Warrant Derivative Liabilities - Schedule of Significant Assumptions or Ranges (Detail) (Warrants derivative liabilities [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Significant assumptions (or ranges):
Term (years)	1 year 9 months 29 days	2 years 9 months 29 days
Level 1 input [Member]
Significant assumptions (or ranges):
Stock price	$ 4.52	$ 9.07
Risk-free rate	0.34%	0.33%
Level 2 input [Member]
Significant assumptions (or ranges):
Volatility	94.00%	70.00%
Dividend yield	0.00%	0.00%
Level 3 input [Member]
Significant assumptions (or ranges):
Scenario probability (fundamental change event/debt raise/equity raise)	60%/40%/0 %	0%/80%/20 %