Note 2 - Net Income Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 03, 2021	Mar. 28, 2020
Net income	$ 18,813	$ 8,167
Shares used in basic Net income per share (in shares)	136,401	134,253
Dilutive effect of stock options, RSUs, ESPP shares, and equity awards with a market condition or performance condition (in shares)	5,273	3,791
Shares used in diluted Net income per share (in shares)	141,674	138,044
Basic (in dollars per share)	$ 0.14	$ 0.06
Diluted (in dollars per share)	$ 0.13	$ 0.06
Stock options, RSUs, ESPP shares, and equity awards with a market condition or performance condition excluded as they are antidilutive (in shares)	350	1,056