Fair Value Measurements and Marketable Securities - Financial Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	$ 517,502	$ 689,663
Unrealized Gain	34	85
Unrealized Loss	(869)	(3,134)
Fair Value	516,667	686,614
Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	154,106	129,384
Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	362,561	557,230
Level I
Assets, Fair Value Disclosure [Abstract]
Cash	40,679	27,528
Amortized Cost	361,798	363,969
Unrealized Gain	28	13
Unrealized Loss	(604)	(2,156)
Fair Value	361,222	361,826
Level I \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	113,427	90,398
Level I \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	247,795	271,428
Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	115,025	298,166
Unrealized Gain	6	72
Unrealized Loss	(265)	(978)
Fair Value	114,766	297,260
Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	11,458
Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	114,766	285,802
Money market funds \| Level I
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	88,721	85,302
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	88,721	85,302
Money market funds \| Level I \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	88,721	85,302
Money market funds \| Level I \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	0
Treasury bills \| Level I
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	214,666	172,500
Unrealized Gain	28	13
Unrealized Loss	(29)	(131)
Fair Value	214,665	172,382
Treasury bills \| Level I \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	24,706	5,096
Treasury bills \| Level I \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	189,959	167,286
U.S. government securities \| Level I
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	58,411	106,167
Unrealized Gain	0	0
Unrealized Loss	(575)	(2,025)
Fair Value	57,836	104,142
U.S. government securities \| Level I \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	0
U.S. government securities \| Level I \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	57,836	104,142
Commercial paper \| Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	40,075	120,360
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	40,075	120,360
Commercial paper \| Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	8,038
Commercial paper \| Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	40,075	112,322
Corporate bonds \| Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	10,919	85,639
Unrealized Gain	6	3
Unrealized Loss	(41)	(639)
Fair Value	10,884	85,003
Corporate bonds \| Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	3,420
Corporate bonds \| Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	10,884	81,583
Commercial deposits \| Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	15,197	28,945
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	15,197	28,945
Commercial deposits \| Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	0
Commercial deposits \| Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	15,197	28,945
Asset-backed securities \| Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	29,790	33,261
Unrealized Gain	0	31
Unrealized Loss	(182)	(306)
Fair Value	29,608	32,986
Asset-backed securities \| Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	0
Asset-backed securities \| Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	29,608	32,986
Foreign government and agency securities \| Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	2,099	8,176
Unrealized Gain	0	0
Unrealized Loss	(1)	(10)
Fair Value	2,098	8,166
Foreign government and agency securities \| Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	0
Foreign government and agency securities \| Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	2,098	8,166
U.S. agency securities \| Level II
Assets, Fair Value Disclosure [Abstract]
Amortized Cost	16,945	21,785
Unrealized Gain	0	38
Unrealized Loss	(41)	(23)
Fair Value	16,904	21,800
U.S. agency securities \| Level II \| Cash and Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Fair Value	0	0
U.S. agency securities \| Level II \| Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Fair Value	$ 16,904	$ 21,800

No definition available.

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-12

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section 45
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480555/946-210-45-21

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 20
-SubTopic 210
-Topic 946
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480555/946-210-45-20

+ Details

Name:	us-gaap_Cash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_CashMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=upwk_MarketableSecuritiesCurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_DomesticCorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=upwk_CommercialDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=upwk_ForeignGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: