Fair Value Measurement (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Apache Design Solutions, Inc. [Member]	Aug. 01, 2011 Apache Design Solutions, Inc. [Member]
Fair Value Measurement [Line Items]
Unrealized gains or losses associated with deposits	$ 0	$ 0
Short-term investment time deposits maturity minimum, in months	3
Short-term investment time deposits maturity maximum, in years	1
Transfer amounts in or out of Level 1 or Level 2 fair value measurements	0
Contingent consideration arrangement, additional payments				12,000,000
Deferred compensation	2,073,000
Contingent consideration			$ 9,600,000	$ (9,501,000)