Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued professional fees	$ 1,105	$ 871
Accrued research and development expenses	623	907
Accrued payroll and related expenses	186	394
Accrued other	229	217
Total	$ 2,143	$ 2,389