Collaborative Arrangements and Licensing Agreements, Traditional Pharmaceutical Alliances and Licensing - Biogen Idec (ISIS-DMPK) (Details) - Biogen Idec [Member] - ISIS-DMPK [Member] - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2012	Jun. 30, 2015
Agreement Entered into in June 2012 [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront fee recorded as deferred revenue	$ 12.0
Cumulative payments received		$ 36.0
Agreement Entered into in June 2012 [Member] | Phase 1 Study [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Next prospective milestone		2.8
Agreement Entered into in June 2012 [Member] | Phase 2 Study [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Next prospective milestone		35.0
Agreement Entered into in June 2012 [Member] | License Fee and Substantive Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable		263.0
Agreement Entered into in June 2012 [Member] | Development Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable		63.0
Agreement Entered into in June 2012 [Member] | Regulatory Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable		130.0
Agreement Amended in June 2015 [Member] | Phase 1 Study [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable		$ 4.2