Stockholders' Equity - Summary of Warrants Outstanding to Purchase Common Stock (Detail) (USD $)					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 $ 0.01 - 5.00 [Member]	Dec. 31, 2013 Midcap Warrant [Member] $ 0.01 - 5.00 [Member]
Warrants, by Exercise Price Range [Line Items]
Range of Exercise Prices, minimum					$ 0.00
Range of Exercise Prices, maximum					$ 5.00
Number Outstanding	4,192,927	4,279,919	4,553,251	4,311,539		2,356,792
Weighted Average Remaining Contractual Life (Years)						1 year 5 months 9 days
Weighted Average Exercise Price	$ 3.82	$ 3.70	$ 3.66	$ 3.65		$ 3.92
Aggregate Intrinsic Value	$ 9,145,780	$ 4,572,205				$ 4,640,492