Note 6 - Fair Value - Reconciliation of Level 3 Assets (Details) - USD ($)		12 Months Ended
		Dec. 31, 2024		Dec. 31, 2023
Unrealized appreciation (depreciation)		$ (9,611,866)		$ (22,907,714)
Fair Value, Inputs, Level 3 [Member]
Fair value, balance		4,797,872		35,929,006
Purchases		2,441		140,000
Sales		(6,272,666)		(498,422)
Realized gains (losses)		(11,686,668)		(7,864,998)
Unrealized appreciation (depreciation)		9,611,866		(22,907,714)	[1]
Transfers		3,862,405		0
Fair value, balance		315,250		4,797,872
Common Stock [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		299,987		349,287
Purchases		0		0
Sales		0		(7,966)
Realized gains (losses)		0		(161,079)
Unrealized appreciation (depreciation)		(3,901,895)	[2]	119,745	[1]
Transfers		3,862,405		0
Fair value, balance		260,497		299,987
Common Stock [Member] | Advanced Materials Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		299,932		337,500
Purchases		0		0
Sales		0		0
Realized gains (losses)		0		0
Unrealized appreciation (depreciation)		(39,435)	[2]	(37,568)	[1]
Transfers		0		0
Fair value, balance		260,497		299,932
Common Stock [Member] | Equipment Leasing Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		55		11,130
Purchases		0		0
Sales		0		0
Realized gains (losses)		0		0
Unrealized appreciation (depreciation)		(55)	[2]	(11,075)	[1]
Transfers		0		0
Fair value, balance		0		55
Common Stock [Member] | Automotive Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		546
Purchases				0
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			(546)
Transfers				0
Fair value, balance				0
Common Stock [Member] | Semiconductor Equipment Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0
Purchases		0
Sales		0
Realized gains (losses)		0
Unrealized appreciation (depreciation)	[2]	(3,862,405)
Transfers		3,862,405
Fair value, balance		0		0
Common Stock [Member] | Intellectual Property Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		111
Purchases				0
Sales				(7,966)
Realized gains (losses)				(161,079)
Unrealized appreciation (depreciation)	[1]			168,934
Transfers				0
Fair value, balance				0
Preferred Stock [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		110,172		3,036,652
Purchases		2,441		0
Sales		(176,405)		(490,456)
Realized gains (losses)		(11,083,138)		(7,697,241)
Unrealized appreciation (depreciation)		11,176,396	[2]	5,261,217	[1]
Transfers		0		0
Fair value, balance		29,466		110,172
Preferred Stock [Member] | Equipment Leasing Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		110,172		865,995
Purchases		0		0
Sales		(20,000)		0
Realized gains (losses)		0		0
Unrealized appreciation (depreciation)		(60,706)	[2]	(755,823)	[1]
Transfers		0		0
Fair value, balance		29,466		110,172
Preferred Stock [Member] | Automotive Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		1,049,478
Purchases				0
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			(1,049,478)
Transfers				0
Fair value, balance				0
Preferred Stock [Member] | Intellectual Property Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		737,112
Purchases				0
Sales				(490,456)
Realized gains (losses)				(7,697,241)
Unrealized appreciation (depreciation)	[1]			7,450,585
Transfers				0
Fair value, balance				0
Preferred Stock [Member] | Aerospace Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		384,067
Purchases		2,441		0
Sales		(156,405)		0
Realized gains (losses)		(11,083,138)		0
Unrealized appreciation (depreciation)		11,237,102	[2]	(384,067)	[1]
Transfers		0		0
Fair value, balance		0		0
Debt [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		4,387,713
Purchases		0
Sales		(6,096,261)
Realized gains (losses)		(603,530)
Unrealized appreciation (depreciation)	[2]	2,337,365
Transfers		0
Fair value, balance		25,287		4,387,713
Debt [Member] | Advanced Materials Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		100,000
Purchases		0
Sales		(100,000)
Realized gains (losses)		0
Unrealized appreciation (depreciation)	[2]	0
Transfers		0
Fair value, balance		0		100,000
Debt [Member] | Automotive Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0
Purchases		0
Sales		(40,000)
Realized gains (losses)		0
Unrealized appreciation (depreciation)	[2]	40,000
Transfers		0
Fair value, balance		0		0
Debt [Member] | Aerospace Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		4,200,000
Purchases		0
Sales		(5,956,261)
Realized gains (losses)		(603,530)
Unrealized appreciation (depreciation)	[2]	2,359,791
Transfers		0
Fair value, balance		0		4,200,000
Debt [Member] | Medical Devices Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		87,713
Purchases		0
Sales		0
Realized gains (losses)		0
Unrealized appreciation (depreciation)	[2]	(62,426)
Transfers		0
Fair value, balance		25,287		87,713
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		957,125
Purchases				0
Sales				0
Realized gains (losses)				(6,678)
Unrealized appreciation (depreciation)	[1]			(950,447)
Transfers				0
Fair value, balance				0
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Contract [Member]
Fair value, balance		0		957,125
Purchases				0
Sales				0
Realized gains (losses)				(6,678)
Unrealized appreciation (depreciation)	[1]			(950,447)
Transfers				0
Fair value, balance				0
Convertible Debt [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		4,387,713		31,585,942
Purchases				140,000
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			(27,338,229)
Transfers				0
Fair value, balance				4,387,713
Convertible Debt [Member] | Advanced Materials Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		100,000		100,000
Purchases				0
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			0
Transfers				0
Fair value, balance				100,000
Convertible Debt [Member] | Automotive Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		0		7,809,430
Purchases				140,000
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			(7,949,430)
Transfers				0
Fair value, balance				0
Convertible Debt [Member] | Aerospace Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		4,200,000		6,559,791
Purchases				0
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			(2,359,791)
Transfers				0
Fair value, balance				4,200,000
Convertible Debt [Member] | Medical Devices Sector [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value, balance		$ 87,713		17,116,721
Purchases				0
Sales				0
Realized gains (losses)				0
Unrealized appreciation (depreciation)	[1]			(17,029,008)
Transfers				0
Fair value, balance				$ 87,713

[1] The net change in unrealized appreciation (depreciation) from Level 3 instruments held as of December 31, 2023 was $(30,530,677).

[2] The net change in unrealized appreciation (depreciation) from Level 3 instruments held as of December 31, 2024 was $(4,025,027).