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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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License agreements (Details) $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended					70 Months Ended	71 Months Ended
License agreements (Details) $ in Thousands	Jul. 31, 2010	Dec. 31, 2009 USD ($) item	Nov. 30, 2009 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)
License agreements
Contract revenues				$ 8,214	$ 88,214	$ 39,643	$ 101,643
Product royalty revenues				18,138	12,093	51,175	34,259
Novartis
License agreements
Upfront and immediate milestone payment to be received under license agreement			$ 210,000
Product royalties in accounts receivable				18,200		18,200		$ 14,800					$ 18,200	$ 18,200
Reimbursable costs recorded as deferred revenue		$ 10,900
Reimbursable costs included in accounts receivable				300		300		300					300	300
Research and development expenses reimbursed				300	500	1,300	2,700
Contract revenues				5,000	85,000	30,000	92,000
Novartis \| UNITED STATES
License agreements
Royalties payable				7,400		15,500
Novartis \| Pre-specified Events \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement			1,200,000
Novartis \| Development Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone														102,000
Novartis \| Development Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement			174,000
Novartis \| Regulatory Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone														$ 160,000
Novartis \| Regulatory Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement			495,000
Novartis \| Commercialization Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement			$ 500,000
Novartis \| JAKAFI
License agreements
Product royalty revenues				18,100	12,100	51,200	34,300
Novartis \| JAKAFI \| Development Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone						5,000		7,000	$ 25,000		$ 15,000
Novartis \| JAKAFI \| Regulatory Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone											$ 10,000
Novartis \| JAKAFI \| Regulatory Milestones \| Europe
License agreements
Amount recognized and received for the achievement of a predefined milestone						25,000		60,000		$ 40,000
Novartis \| JAKAFI \| Regulatory Milestones \| JAPAN
License agreements
Amount recognized and received for the achievement of a predefined milestone								$ 25,000
Eli Lilly
License agreements
Number of deliverables under license agreement \| item		2
Upfront payment received under license agreement		$ 90,000
Research and development expenses reimbursed				6,400	11,500	28,300	38,300
Contract revenues				$ 3,200	$ 3,200	$ 9,600	$ 9,600
Associated future global development costs from the initiation of a Phase IIb trial, if elected to co-develop, percentage	30.00%	30.00%		30.00%	30.00%	30.00%	30.00%
Eli Lilly \| Maximum
License agreements
Range of royalty payments on future global net sales (as a percent)						20.00%
Eli Lilly \| Pre-specified Events \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement		$ 665,000
Eli Lilly \| Development Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone													$ 99,000
Eli Lilly \| Development Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement		150,000
Eli Lilly \| Development Milestones \| Phase Three
License agreements
Amount recognized and received for the achievement of a predefined milestone										$ 50,000
Eli Lilly \| Development Milestones \| Phase Two A
License agreements
Amount recognized and received for the achievement of a predefined milestone												$ 30,000
Eli Lilly \| Development Milestones \| Phase Two B
License agreements
Amount recognized and received for the achievement of a predefined milestone												$ 19,000
Eli Lilly \| Regulatory Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement		365,000
Eli Lilly \| Commercialization Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement		$ 150,000