Note 6 - Loans Receivable, Net and Allowance for Loan Losses - Loan Portfolio Summarized by Past Due Status (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Loans, past due	$ 8,308	$ 4,802
Loans, current	342,559	244,965
Loans	350,867	249,767
Loans > 90 days and accruing	892	190
The 30 to 89 Days Delinquent [Member]
Loans, past due	7,226	4,440
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due	1,082	362
Real Estate Portfolio Segment [Member]
Loans	209,651	204,000
Real Estate Portfolio Segment [Member] | One-to-four Family Residential Owner Occupied Loans [Member]
Loans, past due	1,307	1,371
Loans, current	4,078	4,927
Loans	5,385	6,298
Loans > 90 days and accruing
Real Estate Portfolio Segment [Member] | One-to-four Family Residential Owner Occupied Loans [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due	1,136	1,199
Real Estate Portfolio Segment [Member] | One-to-four Family Residential Owner Occupied Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due	171	172
Real Estate Portfolio Segment [Member] | One-to-four Family Residential Non-owner Occupied Loans [Member]
Loans, past due	175	1,069
Loans, current	40,697	38,828
Loans	40,872	39,897
Loans > 90 days and accruing
Real Estate Portfolio Segment [Member] | One-to-four Family Residential Non-owner Occupied Loans [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due	156	1,069
Real Estate Portfolio Segment [Member] | One-to-four Family Residential Non-owner Occupied Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due	19
Real Estate Portfolio Segment [Member] | Multi-family (Five Or More) Residential Loans [Member]
Loans, past due	1,723
Loans, current	21,091	22,233
Loans	22,814	22,233
Loans > 90 days and accruing
Real Estate Portfolio Segment [Member] | Multi-family (Five Or More) Residential Loans [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due	1,723
Real Estate Portfolio Segment [Member] | Multi-family (Five Or More) Residential Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due
Real Estate Portfolio Segment [Member] | Commercial Real Estate Loans [Member]
Loans, past due	4,862	1,176
Loans, current	124,103	118,147
Loans	128,965	119,323
Loans > 90 days and accruing	892	190
Real Estate Portfolio Segment [Member] | Commercial Real Estate Loans [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due	3,970	986
Real Estate Portfolio Segment [Member] | Commercial Real Estate Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due	892	190
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans, past due		1,120
Loans, current	7,512	11,403
Loans	7,512	12,523
Loans > 90 days and accruing
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due		1,120
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due
Real Estate Portfolio Segment [Member] | Home Equity Loan [Member]
Loans, past due	96
Loans, current	4,007	3,726
Loans	4,103	3,726
Loans > 90 days and accruing
Real Estate Portfolio Segment [Member] | Home Equity Loan [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due	96
Real Estate Portfolio Segment [Member] | Home Equity Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due
Commercial Portfolio Segment [Member]
Loans, past due	145	66
Loans, current	141,061	45,679
Loans	141,206	45,745
Loans > 90 days and accruing
Commercial Portfolio Segment [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due	145	66
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due
Consumer Portfolio Segment [Member]
Loans, past due
Loans, current	10	22
Loans	10	22
Loans > 90 days and accruing
Consumer Portfolio Segment [Member] | The 30 to 89 Days Delinquent [Member]
Loans, past due
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, past due