Stock Benefit Plans, Stock-Based Compensation and Equity Transactions - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Outstanding, Beginning balance	637
Shares, Granted	668
Shares, Forfeited	(150)
Shares Outstanding, Ending balance	1,155	637
Shares, Options vested and exercisable	435
Shares, Options vested and expected to vest	991
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, Outstanding, Beginning balance	$ 24.96
Weighted average exercise price, Granted	4.43
Weighted average exercise price, Forfeited	29.42
Weighted average exercise price, Outstanding, Ending balance	12.17	$ 24.96
Weighted average exercise price, Options vested and exercisable	21.11
Weighted average exercise price, Options vested and expected to vest	$ 13.37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term, Outstanding, balance	7 years 9 months	6 years 4 months 10 days
Weighted average remaining contractual term, Options vested and exercisable	5 years 2 months 12 days
Weighted average remaining contractual term, Options vested and expected to vest	7 years 4 months 28 days
Aggregate intrinsic value, Outstanding, Beginning balance	$ 0
Aggregate intrinsic value, Granted	0
Aggregate intrinsic value, Forfeited	0
Aggregate intrinsic value, Outstanding, Ending balance	0	$ 0
Aggregate intrinsic value, Options vested and exercisable	0
Aggregate intrinsic value, Options vested and expected to vest	$ 0