Summary of Significant Accounting Policies - Reconciliation of Net Income (Loss) and Weighted Average Shares used in Computing Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic net (loss) income per share
Net (loss) income applicable to common shares									$ (2,834)	$ (4,060)	$ 4,064
Weighted average common shares outstanding									12,150	11,505	11,131
Basic net (loss) income per share of common stock	$ (0.28)	$ 0.00	$ 0.11	$ (0.06)	$ (0.40)	$ 0.09	$ 0.04	$ (0.08)	$ (0.23)	$ (0.35)	$ 0.37
Diluted net (loss) income per share:
Net (loss) income applicable to common shares									$ (2,834)	$ (4,060)	$ 4,064
Weighted average common shares outstanding									12,150	11,505	11,131
Dilutive effects of stock options and restricted stock awards											1,959
Weighted average common shares, assuming dilutive effect of stock options									12,150	11,505	13,090
Diluted net (loss) income per share of common stock	$ (0.28)	$ 0.00	$ 0.09	$ (0.06)	$ (0.40)	$ 0.08	$ 0.04	$ (0.08)	$ (0.23)	$ (0.35)	$ 0.31