Financial Instruments - Schedule of Marketable Securities That Have Been in Continuous Unrealized Loss Position for Less than 12 months and for 12 months or Greater (Detail) - USD ($) $ in Thousands |
Mar. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Cash And Cash Equivalents [Abstract] | ||
| Fair Value of Marketable Securities, Continuous Unrealized Losses, Less than 12 Months | $ 9,968 | $ 13,565 |
| Fair Value of Marketable Securities, Continuous Unrealized Losses, 12 Months or Greater | 7,089 | |
| Fair Value of Marketable Securities, Continuous Unrealized Losses, Total | 17,057 | 13,565 |
| Unrealized Losses, Continuous Unrealized Losses, Less Than 12 Months | (4) | (48) |
| Unrealized Losses, Continuous Unrealized Losses, 12 Months or Greater | (10) | |
| Unrealized Losses, Continuous Unrealized Losses, Total | $ (14) | $ (48) |
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- References No definition available.
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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), in continuous unrealized loss position for more than 12 months. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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