Accrued Restructuring Expenses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 200	$ 1,700		$ 192	$ 1,731
Lease expiration date			2021