Commitments and Contingencies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) item	Dec. 31, 2016 USD ($)
Number of previous claims experienced | item	0
Future minimum unconditional purchase obligations
Net sales and use tax liability	$ 7,962
Sales and use tax liability	12,914	$ 10,108
Sales and use tax receivable	4,952	$ 3,879
Prepaid expense and other current assets
Future minimum unconditional purchase obligations
Sales and use tax receivable	4,952
Accounts Payable and Accrued Liabilities
Future minimum unconditional purchase obligations
Sales and use tax liability	$ 12,914