Research collaboration agreement with Allergan (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jul. 24, 2015 USD ($) Option
Research collaboration agreement with Allergan
Research and development	$ 11,761	$ 11,950	$ 33,732	$ 37,860
Non-Refundable Milestone Payment		1,000		1,000
RCA
Research collaboration agreement with Allergan
Payment of option exercise fee					$ 1,000
Number of options to acquire molecules \| Option					3
capitalized contract costs	0		0
Research and development	$ 1,900	$ 1,900	$ 5,500	$ 5,800
Development activities reimbursement percentage	50.00%	50.00%	50.00%	50.00%
Development activities expenses reimbursed	$ 900	$ 900	$ 2,800	$ 2,900
Remaining performance obligation		$ 0		$ 0

Amount of expenses paid towards non-refundable milestone payment.

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The number of options to acquire molecules from a pool of eligible compounds that would result in the termination of the research collaboration agreement.

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The amount that was reimbursed under the research collaboration agreement.

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The percentage of research and development expenses that are reimbursable under the research collaboration agreement.

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Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

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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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