Income Taxes - Loss Before Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ (155,375)	$ (81,931)	$ (56,414)
Foreign	2,727	1,260	1,986
Loss before provision (benefit) for income taxes	$ (152,648)	$ (80,671)	$ (54,428)