Note 2 - Significant Accounting Policies - Schedule of Earnings Per Share (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income applicable to Common Stockholders	$ 800,206	$ 408,215	$ 800,206	$ 408,215
Weighted average Common Stock outstanding, basic (in shares)	19,383,000	19,489,000	19,383,000	19,489,000
Warrants to purchase Common Stock (in shares)			286,000	153,000
Weighted average Common Stock outstanding, diluted (in shares)	19,669,000	19,642,000	19,669,000	19,642,000
Basic (in dollars per share)	$ 0.04	$ 0.02	$ 0.04	$ 0.02
Diluted (in dollars per share)	$ 0.04	$ 0.02	$ 0.04	$ 0.02