Changes in Stockholders' Equity and Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 305,520
Net loss for the nine months ended October 1, 2016			(45,935)
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 adjustments, net of tax	(138)	(697)	(579)	(752)
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax			2,471
Stock-based compensation expense related to stock options, ESPP and RSUs			12,106
Defined benefit pension, net of actuarial losses	0	$ (1)	141	$ (156)
Ending balance	273,674		273,674
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			1,187
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax			23
Ending balance	1,210		1,210
Additional Paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			660,089
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax			2,448
Stock-based compensation expense related to stock options, ESPP and RSUs			12,106
Ending balance	674,643		674,643
Accumulated deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(352,846)
Net loss for the nine months ended October 1, 2016			(45,935)
Defined benefit pension, net of actuarial losses			0
Ending balance	(398,781)		(398,781)
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(2,910)
Unrealized loss related to marketable securities, net of tax			(88)
Reclassification adjustment for losses related to marketable securities included in other income (expense), net of tax			38
Translation adjustments, net of tax			(579)
Defined benefit pension, net of actuarial losses			141
Ending balance	$ (3,398)		$ (3,398)