Note 11 - Fair Value Measurements and Fair Values of Financial Instruments - Financial Assets and Liabilities on a Recurring and Nonrecurring (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Investment securities available for sale	$ 10,950	$ 7,623
Fair Value, Recurring [Member]
Investment securities available for sale	10,950	7,623
Total fair value measurements	10,950	7,623
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale
Total fair value measurements
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale	10,950	7,623
Total fair value measurements	10,950	7,623
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale
Total fair value measurements
Fair Value, Nonrecurring [Member]
Total fair value measurements	710	2,143
Impaired loans	321	319
Other Real Estate Owned	389	1,824
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Total fair value measurements
Impaired loans
Other Real Estate Owned
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Total fair value measurements
Impaired loans
Other Real Estate Owned
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Total fair value measurements	710	2,143
Impaired loans	321	319
Other Real Estate Owned	389	1,824
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Investment securities available for sale	5,363	6,113
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Government National Mortgage Association (GNMA) Insured Loans [Member]
Investment securities available for sale	5,163	5,853
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Government National Mortgage Association (GNMA) Insured Loans [Member] | Fair Value, Recurring [Member]
Investment securities available for sale	5,163	5,853
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Government National Mortgage Association (GNMA) Insured Loans [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Government National Mortgage Association (GNMA) Insured Loans [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale	5,163	5,853
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Government National Mortgage Association (GNMA) Insured Loans [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Federal National Mortgage Association (FNMA) Insured Loans [Member]
Investment securities available for sale	200	260
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Federal National Mortgage Association (FNMA) Insured Loans [Member] | Fair Value, Recurring [Member]
Investment securities available for sale	200	260
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Federal National Mortgage Association (FNMA) Insured Loans [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Federal National Mortgage Association (FNMA) Insured Loans [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale	200	260
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Federal National Mortgage Association (FNMA) Insured Loans [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale
Corporate Debt Securities [Member]
Investment securities available for sale	5,587	1,510
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Investment securities available for sale	5,587	1,510
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale	5,587	1,510
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale