Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Clinical trial expenses	$ 7,920	$ 6,573
Employee compensation and related expenses	2,851	4,216
Restructuring expenses	0	660
Manufacturing expenses	228	458
Other	607	945
Total accrued expenses	$ 11,606	$ 12,852