Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Tax at the U.S. statutory rate	$ (6,810,000)	$ (7,621,000)	$ (1,778,000)
Change in value of warrant liability	(974,000)	(2,619,000)	(6,739,000)
Stock option expenses			(140,000)
Valuation allowance	7,723,000	10,204,000	8,639,000
Other	61,000	36,000	18,000
Total