Stockholders' Equity - Summary of Changes in Stockholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ equity at beginning of period			$ 224.3	$ 295.8
Comprehensive income (loss):
Net income (loss)	$ 55.1	$ (10.9)	23.8	(75.8)
Change in cumulative translation adjustment	0.1	(0.1)	0.2	(0.2)
Comprehensive income (loss)	55.2	(11.0)	24.0	(76.0)
Exercise of stock options and warrants			0.0	(0.1)
Stock-based compensation			5.8	7.6
Employee stock purchase plan and restricted stock units settled in cash			4.0	3.9
Restricted stock units traded for taxes			(0.5)	(0.2)
Stockholders’ equity at end of period	$ 257.6	$ 231.0	$ 257.6	$ 231.0