Note 5 - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator for basic and diluted earnings per share - net income	$ 2,098	$ 1,934	$ 4,363	$ 4,070
Denominator for basic earnings per share - weighted average shares outstanding (in shares)	3,383,109	3,333,018	3,376,445	3,327,384
Effect of dilutive securities - employee stock options (in shares)	8,766	13,515	8,389	12,734
Denominator for diluted earnings per share - adjusted weighted average shares outstanding (in shares)	3,391,875	3,346,533	3,384,834	3,340,118
Earnings per share - basic (in dollars per share)	$ 0.62	$ 0.58	$ 1.29	$ 1.22
Earnings per share - diluted (in dollars per share)	$ 0.62	$ 0.58	$ 1.29	$ 1.22