Note 6 - Earnings Per Share - Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income	$ 2,541	$ 1,837	$ 4,605	$ 3,410
Basic earnings per share (in dollars per share)	$ 0.51	$ 0.38	$ 0.93	$ 0.70
Diluted earnings per share (in dollars per share)	$ 0.49	$ 0.36	$ 0.89	$ 0.67
Basic shares (in shares)	5,001	4,857	4,956	4,849
Diluted shares (in shares)	5,180	5,047	5,173	5,057