Collaborative Arrangements and Licensing Agreements, Pfizer (Details) - Akcea [Member] - USD ($) shares in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Oct. 31, 2019	Dec. 31, 2019	Mar. 31, 2019
Collaborative Arrangement and Licensing Agreement [Abstract]
Sublicense fee paid for license of drug			$ 75
Additional shares of Akcea stock received (in shares)			2.8
Pfizer [Member] | Forecast [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Sublicense fee paid for license of drug		$ 125
Additional shares of Akcea stock received (in shares)		6.9
Pfizer [Member] | Subsequent Event [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront license fee to be received	$ 250
Maximum amount of payments receivable for development, regulatory and sales milestones	$ 1,300
Royalty percentage received on net sales of drug	20.00%