Stockholders' Equity - Summary of Changes in Stockholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 27, 2016	Mar. 29, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ equity at beginning of period	$ 254.2	$ 224.3
Comprehensive loss:
Net loss	(22.2)	(16.2)
Change in cumulative translation adjustment	0.0	(0.2)
Comprehensive loss	(22.2)	(16.4)
Stock-based compensation	1.5	2.0
Issuance of common stock for employee stock purchase plan	1.3	1.8
Restricted stock units traded for taxes	(0.1)	(0.1)
Stockholders’ equity at end of period	$ 234.7	$ 211.6