Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Aug. 01, 2011	Aug. 01, 2012 Esterel Technologies, S.A.	Aug. 01, 2012 Esterel Technologies, S.A. Developed Software	Aug. 01, 2012 Esterel Technologies, S.A. Customer Relationships	Aug. 01, 2012 Esterel Technologies, S.A. Platform Trade Names	Aug. 01, 2011 Apache Design Solutions, Inc.	Aug. 01, 2011 Apache Design Solutions, Inc. Developed Software	Aug. 01, 2011 Apache Design Solutions, Inc. Customer Relationships	Aug. 01, 2011 Apache Design Solutions, Inc. Contract Backlog	Aug. 01, 2011 Apache Design Solutions, Inc. Platform Trade Names	Aug. 01, 2011 Apache Design Solutions, Inc. Apache Trade Name
Business Combination, Separately Recognized Transactions [Line Items]
Cash and short-term investments		$ 13,075				$ 31,948
Accounts receivable and other tangible assets		4,737				6,011
Amortizable intangible assets	153,800		10,717	21,421		156,100	82,500	36,100	13,500		2,100
Indefinite-lived intangible assets					2,695					21,900
Accounts payable and other liabilities		(4,936)				(16,867)
Deferred revenue		(1,139)				(10,100)
Net deferred tax liabilities	(46,100)	(9,286)				(47,229)
Total identifiable net assets		37,284				119,863
Goodwill		$ 20,866				$ 194,114