Note 5 - Supplemental Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	December 31,
	2020		2019
Cash	$	10,562	$	7,135
Restricted cash		91		270
Total	$	10,653	$	7,405

Schedule of Inventory, Current [Table Text Block]

	December 31,
	2020		2019
Raw materials	$	17,277	$	18,485
Work in process		3,411		2,548
Finished products		7,505		8,726
Total	$	28,193	$	29,759

Property, Plant and Equipment [Table Text Block]

	December 31,
	2020			2019
Land	$	1,273		$	1,273
Buildings and leasehold improvements		15,393			15,386
Machinery and equipment		61,048			55,058
Furniture and fixtures		2,235			2,194
Computer hardware and software		6,894			6,712
Construction in progress		1,227			4,730
		88,070			85,353
Less – Accumulated depreciation		(65,220	)		(62,828	)
Total	$	22,850		$	22,525

Schedule of Goodwill [Table Text Block]

	Battery & Energy Products		Communications Systems		Total
Balance – January 1, 2019	$	8,616	$	11,493	$	20,109
Acquisition of SWE		6,534		-		6,534
Effect of foreign currency translation		110		-		110
Balance – December 31, 2019		15,260		11,493		26,753
Effect of foreign currency translation		265		-		265
Balance – December 31, 2020	$	15,525	$	11,493	$	27,018

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

	December 31, 2020,
	Cost		Accumulated amortization		Net
Trademarks	$	3,410	$	-	$	3,410
Customer relationships		9,171		5,115		4,056
Patents and technology		5,557		5,014		543
Distributor relationships		377		377		0
Trade name		1,524		324		1,200
Total other intangible assets	$	20,039	$	10,830	$	9,209

	December 31, 2019,
	Cost		Accumulated amortization		Net
Trademarks	$	3,403	$	-	$	3,403
Customer relationships		9,080		4,721		4,359
Patents and technology		5,521		4,869		652
Distributor relationships		377		377		-
Trade name		1,511		204		1,307
Total other intangible assets	$	19,892	$	10,171	$	9,721

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

	Year ended December 31,
	2020		2019
Research and development expense	$	124	$	130
Selling, general and administrative expense		471		395
Total	$	595	$	525