Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Line Items]
Cash	$ 29,269	$ 23,887
Cash equivalents:	76,869	143,029
Total cash and cash equivalents	106,138	166,916
Marketable securities, amortized cost	236,880	338,004
Marketable securities, gross unrealized gains	8	190
Marketable securities, gross unrealized losses	(2)	(1)
Marketable securities, estimated fair value	236,886	338,193
Total cash, cash equivalents and marketable securities, amortized cost	343,018	504,920
Total cash, cash equivalents and marketable securities	343,024	505,109
Money market funds
Cash and Cash Equivalents [Line Items]
Cash equivalents:	39,422	80,986
Commercial paper
Cash and Cash Equivalents [Line Items]
Cash equivalents:	35,444	61,043
Marketable securities, amortized cost	158,837	210,986
Marketable securities, gross unrealized gains	0	0
Marketable securities, gross unrealized losses	0	0
Marketable securities, estimated fair value	158,837	210,986
Corporate debt securities
Cash and Cash Equivalents [Line Items]
Cash equivalents:	2,003
Marketable securities, amortized cost	14,459	33,288
Marketable securities, gross unrealized gains	2	172
Marketable securities, gross unrealized losses	(2)	0
Marketable securities, estimated fair value	14,459	33,460
U.S. Treasuries
Cash and Cash Equivalents [Line Items]
Marketable securities, amortized cost	15,510	43,050
Marketable securities, gross unrealized gains	1	1
Marketable securities, gross unrealized losses	0	(1)
Marketable securities, estimated fair value	15,511	43,050
Certificate of deposits
Cash and Cash Equivalents [Line Items]
Cash equivalents:		1,000
Marketable securities, amortized cost	41,874	44,480
Marketable securities, gross unrealized gains	0	0
Marketable securities, gross unrealized losses	0	0
Marketable securities, estimated fair value	41,874	44,480
U.S. Government-sponsored enterprises debt securities
Cash and Cash Equivalents [Line Items]
Marketable securities, amortized cost	6,200	6,200
Marketable securities, gross unrealized gains	5	17
Marketable securities, gross unrealized losses	0	0
Marketable securities, estimated fair value	$ 6,205	$ 6,217

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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Amortized cost 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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