Warrants Issued to Purchase Common Stock (Detail)						12 Months Ended
	Dec. 31, 2013	Apr. 30, 2010	Apr. 16, 2010	Nov. 30, 2009	Apr. 18, 2006	Dec. 31, 2013 2007 Loan Agreement	Dec. 31, 2013 Warrant One 2007 Loan Agreement	Dec. 31, 2013 Warrant Two 2007 Loan Agreement	Dec. 31, 2013 Warrant Three 2007 Loan Agreement	Dec. 31, 2013 Warrant Four 2007 Loan Agreement
Class Of Warrant Or Right [Line Items]
Warrant Issuance Date							Jul. 18, 2007	Oct. 18, 2007	Dec. 27, 2007	Dec. 27, 2007
Shares Issuable						3,550,000	1,250,000	1,300,000	300,000	700,000
Expiration Date							Feb. 26, 2014	Feb. 26, 2014	Feb. 26, 2014	Feb. 26, 2014
Warrants exercise price	1.96	1.50	1.50	1.94	7.32		5.13	1.68	5.65	1.68
Outstanding	10,913,873					1,550,000	1,250,000		300,000