Note 3 - Revenue From Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Revenue	$ 125,905	$ 100,589	$ 241,621	$ 197,905
Percentage of revenue	100.00%	100.00%	100.00%	100.00%
UNITED STATES
Revenue	$ 11,672	$ 9,860	$ 20,782	$ 23,179
Percentage of revenue	9.00%	10.00%	9.00%	12.00%
Other Americas [Member]
Revenue	$ 6,154	$ 4,647	$ 12,887	$ 7,915
Percentage of revenue	5.00%	4.00%	5.00%	4.00%
Americas [Member]
Revenue	$ 17,826	$ 14,507	$ 33,669	$ 31,094
Percentage of revenue	14.00%	14.00%	14.00%	16.00%
CHINA
Revenue	$ 64,821	$ 52,465	$ 131,940	$ 95,964
Percentage of revenue	52.00%	52.00%	54.00%	48.00%
TAIWAN, PROVINCE OF CHINA
Revenue	$ 6,577	$ 7,593	$ 9,391	$ 17,452
Percentage of revenue	5.00%	8.00%	4.00%	9.00%
JAPAN
Revenue	$ 8,836	$ 6,435	$ 16,613	$ 14,434
Percentage of revenue	7.00%	6.00%	7.00%	7.00%
Other Asia [Member]
Revenue	$ 16,221	$ 8,067	$ 26,901	$ 15,403
Percentage of revenue	13.00%	8.00%	11.00%	8.00%
Asia [Member]
Revenue	$ 96,455	$ 74,560	$ 184,845	$ 143,253
Percentage of revenue	77.00%	74.00%	76.00%	72.00%
Europe [Member]
Revenue	$ 11,624	$ 11,522	$ 23,107	$ 23,558
Percentage of revenue	9.00%	12.00%	10.00%	12.00%
Product [Member]
Revenue	$ 122,536	$ 95,996	$ 234,128	$ 189,221
Percentage of revenue	97.00%	96.00%	97.00%	96.00%
Product [Member] \| Sales Channel, Through Intermediary [Member]
Revenue	$ 111,168	$ 85,152	$ 209,947	$ 160,607
Percentage of revenue	88.00%	85.00%	87.00%	81.00%
Product [Member] \| Sales Channel, Directly to Consumer [Member]
Revenue	$ 11,368	$ 10,844	$ 24,181	$ 28,614
Percentage of revenue	9.00%	11.00%	10.00%	15.00%
License and Service [Member]
Revenue	$ 3,369	$ 4,593	$ 7,493	$ 8,684
Percentage of revenue	3.00%	4.00%	3.00%	4.00%