| Series C exchange fair value assumptions for warrrants received | 
        
 In connection with the Series C exchange, we calculated the
fair value of the 686,124 warrants received, as described above, using a binomial model with the below assumptions. 
  
    | Assumptions | 
      | 
    Series C Exchange Warrants | 
 
    | Contractual life (in months) | 
      | 
    64 | 
 
    | Expected volatility | 
      | 
    106.7% | 
 
    | Risk-free interest rate | 
      | 
    0.75% | 
 
    | Exercise price | 
      | 
    $0.74 | 
 
    | Fair value per warrant | 
      | 
    $0.46 | 
 
 
  
 | 
      
      
        | Fair value of the warrants | 
        
 In connection with the warrant modification, we calculated
the fair value of the warrants, as described above, using a Black-Scholes model with the below assumptions: 
  
    | Assumptions | 
    Series A | 
    Series A | 
    Series B | 
    Series C | 
    Aug/Sep 2011 | 
    Feb 2012 | 
 
    |   | 
      | 
    (Affiliates) | 
      | 
      | 
    Notes | 
    PIPE | 
 
    | Contractual life, in years | 
    4.1 | 
    3.1 | 
    3.1 | 
    5.1 | 
    2.1 | 
    4.6 | 
 
    | Expected volatility | 
    132.0% | 
    114.1% | 
    114.1% | 
    121.9% | 
    126.6% | 
    126.6% | 
 
    | Risk-free interest rate | 
    0.4% | 
    0.4% | 
    0.4% | 
    0.4% | 
    0.4% | 
    0.4% | 
 
    | Exercise price | 
    $0.60 | 
    $0.60 | 
    $0.60 | 
    $0.60 | 
    $0.60 | 
    $0.60 | 
 
    | Fair value per warrant | 
    $0.03 | 
    $0.03 | 
    $0.03 | 
    $0.03 | 
    $0.03 | 
    $0.03 | 
 
 
  
 | 
      
      
        | Warrants and Options Outstanding | 
        
 The following tables summarize information concerning options
and warrants outstanding and exercisable: 
  
    |   | 
      | 
    Stock Options | 
      | 
      | 
    Warrants | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Weighted | 
      | 
      | 
      | 
      | 
      | 
    Weighted | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Average price | 
      | 
      | 
      | 
      | 
      | 
    Average price | 
      | 
      | 
    Total | 
      | 
      | 
      | 
      | 
 
    |   | 
      | 
    Shares | 
      | 
      | 
    per share | 
      | 
      | 
    Shares | 
      | 
      | 
    per share | 
      | 
      | 
    Shares | 
      | 
      | 
    Exercisable | 
      | 
 
    | Balance outstanding, January 1, 2012 | 
      | 
      | 
    1,508,500 | 
      | 
      | 
    $ | 
    2.33 | 
      | 
      | 
      | 
    4,775,501 | 
      | 
      | 
    $ | 
    1.35 | 
      | 
      | 
      | 
    6,284,001 | 
      | 
      | 
      | 
    6,112,335 | 
      | 
 
    |       Granted | 
      | 
      | 
    1,896,250 | 
      | 
      | 
      | 
    .81 | 
      | 
      | 
      | 
    2,909,068 | 
      | 
      | 
      | 
    .62 | 
      | 
      | 
      | 
    4,805,318 | 
      | 
      | 
      | 
      | 
      | 
 
    |       Exercised | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
      | 
      | 
 
    |       Expired | 
      | 
      | 
    (130,000) | 
     | 
      | 
      | 
    2.28 | 
      | 
      | 
      | 
    (116,490) | 
     | 
      | 
      | 
    2.80 | 
      | 
      | 
      | 
    (246,490) | 
     | 
      | 
      | 
      | 
      | 
 
    |       Forfeited | 
      | 
      | 
    (1,669,000) | 
     | 
      | 
      | 
    - | 
      | 
      | 
      | 
    (880,980) | 
     | 
      | 
      | 
    2.13 | 
      | 
      | 
      | 
    (2,549,980) | 
     | 
      | 
      | 
      | 
      | 
 
    | Balance outstanding, December 31, 2012 | 
      | 
      | 
    1,605,750 | 
      | 
      | 
    $ | 
    0.80 | 
      | 
      | 
      | 
    6,687,099 | 
      | 
      | 
    $ | 
    0.81 | 
      | 
      | 
      | 
    8,292,849 | 
      | 
      | 
      | 
    7,989,331 | 
      | 
 
    |       Granted | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    4,650,000 | 
      | 
      | 
      | 
    0.40 | 
      | 
      | 
      | 
    4,650,000 | 
      | 
      | 
      | 
      | 
      | 
 
    |       Exercised | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
      | 
      | 
 
    |       Expired | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
      | 
      | 
 
    |       Forfeited | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
      | 
      | 
      | 
      | 
 
    | Balance outstanding, March 31, 2013 | 
      | 
      | 
    1,605,750 | 
      | 
      | 
    $ | 
    0.80 | 
      | 
      | 
      | 
    11,337,099 | 
      | 
      | 
    $ | 
    0.70 | 
      | 
      | 
      | 
    12,942,849 | 
      | 
      | 
      | 
    12,711,330 | 
      | 
 
 
  
    |   | 
      | 
      | 
    Options Outstanding | 
      | 
      | 
    Options Exercisable | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
    Weighted Average | 
      | 
      | 
      | 
      | 
      | 
    Weighted Average | 
      | 
 
    | Range of Exercise Prices | 
      | 
      | 
    Number of Options | 
      | 
      | 
    
         Remaining Contractual 
        Life (Years) 
 | 
      | 
      | 
    Exercise Price | 
      | 
      | 
    Number of Options | 
      | 
      | 
    
         Remaining Contractual 
        Life (Years) 
 | 
      | 
      | 
    Exercise Price | 
      | 
 
    |   | 
    $0.50 - $0.59 | 
      | 
      | 
      | 
    213,750 | 
      | 
      | 
      | 
    9.3 | 
      | 
      | 
    $ | 
    0.50 | 
      | 
      | 
      | 
    168,751 | 
      | 
      | 
      | 
    9.3 | 
      | 
      | 
    $ | 
    0.50 | 
      | 
 
    |   | 
    0.60 - 0.99 | 
      | 
      | 
      | 
    536,000 | 
      | 
      | 
      | 
    6.8 | 
      | 
      | 
      | 
    0.60 | 
      | 
      | 
      | 
    440,313 | 
      | 
      | 
      | 
    6.3 | 
      | 
      | 
      | 
    0.60 | 
      | 
 
    |   | 
    1.00 - 1.50 | 
      | 
      | 
      | 
    856,000 | 
      | 
      | 
      | 
    4.0 | 
      | 
      | 
      | 
    1.00 | 
      | 
      | 
      | 
    765,167 | 
      | 
      | 
      | 
    3.5 | 
      | 
      | 
      | 
    1.00 | 
      | 
 
    |   | 
    $0.50 - $1.50 | 
      | 
      | 
      | 
    1,605,750 | 
      | 
      | 
      | 
    5.65 | 
      | 
      | 
    $ | 
    0.80 | 
      | 
      | 
      | 
    1,374,231 | 
      | 
      | 
      | 
    5.1 | 
      | 
      | 
    $ | 
    0.81 | 
      | 
 
 
  
 |