Stock incentive plans - Compensation expense (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | $ 2,054 | $ 3,155 | $ 6,434 | $ 9,227 |
| Stock-based compensation expense capitalized | 224 | 208 | 689 | 600 |
| Network operations | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | 387 | 549 | 1,241 | 1,602 |
| Development and technology | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | 325 | 323 | 962 | 915 |
| Selling and marketing | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | 578 | 511 | 1,655 | 1,377 |
| General and administrative | ||||
| Recognized stock-based compensation expense | ||||
| Total stock-based compensation | $ 764 | $ 1,772 | $ 2,576 | $ 5,333 |