Note 2 - Business Combinations - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			12 Months Ended
		Jul. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock issued to acquire Great State Bank				$ 15,495
Goodwill			$ 3,257	$ 3,198
Great State Bank [Member]
Cash and cash equivalents		$ 25,761
Investment securities		19,401
Restricted equity securities		523
Loans		95,108
Allowance for loan losses
Property and equipment	[1]	1,396
Intangible assets		2,425
Accrued interest receivable		334
Other assets		448
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Total		145,396
Deposits		130,551
Borrowings		2,000
Accrued interest payable		40
Other liabilities		369
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Total		132,960
Net assets acquired		12,436
Elimination of Company’s existing investment in Great State Bank		198
Stock issued to acquire Great State Bank		15,495
Goodwill		3,257
Great State Bank [Member] | Reported Value by Acquiree [Member]
Cash and cash equivalents		25,761
Investment securities		19,630
Restricted equity securities		523
Loans		97,549
Allowance for loan losses		(1,436)
Property and equipment	[1]	1,207
Intangible assets
Accrued interest receivable		334
Other assets		599
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Total		144,167
Deposits		129,611
Borrowings		2,000
Accrued interest payable		40
Other liabilities		352
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Total		132,003
Great State Bank [Member] | Fair Value Adjustments [Member]
Cash and cash equivalents
Investment securities	[2]	(229)
Restricted equity securities
Loans	[3]	(2,441)
Allowance for loan losses	[4]	1,436
Property and equipment	[1]	189
Intangible assets	[5]	2,425
Accrued interest receivable
Other assets	[6]	(151)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Total		1,229
Deposits	[7]	940
Borrowings
Accrued interest payable
Other liabilities	[8]	17
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Total		$ 957

[1] Estimated adjustment to Great State’s real property based upon third-party appraisals and the Company’s evaluation of equipment and other fixed assets.

[2] Reflects the opening fair value of securities portfolio, which was established as the new book basis of the portfolio.

[3] Reflects the fair value adjustment based on the Company's third party valuation report.

[4] Existing allowance for loan losses eliminated to reflect accounting guidance.

[5] Reflects the recording of the estimated core deposit intangible based on the Company's third party valuation report.

[6] Recording of deferred tax asset generated by the net fair value adjustments (tax rate = 21%).

[7] Estimated fair value adjustment to time deposits based on the Company's third party valuation report on deposits assumed.

[8] Reflects the fair value adjustment based on the Company's evaluation of acquired other liabilities.