Consolidated Statement of Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (12,414)	$ (24,862)	$ (45,935)	$ (113,779)
Other comprehensive loss:
Unrealized loss related to marketable securities, net of tax	(61)	(130)	(88)	(133)
Reclassification adjustment for losses related to marketable securities included in other income (expense), net of tax	0	209	38	443
Translation adjustment, net of tax	(138)	(697)	(579)	(752)
Change in actuarial valuation of defined benefit pension	0	(1)	141	(156)
Comprehensive loss	$ (12,613)	$ (25,481)	$ (46,423)	$ (114,377)