Cash, Cash Equivalents, Short-Term and Long-Term Investments - Additional Information (Detail) |
12 Months Ended |
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Dec. 31, 2018 | |
| Maximum [Member] | |
| Cash Cash Equivalents Short Term And Long Term Investments [Line Items] | |
| Long-term investments maturity period | 2 years |
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- Definition Cash, cash equivalents, short-term and long-term investments. No definition available.
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| X | ||||||||||
- Definition Long-term investments maturity period. No definition available.
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- Details
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