Reverse Stock Split - Additional Information (Detail)	1 Months Ended	9 Months Ended
	Aug. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Dec. 31, 2012
Equity [Abstract]
Conversion of convertible preferred stock ratio	1	1
Reverse Stock Split	1-for-3.138458
Reverse Stock Split, ratio	3.138458
Increased number of shares of common stock authorized for issuance	250,000,000		250,000,000	12,936,000
Increased number of shares of preferred stock authorized for issuance	20,000,000		20,000,000