Note 3 - Available-for-sale Securities - Securities in a Continuous Loss Position (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Available-for-sale securities, less than 12 months, fair value	$ 639,465	$ 14,878,691
Available-for-sale securities, less than 12 months, gross unrealized losses	(1,391)	(179,074)
Available-for-sale securities, 12 months or more, fair value	715,953	7,302,788
Available-for-sale securities, 12 months or more, gross unrealized losses	(1,819)	(80,403)
Available-for-sale securities, fair value	1,355,418	22,181,479
Available-for-sale securities, gross unrealized losses	(3,210)	(259,477)
Asset-backed Securities [Member]
Available-for-sale securities, less than 12 months, fair value	639,465	10,201,840
Available-for-sale securities, less than 12 months, gross unrealized losses	(1,391)	(64,195)
Available-for-sale securities, 12 months or more, fair value		6,459,069
Available-for-sale securities, 12 months or more, gross unrealized losses		(55,579)
Available-for-sale securities, fair value	639,465	16,660,909
Available-for-sale securities, gross unrealized losses	(1,391)	(119,774)
US Government Agencies Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value
Available-for-sale securities, less than 12 months, gross unrealized losses
Available-for-sale securities, 12 months or more, fair value	715,953	843,719
Available-for-sale securities, 12 months or more, gross unrealized losses	(1,819)	(24,824)
Available-for-sale securities, fair value	715,953	843,719
Available-for-sale securities, gross unrealized losses	$ (1,819)	(24,824)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value		4,676,851
Available-for-sale securities, less than 12 months, gross unrealized losses		(114,879)
Available-for-sale securities, 12 months or more, fair value
Available-for-sale securities, 12 months or more, gross unrealized losses
Available-for-sale securities, fair value		4,676,851
Available-for-sale securities, gross unrealized losses		$ (114,879)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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