Financial Statement Components - Components of Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	6 Months Ended
	Jun. 29, 2019 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	$ 312,852
Ending Balance Value	328,980
Foreign Currency Translations [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	(2,129)
Current period change	602
Ending Balance Value	(1,527)
Defined Benefit Pension Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	(646)
Ending Balance Value	(646)
Unrealized Income (Loss) on Investment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	218
Current period change	102
Ending Balance Value	320
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	(2,557)
Current period change	704
Ending Balance Value	$ (1,853)