SELECTED QUARTERLY CONSOLIDATED FINANCIAL DATA (Details) - USD ($)	3 Months Ended								12 Months Ended
	May 31, 2022	Feb. 28, 2022	Nov. 30, 2021	Aug. 31, 2021	May 31, 2021	Feb. 28, 2021	Nov. 30, 2020	Aug. 31, 2020	May 31, 2022	May 31, 2021	May 31, 2020
SELECTED QUARTERLY CONSOLIDATED FINANCIAL DATA (UNAUDITED)
Net sales	$ 20,289,000	$ 15,283,000	$ 9,611,000	$ 5,646,000	$ 7,638,000	$ 5,267,000	$ 1,683,000	$ 2,012,000	$ 50,829,000	$ 16,600,000	$ 22,291,000
Gross profit	10,468,000	6,397,000	4,519,000	2,281,000	3,534,000	1,894,000	377,000	227,000	23,665,000	6,032,000	8,371,000
Net income (loss)	$ 5,794,000	$ 2,243,000	$ 717,000	$ 696,000	$ 567,000	$ (735,000)	$ (1,966,000)	$ 107,000	$ 9,450,000	$ (2,027,000)	$ (2,802,000)
Net income (loss) per share basic	$ 0.21	$ 0.08	$ 0.03	$ 0.03	$ 0.02	$ (0.03)	$ (0.08)	$ 0.00	$ 0.36	$ (0.09)	$ (0.12)
Net income (loss) per share diluted	$ 0.20	$ 0.08	$ 0.03	$ 0.03					$ 0.34	$ (0.09)	$ (0.12)