Income Taxes - Loss Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ (72,139)	$ (50,892)	$ (55,330)
Foreign	3,032	2,692	(2,665)
Loss before provision for income taxes	$ (69,107)	$ (48,200)	$ (57,995)