Note 2 - Net Income Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Net income	$ 21,838	$ 10,629	$ 40,651	$ 18,796
Shares used in basic Net income per share (in shares)	136,388	134,857	136,394	134,555
Dilutive effect of stock options, RSUs, ESPP shares, and equity awards with a market condition or performance condition (in shares)	5,103	4,345	5,243	4,196
Shares used in diluted Net income per share (in shares)	141,491	139,202	141,637	138,751
Basic (in dollars per share)	$ 0.16	$ 0.08	$ 0.30	$ 0.14
Diluted (in dollars per share)	$ 0.15	$ 0.08	$ 0.29	$ 0.14
Stock options, RSUs, ESPP shares, and equity awards with a market condition or performance condition excluded as they are antidilutive (in shares)	124	579	96	658