Stock Options and Warrants - Summary of Changes in Options Outstanding and Related Exercise Prices for Shares of Company's Common Stock Options Issued (Detail) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2009	Mar. 31, 2017	Dec. 31, 2016
2006 Plan and 2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding, Beginning balance		1,460,076	200,909
Number of Options, Granted		548,800	1,346,800
Number of Options, Canceled or expired		(102,684)	(87,633)
Number of Options, Outstanding, Ending balance		1,906,192	1,460,076
Number of Options, Options vested and expected to vest Ending Balance		1,722,271
Number of Options, Options exercisable Ending Balance		371,946
Weighted Average Exercise Price Per Share, Outstanding, Beginning balance		$ 13.21	$ 83.10
Weighted Average Exercise Price Per Share, Granted		1.09	3.41
Weighted Average Exercise Price Per Share, Canceled or expired		6.28	22.80
Weighted Average Exercise Price Per Share, Outstanding, Ending balance		10.10	$ 13.21
Weighted Average Exercise Price, Options vested or expected to vest Ending Balance		10.89
Weighted Average Exercise Price, Options exercisable Ending Balance		$ 40.87
Weighted Average Remaining Contractual Term, Options Outstanding Ending Balance		8 years 11 months 23 days
Weighted Average Remaining Contractual Term, Options vested or expected to vest Ending Balance		8 years 11 months 9 days
Weighted Average Remaining Contractual Term, Options exercisable Ending Balance		7 years 7 months 17 days
Aggregate Intrinsic Value, Options outstanding, Ending balance		$ 355,608
Aggregate Intrinsic Value, Options vested or expected to vest Ending Balance		$ 312,833
Outside Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding, Beginning balance		50,730	50,730
Number of Options, Granted	68,384
Number of Options, Outstanding, Ending balance		50,730	50,730
Weighted Average Exercise Price Per Share, Outstanding, Beginning balance		$ 92.31	$ 92.31
Weighted Average Exercise Price Per Share, Outstanding, Ending balance		$ 92.31	$ 92.31
Weighted Average Remaining Contractual Term, Options exercisable Ending Balance		2 years 7 months 10 days