CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	6 Months Ended
	Nov. 30, 2021	Nov. 30, 2020
Cash flows from operating activities:
Net loss	$ (2,667,855)	$ (3,610,492)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	68,668	64,435
Change in allowance on accounts receivable	(809,638)	410,161
Inventory reserve	181,825	11,943
Stock option expense	634,019	500,140
Amortization of right-of-use asset	126,039	115,025
Changes in assets and liabilities:
Accounts receivable	1,139,450	(256,059)
Inventories	42,229	(1,359,320)
Prepaid expenses and other	(726,460)	1,055,946
Reduction in lease liability	(117,321)	(102,677)
Other assets	114,570	(94,085)
Accounts payable and accrued expenses	997,327	271,386
Accrued compensation	285,431	113,379
Advance from customers	2,150,466
Net cash provided by (used in) operating activities	1,418,750	(2,880,218)
Cash flows from investing activities:
Increase in intangibles	(108,917)	(61,536)
Purchases of property and equipment	(18,212)	(61,566)
Net cash used in investing activities	(127,129)	(123,102)
Cash flows from financing activities:
Proceeds from sale of common stock, net	1,684,123
Proceeds from exercise of stock options	34,480	49,330
Net cash provided by financing activities	1,718,603	49,330
Effect of exchange rate changes in cash	(10,363)	(3,250)
Net increase (decrease) in cash and cash equivalents	2,999,861	(2,957,240)
Cash and cash equivalents at beginning of period	4,199,311	8,641,027
Cash and cash equivalents at end of period	7,199,172	5,683,787
Cash paid during the period for:
Income taxes	$ 10,646	$ 11,735