Collaboration, License, Co-Promotion and Other Commercial Agreements - Co-Promotion Agreements (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Aug. 09, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Collaboration, License and Co-Promotion Agreements
Revenue		$ 89,432	$ 102,215	$ 169,375	$ 170,945
Collaborative arrangements and active pharmaceutical ingredient
Collaboration, License and Co-Promotion Agreements
Deferred revenue		900		900		$ 900
Collaborative arrangements revenue
Collaboration, License and Co-Promotion Agreements
Revenue		89,423	$ 77,322	163,868	$ 143,474
Alnylam | Collaborative arrangement, promotion agreements
Collaboration, License and Co-Promotion Agreements
Total annual service fees due	$ 9,500
Term of agreement	3 years
Revenue		1,100		2,000
Deferred revenue		900		900		$ 900
Alnylam | Royalty
Collaboration, License and Co-Promotion Agreements
Revenue		200		200
Alnylam | Service fees
Collaboration, License and Co-Promotion Agreements
Revenue		$ 900		$ 1,800