License and Collaboration Agreements - Changes in Deferred Revenue Balance from Collaboration Agreements (Detail) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jan. 01, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue, Beginning balance	$ 37,970
Additions to deferred revenue	4,000
Recognition of previously unearned revenue	(8,249)
Deferred revenue, Ending balance	$ 31,768
ASC 606 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transition adjustment related to adoption of ASC 606		$ (1,953)

Increase in contract with customer liability for consideration.

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- Definition

New accounting pronouncement or change in accounting principle, cumulative effect of change on deferred revenue.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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