Revenue By Market (Schedule Of Net Revenue By Market) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Major Customer [Line Items]
Total Revenue	$ 30,134	$ 25,061	$ 85,657	$ 68,800
Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Revenue	10,778	9,593	30,170	137,601
Products and Services Transferred over Time [Member]
Revenue, Major Customer [Line Items]
Total Revenue	19,356	15,468	55,487	41,220
Body Worn Devices Segment [Member]
Revenue, Major Customer [Line Items]
Total Revenue	28,644	23,298	80,325	64,212
Hearing Health Direct-to-End Consumer [Member]
Revenue, Major Customer [Line Items]
Total Revenue	1,490	1,763	5,332	4,588
Medical Biotelemetry [Member] | Body Worn Devices Segment [Member]
Revenue, Major Customer [Line Items]
Total Revenue	19,356	15,468	55,487	41,220
Medical Biotelemetry [Member] | Body Worn Devices Segment [Member] | Products and Services Transferred over Time [Member]
Revenue, Major Customer [Line Items]
Total Revenue	19,356	15,468	55,487	41,220
Hearing Health Market [Member] | Body Worn Devices Segment [Member]
Revenue, Major Customer [Line Items]
Total Revenue	7,284	6,215	19,484	18,487
Hearing Health Market [Member] | Body Worn Devices Segment [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Revenue	7,284	6,215	19,484	18,487
Professional Audio Communications [Member] | Body Worn Devices Segment [Member]
Revenue, Major Customer [Line Items]
Total Revenue	2,004	1,615	5,353	4,505
Professional Audio Communications [Member] | Body Worn Devices Segment [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Revenue	2,004	1,615	5,353	4,505
Hearing Health Direct-to-End Consumer (DTEC) Market [Member] | Hearing Health Direct-to-End Consumer [Member]
Revenue, Major Customer [Line Items]
Total Revenue	1,490	1,763	5,333	4,588
Hearing Health Direct-to-End Consumer (DTEC) Market [Member] | Hearing Health Direct-to-End Consumer [Member] | Products and Services Transferred at Point in Time [Member]
Revenue, Major Customer [Line Items]
Total Revenue	$ 1,490	$ 1,763	$ 5,333	$ 4,588