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Fair Value Measurements (Tables)
12 Months Ended
Apr. 30, 2021
Fair Value Disclosures [Abstract]  
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The Company determined the fair value using the Black-Scholes option pricing model with the following assumptions:

 

    April 30, 2021     April 30, 2020  
             
Dividend rate     0.0 %     0.0 %
Risk-free rate     0.01% - 0.02 %     0.17% - 0.19 %
Expected life (years)     0.2 - 0.6       1.2 - 1.6  
Expected volatility     149.8 %     81.8% - 112.7 %