v3.8.0.1
Cash and cash equivalents (Details) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Sep. 30, 2016
Dec. 31, 2015
Cash and cash equivalents:        
Cash $ 19,384 $ 17,246    
Money market accounts 2,250 2,239    
Total cash and cash equivalents $ 21,634 $ 19,485 $ 13,200 $ 14,718