Other Assets, Net (Narrative) (Details) € in Thousands, $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2019 EUR (€)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 31, 2019 USD ($)
Other Assets, Net [Line Items]
Accumulated amortization		$ 28,213	$ 27,522
Period of future quarterly installments of non-cash amounts, software capitalization		4 years
Cash Paid At Closing [Member]
Other Assets, Net [Line Items]
Software, capitalized cost				$ 586
Software, Future Quarterly Installments Next Four Years [Member]
Other Assets, Net [Line Items]
Software, capitalized cost				869
Due In January 2023 [Member]
Other Assets, Net [Line Items]
Software, capitalized cost				533
Software, Value Of Partnership And License Agreement Transferred [Member]
Other Assets, Net [Line Items]
Software, capitalized cost				$ 1,691
Self-Fitting Software [Member]
Other Assets, Net [Line Items]
Accumulated amortization		$ 982	$ 884
Self-Fitting Software [Member] | Maximum [Member]
Other Assets, Net [Line Items]
Estimated useful life		7 years
Self-Fitting Software [Member] | Minimum [Member]
Other Assets, Net [Line Items]
Estimated useful life		5 years
Other Accrued Current Liabilities [Member]
Other Assets, Net [Line Items]
Software Purchase, Outstanding Liabilities		$ 238
Other Long Term Liabilities [Member]
Other Assets, Net [Line Items]
Software Purchase, Outstanding Liabilities		$ 857
Soundperience [Member]
Other Assets, Net [Line Items]
Payments for Software | €	€ 1,750
Percent Of Ownership Interest Transferred	49.00%