Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Weighted average common shares outstanding - basic (in shares)	10,220,853	10,385,017
Unvested shares of restricted stock and employee stock options (in shares)		29,313
Weighted average common shares and common share equivalents outstanding - diluted (in shares)	10,220,853	10,414,330
Average number of potentially dilutive securities excluded from calculation (in shares)	685,667	284,240