Note 6 - Inventories
 6 Months Ended
Sep. 30, 2018
Notes to Financial Statements  
Inventory Disclosure [Text Block]

 
NOTE
6.
INVENTORIES

     Inventories are shown in the following table:
 
   
Sept. 30,
2018
    
March 31,
2018
  
Raw materials
   $
1,103,638
     $
1,084,030
  
Work in process
    
1,871,388
      
1,828,492
  
Finished goods
    
600,937
      
737,917
  
Total inventories
   $
3,575,963
     $
3,650,439