Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 28, 2019
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	$ 643,670	$ 431,916
Gross Unrealized Gains	761	143
Gross Unrealized Losses	(120)	(78)
Debt Securities, Available-for-sale	644,311	431,981
Cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	79,281	249,952
Debt Securities, Available-for-sale	79,281	249,952
Cash equivalents [Member] \| Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	56,855	185,666
Debt Securities, Available-for-sale	56,855	185,666
Cash equivalents [Member] \| Time deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	19,676	64,286
Debt Securities, Available-for-sale	19,676	64,286
Cash equivalents [Member] \| Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	1,600
Debt Securities, Available-for-sale	1,600
Cash equivalents [Member] \| Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	1,150
Debt Securities, Available-for-sale	1,150
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	472,784	85,778
Gross Unrealized Gains	581	52
Gross Unrealized Losses	(42)	(11)
Debt Securities, Available-for-sale	473,323	85,819
Short-term investments [Member] \| Time deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	21,248	2,506
Debt Securities, Available-for-sale	21,248	2,506
Short-term investments [Member] \| Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	259,000
Gross Unrealized Gains	22
Gross Unrealized Losses	(7)
Debt Securities, Available-for-sale	259,015
Short-term investments [Member] \| Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	192,536	83,272
Gross Unrealized Gains	559	52
Gross Unrealized Losses	(35)	(11)
Debt Securities, Available-for-sale	193,060	83,313
Long-term investments [Member] \| Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	91,605	96,186
Gross Unrealized Gains	180	91
Gross Unrealized Losses	(78)	(67)
Debt Securities, Available-for-sale	$ 91,707	$ 96,210

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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