Income taxes - Net Operating Loss and Expenditure Credit Carryforwards (Details) - USD ($) $ in Thousands |
6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Jun. 30, 2015 |
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| Net Operating Loss and Expenditure Credit Carryforwards | ||||
| Net operating loss | $ (26,410) | $ (80,661) | $ (72,799) | $ (24,641) |
| Internal Revenue Service (IRS) | ||||
| Net Operating Loss and Expenditure Credit Carryforwards | ||||
| Tax credit carryforwards | 200 | |||
| Her Majesty's Revenue and Customs (HMRC) | ||||
| Net Operating Loss and Expenditure Credit Carryforwards | ||||
| Net operating loss | (135,600) | |||
| Expenditure credit carryforward | $ 600 | |||
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- Definition Amount of expenditure credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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- Definition The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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