Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financial Assets
Financial assets, fair value	$ 120,227	$ 133,775
Money market funds
Financial Assets
Financial assets, fair value	73,798	6,700
U.S. treasury securities
Financial Assets
Financial assets, fair value	46,429	57,181
U.S. government agency securities
Financial Assets
Financial assets, fair value		66,893
Corporate bonds
Financial Assets
Financial assets, fair value		3,001
Level 1
Financial Assets
Financial assets, fair value	73,798	6,700
Level 1 | Money market funds
Financial Assets
Financial assets, fair value	73,798	6,700
Level 2
Financial Assets
Financial assets, fair value	46,429	127,075
Level 2 | U.S. treasury securities
Financial Assets
Financial assets, fair value	$ 46,429	57,181
Level 2 | U.S. government agency securities
Financial Assets
Financial assets, fair value		66,893
Level 2 | Corporate bonds
Financial Assets
Financial assets, fair value		$ 3,001