Note 6 - Valuation Accounts - Summary of Valuation and Allowance Accounts (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Balance, Beginning of Year	$ 506,153
Balance, End of Year	515,199	$ 506,153
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Balance, Beginning of Year	123,165	55,212
Net Charged to Costs and Expenses	96,000	89,613
Transfers
Net Write-off	(13,643)	(21,660)
Balance, End of Year	205,522	123,165
SEC Schedule, 12-09, Reserve, Legal [Member]
Balance, Beginning of Year	506,153	374,153
Net Charged to Costs and Expenses	132,000	132,000
Transfers
Net Write-off	(122,954)
Balance, End of Year	$ 515,199	$ 506,153