Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accounts payable	$ 4,828	$ 9,100
Accrued research projects	5,864	6,637
Accrued professional fees	706	635
Accrued compensation and benefits	2,554	3,293
Total	$ 13,952	$ 19,665