Fair value measurement (Details) - Recurring basis - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Assets: | ||
| Money market accounts | $ 2,230 | $ 5,602 |
| Marketable securities | 1,614 | |
| Total assets | 2,230 | 7,216 |
| Liabilities: | ||
| Contingent consideration | 131 | |
| Total liabilities | 131 | |
| Level 1 | ||
| Assets: | ||
| Money market accounts | 2,230 | 5,602 |
| Marketable securities | 0 | |
| Total assets | 2,230 | 5,602 |
| Liabilities: | ||
| Contingent consideration | 0 | |
| Total liabilities | 0 | |
| Level 2 | ||
| Assets: | ||
| Money market accounts | 0 | 0 |
| Marketable securities | 1,614 | |
| Total assets | 0 | 1,614 |
| Liabilities: | ||
| Contingent consideration | 0 | |
| Total liabilities | 0 | |
| Level 3 | ||
| Assets: | ||
| Money market accounts | 0 | 0 |
| Marketable securities | 0 | |
| Total assets | $ 0 | 0 |
| Liabilities: | ||
| Contingent consideration | 131 | |
| Total liabilities | $ 131 |