Leases (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
San Jose Office
Operating Leased Assets [Line Items]
Future minimum lease payments	$ 7.5
Global Office Space
Operating Leased Assets [Line Items]
Lease rental expense incurred	15.8	14.1	13.7
Operating leases, future minimum payments due, next twelve months	13.7
Operating Leases, Future Minimum Payments, Due in Two Years	10.9
Future minimum lease payments, Year 3	9.0
Future minimum lease payments, Year 4	6.7
Future minimum lease payments, Year 5	6.4
Apache Design Inc [Member] | San Jose Office
Operating Leased Assets [Line Items]
Area of real estate property	52,000
Operating leases, future minimum payments due, next twelve months	0.9
Lease Agreement Effective September 14, 2012 | Canonsburg Office, New Company Headquarters
Operating Leased Assets [Line Items]
Area of real estate property	186,000
Lease rental expense incurred	0.8
Period of leased property	183 months
Base rent, years one through five	4.3
Base rent, years six through ten	4.5
Base rent, years eleven through fifteen	4.7
Amended Lease Agreement Effective January 1, 2004 | Canonsburg Office
Operating Leased Assets [Line Items]
Lease rental expense incurred	$ 1.4	$ 1.4	$ 1.4