Note 10 - Business Segment Information - Revenue by Business Segment Sector (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Revenues	$ 47,943	$ 48,561	$ 95,388	$ 99,307
UNITED STATES
Revenues	$ 28,654	$ 35,364	$ 59,905	$ 74,833
Revenue, percentage	60.00%	73.00%	63.00%	75.00%
Non-US [Member]
Revenues	$ 19,289	$ 13,197	$ 35,483	$ 24,474
Revenue, percentage	40.00%	27.00%	37.00%	25.00%
Commercial [Member]
Revenues	$ 29,860	$ 31,333	$ 60,361	$ 63,620
Revenue, percentage	62.00%	65.00%	63.00%	64.00%
Government & Defense [Member]
Revenues	$ 18,083	$ 17,228	$ 35,027	$ 35,687
Revenue, percentage	38.00%	35.00%	37.00%	36.00%
Battery & Energy Products Segment [Member]
Revenues	$ 44,189	$ 45,867	$ 88,344	$ 92,188
Battery & Energy Products Segment [Member] \| UNITED STATES
Revenues	26,057	33,300	55,001	68,482
Battery & Energy Products Segment [Member] \| Non-US [Member]
Revenues	18,132	12,567	33,343	23,706
Battery & Energy Products Segment [Member] \| Commercial [Member]
Revenues	29,860	31,333	60,361	63,620
Battery & Energy Products Segment [Member] \| Government & Defense [Member]
Revenues	14,329	14,534	27,983	28,568
Communications Systems Segment [Member]
Revenues	3,754	2,694	7,044	7,119
Communications Systems Segment [Member] \| UNITED STATES
Revenues	2,597	2,064	4,904	6,351
Communications Systems Segment [Member] \| Non-US [Member]
Revenues	1,157	630	2,140	768
Communications Systems Segment [Member] \| Commercial [Member]
Revenues	0	0	0	0
Communications Systems Segment [Member] \| Government & Defense [Member]
Revenues	$ 3,754	$ 2,694	$ 7,044	$ 7,119

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-40

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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+ Details