Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Condensed Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Summary of Significant Accounting Policies and Recent Accounting Pronouncements
Net loss	$ (83,597)	$ (61,389)
Changes in deferred revenue	7,607	$ (5,830)
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Summary of Significant Accounting Policies and Recent Accounting Pronouncements
Net loss	(10,294)
Changes in deferred revenue	4,921
Accounting Standards Update 2014-09 | Calculated under Revenue Guidance in Effect before Topic 606
Summary of Significant Accounting Policies and Recent Accounting Pronouncements
Net loss	(73,303)
Changes in deferred revenue	$ 2,686