Collaborative Arrangements and Licensing Agreements, Strategic Partnerships - AstraZeneca (Details) $ in Thousands	1 Months Ended			3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) AccountingUnit Drug Program	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue earned				$ 160,349	$ 110,927	$ 38,470	$ 36,874	$ 51,571	$ 49,121	$ 120,428	$ 62,583	$ 346,620	$ 283,703	$ 214,161
Collaboration Agreements with AstraZeneca [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Deferred revenue	$ 51,500			51,500				$ 63,300				51,500	63,300
Revenue earned												$ 64,900	$ 6,400	$ 27,700
Collaboration Agreements with AstraZeneca [Member] | Revenue [Member] | Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage												19.00%	2.00%	13.00%
Cardiometabolic and Renal Diseases Partnership [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront payment received		$ 65,000
Number of units of accounting | AccountingUnit												1
Minimum potential amount of payments receivable for license fees and substantive milestones	4,000,000			4,000,000								$ 4,000,000
Maximum amount of payments receivable for development milestones	1,100,000			1,100,000								1,100,000
Maximum amount of payments receivable for regulatory milestones	2,900,000			2,900,000								2,900,000
Milestone payment earned	25,000
Next prospective milestone	10,000			10,000								10,000
Oncology Partnership [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Minimum potential amount of payments receivable for license fees and substantive milestones	750,000			750,000								750,000
Maximum amount of payments receivable for development milestones	226,000			226,000								226,000
Maximum amount of payments receivable for regulatory milestones	485,000			485,000								485,000
Milestone payment earned	15,000		$ 11,500
Next prospective milestone	17,500			17,500								$ 17,500
Number of drugs that can be licensed under option in collaboration agreement | Drug												3
Number of anti-cancer research programs covered by collaboration agreement | Program												3
Cumulative upfront fees received	31,000			31,000								$ 31,000
Upfront fee amortized into revenue	11,900			11,900								11,900
Deferred revenue	7,600			7,600								7,600
Milestone payment to be earned	5,000			5,000								5,000
Cumulative payments received	76,000			$ 76,000								$ 76,000
License fee earned	$ 13,000