Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued sales and marketing	$ 10,456	$ 5,963
Accrued compensation and benefits	7,548	9,201
Accrued manufacturing expenses	1,062	1,307
Accrued rent obligations	909	1,372
Other	2,573	2,817
Total accrued expenses	$ 22,548	$ 20,660