Cash Equivalents and Marketable Securities - Schedule of Fair Value and Amortized Cost of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Amortized Cost	$ 293,828	$ 140,406	$ 96,674
Amortized Cost	876,356	669,831
Gross Unrealized Gains	4	268
Gross Unrealized Losses	(1,627)	(12)
Fair Value	874,733	670,087
Classified as:
Cash equivalents	270,236	117,879
Marketable securities	320,966	472,213
Marketable securities, non-current	283,531	79,995
Total cash equivalents and marketable securities	874,733	670,087
U.S. Treasury securities
Marketable Securities [Line Items]
Amortized Cost	290,909	202,674
Gross Unrealized Gains	2	27
Gross Unrealized Losses	(1,205)	0
Fair Value	289,706	202,701
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	93,864	205,558
Gross Unrealized Gains	2	207
Gross Unrealized Losses	(240)	(1)
Fair Value	93,626	205,764
Corporate debt securities
Marketable Securities [Line Items]
Amortized Cost	285,338	211,086
Gross Unrealized Gains	0	34
Gross Unrealized Losses	(182)	(11)
Fair Value	285,156	211,109
Money market funds
Marketable Securities [Line Items]
Amortized Cost	206,245	50,513
Fair Value	$ 206,245	$ 50,513

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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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