Goodwill And Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Apr. 02, 2011	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 37,883		$ 37,883
Accumulated Amortization	(25,986)		(25,216)
Net Amount	11,897		12,667
Amortization expense	770	835
Current Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	12,718		12,718
Accumulated Amortization	(11,507)		(11,403)
Net Amount	1,211		1,315
Patent And Patent Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	23,392		23,392
Accumulated Amortization	(12,732)		(12,079)
Net Amount	10,660		11,313
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	1,773		1,773
Accumulated Amortization	(1,747)		(1,734)
Net Amount	$ 26		$ 39