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Schedule of Unrealized Loss on Available-for-Sale Investments (Detail) - USD ($) $ in Thousands | Dec. 28, 2019 | Dec. 29, 2018
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Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value | $ 10,525 | $ 45,960
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss | 47 | 354
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value | 4,260 | 43,423
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss | 3 | 863
Available-for-sale investments with unrealized losses, Fair Value, Total | 14,785 | 89,383
Available-for-sale investments with unrealized losses, Unrealized Loss, Total | 50 | 1,217
Asset-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value | 571 |
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss | 1 |
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value | 0 | 620
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss | 0 | 4
Available-for-sale investments with unrealized losses, Fair Value, Total | 571 | 620
Available-for-sale investments with unrealized losses, Unrealized Loss, Total | 1 | 4
Corporate bonds and direct obligations of government agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value | 8,728 | 45,960
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss | 41 | 354
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value | 4,260 | 42,803
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss | 3 | 859
Available-for-sale investments with unrealized losses, Fair Value, Total | 12,988 | 88,763
Available-for-sale investments with unrealized losses, Unrealized Loss, Total | 44 | $ 1,213
U.S. Treasury obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value | 1,226 |
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss | 5 |
Available-for-sale investments with unrealized losses, Fair Value, Total | 1,226 |
Available-for-sale investments with unrealized losses, Unrealized Loss, Total | $ 5 |

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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. + References No definition available. + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27337-111563 + Details
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