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Schedule of Share-based Payment Award, Stock Options, Valuation Assumption (Details)
3 Months Ended
Jul. 31, 2021
Jul. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Dividend rate 0.00% 0.00%
Risk-free interest rate   0.10%
Expected life (in years) 4 months 24 days  
Expected volatility 154.00% 101.80%
Minimum [Member]    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Risk-free interest rate 0.05%  
Expected life (in years)   1 year
Maximum [Member]    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Risk-free interest rate 0.06%  
Expected life (in years)   1 year 4 months 24 days