Stockholders' Equity - Summary of Warrants Outstanding to Purchase Common Stock (Detail) (USD $)			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 $ 0.01 - 5.00 [Member]	Sep. 30, 2013 $ 0.01 - 5.00 [Member] Midcap Warrant [Member]
Warrants, by Exercise Price Range [Line Items]
Range of Exercise Prices, minimum			$ 0.01
Range of Exercise Prices, maximum			$ 5.00
Number Outstanding	4,135,771	4,279,919		2,366,792
Weighted Average Remaining Contractual Life (Years)				11 months 19 days
Weighted Average Exercise Price	$ 3.79	$ 3.70		$ 3.93
Aggregate Intrinsic Value	$ 7,590,138			$ 3,560,668