Summary of Significant Accounting Policies - Schedule of Allowance for Doubtful Accounts - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for doubtful accounts, beginning balance	$ 1,269	$ 763
Additions	3,400	2,029
Write-offs	(3,417)	(1,523)
Allowance for doubtful accounts, ending balance	$ 1,252	$ 1,269