XML 70 R61.htm IDEA: XBRL DOCUMENT v3.25.1

Equity method investment - Variable Interest Entity - Additional Information (Detail)	Feb. 20, 2025	Dec. 31, 2024
Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] | Beijing Falikang Pharmaceutical Co Ltd | AstraZenecaAB [Member]
Acquisition And Variable Interest Entity [Line Items]
Percentage of outstanding shares acquired	51.10%	51.10%

X

- Definition

Acquisition and variable interest entity line items.

+ References

No definition available.

+ Details

Name:	fgen_AcquisitionAndVariableInterestEntityLineItems
Namespace Prefix:	fgen_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_BusinessAcquisitionAxis=fgen_BeijingKangdaYongfuPharmaceuticalCoLTDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis=fgen_BeijingFalikangPharmaceuticalCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=fgen_AstraZenecaABMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: