Accrued Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Schedule of Accrued Liabilities [Line Items]
Legal and accounting fees	$ 55	$ 123
Accrued compensation	439	626
Accrued research and development costs and other	1,445	96
Total	$ 1,939	$ 845