3. REVENUE (Details 1) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Net sales	$ 1,683	$ 6,874	$ 3,695	$ 12,407
United States
Net sales	970	2,627	2,011	7,684
Asia
Net sales	632	3,529	1,601	3,867
Europe
Net sales	$ 81	$ 718	$ 83	$ 856

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details