Geographic Information (Tables)

6 Months Ended

Nov. 30, 2019

Geographic Information Disclosure [Abstract]

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

	Six Months Ended November 30,				Three Months Ended November 30,
	2019		2018		2019		2018
Revenues from sales to unaffiliated customers:
United States	$	224,000	$	282,000	$	109,000	$	140,000
Asia		1,460,000		1,320,000		797,000		672,000
Europe		717,000		914,000		416,000		522,000
South America		71,000		127,000		24,000		56,000
Middle East		309,000		131,000		241,000		111,000
Other		10,000		--		10,000		--
	$	2,791,000	$	2,774,000	$	1,597,000	$	1,501,000