v3.20.2

Investments - Summary of Investments (Detail) - USD ($) $ in Thousands | Jun. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 2,264,870 | $ 1,921,133
Gross Unrealized Gains | 17,828 | 7,735
Gross Unrealized Losses | (529) | (219)
Estimated Fair Value | 2,282,169 | 1,928,649
Commercial paper |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 414,613 | 101,416
Gross Unrealized Gains | 521 | 83
Gross Unrealized Losses | (31) | (9)
Estimated Fair Value | 415,103 | 101,490
Corporate notes and bonds |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 1,571,083 | 1,654,166
Gross Unrealized Gains | 15,645 | 7,360
Gross Unrealized Losses | (493) | (196)
Estimated Fair Value | 1,586,235 | 1,661,330
Certificates of deposit |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 20,077 | 38,007
Gross Unrealized Gains | 21 | 38
Gross Unrealized Losses | 0 | 0
Estimated Fair Value | 20,098 | 38,045
U.S. government and agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 259,097 | 127,544
Gross Unrealized Gains | 1,641 | 254
Gross Unrealized Losses | (5) | (14)
Estimated Fair Value | $ 260,733 | $ 127,784

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- Definition 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). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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