Income Taxes - Change in Valuation Allowance (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Deferred Tax Assets, Valuation Allowance [Roll Forward] | |||
| Valuation allowance, beginning balance | $ 85,393 | $ 43,269 | $ 53,199 |
| Increase (decrease) in valuation allowance | 76,118 | 42,124 | (9,930) |
| Valuation allowance, ending balance | $ 161,511 | $ 85,393 | $ 43,269 |
| X | ||||||||||
- Definition Deferred Tax Assets, Valuation Allowance [Roll Forward] No definition available.
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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