Organization and basis of presentation (Details) $ in Thousands |
Jun. 30, 2015
USD ($)
treatment
|
Dec. 31, 2014
USD ($)
|
---|---|---|
Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||
Accumulated deficit | $ | $ (129,394) | $ (94,698) |
Number of treatments | 1 | |
Potential treatments in development | 2 |