Net Loss per Share of Common Stock - Summary of Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net loss	$ (36,597)	$ (22,118)	$ (66,319)	$ (46,349)
Weighted-average shares used to compute basic and diluted net loss per share	35,316	29,489	35,001	29,455
Basic and diluted net loss per common share	$ (1.04)	$ (0.75)	$ (1.89)	$ (1.57)