Common Stock - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Stockholders Equity Note [Abstract]
Common stock, authorized	200,000,000	200,000,000
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, issued	78,729,618	65,881,122
Common stock, outstanding	78,729,618	65,881,122
Shares issued upon the exercise of stock options	574,120
Cash proceeds	$ 456,000
Shares issued upon the exercise of warrants	12,224,846
Warrants to purchase through cashless exercise provisions	627,036
Shares issued through cashless exercise provisions	411,512
Warrants to purchase exercised through cash	11,813,334
Proceeds from warrants exercise	15,952,000
Common stock issued	49,530
Fair Value of common stock issued	$ 124,287