Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Weighted average common shares outstanding - basic (in shares)	10,695,867	10,496,188	10,655,469	10,422,851
Unvested shares of restricted stock and employee stock options (in shares)	168,673	296,102	185,175	271,500
Weighted average common shares and common share equivalents outstanding - diluted (in shares)	10,864,540	10,792,290	10,840,644	10,694,351
Average number of potentially dilutive securities excluded from calculation (in shares)	518,145	237,545	491,014	283,894