Geographic Information (Tables)

3 Months Ended

Aug. 31, 2017

Geographic Information Disclosure [Abstract]

Revenue from External Customers by Geographic Areas [Table Text Block]

	Three Months Ended August 31,
	2017		2016
Revenues from sales to unaffiliated customers:
United States	$	187,000	$	226,000
Asia		620,000		575,000
Europe		532,000		554,000
South America		75,000		16,000
Middle East		26,000		38,000
Other		4,000		1,000
	$	1,444,000	$	1,410,000