Subsequent Events - Additional Information (Detail) (Subsequent Event [Member], USD $)	1 Months Ended
	Aug. 09, 2013	Aug. 01, 2013
Subsequent Event [Line Items]
Proceeds from issuance of common stock and warrants	$ 12,000,000	$ 10,900,000
Net proceeds from issuance of common stock and warrants	$ 10.9
Common stock and warrants selling price per unit	1.799
Additional Common stock, shares issued	954,001
Common stock, exercise price	$ 0.01
Warrants exercise price	$ 2.57
Common stock and warrants description	The units consisted of either (at the option of the investors): (i) one share of common stock, one five year warrant and one two year warrant, sold at a price to the public of $1.799, or (ii) (for those investors whose acquisition of our common stock through purchase of new units would cause them to own more than 9.9% of our outstanding common stock), a unit which consisted of one pre-funded warrant (in lieu of the share of common stock), one five year warrant and one two year warrant
Percent of ownership on outstanding common stock and warrants	9.90%
Exercise price of pre-funded warrants	0.01
Common stock or pre-funded warrants to be issued	5,721,675
Five Year Warrants [Member]
Subsequent Event [Line Items]
Warrants to be issued	6,675,676
Two Year Warrants [Member]
Subsequent Event [Line Items]
Warrants to be issued	3,337,838