Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 48,234		$ 50,000	$ 0
Operating lease liability	50,804		52,800
Derecognition of deferred rent	2,800
Derecognition of build-to-suit lease	9,886	$ 0
Derecognition of lease financing obligation	$ 10,500
Cumulative effect adjustment from adoption of ASC 842			556
Accumulated deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment from adoption of ASC 842			$ 556