Note 15 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring and Non Recurring Basis (Details) - USD ($)		Dec. 31, 2018	Dec. 31, 2017
Available-for-sale securities, fair market value		$ 206,712,000	$ 179,248,000
Equity Securities		3,106,000	3,112,000
Other real estate owned		0	253,000
Fair Value, Measurements, Nonrecurring [Member]
Other real estate owned			253,000
Fair Value, Measurements, Nonrecurring [Member] | Consumer Portfolio Segment [Member]
Impaired loans		14,000	16,000
Fair Value, Measurements, Nonrecurring [Member] | Commercial Portfolio Segment [Member]
Impaired loans			302,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Other real estate owned			0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Consumer Portfolio Segment [Member]
Impaired loans		0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Portfolio Segment [Member]
Impaired loans			0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Other real estate owned			0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Consumer Portfolio Segment [Member]
Impaired loans		0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Portfolio Segment [Member]
Impaired loans			0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Other real estate owned			253,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Consumer Portfolio Segment [Member]
Impaired loans		14,000	16,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member]
Impaired loans			302,000
US Government Agencies Debt Securities [Member]
Available-for-sale securities, fair market value		44,106,000	29,972,000
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities, fair market value		44,106,000	29,972,000
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		44,106,000	29,972,000
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
Collateralized Mortgage Obligations [Member]
Available-for-sale securities, fair market value		2,012,000	2,593,000
Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities, fair market value		2,012,000	2,593,000
Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		2,012,000	2,593,000
Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, fair market value		93,237,000	93,067,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities, fair market value		93,237,000	93,067,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		93,237,000	93,067,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
SBA Pool [Member]
Available-for-sale securities, fair market value		8,673,000	11,850,000
SBA Pool [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities, fair market value		8,673,000	11,850,000
SBA Pool [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
SBA Pool [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		8,673,000	11,850,000
SBA Pool [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
Corporate Debt Securities [Member]
Available-for-sale securities, fair market value		20,587,000	18,789,000
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities, fair market value		20,587,000	18,789,000
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		20,587,000	18,789,000
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
Asset-backed Securities [Member]
Available-for-sale securities, fair market value		38,097,000	22,977,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities, fair market value		38,096,000	22,977,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		38,096,000	22,977,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member]
Equity Securities	[1]	3,106,000	3,112,000
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Equity Securities	[1]	3,106,000	3,112,000
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Equity Securities	[1]	0	0
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Equity Securities	[1]	0	0
Land Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Impaired loans		226,000	313,000
Land Loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Impaired loans		0	0
Land Loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Impaired loans		0	0
Land Loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans		$ 226,000	$ 313,000

[1] Effective January 1, 2018, the Company adopted ASU 2016-01, which requires equity securities with readily determinable fair values to be measured at fair value with changes in the fair value recognized through net income. See Note 1 for additional information on this new accounting standard.