Note 3 - Segment Information - Schedule of Other Segment Disclosures (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Interest revenue (a)	[1]	$ 442	$ 531	$ 1,287	$ 1,568
Amortization (b)	[2]	(27)	(11)	(16)	0
Stock-based compensation (c)	[3]	(18)	(9)	(44)	(27)
Capital expenditures		0	0	0	0
Corporate Segment [Member]
Interest revenue (a)	[1]	168	213	504	646
Amortization (b)	[2]	0	0	0	0
Stock-based compensation (c)	[3]	(18)	(9)	(44)	(27)
Capital expenditures		0	0	0	0
Operating Segments [Member]
Interest revenue (a)	[1]	442	531	1,287	1,568
Amortization (b)	[2]	(27)	(11)	(16)	0
Stock-based compensation (c)	[3]	(18)	(9)	(44)	(27)
Capital expenditures		0	0	0	0
Operating Segments [Member] | Electronic Instruments [Member]
Interest revenue (a)	[1]	0	0	0	0
Amortization (b)	[2]	(27)	(11)	(16)	0
Stock-based compensation (c)	[3]	0	0	0	0
Capital expenditures		0	0	0	0
Operating Segments [Member] | Merchant Investment [Member]
Interest revenue (a)	[1]	274	318	783	922
Amortization (b)	[2]	0	0	0	0
Stock-based compensation (c)	[3]	0	0	0	0
Capital expenditures		0	0	0	0
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member]
Interest revenue (a)	[1]	0	0	0	0
Amortization (b)	[2]	0	0	0	0
Stock-based compensation (c)	[3]	0	0	0	0
Capital expenditures		$ 0	$ 0	$ 0	$ 0

[1] Interest revenue is included in Net investment income on the Consolidated Statements of Operations.

[2] Depreciation and Amortization are included within the other segment expense captions, such as Manufacturing cost of sales, Engineering, or Other segment items.

[3] Stock-based compensation is included within the Compensation expense caption.