Fair Value of Financial Assets and Liabilities - By Type (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Marketable securities:
Amortized Cost	$ 152,738	$ 32,066
Gross Unrealized Gain	7	2
Gross Unrealized Loss	(15)
Fair Value	152,730	32,068
Corporate debt securities
Marketable securities:
Amortized Cost	28,548
Gross Unrealized Gain	3
Gross Unrealized Loss	(7)
Fair Value	28,544
Commercial paper
Marketable securities:
Amortized Cost	70,518	20,483
Fair Value	70,518	20,483
Asset-backed securities
Marketable securities:
Amortized Cost	30,951	4,036
Gross Unrealized Gain	1	1
Gross Unrealized Loss	(7)
Fair Value	30,945	4,037
U.S. government agency debt securities
Marketable securities:
Amortized Cost	22,721	7,547
Gross Unrealized Gain	3	1
Gross Unrealized Loss	(1)
Fair Value	$ 22,723	$ 7,548

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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