Nature of business (Details)
$ / shares in Units, $ in Thousands
1 Months Ended
Feb. 08, 2016
$ / shares
shares
Feb. 03, 2016
USD ($)
Jan. 15, 2016
Feb. 29, 2016
shares
Mar. 31, 2016
USD ($)
shares
Dec. 31, 2015
USD ($)
shares
Liquidity            
Common stock, shares issued         36,608,136 4,869,829
Accumulated deficit | $         $ (106,089) $ (88,348)
Initial Public Offering            
Liquidity            
Shares sold 6,785,000     6,785,000    
Price to the public | $ / shares $ 16.00          
Aggregate net proceeds | $   $ 97,700        
Reverse stock split     0.3846      
Shares issues upon conversion of preferred stock 24,929,709     24,929,709    
Common stock, shares issued         35,169,842  
Overallotment Option            
Liquidity            
Shares sold 885,000