Stockholders' Equity - Basic and Diluted Net Income Per Common Shares (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net (loss) income	$ (976)	$ 1,498	$ (465)	$ 2,352
Denominator:
Basic weighted average outstanding shares of common stock (shares)	19,750,941	20,353,801	19,888,606	20,441,781
Diluted weighted average outstanding shares of common stock (in shares)	19,750,941	20,366,102	19,888,606	20,508,473
Basic net (loss) income per common share (usd per share)	$ (0.05)	$ 0.07	$ (0.02)	$ 0.12
Diluted net (loss) income per common share (usd per share)	$ (0.05)	$ 0.07	$ (0.02)	$ 0.11