Liability Related to the Revenue Interest Purchase Agreement - Summary of Revenue Interest Liability (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Liability From Sale Of Future Revenues [Roll Forward]
Revenue Interests payments	$ (2,263)	$ (110)
Revenue Interest Purchase Agreement (RIPA)
Liability From Sale Of Future Revenues [Roll Forward]
Revenue interest liability, beginning balance	176,604
Oberland funding upon execution of Amendment No. 2, net of issuance costs	49,917
Interest expense recognized	23,310
Revenue Interests payments	(2,263)
Revenue interest liability, ending balance	$ 247,568