Stockholders' Equity - Summary of Changes in Stockholders' Equity (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ equity at beginning of period			$ 295.8	$ 324.1
Comprehensive loss:
Net loss	(49.9)	(9.6)	(64.9)	(19.9)
Foreign currency translation			(0.1)	0.1
Comprehensive loss	(49.9)	(9.6)	(65.0)	(19.8)
Exercise of stock options and warrants			(0.1)	0
Stock-based compensation			4.7	3.9
Employee stock purchase plan and restricted stock units settled in cash			1.8	0
Restricted stock units traded for taxes			(0.1)	(0.1)
Stockholders’ equity at end of period	$ 237.1	$ 308.1	$ 237.1	$ 308.1