Collaborations - Additional Information (Detail) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Deliverables	Jun. 30, 2016 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and milestone fee revenue			$ 530
Collaborative revenue			313
Clinical compound revenue		$ 79	68	$ 86
Maruishi Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and milestone fee revenue			$ 530
Number of deliverables for revenue recognized \| Deliverables			2
Collaborative revenue			$ 313
Sub-license fee			843
Clinical compound revenue	$ 0	79	68	86
Cost of clinical compound	$ 0	$ 72	$ 61	$ 78

Amount of revenue recognized from the sale of clinical compound to Maruishi.

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- Definition

Cost of clinical compound sale related to research and development expense.

+ References

No definition available.

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- Definition

Number of items that the company is contractually required to provide to the licensee during the term of the license. Revenue recognized by the company is apportioned among the identified deliverables.

+ 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

Revenue earned during the period relating to consideration received from another party for the right to use, but not own, certain of the entity's intangible assets. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark. Licensing fees are generally, but not always, fixed as to amount and not dependent upon the revenue generated by the licensing party. An entity may receive licensing fees for licenses that also generate royalty payments to the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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- Definition

The amount of compensation earned (contract income) under a research and development arrangement accounted for as a contract to perform research and development for others.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6420387&loc=d3e23199-108380

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6420387&loc=d3e23221-108380

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- Definition

The amount of consideration recognized during the period for the milestone or milestones.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 28
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=68058744&loc=SL6892177-166501

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