Debt - Summary of Information about the Equity and Liability Components of Notes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 17, 2021	Apr. 08, 2021	Dec. 31, 2020	Feb. 10, 2020	Apr. 15, 2019
Debt Instrument [Line Items]
Total notes payable	$ 6,799,000		$ 6,799,000				$ 3,082,000
Contractual interest expense	3,284,000	$ 1,017,000	7,497,000	$ 3,009,000
Amortization of debt issuance costs and discount	2,118,000	1,126,000	5,035,000	3,205,000
Total interest expense	5,402,000	$ 2,143,000	12,532,000	$ 6,214,000
Convertible Notes
Debt Instrument [Line Items]
Principal amount of notes outstanding							133,750,000		$ 80,000,000
Unamortized discount and unamortized debt issuance cost							(28,605,000)
Total notes payable							105,145,000
Convertible Notes | Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Principal amount of notes outstanding	13,750,000		13,750,000				13,750,000
Unamortized discount and unamortized debt issuance cost	(2,089,000)		(2,089,000)				(2,619,000)
Total notes payable	11,661,000		11,661,000				11,131,000
Convertible Notes | Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Principal amount of notes outstanding	120,000,000		120,000,000				120,000,000	$ 120,000,000
Unamortized discount and unamortized debt issuance cost	(22,918,000)		(22,918,000)				(25,986,000)
Total notes payable	97,082,000		97,082,000				$ 94,014,000
Convertible Notes | Convertible Senior Notes Due 2027
Debt Instrument [Line Items]
Principal amount of notes outstanding	265,000,000		265,000,000		$ 265,000,000
Unamortized discount and unamortized debt issuance cost	(71,587,000)		(71,587,000)
Total notes payable	193,413,000		193,413,000
Credit Facility | Owl Rock Credit Agreement
Debt Instrument [Line Items]
Principal amount of notes outstanding	398,750,000		398,750,000			$ 180,000,000
Unamortized discount and unamortized debt issuance cost	(96,594,000)		(96,594,000)
Total notes payable	$ 302,156,000		$ 302,156,000