Subsequent Event - Additional Information (Detail) (USD $)			0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jan. 13, 2014 Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock issued in public offer, shares	24,433,523	24,327,140	3,047,500
Common stock issued in public offer, Underwrites over-allotment option, Shares			397,500
Common stock issued in public offer, Issue price per share			$ 10.65
Gross proceeds from public offering			$ 32,500,000
Net proceeds from public offering			30,300,000
Underwriting discount and expenses			1,900,000
Estimated other offering costs			$ 425,000