Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Weighted average common shares outstanding–basic (in shares)	11,962,679	11,886,005	11,241,183	10,755,729	10,725,662	10,695,867	10,653,268	10,617,271	11,461,399	10,673,017
Unvested shares of restricted stock and employee stock options (in shares)									318,513	189,521
Weighted average common shares and common share equivalents outstanding–diluted (in shares)	12,122,099	12,212,317	11,696,569	11,088,664	10,928,220	10,864,540	10,814,799	10,842,592	11,779,912	10,862,538
Average number of potentially dilutive securities excluded from calculation (in shares)									140,079	478,024