Revenue By Market (Schedule Of Net Revenue By Market) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue, Major Customer [Line Items]
Total Net Revenue	$ 30,109	$ 25,363
Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	9,316	9,430
Products and Services Transferred over Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	20,793	15,933
Medical Biotelemetry, Diabetes [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	17,164	13,562
Medical Biotelemetry, Diabetes [Member] | Products and Services Transferred over Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	17,164	13,562
Medical Biotelemetry, Other Medical [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	3,629	2,371
Medical Biotelemetry, Other Medical [Member] | Products and Services Transferred over Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	3,629	2,371
Hearing Health Value Based DTEC [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	1,630	1,791
Hearing Health Value Based DTEC [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	1,630	1,791
Hearing Health Value Based ITEC [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	2,577	2,629
Hearing Health Value Based ITEC [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	2,577	2,629
Legacy OEM [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	3,342	3,181
Legacy OEM [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	3,342	3,181
Professional Audio Communications [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	1,767	1,829
Professional Audio Communications [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	$ 1,767	$ 1,829