XML 21 R21.htm IDEA: XBRL DOCUMENT v3.19.3
Significant Accounting Policies (Details) - Inventories - USD ($)
Aug. 31, 2019
May 31, 2019
Inventories [Abstract]    
Raw materials $ 1,217,000 $ 1,208,000
Work in progress 831,000 771,000
Finished products 158,000 172,000
Total $ 2,206,338 $ 2,151,090