Stockholders' Equity - Summary of Warrant Activity (Detail) (Warrants [Member], USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Warrants [Member]
Class of Warrant or Right [Line Items]
Balance outstanding, Beginning, Number of Warrants	978,830
Warrants issued, Number of Warrants
Warrants exercised, Number of Warrants
Warrants expired, Number of Warrants	(105,494)
Warrants cancelled, Number of Warrants
Balance outstanding, Ending, Number of Warrants	873,336	978,830
Warrants exercisable at September 30, 2014, Number of Warrants	873,336
Balance outstanding, Beginning, Weighted Average Exercise Price	$ 19.82
Warrants issued, Weighted Average Exercise Price
Warrants exercised, Weighted Average Exercise Price
Warrants expired, Weighted Average Exercise Price	$ 32.68
Warrants cancelled, Weighted Average Exercise Price
Balance outstanding, Ending, Weighted Average Exercise Price	$ 17.79	$ 19.82
Warrants exercisable at September 30, 2014, Weighted Average Exercise Price	$ 17.79
Balance outstanding, Weighted Average Remaining Contractual Life (in years)	1 year 3 months 22 days	1 year 10 months 24 days
Warrants exercisable at September 30, 2014, Weighted Average Remaining Contractual Life (in years)	1 year 3 months 22 days