Note 2 - Accounts Receivable - Allowance for Doubtful Accounts (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Allowance for credit losses, beginning of year	$ 62,000	$ 61,376
Additions	46,934	87,627
Write-off	(40,314)	(87,003)
Accounts receivable allowance for credit losses, end of year	$ 68,620	$ 62,000