XML 14 R34.htm IDEA: XBRL DOCUMENT
v3.19.3

Investments - Summary of Gross Unrealized Losses and Fair Value of Available-For-Sale Investment Securities in Unrealized Loss Position (Detail) - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Less Than 12 Months, Estimated Fair Value | $ 67,035 | $ 242,961
Less Than 12 Months, Unrealized Losses | (38) | (208)
12 Months or Greater, Estimated Fair Value | 9,830 | 44,637
12 Months or Greater, Unrealized Losses | (2) | (214)
Total, Estimated Fair Value | 76,865 | 287,598
Total, Unrealized Losses | (40) | (422)
Corporate debt securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Less Than 12 Months, Estimated Fair Value | 17,024 | 91,265
Less Than 12 Months, Unrealized Losses | (21) | (130)
12 Months or Greater, Estimated Fair Value | 9,830 | 44,637
12 Months or Greater, Unrealized Losses | (2) | (214)
Total, Estimated Fair Value | 26,854 | 135,902
Total, Unrealized Losses | (23) | (344)
Commercial paper |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Less Than 12 Months, Estimated Fair Value | 50,011 | 151,696
Less Than 12 Months, Unrealized Losses | (17) | (78)
Total, Estimated Fair Value | 50,011 | 151,696
Total, Unrealized Losses | $ (17) | $ (78)

X
- 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
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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 less than twelve months. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_DomesticCorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |