Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2024	Nov. 30, 2023	Nov. 30, 2024	Nov. 30, 2023
Income Statement [Abstract]
Net sales	$ 1,636,000	$ 1,567,000	$ 3,444,000	$ 3,281,000
Cost of sales	(1,199,000)	(1,242,000)	(2,720,000)	(2,541,000)
Gross profit	437,000	325,000	724,000	740,000
Operating expenses:
Selling, general and administrative	1,173,000	1,521,000	2,533,000	2,696,000
Research and development	257,000	412,000	554,000	883,000
Total operating expenses	1,430,000	1,933,000	3,087,000	3,579,000
Loss from operations	(993,000)	(1,608,000)	(2,363,000)	(2,839,000)
Other income:
Interest and dividend income	40,000	109,000	97,000	231,000
Total other income	40,000	109,000	97,000	231,000
Loss before income taxes	(953,000)	(1,499,000)	(2,266,000)	(2,608,000)
Benefit (provision) for income taxes	3,000	(8,000)		(31,000)
Net loss	$ (950,000)	$ (1,507,000)	$ (2,266,000)	$ (2,639,000)
Basic net loss per common share	$ (0.06)	$ (0.09)	$ (0.13)	$ (0.16)
Diluted net loss per common share	$ (0.06)	$ (0.09)	$ (0.13)	$ (0.16)
Weighted average number of common and common equivalent shares:
Basic	17,121,436	16,821,646	16,970,722	16,821,646
Diluted	17,121,436	16,821,646	16,970,722	16,821,646
Other comprehensive income (loss), net of tax:
Foreign currency translation	$ (4,000)		$ (10,000)	$ 6,000
Comprehensive loss	$ (954,000)	$ (1,507,000)	$ (2,276,000)	$ (2,633,000)