Note 6 - Concentrations (Details Textual)	3 Months Ended	12 Months Ended
Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2021
Revenue from Contract with Customer, Including Assessed Tax	$ 721,358	$ 569,093
Customer Concentration Risk [Member] \| Revenue Benchmark [Member] \| Three Customers [Member]
Concentration Risk, Number of Customers	2	2
Concentration Risk, Percentage	46.00%	54.00%
Customer Concentration Risk [Member] \| Revenue Benchmark [Member] \| Foreign Customers [Member]
Concentration Risk, Percentage	11.00%	4.00%
Revenue from Contract with Customer, Including Assessed Tax	$ 81,953	$ 24,666
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Three Customers [Member]
Concentration Risk, Number of Customers	3		3
Concentration Risk, Percentage	77.00%		81.00%

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details