CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Net sales	$ 1,596,408	$ 1,500,791	$ 2,790,823	$ 2,773,661
Cost of sales	(1,127,536)	(1,092,731)	(1,954,647)	(2,028,378)
Gross profit	468,872	408,060	836,176	745,283
Operating Expenses:
Selling, general and administrative	553,761	512,592	1,060,958	912,820
Research and development	404,854	381,405	775,320	773,186
Total operating expenses	958,615	893,997	1,836,278	1,686,006
Loss from operations	(489,743)	(485,937)	(1,000,102)	(940,723)
Other Income (Expense):
Dividend and interest income	4,488	8,693	8,551	11,786
Interest expense	(5)		(5)	(47)
Total other income	4,483	8,693	8,546	11,739
Net loss	$ (485,260)	$ (477,244)	$ (991,556)	$ (928,984)
Basic net loss per common share (in Dollars per share)	$ (0.05)	$ (0.05)	$ (0.10)	$ (0.10)
Diluted net loss per common share (in Dollars per share)	$ (0.05)	$ (0.05)	$ (0.10)	$ (0.10)
Weighted average number of common and common equivalent shares:
Basic (in Shares)	9,817,363	9,061,617	9,780,713	8,995,575
Diluted (in Shares)	9,817,363	9,061,617	9,780,713	8,995,575
Net loss	$ (485,260)	$ (477,244)	$ (991,556)	$ (928,984)
Other comprehensive loss, net of tax:
Foreign currency translation	(1,643)	(4,480)	(5,085)	(5,806)
Comprehensive loss	$ (486,903)	$ (481,724)	$ (996,641)	$ (934,790)