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Related Parties - Additional Information (Detail) - Mosaic - USD ($) $ in Millions		12 Months Ended
	May 08, 2020	Dec. 31, 2020	Dec. 31, 2019	Jan. 10, 2020
Related Party Transaction [Line Items]
Expenses related to collaboration	$ 0.8
Maximum
Related Party Transaction [Line Items]
Milestone Payment Related To Regulatory And Clinical Development Events	$ 4.0
Research and Development Expense
Related Party Transaction [Line Items]
Other Research and Development Expense		$ 0.8
Intravitreal Anti-Complement Factor 3
Related Party Transaction [Line Items]
Payment related to collaboration		3.0
Collaboration Agreement
Related Party Transaction [Line Items]
Expenses related to collaboration		1.6
Collaboration Agreement | Intravitreal Anti-Complement Factor 3
Related Party Transaction [Line Items]
Expenses related to collaboration		$ 1.3	$ 1.1
Biogen Collaboration | Intravitreal Anti-Complement Factor 3
Related Party Transaction [Line Items]
Upfront license fee received from collaboration agreement				$ 15.0

X

- Definition

Milestone payment .

+ References

No definition available.

+ Details

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- Definition

Sublicense fee entitled to pay.

+ References

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+ Details

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- Definition

Total transaction expenses related to collaboration.

+ References

No definition available.

+ Details

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- Definition

Upfront fee reveived from license and collaboration agreement.

+ References

No definition available.

+ Details

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X

- 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.

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- Details

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