Net loss per share attributable to common stockholders - Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Numerator: | ||||
| Net loss attributable to common stockholders, basic and diluted | $ (5,709) | $ (4,819) | $ (22,959) | $ (18,638) |
| Denominator: | ||||
| Weighted average common stock, basic and diluted (in shares) | 38,189 | 37,041 | 37,897 | 36,722 |
| Net loss per share attributable to common stockholders: | ||||
| Basic and diluted (in dollars per share) | $ (0.15) | $ (0.13) | $ (0.61) | $ (0.51) |