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Geographic Information (Details) - USD ($)
9 Months Ended
Feb. 28, 2018
May 31, 2017
Geographic Information (Details) [Line Items]    
Property, Plant and Equipment, Net $ 318,681 $ 331,857
Geographic Concentration Risk [Member]    
Geographic Information (Details) [Line Items]    
Concentration Risk, Percentage 10.00%  
MEXICO    
Geographic Information (Details) [Line Items]    
Inventory, Gross $ 537,000 467,000
Property, Plant and Equipment, Net $ 20,000 $ 15,000