Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2021	Oct. 03, 2020	Oct. 02, 2021	Oct. 03, 2020
Earnings (Loss) Per Share
Loss from continuing operations	$ (19,740)	$ (26,702)	$ (63,387)	$ (94,138)
Shares used in computing basic loss per share	43,385	43,815	44,103	43,737
Shares used in computing diluted loss per share	43,385	43,815	44,103	43,737
Earnings (loss) per share:
Loss per share, Basic (in dollars per share)	$ (0.45)	$ (0.61)	$ (1.44)	$ (2.15)
Loss per share, Diluted (in dollars per share)	$ (0.45)	$ (0.61)	$ (1.44)	$ (2.15)
Shares excluded from calculation of diluted shares due to loss from continuing operations	1,200	500	1,300	500
Shares attributable to dilutive effect of conversion of debt securities	700	100	800	200