Balance Sheet Components (Property and Equipment) (Details) - USD ($) $ in Thousands	Sep. 28, 2019	Dec. 29, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment, net	$ 40,163	$ 34,883
United States
Property, Plant and Equipment [Line Items]
Total property and equipment, net	33,303	27,353
Foreign countries
Property, Plant and Equipment [Line Items]
Total property and equipment, net	6,860	7,530
China
Property, Plant and Equipment [Line Items]
Total property and equipment, net	1,698	2,360
Philippines
Property, Plant and Equipment [Line Items]
Total property and equipment, net	3,298	3,319
Taiwan
Property, Plant and Equipment [Line Items]
Total property and equipment, net	1,268	949
Japan
Property, Plant and Equipment [Line Items]
Total property and equipment, net	202	324
Other
Property, Plant and Equipment [Line Items]
Total property and equipment, net	$ 394	$ 578