2. REVENUE (Details 2) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Net sales	$ 22,291	$ 21,056	$ 29,555
Products and Services Transferred at a Point in Time
Net sales	19,948	18,473	27,337
Services Transferred over Time
Net sales	$ 2,343	$ 2,583	$ 2,218