Geographic Information (Details) - Financial information about foreign and domestic operations and export sales - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	$ 1,432,206	$ 1,165,080	$ 2,842,317	$ 2,452,073
UNITED STATES
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	172,000	218,000	398,000	405,000
Asia [Member]
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	716,000	419,000	1,292,000	852,000
Europe [Member]
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	464,000	473,000	1,018,000	1,092,000
South America [Member]
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	14,000	32,000	30,000	49,000
Middle East [Member]
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	53,000	$ 23,000	91,000	$ 54,000
Other Foreign [Member]
Geographic Information (Details) - Financial information about foreign and domestic operations and export sales [Line Items]
Net Sales	$ 13,000		$ 13,000