Stockholders' Equity - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at beginning of period | shares	3,468,991
Number of Shares, Exercised | shares	(151,373)
Number of Shares, Forfeitures | shares	(1,183,795)
Number of Shares, Outstanding at end of period | shares	3,042,484
Weighted Average Exercise Price Per Share, Outstanding at beginning of period | $ / shares	$ 4.14
Weighted average Exercise Price Per Share, Exercised | $ / shares	2.07
Weighted Average Exercise Price Per Share, Forfeitures | $ / shares	5.89
Weighted Average Exercise Price Per Share, Outstanding at end of period | $ / shares	$ 2.92
Aggregate Intrinsic Value, Granted | $	$ 0
Aggregate Intrinsic Value, Outstanding at end of period | $	$ 1,466
Officers and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted | shares	83,658
Weighted Average Exercise Price Per Share, Granted | $ / shares	$ 2.64
Others [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted | shares	825,003
Weighted Average Exercise Price Per Share, Granted | $ / shares	$ 1.91