Summary of Warrants Outstanding (Detail)	12 Months Ended
	Dec. 31, 2013
Class of Warrant or Right [Line Items]
Warrants outstanding	10,539,767
Placement warrants for services performed, expiration date May 3, 2013
Class of Warrant or Right [Line Items]
Warrants outstanding	2,264,393
Exercise Price	2.04
Expiration Date	Sep. 15, 2014
Investor warrants, expiration date September 15, 2014
Class of Warrant or Right [Line Items]
Warrants outstanding	40,298
Exercise Price	2.04
Expiration Date	Sep. 15, 2014
Placement warrants for services performed, expiration date September 15, 2014
Class of Warrant or Right [Line Items]
Warrants outstanding	8,235,076
Exercise Price	4.02
Expiration Date	Dec. 09, 2014