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Warrant Liabilities (Tables)
 3 Months Ended
Mar. 31, 2013
Warrant Liabilities [Abstract]  
Schedule of weighted-average assumptions
The following reflects the weighted-average assumptions for each of the three-month periods indicated:
 
Three Months Ended March 31,
 
 
2013
 
 
2012
 
 
 
 
 
 
 
Risk-free interest rate
 
 
0.45
%
 
 
0.74
%
Expected dividend yield
 
 
0
%
 
 
0
%
Expected lives
 
 
3.21
 
 
 
4.15
 
  Expected volatility
 
 
69.0
%
 
 
89.2
%
Warrants classified as liabilities
 
$
6,067,450
 
 
$
3,972,230
 
Loss on warrant liabilities
 
$
(2,095,220
)
 
$
(3,888,166
)