Note 4 - Supplemental Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	December 31,
	2021		2020
Cash	$	8,329	$	10,562
Restricted cash		84		91
Total	$	8,413	$	10,653

Schedule of Inventory, Current [Table Text Block]

	December 31,
	2021		2020
Raw materials	$	21,660	$	17,277
Work in process		4,227		3,411
Finished products		7,302		7,505
Total	$	33,189	$	28,193

Property, Plant and Equipment [Table Text Block]

	December 31,
	2021			2020
Land	$	1,273		$	1,273
Buildings and leasehold improvements		15,442			15,393
Machinery and equipment		63,780			61,048
Furniture and fixtures		2,588			2,235
Computer hardware and software		7,579			6,894
Construction in progress		761			1,227
		91,423			88,070
Less – Accumulated depreciation		(68,218	)		(65,220	)
Total	$	23,205		$	22,850

Schedule of Goodwill [Table Text Block]

	Battery & Energy Products		Communications Systems		Total
Balance – January 1, 2021	$	15,525	$	11,493	$	27,018
Acquisition of Excell		11,019		-		11,019
Effect of foreign currency translation		31		-		31
Balance – December 31, 2021	$	26,575	$	11,493	$	38,068

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	December 31, 2021,
	Cost		Accumulated amortization		Net
Customer relationships	$	13,214	$	5,484	$	7,730
Patents and technology		5,667		5,126		541
Trade names		4,670		436		4,234
Trademarks		3,413		-		3,413
Other		1,490		18		1,472
Total other intangible assets	$	28,454	$	11,064	$	17,390

	December 31, 2020,
	Cost		Accumulated amortization		Net
Customer relationships	$	9,171	$	5,115	$	4,056
Patents and technology		5,557		5,014		543
Trade name		1,524		324		1,200
Trademarks		3,410		-		3,410
Total other intangible assets	$	19,662	$	10,453	$	9,209

Finite-lived Intangible Assets Amortization Expense [Table Text Block]

	Year ended December 31,
	2021		2020
Research and development expense	$	118	$	124
Selling, general and administrative expense		515		471
Total	$	633	$	595