Share-based compensation - Schedule of Stock Option Valuation Assumptions (Details) - $ / shares	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Strike price (in dollars per share)			$ 2.54
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, in %	100.00%		100.00%
Award life, in years	6 years 29 days	6 years 29 days	6 years 29 days	6 years 29 days
Expected dividends	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate, in %, minimum	3.97%	4.24%	3.97%	3.75%
Risk-free interest rate, in %, maximum	4.14%	4.54%	4.43%	4.54%
Employee Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price (in dollars per share)	$ 1.35	$ 3.31	$ 1.35	$ 1.69
Strike price (in dollars per share)	1.35	$ 3.31	1.35	$ 1.69
Expected volatility, in %		95.00%		95.00%
Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price (in dollars per share)	3.59	$ 4.71	3.59	$ 4.86
Strike price (in dollars per share)	$ 3.59	$ 4.71	$ 3.59	$ 4.86

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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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.

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- Definition

The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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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.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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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.

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