Note 3 - Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Due in one year or less, available for sale, amortized cost	$ 7,289
Due in one year or less, available for sale, fair value	7,404
Due in one year or less, held to maturity, amortized cost	639
Due in one year or less, held to maturity, fair value	641
Due in over one to five years, available for sale, amortized cost	8,332
Due in over one to five years, available for sale, fair value	8,612
Due in over one to five years, held to maturity, amortized cost	6,802
Due in over one to five years, held to maturity, fair value	7,014
Due in over five to ten years, available for sale, amortized cost
Due in over five to ten years, available for sale, fair value
Due in over five to ten years, held to maturity, amortized cost	4,365
Due in over five to ten years, held to maturity, fair value	4,458
Agency mortgage-backed securities, residential, available for sale, amortized cost	92,965
Agency mortgage-backed securities, residential, available for sale, fair value	96,175
Agency mortgage-backed securities, residential, held to maturity, amortized cost	2
Agency mortgage-backed securities, residential, held to maturity, fair value	2
Total debt securities, available for sale, amortized cost	108,586	$ 104,650
Total debt securities, available for sale, fair value	112,191	105,318
Total debt securities, held to maturity, amortized cost	11,808	12,033
Total debt securities, held to maturity, fair value	$ 12,115	$ 12,404