Collaboration Agreements (Details) - USD ($) $ in Thousands			1 Months Ended		3 Months Ended
	Oct. 02, 2015	Dec. 16, 2014	Dec. 31, 2014	Feb. 28, 2013	Mar. 31, 2016	Mar. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income					$ 975	$ 8,388
Alnylam Pharmaceuticals, Inc. [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial payment				$ 25,000
Maximum payment for success-based development and commercialization milestones				$ 180,000
Milestone payment			$ 10,000
SciClone [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial payment		$ 10,000
Milestone payment		$ 50,500
Co-promotion and license income					100	$ 7,800
SymBio Pharmaceuticals Ltd [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial payment	$ 10,000
Milestone payment	$ 20,900
Co-promotion and license income					$ 600