Fair Value Measurements - Summary of Financial Assets and Liabilities are Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Total assets	$ 24,474	$ 43,631
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Total assets	24,474	43,631
Significant Other Observable Inputs (Level 2)
Assets
Total assets	0	0
Significant Unobservable Inputs (Level 3)
Assets
Total assets	0	0
Money Market
Assets
Cash equivalents - money market	24,474	43,631
Money Market | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash equivalents - money market	24,474	43,631
Money Market | Significant Other Observable Inputs (Level 2)
Assets
Cash equivalents - money market	0	0
Money Market | Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents - money market	$ 0	$ 0