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Represents the percentage of associated future global development costs from the initiation of a Phase IIb trial provided the entity elects to co-develop any compounds and/or indications.

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Amount of expenses incurred but not yet paid nor invoiced, and liabilities classified as other.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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License agreements - Lilly (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended			12 Months Ended					112 Months Ended
	Mar. 31, 2016	Jul. 31, 2010	Dec. 31, 2009	Jun. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2012	Dec. 31, 2010	Mar. 31, 2019
License agreements
Research and Development Expense					$ 270,545	$ 303,103
Revenues					497,857	382,282
Product royalty revenues
License agreements
Revenues					61,608	47,716
Eli Lilly
License agreements
Upfront payment received under license agreement			$ 90,000
Product royalties in accounts receivable					$ 16,200		$ 14,000					$ 16,200
Eli Lilly \| Maximum
License agreements
Associated future global development costs from the initiation of a Phase IIb trial, if elected to co-develop (as a percentage)	20.00%
Eli Lilly \| Phase IIB
License agreements
Funding of future development costs (as a percent)		30.00%		30.00%	30.00%
Research and Development Expense					$ 0	12,500
Accrued and other liabilities					0		23,100					0
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							20,000	$ 30,000				149,000
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 III
License agreements
Amount recognized and received for the achievement of a predefined milestone										$ 50,000
Eli Lilly \| Development Milestones \| Phase IIA
License agreements
Amount recognized and received for the achievement of a predefined milestone											$ 30,000
Eli Lilly \| Development Milestones \| Phase IIB
License agreements
Amount recognized and received for the achievement of a predefined milestone											$ 19,000
Eli Lilly \| Regulatory Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone							$ 100,000					$ 235,000
Eli Lilly \| Regulatory Milestones \| JAPAN
License agreements
Amount recognized and received for the achievement of a predefined milestone								15,000
Eli Lilly \| Regulatory Milestones \| U.S.
License agreements
Amount recognized and received for the achievement of a predefined milestone									$ 35,000
Eli Lilly \| Regulatory Milestones \| Europe
License agreements
Amount recognized and received for the achievement of a predefined milestone								$ 65,000	$ 20,000
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
Eli Lilly \| Development and Commercialization Milestones
License agreements
Revenues					0	0
Eli Lilly \| GVHD
License agreements
Upfront payment under license agreement	$ 35,000
Additional milestone payments under the license agreement	$ 40,000
Eli Lilly \| Product royalty revenues
License agreements
Revenues					$ 16,000	$ 6,400