Note 11 - Business Segment Information - Domestic and International Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues	$ 33,234	$ 21,761	$ 95,733	$ 74,504
UNITED STATES
Revenues	$ 16,980	$ 9,190	$ 47,912	$ 37,014
Revenue, percentage	51.00%	42.00%	50.00%	50.00%
Non-US [Member]
Revenues	$ 16,254	$ 12,571	$ 47,821	$ 37,490
Revenue, percentage	49.00%	58.00%	50.00%	50.00%
Battery & Energy Products Segment [Member]
Revenues	$ 28,583	$ 20,008	$ 87,873	$ 64,994
Battery & Energy Products Segment [Member] \| UNITED STATES
Revenues	13,433	7,941	41,303	32,344
Battery & Energy Products Segment [Member] \| Non-US [Member]
Revenues	15,150	12,067	46,570	32,650
Communications Systems Segment [Member]
Revenues	4,651	1,753	7,860	9,510
Communications Systems Segment [Member] \| UNITED STATES
Revenues	3,547	1,249	6,609	4,670
Communications Systems Segment [Member] \| Non-US [Member]
Revenues	$ 1,104	$ 504	$ 1,251	$ 4,840

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
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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+ Details