Note L - Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
REVENUES	$ 403	$ 370	$ 844	$ 787
Interest income, net	275	9	473	5
Investment income (loss)	43	(2,373)	388	(2,328)
Manufacturing cost of sales	(208)	(227)	(400)	(469)
Engineering, selling and administrative	(633)	(623)	(1,191)	(1,645)
Other expense, net	(12)	1	(24)	2
INCOME (LOSS) FROM OPERATIONS	(132)	(2,843)	90	(3,648)
Operating Segments [Member] | Electronic Instruments [Member]
REVENUES	403	370	844	787
Interest income, net	0	0	0	0
Investment income (loss)	0	0	0	0
Manufacturing cost of sales	(208)	(227)	(400)	(469)
Engineering, selling and administrative	(173)	(165)	(350)	(332)
Other expense, net	0	0	0	0
INCOME (LOSS) FROM OPERATIONS	22	(22)	94	(14)
Operating Segments [Member] | Merchant Investment [Member]
REVENUES	0	0	0	0
Interest income, net	255	0	255	0
Investment income (loss)	0	0	0	0
Manufacturing cost of sales	0	0	0	0
Engineering, selling and administrative	(88)	0	(88)	0
Other expense, net	0	0	0	0
INCOME (LOSS) FROM OPERATIONS	167	0	167	0
Corporate, Non-Segment [Member]
REVENUES	0	0	0	0
Interest income, net	20	9	218	5
Investment income (loss)	43	(2,373)	388	(2,328)
Manufacturing cost of sales	0	0	0	0
Engineering, selling and administrative	(372)	(458)	(753)	(1,313)
Other expense, net	(12)	1	(24)	2
INCOME (LOSS) FROM OPERATIONS	$ (321)	$ (2,821)	$ (171)	$ (3,634)