Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accounts Receivable
Trade accounts receivable	$ 38,716	$ 39,004
Unbilled accounts receivable	6,882	4,223
Accounts receivable, gross	45,598	43,227
Less allowance for doubtful accounts	(281)	(395)
Accounts receivable, net	$ 45,317	$ 42,832