Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash equivalents:
Cash equivalents	$ 208,841	$ 95,503
Short-term investments:
Short-term investments	32,654	233,663
Money Market Fund
Cash equivalents:
Cash equivalents	208,841	55,505
U.S. Government Treasury Securities
Cash equivalents:
Cash equivalents		39,998
U.S. Government Treasury Securities
Short-term investments:
Short-term investments	32,654	233,663
Level 1
Cash equivalents:
Cash equivalents	208,841	95,503
Short-term investments:
Short-term investments	32,654	233,663
Level 1 | Money Market Fund
Cash equivalents:
Cash equivalents	208,841	55,505
Level 1 | U.S. Government Treasury Securities
Cash equivalents:
Cash equivalents		39,998
Level 1 | U.S. Government Treasury Securities
Short-term investments:
Short-term investments	$ 32,654	$ 233,663