Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at beginning of period	3,397,529	3,196,100	4,192,927
Number of Shares, Granted	653,373
Number of Shares, Exercised	(147,425)	(235,480)	(1,332,563)
Number of Shares, Forfeitures	(434,486)	(247,720)	(84,744)
Number of Shares, Outstanding at end of period	3,468,991	3,397,529	3,196,100
Weighted Average Exercise Price Per Share, Outstanding at beginning of period	$ 5.42	$ 4.32	$ 3.82
Weighted average Exercise Price Per Share, Exercised	2.01	3.52	3.48
Weighted Average Exercise Price Per Share, Forfeitures	13.17	12.65	5.26
Weighted Average Exercise Price Per Share, Outstanding at end of period	$ 4.14	$ 5.42	$ 4.32
Aggregate Intrinsic Value, Outstanding at beginning of period	$ 3,124	$ 22,881	$ 9,146
Aggregate Intrinsic Value, Granted	$ 0	$ 0	$ 0
Aggregate Intrinsic Value, Outstanding at end of period	$ 0	$ 3,124	$ 22,881
Officers and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	95,000
Weighted Average Exercise Price Per Share, Granted	$ 2.34
Others [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	558,373	684,629	420,480
Weighted Average Exercise Price Per Share, Granted	$ 3.12	$ 8.14	$ 13.86