Basis of Presentation and Summary of Significant Accounting Policies - Summary of Contract Assets and Liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Contract assets:
Balance at January 1, 2018	$ 739
Additions	5,736
Deductions	(1,613)
Balance at September 30, 2018	4,862
Contract liabilities:
Balance at January 1, 2018	100
Additions	3,717
Deductions	(890)
Balance at September 30, 2018	2,927
Reclassified from unbilled revenue to accounts receivable	1,600
Reclassified from deferred revenue to revenue	$ 900
Revenue, performance obligation, timing	one year