Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued research and development expenses	$ 3,808	$ 2,258
Accrued compensation and benefits	2,254	4,551
Accrued professional fees	642	542
Accrued unvested common stock subject to repurchase	25	37
Accrued other	220	256
Total accrued expenses and other liabilities	$ 6,949	$ 7,644