Note 5 - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Numerator for basic and diluted earnings per share - net income	$ 2,292	$ 2,220	$ 6,655	$ 6,290
Denominator for basic earnings per share - weighted average shares outstanding	3,391,471	3,343,011	3,381,491	3,332,650
Effect of dilutive securities - employee stock options	12,568	13,778	9,238	12,980
Denominator for diluted earnings per share - adjusted weighted average shares outstanding	3,404,039	3,356,789	3,390,729	3,345,630
Earnings per share - basic	$ 0.68	$ 0.66	$ 1.97	$ 1.89
Earnings per share - diluted	$ 0.67	$ 0.66	$ 1.96	$ 1.88