Net Income (Loss) Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income (loss)	$ 1,998	$ (333)	$ 1,825	$ (25,735)
Weighted average common basic shares	41,200	41,096	41,174	41,074
Effect of dilutive securities	33		63
Weighted average common dilutive shares	41,233	41,096	41,237	41,074
Basic and diluted net income (loss) per share	$ 0.05	$ (0.01)	$ 0.04	$ (0.63)