Other liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other current liabilities
Lease liability	$ 3,421	$ 3,193
Total other current liabilities	3,421	3,193
Other non-current liabilities
Lease liability	29,183	30,975
Other	1,001	1,001
Total other non-current liabilities	$ 30,184	$ 31,976