Quarterly report pursuant to Section 13 or 15(d)

Summary of activity under the Plan (Details)

v3.22.0.1
Summary of activity under the Plan (Details) - Options 1 [Member] - USD ($)
9 Months Ended 12 Months Ended
Jan. 31, 2022
Apr. 30, 2021
Apr. 30, 2020
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 3,714,975 2,197,475 1,597,475
Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price $ 2.17 $ 1.79 $ 1.10
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 1,656,000 600,000  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value $ 2.59 $ 3.63  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period 112,500  
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price $ 0.96  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares (26,000)  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price $ 2.12  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (112,500)  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term 8 years 8 months 19 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value $ 1,010,178    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number 1,897,142    
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price $ 2.13    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term 8 years 3 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value $ 687,111