Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Outstanding Warrants Valuation Assumption (Detail)

v2.4.0.8
Stockholders' Equity - Outstanding Warrants Valuation Assumption (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
August 2008 Offering [Member]
   
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate   0.16%
Expected life (in years)   7 months 28 days
Dividend yield      
Volatility   118.00%
Stock price   $ 4.21
October 2009 Offering [Member]
   
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 0.13% 0.25%
Expected life (in years) 9 months 4 days 1 year 9 months 4 days
Dividend yield      
Volatility 49.00% 98.00%
Stock price $ 4.67 $ 4.21
March 2011 Offering [Member]
   
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 0.78% 0.72%
Expected life (in years) 2 years 2 months 16 days 3 years 2 months 16 days
Dividend yield      
Volatility 88.00% 94.00%
Stock price $ 4.67 $ 4.21