Income Taxes (Components Of Net Deferred Income Tax Assets And Net Deferred Income Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Intangibles	$ 24,232	$ 40,014
Stock options and restricted stock awards	5,988	14,384
Reserves and allowances	11,308	20,022
Net operating loss carryforwards	35,004	29,398
Tax credit carryforwards	10,908	13,571
Accrued liabilities	3,011	5,330
Deferred revenue	4,629	3,502
Valuation allowance	(80,796)	(109,913)
Total deferred income tax assets	14,284	16,308
Intangibles	11,301	16,968
Property, plant and equipment	7,304	8,818
Other	642
Total deferred income tax liabilities	19,247	25,786
Net deferred income tax liabilities	$ (4,963)	$ (9,478)