Reconciliation of Tax Computed at Statutory Federal Rate to Income Tax Expense in Statements of Operations (Parenthetical) (Detail) |
12 Months Ended | |||
|---|---|---|---|---|
Jan. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Schedule of Effective Tax Rate Reconciliation [Line Items] | ||||
| U.S. federal statutory tax rate | 34.00% | 34.00% | 34.00% | |
| Scenario, forecast | ||||
| Schedule of Effective Tax Rate Reconciliation [Line Items] | ||||
| U.S. federal statutory tax rate | 21.00% | |||
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- Definition Schedule of Effective Tax Rate Reconciliation [Line Items] No definition available.
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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