Annual report pursuant to Section 13 and 15(d)

Summary of activity under the Plan (Details)

v3.22.2
Summary of activity under the Plan (Details) - Options 1 [Member] - USD ($)
12 Months Ended
Apr. 30, 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 3,694,142 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 1,681,000 600,000  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value $ 2.58 $ 3.63  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period 150,000  
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price $ 2.49  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested Options Forfeited, Number of Shares (34,333)  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price $ 2.11  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term 8 years 6 months 21 days 8 years 8 months 4 days  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value $ 1,407,545 $ 4,943,870  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (150,000)  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number 2,094,642    
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price $ 1.90    
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term 7 years 10 months 28 days    
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value $ 1,058,620