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Collaboration agreement, milestone payments received.

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Collaboration agreements, additional remaining potential milestones payments receivable not included in transaction price.

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Contract with customer asset reclassified to receivable cash received.

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Deferred revenue, expected timing of recognition, month and year.

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License fees and other expenses.

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Variable consideration achieved and used in the transaction price.

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Number of performance obligations.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Cash received from collaborators during the current period.

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Cash received from licensees for license fees during the current period.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Collaboration Agreements - Additional Information (Details)	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2018 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2009 USD ($)	Sep. 30, 2018 USD ($) $ / shares	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2018 USD ($) PerformanceObligation $ / shares	Sep. 30, 2017 USD ($) $ / shares	Dec. 31, 2012 USD ($)	Dec. 31, 2010 USD ($)	Jan. 01, 2018 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				$ 5,175,000	$ 12,557,000	$ 45,137,000	$ 38,094,000
Net loss				$ (30,835,000)	$ (12,308,000)	$ (54,963,000)	$ (30,993,000)
Earnings per share, basic and diluted \| $ / shares				$ (1.07)	$ (0.50)	$ (2.03)	$ (1.34)
AbbVie \| License Agreement Terms
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue						$ 0
AbbVie \| Collaborative Arrangement \| Up-front Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Up-front collaboration payment received		$ 400,000,000
Number of performance obligations \| PerformanceObligation						3
Collaboration revenue				$ 6,717,000		$ 19,931,000
Deferred revenue				218,361,000		$ 218,361,000				$ 238,292,000
Deferred revenue, expected timing of recognition						2026-12
KHK Agreement \| License Agreement Terms
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of performance obligations \| PerformanceObligation						3
Deferred revenue				15,259,000		$ 15,259,000
Cash received						30,000,000
KHK Agreement \| License Agreement Terms \| Topic 606 \| Difference between Revenue Guidance in Effect before and after Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net loss				$ (3,337,000)		$ (7,626,000)
Earnings per share, basic and diluted \| $ / shares				$ (0.12)		$ (0.28)
KHK Agreement \| Up-front Payment Arrangement \| License Agreement Terms
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee received			$ 35,000,000
KHK Agreement \| Up-front Payment Arrangement \| License Agreement Terms \| Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee received			35,000,000
KHK Agreement \| Regulatory Development Milestone \| License Agreement Terms
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				$ (2,951,000)		$ 23,521,000
Collaboration revenue, milestone payments received						45,000,000		$ 45,000,000	$ 45,000,000
Collaboration revenue, potential milestone payments				52,000,000		52,000,000
Regulatory milestone variable consideration achieved and is used in the transaction price						30,000,000
Cumulative catch-up adjustment to collaboration revenue						21,881,000
Remainder of transaction price to be recognized as performance obligation				8,119,000		8,119,000
License fees and other expenses						3,600,000
KHK Agreement \| Regulatory Development Milestone \| License Agreement Terms \| Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue, milestone payments received	$ 30,000,000		$ 15,000,000
Collaboration agreements, additional remaining potential milestones not included in transaction price				52,000,000		52,000,000
KHK Agreement \| Commercial Milestones \| License Agreement Terms
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue, potential milestone payments				140,000,000		140,000,000
KHK Agreement \| Commercial Milestones \| License Agreement Terms \| Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration agreements, additional remaining potential milestones not included in transaction price				$ 140,000,000		$ 140,000,000