Intangible Assets (Summary Of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 13,125	$ 6,429
Accumulated Amortization	(2,340)	(884)
Net Carrying Amount	10,785	5,545	$ 4,844
Customer List [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,400
Accumulated Amortization	(467)
Net Carrying Amount	5,933
Self-Fitting Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,975	3,679
Accumulated Amortization	(596)
Net Carrying Amount	3,379	3,679
Technology Access [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,750	2,750
Accumulated Amortization	(1,277)	(884)
Net Carrying Amount	$ 1,473	$ 1,866