Commitments and Contingencies - Summary of Lease Exit Accruals (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Lease Exit [Roll Forward]
Balance at December 31, 2018	$ 4,634
Effect of adoption of ASC 842, “Leases”	(4,634)
Balance at June 30, 2019	$ 0