Note 3 - Earnings Per Share - Computations of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Weighted average shares outstanding during the period in which basic earnings per share is calculated (in shares)									5,426,605	4,074,231
Dilutive effect of stock compensation (in shares)									63,742	58,359
Average outstanding shares on which diluted earnings per share is calculated (in shares)									5,490,347	4,132,590
Net income	$ 1,444	$ 1,632	$ 1,333	$ 573	$ 553	$ 1,721	$ 1,066	$ 763	$ 4,982	$ 4,103
BASIC EARNINGS PER SHARE (in dollars per share)	$ 0.27	$ 0.30	$ 0.24	$ 0.11	$ 0.11	$ 0.45	$ 0.28	$ 0.20	$ 0.92	$ 1.01
DILUTED EARNINGS PER SHARE (in dollars per share)	$ 0.26	$ 0.30	$ 0.24	$ 0.11	$ 0.11	$ 0.45	$ 0.27	$ 0.20	$ 0.91	$ 0.99