Collaboration and License Agreements (Details) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Nov. 30, 2015	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaboration and License Agreements [Abstract]
Sanofi Upfront Payment			$ 300,000
Sanofi Revenue Allocated to Development Deliverable			113,800
Sanofi Revenue Allocated to License Deliverable			126,800
Sanofi Revenue Recognized						$ 286,000
Sanofi Revenue Allocated to Funding Deliverable			$ 59,400
Ipsen Total Payments To Date				$ 47,200
Ipsen Revenue Recognized					$ 300	4,900
Ipsen product sales						1,300
Settlement Payment from Termination						208,000
Sanofi Termination Agreement						260,000
Sanofi Deferred Revenue from Termination						23,500
Subsequent Event [Line Items]
Settlement Payment from Termination						$ 208,000
Subsequent Event
Collaboration and License Agreements [Abstract]
Settlement Payment from Termination	$ 2,700	$ 12,100
Subsequent Event [Line Items]
Settlement Payment from Termination	$ 2,700	$ 12,100
Legal Fees				$ 2,100