| 9. STOCK OPTIONS AND WARRANTS (Tables)
 | 12 Months Ended | 
| Apr. 30, 2015 | 
|---|
| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |  | 
| Assumptions | 
    |  |  | April 30, |  |  
    |  |  | 2015 |  |  | 2014 |  |  | 2013 |  |  
    | Risk-free interest rate |  |  | 2 | % |  |  |  |  |  |  |  |  |  
    | Expected volatility |  |  | 145 | % |  |  |  |  |  |  |  |  |  
    | Expected lives (years) |  |  | 5 |  |  |  |  |  |  |  |  |  |  
    | Expected dividend yield |  |  | 0.00 | % |  |  | 0.00 | % |  |  | 0.00 | % |  | 
| Unvested employee stock option activity | 
    |  |  |  | Options
                                         Outstanding |  |  |  | Weighted
                                         Average Grant Date Fair Value per Share |  |  
    | Nonvested, April 30, 2012 |  |  |  |  |  | $ |  |  |  
    | Granted |  |  |  |  |  |  |  |  |  
    | Vested |  |  |  |  |  |  |  |  |  
    | Forfeited |  |  |  |  |  |  |  |  |  
    | Nonvested, April 30, 2013 |  |  |  |  |  |  |  |  |  
    | Granted |  |  |  |  |  |  |  |  |  
    | Vested |  |  |  |  |  |  |  |  |  
    | Forfeited |  |  |  |  |  |  |  |  |  
    | Nonvested, April 30, 2014 |  |  |  |  |  |  |  |  |  
    | Granted |  |  | 47,200,000 |  |  | $ | 0.14 |  |  
    | Vested |  |  | 40,600,000 |  |  |  | 0.15 |  |  
    | Forfeited |  |  |  |  |  |  |  |  |  
    | Nonvested, April 30, 2015 |  |  | 6,600,000 |  |  | $ | 0.10 |  |  | 
| Employee stock option activity | 
    |  |  |  | Options
                                         Outstanding |  |  |  | Weighted
                                         Average Grant Date Fair Value per Share |  |  
    | Nonvested, April 30, 2012 |  |  |  |  |  | $ |  |  |  
    | Granted |  |  |  |  |  |  |  |  |  
    | Vested |  |  |  |  |  |  |  |  |  
    | Forfeited |  |  |  |  |  |  |  |  |  
    | Nonvested, April 30, 2013 |  |  |  |  |  |  |  |  |  
    | Granted |  |  |  |  |  |  |  |  |  
    | Vested |  |  |  |  |  |  |  |  |  
    | Forfeited |  |  |  |  |  |  |  |  |  
    | Nonvested, April 30, 2014 |  |  |  |  |  |  |  |  |  
    | Granted |  |  | 5,250,000 |  |  | $ | 0.19 |  |  
    | Vested |  |  | 5,250,000 |  |  |  | 0.19 |  |  
    | Forfeited |  |  |  |  |  |  |  |  |  
    | Nonvested, April 30, 2015 |  |  |  |  |  | $ |  |  |  | 
| Range of outstanding stock options | 
    |  |  | Exercise Prices |  |  
    | Range of Exercise Price |  | $ | 0.19 |  |  | $ | 0.11 |  |  | $ | 0.18 |  |  
    | Number of Options |  |  | 25,000,000 |  |  |  | 27,200,000 |  |  |  | 250,000 |  |  
    | Weighted Average Remaining Contractual Life (years) |  |  | 4.42 |  |  |  | 4.67 |  |  |  | 4.98 |  |  
    | Weighted Average Stock Price |  | $ | 0.19 |  |  | $ | 0.10 |  |  | $ | 0.18 |  |  
    | Number of Options Exercisable |  |  | 25,000,000 |  |  |  | 27,200,000 |  |  |  | 250,000 |  |  
    | Weighted Average Contractual Life (years) |  |  | 5 |  |  |  | 5 |  |  |  | 5 |  |  
    | Weighted Average Exercise Price |  | $ | 0.19 |  |  | $ | 0.10 |  |  | $ | 0.18 |  |  | 
| Warrant activity | 
    |  |  |  | Warrants |  |  |  | Weighted
                                         Average Price |  |  |  | Weighted
                                         Average Fair Value |  |  
    | Outstanding, April 30, 2012 |  |  |  |  |  | $ |  |  |  | $ |  |  |  
    | Issued |  |  | 59,433,600 |  |  |  | 0.125 |  |  |  | 0.064 |  |  
    | Exercised |  |  |  |  |  |  |  |  |  |  |  |  |  
    | Outstanding, April 30, 2013 |  |  | 59,433,600 |  |  |  | 0.125 |  |  |  | 0.064 |  |  
    | Issued |  |  |  |  |  |  |  |  |  |  |  |  |  
    | Exercised |  |  | (1,768,000 | ) |  |  |  |  |  |  |  |  |  
    | Outstanding, April 30, 2014 |  |  | 57,665,600 |  |  |  | 0.18 |  |  |  | 0.065 |  |  
    | Issued |  |  | 15,854,308 |  |  |  |  |  |  |  |  |  |  
    | Exercised |  |  | (550,000 | ) |  |  |  |  |  |  |  |  |  
    | Outstanding, April 30, 2015 |  |  | 72,969,908 |  |  |  |  |  |  |  |  |  |  
    | Exercisable, April 30, 2015 |  |  | 72,969,908 |  |  | $ | 0.17 |  |  | $ | 0.075 |  |  | 
| Schedule of warrants outstanding and exercisable | 
    | Range of Exercise Prices |  | Number of Warrant
    Shares Exercisable at 04/30/2015 |  |  | Weighted Average
    Remaining Contractual Life |  |  | Exercisable Weighted
    Average Exercise Price |  |  
    | $0.075, $0.11, $0.12, $0.18 and $0.25 |  |  | 72,969,908 |  |  |  | 2.86 |  |  |  | 0.17 |  |  
    |  |  |  |  |  |  |  |  |  |  |  |  |  |  
    | Five Year Term    -    $0.075 |  |  | 1,056,000 |  |  |  | 2.45 |  |  |  |  |  |  
    | Five Year Term    -     $0.12 |  |  | 18,347,508 |  |  |  | 2.75 |  |  |  |  |  |  
    | Five Year Term    -    $0.18 |  |  | 19,811,200 |  |  |  | 2.67 |  |  |  |  |  |  
    | Five Year Term    -    $0.25 |  |  | 18,755,200 |  |  |  | 2.68 |  |  |  |  |  |  
    | Five Year Term    -    $0.11 |  |  | 10,000,000 |  |  |  | 4.90 |  |  |  |  |  |  
    | Nine Month Term -    $0.11 |  |  | 5,000,000 |  |  |  | 0.67 |  |  |  |  |  |  
    |  |  |  | 72,969,908 |  |  |  |  |  |  |  |  |  |  |