Note 4 - Loans Receivable and Related Allowance for Loan Losses - Loan Portfolio by Internal Risk Rating (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Loans	$ 811,891	$ 701,904
Residential Portfolio Segment [Member]
Loans	306,986	293,170
Home Equity Loans and Lines of Credit [Member]
Loans	93,652	97,541
Commercial Real Estate Portfolio Segment [Member]
Loans	264,909	229,951
Commercial Portfolio Segment [Member]
Loans	117,399	66,603
Consumer Portfolio Segment [Member]
Loans	28,945	14,639
Not Rated [Member]
Loans	427,480	403,487
Not Rated [Member] | Residential Portfolio Segment [Member]
Loans	305,446	291,843
Not Rated [Member] | Home Equity Loans and Lines of Credit [Member]
Loans	93,206	97,087
Not Rated [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans
Not Rated [Member] | Commercial Portfolio Segment [Member]
Loans
Not Rated [Member] | Consumer Portfolio Segment [Member]
Loans	28,828	14,557
Pass [Member]
Loans	362,238	281,380
Pass [Member] | Residential Portfolio Segment [Member]
Loans
Pass [Member] | Home Equity Loans and Lines of Credit [Member]
Loans
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	247,661	216,744
Pass [Member] | Commercial Portfolio Segment [Member]
Loans	114,577	64,636
Pass [Member] | Consumer Portfolio Segment [Member]
Loans
Special Mention [Member]
Loans	5,415	5,574
Special Mention [Member] | Residential Portfolio Segment [Member]
Loans
Special Mention [Member] | Home Equity Loans and Lines of Credit [Member]
Loans
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	5,198	5,370
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans	217	204
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans
Substandard [Member]
Loans	16,758	11,463
Substandard [Member] | Residential Portfolio Segment [Member]
Loans	1,540	1,327
Substandard [Member] | Home Equity Loans and Lines of Credit [Member]
Loans	446	454
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	12,050	7,837
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans	2,605	1,763
Substandard [Member] | Consumer Portfolio Segment [Member]
Loans	117	82
Doubtful [Member]
Loans
Doubtful [Member] | Residential Portfolio Segment [Member]
Loans
Doubtful [Member] | Home Equity Loans and Lines of Credit [Member]
Loans
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans
Doubtful [Member] | Commercial Portfolio Segment [Member]
Loans
Doubtful [Member] | Consumer Portfolio Segment [Member]
Loans