Restricted Cash - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 24, 2013	Jan. 31, 2013	Jan. 29, 2013	Jan. 23, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash				$ 500,000		$ 1,000,000
Percentage needed to effect the waiver on the restricted cash	66.67%
Warrants issued to purchase common stock			243,750	187,500	243,750
Cash and cash equivalents	$ 20,172,485	$ 500,000				$ 592,004	$ 2,237,618	$ 7,109,215
Convertible debt
Restricted Cash and Cash Equivalents Items [Line Items]
Convertible debt instrument, effective interest rate		12.00%			12.00%