Acquisition (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Jul. 01, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition [Line Items]
Cash consideration to be paid to Audience shareholders and equity award holders				$ 61.6
Revenues		$ 294.6	$ 300.8	774.1	$ 855.3
Net loss		14.9	$ 14.6	$ 46.8	$ 85.9
Audience, Inc.
Business Acquisition [Line Items]
Cash equivalent price (usd per share)	$ 2.51
Consideration transfer, number of shares for each share of acquired entity's shares (in shares)	0.13207
Number of shares issued (in shares)	3,200,000
Cash consideration to be paid to Audience shareholders and equity award holders	$ 61.6
Consideration transferred, number of shares for all unvested equity awards assumed (in shares)	461,371.00
Consideration transferred, enterprise value, net of cash and short-term investments	$ 92.8
Cash and short-term investments	30.5
Revenues		12.1
Net loss		$ 23.3
Consideration transferred, total	$ 123.3
Discount rate used to discount cash flows to present value	27.00%