Net Loss Per Share - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net loss	$ (11,542)	$ (4,787)	$ (35,308)	$ (15,160)
Weighted-average common shares outstanding:
Basic and Diluted	27,282,863	25,545,164	27,275,133	23,737,443
Net loss per share, Basic and Diluted	$ (0.42)	$ (0.19)	$ (1.29)	$ (0.64)