Fair Value Measurement - Summary of Investments Measured and Recognized at Fair Value (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 171,037	$ 200,673
Gross Unrealized Gains	296	52
Gross Unrealized Losses		(9)
Fair Value	171,333	200,716
U.S. Treasury Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	55,700	66,244
Gross Unrealized Gains	72	48
Fair Value	55,772	66,292
Corporate Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	33,344	39,953
Gross Unrealized Gains	150	3
Fair Value	33,494	39,956
Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	18,027	74,507
Gross Unrealized Gains	13
Gross Unrealized Losses		(9)
Fair Value	18,040	74,498
U.S. Government Agency Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	63,966	19,969
Gross Unrealized Gains	61	1
Fair Value	$ 64,027	$ 19,970