Condensed Financial Statements - Summary of Components of Interest, Net (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
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| Condensed Financial Information Disclosure [Abstract] | ||
| Interest expense | $ (370) | $ (235) |
| Interest income | 542 | 167 |
| Interest, net | $ 172 | $ (68) |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of the cost of borrowed funds accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The net amount of nonoperating interest income (expense). No definition available.
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| X | ||||||||||
- Definition Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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