Fair Value Measurement and Marketable Securities - Schedule of Financial Assets Measured and Recognized at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	$ 216,541	$ 66,350
Marketable securities, gross unrealized gains	21	69
Marketable securities, gross unrealized losses	(14)	(4)
Marketable securities, estimated fair value	216,548	66,415
Amortized Cost	283,606	100,358
Estimated Fair Value	283,613	100,423
U.S. Government Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	80,020	24,973
Marketable securities, gross unrealized gains	10	32
Marketable securities, estimated fair value	80,030	25,005
Corporate Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	72,573	39,185
Marketable securities, gross unrealized gains	11	37
Marketable securities, gross unrealized losses	(14)	(4)
Marketable securities, estimated fair value	72,570	39,218
Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	63,948	2,192
Marketable securities, estimated fair value	63,948	2,192
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds, amortized Cost	67,065	34,008
Money market funds, estimated Fair Value	$ 67,065	$ 34,008