- Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Basic and Diluted Net Income Per Share
Net income	$ 20,041	$ 35,532	$ 7,207	$ 22,520	$ 25,191	$ 31,929	$ 10,471	$ 20,401	$ 85,300	$ 87,992	$ 50,964
Weighted-average shares outstanding									28,097	27,692	27,611
Dilutive effect of employee stock plans									638	948	1,142
Diluted weighted-average shares outstanding									28,735	28,640	28,753
Basic									$ 3.04	$ 3.18	$ 1.85
Diluted	$ 0.70	$ 1.24	$ 0.25	$ 0.78	$ 0.88	$ 1.12	$ 0.37	$ 0.71	$ 2.97	$ 3.07	$ 1.77