Note 3 - Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2026		Sep. 30, 2025		Sep. 30, 2026		Sep. 30, 2025
Net sales		$ 720		$ 661		$ 2,152		$ 1,650
Net investment income		744		442		1,545		1,287
Net gains		0		5		5		13
Total revenues		1,464		1,108		3,702		2,950
Manufacturing cost of sales		491		312		1,206		760
Engineering		91		74		258		188
Commissions		3		12		46		52
Sales and marketing		55		47		177		139
Accounting		65		49		234		174
Compensation		324		132		1,588		589
Corporate allocations		0	[1]	0	[1]	0	[1]	0	[2]
Other segment items	[3]	410		362		1,400		918
Engineering, selling and administrative		948		676		3,703		2,060
Total expenses		1,439		988		4,909		2,820
Segment (loss) profit		25		120		(1,207)		130
Income before income taxes		25		120		(1,207)		130
Net gains (losses)		0		5		5		13
Net gains		0		5		5		13
Income before income taxes		25		120		(1,207)		130
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Net sales		0		0		0		0
Net investment income		453		168		792		504
Net gains		0		5		5		13
Total revenues		453		173		797		517
Manufacturing cost of sales		0		0		0		0
Engineering		0		0		0		0
Commissions		0		0		0		0
Sales and marketing		0		0		0		0
Accounting		65		49		234		174
Compensation		265		74		1,415		423
Corporate allocations		(180)	[1]	(158)	[1]	(501)	[1]	(366)	[2]
Other segment items	[3]	336		321		1,094		777
Engineering, selling and administrative		486		286		2,242		1,008
Total expenses		486		286		2,242		1,008
Segment (loss) profit		(33)		(113)		(1,445)		(491)
Net gains (losses)		0		5		5		13
Net gains		0		5		5		13
Electronic Instruments [Member] | Operating Segments [Member]
Net sales		720		661		2,152		1,650
Net investment income		0		0		0		0
Net gains		0		0		0		0
Total revenues		720		661		2,152		1,650
Manufacturing cost of sales		491		312		1,206		760
Engineering		91		74		258		188
Commissions		3		12		46		52
Sales and marketing		55		47		177		139
Accounting		0		0		0		0
Compensation		59		58		173		166
Corporate allocations		12	[1]	13	[1]	40	[1]	35	[2]
Other segment items	[3]	73		41		271		119
Engineering, selling and administrative		293		245		965		699
Total expenses		784		557		2,171		1,459
Segment (loss) profit		(64)		104		(19)		191
Net gains (losses)		0		0		0		0
Net gains		0		0		0		0
Merchant Investment [Member] | Operating Segments [Member]
Net sales		0		0		0		0
Net investment income		291		274		753		783
Net gains		0		0		0		0
Total revenues		291		274		753		783
Manufacturing cost of sales		0		0		0		0
Engineering		0		0		0		0
Commissions		0		0		0		0
Sales and marketing		0		0		0		0
Accounting		0		0		0		0
Compensation		0		0		0		0
Corporate allocations		168	[1]	145	[1]	461	[1]	331	[2]
Other segment items	[3]	1		0		35		22
Engineering, selling and administrative		169		145		496		353
Total expenses		169		145		496		353
Segment (loss) profit		122		129		257		430
Net gains (losses)		0		0		0		0
Net gains		$ 0		$ 0		$ 0		$ 0

[1] The Electronic Instruments and Merchant Investment segments are allocated overhead expenses from the Corporate segment based on each segment's assets as a percentage of Total assets.

[2] The Electronic Instruments and Merchant Investment segments are allocated overhead expenses from the Corporate segment based on each segment's asset as a percentage of Total assets.

[3] Other segment items for each reportable segment includes the following: Electronic Instruments - rent, amortization, professional service fees, and certain other overhead expenses. Merchant Investment - legal expense and certain other overhead expenses. Corporate - legal expense, insurance expense, filing fees, fees paid to M-tron Industries, Inc. under the Amended and Restated Transitional Administrative and Management Services Agreement, expense reimbursements paid to / received from M-tron Industries, Inc., and certain other overhead expenses.