Intangible Assets (Schedule Of Amortization Expense For Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 36	$ 44	$ 81	$ 86
Patents
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	28	26	56	51
Software
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	7	8	15	16
Marketing assets and customer relationships
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	1	3	5	6
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 0	$ 7	$ 5	$ 13