Note 7 - Line of Credit (Details Textual) - Revolving Credit Facility [Member] - USD ($)
Mar. 31, 2022
Mar. 31, 2021
Jun. 15, 2018
Line of Credit Facility, Maximum Borrowing Capacity     $ 400,000
Debt Instrument, Interest Rate, Stated Percentage 5.37% 3.87%  
Short-Term Debt, Total $ 334,760 $ 226,413