Note 3 - Available-for-sale Securities - Investment Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Amortized cost, due within 5 years	$ 7,447	$ 7,823
Amortized cost, due after 5 years through 10 years	29,430	30,226
Amortized cost, due after 10 years	11,036	10,811
Available-for-sale securities, amortized cost	47,913	48,860
Fair value, due within 5 years	7,570	7,961
Fair value, due after 5 years through 10 years	27,883	29,497
Fair value, due after 10 years	11,171	10,859
Fair value, total	46,624	48,317
Corporate Debt Securities [Member]
Amortized cost, due within 5 years	4,017	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	18,017	18,018
Fair value, due within 5 years	4,116	4,151
Fair value, due after 5 years through 10 years	12,699	13,162
Fair value, due after 10 years
Fair value, total	16,815	17,313
Subordinated Notes [Member]
Amortized cost, due within 5 years
Amortized cost, due after 5 years through 10 years	9,029	9,022
Amortized cost, due after 10 years
Available-for-sale securities, amortized cost	9,029	9,022
Fair value, due within 5 years
Fair value, due after 5 years through 10 years	8,809	9,204
Fair value, due after 10 years
Fair value, total	8,809	9,204
SBA Loan Pools [Member]
Amortized cost, due within 5 years
Amortized cost, due after 5 years through 10 years	4,612	5,157
Amortized cost, due after 10 years	988
Available-for-sale securities, amortized cost	5,600	5,157
Fair value, due within 5 years
Fair value, due after 5 years through 10 years	4,553	5,115
Fair value, due after 10 years	976
Fair value, total	5,529	5,115
Available-for-sale Securities with Single Maturity Dates [Member]
Amortized cost, due within 5 years	4,017	4,018
Amortized cost, due after 5 years through 10 years	27,641	28,179
Amortized cost, due after 10 years	988
Available-for-sale securities, amortized cost	32,646	32,197
Fair value, due within 5 years	4,116	4,151
Fair value, due after 5 years through 10 years	26,061	27,481
Fair value, due after 10 years	976
Fair value, total	31,153	31,632
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost, due within 5 years	3,430	3,805
Amortized cost, due after 5 years through 10 years	1,789	2,047
Amortized cost, due after 10 years	10,048	10,811
Available-for-sale securities, amortized cost	15,267	16,663
Fair value, due within 5 years	3,454	3,810
Fair value, due after 5 years through 10 years	1,822	2,016
Fair value, due after 10 years	10,195	10,859
Fair value, total	$ 15,471	$ 16,685