Income Taxes - Source of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Income Tax Disclosure [Abstract] | |||
| Domestic | $ (24,626) | $ (16,926) | $ (9,022) |
| X | ||||||||||
- Definition The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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