v2.4.0.6
Warrants (Details) (Warrant [Member])
6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Warrant [Member]
   
Weighted-average assumptions utilized in the fair value calculations for warrants granted:    
Expected dividend yield 0.00% 0.00%
Expected stock price volatility, minimum 97.00% 97.00%
Expected stock price volatility, maximum 98.00% 98.00%
Risk-free interest rate, minimum 2.32% 3.95%
Risk-free interest rate, maximum 3.03% 4.24%
Expected life of warrants, minimum 7 years 9 months 22 days 8 years 9 months 20 days
Expected life of warrants, maximum 9 years 10 months 28 days 9 years 10 months 15 days