Fair Value Measurement - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Apache Design Solutions, Inc.	Aug. 01, 2011 Apache Design Solutions, Inc.
Fair Value Measurements [Line Items]
Short-term investment time deposits maturity minimum, in months	3 months	3 months
Short-term investment time deposits maturity maximum, in years	1 year	1 year
Unrealized gains or losses associated with deposits	$ 0	$ 0
Contingent consideration arrangement, additional payments					12,000,000
Contingent consideration				9,700,000
Deferred compensation	$ 2,091,000	$ 2,091,000	$ 2,073,000