CONSOLIDATED BALANCE SHEETS - USD ($)	May 31, 2021	May 31, 2020
Current Assets:
Cash and cash equivalents	$ 4,199,311	$ 8,641,027
Accounts receivable, less allowance for doubtful accounts of $837,415 and $70,981 as of May 31, 2021 and 2020, respectively	1,455,051	1,765,871
Inventories, net	3,206,255	2,850,836
Prepaid expenses and other	370,290	1,509,083
Total current assets	9,230,907	14,766,817
Property and equipment, net of accumulated depreciation and amortization of $1,972,357 and $1,867,643 as of May 31, 2021 and 2020, respectively	310,520	279,379
Right of use assets, net of accumulated amortization of $469,077 and $231,489 as of May 31, 2021 and 2020, respectively	1,553,081	1,711,510
Investments	165,324	165,324
Intangible assets, net of accumulated amortization of $126,769 and $496,124 as of May 31, 2021 and 2020, respectively	294,830	168,655
Other assets	264,151	168,193
Total Assets	11,818,813	17,259,878
Current Liabilities:
Accounts payable and accrued expenses	583,380	986,711
Accrued compensation	388,896	278,627
Lease liability, current portion	327,944	211,809
Total current liabilities	1,300,220	1,477,147
Lease liability, net of current portion	1,291,570	1,569,678
Total Liabilities	2,591,790	3,046,825
Commitments and contingencies (Notes 1 and 9)
Shareholders' Equity:
Preferred stock, Series A 5% convertible, $0.08 par value, 571,429 shares authorized, none issued and outstanding at May 31, 2021 and 321,429 issued and outstanding at May 31, 2020 and Preferred stock, undesignated, no par value, 4,428,571 shares authorized, none issued and outstanding at May 31, 2021 and 2020		25,714
Common stock, $0.08 par value, 25,000,000 shares authorized, 12,307,157 and 11,740,089 issued and outstanding at May 31, 2021 and 2020, respectively	984,571	939,205
Additional paid-in-capital	36,685,176	35,213,707
Accumulated other comprehensive loss	(47,956)	(39,841)
Accumulated deficit	(28,394,768)	(21,925,732)
Total Shareholders' Equity	9,227,023	14,213,053
Total Liabilities and Shareholders' Equity	11,818,813	17,259,878
5% Convertible Preferred Stock [Member] | Series A Preferred Stock [Member]
Shareholders' Equity:
Preferred stock, Series A 5% convertible, $0.08 par value, 571,429 shares authorized, none issued and outstanding at May 31, 2021 and 321,429 issued and outstanding at May 31, 2020 and Preferred stock, undesignated, no par value, 4,428,571 shares authorized, none issued and outstanding at May 31, 2021 and 2020		25,714
Preferred Stock [Member]
Shareholders' Equity:
Preferred stock, Series A 5% convertible, $0.08 par value, 571,429 shares authorized, none issued and outstanding at May 31, 2021 and 321,429 issued and outstanding at May 31, 2020 and Preferred stock, undesignated, no par value, 4,428,571 shares authorized, none issued and outstanding at May 31, 2021 and 2020