Share-based compensation - Assumptions used in the Black Scholes option pricing model to determine the fair value of share options (Details) - Stock option - Employees and directors - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
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| Share-based compensation. | ||||
| Risk-free interest rate | 4.30% | 3.90% | 4.10% | 4.30% |
| Expected volatility | 65.60% | 73.50% | 67.80% | 74.10% |
| Expected term (in years) | 6 years 1 month 6 days | 6 years | 6 years 1 month 6 days | 6 years 1 month 6 days |
| Unrecognized compensation expense | ||||
| Total unrecognized compensation expense related to the unvested employee and director | $ 22.9 | $ 22.9 | ||
| Weighted average period for recognition | 2 years 3 months 18 days | |||
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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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