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Revenue - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Oct. 31, 2016 USD ($) Employee	Mar. 31, 2017 USD ($)
Revenue Recognition, Milestone Method [Line Items]
Revenue		$ 1,192,000
Novartis Institutes for BioMedical Research, Inc [Member] | Collaboration Agreement [Member]
Revenue Recognition, Milestone Method [Line Items]
Initial research term of agreement	2 years
Research term of the agreement, description		The initial research term by up to two additional one-year periods
Upfront payment received	$ 5,000,000
Number of full-time employees engaged in research activities under the collaboration | Employee	5
Novartis Institutes for BioMedical Research, Inc [Member] | Collaboration Agreement [Member] | Upfront Fee [Member]
Revenue Recognition, Milestone Method [Line Items]
Revenue		$ 625,000
Novartis Institutes for BioMedical Research, Inc [Member] | Collaboration Agreement [Member] | Funding for Activities Performed [Member]
Revenue Recognition, Milestone Method [Line Items]
Revenue		$ 567,000

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Describes the terms of significant agreements under research and development arrangements accounted for as a contract to perform research and development for others (including royalty arrangements, purchase provisions, license agreements, and commitments to provide additional funding), aggregated by similar arrangements or individually if necessary to understand the effects on the financial statements.

+ 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 (a)
-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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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ 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)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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