Derivative Financial Instruments - Changes in Fair Values of Derivative Liabilities (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative [Line Items]
Derivative income (expense)	$ 553,693	$ 1,803,137	$ 370,979	$ 702,838
Redemptions of Senior Convertible Notes		195,462		633,351
Total derivative income (expense)	553,693	1,998,599	370,979	1,336,189
Senior Convertible Notes [Member]
Derivative [Line Items]
Derivative income (expense)		682,831	47,243	42,269
Warrant Derivatives [Member]
Derivative [Line Items]
Derivative income (expense)	$ 553,693	$ 1,120,306	$ 323,736	$ 660,569