CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (70,562)	$ (54,099)	$ (159,233)
Other comprehensive loss:
Unrealized loss related to marketable securities, net of tax	(73)	(172)	(69)
Reclassification adjustment for losses related to marketable securities included in other (expense) income	252	79	442
Translation adjustment loss, net of tax	2,620	(1,303)	(1,243)
Change in actuarial valuation of defined benefit pension	(95)	150	(156)
Comprehensive loss	$ (67,858)	$ (55,345)	$ (160,259)