Summary of Significant Accounting Policies - Additional Information (Detail) |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2018 |
Dec. 31, 2017 |
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| Product Information [Line Items] | ||
| Cash and cash equivalents, maturity description | 90 days or less | |
| US federal corporate tax rate | 21.00% | 35.00% |
| Limitation of the deduction for net operating losses | 80.00% | |
| Provisional amounts measurement period | 1 year | |
| Maximum [Member] | ||
| Product Information [Line Items] | ||
| Short-term contractual maturities | 1 year | |
| Minimum [Member] | ||
| Product Information [Line Items] | ||
| Long-term contractual maturities | 1 year |
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- Definition Cash Equivalent Maturity Description No definition available.
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- Definition Long Term Investments Maturity Period No definition available.
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- Definition Short Term Investment Contractual Maturity No definition available.
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- Definition Tax cuts and jobs act of 2017 limitation of net operating loss deductions as percentage of current year taxable income. No definition available.
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- Definition Tax cuts and jobs act of 2017 provisional amount measurement period. No definition available.
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- 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. No definition available.
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