Stockholders' Equity - Summary of Outstanding Warrants (Detail) - Warrants [Member] - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Class Of Warrant Or Right [Line Items]
Balance outstanding, Beginning, Number of Warrants	873,336
Warrants expired, Number of Warrants	(156,586)
Balance outstanding, Ending, Number of Warrants	716,750	873,336
Warrants exercisable at September 30, 2015, Number of Warrants	716,750
Balance outstanding, Beginning, Weighted Average Exercise Price	$ 17.79
Warrants expired, Weighted Average Exercise Price	26.07
Balance outstanding, Ending, Weighted Average Exercise Price	15.98	$ 17.79
Warrants exercisable at September 30, 2015, Weighted Average Exercise Price	$ 15.98
Balance outstanding, Weighted Average Remaining Contractual Life (in years)	5 months 19 days	1 year 22 days
Warrants exercisable at September 30, 2015, Weighted Average Remaining Contractual Life (in years)	5 months 19 days