Stockholders' Equity - Summary of Changes in Stockholders' Equity (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ equity at beginning of period			$ 324.1	$ 312.6
Comprehensive loss:
Net loss	(9.9)	(4.2)	(29.8)	(24.4)
Foreign currency translation			0	(0.4)
Comprehensive loss	(10.0)	(4.4)	(29.8)	(24.8)
Additional paid-in-capital from the issuance of common stock for cash			0	97.0
Additional paid-in-capital from the issuance of commons stock in connection with acquisitions			0	23.8
Stock-based compensation			6.0	4.6
Employee stock purchase plan and restricted stock units settled in cash			1.6	(0.4)
Restricted stock units traded for taxes			(0.2)	(0.2)
Stockholders’ equity at end of period	$ 301.7	$ 412.6	$ 301.7	$ 412.6