Revenue from Contracts with Customers - Schedule of Changes in Contract Liabilities Balance (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Movement in Contract with Customer, Liability [Roll Forward]
Deferred revenue at beginning of the period	$ 1,111
Increases due to cash received from customers	5,980
Decreases due to recognition of revenue	(5,036)
Deferred revenue end of the period	$ 2,055