Subsequent Event - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	9 Months Ended		1 Months Ended
	May 31, 2013	Sep. 30, 2013	Dec. 31, 2012	Oct. 31, 2013 Subsequent Event	Oct. 31, 2013 Subsequent Event Over-allotment Option Exercise By Underwriters
Subsequent Event [Line Items]
Common stock, shares issued	8,901,675	110,347,285	98,798,065	10,615,385	1,384,615
Common stock, per share	$ 2.30	$ 0.01	$ 0.01	$ 6.50
Proceed from offering	$ 29,100	$ 29,068		$ 64,700