Annual report pursuant to Section 13 and 15(d)

Share Based Awards - Assumptions used for estimating fair value of options (Details)

v3.21.2
Share Based Awards - Assumptions used for estimating fair value of options (Details) - Assumptions used - fair value of options - $ / shares
12 Months Ended
Apr. 30, 2021
Apr. 30, 2020
Exercise price, minimum $ 2.01 $ 0.82
Exercise price, maximum 3.95 2.10
Stock price on date of grant, minimum 2.01 0.82
Stock price on date of grant, maximum $ 3.95 $ 2.10
Expected volatility, minimum 88.60%  
Expected volatility, maximum 91.44% 75.00%
Risk-free interest rate, minimum 0.38% 1.59%
Risk-free interest rate, maximum 1.66% 1.74%
Expected term, minimum 5 years 10 months 13 days 5 years
Expected term, maximum 10 years 10 years
Expected dividends