Segment Reporting (Summary Of Data By Industry Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenue, net	$ 113,493	$ 113,948	$ 86,954
Impairment loss (Note 5 and 6)	3,765
Income (loss) from continuing operations before income taxes, non-controlling interest and discontinued operations	(1,863)	7,246	2,462
Depreciation and amortization	3,277	2,891	2,134
Capital expenditures	4,593	5,503	2,266
Intangible assets		2,585
Goodwill	9,551	10,808
Body Worn Devices [Member]
Segment Reporting Information [Line Items]
Revenue, net	107,373	107,090	80,462
Income (loss) from continuing operations before income taxes, non-controlling interest and discontinued operations	6,417	10,792	3,653
Depreciation and amortization	3,080	2,678	1,922
Capital expenditures	4,457	5,338	2,111
Identifiable assets (excluding goodwill)	101,311	97,725
Goodwill	9,551	9,551
Hearing Health DTEC [Member]
Segment Reporting Information [Line Items]
Revenue, net	6,120	6,858	6,492
Impairment loss (Note 5 and 6)	3,765
Income (loss) from continuing operations before income taxes, non-controlling interest and discontinued operations	(8,280)	(3,546)	(1,191)
Depreciation and amortization	197	213	212
Capital expenditures	136	165	$ 155
Identifiable assets (excluding goodwill)	$ 2,651	2,554
Intangible assets		2,585
Goodwill		$ 1,257