Fair Value Measurements - Changes in the Fair Value of Level 3 Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 18,859	$ 21,983
Additions	0	0
Change in fair value	6,914	3,790
Ending balance	25,773	25,773
Interest make-whole derivative - related party and others
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5	0
Additions	0	0
Change in fair value	58	63
Ending balance	63	63
Bookings Commitment
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	18,854	21,983
Additions	0	0
Change in fair value	6,856	3,727
Ending balance	$ 25,710	$ 25,710