Collaboration Agreements (Details) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 16, 2014	Feb. 28, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-promotion and license income			$ 638,000	$ 7,326,000	$ 9,026,000	$ 13,346,000
SciClone [Member] | Collaborative Arrangement, Co-promotion [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative Agreement, Milestone Payment Received	$ 50,500,000
Co-promotion and license income					$ 8,000,000
Alnylam Pharmaceuticals, Inc. [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial payment		$ 25,000,000
Collaborative Arrangement, Milestone Payment		10,000,000
Maximum payment for success-based development and commercialization milestones		$ 170,000,000