Note 7 - Fair Value Measurement - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financial assets
Securities available for sale	$ 53,594	$ 52,975	[1]
Reported Value Measurement [Member]
Financial assets
Cash and due from banks	34,755	18,229
Federal funds sold	132	42
Securities available for sale	53,594	52,975
Restricted equity securities	2,371	2,213
Loans held for sale	1,013	678
Loans, net	431,104	415,355
Bank owned life insurance	8,115	7,469
Accrued income	2,619	2,289
Financial liabilities
Total deposits	478,944	450,848
FHLB borrowings	11,361	8,000
Subordinated notes	7,247	7,224
Other borrowings	992	1,117
Accrued interest payable	508	386
Estimate of Fair Value Measurement [Member]
Financial assets
Cash and due from banks	34,755	18,239
Federal funds sold	132	42
Securities available for sale	53,594	52,975
Restricted equity securities	2,371	2,213
Loans held for sale	1,013	678
Loans, net	433,652	415,039
Bank owned life insurance	8,115	7,469
Accrued income	2,619	2,289
Financial liabilities
Total deposits	479,777	451,385
FHLB borrowings	11,386	8,031
Subordinated notes	7,954	8,012
Other borrowings	992	1,117
Accrued interest payable	508	386
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and due from banks	34,755	17,479
Federal funds sold	132	42
Securities available for sale
Restricted equity securities
Loans held for sale
Loans, net
Bank owned life insurance
Accrued income
Financial liabilities
Total deposits
FHLB borrowings
Subordinated notes
Other borrowings
Accrued interest payable
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Financial assets
Cash and due from banks		760
Federal funds sold
Securities available for sale	53,594	52,975
Restricted equity securities	2,371	2,213
Loans held for sale	1,013	678
Loans, net
Bank owned life insurance	8,115	7,469
Accrued income	2,619	2,289
Financial liabilities
Total deposits	479,777	451,385
FHLB borrowings	11,386	8,031
Subordinated notes	7,954	8,012
Other borrowings	992	1,117
Accrued interest payable	508	386
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and due from banks
Federal funds sold
Securities available for sale
Restricted equity securities
Loans held for sale
Loans, net	433,652	415,039
Bank owned life insurance
Accrued income
Financial liabilities
Total deposits
FHLB borrowings
Subordinated notes
Other borrowings
Accrued interest payable

[1] Derived from consolidated audited financial statements.