Share-based compensation - Options (Details) - $ / shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Share-based compensation | ||||
| Number of options granted (in shares) | 1,252,176 | 1,768,243 | 20,203,152 | 15,343,797 |
| Weighted average fair value (in dollars per share) | $ 0.42 | $ 0.89 | $ 0.35 | $ 0.70 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Gross number of share options (or share units) granted during the period. No definition available.
|
| X | ||||||||||
- 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
|