Revenue By Market (Schedule Of Net Revenue By Market) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue, Major Customer [Line Items]
Total Net Revenue	$ 116,462	$ 90,637	$ 68,980
Body Worn Devices Segment [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	109,604	84,145
Hearing Health Direct-to-End Consumer [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	6,858	6,492
Medical Biotelemetry [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	75,645	53,452	36,618
Hearing Health [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	26,720	24,527	23,837
Hearing Health Direct-to-End Consumer [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	6,858	6,492	1,025
Professional Audio Communications [Member]
Revenue, Major Customer [Line Items]
Total Net Revenue	$ 7,239	$ 6,166	$ 7,500