Note 10 - Stock Repurchase Program (Tables)
 6 Months Ended
Sep. 30, 2020
Notes Tables  
Schedule of Stock Repurchase Program [Table Text Block]
       
 
 
 
  
 
 
 
  
Total number of
    
Max. approximate
  
   
 
  
Total
    
Average
    
shares purchased
    
dollar value of
  
   
 
  
number
    
price
    
as part of publicly
    
shares that may
  
   
 
  
of shares
    
paid
    
announced
    
yet be purchased
  
Period
  
 
  
purchased
    
per share
    
program
    
under the program
 
July 1, 2020
 –
July 31, 2020
    
-
     $
-
      
-
     $
3,853,459
  
August 1, 2020
 –
August 31, 2020
    
-
     $
-
      
-
     $
3,853,459
  
September 1, 2020
 –
September 30, 2020
    
1,806
     $
50.62
      
1,806
     $
3,762,040
  
   
 
    
1,806
      
 
      
1,806