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Stock-Based Awards - Summary of Option Activity (Parenthetical) (Detail) | 12 Months Ended
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Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Expire start date on options | Aug. 24, 2018
Expire end date on options | Nov. 15, 2021

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- Definition Share Based Compensation Arrangement By Share Based Payment Award Expiration Period End Date + References No definition available. + Details
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