Provision for Income Taxes - Schedule of reconciliation of beginning and ending amounts of unrecognized tax benefits (Details) - USD ($) $ in Thousands |
12 Months Ended | |
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Dec. 31, 2017 |
Dec. 31, 2016 |
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| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | ||
| Unrecognized tax benefits, beginning balance | $ 9,412 | $ 6,864 |
| Increases related to tax positions taken during a prior year | 0 | 0 |
| Decreases related to tax positions taken during a prior year | (37) | (13) |
| Increases related to tax positions taken during the current year | 2,995 | 2,561 |
| Unrecognized tax benefits, ending balance | $ 12,370 | $ 9,412 |
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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