Note 3 - Available-for-sale Securities - Securities in a Continuous Loss Position (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Available-for-sale securities, less than 12 months, fair value	$ 3,412,960	$ 14,878,691
Available-for-sale securities, less than 12 months, gross unrealized losses	(19,182)	(179,074)
Available-for-sale securities, 12 months or more, fair value	1,989,665	7,302,788
Available-for-sale securities, 12 months or more, gross unrealized losses	(24,556)	(80,403)
Available-for-sale securities, fair value	5,402,625	22,181,479
Available-for-sale securities, gross unrealized losses	(43,738)	(259,477)
Asset-backed Securities [Member]
Available-for-sale securities, less than 12 months, fair value	437,108	10,201,840
Available-for-sale securities, less than 12 months, gross unrealized losses	(2,756)	(64,195)
Available-for-sale securities, 12 months or more, fair value	1,242,786	6,459,069
Available-for-sale securities, 12 months or more, gross unrealized losses	(11,904)	(55,579)
Available-for-sale securities, fair value	1,679,894	16,660,909
Available-for-sale securities, gross unrealized losses	(14,660)	(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	746,879	843,719
Available-for-sale securities, 12 months or more, gross unrealized losses	(12,652)	(24,824)
Available-for-sale securities, fair value	746,879	843,719
Available-for-sale securities, gross unrealized losses	(12,652)	(24,824)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value	2,975,852	4,676,851
Available-for-sale securities, less than 12 months, gross unrealized losses	(16,426)	(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	2,975,852	4,676,851
Available-for-sale securities, gross unrealized losses	$ (16,426)	$ (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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