Operating Matters and Liquidity - Additional Information (Detail) - Class Of Stock [Domain] - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 23, 2014	May. 17, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Net Income Loss			$ (2,166,786)	$ (1,576,647)	$ (4,009,981)	$ (3,241,166)	$ 6,300,000	$ 7,100,000
Accumulated deficit			$ (125,100,293)		$ (125,100,293)		$ (121,090,312)
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.2745
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		32,786,885	89,731		89,731
Venture Loan [Member]
Line of Credit Facility [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.1003
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,492,523
Debt Instrument, Description of Variable Rate Basis	The loan bears interest at a floating rate equal to the One Month LIBOR Rate (with a floor of 0.50%) plus 8.50%. In the event that the One Month LIBOR Rate, as reported in the Wall Street Journal, exceeds 0.50%, the interest rate will be adjusted by an amount equal to the difference between such rates at the end of that particular month.
Debt Instrument, Payment Terms	The loan is to be repaid in forty-five (45) monthly payments consisting of fifteen (15) monthly payments of only interest followed by thirty (30) equal monthly payments of principal and interest. In addition, at the end of the repayment term (or at early termination of the loan) a final payment equal to 4.5% of the loan will be due and payable.
Proceeds from Issuance of Long-term Debt	$ 5,000,000
Debt Instrument, Interest Rate, Stated Percentage	9.00%		9.00%		9.00%
Warrants Expire Term	10 years
December 2014 Private Placement [Member]
Line of Credit Facility [Line Items]
Sale of Stock, Number of Shares Issued in Transaction	50,099,700
Sale of Stock, Price Per Share	$ 0.1003
Sale of Stock, Consideration Received on Transaction	$ 5,025,000
2013 Warrants [Member]
Line of Credit Facility [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.2745
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		32,786,885
Warrants Expire Term		7 years
2014 warrants [Member]
Line of Credit Facility [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.1003
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	50,099,700
Common Stock [Member]
Line of Credit Facility [Line Items]
Net Income Loss					$ 0	$ 0
Sale of Stock, Consideration Received on Transaction		$ 12,000,000
Common Stock [Member] | May 2013 Private Placement [Member]
Line of Credit Facility [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		43,715,847
Sale of Stock, Price Per Share		$ 0.2745
Sale of Stock, Consideration Received on Transaction		$ 12,000,000