Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Schedule of Warrants (Details)

v3.21.2
Stockholders' Equity - Schedule of Warrants (Details) - Warrant - USD ($)
12 Months Ended
Apr. 30, 2021
Apr. 30, 2020
Apr. 30, 2021
Number of Shares      
Balance Outstanding, April 30, 2020 (in shares)     566,223
Granted (in shares)     0
Exercised (in shares)     (192,049)
Surrendered (in shares)     0
Expired (in shares)     0
Balance Outstanding, April 30, 2021 (in shares) 374,174 566,223 374,174
Exercisable, April 30, 2021 (in shares) 374,174   374,174
Weighted Average Exercise Price      
Balance Outstanding, April 30, 2020 (in dollars per share)     $ 6.22
Granted (in dollars per share)     0
Exercised (in dollars per share)     5.63
Surrendered (in dollars per share)     0
Expired (in dollars per share)     0
Balance Outstanding, April 30, 2021 (in dollars per share) $ 6.37 $ 6.22 6.37
Exercise price of options (in dollars per share) $ 6.37   $ 6.37
Weighted Average Remaining Contractual Term      
Balance Outstanding, April 30, 2020 1 year 10 months 24 days 3 years 2 months 1 day  
Balance Outstanding, April 30, 2021 1 year 10 months 24 days 3 years 2 months 1 day  
Exercisable, April 30, 2021 1 year 10 months 24 days    
Aggregate Intrinsic Value      
Balance Outstanding, April 30, 2020     $ 950,100
Balance Outstanding, April 30, 2021 $ 0 $ 950,100 0
Exercisable, April 30, 2021 $ 0   $ 0