2. REVENUE (Details 2) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Net sales	$ 16,600	$ 22,291	$ 21,056
Products and Services Transferred at a Point in Time
Net sales	15,009	19,948	18,473
Services Transferred over Time
Net sales	$ 1,591	$ 2,343	$ 2,583