Stock Based Compensation - Additional Information (Detail) - USD ($) |
3 Months Ended | |
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Mar. 31, 2018 |
Mar. 31, 2017 |
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| Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | ||
| Stock-based compensation expense | $ 643,000 | $ 26,000 |
| Unrecognized compensation cost related to unvested stock-based awards granted to employees under the equity incentive plans | $ 9,200,000 | |
| Unrecognized compensation cost related to unvested stock-based awards granted to employees under the equity incentive plans, period for recognition | 3 years 4 months 24 days | |
| Total intrinsic value of stock options exercised | $ 1,600,000 | |
| Cash received from stock option exercises | 148,000 | $ 0 |
| Tax benefit realized upon exercise of option | $ 0 | |
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Unrecognized cost of unvested share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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