Royalty Purchase Liability - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2018	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	May 31, 2020
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price		$ 125,751		$ 125,751				$ 63,369
Royalty purchase price				57,500	$ 20,000
Noncash interest expense				$ 4,882	3,625
Warrant expiration term		6 years		6 years
Fair value of equity classified warrants		$ 4,700		$ 4,700
Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price	$ 80,000
Royalty purchase price				117,500
Outstanding amount of royalty agreement									$ 20,000
Noncash interest expense		$ 2,300	$ 1,200	$ 4,900	$ 3,600
Effective interest rate		8.30%		8.30%
Royalty Agreements | First Tranche
Royalty Purchase Liability [Line Items]
Royalty purchase price	$ 20,000
Royalty Agreements | Fifth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement							$ 20,000
Royalty Agreements | Fourth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement						$ 37,500
Amended Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price									117,500
Outstanding amount of royalty agreement									37,500
Amended Royalty Agreements | Fifth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement									$ 20,000