Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Weighted average common shares outstanding - basic (in shares)	11,241,183	10,653,268	10,998,456	10,635,270
Unvested shares of restricted stock and employee stock options (in shares)	455,386	161,531	394,161	193,426
Weighted average common shares and common share equivalents outstanding - diluted (in shares)	11,696,569	10,814,799	11,392,617	10,828,696
Average number of potentially dilutive securities excluded from calculation because their effect was anti-dilutive during the period (in shares)	96,661	608,322	125,545	477,448