Stock incentive plans - Compensation expenses (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
|
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | $ 3,079 | $ 2,099 | $ 6,684 | $ 3,934 |
| Stock-based compensation expense capitalized | 189 | 209 | 371 | 425 |
| Network operations | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | 531 | 412 | 1,177 | 759 |
| Development and Technology | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | 251 | 129 | 563 | 227 |
| Selling and marketing | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | 458 | 642 | 1,007 | 1,169 |
| General and administrative | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | $ 1,839 | $ 916 | $ 3,937 | $ 1,779 |