Additional Balance Sheet Detail - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses	$ 3,668	$ 2,796
Prepaid sign-on bonuses subject to vesting provisions	147	179
Interest income receivable	176	111
Other	74	284
Total prepaid expenses and other current assets	$ 4,065	$ 3,370