Cash Equivalents and Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 291,125	$ 322,831
Debt Securities, Available-for-sale [Line Items]
Unrealized Gains	69	296
Unrealized Losses	(69)	(49)
Aggregate Fair Value	231,224
Cash and cash equivalents and available-for-sale securities, amortized cost	484,303	487,538
Cash, cash equivalents, and available-for-sale securities	484,303	487,785
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	12,487	21,489
Unrealized Gains	0	0
Unrealized Losses	0	0
Aggregate Fair Value	12,487	21,489
U.S. treasury debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	52,755	51,731
Unrealized Gains	4	80
Unrealized Losses	(28)	(2)
Aggregate Fair Value	52,731	51,809
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	160,945	147,715
Unrealized Gains	64	214
Unrealized Losses	(41)	(47)
Aggregate Fair Value	160,968	147,882
Foreign government debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,037	1,025
Unrealized Gains	1	2
Unrealized Losses	0	0
Aggregate Fair Value	5,038	1,027
Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	253,079	265,578
Cash and cash equivalents, aggregate fair value	253,079	265,578
Cash and cash equivalents
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	253,079	280,578
Cash and cash equivalents, aggregate fair value	253,079	280,578
Marketable securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	231,224	206,960
Unrealized Gains	69	296
Unrealized Losses	(69)	(49)
Aggregate Fair Value	$ 231,224	$ 207,207

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).

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