Note 3 - Revenue From Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2021	Sep. 26, 2020	Oct. 02, 2021	Sep. 26, 2020
Revenue	$ 131,911	$ 103,042	$ 373,532	$ 300,947
Percentage of revenue	100.00%	100.00%	100.00%	100.00%
UNITED STATES
Revenue	$ 11,022	$ 10,455	$ 31,804	$ 33,634
Percentage of revenue	8.00%	10.00%	8.00%	11.00%
Other Americas [Member]
Revenue	$ 9,239	$ 4,857	$ 22,126	$ 12,772
Percentage of revenue	7.00%	5.00%	6.00%	4.00%
Americas [Member]
Revenue	$ 20,261	$ 15,312	$ 53,930	$ 46,406
Percentage of revenue	15.00%	15.00%	14.00%	15.00%
CHINA
Revenue	$ 76,692	$ 58,122	$ 208,632	$ 154,086
Percentage of revenue	58.00%	56.00%	56.00%	51.00%
TAIWAN, PROVINCE OF CHINA
Revenue	$ 4,549	$ 7,505	$ 13,940	$ 24,957
Percentage of revenue	4.00%	7.00%	4.00%	8.00%
JAPAN
Revenue	$ 7,877	$ 4,346	$ 24,490	$ 18,780
Percentage of revenue	6.00%	4.00%	6.00%	6.00%
Other Asia [Member]
Revenue	$ 9,779	$ 9,766	$ 36,680	$ 25,169
Percentage of revenue	7.00%	10.00%	10.00%	9.00%
Asia [Member]
Revenue	$ 98,897	$ 79,739	$ 283,742	$ 222,992
Percentage of revenue	75.00%	77.00%	76.00%	74.00%
Europe [Member]
Revenue	$ 12,753	$ 7,991	$ 35,860	$ 31,549
Percentage of revenue	10.00%	8.00%	10.00%	11.00%
Product [Member]
Revenue	$ 127,417	$ 96,650	$ 361,545	$ 285,871
Percentage of revenue	97.00%	94.00%	97.00%	95.00%
Product [Member] | Sales Channel, Through Intermediary [Member]
Revenue	$ 118,227	$ 84,409	$ 328,174	$ 245,016
Percentage of revenue	90.00%	82.00%	88.00%	81.00%
Product [Member] | Sales Channel, Directly to Consumer [Member]
Revenue	$ 9,190	$ 12,241	$ 33,371	$ 40,855
Percentage of revenue	7.00%	12.00%	9.00%	14.00%
License and Service [Member]
Revenue	$ 4,494	$ 6,392	$ 11,987	$ 15,076
Percentage of revenue	3.00%	6.00%	3.00%	5.00%