Reduction of other expenses.

No definition available.

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Namespace Prefix:	fgen_
Data Type:	xbrli:monetaryItemType
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- Definition

Amount of increase (decrease) in accrued expenses, and obligations classified as other.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) in current assets classified as other.

+ References

+ Details

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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Subsequent Event - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Jun. 30, 2021
Subsequent Event [Line Items]
Reduction of accrued and other current liabilities		$ 61,005	$ 27,745
Intellectual Property Rights [Member]
Subsequent Event [Line Items]
Reduction of accrued and other current liabilities	$ 8,200
Reduction of other assets	2,300
Reduction of other expenses	$ 6,000