Investments and Fair Value Measurements - Cash, Cash Equivalent and Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents:	$ 62,510	$ 166,068	$ 687,986
Marketable securities, current	419,905	361,795
Marketable securities, non-current	284,951	528,911
Total marketable securities	704,856	890,706
Total cash, cash equivalents and marketable securities	767,366	1,056,774
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Marketable securities, current	274,449	184,946
Marketable securities, non-current	53,555	239,528
Total marketable securities	328,004	424,475
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Marketable securities, current	77,241	11,327
Marketable securities, non-current	173,509	197,298
Total marketable securities	250,750	208,625
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Marketable securities, current	16,489	124,089
Total marketable securities	16,489	124,089
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Marketable securities, current	31,840	21,576
Marketable securities, non-current	55,648	77,142
Total marketable securities	87,488	98,717
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Marketable securities, current	0	2,250
Total marketable securities	2,239	4,562
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Marketable securities, non-current	2,239	2,312
Foreign government and supranational securities
Debt Securities, Available-for-sale [Line Items]
Marketable securities, current	19,886	17,607
Marketable securities, non-current	0	12,631
Total marketable securities	19,886	30,238
Cash
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents:	48,864	134,774
Money market funds
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents:	9,665	31,294
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents:	$ 3,981	$ 0

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

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