Subsequent Events - Additional Information (Detail) (Subsequent Event, USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Feb. 11, 2013
Subsequent Event
Subsequent Event [Line Items]
Number of common shares that are available for sale and issuance	7,500,000
Common stock issuance price	$ 4.00
Common shares that are available for sale and issuance	$ 30.0
Warrants to purchase common stock	2,000,000
Exercise price of warrants	$ 5.00