Cash, Cash Equivalents, and Investments - Components of Cash, Cash Equivalents, and Investments (Details) - USD ($) $ in Thousands	Sep. 27, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cash	$ 294,430	$ 155,498
Money market instruments	3,926	15,933
Cash and cash equivalents	298,356	171,431
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	95,365	240,470
Non-current investments, amortized cost of $613,838 and $431,633 in 2020 and 2019, respectively, allowance for expected credit losses of $75 and $0 in 2020 and 2019, respectively	619,343	433,452
Total	1,013,064	845,353
Treasury Bills
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	0	92,914
Long-term investments	270,091	216,334
Corporate Bonds
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	43,436	65,624
Long-term investments	216,451	146,474
Asset-Backed Securities
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	34,536	66,680
Long-term investments	95,007	46,403
Certificate of deposit
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	0	4,328
Sovereign Bonds
Debt Securities, Available-for-sale [Line Items]
Long-term investments	8,410	16,005
Agency Bonds
Debt Securities, Available-for-sale [Line Items]
Long-term investments	28,274	5,914
Municipal Bonds
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	1,307	4,630
Long-term investments	1,110	2,322
Sovereign bonds
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $94,761 and $235,610 in 2020 and 2019, respectively, allowance for expected credit losses of $0 in 2020 and 2019	$ 16,086	$ 6,294

Cash, cash equivalents, short term and long term investments.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as noncurrent.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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