Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Earnings Per Share
Net income	$ 19,265	$ 83,591	$ 47,092
Shares used in computing basic earnings per share	43,346	43,159	42,446
Effect of dilutive securities:
Stock-based awards and convertible debt	944	885	886
Shares used in computing diluted earnings per share	44,290	44,044	43,332
Earnings per share:
Basic (in dollars per share)	$ 0.44	$ 1.94	$ 1.11
Diluted (in dollars per share)	$ 0.43	$ 1.90	$ 1.09
Shares attributable to dilutive effect of conversion of debt securities	400	100	0