Adjustment due to adoption of new accounting principle in period of adoption.

No definition available.

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- Definition

Milestone payment .

+ References

No definition available.

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- Definition

Upfront fee reveived from license and collaboration agreement.

+ References

No definition available.

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- Definition

Amount of other research and development expense.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 10
-Section 50
-Paragraph 1
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- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
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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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Related Parties - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	May 08, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 10, 2020
Mosaic
Related Party Transaction [Line Items]
Expenses related to collaboration	$ 0.8
Payment related to collaboration				$ 3.0
Mosaic \| Maximum
Related Party Transaction [Line Items]
Milestone payments , clinical development events				4.0
Mosaic \| Research and development
Related Party Transaction [Line Items]
Cash research and development expense				0.8
Mosaic \| Collaboration Agreement \| Intravitreal Anti-Complement Factor 3
Related Party Transaction [Line Items]
Expenses related to collaboration		$ 0.2	$ 0.3	$ 1.5	$ 0.8
Biogen \| License and Collaboration Agreement (the “Biogen Agreement”)
Related Party Transaction [Line Items]
Upfront license fee received from collaboration agreement						$ 15.0