0000950170-25-106549 | 10-Q | XBRL Viewer

Collaboration Agreements, License Agreement and Revenues (Tables)

6 Months Ended

Jun. 30, 2025

Roll-forward of Related Contract Liabilities

The following table includes a roll-forward of the above-mentioned deferred revenues that are considered as contract liabilities related to drug product (in thousands):


	Balance at December 31, 2024			Recognized as Revenue		Reclassified to Accrued Liability / Accounts Payable		Balance at June 30, 2025
Drug product revenue - deferred revenue:
Astellas Europe Agreement	$	(9,901	)	$	1,986	$	1,327	$	(6,588	)

AstraZeneca Agreements [Member]

Roll-forward of Related Contract Liabilities

The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands):


	Balance at December 31, 2024			Additions			Recognized as Revenue (Discontinued Operations)		Currency Translation and Other			Balance at June 30, 2025
AstraZeneca China performance obligation - deferred revenue	$	(132,097	)	$	(63,509	)	$	53,308	$	(649	)	$	(142,947	)

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2025

Accounting Policies [Abstract]

Discontinued Operations

On February 20, 2025, the Company entered into the Share Purchase Agreement with AstraZeneca Treasury Limited pursuant to which FibroGen and its subsidiary FibroGen China Anemia Holdings, Ltd. agreed to sell all of the issued and outstanding equity interests of FibroGen International to AstraZeneca Treasury Limited for an aggregate purchase price comprised of $85 million in cash for the enterprise value of FibroGen International, plus an additional cash amount equal to the net cash held in China by FibroGen International and its subsidiaries as of the closing. This sale includes all of FibroGen’s roxadustat assets in China, including FibroGen International’s subsidiary FibroGen Beijing and its 51.1% interest in Falikang. The transaction is expected to close in the third quarter of 2025, and is subject to customary closing conditions and closing deliverables, including receipt of regulatory approval from the China SAMR. The Company analyzed the quantitative and qualitative factors and concluded that the sale of FibroGen International represents a strategic shift in FibroGen’s business and qualified as a discontinued operation. As a result, the Company determined that FibroGen International met the “held for sale” criteria and the “discontinued operations” criteria in accordance with Financial Accounting Standard Board (“FASB”) Accounting Standards Codification (“ASC”) 205, Presentation of Financial Statements, as of June 30, 2025 and December 31, 2024. Accordingly, the condensed consolidated balance sheets and the condensed consolidated statements of operations, and the notes to the condensed consolidated financial statements were recasted for all periods presented to reflect the discontinuation of FibroGen International in accordance with ASC 205. The operating results related to FibroGen International are classified as discontinued operations, and have been reflected as discontinued operations in the condensed consolidated statements of operations, while the related assets and liabilities were classified within the condensed consolidated balance sheets as held for sale for all periods presented. See Note 2, Discontinued Operations, for related disclosures. Unless otherwise noted, discussion in the notes to these consolidated financial statements, relates to solely to the Company’s continuing operations.

Use of Estimates

The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions include valuation and recognition of revenue and deferred revenue, specifically, estimates in variable consideration for drug product sales, and estimates in transaction price per unit for the China performance obligation. On an ongoing basis, management reviews these estimates and assumptions. Changes in facts and circumstances may alter such estimates and actual results could differ from those estimates. In the Company’s opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of its financial position, results of operations and cash flows for the interim periods presented.

Net Loss per Share

Net Income (Loss) per Share

Potential common shares that would have the effect of increasing diluted earnings per share are considered to be anti-dilutive and as such, these shares are not included in the calculation of diluted earnings per share. The Company reported a loss from continuing operations for each of the three and six months ended June 30, 2025 and 2024. Therefore, dilutive common shares are not assumed to have been issued since their effect is anti-dilutive for these periods.

Diluted weighted average shares excluded the following potential common shares related to stock options, service-based restricted stock units (“RSUs”), performance-based RSUs (“PRSUs”), total shareholder return (“TSR”) awards and shares to be purchased under the 2014 Employee Stock Purchase Plan (“ESPP”) for the periods presented as they were anti-dilutive (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2025		2024		2025		2024
Employee stock options		490		603		500		551
RSUs, PRSUs and TSR awards		36		156		42		157
ESPP		—		18		—		20
		526		777		542		728

Fair Value Measurements

6 Months Ended

Jun. 30, 2025

Fair Value Disclosures [Abstract]

Fair Value Measurements

5. Fair Value Measurements

The fair values of the Company’s financial assets that are measured on a recurring basis are as follows (in thousands):


	June 30, 2025
	Level 1		Level 2		Level 3		Total
Money market funds	$	5,296	$	—	$	—	$	5,296
Commercial paper		—		12,082		—		12,082
U.S. government bonds		3,190		1,295		—		4,485
Total	$	8,486	$	13,377	$	—	$	21,863

	December 31, 2024
	Level 1		Level 2		Level 3		Total
Money market funds	$	28,241	$	—	$	—	$	28,241
Commercial paper		—		14,269		—		14,269
U.S. government bonds		2,987		2,981		—		5,968
Total	$	31,228	$	17,250	$	—	$	48,478

The Company’s Level 2 investments are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar investments, issuer credit spreads, benchmark investments, prepayment/default projections based on historical data and other observable inputs. During the three and six months ended June 30, 2025, a total of $1.3 million and $7.8 million, respectively, of U.S. treasury notes and bills were transferred from Level 1 to Level 2 as such instruments were changed to off-the-run when they were issued before the most recent issue and were still outstanding at measurement day.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

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+ Details

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Schedule of Investments [Abstract]
Total inventories	$ 3,863	$ 3,155

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	1 Months Ended	2 Months Ended	32 Months Ended
	May 31, 2025 USD ($)	May 31, 2021 PutativeClassAction	Apr. 03, 2024 ShareholderDerivative	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Oct. 17, 2023 USD ($)
Commitments And Contingencies [Line Items]
Number of complaints filed		5	7
Litigation settlement amount					$ 28,500	$ 28,500
Civil penalty payment	$ 1,250
General Purchases And Other Programs [Member]
Commitments And Contingencies [Line Items]
Recorded unconditional purchase obligation				$ 3,100
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Recorded unconditional purchase obligation				$ 500

Discontinued Operations - Schedule of Financial Results of Discontinued Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Interest and other, net
Income from discontinued operations, net of tax	$ 6,080	$ 31,551	$ 27,485	$ 47,664
FibroGen International [Member]
Revenue:
Product revenue, net	19,655	49,643	59,472	80,181
Operating costs and expenses:
Cost of goods sold	4,290	5,038	9,692	9,448
Research and development	542	1,746	1,301	3,650
Selling, general and administrative	6,074	7,370	13,538	13,475
Total operating costs and expenses	10,906	14,154	24,531	26,573
Income from operations	8,749	35,489	34,941	53,608
Interest and other, net
Interest expense	(2,964)	(2,915)	(5,915)	(5,819)
Interest income and other income (expenses), net	(1,367)	(2,181)	(2,649)	(1,846)
Total interest and other, net	(4,331)	(5,096)	(8,564)	(7,665)
Income before income taxes	4,418	30,393	26,377	45,943
Provision for income taxes	0	19	0	45
Investment income in unconsolidated variable interest entity	1,662	1,177	1,108	1,766
Income from discontinued operations, net of tax	$ 6,080	$ 31,551	$ 27,485	$ 47,664

Senior Secured Term Loan Facilities - Summary of Senior Secured Term Loan Facilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Representing:
Senior secured term loan facilities, current	$ (73,733)	$ 0
Senior secured term loan facilities, non-current	0	73,092
Senior Secured Term Loan Facilities [Member]
Debt Instrument [Line Items]
Principal of senior secured term loan facilities	75,000	75,000
Less: Unamortized issuance costs and transaction costs	(1,267)	(1,908)
Senior secured term loan facilities, ending balance	73,733	73,092
Representing:
Senior secured term loan facilities, current	(73,733)	0
Senior secured term loan facilities, non-current	$ 0	$ 73,092

- 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

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References + Details

Collaboration Agreements, License Agreement and Revenues - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue (Detail) - AstraZeneca Agreements [Member] - U.S./RoW and China [Member] $ in Millions	Jun. 30, 2025 USD ($)
License [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	$ 344.5
Product [Member]
Disaggregation of Revenue [Line Items]
Cumulative Revenue	408.1
Co-development, information sharing & committee services [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	625.5
China performance obligation [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	$ 551.1

- 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 + Details

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Jul. 31, 2024	Jun. 30, 2025	Jun. 30, 2025	Dec. 31, 2024
Schedule of Available-for-sale Securities [Line Items]
API and bulk drug product price true-up		$ 12,444	$ 12,444	$ 13,071
Accrued litigation settlement				28,500
Litigation settlement receivable		0	0	$ 28,500
Restructuring plan, expected reduction to workforce, percentage	75.00%
Cash payments for restructuring		800	2,400
Accrued restructuring charges		$ 1,700	$ 1,700

- 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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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

+ Details

Liability Related to Sale of Future Revenues - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		$ 1,348,000	$ 998,000	$ 4,088,000	$ 26,363,000
Interest expense related to sale of future revenues				4,134,000
Interest paid				450,000	5,700,000
NovaQuest Capital Management [Member] \| Revenue Interest Financing Agreement [Member] \| Minimum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Prepayment amount of 2024 to 2030	$ 80,000,000
NovaQuest Capital Management [Member] \| Revenue Interest Financing Agreement [Member] \| Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Prepayment amount of 2024 to 2030	125,000,000
NovaQuest Capital Management [Member] \| Payment Period One [Member] \| Revenue Interest Financing Agreement [Member] \| Minimum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue interest payment	62,500,000
NovaQuest Capital Management [Member] \| Payment Cap Date on or before December 31, 2028 [Member] \| Revenue Interest Financing Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum payment cap amount	100,000,000
NovaQuest Capital Management [Member] \| Payment Cap Date on or after January 1, 2029 [Member] \| Revenue Interest Financing Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum payment cap amount	112,500,000
NovaQuest Capital Management [Member] \| Payment Cap Date after January 1, 2030 [Member] \| Revenue Interest Financing Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum payment cap amount	125,000,000
NovaQuest Capital Management [Member] \| Payment Period Two [Member] \| Revenue Interest Financing Agreement [Member] \| Minimum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue interest payment	125,000,000
Product [Member] \| NovaQuest Capital Management [Member] \| Revenue Interest Financing Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue interest payment	10,000,000
Other Revenue - Contract Manufacturing [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		133,000	269,000	277,000	1,147,000
Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future revenue granted	$ 50,000,000
Astellas Agreement [Member] \| Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue payment cap amount		125,000,000		125,000,000
Development Revenue [Member] \| Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		100,000	300,000	300,000	600,000
Drug Product Revenue [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		1,215,000	729,000	3,811,000	25,216,000
Drug Product Revenue [Member] \| Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		1,200,000	700,000	3,800,000	(500,000)
Non-cash interest expense related to drug product revenue		$ 2,000,000	$ 1,700,000	$ 4,100,000	$ 3,700,000

Discontinued Operations - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Feb. 20, 2025	Dec. 31, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable from related parties	$ 136		$ 136			$ 481
Falikang [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of outstanding shares owned			51.10%
Investment income (loss)	1,700	$ 1,200	$ 1,100	$ 1,800
Equity method investments	8,100		8,100			6,900
Accounts receivable from related parties	19,100		19,100			$ 13,900
Falikang [Member] \| Collaborative Arrangement [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	16,400	$ 46,000	$ 53,300	$ 73,100
Decrease in revenue	$ 12,100
FibroGen International [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Description of discontinued operations			On February 20, 2025, the Company entered into the Share Purchase Agreement with AstraZeneca Treasury Limited, pursuant to which FibroGen and its subsidiary FibroGen China Anemia Holdings, Ltd. agreed to sell all of the issued and outstanding equity interests of FibroGen International to AstraZeneca Treasury Limited for an aggregate purchase price comprised of $85 million in cash for the enterprise value of FibroGen International, plus an additional cash amount equal to the net cash held in China by FibroGen International and its subsidiaries as of the closing. This sale includes all of our roxadustat assets in China, including FibroGen International’s subsidiary FibroGen Beijing and its 51.1% interest in Falikang. The transaction is expected to close in the third quarter of 2025, and is subject to customary closing conditions and closing deliverables, including receipt of regulatory approval from the China SAMR. The Company analyzed the quantitative and qualitative factors and concluded that the sale of FibroGen International represents a strategic shift in FibroGen’s business and qualified as a discontinued operation. As a result, Company determined that FibroGen International met the “held for sale” criteria and the “discontinued operations” criteria in accordance with FASB ASC 205, Presentation of Financial Statements, as of June 30, 2025 and December 31, 2024. Accordingly, the operating results related to the FibroGen International are classified as discontinued operations, and have been reflected as discontinued operations in the condensed consolidated statements of operations, while the related assets and liabilities were classified within the condensed consolidated balance sheets as held for sale for all periods presented.
Discontinued operations name			FibroGen International
Purchase price in cash					$ 85,000

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	$ 21,863	$ 48,478
Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	5,296	28,241
Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,082	14,269
U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	4,485	5,968
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	8,486	31,228
Level 1 [Member] \| Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	5,296	28,241
Level 1 [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Level 1 [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	3,190	2,987
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	13,377	17,250
Level 2 [Member] \| Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	0	0
Level 2 [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,082	14,269
Level 2 [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	1,295	2,981
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Level 3 [Member] \| Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	0	0
Level 3 [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 0	$ 0

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Accrued Liabilities, Current [Abstract]
Preclinical and clinical trial accruals	$ 5,991	$ 6,327
API and bulk drug product price true-up	12,444	13,071
Litigation settlement	0	28,500
Payroll and related accruals	4,998	4,640
Accrued restructuring charge	1,715	4,572
Professional services	6,204	2,049
Current portion of liability related to sale of future revenues	1,702	460
Other	2,862	2,416
Total accrued and other current liabilities	$ 35,916	$ 62,035

Significant Accounting Policies - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2025 USD ($) Segment shares	Jun. 16, 2025 shares	Feb. 20, 2025 USD ($)	Dec. 31, 2024 shares
Accounting Policy [Line Items]
Common Stock, Shares, Outstanding \| shares	4,044,000			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]
Purchase price in cash \| $			$ 85,000
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%		51.10%
Minimum [Member]
Accounting Policy [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts \| $	$ 18,750
Debt Financing Agreement [Member] \| Minimum [Member]
Accounting Policy [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts \| $	$ 22,500

Discontinued Operations (Tables)

6 Months Ended

Jun. 30, 2025

Discontinued Operations and Disposal Groups [Abstract]

Schedule of Financial Results, Carrying Value of Assets and Liabilities and Significant Non-Cash Items and Capital Expenditures of Discontinued Operations

The financial results of the discontinued operations with respect to FibroGen International reflected in the condensed consolidated statements of operations for the three and six months ended June 30, 2025 and 2024 were as follows (in thousands):


	Three Months Ended June 30,						Six Months Ended June 30,
	2025			2024			2025			2024
Revenue:
Product revenue, net	$	19,655			49,643		$	59,472		$	80,181
Operating costs and expenses:
Cost of goods sold		4,290			5,038			9,692			9,448
Research and development		542			1,746			1,301			3,650
Selling, general and administrative		6,074			7,370			13,538			13,475
Total operating costs and expenses		10,906			14,154			24,531			26,573
Income from operations		8,749			35,489			34,941			53,608
Interest and other, net
Interest expense		(2,964	)		(2,915	)		(5,915	)		(5,819	)
Interest income and other income (expenses), net		(1,367	)		(2,181	)		(2,649	)		(1,846	)
Total interest and other, net		(4,331	)		(5,096	)		(8,564	)		(7,665	)
Income before income taxes		4,418			30,393			26,377			45,943
Provision for income taxes		—			19			—			45
Investment income in unconsolidated variable interest entity		1,662			1,177			1,108			1,766
Income from discontinued operations, net of tax	$	6,080		$	31,551		$	27,485		$	47,664

The carrying value of the assets and liabilities of the discontinued operations with respect to FibroGen International on the condensed consolidated balance sheets as of June 30, 2025 and December 31, 2024 were as follows (in thousands):


	June 30, 2025		December 31, 2024
Assets
Cash and cash equivalents	$	96,474	$	51,696
Accounts receivable, net		22,143		18,443
Inventories		10,871		15,547
Prepaid expenses and other current assets		3,162		25,163
Total current assets held for sale		132,650		110,849

Property and equipment, net		4,670		7,041
Equity method investment in unconsolidated variable interest entity		8,115		6,864
Operating lease right-of-use assets		1,122		1,716
Other assets		987		990
Total long-term assets held for sale		14,894		16,611

Liabilities
Accounts payable	$	123	$	26,974
Accrued and other current liabilities		7,486		10,679
Operating lease liabilities, current		849		1,264
Total current liabilities held for sale		8,458		38,917

Operating lease liabilities, non-current		156		356
Total long-term liabilities held for sale		156		356

The significant non-cash items and capital expenditures for the discontinued operations with respect to FibroGen International included in the condensed consolidated statements of cash flows for the six months ended June 30, 2025 and 2024 were as follows (in thousands):


	Six Months Ended June 30,
	2025			2024
Depreciation	$	530		$	753
Investment loss (income) in unconsolidated variable interest entity		(1,108	)		(1,766	)
Impairment of property and equipment		2,062			—
Stock-based compensation	$	943		$	884

- Definition

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-SubTopic 10
-Topic 360
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483475/205-20-45-11

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-3A

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-4A

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-4B

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5A

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5D
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5D

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-7

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3A

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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-URI https://asc.fasb.org/1943274/2147483499/205-20-50-1

Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-3

+ Details

Discontinued Operations - Schedule of Carrying Value of Assets and Liabilities of Discontinued Operations (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Assets
Total current assets held for sale	$ 132,650	$ 110,849
Total long-term assets held for sale	14,894	16,611
Liabilities
Total current liabilities held for sale	8,458	38,917
Total long-term liabilities held for sale	156	356
FibroGen International [Member]
Assets
Cash and cash equivalents	96,474	51,696
Accounts receivable, net	22,143	18,443
Inventories	10,871	15,547
Prepaid expenses and other current assets	3,162	25,163
Total current assets held for sale	132,650	110,849
Property and equipment, net	4,670	7,041
Equity method investment in unconsolidated variable interest entity	8,115	6,864
Operating lease right-of-use assets	1,122	1,716
Other assets	987	990
Total long-term assets held for sale	14,894	16,611
Liabilities
Accounts payable	123	26,974
Accrued and other current liabilities	7,486	10,679
Operating lease liabilities, current	849	1,264
Total current liabilities held for sale	8,458	38,917
Operating lease liabilities, non-current	156	356
Total long-term liabilities held for sale	$ 156	$ 356

Liability Related to Sale of Future Revenues - Schedule of Activities of Liability Related to Sale of Future Revenues (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Liability Related to Sale of Future Royalties [Abstract]
Liability related to sale of future revenues - beginning balance	$ 59,324
Interest paid	(450)	$ (5,700)
Interest expense recognized	4,134
Liability related to sale of future revenues - ending balance	63,008
Less: Current portion classified to accrued and other current liabilities	(1,702)
Liability related to sale of future revenues, non-current	$ 61,306

Discontinued Operations

6 Months Ended

Jun. 30, 2025

Discontinued Operations and Disposal Groups [Abstract]

Discontinued Operations

2. Discontinued Operations

On February 20, 2025, the Company entered into the Share Purchase Agreement with AstraZeneca Treasury Limited, pursuant to which FibroGen and its subsidiary FibroGen China Anemia Holdings, Ltd. agreed to sell all of the issued and outstanding equity interests of FibroGen International to AstraZeneca Treasury Limited for an aggregate purchase price comprised of $85 million in cash for the enterprise value of FibroGen International, plus an additional cash amount equal to the net cash held in China by FibroGen International and its subsidiaries as of the closing. This sale includes all of our roxadustat assets in China, including FibroGen International’s subsidiary FibroGen Beijing and its 51.1% interest in Falikang. The transaction is expected to close in the third quarter of 2025, and is subject to customary closing conditions and closing deliverables, including receipt of regulatory approval from the China SAMR. The Company analyzed the quantitative and qualitative factors and concluded that the sale of FibroGen International represents a strategic shift in FibroGen’s business and qualified as a discontinued operation. As a result, Company determined that FibroGen International met the “held for sale” criteria and the “discontinued operations” criteria in accordance with FASB ASC 205, Presentation of Financial Statements, as of June 30, 2025 and December 31, 2024. Accordingly, the operating results related to the FibroGen International are classified as discontinued operations, and have been reflected as discontinued operations in the condensed consolidated statements of operations, while the related assets and liabilities were classified within the condensed consolidated balance sheets as held for sale for all periods presented.


	Three Months Ended June 30,						Six Months Ended June 30,
	2025			2024			2025			2024
Revenue:
Product revenue, net	$	19,655			49,643		$	59,472		$	80,181
Operating costs and expenses:
Cost of goods sold		4,290			5,038			9,692			9,448
Research and development		542			1,746			1,301			3,650
Selling, general and administrative		6,074			7,370			13,538			13,475
Total operating costs and expenses		10,906			14,154			24,531			26,573
Income from operations		8,749			35,489			34,941			53,608
Interest and other, net
Interest expense		(2,964	)		(2,915	)		(5,915	)		(5,819	)
Interest income and other income (expenses), net		(1,367	)		(2,181	)		(2,649	)		(1,846	)
Total interest and other, net		(4,331	)		(5,096	)		(8,564	)		(7,665	)
Income before income taxes		4,418			30,393			26,377			45,943
Provision for income taxes		—			19			—			45
Investment income in unconsolidated variable interest entity		1,662			1,177			1,108			1,766
Income from discontinued operations, net of tax	$	6,080		$	31,551		$	27,485		$	47,664

The product revenue, net, consists primarily of revenues from sales of roxadustat commercial product to Falikang, a distribution entity jointly owned by AstraZeneca and FibroGen Beijing, and is discussed in the China Performance Obligation section in Note 3, Collaboration Agreements, License Agreement and Revenues.


	June 30, 2025		December 31, 2024
Assets
Cash and cash equivalents	$	96,474	$	51,696
Accounts receivable, net		22,143		18,443
Inventories		10,871		15,547
Prepaid expenses and other current assets		3,162		25,163
Total current assets held for sale		132,650		110,849

Property and equipment, net		4,670		7,041
Equity method investment in unconsolidated variable interest entity		8,115		6,864
Operating lease right-of-use assets		1,122		1,716
Other assets		987		990
Total long-term assets held for sale		14,894		16,611

Liabilities
Accounts payable	$	123	$	26,974
Accrued and other current liabilities		7,486		10,679
Operating lease liabilities, current		849		1,264
Total current liabilities held for sale		8,458		38,917

Operating lease liabilities, non-current		156		356
Total long-term liabilities held for sale		156		356


	Six Months Ended June 30,
	2025			2024
Depreciation	$	530		$	753
Investment loss (income) in unconsolidated variable interest entity		(1,108	)		(1,766	)
Impairment of property and equipment		2,062			—
Stock-based compensation	$	943		$	884

Included in the discontinued operations, Falikang, an entity jointly owned by FibroGen Beijing and AstraZeneca is an unconsolidated VIE accounted for as an equity method investment, and considered as a related party to the Company. FibroGen Beijing owns 51.1% of Falikang’s equity.

The net product revenue from sales to Falikang were $16.4 million and $46.0 million for the three months ended June 30, 2025 and 2024, and $53.3 million and $73.1 million for the six months ended June 30, 2025 and 2024, respectively. The product revenue recognized for the three months ended June 30, 2025 included a decrease in revenue of $12.1 million resulting from changes to estimated variable consideration in the current period relating to performance obligation satisfied in previous periods. The other income from Falikang were immaterial for the three and six months ended June 30, 2025 and 2024.

The investment income in Falikang was $1.7 million and $1.2 million for the three months ended June 30, 2025 and 2024, and $1.1 million and $1.8 million for the six months ended June 30, 2025 and 2024, respectively. As of June 30, 2025 and December 31, 2024, the Company’s equity method investment in Falikang were $8.1 million and $6.9 million, respectively, which were included in the long-term assets held for sale on the condensed consolidated balance sheets.

As of June 30, 2025 and December 31, 2024, accounts receivable, net, from Falikang were $19.1 million and $13.9 million, respectively, which were included in the current assets held for sale on the condensed consolidated balance sheets.

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 23,367	$ 50,482
Accounts receivable, net	136	481
Inventories	3,863	3,155
Prepaid expenses and other current assets	2,306	31,542
Current assets held for sale	132,650	110,849
Total current assets	162,322	196,509
Other assets	839	1,405
Long-term assets held for sale	14,894	16,611
Total assets	178,055	214,525
Current liabilities:
Accounts payable	10,477	5,064
Accrued and other current liabilities	35,916	62,035
Deferred revenue	27,311	27,290
Senior secured term loan facilities, current	73,733	0
Current liabilities held for sale	8,458	38,917
Total current liabilities	155,895	133,306
Product development obligations	19,398	17,012
Deferred revenue, net of current	122,224	114,708
Senior secured term loan facilities, non-current	0	73,092
Liability related to sale of future revenues, non-current	61,306	58,864
Other long-term liabilities	106	822
Long-term liabilities held for sale	156	356
Total liabilities	359,085	398,160
Commitments and Contingencies
Redeemable non-controlling interests	21,480	21,480
Stockholders' deficit:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at June 30, 2025 and December 31, 2024
Common stock, $0.01 par value; 225,000 shares authorized at June 30, 2025 and December 31, 2024; 4,044 and 4,037 shares issued outstanding at June 30, 2025 and December 31, 2024	1,011	1,009
Additional paid-in capital	1,673,249	1,668,620
Accumulated other comprehensive loss	(4,794)	(5,732)
Accumulated deficit	(1,892,463)	(1,889,499)
Total stockholders' deficit attributable to FibroGen	(222,997)	(225,602)
Nonredeemable non-controlling interests	20,487	20,487
Total deficit	(202,510)	(205,115)
Total liabilities, redeemable non-controlling interests and deficit	$ 178,055	$ 214,525

Collaboration Agreements, License Agreement and Revenues - Astellas Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 1,348,000	$ 998,000	$ 4,088,000	$ 26,363,000
Deferred Revenue			27,311,000		27,311,000		$ 27,290,000
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			1,215,000	729,000	3,811,000	25,216,000
Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price, variable consideration from estimated future co-development billing					0
Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price, variable consideration from estimated future co-development billing					$ 0
Astellas Agreement [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received		$ 172,600,000
Additional consideration based on net sales description					the low 20% range of the list price
Aggregate consideration received excluding drug product revenue			105,100,000		$ 105,100,000
Transaction price, variable consideration from estimated future co-development billing			0	0	0	0
Changes in revenue from changes to estimated variable consideration					0
Astellas Agreement [Member] \| Japan [Member] \| License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cash Consideration Received Under Collaboration Agreement			100,300,000		100,300,000
Astellas Agreement [Member] \| Japan [Member] \| Co-development, information sharing & committee services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cash Consideration Received Under Collaboration Agreement			17,100,000		$ 17,100,000
Astellas Agreement [Member] \| Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received	$ 745,000,000
Additional consideration based on net sales description					low 20% range
Aggregate consideration received excluding drug product revenue			685,000,000		$ 685,000,000
Changes in revenue from changes to estimated variable consideration			0
Astellas Agreement [Member] \| Europe [Member] \| License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			0	$ 0	0	$ 0
Cash Consideration Received Under Collaboration Agreement			619,000,000		619,000,000
Astellas Agreement [Member] \| Europe [Member] \| Co-development, information sharing & committee services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cash Consideration Received Under Collaboration Agreement			$ 288,400,000		$ 288,400,000

Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2025

Accounting Policies [Abstract]

Schedule of Weighted Impacts of Outstanding Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share


	Three Months Ended June 30,				Six Months Ended June 30,
	2025		2024		2025		2024
Employee stock options		490		603		500		551
RSUs, PRSUs and TSR awards		36		156		42		157
ESPP		—		18		—		20
		526		777		542		728

Balance Sheet Components

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Components

6. Balance Sheet Components

Cash and Cash Equivalents

Cash and cash equivalents consisted of the following (in thousands):


	June 30, 2025		December 31, 2024
Cash	$	1,504	$	2,004
Commercial paper		12,082		14,269
Money market funds		5,296		28,241
U.S. government bonds		4,485		5,968
Total cash and cash equivalents	$	23,367	$	50,482

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	June 30, 2025		December 31, 2024
Insurance proceeds receivable for litigation settlement	$	—	$	28,500
Prepaid assets		1,031		1,903
Other current assets		1,275		1,139
Total prepaid expenses and other current assets	$	2,306	$	31,542

As of December 31, 2024, the Company recorded a $28.5 million receivable in prepaid expenses and other current assets, corresponding to the accrued litigation settlement of the same amount related to the Company’s agreement in principle with plaintiffs to settle the class action lawsuit. As the Company maintains insurance that covers exposure related to the class action lawsuit, this amount is fully recoverable under the Company’s insurance policies. The determination that the recorded receivables are probable of collection is based on the terms of the applicable insurance policies and communications with the insurers. Such amount was fully distributed during the first quarter of 2025. As a result, the related accrued liability and the corresponding receivable were fully settled in the same period. See the Accrued and Other Current Liabilities section below, and the Legal Proceedings and Other Matters section in Note 10, Commitments and Contingencies, for details.

Accrued and Other Current Liabilities

Accrued and other current liabilities consisted of the following (in thousands):


	June 30, 2025		December 31, 2024
Preclinical and clinical trial accruals	$	5,991	$	6,327
API and bulk drug product price true-up		12,444		13,071
Litigation settlement		—		28,500
Payroll and related accruals		4,998		4,640
Accrued restructuring charge		1,715		4,572
Professional services		6,204		2,049
Current portion of liability related to sale of future revenues		1,702		460
Other		2,862		2,416
Total accrued and other current liabilities	$	35,916	$	62,035

The accrued liabilities of $12.4 million and $13.1 million for API and bulk drug product price true-up as of June 30, 2025 and December 31, 2024, respectively, resulted from changes in estimated variable consideration associated with the API shipments fulfilled under the terms of the Astellas Japan Amendment, and the bulk drug product transferred under the terms of the Astellas Europe Agreement and the Astellas EU Supply Agreement. See the Drug Product Revenue, Net section in Note 3, Collaboration Agreements, License Agreement and Revenues, for details.

As of December 31, 2024, the accrued litigation settlement of $28.5 million was related to the Company’s agreement in principle with plaintiffs to settle the class action lawsuit, which was fully distributed during the first quarter of 2025 as mentioned above. See the Legal Proceedings and Other Matters section in Note 10, Commitments and Contingencies, for details.

Responding to the reported results for pamrevlumab in July 2024, the Company implemented an immediate and significant cost reduction plan in the U.S., including terminating pamrevlumab research and development investment and expeditiously wind down remaining obligations, and reducing U.S. workforce by approximately 75%. The total cash payments under the reduction in force was $0.8 million and $2.4 million during the three and six months ended June 30, 2025, respectively. The remaining accrued restructuring charge of $1.7 million as of June 30, 2025 will be substantially paid out in the second half of 2025.

Discontinued Operations - Schedule of Significant Non-cash Items and Capital Expenditures for Discontinued Operations (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation	$ 530	$ 1,582
Investment loss (income) in unconsolidated variable interest entity	(1,108)	(1,766)
Impairment of property and equipment	2,062	0
Stock-based compensation	4,725	17,350
FibroGen International [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation	530	753
Investment loss (income) in unconsolidated variable interest entity	(1,108)	(1,766)
Impairment of property and equipment	2,062	0
Stock-based compensation	$ 943	$ 884

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended					6 Months Ended		12 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	$ 27,311		$ 27,290			$ 27,311		$ 27,290
Drug product revenue recognized	1,348			$ 998		4,088	$ 26,363
Other long-term liabilities	106		822			106		822
Astra Zeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	16,400			46,000		53,300	73,100
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,215			729		3,811	25,216
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,200			700		3,800	(500)
Drug Product Revenue, Net [Member] \| Europe [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,171			1,095		1,986	2,116
Drug Product Revenue, Net [Member] \| Europe [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Burdened manufacturing costs			600
Drug Product Revenue, Net [Member] \| Japan [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	44			(366)		1,825	(2,571)
Accrued liabilities	600		2,500			600		2,500
Other long-term liabilities			600					600
Drug Product Revenue, Net [Member] \| API Shipment [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized		$ 1,800		400	$ 2,200
Bulk Drug Product [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue			4,400					4,400
Bulk Drug Product [Member] \| Europe [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized						1,300		7,200
Accrued liabilities	11,900		$ 10,500			11,900		$ 10,500
Bulk Drug Product [Member] \| Europe [Member] \| Astellas Europe Agreement [Member] \| Royalty Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty revenue recognized as drug product revenue	$ 1,200			$ 1,100		$ 2,000	$ 2,100

Segment Information - Additional Information (Details)	6 Months Ended
Segment Information - Additional Information (Details)	Jun. 30, 2025 Segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segment	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM assesses performance of the business, monitors budget versus actual results and manages and allocates resources to the Company’s operations using consolidated net income (loss) as the primary measurement.

Collaboration Agreements, License Agreement and Revenues - AstraZeneca Agreements - Additional Information 1 (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jul. 30, 2013	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		$ 1,348	$ 998	$ 4,088	$ 26,363
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		$ 16,400	$ 46,000	53,300	$ 73,100
AstraZeneca Agreements [Member] \| U.S./RoW [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate considerations received				439,000
AstraZeneca Agreements [Member] \| China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent, non-refundable and time-based payments	$ 376,700
Aggregate considerations received				$ 81,200

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (ee)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 5: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
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-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
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-URI https://asc.fasb.org/1943274/2147479941/924-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-URI https://asc.fasb.org/1943274/2147479806/606-10-50-5

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Paragraph 30
-Subparagraph (a)
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-URI https://asc.fasb.org/1943274/2147482810/280-10-50-30

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-42

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
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-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-40

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (a)
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-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-4

+ Details

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2025

Fair Value Disclosures [Abstract]

Fair Values of Financial Assets Measured on Recurring Basis

The fair values of the Company’s financial assets that are measured on a recurring basis are as follows (in thousands):


	June 30, 2025
	Level 1		Level 2		Level 3		Total
Money market funds	$	5,296	$	—	$	—	$	5,296
Commercial paper		—		12,082		—		12,082
U.S. government bonds		3,190		1,295		—		4,485
Total	$	8,486	$	13,377	$	—	$	21,863

	December 31, 2024
	Level 1		Level 2		Level 3		Total
Money market funds	$	28,241	$	—	$	—	$	28,241
Commercial paper		—		14,269		—		14,269
U.S. government bonds		2,987		2,981		—		5,968
Total	$	31,228	$	17,250	$	—	$	48,478

Collaboration Agreements, License Agreement and Revenues - Eluminex Agreement - Additional Information 2 (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2021	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2023	Apr. 30, 2023	Dec. 31, 2022
Revenue Recognition, Milestone Method [Line Items]
Total revenue		$ 1,348	$ 998	$ 4,088	$ 26,363
Eluminex [Member]
Revenue Recognition, Milestone Method [Line Items]
Aggregate consideration received for milestone and upfront payments								$ 8,000
Future manufacturing clinical regulatory and commercial milestone payments	$ 64,000
Commercial milestone	$ 36,000
Additional upfront payments							$ 1,500
Milestone Payments						$ 6,000
Upfront payment						$ 1,500
Total revenue		$ 0	$ 0	$ 0	$ 0

- Definition

+ References

+ Details

Consolidated Variable Interest Entity - Fortis

6 Months Ended

Jun. 30, 2025

Business Combinations [Abstract]

Consolidated Variable Interest Entity - Fortis

4. Consolidated Variable Interest Entity - Fortis

In May 2023 (the “Option Acquisition Date”), the Company entered into an exclusive option agreement to acquire Fortis Therapeutics, Inc. (“Fortis”) with its novel Phase 1 ADC, FOR46 (now referred to as “FG-3246”), that targets a novel epitope on CD46 preferentially expressed on certain cancer cells. FG-3246 is in development for the treatment of mCRPC with potential applicability in other solid tumors and hematologic malignancies. If FibroGen exercises the option to acquire Fortis, it will pay Fortis an option exercise payment of $80.0 million, and thereafter, legacy Fortis shareholders would be eligible to receive from FibroGen up to $200.0 million in contingent payments associated with the achievement of various regulatory approvals. If FibroGen acquires Fortis, it would also be responsible to pay University of California, San Francisco (“UCSF”), an upstream licensor to Fortis, development milestone fees and a single digit royalty on net sales of therapeutic or diagnostic products arising from the licensing arrangement between Fortis and UCSF. If FibroGen chooses not to acquire Fortis, its exclusive license to FG-3246 would expire.

On March 28, 2025, the Company and Fortis entered into amendments and modified the option exercise deadline to December 31, 2027.

Pursuant to an evaluation agreement entered into with Fortis concurrent with the option agreement (together the “Fortis Agreements”), FibroGen has exclusively licensed FG-3246 and will control and fund future research, development, including a Phase 2 clinical study sponsored by FibroGen, and manufacturing of FG-3246 during the up-to four-year option period (which ends on the earlier of 120 days after Fortis or FibroGen submits data from any Phase 2 clinical trial of a product to the U.S. Food and Drug Administration for the purpose of progressing to a Phase 3 clinical trial or December 31, 2027 absent extension). As part of the clinical development strategy, FibroGen will continue the work to develop a PET-based biomarker utilizing a radiolabeled version of the targeting antibody for patient selection. Additionally, the Company is obligated to make four quarterly payments totaling $5.4 million to Fortis in support of its continued development obligations, of which the last payment was $1.7 million and made during the three months ended March 31, 2024.

Pursuant to the guidance under ASC 810, Consolidation (“ASC 810”), the Company determined that Fortis is a VIE and that the Company is the primary beneficiary of Fortis, as through the Fortis Agreements the Company has the power to direct activities that most significantly impact the economic performance of Fortis. Therefore, the Company consolidated Fortis starting from the Option Acquisition Date and continues to consolidate as of June 30, 2025.

Fortis has authorized and issued common shares and Series A preferred shares. As of the Option Acquisition Date and June 30, 2025, the Company owned approximately 2% of Fortis’ Series A preferred shares, which was acquired previously and carried at zero cost. The non-controlling interests (“NCI”) attributable to the common shares is classified as nonredeemable NCI, as it is 100% owned by third party shareholders. The NCI attributable to the approximately 98% of Series A preferred shares owned by other investors are classified as redeemable NCI in temporary equity, as the preferred shares are redeemable by the non-controlling shareholders upon occurrence of certain events out of the Company’s control.

Subsequent to the Option Acquisition Date, Fortis’ net income is allocated to its common shares and preferred shares based on their respective stated rights. Fortis’ net loss is allocated to its common shares only as the holders of preferred shares do not have a contractual obligation to absorb such losses.

As of June 30, 2025, total assets and liabilities of Fortis were immaterial. For the three and six months ended June 30, 2025 and 2024, Fortis’ net income (losses) was immaterial.

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Pay vs Performance Disclosure
Net Income (Loss)	$ (7,603)	$ (15,544)	$ (2,964)	$ (48,477)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-Name Accounting Standards Codification
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-Paragraph 9
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-URI https://asc.fasb.org/1943274/2147483443/250-10-50-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
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-Paragraph 1
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-Publisher FASB
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(3)
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+ Details

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Statement of Comprehensive Income [Abstract]
Net loss	$ (7,603)	$ (15,544)	$ (2,964)	$ (48,477)
Other comprehensive income (loss):
Foreign currency translation adjustments	(360)	2,700	939	3,092
Available-for-sale investments:
Unrealized loss on investments, net of tax effect	0	(2)	(1)	(26)
Other comprehensive income (loss), net of taxes	(360)	2,698	938	3,066
Comprehensive loss	$ (7,963)	$ (12,846)	$ (2,026)	$ (45,411)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

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+ Details

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Operating activities
Net loss	$ (2,964)	$ (48,477)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	530	1,582
Amortization of finance lease right-of-use assets	18	19
Net accretion of premium and discount on investments	(1)	(1,681)
Investment income in unconsolidated variable interest entity	(1,108)	(1,766)
Impairment of property and equipment	2,062	0
Loss on disposal of property and equipment	0	306
Stock-based compensation	4,725	17,350
Changes in operating assets and liabilities:
Accounts receivable, net	(3,001)	5,962
Inventories	4,210	15,578
Prepaid expenses and other current assets	51,479	4,527
Operating lease right-of-use assets	620	6,806
Other assets	549	441
Accounts payable	(21,692)	(7,977)
Accrued and other liabilities	(30,700)	(52,663)
Operating lease liabilities, current	(434)	1,489
Deferred revenues	7,537	(29,501)
Accrued interest expense related to sale of future revenues	3,684	(1,904)
Accrued interest for finance lease liabilities	(11)	12
Operating lease liabilities, non-current	(205)	(8,128)
Other long-term liabilities	103	(1,132)
Net cash provided by (used in) operating activities	15,401	(99,157)
Investing activities
Purchases of property and equipment	(29)	(43)
Proceeds from sale of property and equipment	0	3
Purchases of available-for-sale securities		(8,628)
Proceeds from maturities of investments	0	132,183
Net cash provided by (used in) investing activities	(29)	123,515
Financing activities
Repayments of finance lease liabilities	(2)	(20)
Cash paid for payroll taxes on restricted stock unit releases	(49)	(229)
Payment of issuance cost under ATM Program	(46)	0
Proceeds from issuance of common stock under employee stock plans	0	116
Net cash used in financing activities	(97)	(133)
Effect of exchange rate change on cash and cash equivalents	2,388	2,801
Net increase in cash and cash equivalents	17,663	27,026
Total cash and cash equivalents at beginning of period	102,178	113,688
Total cash and cash equivalents at end of period	$ 119,841	$ 140,714

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Prepaid Expense and Other Assets, Current [Abstract]
Insurance proceeds receivable for litigation settlement	$ 0	$ 28,500
Prepaid assets	1,031	1,903
Other current assets	1,275	1,139
Total prepaid expenses and other current assets	$ 2,306	$ 31,542

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2025	Jul. 31, 2025
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q2
Trading Symbol	FGEN
Entity Registrant Name	FIBROGEN, INC.
Entity Central Index Key	0000921299
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity File Number	001-36740
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0357827
Entity Address, Address Line One	350 Bay Street
Entity Address, Address Line Two	Suite 100, #6009
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94158
City Area Code	415
Local Phone Number	978-1200
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock Shares Outstanding		4,043,899

Consolidated Variable Interest Entity - Fortis - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	May 31, 2023	Mar. 31, 2024	Jun. 30, 2025
Third Party Shareholders [Member] \| Nonredeemable NCI [Member]
Business Acquisition [Line Items]
Ownership percentage	100.00%		100.00%
Other Investors [Member] \| Nonredeemable NCI [Member]
Business Acquisition [Line Items]
Ownership percentage	98.00%		98.00%
Series A Preferred Shares [Member] \| Nonredeemable NCI [Member]
Business Acquisition [Line Items]
Ownership percentage	2.00%		2.00%
Fortis Therapeutics [Member]
Business Acquisition [Line Items]
Payment to options exercised	$ 80.0
Contingent payment associated with business acquisition	200.0
Product development obligations	$ 5.4	$ 1.7

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2025	Dec. 31, 2024
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	125,000,000	125,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	4,044,000	4,037,000
Common stock, shares outstanding	4,044,000	4,037,000

Collaboration Agreements, License Agreement and Revenues - AstraZeneca U.S./RoW Agreement - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Related cost of goods sold	$ 85	$ 140		$ 337	$ 21,483
AstraZeneca U.S./RoW Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cumulative catch-up net adjustment			$ 25,700
Related cost of goods sold			$ 21,100

- Definition

The aggregate cost of goods produced and sold and services rendered during the reporting period.

+ References

+ Details

Segment Information

6 Months Ended

Jun. 30, 2025

Segment Reporting [Abstract]

Segment Information

11. Segment Information

The Company has one operating and reporting segment which primarily focuses on the development and commercialization of novel therapeutics to treat serious unmet medical needs. The Company has determined that the chief executive officer is the chief operating decision maker (“CODM”). The CODM assesses performance of the business, monitors budget versus actual results and manages and allocates resources to the Company’s operations using consolidated net income (loss) as the primary measurement. The CODM is regularly provided with entity-wide expense categories that are consistent with those found on the Company’s condensed consolidated statements of operations. These significant segment expense include cost of goods sold, research and development expenses, selling, general and administrative expenses, and restructuring charge. Other segment items that are presented on the condensed consolidated statements of operations include interest and other income (expense), net, and provision for (benefit from) income taxes. The measure of segment assets is reported on the balance sheet as total consolidated assets.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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+ Details

Senior Secured Term Loan Facilities (Table)

6 Months Ended

Jun. 30, 2025

Debt Disclosure [Abstract]

Summary of Senior Secured Term Loan Facilities

The balances of the Company’s senior secured term loan facilities as of June 30, 2025 and December 31, 2024 were as follows (in thousands):


	June 30, 2025			December 31, 2024
Principal of senior secured term loan facilities	$	75,000		$	75,000
Less: Unamortized issuance costs and transaction costs		(1,267	)		(1,908	)
Senior secured term loan facilities, ending balance	$	73,733		$	73,092
Representing:
Senior secured term loan facilities, current	$	(73,733	)	$	—
Senior secured term loan facilities, non-current	$	—		$	73,092

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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-Topic 470
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-Name Accounting Standards Codification
-Section 55
-Paragraph 69E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E

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-Subparagraph (SX 210.12-04(a))
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-URI https://asc.fasb.org/1943274/2147481112/505-10-50-7

+ Details

Income Taxes

6 Months Ended

Jun. 30, 2025

Income Tax Disclosure [Abstract]

Income Taxes

9. Income Taxes

Provisions for income tax for the three and six months ended June 30, 2025 and 2024 were immaterial and due to foreign taxes.

Based upon the weight of available evidence, which includes its historical operating performance, reported cumulative net losses since inception, the Company has established and continues to maintain a full valuation allowance against its net deferred tax assets as it does not currently believe that realization of those assets is more likely than not.

On July 4, 2025, the One Big Beautiful Bill Act was signed into law in the U.S. which contains a broad range of tax reform provisions affecting businesses. The Company is still in the process of evaluating the legislation and an estimate of the financial impact cannot be made at this time.

- Definition

The entire disclosure for income tax.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482603/740-30-50-2

+ Details

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2025
Fair Value Disclosures [Abstract]
Transfers of assets from level 1 to 2	$ 1.3	$ 7.8

Significant Accounting Policies - Schedule of Weighted Impacts of Outstanding Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	526	777	542	728
Employee stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	490	603	500	551
RSUs, PRSUs and TSR awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	36	156	42	157
ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	0	18	0	20

Condensed Consolidated Statements of Changes in Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member] Redeemable [Member]
Balance at Dec. 31, 2023	$ (183,679)	$ 988	$ 1,643,641	$ (6,875)	$ (1,841,920)	$ 20,487	$ 21,480
Balance, Shares at Dec. 31, 2023		3,950,809
Net loss	(48,477)	$ 0	0	0	(48,477)	0	0
Change in unrealized gain or loss on investments	(26)	0	0	(26)	0	0	0
Foreign currency translation adjustments	3,092	0	0	3,092	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(113)	$ 16	(129)	0	0	0	0
Redemption of fractional shares due to reverse stock split, Shares		(65,181)
Stock-based compensation	17,350	$ 0	17,350	0	0	0	0
Balance at Jun. 30, 2024	(211,853)	$ 1,004	1,660,862	(3,809)	(1,890,397)	20,487	21,480
Balance, Shares at Jun. 30, 2024		4,015,990
Balance at Mar. 31, 2024	(207,635)	$ 995	1,652,243	(6,507)	(1,874,853)	20,487	21,480
Balance, Shares at Mar. 31, 2024		3,978,975
Net loss	(15,544)	$ 0	0	0	(15,544)	0	0
Change in unrealized gain or loss on investments	(2)	0	0	(2)	0	0	0
Foreign currency translation adjustments	2,700	0	0	2,700	0	0	0
Shares issued from stock plans, net of payroll taxes paid	40	$ 9	31	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		37,015
Stock-based compensation	8,588	$ 0	8,588	0	0	0	0
Balance at Jun. 30, 2024	(211,853)	$ 1,004	1,660,862	(3,809)	(1,890,397)	20,487	21,480
Balance, Shares at Jun. 30, 2024		4,015,990
Balance at Dec. 31, 2024	(205,115)	$ 1,009	1,668,620	(5,732)	(1,889,499)	20,487	21,480
Balance, Shares at Dec. 31, 2024		4,036,678
Net loss	(2,964)	$ 0	0	0	(2,964)	0	0
Change in unrealized gain or loss on investments	(1)	0	0	(1)	0	0	0
Foreign currency translation adjustments	939	0	0	939	0	0	0
Issuance cost under ATM Program	(46)	0	(46)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(48)	$ 2	(50)	0		0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		7,276
Redemption of fractional shares due to reverse stock split, Shares		(55)
Redemption of fractional shares due to reverse stock split	0	$ 0	0	0	0	0	0
Stock-based compensation	4,725	0	4,725	0	0	0	0
Balance at Jun. 30, 2025	(202,510)	$ 1,011	1,673,249	(4,794)	(1,892,463)	20,487	21,480
Balance, Shares at Jun. 30, 2025		4,043,899
Balance at Mar. 31, 2025	(196,409)	$ 1,010	1,671,388	(4,434)	(1,884,860)	20,487	21,480
Balance, Shares at Mar. 31, 2025		4,041,758
Net loss	(7,603)	$ 0	0	0	(7,603)	0	0
Foreign currency translation adjustments	(360)	0	0	(360)	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(11)	$ 1	(12)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		2,196
Redemption of fractional shares due to reverse stock split, Shares		(55)
Redemption of fractional shares due to reverse stock split	0	$ 0	0	0	0	0	0
Stock-based compensation	1,873	0	1,873	0	0	0	0
Balance at Jun. 30, 2025	$ (202,510)	$ 1,011	$ 1,673,249	$ (4,794)	$ (1,892,463)	$ 20,487	$ 21,480
Balance, Shares at Jun. 30, 2025		4,043,899

Senior Secured Term Loan Facilities

6 Months Ended

Jun. 30, 2025

Debt Disclosure [Abstract]

Senior Secured Term Loan Facilities

7. Senior Secured Term Loan Facilities

In April 2023, the Company entered into a financing agreement (“Financing Agreement”) with investment funds managed by Morgan Stanley Tactical Value, as lenders (the “Lenders”), and Wilmington Trust, National Association, as the administrative agent, providing for senior secured term loan facilities consisting of (i) a $75.0 million initial term loan (the “Initial Term Loan”), (ii) a $37.5 million delayed draw term loan that will be funded upon the achievement of certain clinical development milestones (“Delayed Draw Term Loan 1”) and, (iii) an uncommitted delayed draw term loan of up to $37.5 million to be funded at the Lenders sole discretion, (“Delayed Draw Term Loan 2” and, together with the Initial Term Loan and Delayed Draw Term Loan 1, the “Term Loans”).

Pursuant to the Financing Agreement, the Lenders have funded the Initial Term Loan. The clinical development milestones which could have triggered Delayed Draw Term Loan 1 were not achieved, and the Lenders have not funded Delayed Draw Term Loan 2. As such, these features expired during 2023. The Company has determined that certain other features embedded within the Loan should be bifurcated and accounted for separately as a derivative. At inception and as of June 30, 2025, the fair values of such derivatives were negligible due to the low probability of the underlying events.

The Term Loans shall accrue interest at a fixed rate of 14.0% per annum, payable monthly in arrears. The Term Loans shall mature on May 8, 2026. Therefore, the balance of the Term Loans was included in senior secured term loan facilities, current, under the current liabilities on the condensed consolidated balance sheet as of June 30, 2025. The Term Loans will not be subject to amortization payments. The Company is permitted to prepay the Term Loans from time to time, in whole or in part, subject to payment of a make-whole amount equal to the unpaid principal amount of the portion of the Term Loans being repaid or prepaid, plus accrued and unpaid interest of the portion of the Term Loans being repaid or prepaid, plus an amount equal to the remaining scheduled interest payments due on such portion of the Term Loans being repaid or prepaid as if such Term Loans were to remain outstanding until the scheduled maturity date.

The initial issuance costs and the related transaction costs, totaling $3.7 million is amortized as interest expense using the effective interest method over the term of the Initial Term Loan and are reported on the balance sheet as a direct deduction from the amount of the Initial Term Loan. The effective annual interest rate of the Initial Term Loan was 16.13% for the three and six months ended June 30, 2025 and 2024. The Company recorded interest expense of $3.0 million and $5.9 million for the three and six months ended June 30, 2025, and $2.9 million and $5.8 million for the three and six months ended June 30, 2024, respectively, which were included in discontinued operations as the Company is required to repay the loan upon the closing of the divestiture of FibroGen International.

As of June 30, 2025, the related accrued interest was $0.4 million. The Company was in compliance with all debt covenants associated with the senior secured term loan facilities as of June 30, 2025, including maintaining a minimum balance of $22.5 million of unrestricted cash and cash equivalents held in accounts in the U.S.; such minimum balance covenant was subsequently amended to be $18.75 million on July 14, 2025 by the Company and the Lenders.

The balances of the Company’s senior secured term loan facilities as of June 30, 2025 and December 31, 2024 were as follows (in thousands):


	June 30, 2025			December 31, 2024
Principal of senior secured term loan facilities	$	75,000		$	75,000
Less: Unamortized issuance costs and transaction costs		(1,267	)		(1,908	)
Senior secured term loan facilities, ending balance	$	73,733		$	73,092
Representing:
Senior secured term loan facilities, current	$	(73,733	)	$	—
Senior secured term loan facilities, non-current	$	—		$	73,092

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
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+ Details

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Cash and Cash Equivalents

Cash and cash equivalents consisted of the following (in thousands):


	June 30, 2025		December 31, 2024
Cash	$	1,504	$	2,004
Commercial paper		12,082		14,269
Money market funds		5,296		28,241
U.S. government bonds		4,485		5,968
Total cash and cash equivalents	$	23,367	$	50,482

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	June 30, 2025		December 31, 2024
Insurance proceeds receivable for litigation settlement	$	—	$	28,500
Prepaid assets		1,031		1,903
Other current assets		1,275		1,139
Total prepaid expenses and other current assets	$	2,306	$	31,542

Schedule of Accrued and Other Current Liabilities

Accrued and other current liabilities consisted of the following (in thousands):


	June 30, 2025		December 31, 2024
Preclinical and clinical trial accruals	$	5,991	$	6,327
API and bulk drug product price true-up		12,444		13,071
Litigation settlement		—		28,500
Payroll and related accruals		4,998		4,640
Accrued restructuring charge		1,715		4,572
Professional services		6,204		2,049
Current portion of liability related to sale of future revenues		1,702		460
Other		2,862		2,416
Total accrued and other current liabilities	$	35,916	$	62,035

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Summary of Drug Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 1,348	$ 998	$ 4,088	$ 26,363
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	16,400	46,000	53,300	73,100
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,215	729	3,811	25,216
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,200	700	3,800	(500)
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	44	(366)	1,825	(2,571)
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,171	1,095	1,986	2,116
Drug Product Revenue, Net [Member] \| AstraZeneca Agreements [Member] \| U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 0	$ 0	$ 0	$ 25,671

- Definition

+ References

+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Jun. 30, 2025
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Rule 10b5-1 Trading Arrangements None.
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Cash and Cash Equivalents [Abstract]
Cash	$ 1,504	$ 2,004
Commercial paper	12,082	14,269
Money market funds	5,296	28,241
U.S. government bonds	4,485	5,968
Total cash and cash equivalents	$ 23,367	$ 50,482

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References + Details

Collaboration Agreements, License Agreement and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - AstraZeneca Agreements [Member] - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Contract with Customer, Liability [Abstract]
Deferred Revenue	$ 142,947	$ 132,097
China [Member]
Contract with Customer, Liability [Abstract]
Deferred Revenue	$ 20,700

Senior Secured Term Loan Facilities - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2023	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Jul. 14, 2025
Debt Instrument [Line Items]
Accrued interest		$ 400		$ 400
Minimum [Member]
Debt Instrument [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts		18,750		$ 18,750
Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Interest rate per annum	14.00%
Maturity date	May 08, 2026
Repayment description				The Term Loans shall mature on May 8, 2026. Therefore, the balance of the Term Loans was included in senior secured term loan facilities, current, under the current liabilities on the condensed consolidated balance sheet as of June 30, 2025. The Term Loans will not be subject to amortization payments. The Company is permitted to prepay the Term Loans from time to time, in whole or in part, subject to payment of a make-whole amount equal to the unpaid principal amount of the portion of the Term Loans being repaid or prepaid, plus accrued and unpaid interest of the portion of the Term Loans being repaid or prepaid, plus an amount equal to the remaining scheduled interest payments due on such portion of the Term Loans being repaid or prepaid as if such Term Loans were to remain outstanding until the scheduled maturity date.
Debt Financing Agreement [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts		$ 22,500		$ 22,500
Debt Financing Agreement [Member] \| Minimum [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts						$ 18,750
Initial Term Loan [Member]
Debt Instrument [Line Items]
Interest rate per annum		16.13%	16.13%	16.13%	16.13%
Issuance costs and related transaction costs, amortised		$ 3,700		$ 3,700
Initial Term Loan [Member] \| Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Term loan	$ 75,000
Delayed Draw Term Loan [Member] \| Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Term loan	37,500
Delayed Draw Term Loan 2 \| Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Term loan	$ 37,500
FibroGen International [Member]
Debt Instrument [Line Items]
Interest expense		$ 3,000	$ 2,900	$ 5,900	$ 5,800

Significant Accounting Policies

6 Months Ended

Jun. 30, 2025

Accounting Policies [Abstract]

Significant Accounting Policies

1. Significant Accounting Policies

Description of Operations

FibroGen, Inc. (“FibroGen” or the “Company”) is a biopharmaceutical company focused on development of novel therapies at the frontiers of cancer biology and anemia.

The Company is developing FG-3246, a potential first-in-class antibody-drug conjugate (“ADC”) targeting CD46, for the treatment of metastatic castration-resistant prostate cancer (“mCRPC”) and potentially other cancers. This program also includes the development of FG-3180, an associated CD46-targeted positron emission tomography (“PET”) biomarker and imaging agent. The Company anticipates initiation of a Phase 2 monotherapy dose optimization study of FG-3246 for the treatment of mCRPC, along with the exploratory analysis of FG-3180, in the third quarter of 2025, pending close of the sale of FibroGen International to AstraZeneca Treasury Limited.

The Company and its collaboration partners have developed roxadustat (爱瑞卓®, EVRENZOTM), which is currently approved in the People’s Republic of China (“China”), Europe, Japan, and numerous other countries for the treatment of anemia in chronic kidney disease (“CKD”) patients on dialysis and not on dialysis.

On February 20, 2025, the Company entered into a share purchase agreement (the “Share Purchase Agreement”) with AstraZeneca Treasury Limited pursuant to which FibroGen and its subsidiary FibroGen China Anemia Holdings, Ltd. agreed to sell all of the issued and outstanding equity interests of FibroGen International (Hong Kong) Ltd. (“FibroGen International”) to AstraZeneca Treasury Limited. AstraZeneca AB (“AstraZeneca”) is the Company’s long-time commercialization partner for roxadustat in greater China and South Korea. This sale includes all of FibroGen’s roxadustat assets in China, including FibroGen International’s subsidiary FibroGen (China) Medical Technology Development Co., Ltd (“FibroGen Beijing”) and its 51.1% interest in Beijing Falikang Pharmaceutical Co., Ltd. (“Falikang”). The transaction is expected to close in the third quarter of 2025, and is subject to customary closing conditions and closing deliverables, including receipt of regulatory approval from the China State Administration for Market Regulation (“SAMR”).

FibroGen has retained the rights to roxadustat in the United States of America (“U.S.”), Canada, Mexico, and in all markets not held by AstraZeneca or licensed to Astellas Pharma Inc. (“Astellas”). Roxadustat is not approved for commercialization in any indication in the U.S., Canada, or Mexico. Astellas is commercializing roxadustat (EVRENZOTM) in Europe and Japan to treat anemia under two development and commercialization license agreements: one for Japan, and one for Europe, the Commonwealth of Independent States, the Middle East and South Africa.

The Company continues to work on its development plan for roxadustat in anemia associated with lower-risk myelodysplastic syndromes (“MDS”), a high-value indication with significant unmet medical need.

Basis of Presentation and Principles of Consolidation

The unaudited condensed consolidated financial statements and related disclosures have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) applicable to interim financial reporting and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X of the U.S. Securities and Exchange Commission (“SEC”) and, therefore, do not include all information and footnote disclosures normally included in the annual consolidated financial statements. The financial information included herein should be read in conjunction with the consolidated financial statements and related notes in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, filed on March 17, 2025.

The condensed consolidated financial statements include the accounts of FibroGen, its wholly-owned subsidiaries and its majority-owned subsidiaries, as well as any variable interest entity (“VIE”) for which FibroGen is the primary beneficiary. All inter-company transactions and balances have been eliminated in consolidation.

The Company operates as one reportable segment — the development and commercialization of novel therapeutics to treat serious unmet medical needs.

Discontinued Operations

Reverse Stock Split

On June 16, 2025, the Company effected a 1-for-25 reverse stock split (the “Reverse Stock Split”). The Reverse Stock Split reduced the number of issued and outstanding shares of common stock from approximately 101.1 million shares to approximately 4.0 million shares. Proportionate adjustments have been made to the number of shares available for issuance under the Company’s equity incentive plans as well as outstanding equity awards, in accordance with their respective terms. All share amounts have been retroactively adjusted in the condensed consolidated financial statements and the notes to the condensed consolidated financial statements, where applicable, to reflect the Reverse Stock Split.

Liquidity and Going Concern

The unaudited condensed consolidated financial statements are prepared in accordance with the U.S. GAAP applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business and does not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described below.

If the Company is unable to complete the above mentioned sale of FibroGen International, access additional cash from its China operations, or raise additional capital in the U.S., the Company would not have sufficient liquidity to continue operations in the U.S. for the 12 months from the date that the financial statements are issued and would not be able to comply with its financial covenant that requires a minimum balance of $18.75 million of unrestricted cash and cash equivalents to be held in accounts in the United States. Upon an event of default, the Company’s senior secured term loan facilities could become immediately due and payable. The Company has evaluated measures to access additional cash from its China operations and believes the sale of FibroGen International represents the most efficient way to access the entirety of its cash from China upon closing of the transaction. There is also the potential that the Company raises additional funds in the U.S. at any time through equity, equity-linked, or debt financing arrangements or from other sources. There can be no assurances that these plans will be successful. As a result of these factors, the Company has determined that there is substantial doubt about its ability to continue as a going concern within 12 months after the date that the financial statements are issued.

Use of Estimates

Significant Accounting Policies

The accounting policies used by the Company in its presentation of interim financial results are consistent with those presented in Note 2 to the consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, filed on March 17, 2025.

Net Income (Loss) per Share


	Three Months Ended June 30,				Six Months Ended June 30,
	2025		2024		2025		2024
Employee stock options		490		603		500		551
RSUs, PRSUs and TSR awards		36		156		42		157
ESPP		—		18		—		20
		526		777		542		728

Risks and Uncertainties

The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, the results of clinical trials and the achievement of milestones, research developments, actions by regulatory authorities, market acceptance of the Company’s product candidates, competition from other products and larger companies, the liquidity and capital resources of the Company, intellectual property protection for the Company’s proprietary technology, strategic relationships, and dependence on key individuals, suppliers, clinical organization, and other third parties.

Recently Issued Accounting Guidance Not Yet Adopted

In November 2024, the FASB issued Accounting Standards Update (“ASU”) 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40), and relevantly in January 2025, the FASB issued ASU 2025-01, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date. The guidance requires entities to disaggregate operating expenses into specific categories to provide enhanced transparency into the nature and function of expenses. This guidance is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. This guidance should be applied either prospectively to financial statements issued for reporting periods after the effective date or retrospectively to any or all prior periods presented in the financial statements. The Company is currently in the process of evaluating the effects of this guidance on its related disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires enhanced income tax disclosures, including specific categories and disaggregation of information in the effective tax rate reconciliation, disaggregated information related to income taxes paid, income or loss from continuing operations before income tax expense or benefit, and income tax expense or benefit from continuing operations. This guidance is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently in the process of evaluating the impact of this pronouncement on its related disclosures.

Collaboration Agreements, License Agreement and Revenues - Roll-forward of Related Contract Liabilities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2025 USD ($)
AstraZeneca Agreements [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2024	$ (132,097)
Additions	(63,509)
Recognized as Revenue (Discontinued Operations)	53,308
Currency Translation and Other	(649)
Balance at June 30, 2025	(142,947)
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Europe [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2024	(9,901)
Recognized as Revenue	1,986
Reclassified to Accrued Liability / Accounts Payable	1,327
Balance at June 30, 2025	$ (6,588)

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenue:
Total revenue	$ 1,348	$ 998	$ 4,088	$ 26,363
Operating costs and expenses:
Cost of goods sold	$ 85	$ 140	$ 337	$ 21,483
Cost, Product and Service [Extensible List]	Product Revenue, Net [Member]	Product Revenue, Net [Member]	Product Revenue, Net [Member]	Product Revenue, Net [Member]
Research and development	$ 5,865	$ 32,360	$ 15,040	$ 68,848
Selling, general and administrative	7,057	14,906	15,164	31,622
Restructuring charge	393	0	519	0
Total operating costs and expenses	13,400	47,406	31,060	121,953
Loss from operations	(12,052)	(46,408)	(26,972)	(95,590)
Interest and other, net
Interest expense	(2,009)	(1,868)	(4,265)	(3,960)
Interest income and other income (expenses), net	286	900	698	3,135
Total interest and other, net	(1,723)	(968)	(3,567)	(825)
Loss from continuing operations before income taxes	(13,775)	(47,376)	(30,539)	(96,415)
Benefit from income taxes	(92)	(281)	(90)	(274)
Loss from continuing operations	(13,683)	(47,095)	(30,449)	(96,141)
Income from discontinued operations, net of tax	6,080	31,551	27,485	47,664
Net loss	$ (7,603)	$ (15,544)	$ (2,964)	$ (48,477)
Loss from continuing operations per share - basic	$ (3.38)	$ (11.79)	$ (7.54)	$ (24.18)
Loss from continuing operations per share - diluted	(3.38)	(11.79)	(7.54)	(24.18)
Income from discontinued operations per share - basic	1.5	7.9	6.81	11.99
Income from discontinued operations per share - diluted	1.5	7.9	6.81	11.99
Net loss per share - basic	(1.88)	(3.89)	(0.73)	(12.19)
Net loss per share - diluted	$ (1.88)	$ (3.89)	$ (0.73)	$ (12.19)
Weighted average number of common shares used to calculate net income (loss) per share:
Basic	4,042	3,993	4,040	3,976
Diluted	4,042	3,993	4,040	3,976
Development and Other Revenue [Member]
Revenue:
Total revenue	$ 133	$ 269	$ 277	$ 1,147
Drug Product Revenue, Net [Member]
Revenue:
Total revenue	$ 1,215	$ 729	$ 3,811	$ 25,216

Commitments and Contingencies

6 Months Ended

Jun. 30, 2025

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

10. Commitments and Contingencies

Contract Obligations

As of June 30, 2025, the Company had outstanding total non-cancelable purchase obligations of $3.1 million for general purchases and other programs and $0.5 million for manufacture and supply of roxadustat. The Company expects to fulfill its commitments under these agreements in the normal course of business, and as such, no liability has been recorded.

In addition, see Note 7, Senior Secured Term Loan Facilities and Note 8, Liability Related to Sale of Future Revenues for details of the related obligations.

Legal Proceedings and Other Matters

From time to time, the Company is a party to various legal actions, both inside and outside the U.S., arising in the ordinary course of its business or otherwise. The Company accrues amounts, to the extent they can be reasonably estimated, that the Company believes will result in a probable loss (including, among other things, probable settlement value) to adequately address any liabilities related to legal proceedings and other loss contingencies. A loss or a range of loss is disclosed when it is reasonably possible that a material loss will incur and can be estimated, or when it is reasonably possible that the amount of a loss, when material, will exceed the recorded provision. The Company did not have any material accruals for any active legal action, except for the class action settlement mentioned below, in its condensed consolidated balance sheet as of June 30, 2025, as the Company could not predict the ultimate outcome of these matters, or reasonably estimate the potential exposure.

Between April 2021 and May 2021, five putative securities class action complaints were filed against FibroGen and certain of its former executive officers (collectively, the “Defendants”) in the U.S. District Court for the Northern District of California. The lawsuits allege that Defendants violated the Securities Exchange Act of 1934 by making materially false and misleading statements regarding FibroGen’s Phase 3 clinical studies data and prospects for U.S. Food and Drug Administration approval. On August 30, 2021, the Court consolidated the actions and appointed a group of lead plaintiffs. On October 17, 2023, the parties reached an agreement in principle to settle the class action at $28.5 million. Accordingly, as of December 31, 2024, the Company recorded the $28.5 million in accrued and other current liabilities on the condensed consolidated balance sheet. The Company maintains insurance that covers exposure related to the class action lawsuit. As the amount is fully recoverable under the Company’s insurance policies, the Company recorded a corresponding receivable in prepaid expenses and other current assets on the condensed consolidated balance sheet as of December 31, 2024. The determination that the recorded receivables are probable of collection is based on the terms of the applicable insurance policies and communications with the insurers. The Court preliminarily approved the settlement on February 13, 2024 and approved the settlement Plan of Allocation on May 28, 2024 and Plaintiffs’ motion for attorney’s fees on August 1, 2024, reserving further orders on the final judgment until after the claims and distribution process was completed. The court entered a class distribution order on January 1, 2025 and the amount was fully distributed during the first quarter of 2025. As a result, the related accrued liability and the corresponding receivable were fully settled in the same period. Another case, filed on May 25, 2023, against the same defendants, asserting similar claims as the class action and additional common-law and California state fraud claims was voluntarily dismissed on December 20, 2023.

Between July 30, 2021 and April 3, 2024, seven shareholder derivative complaints were filed, naming as defendants certain of the Company’s current and former officers and certain current and former members of the Company’s board, as well as FibroGen as nominal defendants (the “Derivative Lawsuits”). Of these Derivative Lawsuits, four were filed in the Delaware Court of Chancery, two were filed in the U.S. District Court for the District of Delaware (the “Delaware Federal Derivative Actions”), and one was filed in the U.S. District Court for the Northern District of California (the “California Federal Derivative Action”). The plaintiffs assert state and federal claims based on some of the same alleged misstatements as the securities class action complaint. The complaints seek unspecified damages, attorneys’ fees, and other costs. All seven Derivative Lawsuits have been dismissed.

In the fourth quarter of 2021, the Company received a subpoena from the SEC requesting documents related to roxadustat’s pooled cardiovascular safety data. The SEC followed up with a subpoena for additional documents in the second quarter of 2024. In May 2025, the Company entered into a settlement with the SEC, subject to Commission approval. As part of the settlement, and without admitting or denying the findings in the settlement offer or administrative order to be issued by the SEC, the Company agreed to pay a $1.25 million civil penalty.

Between 2022 and 2024, the Company’s Board of Directors received seven litigation demands from purported shareholders of the Company, asking the Board of Directors to investigate and take action against certain current and former officers and directors of the Company for alleged wrongdoing based on the same allegations in the pending derivative and securities class action lawsuits. The Company may in the future receive additional similar demands.

Starting in October 2021, certain challenges have been filed with the China National Intellectual Property Administration against patents which claim a crystalline form of roxadustat. Final resolution of such proceedings will take time and the Company could not predict the ultimate outcome, or reasonably estimate the potential exposure.

Indemnification Agreements

The Company enters into standard indemnification arrangements in the ordinary course of business, including for example, service, manufacturing and collaboration agreements. Pursuant to these arrangements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, including in connection with intellectual property infringement claims by any third party with respect to its technology. The term of these indemnification agreements is generally perpetual any time after the execution of the agreement. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the extent permissible under applicable law. The maximum potential amount of future payments the Company could be required to make under these arrangements is not determinable. The Company believes the estimated fair value of these arrangements is minimal.

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Related Party Transaction [Line Items]
Accounts receivable from related parties	$ 136		$ 136		$ 481
Falikang [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	19,100		19,100		$ 13,900
Investment income	1,700	$ 1,200	$ 1,100	$ 1,800
Percentage of outstanding shares owned			51.10%
Falikang [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenues	$ 16,400	$ 46,000	$ 53,300	$ 73,100

- Definition

Amount of income (loss) for proportionate share of equity method investee's income (loss).

+ References + Details

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details