Note 3 - Available-for-sale Securities - Investment Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized cost, due within 5 years	$ 11,299	$ 7,823
Amortized cost, due after 5 years through 10 years	26,772	30,226
Amortized cost, due after 10 years	11,889	10,811
Available-for-sale securities, amortized cost	49,960	48,860
Fair value, due within 5 years	11,539	7,961
Fair value, due after 5 years through 10 years	25,744	29,497
Fair value, due after 10 years	11,979	10,859
Fair value, total	49,262	48,317
Available-for-sale securities	49,262	48,317
Corporate Debt Securities [Member]
Amortized cost, due within 5 years	4,014	4,018
Amortized cost, due after 5 years through 10 years	14,000	14,000
Amortized cost, due after 10 years
Available-for-sale securities, amortized cost	18,014	18,018
Fair value, due within 5 years	4,274	4,151
Fair value, due after 5 years through 10 years	13,016	13,162
Fair value, due after 10 years
Fair value, total	17,290	17,313
Available-for-sale securities	17,290	17,313
Subordinated Notes [Member]
Amortized cost, due within 5 years	2,000
Amortized cost, due after 5 years through 10 years	7,036	9,022
Amortized cost, due after 10 years
Available-for-sale securities, amortized cost	9,036	9,022
Fair value, due within 5 years	2,003
Fair value, due after 5 years through 10 years	7,002	9,204
Fair value, due after 10 years
Fair value, total	9,005	9,204
Available-for-sale securities	9,005	9,204
SBA Loan Pools [Member]
Amortized cost, due within 5 years	1,921
Amortized cost, due after 5 years through 10 years	3,706	5,157
Amortized cost, due after 10 years
Available-for-sale securities, amortized cost	5,627	5,157
Fair value, due within 5 years	1,899
Fair value, due after 5 years through 10 years	3,668	5,115
Fair value, due after 10 years
Fair value, total	5,567	5,115
Available-for-sale securities	5,567	5,115
US States and Political Subdivisions Debt Securities [Member]
Amortized cost, due within 5 years
Amortized cost, due after 5 years through 10 years	564
Amortized cost, due after 10 years
Available-for-sale securities, amortized cost	564
Fair value, due within 5 years
Fair value, due after 5 years through 10 years	567
Fair value, due after 10 years
Fair value, total	567
Available-for-sale securities	567
Available-for-sale Securities with Single Maturity Dates [Member]
Amortized cost, due within 5 years	7,935	4,018
Amortized cost, due after 5 years through 10 years	25,306	28,179
Amortized cost, due after 10 years
Available-for-sale securities, amortized cost	33,241	32,197
Fair value, due within 5 years	8,176	4,151
Fair value, due after 5 years through 10 years	24,253	27,481
Fair value, due after 10 years
Fair value, total	32,429	31,632
Available-for-sale securities	32,429	31,632
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost, due within 5 years	3,364	3,805
Amortized cost, due after 5 years through 10 years	1,466	2,047
Amortized cost, due after 10 years	11,889	10,811
Available-for-sale securities, amortized cost	16,719	16,663
Fair value, due within 5 years	3,363	3,810
Fair value, due after 5 years through 10 years	1,491	2,016
Fair value, due after 10 years	11,979	10,859
Fair value, total	16,833	16,685
Available-for-sale securities	$ 16,833	$ 16,685