Note 5 - Investment Securities Available for Sale - Amortized Cost and Fair Value of Investment Securities Available for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Amortized cost	$ 10,840	$ 7,599
Gross unrealized gains	112	25
Gross unrealized losses	(2)	(1)
Fair value	10,950	7,623
Investment securities available for sale	10,950	7,623
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	5,333	6,099
Gross unrealized gains	30	15
Gross unrealized losses		(1)
Fair value	5,363	6,113
Investment securities available for sale	5,363	6,113
Corporate Debt Securities [Member]
Amortized cost	5,507	1,500
Gross unrealized gains	82	10
Gross unrealized losses	(2)
Fair value	5,587	1,510
Investment securities available for sale	5,587	1,510
Government National Mortgage Association (GNMA) Insured Loans [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	5,137	5,841
Gross unrealized gains	26	13
Gross unrealized losses		(1)
Fair value	5,163	5,853
Investment securities available for sale	5,163	5,853
Federal National Mortgage Association (FNMA) Insured Loans [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	196	258
Gross unrealized gains	4	2
Gross unrealized losses
Fair value	200	260
Investment securities available for sale	$ 200	$ 260

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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