Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accrued Liabilities
Accrued payroll and related employee expenses	$ 4,233	$ 4,040
Accrued employee performance bonus	3,574	7,137
Accrued Interest	4,834	5,058
Operating and financing lease liability (current portion)	4,425	521
Other	4,505	7,097
Total accrued expenses	$ 21,571	$ 23,853