Share-based Compensation - Summary of Information under Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Grant date fair value of options granted	$ 78	$ 583	$ 1,053
Fair value of options vested	2,668	2,141	920
Total intrinsic value of options exercised	488	353	485
Cash received from options exercised	$ 616	$ 467	$ 525
Weighted-average estimated fair value per share of options granted (in usd per share)	$ 3.62	$ 4.79	$ 4.48