Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Income Statement [Abstract]
Net sales	$ 1,567,000	$ 1,482,000	$ 3,281,000	$ 3,119,000
Cost of sales	(1,242,000)	(1,130,000)	(2,541,000)	(2,822,000)
Gross profit	325,000	352,000	740,000	297,000
Operating expenses:
Selling, general and administrative	1,521,000	1,556,000	2,696,000	3,210,000
Research and development	412,000	462,000	883,000	823,000
Total operating expenses	1,933,000	2,018,000	3,579,000	4,033,000
Loss from operations	(1,608,000)	(1,666,000)	(2,839,000)	(3,736,000)
Other income:
Interest and dividend income	109,000	41,000	231,000	41,000
Total other income	109,000	41,000	231,000	41,000
Loss before income taxes	(1,499,000)	(1,625,000)	(2,608,000)	(3,695,000)
Provision for income taxes	(8,000)	(1,000)	(31,000)	(3,000)
Net loss	$ (1,507,000)	$ (1,626,000)	$ (2,639,000)	$ (3,698,000)
Basic net loss per common share	$ (0.09)	$ (0.12)	$ (0.16)	$ (0.28)
Diluted net loss per common share	$ (0.09)	$ (0.12)	$ (0.16)	$ (0.28)
Weighted average number of common and common equivalent shares:
Basic	16,821,646	13,455,166	16,821,646	13,271,845
Diluted	16,821,646	13,455,166	16,821,646	13,271,845
Other comprehensive income (loss), net of tax:
Foreign currency translation		$ (9,000)	$ 6,000	$ (21,000)
Comprehensive loss	$ (1,507,000)	$ (1,635,000)	$ (2,633,000)	$ (3,719,000)