Net loss per share attributable to common stockholders - Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
|
| Numerator: | ||||
| Net loss attributable to common stockholders, basic and diluted | $ (7,266) | $ (5,937) | $ (17,250) | $ (13,819) |
| Denominator: | ||||
| Weighted average common stock, basic and diluted (in shares) | 37,944 | 36,724 | 37,749 | 36,558 |
| Net loss per share attributable to common stockholders: | ||||
| Basic and diluted (in dollars per share) | $ (0.19) | $ (0.16) | $ (0.46) | $ (0.38) |