Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Weighted average common shares outstanding–basic (in shares)	10,755,729	10,617,271
Unvested shares of restricted stock and employee stock options (in shares)	332,935	225,321
Weighted average common shares and common share equivalents outstanding–diluted (in shares)	11,088,664	10,842,592
Average number of potentially dilutive securities excluded from calculation (in shares)	154,429	318,574