Fair Value Measurements - Summary of Changes in Fair Value of Company's Level 3 Fair Value Measurements (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accrued Warrant Liability [Member]
Beginning Balance	$ 4,105,659	$ 7,285,959
Total (gains) or losses, realized and unrealized, included in earnings	(2,864,348)	(7,701,981)
Issuances		4,521,681
Ending Balance	1,241,311	4,105,659
Compensatory Stock Options not Yet Issued [Member]
Beginning Balance		378,750
Total (gains) or losses, realized and unrealized, included in earnings		51,823
Estimates and other changes in fair value	309,450
Settlements		(430,573)
Ending Balance	$ 309,450