Balance Sheet Components (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Balance Sheet Related Disclosures [Abstract]
Provisions for excess and obsolete inventory	$ 2,200,000	$ 1,100,000	$ 4,579,000	$ 2,033,000
Amortization expense	1,600,000	$ 1,700,000	3,200,000	$ 3,800,000
Impairment of long-lived assets recognized	0
Equity securities without readily determinable fair value, cumulative downward adjustments for price change and impairment loss	6,200,000		6,200,000
Cumulative upward adjustments for price changes	$ 200,000		$ 200,000