Component of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities [Line Items]
Clinical consulting services	$ 2,331	$ 2,802
Preclinical services	3,976	2,027
Employee compensation	1,453	768
Professional services	317	422
Payroll taxes and benefits	289	417
Manufacturing services	253	308
Accrued vacation	221	212
Other consulting services	66	226
Total	$ 8,906	$ 7,182