Share-based compensation - Options (Details) |
3 Months Ended | ||
|---|---|---|---|
|
Mar. 31, 2019
$ / shares
shares
|
Mar. 31, 2019
£ / shares
shares
|
Mar. 31, 2018
$ / shares
shares
|
|
| Number of options granted (in shares) | shares | 10,807,200 | 10,807,200 | 9,994,656 |
| Weighted average fair value (in dollars per share) | $ / shares | $ 0.55 | $ 0.75 | |
| RSU | |||
| Number of options granted (in shares) | shares | 6,498,126 | 6,498,126 | 6,552,636 |
| Weighted average fair value (in dollars per share) | $ / shares | $ 0.94 | $ 1.34 | |
| 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% | |
| 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://fasb.org/us-gaap/role/ref/legacyRef
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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://fasb.org/us-gaap/role/ref/legacyRef
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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://fasb.org/us-gaap/role/ref/legacyRef
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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://fasb.org/us-gaap/role/ref/legacyRef
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