| Warrants outstanding | 
        
 The Company has the following shares of common
stock reserved for the warrants outstanding as of June 30, 2014: 
  
    |   | 
      | 
    June 30,
    2014 | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Weighted | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Average | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Exercise | 
      | 
 
    |   | 
      | 
    Shares | 
      | 
      | 
    Price | 
      | 
 
    | Warrants outstanding  beginning of year | 
      | 
      | 
    19,550,817 | 
      | 
      | 
    $ | 
    0.17 | 
      | 
 
    | Warrants exercised | 
      | 
      | 
    (9,367,287 | 
    ) | 
      | 
      | 
    0.19 | 
      | 
 
    | Warrants granted | 
      | 
      | 
    5,701,754 | 
      | 
      | 
      | 
    0.30 | 
      | 
 
    | Warrants expired | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | Warrants outstanding  end of period | 
      | 
      | 
    15,885,284 | 
      | 
      | 
    $ | 
    0.21 | 
      | 
 
 
 | 
        
 The Company has the following shares of common
stock reserved for the warrants outstanding as of December 31, 2013: 
  
    |   | 
      | 
    December 31, 2013 | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Weighted | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Average | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    Exercise | 
      | 
 
    |   | 
      | 
    Shares | 
      | 
      | 
    Price | 
      | 
 
    | Warrants outstanding  beginning of year | 
      | 
      | 
    6,711,733 | 
      | 
      | 
    $ | 
    0.35 | 
      | 
 
    | Warrants exercised | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
 
    | Warrants granted | 
      | 
      | 
    12,839,084 | 
      | 
      | 
      | 
    0.08 | 
      | 
 
    | Warrants expired | 
      | 
      | 
    - | 
      | 
      | 
      | 
    - | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | Warrants outstanding  end of period | 
      | 
      | 
    19,550,817 | 
      | 
      | 
    $ | 
    0.17 | 
      | 
 
 
 | 
      
      
        | Weighted exercise price and weighted fair value of the warrants granted | 
        
    |   | 
      | 
    June 30, 2014 | 
      | 
 
    |   | 
      | 
    Weighted | 
      | 
      | 
      | 
      | 
 
    |   | 
      | 
    Average | 
      | 
      | 
    Weighted | 
      | 
 
    |   | 
      | 
    Exercise | 
      | 
      | 
    Average | 
      | 
 
    |   | 
      | 
    Price | 
      | 
      | 
    Fair Value | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | Weighted average of warrants granted during the three months whose exercise price exceeded fair market value at the date of grant | 
      | 
    $ | 
    0.30 | 
      | 
      | 
    $ | 
    0.45 | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | Weighted average of warrants granted during the nine months whose exercise price was equal or lower than fair market value at the date of grant | 
      | 
    $ | 
    - | 
      | 
      | 
    $ | 
    - | 
      | 
 
 
 | 
        
 The weighted exercise price and weighted fair
value of the warrants granted by the Company as of December 31, 2013, are as follows: 
  
    |   | 
      | 
    December 31, 2013 | 
      | 
 
      
  
  
  | 
      
  
  
  | 
    
Weighted 
Average 
Exercise 
Price
 | 
      
  
  
  | 
      
  
  
  | 
      
Weighted 
Average 
Fair Value
 | 
      
  
  
  | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | Weighted average of warrants granted during the nine months whose exercise price exceeded fair market value at the date of grant | 
      | 
    $ | 
    0.32 | 
      | 
      | 
    $ | 
    0.46 | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | Weighted average of warrants granted during the nine months whose exercise price was equal or lower than fair market value at the date of grant | 
      | 
    $ | 
    - | 
      | 
      | 
    $ | 
    - | 
      | 
 
 
 | 
      
      
        | Summarizes information about fixed-price warrants outstanding | 
        
    |   | 
      | 
      | 
    Number | 
      | 
      | 
    Average | 
      | 
      | 
      | 
      | 
 
    | Range of | 
      | 
      | 
    Outstanding at | 
      | 
      | 
    Remaining | 
      | 
      | 
    Weighted | 
      | 
 
    | 
         Exercise  
        Prices 
 | 
      | 
      | 
    
         June 30,  
        2014 
 | 
      | 
      | 
    
         Contractual  
        Life 
 | 
      | 
      | 
    
         Average 
        Exercise Price 
 | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
    | $0.33 | 
      | 
      | 
    5,540,400 | 
      | 
      | 
    13 Months | 
      | 
      | 
    $0.33 | 
      | 
 
    | $0.46 | 
      | 
      | 
    600,000 | 
      | 
      | 
    13 Months | 
      | 
      | 
    $0.46 | 
      | 
 
    | $ 0.46 | 
      | 
      | 
    150,000 | 
      | 
      | 
    7 Months | 
      | 
      | 
    $0.46  | 
      | 
 
    | $0.85 | 
      | 
      | 
    40,000 | 
      | 
      | 
    10 Months | 
      | 
      | 
    $0.85 | 
      | 
 
    | $0.40 | 
      | 
      | 
    333,333 | 
      | 
      | 
    14 Months | 
      | 
      | 
    $0.40 | 
      | 
 
    | $0.33 | 
      | 
      | 
    439,637 | 
      | 
      | 
    17 Months | 
      | 
      | 
    $0.33 | 
      | 
 
    | $ 0.16 | 
      | 
      | 
    750,000 | 
      | 
      | 
    21 Months | 
      | 
      | 
    $0.16 | 
      | 
 
    | $0.06 | 
      | 
      | 
    7,067,002 | 
      | 
      | 
    51 Months | 
      | 
      | 
    $0.06 | 
      | 
 
    | $0.30 | 
      | 
      | 
    964,912 | 
      | 
      | 
    47 Months | 
      | 
      | 
    $0.30 | 
      | 
 
    |   | 
      | 
      | 
      | 
    15,885,284 | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
      | 
 
 
 | 
        
 The following table summarizes information
about fixed-price warrants outstanding: 
  
    |   | 
      | 
      | 
    Number | 
      | 
    Average | 
      | 
      | 
      | 
 
    | Range of | 
      | 
      | 
    Outstanding at | 
      | 
    Remaining | 
      | 
    Weighted | 
      | 
 
    | Exercise | 
      | 
      | 
    December 31, | 
      | 
    Contractual | 
      | 
    Average | 
      | 
 
    | Prices | 
      | 
      | 
    2013 | 
      | 
    Life | 
      | 
    Exercise Price | 
      | 
 
    | $ | 
    0.33 | 
      | 
      | 
      | 
    5,588,400 | 
      | 
    9 Months | 
      | 
    $ | 
    0.33 | 
      | 
 
    | $ | 
    0.46 | 
      | 
      | 
      | 
    600,000 | 
      | 
    20 Months | 
      | 
    $ | 
    0.46 | 
      | 
 
    | $ | 
    0.46 | 
      | 
      | 
      | 
    150,000 | 
      | 
    25 Months | 
      | 
    $ | 
    0.46 | 
      | 
 
    | $ | 
    0.85 | 
      | 
      | 
      | 
    40,000 | 
      | 
    16 Months | 
      | 
    $ | 
    0.85 | 
      | 
 
    | $ | 
    0.40 | 
      | 
      | 
      | 
    333,333 | 
      | 
    20 Months | 
      | 
    $ | 
    0.40 | 
      | 
 
    | $ | 
    0.33 | 
      | 
      | 
      | 
    515,637 | 
      | 
    48 Months | 
      | 
    $ | 
    0.33 | 
      | 
 
    | $ | 
    0.13 | 
      | 
      | 
      | 
    352,978 | 
      | 
    51 Months | 
      | 
    $ | 
    0.13 | 
      | 
 
    | $ | 
    0.16 | 
      | 
      | 
      | 
    875,000 | 
      | 
    51 Months | 
      | 
    $ | 
    0.16 | 
      | 
 
    | $ | 
    0.12 | 
      | 
      | 
      | 
    116,674 | 
      | 
    52 Months | 
      | 
    $ | 
    0.12 | 
      | 
 
    | $ | 
    0.11 | 
      | 
      | 
      | 
    102,733 | 
      | 
    52 Months | 
      | 
    $ | 
    0.11 | 
      | 
 
    | $ | 
    0.05 | 
      | 
      | 
      | 
    267,391 | 
      | 
    55 Months | 
      | 
    $ | 
    0.05 | 
      | 
 
    | $ | 
    0.06 | 
      | 
      | 
      | 
    10,608,671 | 
      | 
    57 Months | 
      | 
    $ | 
    0.06 | 
      | 
 
    |   | 
      | 
      | 
      | 
      | 
    19,550,817 | 
      | 
      | 
      | 
      | 
      | 
      | 
 
 
  
 |