Note 4 - Loan Receivables and Allowance for Loan and Lease Losses - Loan Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for loan and lease losses	$ (10,584)	$ (10,115)	$ (7,609)	$ (6,297)
Loans receivable, net	719,596	802,049
Business Activities Loans [Member]
Loans receivable, gross	730,180	812,164
Allowance for loan and lease losses	(10,584)	(10,115)
Loans receivable, net	719,596
Acquired Loans [Member]
Loans receivable, gross		812,164
Allowance for loan and lease losses		(10,115)
Loans receivable, net		802,049
Commercial Real Estate Portfolio Segment [Member]
Allowance for loan and lease losses	(4,485)	(3,789)	(1,866)	(2,212)
Commercial Real Estate Portfolio Segment [Member] | Business Activities Loans [Member]
Loans receivable, gross	282,378	314,414
Allowance for loan and lease losses	(4,485)	(3,789)
Commercial Real Estate Portfolio Segment [Member] | Acquired Loans [Member]
Loans receivable, gross		314,414
Residential Portfolio Segment [Member]
Allowance for loan and lease losses	(1,379)	(1,038)	(1,059)	(959)
Residential Portfolio Segment [Member] | Business Activities Loans [Member]
Loans receivable, gross	153,851	175,489
Allowance for loan and lease losses	(1,379)	(1,038)
Residential Portfolio Segment [Member] | Acquired Loans [Member]
Loans receivable, gross		175,489
Commercial Portfolio Segment [Member]
Allowance for loan and lease losses	(3,284)	(4,340)	(3,558)	(2,023)
Commercial Portfolio Segment [Member] | Business Activities Loans [Member]
Loans receivable, gross	144,297	173,875
Allowance for loan and lease losses	(3,284)	(4,340)
Commercial Portfolio Segment [Member] | Acquired Loans [Member]
Loans receivable, gross		173,875
Consumer Portfolio Segment [Member]
Allowance for loan and lease losses	(295)	(341)	(641)	(568)
Consumer Portfolio Segment [Member] | Business Activities Loans [Member]
Loans receivable, gross	67,635	85,934
Allowance for loan and lease losses	(295)	(341)
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Loans receivable, gross		85,934
Construction Portfolio Segment [Member]
Allowance for loan and lease losses	(739)	(477)	(350)	(481)
Construction Portfolio Segment [Member] | Business Activities Loans [Member]
Loans receivable, gross	66,984	48,388
Allowance for loan and lease losses	(739)	(477)
Construction Portfolio Segment [Member] | Acquired Loans [Member]
Loans receivable, gross		48,388
Construction to Permanent Portfolio Segment [Member]
Allowance for loan and lease losses	(162)	(130)	$ (108)	$ (54)
Construction to Permanent Portfolio Segment [Member] | Business Activities Loans [Member]
Loans receivable, gross	15,035	14,064
Allowance for loan and lease losses	$ (162)	(130)
Construction to Permanent Portfolio Segment [Member] | Acquired Loans [Member]
Loans receivable, gross		$ 14,064