Organization and Basis of Presentation - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended								0 Months Ended	1 Months Ended		0 Months Ended	1 Months Ended	9 Months Ended		3 Months Ended	8 Months Ended
	Feb. 28, 2013	Sep. 30, 2013	Sep. 30, 2012	May 31, 2013	Mar. 15, 2013	Dec. 31, 2012	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Minimum [Member]	Mar. 15, 2013 March 2013 [Member]	Oct. 29, 2013 Subsequent Event [Member]	Oct. 31, 2013 Subsequent Event [Member]	Oct. 29, 2013 Subsequent Event [Member] Series B Warrants [Member]	Oct. 29, 2013 Subsequent Event [Member] Series A Warrants [Member]	Mar. 15, 2013 Hercules Technology Growth Capital Inc. [Member]	Sep. 30, 2013 Hercules Technology Growth Capital Inc. [Member]	Sep. 10, 2013 Hercules Technology Growth Capital Inc. [Member]	Mar. 31, 2013 ATM Program [Member]	Feb. 15, 2013 ATM Program [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of common stock issued through company ATM Program																	4,700,000
Proceeds from sale of common stock, gross																	$ 8,800,000
Proceeds from sale of common stock, net																	8,500,000
Number of common stock shares sold through public offering	6,100,000																	6,600,000
Gross proceeds issuance of common stock	7,900,000																	14,400,000
Net proceeds from issuance of common stock	7,300,000	15,789,873	3,093,839															1,380,000
Price of public offering	$ 1.30
Loan payable									6,000,000					6,000,000
Accrued interest rate														10.45%
Maturity period of loan														42 months
Time period of interest payment														First 12 months
Prepayment of loan																6,400,000
Lender fee		425,000													425,000
Warrants issued to purchase common stock												4,343,247	6,857,142	693,202
Warrants issued to purchase common stock, exercise price													0.85	1.12
Expiry date for warrants outstanding															Apr. 26, 2018
Initial carrying value of loan					5,300,000
Warrant Obligation total					563,000
Stock price							$ 1.18	$ 1.16
Expected volatility rate		77.00%
Maturity period of warrant		5 years
Exercise price of share							$ 1.16	$ 1.15
Interest rate of return		0.84%
Change in unobservable inputs		10.00%
Cost of loan discount		727,000
Loss on extinguishment of debt		(983,330)
Common stock issued		43,139,027		75,000		32,204,720				4,228,181
Proceeds from issuance of common stock and warrants		6,000,000								6,000,000
Warrants exercisable date													May 01, 2014
Warrants expiry date													May 01, 2019
Closing date of offering											Oct. 31, 2013
Net proceeds from issuance of common stock and warrants											5,500,000
Payment made to lender		$ 6,425,000													$ 6,400,000