Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Earnings (loss) per share:
Loss from continuing operations	$ (18,491)	$ (36,045)	$ (43,647)	$ (67,436)
Shares used in computing basic earnings (loss) per share	44,803	43,761	44,481	43,699
Shares used in computing diluted loss per share	44,803	43,761	44,481	43,699
Earnings (loss) per share:
Loss per share, Basic (in dollars per share)	$ (0.41)	$ (0.82)	$ (0.98)	$ (1.54)
Loss per share, Diluted (in dollars per share)	$ (0.41)	$ (0.82)	$ (0.98)	$ (1.54)
Shares excluded from calculation of diluted shares due to loss from continuing operations	1,000	300	1,300	500
Shares attributable to dilutive effect of conversion of debt securities	500	0	800	200
RSUs and MSUs
Earnings (loss) per share:
Anti-dilutive securities excluded from computation of diluted earnings (loss) per share	0	400	0	300