Share-based compensation - Options (Details) |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
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Jun. 30, 2018
$ / shares
shares
|
Jun. 30, 2017
$ / shares
shares
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Jun. 30, 2018
$ / shares
shares
|
Jun. 30, 2018
£ / shares
shares
|
Jun. 30, 2017
$ / shares
shares
|
|
| Number of options granted (in shares) | shares | 1,435,685 | 1,252,176 | 11,430,341 | 11,430,341 | 20,203,152 |
| Weighted average fair value (in dollars per share) | $ / shares | $ 1.18 | $ 0.42 | $ 0.80 | $ 0.35 | |
| RSU | |||||
| Number of options granted (in shares) | shares | 151,056 | 6,703,692 | 6,703,692 | ||
| Weighted average fair value (in dollars per share) | $ / shares | $ 1.88 | $ 1.35 | |||
| Exercise price | £ / shares | £ 0.001 | ||||
| Vesting period (in years) | 4 years | 4 years | |||
| Contractual term (in years) | 10 years | 10 years | |||
| First anniversary | RSU | |||||
| Vesting percentage (as a percent) | 25.00% | 25.00% | |||
| Annual installments over the following three years | RSU | |||||
| Vesting percentage (as a percent) | 75.00% | 75.00% | |||
| X | ||||||||||
- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Gross number of share options (or share units) granted during the period. No definition available.
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average price at which option holders acquired shares when converting their stock options into shares. No definition available.
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- Definition Percentage of vesting of share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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