Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Schedule of Stock Options Activity (Details)

v3.21.2
Stockholders' Equity - Schedule of Stock Options Activity (Details) - USD ($)
12 Months Ended
Apr. 30, 2021
Apr. 30, 2020
Apr. 30, 2021
Apr. 30, 2020
Number of Shares        
Exercised (in shares)     (52,778) (363,334)
Balance Outstanding, April 30, 2021 (in shares) 1,214,473   1,214,473  
Exercisable, April 30, 2021 (in shares) 1,032,411 2,734,899 1,032,411 2,734,899
Stock Incentive Plan and Stock Option Grants to Employees and Directors        
Number of Shares        
Balance Outstanding, April 30, 2020 (in shares)     2,740,539  
Granted (in shares)     0  
Exercised (in shares)     (1,442,241)  
Forfeited (in shares)     (11,916)  
Expired (in shares)     (71,909)  
Balance Outstanding, April 30, 2021 (in shares) 1,214,473 2,740,539 1,214,473 2,740,539
Exercisable, April 30, 2021 (in shares) 1,032,411   1,032,411  
Weighted Average Exercise Price        
Balance Outstanding, April 30, 2020 (in dollars per share)     $ 4.62  
Granted (in dollars per share)     0  
Exercised (in dollars per share)     10.71  
Forfeited (in dollars per share)     5.56  
Expired (in dollars per share)     3.98  
Balance Outstanding, April 30, 2021 (in dollars per share) $ 6.24 $ 4.62 6.24 $ 4.62
Exercisable, April 30, 2021 (in dollars per share) $ 6.26   $ 6.26  
Weighted Average Remaining Contractual Term        
Balance Outstanding, April 30, 2020 1 year 10 months 17 days 1 year 11 months 19 days    
Balance Outstanding, April 30, 2021 1 year 10 months 17 days 1 year 11 months 19 days    
Exercisable, April 30, 2021     1 year 9 months 10 days  
Aggregate Intrinsic Value        
Balance Outstanding, April 30, 2020     $ 9,146,198  
Balance Outstanding, April 30, 2021 $ 204,719 $ 9,146,198 204,719 $ 9,146,198
Exercisable, April 30, 2021 $ 173,852   $ 173,852