Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Payroll and employee related expenses	$ 2,244	$ 1,892
Third-party research and development expenses	763	381
Professional and consulting fees	831	555
Other	130	149
Total accrued expenses and other current liabilities	$ 3,968	$ 2,977