Note 5 - Supplemental Balance Sheet Information (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	September 30,		December 31,
	2020		2019
Cash	$	13,690	$	7,135
Restricted cash		87		270
Total	$	13,777	$	7,405

Schedule of Inventory, Current [Table Text Block]

	September 30,		December 31,
	2020		2019
Raw materials	$	17,600	$	18,485
Work in process		3,861		2,548
Finished goods		8,285		8,726
Total	$	29,746	$	29,759

Property, Plant and Equipment [Table Text Block]

	September 30,			December 31,
	2020			2019
Land	$	1,273		$	1,273
Buildings and leasehold improvements		15,365			15,386
Machinery and equipment		55,869			55,058
Furniture and fixtures		2,219			2,194
Computer hardware and software		6,812			6,712
Construction in process		5,622			4,730
		87,160			85,353
Less: Accumulated depreciation		(64,555	)		(62,828	)
Property, plant and equipment, net	$	22,605		$	22,525

	Three-month period ended				Nine-month period ended
	September 30,		September 29,		September 30,		September 29,
	2020		2019		2020		2019
Depreciation expense	$	582	$	586	$	1,743	$	1,548

Schedule of Goodwill [Table Text Block]

	Battery & Energy			Communications
	Products			Systems		Total
Balance – December 31, 2019		15,260			11,493		26,753
Effect of foreign currency translation		(48	)		-		(48	)
Balance – September 30, 2020	$	15,212		$	11,493	$	26,705

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

	September 30, 2020
			Accumulated
	Cost		Amortization		Net
Trademarks	$	3,406	$	-	$	3,406
Customer relationships		9,020		4,975		4,045
Patents and technology		5,496		4,952		544
Distributor relationships		377		377		-
Trade name		1,501		284		1,217
Total	$	19,800	$	10,588	$	9,212

	December 31, 2019
			Accumulated
	Cost		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	$	19,892	$	10,171	$	9,721

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

	Three-month period ended				Nine-month period ended
	September 30,		September 29,		September 30,		September 29,
	2020		2019		2020		2019
Amortization included in:
Research and development	$	31	$	32	$	92	$	98
Selling, general and administrative		118		116		352		274
Total amortization expense	$	149	$	148	$	444	$	372