SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($)	12 Months Ended
	May 31, 2021	May 31, 2020	Jan. 22, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Retained Earnings (Accumulated Deficit)	$ (28,394,768)	$ (21,925,732)
Shelf Registration Statement, Maximum Authorized Common Stock Issuance, Value			$ 15,000,000
Stock Issued During Period, Shares, New Issues (in Shares)	158,889
Proceeds from Issuance of Common Stock	$ 1,011,475	10,232,857
Proceeds from Stock Options Exercised	102,255	223,534
Cash, Uninsured Amount	$ 3,767,000
Concentration Risk, Percentage	100.00%
Other Receivables, Gross, Current	$ 2,292,466	1,836,852
Property, Plant and Equipment, Net	$ 310,520	279,379
Threshold Period Past Due for Write-off of Trade Accounts Receivable	90 days
Accounts Receivable, Credit Loss Expense (Reversal)	$ 766,434	(2,129)
Increase (Decrease) in Prepaid Supplies	370,000	1,000,000
Inventory Valuation Reserves	1,617,000	67,000
Inventory, LIFO Reserve	1,502,675
Depreciation, Depletion and Amortization	104,715	105,299
Amortization of Intangible Assets	$ 33,552	23,873
Equity Method Investment, Ownership Percentage	6.00%
Research and Development Expense	$ 2,410,506	1,910,209
Deferred Tax Assets, Valuation Allowance	5,590,000	3,488,000
Deferred Tax Assets, Gross	5,590,000	3,488,000
Advertising Expense	10,070	174
Operating Lease, Right-of-Use Asset	1,553,081	$ 1,711,510
Operating Lease, Liability	$ 1,619,514
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares)	2,081,366	1,789,251
ATM Agreement [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Proceeds from Issuance of Common Stock	$ 1,177,394
Proceeds from Stock Options Exercised	$ 1,011,475
Series A Preferred Stock [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion (in Shares)	321,429
Accounts Receivable [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Accounts Receivable, Credit Loss Expense (Reversal)	$ 837,415
Distribution Rights [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	18 years
Purchased Technology Rights [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Patents [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years
Minimum [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Share Price (in Dollars per share)	$ 7.06
Property, Plant and Equipment, Useful Life	5 years
Maximum [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Share Price (in Dollars per share)	$ 7.79
Property, Plant and Equipment, Useful Life	10 years
Retained Earnings [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Retained Earnings (Accumulated Deficit)	$ 28,400,000
5% Convertible Preferred Stock [Member] | Series A Preferred Stock [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Preferred Stock, Shares Outstanding (in Shares)	0	321,429
MEXICO
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Inventory, Gross	$ 803,000	$ 613,000
Property, Plant and Equipment, Net	$ 25,000	$ 31,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Two Distributors [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage	60.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Three Distributors [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage		57.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Distributors [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage	33.00%	26.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Two Distributors [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage	73.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Three Distributors [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage		80.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Distributors in China [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage	41.00%
Supplier Concentration Risk [Member] | Cost of Goods and Service, Product and Service Benchmark [Member] | One Vendor [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Concentration Risk, Percentage	58.00%	59.00%
Accounting Standards Update 2016-02 [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) [Line Items]
Operating Lease, Right-of-Use Asset	$ 1,942,999
Operating Lease, Liability	$ 1,980,970