Note 4 - Loans and Allowance for Loan Losses - Risk Category of Commercial Loans by Class of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans receivable	$ 780,644	$ 777,052
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	223,506	216,360
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans receivable	64,553	61,694
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans receivable	127,105	117,188
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	31,848	37,478
Commercial and Industrial Portfolio Segment [Member]
Loans receivable	114,755	113,243
Commercial Portfolio Segment [Member]
Loans receivable	338,261	329,603
Pass [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans receivable	53,613	50,474
Pass [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans receivable	119,130	115,170
Pass [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable	31,848	37,321
Pass [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans receivable	99,986	92,417
Pass [Member] | Commercial Portfolio Segment [Member]
Loans receivable	304,577	295,382
Criticized [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans receivable	7,653	7,724
Criticized [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans receivable
Criticized [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable
Criticized [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans receivable	989	6,536
Criticized [Member] | Commercial Portfolio Segment [Member]
Loans receivable	8,642	14,260
Classified [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans receivable	3,287	3,496
Classified [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans receivable	7,975	2,018
Classified [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable		157
Classified [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans receivable	13,780	14,290
Classified [Member] | Commercial Portfolio Segment [Member]
Loans receivable	$ 25,042	$ 19,961