Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued Liabilities
Accrued payroll and related employee expenses	$ 5,078	$ 3,954
Accrued employee performance bonus	2,734	3,920
Accrued rebates	3,559	1,573
Sales tax liability	2,700
Accrued interest	4,771	4,951
Operating and financing lease liability (current portion)	4,592	4,494
Other	5,284	3,928
Total accrued expenses	$ 28,718	$ 22,820