Stock-Based Compensation - Schedule of Stock Option Plans (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares Outstanding, Beginning of the period	306,616	242,654
Number of Shares Granted	1,205,162	499,447
Number of Shares Exercised	0	(1,806)
Number of Shares Forfeited or expired	(202,943)	(433,679)
Number of Shares Outstanding, Ending of the period	1,308,835	306,616	242,654
Number of Shares Vested and exercisable	101,376
Weighted Average Exercise Price per Share Outstanding, Beginning of the period	$ 16.20	$ 40.10
Weighted Average Exercise Price per Share Granted	$ 1.70	$ 14.60
Weighted Average Exercise Price per Share of options Exercised	$ 0	$ 10.00
Weighted Average Exercise Price per Share Forfeited or expired	$ 16.74	$ 27.70
Weighted Average Exercise Price per Share Outstanding, Ending of the period	$ 2.76	$ 16.20	$ 40.10
Weighted Average Exercise Price per Share Vested and exercisable	$ 13.45	$ 25.60
Weighted Average Remaining Contractual Term in Years Granted	9 years 4 months 24 days	9 years 6 months
Weighted Average Remaining Contractual Term in Years Vested and exercisable	8 years 4 months 24 days
Weighted Average Remaining Contractual Term in Years Outstanding	9 years 9 months 18 days	9 years	7 years
Aggregate Intrinsic Value Outstanding (in dollars)		$ 29
Aggregate Intrinsic Value for Granted (in dollars)		0
Aggregate Intrinsic Value for Exercised (in dollars)		17
Aggregate Intrinsic Value for Forfeited or expired (in dollars)		27
Aggregate Intrinsic Value Outstanding Vested and exercisable (in dollars)	$ 0