Collaborative Arrangements and Licensing Agreements, Traditional Pharmaceutical Alliances and Licensing - Biogen Idec (Neurology) (Details) (Biogen Idec [Member], Agreement Entered into in December 2012 [Member], Neurology [Member], USD $) In Millions, unless otherwise specified	1 Months Ended
	Feb. 28, 2015	Dec. 31, 2012 Program	Mar. 31, 2015
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of programs under which drugs are to be developed and commercialized		3
Upfront fee recorded as deferred revenue		$ 30
Milestone payment earned	10
Cumulative payments received			40.0
Maximum [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Next prospective milestone			14.0
License Fee and Substantive Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable			259.0
Development Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable			59.0
Regulatory Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable			$ 130.0