Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Weighted average common shares outstanding - basic (in shares)	10,269,995	10,421,383	10,247,779	10,405,892
Unvested shares of restricted stock and employee stock options (in shares)	17,567	8,153		17,229
Weighted average common shares and common share equivalents outstanding - diluted (in shares)	10,287,562	10,429,536	10,247,779	10,423,121
Average number of potentially dilutive securities excluded from calculation (in shares)	631,392	657,969	722,538	501,964