2. REVENUE (Details 1) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Net sales	$ 22,291	$ 21,056	$ 29,555
United States
Net sales	13,544	13,468	8,446
Asia
Net sales	7,556	5,648	19,973
Europe
Net sales	$ 1,191	$ 1,940	$ 1,136