• Filing Date: 2019-07-11
  • Form Type: 10-K
  • Description: Annual report
v3.19.2
Intangibles and Other Assets (Tables)
12 Months Ended
Apr. 30, 2019
Schedule of Finite-Lived Intangible Assets [Table Text Block]
      April 30, 2019  
            Accumulated        
      Cost     Amortization     Net  
  Patents $  461,637   $  (417,609 ) $  44,028  
  Trademarks   175,100         175,100  
  Other assets   5,667         5,667  
    $  642,404   $  (417,609 ) $  224,795  
 
      April 30, 2018  
            Accumulated        
      Cost     Amortization     Net  
  Patents $  461,637   $  (411,788 ) $  49,849  
  Trademarks   165,462         165,462  
  Other assets   5,751         5,751  
    $  632,850   $  (411,788 ) $  221,062  
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
  Years ended April 30,      
  2020 $  4,248  
  2021   4,248  
  2022   4,248  
  2023   4,248  
  2024   4,248  
  Thereafter   22,788  
    $  44,028