Consolidated Statement of Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (13,810)	$ (35,570)	$ (33,521)	$ (88,917)
Other comprehensive loss:
Unrealized gain (loss) related to marketable securities, net of tax	1	17	(27)	(3)
Reclassification adjustment for losses (gains) related to marketable securities included in other income (expense), net of tax	36	(54)	38	234
Translation adjustment, net of tax	(678)	(49)	(441)	(55)
Change in actuarial valuation of defined benefit pension	141	2	141	(155)
Comprehensive loss	$ (14,310)	$ (35,654)	$ (33,810)	$ (88,896)