Note 1 - Summary of Significant Accounting Policies (Details Textual)	3 Months Ended		12 Months Ended
	May 31, 2021 USD ($)	Feb. 28, 2021 USD ($)	Nov. 30, 2021 USD ($)	Nov. 30, 2020 USD ($)	Feb. 29, 2020 USD ($)
Revenues, Total			$ 24,965,086	$ 22,409,123
Inventory Valuation Reserves, Ending Balance			2,525,743	1,703,374
Inventory Write-down			$ (638,633)	556,303
Accounts Receivable, Threshold Period On International Sales (Day)			180 days
Overdue Trade Receivables Interest Rate Percent of Account Balances Per Month			1.50%
Sales-type Lease, Lease Income, Total			$ 0	0
Lease, Cost, Total			$ 22,445	$ 23,121
Operating Lease, Weighted Average Remaining Lease Term (Month)			48 months
Operating Lease, Weighted Average Discount Rate, Percent			5.50%
Lessee, Finance Lease, Term of Contract (Month)			42 months
Lessee, Finance Lease, Discount Rate			4.77%
Finance Lease, Right-of-Use Asset, Amortization			$ 9,356
Effective Income Tax Rate Reconciliation, Debt Forgiveness, Paycheck Protection Program Under CARES Act			0.00%	8.80%
Contract with Customer, Liability, Revenue Recognized			$ 474,000	$ 89,000
Number of Operating Segments			3
Research and Development Expense, Total			$ 152,000	199,000
Advertising Expense			163,000	175,000
Operating Lease, Liability, Total			47,794	27,879
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset					$ 34,316
Operating Lease, Liability, Total					$ 34,316
Product [Member]
Contract with Customer, Liability, Revenue Recognized			$ 1,621,832	$ 0
Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)			3 years
Lessee, Operating Lease, Term of Contract (Month)			12 months
Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)			40 years
Lessor, Capital Lease, Term of Contract (Month)			36 months
Lessee, Operating Lease, Term of Contract (Month)			60 months
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number Of Major Customers			1	1
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Customer [Member]
Concentration Risk, Percentage			8.00%	18.00%
Estimated Costs To Complete Material Contract [Member]
Revenues, Total				$ 1,300,000
Estimated Costs On Uncompleted Contracts				2,800,000
Change in Accounting Method Accounted for as Change in Estimate [Member]
Revenues, Total	$ 1,200,000	$ 1,200,000
Inventory Valuation and Obsolescence [Member]
Inventory Valuation Reserves, Ending Balance				$ 681,000
Inventory Write-down			$ 543,000