v3.10.0.1
Cash and cash equivalents (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Cash and cash equivalents:      
Cash $ 11,689 $ 24,430  
Money market accounts 137,723 2,255  
Total cash and cash equivalents 149,412 26,685  
Interest income $ 742 $ 17 $ 8