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Significant Accounting Policies - Additional Information (Detail) $ in Millions		9 Months Ended
	Aug. 29, 2025 USD ($)	Sep. 30, 2025 Segment shares	Jun. 16, 2025 shares	Feb. 20, 2025	Dec. 31, 2024 shares
Accounting Policy [Line Items]
Common Stock, Shares, Outstanding | shares		4,045,000			4,037,000
Common stock, shares authorized | shares		225,000,000	4,000,000		225,000,000
Number of reportable segment | Segment		1
Reverse Stock Split [Member]
Accounting Policy [Line Items]
Reverse stock split		1-for-25
Common Stock, Shares, Outstanding | shares			101,100,000
FibroGen International [Member]
Accounting Policy [Line Items]
Discontinued operations name		FibroGen International
Beijing Falikang Pharmaceutical Co Ltd | Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] | AstraZenecaAB [Member]
Accounting Policy [Line Items]
Percentage of outstanding shares acquired				51.10%
Share Purchase Agreement [Member]
Accounting Policy [Line Items]
Discontinued operation consideration	$ 220.4
Share Purchase Agreement [Member] | FibroGen International [Member]
Accounting Policy [Line Items]
Discontinued operation consideration	220.4
Discontinued operation consideration in cash	85.0
Cash received for sale of discontinued operation	210.4
Outstanding interest and related premium and fees	80.9
Purchase price in cash	85.0
Share Purchase Agreement [Member] | FibroGen International [Member] | CHINA
Accounting Policy [Line Items]
Discontinued operation consideration	220.4
Discontinued operation consideration in cash	85.0
Purchase price in cash	85.0
Share Purchase Agreement [Member] | Net Cash Held in China [Member]
Accounting Policy [Line Items]
Discontinued operation consideration in cash	135.4
Purchase price in cash	135.4
Share Purchase Agreement [Member] | Net Cash Held in China [Member] | CHINA
Accounting Policy [Line Items]
Discontinued operation consideration in cash	135.4
Purchase price in cash	$ 135.4

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