Share-based compensation - Options (Details) - $ / shares |
3 Months Ended | |
|---|---|---|
Mar. 31, 2020 |
Mar. 31, 2019 |
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| Share-based compensation | ||
| Number of options granted (in shares) | 10,229,280 | 10,807,200 |
| Weighted average fair value (in dollars per share) | $ 0.51 | $ 0.55 |
| Number of RSU-style options granted | 6,060,696 | 6,498,126 |
| Weighted average fair value of RSU-style options granted | $ 0.74 | $ 0.94 |
| X | ||||||||||
- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the nominal exercise price. No definition available.
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- Definition Gross number of share options (or share units) granted with nominal exercise price during the period. No definition available.
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- References No definition available.
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| X | ||||||||||
- 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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