Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accrued liabilities
Accrued payroll and other compensation	$ 5,775	$ 4,726
Accrued state sales taxes	3,215	3,939
Accrued vendor charges	236	1,281
Accrued interest		717
Other	2,995	2,165
Total accrued liabilities	$ 12,221	$ 12,828