Financial Statement Components - Components of Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	9 Months Ended
	Sep. 28, 2019 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	$ 312,852
Ending Balance Value	335,772
Foreign Currency Translations [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	(2,129)
Current period change	(68)
Ending Balance Value	(2,197)
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	112
Ending Balance Value	330
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance Value	(2,557)
Current period change	44
Ending Balance Value	$ (2,513)