2 years 10 months 24 days
Transition Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Monthly fee						$ 40
Stock-based compensation expense						$ 3,500
Dividend yield						0.00%
2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount on share at purchase date from original option price		15.00%
Common stock shares reserved for future issuance (in shares) \| shares		1,700,000				2,419,154	1,994,971
Dividend yield						0.00%	0.00%	0.00%
Unrecognized stock-based compensation cost						$ 2,300
Initial offering period of ESPP		24 months
Number of offering periods in ESPP \| offering_period		4
Length of offering period		6 months
Common stock percentage of purchase price		85.00%

Stock-Based Compensation - Fair Value Assumptions (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Transition Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Transition Agreement \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	3 months 18 days
Risk-free interest rates	1.50%
Expected volatility	38.00%
Transition Agreement \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	1 year 3 months 18 days
Risk-free interest rates	1.60%
Expected volatility	39.00%
2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield			0.00%
2018 Equity Incentive Plan \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)			5 years 2 months 12 days
Risk-free interest rates			2.50%
Expected volatility			38.00%
2018 Equity Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)			6 years 1 month 6 days
Risk-free interest rates			2.90%
Expected volatility			45.00%
2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected volatility			37.00%
2018 Employee Stock Purchase Plan \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months
Risk-free interest rates	0.10%	1.50%	2.40%
Expected volatility	50.00%	38.00%
2018 Employee Stock Purchase Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	2 years	2 years	2 years
Risk-free interest rates	0.20%	2.40%	2.90%
Expected volatility	82.00%	47.00%

Stock-Based Compensation - Summary of Activity under Stock Option Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Shares Underlying Outstanding Options
Beginning Balance (in shares)	15,140,579
Exercised (in shares)	(9,065,976)
Forfeited and canceled (in shares)	(1,216,013)
Ending Balance (in shares)	4,858,590	15,140,579
Vested and exercisable (in shares)	3,876,252
Vested and expected to vest (in shares)	4,858,590
Weighted-Average Exercise Price
Beginning Balance (in dollars per share)	$ 3.61
Exercised (in dollars per share)	3.42
Forfeited and canceled (in dollars per share)	4.08
Ending Balance (in dollars per share)	3.83	$ 3.61
Vested and exercisable (in dollars per share)	3.74
Vested and expected to vest (in dollars per share)	$ 3.83
Weighted-Average Remaining Contractual Term (Years)	5 years 9 months 18 days	6 years 2 months 8 days
Weighted-Average Remaining Contractual Term (Years), Vested and exercisable	5 years 6 months 18 days
Weighted-Average Remaining Contractual Term (Years), Vested and expected to vest	5 years 9 months 18 days
Aggregate Intrinsic Value (in thousands), Vested and exercisable	$ 119,303
Aggregate Intrinsic Value (in thousands), Vested and expected to vest	149,046
Aggregate Intrinsic Value (in thousands)	$ 149,046	$ 106,967

Stock-Based Compensation - Summary of Activity under Restricted Stock Unit Plans (Details) - RSUs issued and outstanding - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of RSUs Outstanding
Unvested balance - beginning balance (in shares)	2,503,182
Granted (in shares)	5,750,034
Vested (in shares)	(1,590,225)
Forfeited/canceled (in shares)	(1,094,766)
Unvested balance - ending balance (in shares)	5,568,225	2,503,182
Weighted-Average Grant Date Fair Value
Unvested balance - beginning balance (in dollars per share)	$ 15.82
Granted (in dollars per share)	10.96	$ 16.15	$ 15.00
Vested (in dollars per share)	13.15
Forfeited/canceled (in dollars per share)	12.70
Unvested balance - ending balance (in dollars per share)	$ 12.20	$ 15.82

Stock-Based Compensation - Components of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	$ 25,508	$ 18,798	$ 10,361
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	779	456	282
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	9,783	6,471	3,258
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	4,440	2,609	1,637
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	$ 10,506	$ 9,262	$ 5,184

Net Loss per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss	$ (22,867)	$ (16,659)	$ (19,907)
Denominator:
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (in shares)	118,698,567	109,814,604	52,327,518
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.19)	$ (0.15)	$ (0.38)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Net Loss per Share - Schedule of Potentially Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from computation of diluted net loss per share attributable to common stockholders	11,367,395	19,745,024	24,961,070
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from computation of diluted net loss per share attributable to common stockholders	4,858,590	15,140,579	23,774,279
Common stock issuable upon exercise of common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from computation of diluted net loss per share attributable to common stockholders	400,000	450,000	898,331
Common stock issuable upon vesting of restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from computation of diluted net loss per share attributable to common stockholders	5,568,225	2,503,182	288,460
Common stock issuable in connection with employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from computation of diluted net loss per share attributable to common stockholders	540,580	1,651,263	0

Income Taxes - Loss Before Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (22,748)	$ (16,658)	$ (19,925)
Foreign	31	27	33
Total loss before income taxes	$ (22,717)	$ (16,631)	$ (19,892)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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+ Details

Income Taxes - Components of Income Tax Benefit (Provision) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ (19)	$ 0	$ 0
State	(127)	(26)	(11)
Foreign	(4)	(2)	(4)
Total current	(150)	(28)	(15)
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Total deferred	0	0	0
Total income tax benefit (provision)	$ (150)	$ (28)	$ (15)

Income Taxes - Effective Tax Rate (Details)	12 Months Ended
Income Taxes - Effective Tax Rate (Details)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax at federal statutory rate	21.00%	21.00%	21.00%
State tax, net of federal benefit	(0.49%)	(0.27%)	1.88%
Stock-based compensation	94.02%	51.45%	(5.84%)
Warrant expense	0.00%	0.00%	(6.98%)
Other items	(0.59%)	(4.34%)	(1.46%)
Research and development credits	9.74%	13.74%	10.54%
Net operating loss expiration	(14.00%)	(18.33%)	0.00%
Change in valuation allowance	(110.34%)	(63.42%)	(19.21%)
Effective tax rate	(0.66%)	(0.17%)	(0.07%)

Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating loss carryforwards	$ 77,230	$ 48,988
Stock-based compensation	230	4,192
Operating lease liability	5,555	10,248
Non-deductible accrued expenses, reserves and other	4,903	2,596
Research and development credits	11,352	8,762
Gross deferred tax assets	99,270	74,786
Valuation allowance	(92,390)	(63,542)	$ (49,439)	$ (45,364)
Total deferred tax assets	6,880	11,244
Deferred tax liabilities:
Acquired intangible assets	(89)	(693)
Operating lease asset	(4,523)	(9,202)
Depreciation and amortization	(2,268)	(1,349)
Deferred Tax Liabilities, Gross	(6,880)	(11,244)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
Effective tax rate	(0.66%)	(0.17%)	(0.07%)
Deferred tax assets, valuation allowance	$ 92,390	$ 63,542	$ 49,439	$ 45,364
Operating loss carryforwards expiration	$ 15,100
Change in valuation allowance	(110.34%)	(63.42%)	(19.21%)
Tax credit carryforward, subject to expiration	$ 200
Unrecognized tax benefits	13,338	$ 12,782	$ 10,973	$ 10,200
Unrecognized tax benefits that impact effective tax rate	0
Forecast [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards expiration					$ 21,600
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	343,100	220,400
Tax credit carryforwards	12,000	10,100
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	72,900	50,300
Change in valuation allowance				80.00%
Tax credit carryforwards	$ 13,100	$ 11,300

Income Taxes - Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance [Line Items]
Balance at Beginning of Year	$ 63,542	$ 49,439	$ 45,364
Additions (deductions)	0	0	0
Balance at End of Year	92,390	63,542	49,439
Cost and Expenses
Valuation Allowance [Line Items]
Additions (deductions)	28,848	14,103	4,075
Other Accounts
Valuation Allowance [Line Items]
Additions (deductions)	$ 0	$ 0	$ 0

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits—beginning balance	$ 12,782	$ 10,973	$ 10,200
Increase related to tax positions taken during prior year	131	0	108
Decrease related to tax positions taken during prior year	0	(164)	(2)
Increase related to tax positions taken during current year	608	1,973	667
Decrease related to tax positions taken during current year	0	0	0
Decrease related to expiration of unrecognized tax benefit	(183)	0	0
Gross unrecognized tax benefits—ending balance	$ 13,338	$ 12,782	$ 10,973

Segment and Geographical Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

Segment and Geographical Information - Revenue by Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 373,628	$ 300,562	$ 253,354
Marketplace
Disaggregation of Revenue [Line Items]
Revenue	338,152	268,284	223,831
Managed services
Disaggregation of Revenue [Line Items]
Revenue	$ 35,476	$ 32,278	$ 29,523

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Segment and Geographical Information - Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 373,628	$ 300,562	$ 253,354
Freelancers
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	226,699	187,442	163,242
Freelancers \| United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	60,861	50,154	40,313
Freelancers \| India
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	33,109	27,369	25,485
Freelancers \| Philippines
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	22,924	19,660	17,057
Freelancers \| Rest of world
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	109,805	90,259	80,387
Clients
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	146,929	113,120	90,112
Clients \| United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	107,359	87,241	65,578
Clients \| Rest of world
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 39,570	$ 25,879	$ 24,534

- Definition

+ References

+ Details

401(k) Plan (Details) - USD ($)	12 Months Ended
401(k) Plan (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Company matching cash contributions	50.00%
Maximum annual contributions per employee	$ 5,000
Expense for matching contributions	$ 2,500,000	$ 2,000,000.0	$ 1,700,000

Subsequent Events (Details)	Jan. 18, 2021 shares
Subsequent Event \| CEO \| 2018 Equity Incentive Plan
Subsequent Event [Line Items]
Number of shares approved	1,500,000