Warrants - Additional Information (Detail) (USD $)	9 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Mar. 15, 2013 Hercules Technology Growth Capital Inc. [Member]	Sep. 30, 2013 Issued on 2009 [Member]	May 07, 2009 Issued on 2009 [Member]
Securities Financing Transaction [Line Items]
Contractual term of warrant				5 years
Warrant outstanding				200,000
Common stock shares issued for warrants exercisable					200,000
Common stock shares issued for warrants, exercise price					$ 11.35
Expiry date for warrants outstanding				May 07, 2014
Warrants issued to purchase common stock			693,202
Warrants issued to purchase common stock, exercise price			1.12
Class of warrants or rights issuance date			Apr. 26, 2013
Warrants expiration period			5 years
Warrant exercised	0	0