Collaboration Agreements (Details) - USD ($) $ in Thousands			1 Months Ended		12 Months Ended
	Oct. 02, 2015	Dec. 16, 2014	Dec. 31, 2014	Feb. 28, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income					$ 3,854	$ 10,132	$ 24,236
AstraZeneca [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income							16,000
Alnylam [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial payment				$ 25,000
Maximum payment				180,000
Milestone payment			$ 10,000	$ 10,000
SciClone [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income					600	8,200
Initial payment		$ 10,000
Milestone payment		$ 50,500
SymBio Pharmaceuticals Ltd [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income					$ 2,500	$ 600
Initial payment	$ 10,000
Milestone payment	$ 20,900
Boston Scientific Corporation [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income							$ 5,000