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Fair Value of Financial Instruments - Available-for-sale investments (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 28, 2019 | Dec. 29, 2018
Cost |  |
Due in one year or less, Cost | $ 381,583 |
Due after one year through ten years, Cost | 196,702 |
Due after ten years, Cost | 18,900 |
Total Cost | 597,185 |
Fair Value |  |
Due in one year or less, Fair Value | 382,259 |
Due after one year through ten years, Fair Value | 197,370 |
Due after ten years, Fair Value | 18,547 |
Total Fair Value | 598,176 |
Continuous unrealized loss position, Fair Value |  |
Fair value of available-for-sale securities, continuous loss position for less than twelve months | 80,063 | $ 125,977
Fair value of available-for-sale securities, continuous loss position for twelve months or greater | 12,850 | 170,765
Total fair value of available-for-sale securities, continuous loss position | 92,913 | 296,742
Continuous unrealized loss position, Gross Unrealized Losses |  |
Available-for-sale securities, continuous loss position for less than 12 months, gross unrealized losses | (100) | (283)
Available-for-sale securities, continuous loss position for 12 months or greater, gross unrealized losses | (360) | (1,272)
Available-for-sale securities, total gross unrealized losses | (460) | (1,555)
Other than temporary impairment losses |  |
Other-than-temporary impairment losses | 0 |
Government debt securities |  |
Continuous unrealized loss position, Fair Value |  |
Fair value of available-for-sale securities, continuous loss position for less than twelve months | 11,947 | 13,278
Fair value of available-for-sale securities, continuous loss position for twelve months or greater | 7,183 | 88,696
Total fair value of available-for-sale securities, continuous loss position | 19,130 | 101,974
Continuous unrealized loss position, Gross Unrealized Losses |  |
Available-for-sale securities, continuous loss position for less than 12 months, gross unrealized losses | (19) | (10)
Available-for-sale securities, continuous loss position for 12 months or greater, gross unrealized losses | (7) | (583)
Available-for-sale securities, total gross unrealized losses | (26) | (593)
Corporate debt securities |  |
Continuous unrealized loss position, Fair Value |  |
Fair value of available-for-sale securities, continuous loss position for less than twelve months | 68,116 | 112,699
Fair value of available-for-sale securities, continuous loss position for twelve months or greater | 20 | 76,310
Total fair value of available-for-sale securities, continuous loss position | 68,136 | 189,009
Continuous unrealized loss position, Gross Unrealized Losses |  |
Available-for-sale securities, continuous loss position for less than 12 months, gross unrealized losses | (81) | (273)
Available-for-sale securities, continuous loss position for 12 months or greater, gross unrealized losses |  | (448)
Available-for-sale securities, total gross unrealized losses | (81) | (721)
Auction rate securities |  |
Continuous unrealized loss position, Fair Value |  |
Fair value of available-for-sale securities, continuous loss position for twelve months or greater | 5,647 | 5,759
Total fair value of available-for-sale securities, continuous loss position | 5,647 | 5,759
Continuous unrealized loss position, Gross Unrealized Losses |  |
Available-for-sale securities, continuous loss position for 12 months or greater, gross unrealized losses | (353) | (241)
Available-for-sale securities, total gross unrealized losses | $ (353) | $ (241)

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- Definition This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature after one year and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor as trading securities. + References No definition available. + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454 + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 + Details
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