Derivative Financial Instruments - Changes in Fair Values of Derivative Liabilities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Derivative income (expense)	$ 2,573,165	$ 2,702,761
Redemptions of series G convertible preferred Stock		393,166
Redemptions of senior convertible notes	889,340	536,003
Exercise of warrants	922,875
Total derivative income (expense)	4,385,380	3,631,930
Senior Convertible Notes [Member]
Derivative [Line Items]
Derivative income (expense)	593,001	1,747,133
Series G Convertible Preferred Stock [Member]
Derivative [Line Items]
Derivative income (expense)		(115,955)
Warrant Derivatives [Member]
Derivative [Line Items]
Derivative income (expense)	$ 1,980,164	$ 1,071,583