Revenue By Market (Schedule Of Net Revenue By Market)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Major Customer [Line Items]
Total Revenue	$ 88,310	$ 68,009	$ 68,527
Medical [Member]
Revenue, Major Customer [Line Items]
Total Revenue	52,336	37,602	39,609
Hearing Health [Member]
Revenue, Major Customer [Line Items]
Total Revenue	23,316	21,882	21,089
Hearing Health - Direct To Customer [Member]
Revenue, Major Customer [Line Items]
Total Revenue	6,492	1,025
Professional Audio Communications [Member]
Revenue, Major Customer [Line Items]
Total Revenue	$ 6,166	$ 7,500	$ 7,829