Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued employee compensation	$ 3,422	$ 5,040
Accrued external research and development costs	1,351	1,475
Accrued professional services and consulting	1,156	902
Accrued facilities costs	296	846
Other expenditures	580	607
Accrued expenses	$ 6,805	$ 8,870