Note 14 - Financial Instruments and Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring and Non Recurring Basis (Details) - USD ($)		Dec. 31, 2019	Dec. 31, 2018
Available-for-sale securities, fair market value		$ 190,088,000	$ 206,712,000
Equity Securities		3,297,000	3,106,000
Fair Value, Nonrecurring [Member] | Consumer Portfolio Segment [Member]
Impaired loans		248,000	14,000
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Consumer Portfolio Segment [Member]
Impaired loans		0	0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Consumer Portfolio Segment [Member]
Impaired loans		0	0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Consumer Portfolio Segment [Member]
Impaired loans		248,000	14,000
US Government Agencies Debt Securities [Member]
Available-for-sale securities, fair market value		31,729,000	44,106,000
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member]
Available-for-sale securities, fair market value		31,729,000	44,106,000
US Government Agencies Debt Securities [Member] | Fair Value, 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, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		31,729,000	44,106,000
US Government Agencies Debt Securities [Member] | Fair Value, 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		1,614,000	2,012,000
Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Available-for-sale securities, fair market value		1,614,000	2,012,000
Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		1,614,000	2,012,000
Collateralized Mortgage Obligations [Member] | Fair Value, 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		90,571,000	93,237,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Available-for-sale securities, fair market value		90,571,000	93,237,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, 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, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		90,571,000	93,237,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, 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		6,395,000	8,673,000
SBA Pool [Member] | Fair Value, Recurring [Member]
Available-for-sale securities, fair market value		6,395,000	8,673,000
SBA Pool [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
SBA Pool [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		6,395,000	8,673,000
SBA Pool [Member] | Fair Value, 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		18,968,000	20,587,000
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Available-for-sale securities, fair market value		18,968,000	20,587,000
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		18,968,000	20,587,000
Corporate Debt Securities [Member] | Fair Value, 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		40,811,000	38,097,000
Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Available-for-sale securities, fair market value		40,811,000	38,097,000
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale securities, fair market value		0	0
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale securities, fair market value		40,811,000	38,097,000
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale securities, fair market value		0	0
Mutual Fund [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	3,297,000	3,106,000
Mutual Fund [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Equity Securities	[1]	3,297,000	3,106,000
Mutual Fund [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Equity Securities	[1]	0	0
Mutual Fund [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Equity Securities	[1]	0	0
Land Loans [Member] | Fair Value, Nonrecurring [Member]
Impaired loans		175,000	226,000
Land Loans [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Impaired loans		0	0
Land Loans [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Impaired loans		0	0
Land Loans [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans		$ 175,000	$ 226,000

[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 accounting standard.