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Collaboration Agreements, License Agreement and Revenues - Accounting for the Astellas Agreements - Additional Information 2 (Detail) - Astellas Agreement [Member]	12 Months Ended
	Dec. 31, 2021 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Co-development services related to CKD continued over development period	2021-08
Minimum [Member] | Measurement Input Discount Rate [Member] | Discounted Cash Flow [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Discount rate applied	17.5
Maximum [Member] | Measurement Input Discount Rate [Member] | Discounted Cash Flow [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Discount rate applied	20.0
Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-contingent upfront payments received	$ 40,100,000
Variable consideration related to payments for milestones considered probable of being achieved	65,000,000.0
Variable consideration related to co-development billings	11,900,000
Provision for co-development services	0
Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-contingent upfront payments received	320,000,000.0
Variable consideration related to payments for milestones considered probable of being achieved	340,000,000.0
Variable consideration related to co-development billings	$ 219,900,000

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- Definition

Co-development services related to CKD continued over development period.

+ References

No definition available.

+ Details

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- Definition

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+ References

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- Definition

Provision for co-development services.

+ References

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- Definition

Variable consideration payment received related to co-development billings.

+ References

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- Definition

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- Definition

Value of input used to measure alternative investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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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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