0000950170-24-125388 | 10-Q | XBRL Viewer

Fair Value Measurements

9 Months Ended

Sep. 30, 2024

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):


	September 30, 2024
	Level 1		Level 2		Level 3		Total
Money market funds	$	49,196	$	—	$	—	$	49,196
Commercial paper		—		25,631		—		25,631
Total	$	49,196	$	25,631	$	—	$	74,827

	December 31, 2023
	Level 1		Level 2		Level 3		Total
Money market funds	$	12,288	$	—	$	—	$	12,288
Corporate bonds		—		13,992		—		13,992
Commercial paper		—		88,289		—		88,289
U.S. government bonds		42,797		4,994		—		47,791
Agency bonds		—		9,830		—		9,830
Total	$	55,085	$	117,105	$	—	$	172,190

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. There were no transfers of assets between levels during the three months ended September 30, 2024 and June 30, 2024. During the three months ended March 31, 2024, a total of $26.3 million 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Collaboration Agreements, License Agreement and Revenues (Tables)

9 Months Ended

Sep. 30, 2024

Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations and Product Revenue Net

Product revenue, net from the sales of roxadustat commercial product in China was as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Direct Sales:
Gross revenue	$	4,355		$	3,186		$	12,186		$	9,853
Discounts and rebates		(363	)		(261	)		(1,130	)		(763	)
Sales returns		(3	)		2			(4	)		2
Direct sales revenue, net		3,989			2,927			11,052			9,092

Sales to Falikang:
Gross transaction price		53,696			42,294			146,608			118,696
Profit share		(23,973	)		(18,130	)		(64,393	)		(51,430	)
Net transaction price		29,723			24,164			82,215			67,266
Decrease in deferred revenue		12,498			2,299			33,124			1,081
Sales to Falikang revenue, net		42,221			26,463			115,339			68,347
Total product revenue, net	$	46,210		$	29,390		$	126,391		$	77,439

Schedule of Drug Product Revenue

Drug product revenue from commercial-grade active pharmaceutical ingredient (“API”) or bulk drug product sales to Astellas and AstraZeneca was as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


	Three Months Ended September 30,					Nine Months Ended September 30,
	2024			2023		2024			2023
Astellas Japan Agreement	$	(1,355	)	$	695	$	(3,926	)	$	16,236
Astellas Europe Agreement		1,093			625		3,209			1,465
AstraZeneca U.S./RoW Agreement		—			—		25,671			—
Drug product revenue, net	$	(262	)	$	1,320	$	24,954		$	17,701

Summary of Amounts Recognized as Revenue

Amounts recognized as revenue under the agreements with Eluminex were as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2024		2023		2024		2023
Eluminex	License revenue	$	—	$	—	$	—	$	7,000
	Other revenue - contract manufacturing		—		241		116		723
	Other revenue - patent transfer	$	—		500	$	—		500

Drug Product Revenue, Net [Member]

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, 2023			Recognized as Revenue		Reclassified to Accrued Liability / Accounts Payable		Balance at September 30, 2024
Drug product revenue - deferred revenue:
Astellas Europe Agreement	$	(16,925	)	$	3,210	$	5,605	$	(8,110	)

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, 2023			Additions			Recognized as Revenue		Currency Translation and Other			Balance at September 30, 2024
Product revenue - AstraZeneca China performance obligation - deferred revenue	$	(179,851	)	$	(82,185	)	$	115,339	$	(270	)	$	(146,967	)

Japan [Member]

Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations and Product Revenue Net

The transaction price related to consideration received through September 30, 2024 and accounts receivable has been allocated to each of the performance obligations under the Astellas Japan Agreement, including $100.3 million for license and $17.1 million for co-development.

Europe [Member]

Summary of License Revenue and Development Revenue Recognized under Agreement

Amounts recognized as license revenue and development revenue under the Astellas Europe Agreement were as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2024		2023		2024		2023
Astellas Europe Agreement	Development revenue	$	382	$	2,322	$	987	$	5,657

U.S./RoW and China [Member]

Summary of License Revenue and Development Revenue Recognized under Agreement

Amounts recognized as license revenue and development revenue under the AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement were as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2024		2023		2024		2023
AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement	License revenue	$	—	$	2,649	$	—	$	2,649
	Development revenue	$	—	$	3,676	$	418	$	7,981

Balance Sheet Components - Summary of Available for Sale Securities in Unrealized Loss Position, Fair Value and Gross Unrealized Loss By Length of Time Security in Continual Unrealized Loss Position (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Available for sale securities in continual unrealized loss position, less than 12 months, estimated fair value	$ 9,971
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	(1)
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	3,495
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	(5)
Available for sale securities in continual unrealized loss position, estimated fair value	13,466
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	(6)
Corporate bonds [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Available for sale securities in continual unrealized loss position, less than 12 months, estimated fair value	0
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	0
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	3,495
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	(5)
Available for sale securities in continual unrealized loss position, estimated fair value	3,495
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	(5)
U.S. government bonds [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Available for sale securities in continual unrealized loss position, less than 12 months, estimated fair value	4,984
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	0
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	0
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	0
Available for sale securities in continual unrealized loss position, estimated fair value	4,984
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	0
Agency bonds [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Available for sale securities in continual unrealized loss position, less than 12 months, estimated fair value	4,987
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	(1)
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	0
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	0
Available for sale securities in continual unrealized loss position, estimated fair value	4,987
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	$ (1)

Liability Related to Sale of Future Revenues - Additional Information (Detail) - USD ($)		3 Months Ended			9 Months Ended
	Nov. 04, 2022	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		$ 46,333,000		$ 40,134,000	$ 152,877,000	$ 120,614,000
Interest expense related to sale of future revenues					5,768,000
Interest paid			$ (5,700,000)		$ (5,653,000)
NovaQuest Capital Management [Member] \| Revenue Interest Financing Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Effective annual interest rate related to sale of future revenues					15.59%
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]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		46,210,000		29,390,000	$ 126,391,000	77,439,000
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
License [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		0		2,649,000	0	9,649,000
Other Revenue - Contract Manufacturing [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		385,000		6,775,000	1,532,000	15,825,000
Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future revenue granted	$ 50,000,000
Percentage of revenue interest on global net sales	100.00%
Astellas Agreement [Member] \| Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue payment cap amount		125,000,000			125,000,000
Astellas Agreement [Member] \| Product [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of revenue sold	22.50%
Astellas Agreement [Member] \| Milestone payments [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of revenue sold	10.00%
Astellas Agreement [Member] \| Milestone payments [Member] \| Payment Period One [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of revenue sold	20.00%
Development Revenue [Member] \| Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		400,000			1,000,000
Drug Product Revenue [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		(262,000)		1,320,000	24,954,000	17,701,000
Drug Product Revenue [Member] \| Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		300,000			700,000
Non-cash interest expense related to drug product revenue		$ 2,000,000		$ 2,100,000	$ 5,800,000	$ 5,600,000

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (17,084)	$ (63,615)	$ (65,561)	$ (228,000)
Other comprehensive income (loss):
Foreign currency translation adjustments	(1,821)	(1,033)	1,271	(3,618)
Available-for-sale investments:
Unrealized gain (loss) on investments, net of tax effect	2	360	(24)	2,415
Other comprehensive gain (loss), net of taxes	(1,819)	(673)	1,247	(1,203)
Comprehensive loss	$ (18,903)	$ (64,288)	$ (64,314)	$ (229,203)

- 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

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- Definition

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

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+ Details

Commitments and Contingencies

9 Months Ended

Sep. 30, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

Contract Obligations

As of September 30, 2024, the Company had outstanding total non-cancelable purchase obligations of $1.0 million for manufacture and supply of roxadustat, and $6.0 million for other purchases and programs. The Company expects to fulfill its commitments under these agreements in the normal course of business, and as such, no liability has been recorded.

Some of the Company’s license agreements provide for periodic maintenance fees over specified time periods, as well as payments by the Company upon the achievement of development, regulatory and commercial milestones. As of September 30, 2024, future milestone payments for research and preclinical stage development programs consisted of up to approximately $697.9 million in total potential future milestone payments under the Company’s license agreements with HiFiBiO (HK) Ltd. (d.b.a. HiFiBiO Therapeutics) (for Gal-9 and CCR8), and Medarex, Inc. These milestone payments generally become due and payable only upon the achievement of certain developmental, clinical, regulatory and/or commercial milestones. The event triggering such payment or obligation has not yet occurred.

As of September 30, 2024, the Company had $2.0 million of operating lease liabilities.

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 September 30, 2024, 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 current and 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, 2023, the Company recorded the $28.5 million in accrued and other current liabilities in the 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 in the condensed consolidated balance sheet. 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 Allocations 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. 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 our current and former officers and certain current and former members of our board, as well as FibroGen as nominal defendants (the “Derivative Lawsuits”). Of these Derivative Lawsuits, four were filed in the Delaware Court of Chancery (the “Delaware Chancery Derivative Actions”), 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. The status of the seven Derivative Lawsuits is currently as follows:

•

Two of the Delaware Chancery Derivative Actions, filed on April 14, 2022, and June 1, 2023, have been consolidated (the “Delaware Chancery Consolidated Derivative”). On February 1, 2024, Defendants moved to dismiss the Delaware Chancery Consolidated Derivative action, which the Court granted on October 2, 2024. The Delaware Chancery Consolidated Derivative was dismissed with prejudice on October 30, 2024. The other two Delaware Chancery Derivative Actions, filed in the Delaware Court of Chancery on December 3, 2023 and April 3, 2024, were consolidated and stayed pending resolution of the motion to dismiss the Delaware Chancery Consolidated Derivative action;

•

The Delaware Federal Derivative Actions remain stayed pending resolution of the motion to dismiss the Delaware Chancery Consolidated Derivative action; and

•

The California Federal Derivative Action was voluntarily dismissed on January 22, 2024.

The Company believes that the claims asserted in the Derivative Lawsuits are without merit and it intends to vigorously defend against them. However, any litigation is inherently uncertain, and any judgment or injunctive relief entered against FibroGen, or any adverse settlement could materially and adversely impact its business, results of operations, financial condition, and prospects.

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. The Company is fully cooperating with the SEC, and is currently discussing with the SEC for a potential settlement. The Company cannot predict the outcome. Any adverse outcome in this matter or any related proceeding could expose the Company to substantial damages, penalties, or reputational harm that may have a material adverse impact on the Company’s business, results of operations, financial condition, growth prospects, and price of its common stock.

Between 2022 and 2024, the Company’s Board of Directors received six 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 such additional 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.

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule of Investments [Abstract]
Raw materials	$ 948	$ 1,376
Work-in-progress	17,775	34,614
Finished goods	5,214	5,575
Total inventories	$ 23,937	$ 41,565

Collaboration Agreements, License Agreement and Revenues - Summary of License Revenue and Development Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenue	$ 46,333	$ 40,134	$ 152,877	$ 120,614
License Revenue [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	2,649	0	9,649
Development Revenue [Member]
Disaggregation of Revenue [Line Items]
Total revenue	385	6,775	1,532	15,825
Astellas Agreement [Member] \| License Revenue [Member] \| Europe [Member]
Disaggregation of Revenue [Line Items]
Total revenue	382	2,322	987	5,657
AstraZeneca Agreements [Member] \| License Revenue [Member] \| U.S./RoW and China [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	2,649	0	2,649
AstraZeneca Agreements [Member] \| Development Revenue [Member] \| U.S./RoW and China [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 0	$ 3,676	$ 418	$ 7,981

- 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

- 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.

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+ Details

Liability Related to Sale of Future Revenues

9 Months Ended

Sep. 30, 2024

8. Liability Related to Sale of Future Revenues

On November 4, 2022, the Company entered into a Revenue Interest Financing Agreement (the “RIFA”) with an affiliate of NovaQuest Capital Management (“NovaQuest”), pursuant to which the Company granted NovaQuest 22.5% of its drug product revenue and 10.0% (20.0% for fiscal year 2028 and thereafter) of its revenue from milestone payments that it is entitled to under the Astellas Agreements, for a consideration of $50.0 million (“Investment Amount”) before advisory fees.

In November 2022, the Company received the Investment Amount, net of initial issuance costs, and accounted for it as long-term debt based on the terms of the RIFA because the risks and rewards to NovaQuest are limited by the terms of the transaction. The related debt discount and transaction costs are amortized as interest expense based on the projected balance of the liability as of the beginning of each period. As payments are made to NovaQuest, the balance of the liability related to sale of future revenues is being effectively repaid over the life of the RIFA. The payments to NovaQuest are accounted for as a reduction of debt.

The Company may prepay its obligations to NovaQuest in full at any time during the term of RIFA. The prepayment amount varies from $80.0 million to $125.0 million less any revenue interest payments made up to such prepayment date. Under the RIFA the Company shall pay to NovaQuest up to a specified maximum amount (“Payment Cap”) of (a) $100.0 million, if the payment is made on or before December 31, 2028; (b) $112.5 million, if the payment is made on or after January 1, 2029, but on or before December 31, 2029; or (c) $125.0 million, if the payment is made after January 1, 2030.

After January 1, 2028, if the product (as defined) is not commercialized for a consecutive twelve-month period, then, the payments owed under the RIFA by the Company to NovaQuest for each fiscal year shall be the greater of: (i) the amount which would otherwise be due pursuant to revenue interest payments terms; or (ii) $10.0 million.

Before December 31, 2028, if the sum of all payments under the RIFA paid to NovaQuest, does not equal or exceed $62.5 million, then the Company shall pay NovaQuest the difference of these two amounts by no later than March 1, 2029. If, by no later than December 31, 2030, the sum of all payments under the RIFA paid to NovaQuest does not equal or exceed $125.0 million, then the Company shall pay NovaQuest the difference of these two amounts by no later than March 1, 2031.

NovaQuest will retain this entitlement until it has reached the Payment Cap, at which point 100% of such revenue interest on future global net sales of Astellas will revert to the Company.

Over the course of the RIFA, the effective interest rate is affected by the amount and timing of drug product revenue and revenue from milestone payments recognized, the changes in the timing of forecasted drug product revenue and revenue from milestone payments, and the timing of the Company’s payments to NovaQuest. On a quarterly basis, the Company reassesses the expected total revenue and the timing of such revenue, recalculates the amortization of debt discount and transactions costs and effective interest rate, and adjusts the accounting prospectively as needed. The Company’s estimated effective annual interest rate was 15.59% as of September 30, 2024.

The following table summarizes the activities of the liability related to sale of future revenues for the nine months ended September 30, 2024:


	Nine Months Ended September 30, 2024
Liability related to sale of future revenues - beginning balance	$	57,067
Interest paid		(5,653	)
Interest expense recognized		5,768
Liability related to sale of future revenues - ending balance		57,182
Less: Current portion classified to accrued and other current liabilities		(332	)
Liability related to sale of future revenues, non-current	$	56,850

During the three and nine months ended September 30, 2024, the Company recognized, under Astellas Agreements, development revenue of $0.4 million and $1.0 million, respectively, and drug product revenue of $(0.3) million and $(0.7) million, respectively. See Note 2, Collaboration Agreements, License Agreement and Revenue, for details.

During the three and nine months ended September 30, 2024, the Company recognized the related interest expense of $2.0 million and $5.8 million, respectively. During the three and nine months ended September 30, 2023, the Company recognized the related interest expense of $2.1 million and $5.6 million, respectively. During the first quarter of 2024, the Company paid $5.7 million accrued interest.

Based on the current estimates of drug product revenue and revenue from milestone payments under the Astellas Agreements, and taking into the consideration of the terms discussed above, the Company anticipates reaching a Payment Cap up to $125.0 million by 2031.

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	$ 28,858			$ 12,740				$ 28,858		$ 12,740
Drug product revenue recognized	46,333				$ 40,134			152,877	$ 120,614
Other long-term liabilities	837			2,858				837		2,858
Astra Zeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty revenue recognized as drug product revenue								115,339
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	(262)				1,320			24,954	17,701
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	300							700
Drug Product Revenue, Net [Member] \| Europe [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,093				625			3,209	1,465
Drug Product Revenue, Net [Member] \| Europe [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized								5,600
Collaboration agreement payment								35,300
Burdened manufacturing costs				800
Drug Product Revenue, Net [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized						$ 14,400	$ 1,700
Drug Product Revenue, Net [Member] \| Japan [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	(1,355)				695			(3,926)	16,236
Accrued liabilities	3,600			1,200				3,600		1,200
Other long-term liabilities	600			700				600		700
Drug Product Revenue, Net [Member] \| API Shipment [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,400	$ 400	$ 2,200		700	$ 600
Bulk Drug Product [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue				17,700						17,700
Bulk Drug Product [Member] \| Europe [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized										38,700
Accrued liabilities	9,000			$ 38,600				9,000		$ 38,600
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	$ 1,100				$ 600			$ 3,200	$ 1,500

Variable Interest Entities

9 Months Ended

Sep. 30, 2024

Business Combinations [Abstract]

Variable Interest Entities

. Variable Interest Entities

Consolidated Variable Interest Entity - Fortis

On May 5, 2023 (the “Option Acquisition Date”), the Company entered into an exclusive option agreement to acquire Fortis Therapeutics, Inc. (“Fortis”) with its novel Phase 1 antibody-drug conjugate, 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 metastatic castration-resistant prostate cancer 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 the University of California, San Francisco, 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 University of California, San Francisco. If FibroGen chooses not to acquire Fortis, its exclusive license to FG-3246 would expire.

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. As part of the clinical development strategy, FibroGen will continue the work to develop a positron emission tomography (“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 September 30, 2024.

Fortis has authorized and issued common shares and Series A preferred shares. As of the Option Acquisition Date and September 30, 2024, 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 September 30, 2024, total assets and liabilities of Fortis were immaterial. For the three and nine months ended September 30, 2024, Fortis’ net income (losses) was immaterial.

Equity method investment - Unconsolidated VIE - Falikang

Falikang is a distribution entity jointly owned by AstraZeneca and FibroGen Beijing. FibroGen Beijing owns 51.1% of the outstanding shares of Falikang.

Pursuant to the guidance under ASC 810, the Company concluded that Falikang qualifies as a VIE. As Falikang is a distribution entity and AstraZeneca is the final decision maker for all the roxadustat commercialization activities, the Company lacks the power criterion, while AstraZeneca meets both the power and economic criteria under the ASC 810 to direct the activities of Falikang that most significantly impact its performance. Therefore, the Company is not the primary beneficiary of this VIE for accounting purposes. As a result, the Company accounts for its investment in Falikang under the equity method, and Falikang is not consolidated into the Company’s condensed consolidated financial statements. The Company records its total investments in Falikang as an equity method investment in an unconsolidated VIE in the condensed consolidated balance sheet. In addition, the Company recognizes its proportionate share of the reported profits or losses of Falikang as investment gain or loss in unconsolidated VIE in the condensed consolidated statement of operations and as an adjustment to its investment in Falikang in the condensed consolidated balance sheet. During the three months ended September 30, 2024, the Company received $2.2 million of dividend distribution from Falikang. The Company may provide shareholder loans to Falikang to meet necessary financial obligations as part of its operations. To date, there have been no such loans.

The Company’s equity method investment in Falikang was as follows (in thousands):


Entity	Ownership Percentage			Balance at December 31, 2023		Share of Net Income		Dividend Received			Currency Translation		Balance at September 30, 2024
Falikang		51.1	%	$	5,290	$	2,664	$	(2,230	)	$	82	$	5,806

Falikang is considered a related party to the Company. See Note 10, Related Party Transactions, for related disclosures.

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 121,874
Gross Unrealized Holding Gains	30
Gross Unrealized Holding Losses	(6)
Estimated Fair Value	121,898
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,988
Gross Unrealized Holding Gains	9
Gross Unrealized Holding Losses	(5)
Estimated Fair Value	13,992
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	52,273
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Estimated Fair Value	52,273
U.S. government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,783
Gross Unrealized Holding Gains	20
Gross Unrealized Holding Losses	0
Estimated Fair Value	45,803
Agency bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,830
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	(1)
Estimated Fair Value	$ 9,830

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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+ Details

- 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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Significant Accounting Policies - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($) Segment
Accounting Policy [Line Items]
Number of reportable segment \| Segment	1
Minimum [Member]
Accounting Policy [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts	$ 30
Debt Financing Agreement [Member] \| Minimum [Member]
Accounting Policy [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts	$ 30

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Cash and Cash Equivalents

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


	September 30, 2024		December 31, 2023
Cash	$	56,176	$	63,396
Commercial paper		25,631		36,016
Money market funds		49,196		12,288
U.S. government bonds		—		1,988
Total cash and cash equivalents	$	131,003	$	113,688

Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Investments

he Company’s investments consist primarily of available-for-sale debt investments, and the amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s investments by major investments type are summarized in the tables below (in thousands):


	December 31, 2023
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
Corporate bonds	$	13,988	$	9	$	(5	)	$	13,992
Commercial paper		52,273		—		—			52,273
U.S. government bonds		45,783		20		—			45,803
Agency bonds		9,830		1		(1	)		9,830
Total investments	$	121,874	$	30	$	(6	)	$	121,898

Summary of Available for Sale Securities in Unrealized Loss Position, Fair Value and Gross Unrealized Loss By Length of Time Security in Continual Unrealized Loss Position

The following table summarizes, for all available for sale securities in an unrealized loss position as of December 31, 2023, the fair value and gross unrealized loss by length of time the security has been in a continual unrealized loss position (in thousands):


	December 31, 2023
	Less than 12 Months					12 Months or More					Total
	Estimated Fair Value		Gross Unrealized Holding Losses			Estimated Fair Value		Gross Unrealized Holding Losses			Estimated Fair Value		Gross Unrealized Holding Losses
Corporate bonds	$	—	$	—		$	3,495	$	(5	)	$	3,495	$	(5	)
U.S. government bonds		4,984		—			—		—			4,984		—
Agency bonds		4,987		(1	)		—		—			4,987		(1	)
Total	$	9,971	$	(1	)	$	3,495	$	(5	)	$	13,466	$	(6	)

Schedule of Inventory

Inventories consisted of the following (in thousands):


	September 30, 2024		December 31, 2023
Raw materials	$	948	$	1,376
Work-in-progress		17,775		34,614
Finished goods		5,214		5,575
Total inventories	$	23,937	$	41,565

Schedule of Prepaid Expenses and Other Current Assets

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


	September 30, 2024		December 31, 2023
Contract assets	$	25,804	$	26,481
Deferred revenues from associated contracts		—		(26,481	)
Net contract assets		25,804		—
Insurance proceeds receivable for litigation settlement		28,500		28,500
Prepaid assets		3,062		6,644
Other current assets		3,193		6,711
Total prepaid expenses and other current assets	$	60,559	$	41,855

Schedule of Accrued and Other Current Liabilities

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


	September 30, 2024		December 31, 2023
Preclinical and clinical trial accruals	$	6,689	$	27,663
API and bulk drug product price true-up		12,592		50,978
Litigation settlement		28,500		28,500
Payroll and related accruals		6,144		20,267
Accrued restructuring charge		14,173		3,697
Inventory cost related		8,521		—
Accrued co-promotion expenses - current		53,714		10,309
Roxadustat profit share to AstraZeneca		—		7,084
Lease termination related		4,558		—
Value added taxes and other taxes		7,121		6,615
Professional services		4,396		7,103
Current portion of liability related to sale of future revenues		332		5,654
Other		4,401		5,021
Total accrued and other current liabilities	$	151,141	$	172,891

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (17,084)	$ (63,615)	$ (65,561)	$ (228,000)

- Definition

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

+ References

+ Details

Collaboration Agreements, License Agreement and Revenues - Summary of Amounts Recognized as Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue Recognition, Milestone Method [Line Items]
Total revenue	$ 46,333	$ 40,134	$ 152,877	$ 120,614
License Revenue [Member]
Revenue Recognition, Milestone Method [Line Items]
Total revenue	0	2,649	0	9,649
License Revenue [Member] \| Eluminex [Member]
Revenue Recognition, Milestone Method [Line Items]
Total revenue	0	0	0	7,000
Other Revenue - Patent Transfer [Member] \| Eluminex [Member]
Revenue Recognition, Milestone Method [Line Items]
Total revenue	0	500	0	500
Other Revenue - Contract Manufacturing [Member]
Revenue Recognition, Milestone Method [Line Items]
Total revenue	385	6,775	1,532	15,825
Other Revenue - Contract Manufacturing [Member] \| Eluminex [Member]
Revenue Recognition, Milestone Method [Line Items]
Total revenue	$ 0	$ 241	$ 116	$ 723

- Definition

+ References

+ Details

Liability Related to Sale of Future Revenues - Schedule of Activities of Liability Related to Sale of Future Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2024	Sep. 30, 2024
Liability Related to Sale of Future Royalties [Abstract]
Liability related to sale of future revenues - beginning balance	$ 57,067	$ 57,067
Interest paid	$ (5,700)	(5,653)
Interest expense recognized		5,768
Liability related to sale of future revenues - ending balance		57,182
Less: Current portion classified to accrued and other current liabilities		(332)
Liability related to sale of future revenues, non-current		$ 56,850

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) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Astellas Agreement [Member] \| Japan [Member] \| License Revenue [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	$ 100,300
Astellas Agreement [Member] \| Japan [Member] \| Co-development, information sharing & committee services [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	17,100
Astellas Agreement [Member] \| Europe [Member] \| License Revenue [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	619,000
Astellas Agreement [Member] \| Europe [Member] \| Co-development, information sharing & committee services [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	287,700
AstraZeneca Agreements [Member]
Disaggregation of Revenue [Line Items]
Deferred Revenue	146,967	$ 179,851
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member] \| License Revenue [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	344,500
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member] \| Co-development, information sharing & committee services [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	625,500
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member] \| China performance obligation [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	$ 458,100

Collaboration Agreements, License Agreement and Revenues - AstraZeneca U.S./RoW Agreement - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable from related parties	$ 29,030			$ 29,030		$ 12,553
Related cost of goods sold	$ 5,295		$ 4,243	$ 36,227	$ 13,441
AstraZeneca U.S./RoW Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cumulative catch-up net adjustment		$ 25,700
Related accounts receivable		26,000
Related accrued liabilities		11,500
Related cost of goods sold		$ 21,100

- Definition

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

+ References

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+ Details

Senior Secured Term Loan Facilities (Table)

9 Months Ended

Sep. 30, 2024

Debt Disclosure [Abstract]

Summary of Senior Secured Term Loan Facilities

The Company’s senior secured term loan facilities as of September 30, 2024 were as follows (in thousands):


	September 30, 2024
Principal of senior secured term loan facilities	$	75,000
Less: Unamortized issuance costs and transaction costs		(2,221	)
Senior secured term loan facilities, ending balance		72,779
Less: Current Portion classified to accrued and other current liabilities		—
Senior secured term loan facilities, non-current	$	72,779

- 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

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+ Details

Collaboration Agreements, License Agreement and Revenues

9 Months Ended

Sep. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Collaboration Agreements, License Agreement and Revenues

2. Collaboration Agreements, License Agreement and Revenues

Astellas Agreements

Astellas Japan Agreement

In June 2005, the Company entered into a collaboration agreement with Astellas Pharma Inc. (“Astellas”) for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Astellas Japan Agreement”). Under this agreement, Astellas agreed to pay license fees, other upfront consideration and various milestone payments, totaling $172.6 million. The Astellas Japan Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range of the list price published by Japan’s Ministry of Health, Labour and Welfare, adjusted for certain elements, after commercial launch.

The aggregate amount of consideration received through September 30, 2024 totaled $105.1 million, excluding drug product revenue that is discussed under the Drug Product Revenue, Net section below. Based on its current development plans for roxadustat in Japan, the Company does not expect to receive most or all of the additional potential milestones under the Astellas Japan Agreement.

Amounts recognized as license revenue and development revenue under the Astellas Japan Agreement were not material for the three and nine months ended September 30, 2024 and 2023.

There was no license revenue or development revenue resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods for the three months ended September 30, 2024 under the Astellas Japan Agreement. The Company does not expect material variable consideration from estimated future co-development billing beyond the development period in the transaction price related to the Astellas Japan Agreement.

In 2018, FibroGen and Astellas entered into an amendment to the Astellas Japan Agreement that allows Astellas to manufacture roxadustat drug product for commercialization in Japan (the “Astellas Japan Amendment”). The related drug product revenue is described under the Drug Product Revenue, Net section below.

Astellas Europe Agreement

In April 2006, the Company entered into a separate collaboration agreement with Astellas for the development and commercialization of roxadustat for the treatment of anemia in Europe, the Middle East, the Commonwealth of Independent States and South Africa (“Astellas Europe Agreement”). Under the terms of the Astellas Europe Agreement, Astellas agreed to pay license fees, other upfront consideration and various milestone payments, totaling $745.0 million. Under the Astellas Europe Agreement, Astellas committed to fund 50% of joint development costs for Europe and North America, and all territory-specific costs. The Astellas Europe Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range.

The aggregate amount of consideration received under the Astellas Europe Agreement through September 30, 2024 totaled $685.0 million, excluding drug product revenue that is discussed under the Drug Product Revenue, Net section below. Based on its current development plans for roxadustat in Europe, the Company does not expect to receive most or all of the additional potential milestones under the Astellas Europe Agreement.

Amounts recognized as license revenue and development revenue under the Astellas Europe Agreement were as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2024		2023		2024		2023
Astellas Europe Agreement	Development revenue	$	382	$	2,322	$	987	$	5,657

The transaction price related to consideration received through September 30, 2024 and accounts receivable has been allocated to each of the performance obligations under the Astellas Europe Agreement, including $619.0 million for license and $287.7 million for co-development.

There was no license revenue or development revenue resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods for three months ended September 30, 2024 under the Astellas Europe Agreement. The Company does not expect material variable consideration from estimated future co-development billing beyond the development period in the transaction price related to the Astellas Japan Agreement.

In 2021, the Company entered into an EU Supply Agreement with Astellas under the Astellas Europe Agreement (“Astellas EU Supply Agreement”) to define general forecast, order, supply and payment terms for Astellas to purchase roxadustat bulk drug product from FibroGen in support of commercial supplies. The related drug product revenue is described under the Drug Product Revenue, Net section below.

AstraZeneca Agreements

AstraZeneca U.S./Rest of World (“RoW”) Agreement

Effective July 30, 2013, the Company entered into a collaboration agreement with AstraZeneca AB (“AstraZeneca”) for the development and commercialization of roxadustat for the treatment of anemia in the U.S. and all other countries in the world, other than China, not previously licensed under the Astellas Europe and Astellas Japan Agreements (“AstraZeneca U.S./RoW Agreement”).

On February 23, 2024, the Company and AstraZeneca entered into an agreement to terminate the AstraZeneca U.S./RoW Agreement, effective as of February 25, 2024 (“AstraZeneca Termination and Transition Agreement”). Pursuant to the AstraZeneca Termination and Transition Agreement, AstraZeneca returns all of their non-China roxadustat rights to the Company, with the exception of South Korea, and provides certain assistance during a transition period. In addition, as a part of this AstraZeneca Termination and Transition Agreement, AstraZeneca will receive tiered mid-single digit royalties on FibroGen’s sales of roxadustat in the terminated territories, or thirty-five percent of all revenue FibroGen receives if it licenses or sells such rights to a third-party. Neither party incurred any early termination penalties.

The aggregate amount of consideration for milestone and upfront payments received under the AstraZeneca U.S./RoW Agreement through the termination totaled $439.0 million, excluding drug product revenue under the Master Supply Agreement with AstraZeneca under the AstraZeneca U.S./RoW Agreement (“AstraZeneca Master Supply Agreement”), entered in 2020, which is described under the Drug Product Revenue, Net section below. In addition, resulting from the AstraZeneca Termination and Transition Agreement, the Company and AstraZeneca settled the outstanding balances relating to past transactions under the AstraZeneca Master Supply Agreement. Accordingly, during the three months ended March 31, 2024, the Company accounted for the termination of the AstraZeneca U.S./RoW agreement as a contract modification under the Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”) and recorded a cumulative catch-up adjustment as described under the Drug Product Revenue, Net section below.

The Company’s collaboration agreement with AstraZeneca for roxadustat in China, as described below, remains in place.

AstraZeneca China Agreement

Effective July 30, 2013, the Company (through its subsidiaries affiliated with China) entered into a collaboration agreement with AstraZeneca for roxadustat for the treatment of anemia in China (“AstraZeneca China Agreement”). Under the terms of the AstraZeneca China Agreement, AstraZeneca agreed to pay upfront consideration and potential milestone payments, totaling $376.7 million. The AstraZeneca China Agreement is structured as a 50/50 profit or loss share (as defined), which was amended under the AstraZeneca China Amendment as defined and discussed below, and provides for joint development costs (including capital and equipment costs for construction of the manufacturing plant in China), to be shared equally during the development period.

The aggregate amount of such consideration received for milestone and upfront payments through September 30, 2024 totaled $77.2 million.

On September 18, 2023, the Company received the formal notice, from Beijing Medical Products Administration, of renewal of its right to continue to market roxadustat in China through 2028. The Company evaluated the regulatory milestone payment associated with this renewal under the AstraZeneca China Agreement and concluded that this milestone was achieved in the third quarter of 2023. Accordingly, the consideration of $4.0 million associated with this milestone was included in the transaction price in the third quarter of 2023 and allocated to performance obligations under the AstraZeneca U.S./RoW Agreement and the AstraZeneca China Agreement and was unbilled as of December 31, 2023, recorded as a contract asset and fully netted against the contract liabilities (deferred revenue) related to the AstraZeneca China Agreement. During the three months ended September 30, 2024, based on the arrangements under the settlement agreements entered in September 2024 between FibroGen China and AstraZeneca to settle certain historical items, the $4.0 million milestone was billed and included in the accounts receivable as of September 30, 2024.

AstraZeneca China Amendment

In July 2020, FibroGen China Anemia Holdings, Ltd., FibroGen (China) Medical Technology Development Co., Ltd. (“FibroGen Beijing”), FibroGen International (Hong Kong) Limited, and AstraZeneca entered into an amendment to the AstraZeneca China Agreement, relating to the development and commercialization of roxadustat in China (the “AstraZeneca China Amendment”). Under the AstraZeneca China Amendment, in 2020, FibroGen Beijing and AstraZeneca completed the establishment of a jointly owned entity, Beijing Falikang Pharmaceutical Co., Ltd. (“Falikang”), which performs roxadustat distribution, as well as conducts sales and marketing through AstraZeneca.

Substantially all direct roxadustat product sales to distributors in China are made by Falikang, while FibroGen Beijing continues to sell roxadustat product directly in limited areas in China. FibroGen Beijing manufactures and supplies commercial product to Falikang based on a gross transfer price, which is adjusted for the estimated profit share. The net product revenue from the sales to Falikang and the net product revenue from direct sales distributors in China are described under Product Revenue, Net section below.

Prior to the above-mentioned termination of the AstraZeneca U.S./RoW Agreement, the Company evaluated under the ASC 606 and accounted for the AstraZeneca U.S./RoW Agreement and the AstraZeneca China Agreement as a single arrangement with the presumption that two or more agreements executed with a single customer at or around the same time should be presumed to be a single arrangement. As a result of the termination of the AstraZeneca U.S./RoW Agreement, during the three months ended March 31, 2024, the Company recorded the final development revenue under the AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement.


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2024		2023		2024		2023
AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement	License revenue	$	—	$	2,649	$	—	$	2,649
	Development revenue	$	—	$	3,676	$	418	$	7,981

The transaction price related to consideration received and accounts receivable through the termination of the AstraZeneca U.S./RoW Agreement has been allocated to each of the performance obligations under the AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement, including $344.5 million for license, $625.5 million for co-development, information sharing and committee services, and $458.1 million for China performance obligation (with cumulative revenue of $311.1 million through September 30, 2024) that is recognized as product revenue, as described under Product Revenue, Net section below.

Product Revenue, Net

Product revenue, net from the sales of roxadustat commercial product in China was as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Direct Sales:
Gross revenue	$	4,355		$	3,186		$	12,186		$	9,853
Discounts and rebates		(363	)		(261	)		(1,130	)		(763	)
Sales returns		(3	)		2			(4	)		2
Direct sales revenue, net		3,989			2,927			11,052			9,092

Sales to Falikang:
Gross transaction price		53,696			42,294			146,608			118,696
Profit share		(23,973	)		(18,130	)		(64,393	)		(51,430	)
Net transaction price		29,723			24,164			82,215			67,266
Decrease in deferred revenue		12,498			2,299			33,124			1,081
Sales to Falikang revenue, net		42,221			26,463			115,339			68,347
Total product revenue, net	$	46,210		$	29,390		$	126,391		$	77,439

Direct Sales

Product revenue from direct roxadustat product sales to distributors in China is recognized in an amount that reflects the consideration that the Company expects to be entitled to in exchange for those products, net of various sales rebates and discounts. The total discounts and rebates were immaterial for the periods presented.

Due to the Company’s legal right to offset, at each balance sheet date, the rebates and discounts are presented as reductions to gross accounts receivable from the distributor, or as a current liability to the distributor to the extent that the total amount exceeds the gross accounts receivable or when the Company expects to settle the discount in cash. The Company’s legal right to offset is determined at the individual distributor level. The contract liabilities were included in accrued and other current liabilities in the condensed consolidated balance sheet and the rebates and discounts reflected as reductions to gross accounts receivable for direct sales were immaterial as of September 30, 2024 and December 31, 2023, respectively.

Sales to Falikang – China Performance Obligation

Substantially all direct roxadustat product sales to distributors in China are made by Falikang. FibroGen Beijing manufactures and supplies commercial product to Falikang. The net transfer price for FibroGen Beijing’s product sales to Falikang is based on a gross transaction price, which is adjusted to account for the 50/50 profit share for the period.

The roxadustat sales to Falikang marked the beginning of the Company’s China performance obligation under the Company’s agreements with AstraZeneca. Product revenue is based on the transaction price of the China performance obligation. Revenue is recognized when control of the product is transferred to Falikang, in an amount that reflects the allocation of the transaction price to the performance obligation satisfied during the reporting period, and is expected to continue through 2033, which reflects our best estimates. Any net transaction price in excess of the revenue recognized is added to the deferred balance to date and will be recognized in future periods as the performance obligation is satisfied.

Periodically, the Company updates its assumptions such as gross transaction price and profit share, performance period, total sales quantity and other inputs including foreign currency translation impact, among others. Following updates to its estimates, the Company recognized $12.5 million and $33.1 million from the previously deferred revenue of the China performance obligation for the three and nine months ended September 30, 2024, respectively. The product revenue recognized for the three months ended September 30, 2024 included an increase in revenue of $4.5 million resulting from changes to estimated variable consideration in the current period relating to performance obligation satisfied in previous periods. Comparatively, following updates to its estimates, the Company recognized $2.3 million and $1.1 million from the previously deferred revenue of the China performance obligation for the three and nine months ended September 30, 2023, respectively.

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, 2023			Additions			Recognized as Revenue		Currency Translation and Other			Balance at September 30, 2024
Product revenue - AstraZeneca China performance obligation - deferred revenue	$	(179,851	)	$	(82,185	)	$	115,339	$	(270	)	$	(146,967	)

Deferred revenue includes amounts allocated to the China performance obligation under the AstraZeneca arrangement as revenue recognition associated with this unit of accounting is tied to the commercial launch of the products within China and to when the control of the manufactured commercial products is transferred to AstraZeneca. Contract assets and liabilities related to rights and obligations in the same contract are recorded net on the condensed consolidated balance sheets. As of September 30, 2024, deferred revenue included $147.0 million related to China performance obligation.

As of September 30, 2024, approximately $22.1 million of the above deferred revenue related to the China unit of accounting was included in short-term deferred revenue, which represents the amount of deferred revenue associated with the China unit of accounting that is expected to be recognized within the next 12 months, associated with the commercial sales in China.

Due to the Company’s legal right to offset, at each balance sheet date, the rebates and discounts, mainly related to profit sharing, are presented as reductions to gross accounts receivable from Falikang, which was immaterial as of September 30, 2024 and was $3.0 million as of December 31, 2023.

Drug Product Revenue, Net


	Three Months Ended September 30,					Nine Months Ended September 30,
	2024			2023		2024			2023
Astellas Japan Agreement	$	(1,355	)	$	695	$	(3,926	)	$	16,236
Astellas Europe Agreement		1,093			625		3,209			1,465
AstraZeneca U.S./RoW Agreement		—			—		25,671			—
Drug product revenue, net	$	(262	)	$	1,320	$	24,954		$	17,701

Astellas Japan Agreement

The Company updates its estimate of variable consideration related to the API shipments fulfilled under the terms of Astellas Japan Amendment at each balance sheet date. As a result, the Company recorded a reduction to the drug product revenue of $1.4 million for the three months ended September 30, 2024. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, among others.

For the three months ended June 30, 2024, the Company updated its estimate of variable consideration related to the API shipments fulfilled under the terms of Astellas Japan Amendment, and accordingly recorded a reduction to the drug product revenue of $0.4 million. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect foreign exchange impacts and the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, among others.

For the three months ended March 31, 2024, the Company updated its estimate of variable consideration related to the API shipments fulfilled under the terms of Astellas Japan Amendment, and accordingly recorded a reduction to the drug product revenue of $2.2 million. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, and foreign exchange impacts, among others.

During the three months ended September 30, 2023, the Company updated its estimate of variable consideration related to the API shipments fulfilled under the terms of Astellas Japan Amendment, and accordingly recorded an adjustment to the drug product revenue of $0.7 million. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, and foreign exchange impacts, among others.

During the three months ended June 30, 2023, the Company fulfilled two shipment obligations under the terms of Astellas Japan Amendment and recognized related drug product revenue of $14.4 million in the same period. In addition, the Company updated its estimate of variable consideration related to the API shipments fulfilled under the terms of Astellas Japan Amendment, and accordingly recorded a reduction to the drug product revenue of $0.6 million. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, and foreign exchange impacts, among others.

During the three months ended March 31, 2023, the Company updated its estimate of variable consideration related to the API shipments fulfilled under the terms of Astellas Japan Amendment, and accordingly recorded an adjustment to the drug product revenue of $1.7 million. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, and estimated yield from the manufacture of bulk product tablets, among others.

As of September 30, 2024, the balances related to the API price true-up under the Astellas Japan Agreement were $3.6 million in accrued liabilities and $0.6 million in other long-term liabilities, representing the Company’s best estimate of the timing for these amounts to be paid. As of December 31, 2023, the balances related to the API price true-up under the Astellas Japan Agreement were $1.2 million in accrued liabilities and $0.7 million in other long-term liabilities.

Astellas Europe Agreement

The Company transferred bulk drug product for commercial purposes under the terms of the Astellas Europe Agreement and the Astellas EU Supply Agreement in the prior years. The Company recognized the related fully burdened manufacturing costs as drug product revenue in the respective periods and recorded the constrained transaction price in deferred revenue due to a high degree of uncertainty associated with the variable consideration for revenue recognition purposes. The Company updates its estimate of variable consideration related to the bulk drug product transferred in prior years at each balance sheet date.

During the fourth quarter of 2023, the Company transferred bulk drug product for commercial purposes under the terms of the Astellas Europe Agreement and the Astellas EU Supply Agreement, and recognized the related fully-burdened manufacturing costs of $0.8 million as drug product revenue, and recorded $17.7 million as deferred revenue due to a high degree of uncertainty associated with the variable consideration for revenue recognition purposes. In addition, the Company updated its estimate of variable consideration related to the bulk drug product transferred in prior years. Specifically, the change in estimated variable consideration was based on the bulk drug product held by Astellas at the period end, adjusted to reflect the changes in the estimated transfer price, forecast information, shelf-life estimates and other items. As a result, for the year ended December 31, 2023, the Company reclassified $38.7 million from the related deferred revenue to accrued liabilities. As of December 31, 2023, the related balance in accrued liabilities was $38.6 million. The Company further reclassified $5.6 million from the related deferred revenue to accrued liabilities and paid $35.3 million to Astellas during the nine months ended September 30, 2024. As of September 30, 2024, the balances related to the bulk drug product price true-up under the Astellas Europe Agreement and the Astellas EU Supply Agreement were $9.0 million in accrued liabilities, representing the Company’s best estimate that these amounts will be paid within the next 12 months.

The Company recognized royalty revenue of $1.1 million and $0.6 million as drug product revenue from the deferred revenue under the Astellas Europe Agreement during the three months ended September 30, 2024 and 2023, and $3.2 million and $1.5 million for the nine months ended September 30, 2024 and 2023, respectively. It is the Company’s best estimate that the remainder of the deferred revenue will be recognized as revenue when uncertainty is resolved, based on the performance of roxadustat product sales in the Astellas territory.

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, 2023			Recognized as Revenue		Reclassified to Accrued Liability / Accounts Payable		Balance at September 30, 2024
Drug product revenue - deferred revenue:
Astellas Europe Agreement	$	(16,925	)	$	3,210	$	5,605	$	(8,110	)

AstraZeneca U.S./RoW Agreement

As described under AstraZeneca Agreements section above, pursuant to the AstraZeneca Termination and Transition Agreement related to the AstraZeneca U.S./RoW Agreement, the Company and AstraZeneca settled the outstanding balances relating to past transactions under the AstraZeneca Master Supply Agreement. Accordingly, during the three months ended March 31, 2024, the Company accounted for the termination of the AstraZeneca U.S./RoW agreement as a contract modification under the ASC 606 and recorded a cumulative catch-up net adjustment of $25.7 million to the drug product revenue. The related accounts receivable of $26.0 million and the related accrued liabilities of $11.5 million as of March 31, 2024 were settled during the second quarter of 2024.

Corresponding to the drug product revenue, during the three months ended March 31, 2024, the Company recorded the related cost of goods sold of $21.1 million.

Eluminex Agreement

In July 2021, FibroGen exclusively licensed to Eluminex Biosciences (Suzhou) Limited (“Eluminex”) global rights to its investigational biosynthetic cornea derived from recombinant human collagen Type III.

Under the terms of the agreement with Eluminex, as amended and restated in January 2022, Eluminex made an $8.0 million upfront payment to FibroGen during the first quarter of 2022. In addition, FibroGen may receive up to a total of $64.0 million in future manufacturing, clinical, regulatory, and commercial milestone payments for the biosynthetic cornea program, as well as $36.0 million in commercial milestones for the first recombinant collagen III product that is not the biosynthetic cornea. FibroGen will also be eligible to receive mid-single-digit to low double-digit royalties based upon worldwide net sales of cornea products, and low single-digit to mid-single-digit royalties based upon worldwide net sales of other recombinant human collagen type III products that are not cornea products.

In April 2023, FibroGen and Eluminex entered into an Amended and Restated Exclusive License Agreement (“A&R Eluminex Agreement”) in order to add to the license rights to recombinant human collagen Type I (in addition to the rights to collagen Type III that were already licensed). The A&R Eluminex Agreement included additional total upfront payments of $1.5 million.

During the first quarter of 2023, the Company recognized a $3.0 million milestone payment based on Eluminex implanting a biosynthetic cornea in the first patient of its clinical trial in China, and a $3.0 million manufacturing related milestone payment. During the second quarter of 2023, the Company recognized a $1.0 million upfront payment under the A&R Eluminex Agreement. During the third quarter of 2023, the Company recognized a $0.5 million upfront payment related to patent transfer under the A&R Eluminex Agreement.

During the first quarter of 2022, FibroGen and Eluminex entered into a separate contract manufacturing agreement, under which the Company is responsible for supplying the cornea product at cost plus 10% of its product manufacturing costs until its manufacturing technology is fully transferred to Eluminex, which occurred by the end of 2023. The related contract manufacturing revenue was recorded as other revenue and included in development and other revenue in the condensed consolidated statement of operations. Such contract manufacturing activity was generally ceased during the first quarter of 2024.

Amounts recognized as revenue under the agreements with Eluminex were as follows for the three and nine months ended September 30, 2024 and 2023 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2024		2023		2024		2023
Eluminex	License revenue	$	—	$	—	$	—	$	7,000
	Other revenue - contract manufacturing		—		241		116		723
	Other revenue - patent transfer	$	—		500	$	—		500

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		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	19,147	16,448	18,460	13,786
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	15,274	11,293	14,295	10,022
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	3,409	4,596	3,679	3,208
ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	464	559	486	556

Variable Interest Entities - Equity Method Investment - Unconsolidated VIE - Summary of Equity Method Investment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Acquisition And Variable Interest Entity [Line Items]
Beginning balance			$ 5,290
Share of Net Income	$ 898	$ 677	2,664	$ 2,023
Ending balance	$ 5,806		$ 5,806
Beijing Falikang Pharmaceutical Co. Ltd [Member]
Acquisition And Variable Interest Entity [Line Items]
Ownership Percentage	51.10%		51.10%
Beginning balance			$ 5,290
Share of Net Income			2,664
Dividend Received			(2,230)
Currency Translation			82
Ending balance	$ 5,806		$ 5,806

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References + Details

- Definition

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

+ References + Details

Senior Secured Term Loan Facilities - Summary of Senior Secured Term Loan Facilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Senior secured term loan facilities, non-current	$ 72,779	$ 71,934
Senior Secured Term Loan Facilities [Member]
Debt Instrument [Line Items]
Principal of senior secured term loan facilities	75,000
Less: Unamortized issuance costs and transaction costs	(2,221)
Senior secured term loan facilities, ending balance	72,779
Less: Current Portion classified to accrued and other current liabilities	0
Senior secured term loan facilities, non-current	$ 72,779

- 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

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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

Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2024

Accounting Policies [Abstract]

Description of Operations

FibroGen, Inc. (“FibroGen” or the “Company”) is headquartered in San Francisco, California, with subsidiary offices in Beijing and Shanghai, People’s Republic of China (“China”). FibroGen is developing and commercializing a diversified pipeline of novel therapeutics that work at the frontier of cancer biology and anemia.

Roxadustat is an oral small molecule inhibitor of hypoxia-inducible factor prolyl hydroxylase activity. Roxadustat (爱瑞卓®, EVRENZOTM) is approved in China, Europe, Japan, and numerous other countries for the treatment of anemia in chronic kidney disease for patients who are on dialysis and not on dialysis. Roxadustat is in clinical development for chemotherapy-induced anemia in China.

FG-3246 is a first-in-class antibody-drug conjugate targeting a novel epitope on CD46 that is in development for metastatic castration-resistant prostate cancer and other cancer indications.

FibroGen also has a pipeline of preclinical product candidates, FG-3165 and FG-3175, to address unmet patient needs in oncology.

Basis of Presentation and Principles of Consolidation

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. For any VIE for which FibroGen is not the primary beneficiary, the Company uses the equity method of accounting.

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

Liquidity and Going Concern

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 United States (“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, 2023, filed on February 26, 2024.

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 repatriate additional cash from its China operations or raise additional capital in the U.S., within the next 12 months, the Company would not be able to comply with its debt covenants under its senior secured term loan facilities that requires a minimum balance of $30 million of unrestricted cash and cash equivalents to be held in accounts in the U.S. Upon an event of default, the Company’s senior secured term loan facilities would become immediately due and payable. The Company continues to evaluate measures to repatriate additional cash from its China operations. 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 determined that there is substantial doubt about the Company’s ability to continue as a going concern within 12 months after the date that the financial statements are issued.

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

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 net loss for each of the three and nine months ended September 30, 2024 and 2023. 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 September 30,				Nine Months Ended September 30,
	2024		2023		2024		2023
Employee stock options		15,274		11,293		14,295		10,022
RSUs, PRSUs and TSR awards		3,409		4,596		3,679		3,208
ESPP		464		559		486		556
		19,147		16,448		18,460		13,786

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 Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40), which 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 November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires all public entities, including public entities with a single reportable segment, to provide in interim and annual periods one or more measures of segment profit or loss used by the chief operating decision maker to allocate resources and assess performance. In addition, this guidance requires disclosures of significant segment expenses and other segment items as well as incremental qualitative disclosures. This guidance is effective for fiscal years beginning after December 15, 2023, and interim periods after December 15, 2024, with retrospective application required, and early adoption permitted. 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

Astellas Agreements

Astellas Japan Agreement

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Accounts receivable from related parties	$ 15,534	$ 6,079
Prepaid expenses and other current assets from a related party	24,785	0
Accounts payable to related party	2	0
Accrued and other current liabilities to related party	12,592	39,814
Deferred revenue current to related party	6,723	7,220
Deferred revenue non-current to related party	1,388	9,705
Due to related parties, noncurrent	$ 559	$ 656
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	100,770,000	98,770,000
Common stock, shares outstanding	100,770,000	98,770,000

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Cash	$ 56,176	$ 63,396
Commercial paper	25,631	36,016
Money market funds	49,196	12,288
U.S. government bonds	0	1,988
Total cash and cash equivalents	$ 131,003	$ 113,688

- 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

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue:
Total revenue	$ 46,333	$ 40,134	$ 152,877	$ 120,614
Operating costs and expenses:
Cost of goods sold	$ 5,295	$ 4,243	$ 36,227	$ 13,441
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	$ 21,708	$ 61,194	$ 94,206	$ 231,158
Selling, general and administrative	17,554	25,573	62,650	91,029
Restructuring charge	18,554	12,606	18,554	12,606
Total operating costs and expenses	63,111	103,616	211,637	348,234
Loss from operations	(16,778)	(63,482)	(58,760)	(227,620)
Interest and other, net
Interest expense	(4,994)	(5,022)	(14,774)	(10,464)
Interest income and other income (expenses), net	3,802	4,296	5,092	7,984
Total interest and other, net	(1,192)	(726)	(9,682)	(2,480)
Loss before income taxes	(17,970)	(64,208)	(68,442)	(230,100)
Provision for (benefit from) income taxes	12	84	(217)	(77)
Investment income in unconsolidated variable interest entity	898	677	2,664	2,023
Net loss	$ (17,084)	$ (63,615)	$ (65,561)	$ (228,000)
Net loss per share - basic	$ (0.17)	$ (0.65)	$ (0.66)	$ (2.35)
Net loss per share - diluted	$ (0.17)	$ (0.65)	$ (0.66)	$ (2.35)
Weighted average number of common shares used to calculate net loss per share:
Basic	100,515	98,245	99,780	96,901
Diluted	100,515	98,245	99,780	96,901
License Revenue [Member]
Revenue:
Total revenue	$ 0	$ 2,649	$ 0	$ 9,649
Development and Other Revenue [Member]
Revenue:
Total revenue	385	6,775	1,532	15,825
Product Revenue, Net [Member]
Revenue:
Total revenue	46,210	29,390	126,391	77,439
Drug Product Revenue, Net [Member]
Revenue:
Total revenue	$ (262)	$ 1,320	$ 24,954	$ 17,701

Variable Interest Entities - Equity Method Investment - Unconsolidated VIE - Additional Information (Detail) - Beijing Falikang Pharmaceutical Co Ltd $ in Millions	3 Months Ended
	Sep. 30, 2024 USD ($)
Acquisition And Variable Interest Entity [Line Items]
Dividend received	$ 2.2
Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] \| FibroGen Beijing [Member] \| AstraZenecaAB [Member]
Acquisition And Variable Interest Entity [Line Items]
Percentage of outstanding shares acquired	51.10%

Collaboration Agreements, License Agreement and Revenues - Astellas Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended				9 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 46,333,000	$ 40,134,000			$ 152,877,000	$ 120,614,000
Deferred Revenue			28,858,000				28,858,000		$ 12,740,000
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			(262,000)	1,320,000			24,954,000	17,701,000
License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			0	2,649,000			0	9,649,000
Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price, variable consideration from estimated future co-development billing							$ 0
Japan [Member] \| Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue					$ 14,400,000	$ 1,700,000
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
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
Percentage of joint development costs committed to fund	50.00%
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			382,000	$ 2,322,000			987,000	$ 5,657,000
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			$ 287,700,000				$ 287,700,000

Commitments and Contingencies - Additional Information (Detail) $ in Millions	2 Months Ended	9 Months Ended	32 Months Ended
	May 31, 2021 PutativeClassAction	Sep. 30, 2024 USD ($)	Apr. 03, 2024 ShareholderDerivative	Dec. 31, 2023 USD ($)	Oct. 17, 2023 USD ($)
Commitments And Contingencies [Line Items]
Operating lease liability		$ 2.0
Number of complaints filed	5		7
Litigation settlement amount				$ 28.5	$ 28.5
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations		1.0
Other Purchases [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations		6.0
Research and Preclinical Stage Development Programs [Member]
Commitments And Contingencies [Line Items]
Maximum future milestone payments		$ 697.9

Collaboration Agreements, License Agreement and Revenues - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation Of Revenue [Line Items]
Total revenue	$ 46,333	$ 40,134	$ 152,877	$ 120,614
Product Revenue, Net [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	46,210	29,390	126,391	77,439
Product Revenue, Net [Member] \| Direct Sales [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	4,355	3,186	12,186	9,853
Total revenue	3,989	2,927	11,052	9,092
Product Revenue, Net [Member] \| Direct Sales [Member] \| Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(363)	(261)	(1,130)	(763)
Product Revenue, Net [Member] \| Direct Sales [Member] \| Sales Returns [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(3)	2	(4)	2
Product Revenue, Net [Member] \| Sales To Falikang [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	42,221	26,463	115,339	68,347
Gross transaction price	53,696	42,294	146,608	118,696
Product Revenue, Net [Member] \| Sales To Falikang [Member] \| Profit Share [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(23,973)	(18,130)	(64,393)	(51,430)
Product Revenue, Net [Member] \| Sales To Falikang [Member] \| Net Transfer Price [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	29,723	24,164	82,215	67,266
Product Revenue, Net [Member] \| Sales To Falikang [Member] \| Decrease in deferred revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 12,498	$ 2,299	$ 33,124	$ 1,081

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair value of U.S. treasury notes and bills transfered from level 1 to level 2			$ 26,300,000
Transfers of assets from level 1 to 2	$ 0
Transfers of assets from level 2 to 1	0
Transfers of assets into level 3	0	$ 0
Transfers of assets out of level 3	$ 0	$ 0

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2024	Oct. 31, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
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	false
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		100,770,153

Related Party Transactions

9 Months Ended

Sep. 30, 2024

Related Party Transactions

10. Related Party Transactions

Astellas is an equity investor in the Company and is considered a related party. The Company recorded license and development revenue related to collaboration agreements with Astellas of $0.4 million and $2.4 million for the three months ended September 30, 2024 and 2023, and $1.0 million and $5.8 million for the nine months ended September 30, 2024 and 2023, respectively. In addition, the Company recorded drug product revenue from Astellas of $(0.3) million and $1.3 million for the three months ended September 30, 2024 and 2023, and $(0.7) million and $17.7 million for the nine months ended September 30, 2024 and 2023, respectively. See Note 2, Collaboration Agreements, License Agreement and Revenues, for details.

The Company’s expense related to collaboration agreements with Astellas was immaterial for each of the three and nine months ended September 30, 2024 and 2023.

As of September 30, 2024 and December 31, 2023, accounts receivable from Astellas were $0.2 million and $0.8 million, respectively.

As of September 30, 2024 and December 31, 2023, total deferred revenue from Astellas was $8.1 million and $16.9 million, respectively.

As of September 30, 2024, the amounts due to Astellas, included in accrued and other current liabilities, and other long-term liabilities, totaled $13.2 million. As of December 31, 2023, the amount due to Astellas, included in accrued and other current liabilities, and other long-term liabilities, totaled $40.5 million.

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. See the Equity method investment - Unconsolidated VIE - Falikang section of Note 4, Variable Interest Entities, for details.

The net product revenue from Falikang was $42.2 million and $26.5 million for the three months ended September 30, 2024 and 2023, and $115.3 million and $68.3 million for the nine months ended September 30, 2024 and 2023, respectively. See the Product Revenue, Net section in Note 2, Collaboration Agreements, License Agreement and Revenues, for details.

The investment income in Falikang was $0.9 million and $0.7 million for the three months ended September 30, 2024 and 2023 and $2.7 million and $2.0 million for the nine months ended September 30, 2024 and 2023, respectively. During the three months ended September 30, 2024, the Company received $2.2 million of dividend distribution from Falikang. As of September 30, 2024 and December 31, 2023, the Company’s equity method investment in Falikang was $5.8 million and $5.3 million, respectively. See the Equity method investment - Unconsolidated VIE - Falikang section of Note 4, Variable Interest Entities, for details. The other income from Falikang was immaterial for each of the three and nine months ended September 30, 2024 and 2023.

As of September 30, 2024 and December 31, 2023, accounts receivable, net, from Falikang, were $15.3 million and $5.2 million, respectively.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477968/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477968/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org/850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

+ Details

Balance Sheet Components

9 Months Ended

Sep. 30, 2024

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):


	September 30, 2024		December 31, 2023
Cash	$	56,176	$	63,396
Commercial paper		25,631		36,016
Money market funds		49,196		12,288
U.S. government bonds		—		1,988
Total cash and cash equivalents	$	131,003	$	113,688

At September 30, 2024 and December 31, 2023, a total of $51.0 million and $32.2 million of the Company’s cash and cash equivalents were held outside of the U.S. in its foreign subsidiaries to be used primarily for its China operations, respectively.

Investments

The Company did not have any short-term or long-term investments as of September 30, 2024. As of December 31, 2023, the Company’s investments consist primarily of available-for-sale debt investments, and the amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s investments by major investments type are summarized in the tables below (in thousands):


	December 31, 2023
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
Corporate bonds	$	13,988	$	9	$	(5	)	$	13,992
Commercial paper		52,273		—		—			52,273
U.S. government bonds		45,783		20		—			45,803
Agency bonds		9,830		1		(1	)		9,830
Total investments	$	121,874	$	30	$	(6	)	$	121,898


	December 31, 2023
	Less than 12 Months					12 Months or More					Total
	Estimated Fair Value		Gross Unrealized Holding Losses			Estimated Fair Value		Gross Unrealized Holding Losses			Estimated Fair Value		Gross Unrealized Holding Losses
Corporate bonds	$	—	$	—		$	3,495	$	(5	)	$	3,495	$	(5	)
U.S. government bonds		4,984		—			—		—			4,984		—
Agency bonds		4,987		(1	)		—		—			4,987		(1	)
Total	$	9,971	$	(1	)	$	3,495	$	(5	)	$	13,466	$	(6	)

The Company periodically assesses whether the unrealized losses on its available-for-sale investments were temporary. The Company considers factors such as the severity and the reason for the decline in value, the potential recovery period and its intent to sell. For debt securities, the Company also considers whether (i) it is more likely than not that the Company will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. Based on the results of its review, the Company did not recognize any impairment for its available-for-sale investments during the three and nine months ended September 30, 2024 and 2023.

Inventories

Inventories consisted of the following (in thousands):


	September 30, 2024		December 31, 2023
Raw materials	$	948	$	1,376
Work-in-progress		17,775		34,614
Finished goods		5,214		5,575
Total inventories	$	23,937	$	41,565

As described under Note 2, Collaboration Agreements, License Agreement and Revenues above, resulting from the AstraZeneca Termination and Transition Agreement related to the AstraZeneca U.S./RoW Agreement, the Company was reimbursed $12.6 million for work-in-progress inventory, which was written off and recognized as cost of goods sold during the three months ended March 31, 2024.

Prepaid Expenses and Other Current Assets

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


	September 30, 2024		December 31, 2023
Contract assets	$	25,804	$	26,481
Deferred revenues from associated contracts		—		(26,481	)
Net contract assets		25,804		—
Insurance proceeds receivable for litigation settlement		28,500		28,500
Prepaid assets		3,062		6,644
Other current assets		3,193		6,711
Total prepaid expenses and other current assets	$	60,559	$	41,855

Based on the arrangements under the settlement agreements entered in September 2024 between FibroGen China and AstraZeneca to settle certain historical items, the unbilled contract assets as of September 30, 2024 included $24.8 million of unbilled receivables from Falikang and $1.0 million of unbilled development revenue under the AstraZeneca China Amendment. Such amounts are no longer subject to right of offset under the settlement agreements.

The unbilled contract assets as of December 31, 2023 included $22.5 million of unbilled co-development revenue under the AstraZeneca China Amendment and the $4.0 million unbilled regulatory milestone payment under the AstraZeneca China Agreement, which were netted against the contract liabilities (deferred revenue) in the same contract. These amounts were billed during the three months ended September 30, 2024 under the above-mentioned settlement agreements.

As of each of September 30, 2024 and December 31, 2023, 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. See the Accrued and Other Current Liabilities section below, and the Legal Proceedings and Other Matters section in Note 11, Commitments and Contingencies, for details.

Accrued and Other Current Liabilities

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


	September 30, 2024		December 31, 2023
Preclinical and clinical trial accruals	$	6,689	$	27,663
API and bulk drug product price true-up		12,592		50,978
Litigation settlement		28,500		28,500
Payroll and related accruals		6,144		20,267
Accrued restructuring charge		14,173		3,697
Inventory cost related		8,521		—
Accrued co-promotion expenses - current		53,714		10,309
Roxadustat profit share to AstraZeneca		—		7,084
Lease termination related		4,558		—
Value added taxes and other taxes		7,121		6,615
Professional services		4,396		7,103
Current portion of liability related to sale of future revenues		332		5,654
Other		4,401		5,021
Total accrued and other current liabilities	$	151,141	$	172,891

The accrued liabilities of $12.6 million and $51.0 million for API and bulk drug product price true-up as of September 30, 2024 and December 31, 2023, respectively, resulted from changes in estimated variable consideration associated with the API shipments fulfilled under the terms of the Astellas Japan Amendment, the bulk drug product transferred under the terms of the Astellas Europe Agreement and the Astellas EU Supply Agreement, and the bulk drug product shipments to AstraZeneca under the terms of the AstraZeneca Master Supply Agreement. During the second quarter of 2024, the Company paid $35.3 million to Astellas and $11.5 million to AstraZeneca related to accrued amounts. See the Drug Product Revenue, Net section in Note 2, Collaboration Agreements, License Agreement and Revenues, for details.

As of September 30, 2024 and December 31, 2023, 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, as mentioned above. See the Legal Proceedings and Other Matters section in Note 11, Commitments and Contingencies, for details.

Responding to the reported results for pamrevlumab on July 30, 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%. As a result, the Company recorded a total of $18.6 million non-recurring restructuring charge during the three months ended September 30, 2024, primarily consisting of notice period and severance payments, accrued vacation, and employee benefits contributions. During the three months ended September 30, 2024, total cash payments under the reduction in force was $6.1 million. The remaining accrued restructuring charge was $14.2 million as of September 30, 2024 and will be substantially paid out by early 2025.

The Company recorded an accrued inventory related cost of $8.5 million as of September 30, 2024, as part of the cost of goods sold resulting from the AstraZeneca Termination and Transition Agreement, discussed under Note 2, Collaboration Agreements, License Agreement and Revenues.

As of September 30, 2024, the Company included $42.4 million of historical co-promotion balances due to AstraZeneca based on the arrangements under the above-mentioned settlement agreements entered in September 2024 between FibroGen China and AstraZeneca, as such amounts are no longer subject to right of offset.

Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2024

Accounting Policies [Abstract]

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


	Three Months Ended September 30,				Nine Months Ended September 30,
	2024		2023		2024		2023
Employee stock options		15,274		11,293		14,295		10,022
RSUs, PRSUs and TSR awards		3,409		4,596		3,679		3,208
ESPP		464		559		486		556
		19,147		16,448		18,460		13,786

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Contract assets	$ 25,804	$ 26,481
Deferred revenues from associated contracts	0	(26,481)
Net contract assets	25,804	0
Insurance proceeds receivable for litigation settlement	28,500	28,500
Prepaid assets	3,062	6,644
Other current assets	3,193	6,711
Total prepaid expenses and other current assets	$ 60,559	$ 41,855

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 Income (Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interests [Member] Nonredeemable [Member]	Noncontrolling Interests [Member] Redeemable [Member]
Balance at Dec. 31, 2022	$ (1,480)	$ 942	$ 1,541,019	$ (5,720)	$ (1,557,688)	$ 19,967	$ 0
Balance, Shares at Dec. 31, 2022		94,166,086
Net loss	$ (228,000)	$ 0	$ 0	$ 0	$ (228,000)	$ 0	$ 0
Consolidation of Fortis	520,000	0	0	0	0	520,000	21,480,000
Change in unrealized gain or loss on investments	$ 2,415	$ 0	$ 0	$ 2,415	$ 0	$ 0	$ 0
Foreign currency translation adjustments	(3,618)	0	0	(3,618)	0	0	0
Issuance of common stock under ATM Program	48,407	$ 24	48,383	0	0	0	0
Issuance of common stock under ATM Program shares		2,472,090
Shares issued from stock plans, net of payroll taxes paid	3,603	$ 17	3,586	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		1,700,947
Stock-based compensation	41,471	$ 0	41,471	0	0	0	0
Balance at Sep. 30, 2023	(136,682)	$ 983	1,634,459	(6,923)	(1,785,688)	20,487	21,480
Balance, Shares at Sep. 30, 2023		98,339,123
Balance at Jun. 30, 2023	(81,787)	$ 982	1,625,067	(6,250)	(1,722,073)	20,487	21,480
Balance, Shares at Jun. 30, 2023		98,204,243
Net loss	(63,615)	$ 0	0	0	(63,615)	0	0
Change in unrealized gain or loss on investments	360	0	0	360	0	0	0
Foreign currency translation adjustments	(1,033)	0	0	(1,033)	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(83)	$ 1	(84)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		134,880
Stock-based compensation	9,476	$ 0	9,476	0	0	0	0
Balance at Sep. 30, 2023	(136,682)	$ 983	1,634,459	(6,923)	(1,785,688)	20,487	21,480
Balance, Shares at Sep. 30, 2023		98,339,123
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		98,770,247
Net loss	(65,561)	$ 0	0	0	(65,561)	0	0
Change in unrealized gain or loss on investments	(24)	0	0	(24)	0	0	0
Foreign currency translation adjustments	1,271	0	0	1,271	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(224)	$ 20	(244)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		1,999,906
Stock-based compensation	25,037	$ 0	25,037	0	0	0	0
Balance at Sep. 30, 2024	(223,180)	$ 1,008	1,668,434	(5,628)	(1,907,481)	20,487	21,480
Balance, Shares at Sep. 30, 2024		100,770,153
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		100,399,786
Net loss	(17,084)	$ 0	0	0	(17,084)	0	0
Change in unrealized gain or loss on investments	2	0	0	2	0	0	0
Foreign currency translation adjustments	(1,821)	0	0	(1,821)	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(111)	$ 4	(115)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		370,367
Stock-based compensation	7,687	$ 0	7,687	0	0	0	0
Balance at Sep. 30, 2024	$ (223,180)	$ 1,008	$ 1,668,434	$ (5,628)	$ (1,907,481)	$ 20,487	$ 21,480
Balance, Shares at Sep. 30, 2024		100,770,153

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		$ 121,898
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		13,992
Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		52,273
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	$ 74,827	172,190
Fair Value, Measurements, Recurring [Member] \| Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	49,196	12,288
Fair Value, Measurements, Recurring [Member] \| Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		13,992
Fair Value, Measurements, Recurring [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	25,631	88,289
Fair Value, Measurements, Recurring [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		47,791
Fair Value, Measurements, Recurring [Member] \| Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		9,830
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	49,196	55,085
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	49,196	12,288
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		42,797
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	25,631	117,105
Fair Value, Measurements, Recurring [Member] \| 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
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		13,992
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	25,631	88,289
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,994
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		9,830
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Fair Value, Measurements, Recurring [Member] \| 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
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 0	0
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		$ 0

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Preclinical and clinical trial accruals	$ 6,689	$ 27,663
API and bulk drug product price true-up	12,592	50,978
Litigation settlement	28,500	28,500
Payroll and related accruals	6,144	20,267
Accrued restructuring charge	14,173	3,697
Inventory cost related	8,521
Accrued co-promotion expenses - current	53,714	10,309
Roxadustat profit share to AstraZeneca		7,084
Lease termination related	4,558
Value added taxes and other taxes	7,121	6,615
Professional services	4,396	7,103
Current portion of liability related to sale of future revenues	332	5,654
Other	4,401	5,021
Total accrued and other current liabilities	$ 151,141	$ 172,891

Leases - Additioinal Information (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Sep. 27, 2024	Sep. 30, 2024	Sep. 30, 2024	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Existence of Option to Terminate [true false]			true
Lessee, Operating Lease, Option to Terminate			As part of its continuing efforts to reduce operating expenses and preserve cash, on September 27, 2024, the Company entered into an Agreement for Termination of Lease and Voluntary Surrender of Premises (“Lease Termination Agreement”) with its landlord, ARE-San Francisco No.43 Owner, LLC (“ARE”) related to the Company’s operating lease of its corporate headquarters in San Francisco, California. The Lease Termination Agreement modifies the lease agreement dated as of September 22, 2006, as subsequently amended and accelerates the expiration date of the term of the Lease from 2028 to no later than December 31, 2024.
Lease termination settlement amount	$ 10,000
Lease termination settlement one time cash payment	8,300
Lease termination, remaining security deposit	$ 1,700
Gain on lease termination		$ 1,700
Operating lease right-of-use assets		2,093	$ 2,093	$ 68,093
Operating lease liability		2,000	2,000
Derecognized [Member]
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets		56,100	56,100
Operating lease liability		68,500	68,500
Shanghai and Beijing, China [Member]
Lessee, Lease, Description [Line Items]
Operating lease liability		$ 2,100	$ 2,100
Minimum [Member] \| Shanghai and Beijing, China [Member]
Lessee, Lease, Description [Line Items]
Lessee, operating lease, expiration period			2025
Maximum [Member] \| Shanghai and Beijing, China [Member]
Lessee, Lease, Description [Line Items]
Lessee, operating lease, expiration period			2027

Collaboration Agreements, License Agreement and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail)	9 Months Ended
	Sep. 30, 2024 USD ($)
Europe [Member] \| Astellas Agreement [Member]
Disaggregation of Revenue [Line Items]
Changes in revenue from changes to estimated variable consideration	$ 0
Europe [Member] \| Astellas Agreement [Member] \| License [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	619,000,000
Europe [Member] \| Astellas Agreement [Member] \| Co Development Information Sharing And Committee Services [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	287,700,000
U.S./RoW and China [Member]
Disaggregation of Revenue [Line Items]
Changes in revenue from changes to estimated variable consideration	0
U.S./RoW and China [Member] \| AstraZeneca Agreements [Member] \| License [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	344,500,000
U.S./RoW and China [Member] \| AstraZeneca Agreements [Member] \| Co Development Information Sharing And Committee Services [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	625,500,000
U.S./RoW and China [Member] \| AstraZeneca Agreements [Member] \| China Performance Obligation [Member]
Disaggregation of Revenue [Line Items]
Total Consideration	458,100,000
U.S./RoW and China [Member] \| AstraZeneca Agreements [Member] \| Product [Member]
Disaggregation of Revenue [Line Items]
Cumulative Revenue	$ 311,100,000

Collaboration Agreements, License Agreement and Revenues - AstraZeneca Agreements - Additional Information 1 (Detail) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended
	Jul. 30, 2013	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Sep. 18, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		$ 46,333			$ 40,134			$ 152,877	$ 120,614
Deferred Revenue		28,858						28,858		$ 12,740
Drug product revenue recognized		46,333			40,134			152,877	120,614
Product [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		46,210			29,390			126,391	77,439
Drug product revenue recognized		46,210			29,390			126,391	77,439
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		(262)			1,320			24,954	17,701
Drug product revenue recognized		(262)			1,320			24,954	17,701
Drug Product Revenue, Net [Member] \| API Shipment [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		1,400	$ 400	$ 2,200	700	$ 600
Drug product revenue recognized		1,400	$ 400	$ 2,200	700	600
Japan [Member] \| Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue						14,400	$ 1,700
Drug product revenue recognized						$ 14,400	$ 1,700
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Recognized as Revenue								115,339
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								77,200
Transaction price and allocated to performance obligations											$ 4,000
Contract asset		4,000						4,000
Direct Sales [Member] \| Product [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		3,989			2,927			11,052	9,092
Drug product revenue recognized		$ 3,989			$ 2,927			$ 11,052	$ 9,092

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 131,003,000	$ 113,688,000
Short-term investments	0	121,898,000
Accounts receivable, net ($15,534 and $6,079 from related parties)	29,030,000	12,553,000
Inventories	23,937,000	41,565,000
Prepaid expenses and other current assets ($24,785 and $0 from a related party)	60,559,000	41,855,000
Total current assets	244,529,000	331,559,000
Restricted time deposits	1,658,000	1,658,000
Property and equipment, net	7,603,000	13,126,000
Equity method investment in unconsolidated variable interest entity	5,806,000	5,290,000
Operating lease right-of-use assets	2,093,000	68,093,000
Other assets	2,732,000	3,803,000
Total assets	264,421,000	423,529,000
Current liabilities:
Accounts payable ($2 and $0 to a related party)	9,238,000	17,960,000
Accrued and other current liabilities ($12,592 and $39,814 to a related party)	151,141,000	172,891,000
Deferred revenue ($6,723 and $7,220 to related parties)	28,858,000	12,740,000
Operating lease liabilities, current	1,293,000	14,077,000
Total current liabilities	190,530,000	217,668,000
Product development obligations	18,199,000	17,763,000
Deferred revenue, net of current ($1,388 and $9,705 to a related party)	126,219,000	157,555,000
Operating lease liabilities, non-current	707,000	66,537,000
Senior secured term loan facilities, non-current	72,779,000	71,934,000
Liability related to sale of future revenues, non-current	56,850,000	51,413,000
Other long-term liabilities ($559 and $656 to a related party)	837,000	2,858,000
Total liabilities	466,121,000	585,728,000
Commitments and Contingencies
Redeemable non-controlling interests	21,480,000	21,480,000
Stockholders' deficit:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at September 30, 2024 and December 31, 2023
Common stock, $0.01 par value; 225,000 shares authorized at September 30, 2024 and December 31, 2023; 100,770 and 98,770 shares issued and outstanding at September 30, 2024 and December 31, 2023	1,008,000	988,000
Additional paid-in capital	1,668,434,000	1,643,641,000
Accumulated other comprehensive loss	(5,628,000)	(6,875,000)
Accumulated deficit	(1,907,481,000)	(1,841,920,000)
Total stockholders' deficit attributable to FibroGen	(243,667,000)	(204,166,000)
Nonredeemable non-controlling interests	20,487,000	20,487,000
Total deficit	(223,180,000)	(183,679,000)
Total liabilities, redeemable non-controlling interests and deficit	$ 264,421,000	$ 423,529,000

Collaboration Agreements, License Agreement and Revenues - Eluminex Agreement - Additional Information 2 (Detail) - Eluminex [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jul. 31, 2021	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2024	Dec. 31, 2023	Apr. 30, 2023
Revenue Recognition, Milestone Method [Line Items]
Aggregate consideration received for milestone and upfront payments	$ 8.0					$ 4.0	$ 4.0
Future manufacturing clinical regulatory and commercial milestone payments	64.0
Commercial milestone	$ 36.0
Additional upfront payments								$ 1.5
Upfront payment		$ 0.5	$ 1.0
Cornea Products [Member]
Revenue Recognition, Milestone Method [Line Items]
Percentage of product manufacturing costs until manufacturing technology fully transferred					10.00%
China [Member] \| Biosynthetic Cornea [Member]
Revenue Recognition, Milestone Method [Line Items]
Milestone Payments				$ 3.0
Manufacturing related milestone payments				$ 3.0

Collaboration Agreements, License Agreement and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 46,333	$ 40,134	$ 152,877	$ 120,614
Contract with Customer, Liability [Abstract]
Deferred revenue, net of current	126,219		126,219		$ 157,555
Net unbilled milestone and co-development revenue	25,804		25,804		0
Constrained for Future Recognition [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	12,500	2,300	33,100	1,100
Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	46,210	$ 29,390	126,391	$ 77,439
China [Member] \| Product Revenue, Net [Member]
Contract with Customer, Liability [Abstract]
Contract with customer liability increase decrease in revenue due to changes to estimated variable consideration	4,500
AstraZeneca Agreements [Member]
Contract with Customer, Liability [Abstract]
Deferred Revenue	146,967		146,967		179,851
Deferred revenue, net of current	147,000		147,000
Net unbilled milestone and co-development revenue	1,000		1,000		22,500
AstraZeneca Agreements [Member] \| China [Member]
Contract with Customer, Liability [Abstract]
Deferred Revenue	$ 22,100		$ 22,100
Beijing Falikang Pharmaceutical Co Ltd \| Product Revenue, Net [Member]
Contract with Customer, Liability [Abstract]
Reductions to gross accounts receivable					$ 3,000

Variable Interest Entities - Consolidated Variable Interest Entity - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended
	May 05, 2023	Mar. 31, 2024	Sep. 30, 2024
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

Leases

9 Months Ended

Sep. 30, 2024

Leases [Abstract]

Leases

3. Leases

As part of its continuing efforts to reduce operating expenses and preserve cash, on September 27, 2024, the Company entered into an Agreement for Termination of Lease and Voluntary Surrender of Premises (“Lease Termination Agreement”) with its landlord, ARE-San Francisco No.43 Owner, LLC (“ARE”) related to the Company’s operating lease of its corporate headquarters in San Francisco, California. The Lease Termination Agreement modifies the lease agreement dated as of September 22, 2006, as subsequently amended and accelerates the expiration date of the term of the Lease from 2028 to no later than December 31, 2024.

Pursuant to the Lease Termination Agreement, the Company paid ARE a total consideration of $10.0 million settlement amount, consisting of a $8.3 million, paid before September 30, 2024, of a one-time cash payment by FibroGen for past rent, FibroGen’s share of operating costs, taxes, insurance, utilities, and other costs and a lease modification payment; and a $1.7 million security deposit, in the form of a letter of credit, drawn in early October 2024. As of execution of this Lease Termination Agreement, FibroGen is not responsible for the payment of any further rent payments or operating costs, taxes, insurance, utilities, or any other scheduled monthly payments due under the lease to ARE.

The Company ceased the use of the underlying operating lease right-of-use asset by September 30, 2024. As a result, as of September 30, 2024, the Company derecognized the related operating lease right-of-use asset of $56.1 million and operating lease liabilities of $68.5 million, and recorded an approximately $1.7 million gain as credits to the selling, general and administrative expenses for the three months ended September 30, 2024.

The remaining operating leases of $2.1 million as of September 30, 2024 are mainly associated with the real estate leases for office spaces in Shanghai and Beijing, China, expiring between 2025 and 2027.

Balance Sheet Components - Additional Information (Detail) - USD ($)		3 Months Ended			9 Months Ended
	Jul. 30, 2024	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Jul. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents		$ 131,003,000			$ 131,003,000		$ 113,688,000
Impairment loss		0		$ 0	0
API and bulk drug product price true-up		12,592,000			12,592,000		50,978,000
Accrued inventory related cost		8,521,000			8,521,000
Accrued litigation settlement		28,500,000			28,500,000		28,500,000
Net unbilled co-development revenue		25,804,000			25,804,000		0
Litigation settlement receivable		28,500,000			28,500,000		28,500,000
Restructuring plan, expected reduction to workforce, percentage	75.00%
Restructuring plan, non-recurring charges		18,554,000		$ 12,606,000	18,554,000	$ 12,606,000
Cash payments for restructuring					6,100,000
Accrued restructuring charges		14,200,000			14,200,000
Short-term investments		0			0		121,898,000
Long-term investment		0			0
Eluminex Agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate consideration received for milestone and upfront payments		4,000,000			4,000,000		4,000,000	$ 8,000,000
AstraZeneca Agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Inventory write-down					12,600,000
Net unbilled co-development revenue		1,000,000			1,000,000		22,500,000
Payment to related parties			$ 11,500,000
Historical co-promotion balances		42,400,000			42,400,000
Astellas Agreement [Member]
Schedule of Available-for-sale Securities [Line Items]
Payment to related parties			$ 35,300,000
Falikang [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled receivables		24,800,000			24,800,000
Foreign subsidiaries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents		$ 51,000,000			$ 51,000,000		$ 32,200,000

Senior Secured Term Loan Facilities - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Apr. 29, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Interest expense		$ 2.9	$ 2.9	$ 8.7	$ 4.5
Accrued interest		0.4		0.4
Minimum [Member]
Debt Instrument [Line Items]
Unrestricted cash and cash equivalent balance required to maintain in accounts		30.0		$ 30.0
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. 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		$ 30.0		$ 30.0
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		$ 3.7		$ 3.7
Initial Term Loan [Member] \| Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Term loan	$ 75.0
Delayed Draw Term Loan [Member] \| Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Term loan	37.5
Delayed Draw Term Loan 2 \| Debt Financing Agreement [Member]
Debt Instrument [Line Items]
Term loan	$ 37.5

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2024

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):


	September 30, 2024
	Level 1		Level 2		Level 3		Total
Money market funds	$	49,196	$	—	$	—	$	49,196
Commercial paper		—		25,631		—		25,631
Total	$	49,196	$	25,631	$	—	$	74,827

	December 31, 2023
	Level 1		Level 2		Level 3		Total
Money market funds	$	12,288	$	—	$	—	$	12,288
Corporate bonds		—		13,992		—		13,992
Commercial paper		—		88,289		—		88,289
U.S. government bonds		42,797		4,994		—		47,791
Agency bonds		—		9,830		—		9,830
Total	$	55,085	$	117,105	$	—	$	172,190

Collaboration Agreements, License Agreement and Revenues - Roll-forward of Related Contract Liabilities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
AstraZeneca Agreements [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2023	$ (179,851)
Additions	(82,185)
Recognized as Revenue	115,339
Currency Translation and Other	(270)
Balance at September 30, 2024	(146,967)
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Europe [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2023	(16,925)
Reclassified to Accrued Liability	5,605
Recognized as Revenue	3,210
Balance at September 30, 2024	$ (8,110)

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Summary of Drug Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 46,333	$ 40,134			$ 152,877	$ 120,614
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	(262)	1,320			24,954	17,701
Drug Product Revenue, Net [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized			$ 14,400	$ 1,700
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	300				700
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	(1,355)	695			(3,926)	16,236
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,093	625			3,209	1,465
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			$ 25,671	$ 0

- Definition

+ References

+ Details

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities
Net loss	$ (65,561)	$ (228,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,312	7,653
Amortization of finance lease right-of-use assets	28	402
Net accretion of premium and discount on investments	(1,680)	(3,654)
Investment income in unconsolidated variable interest entity	(2,664)	(2,023)
Loss on disposal of property and equipment	2,445	1
Stock-based compensation	25,037	41,471
Acquired in-process research and development expenses	0	24,636
Non-cash interest expense related to sale of future revenues	0	5,636
Dividend received from unconsolidated variable interest entity	2,230	2,255
Impairment of investment	0	1,000
Realized loss on sales of available-for-sale securities	0	271
Changes in operating assets and liabilities:
Accounts receivable, net	(15,958)	(16,283)
Inventories	17,778	(1,519)
Prepaid expenses and other current assets	(18,181)	(27,393)
Operating lease right-of-use assets	66,011	8,447
Other assets	1,115	962
Accounts payable	(8,705)	(14,057)
Accrued and other liabilities	(17,112)	(50,246)
Operating lease liabilities, current	(12,796)	1,669
Deferred revenue	(15,218)	(36,930)
Accrued interest expense related to sale of future revenues	115	0
Accrued interest for finance lease liabilities	18	(22)
Operating lease liabilities, non-current	(65,830)	(9,447)
Other long-term liabilities	(917)	(1,529)
Net cash used in operating activities	(107,533)	(296,700)
Investing activities
Purchases of property and equipment	(125)	(2,268)
Proceeds from sale of property and equipment	840	0
Purchases of available-for-sale securities	(8,628)	(157,210)
Cash acquired from consolidation of Fortis	0	656
Proceeds from sales of available-for-sale securities	0	1,730
Proceeds from maturities of investments	132,183	300,507
Net cash provided by investing activities	124,270	143,415
Financing activities
Proceeds from senior secured term loan facilities, net of issuance costs	0	74,078
Cash paid for transaction costs for senior secured term loan facilities	0	(2,746)
Repayments of finance lease liabilities	(36)	(128)
Repayments of lease obligations	0	(302)
Cash paid for payroll taxes on restricted stock unit releases	(340)	0
Proceeds from issuance of common stock under ATM Program, net of commissions	0	48,407
Proceeds from issuance of common stock under employee stock plans	116	3,686
Net cash provided by (used in) financing activities	(260)	122,995
Effect of exchange rate change on cash and cash equivalents	838	(4,496)
Net increase (decrease) in cash and cash equivalents	17,315	(34,786)
Total cash and cash equivalents at beginning of period	113,688	155,700
Total cash and cash equivalents at end of period	$ 131,003	$ 120,914

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Accounts receivable from related parties	$ 29,030		$ 29,030		$ 12,553
Investment income	898	$ 677	2,664	$ 2,023
Equity method investments	5,806		5,806		5,290
Astellas [Member]
Related Party Transaction [Line Items]
Reduction of drug product revenue from related party	(300)	1,300	(700)	17,700
Due to related parties	13,200		13,200		40,500
Astellas [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	200		200		800
Deferred Revenue	8,100		8,100		16,900
Falikang [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	15,300		15,300		5,200
Investment income	900	700	2,700	2,000
Dividend received	2,200
Equity method investments	5,800		$ 5,800		$ 5,300
Percentage of outstanding shares owned			51.10%
Falikang [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenues	42,200	26,500	$ 115,300	68,300
License and Development [Member] \| Astellas [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenues	$ 400	$ 2,400	$ 1,000	$ 5,800

Variable Interest Entity (Tables)

9 Months Ended

Sep. 30, 2024

Business Combinations [Abstract]

Summary of Equity Method Investment

The Company’s equity method investment in Falikang was as follows (in thousands):


Entity	Ownership Percentage			Balance at December 31, 2023		Share of Net Income		Dividend Received			Currency Translation		Balance at September 30, 2024
Falikang		51.1	%	$	5,290	$	2,664	$	(2,230	)	$	82	$	5,806

Income Taxes

9 Months Ended

Sep. 30, 2024

Income Tax Disclosure [Abstract]

Income Taxes

9. Income Taxes

Provisions for (benefits from) income tax for the three and nine months ended September 30, 2024 and 2023 were primarily 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.

- Definition

The entire disclosure for income tax.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12

Reference 2: http://www.xbrl.org/2003/role/exampleRef
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-Section 55
-Paragraph 231
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482663/740-10-55-231

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12C

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477891/740-270-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.5.Q1)
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-URI https://asc.fasb.org/1943274/2147479360/740-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/740/tableOfContent

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482685/740-10-50-14

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482603/740-30-50-2

+ Details

Liability Related to Sale of Future Revenues (Tables)

9 Months Ended

Sep. 30, 2024

Schedule of Activities of Liability Related to Sale of Future Revenues

The following table summarizes the activities of the liability related to sale of future revenues for the nine months ended September 30, 2024:


	Nine Months Ended September 30, 2024
Liability related to sale of future revenues - beginning balance	$	57,067
Interest paid		(5,653	)
Interest expense recognized		5,768
Liability related to sale of future revenues - ending balance		57,182
Less: Current portion classified to accrued and other current liabilities		(332	)
Liability related to sale of future revenues, non-current	$	56,850

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - Astellas Agreement [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Collaboration services and other revenue from a related party	$ 385	$ 2,358	$ 997	$ 5,821
Product revenue from a related party	42,221	26,463	115,339	68,347
Drug product revenue from a related party	$ (262)	$ 1,320	$ (717)	$ 17,701

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
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

Senior Secured Term Loan Facilities

9 Months Ended

Sep. 30, 2024

Debt Disclosure [Abstract]

Senior Secured Term Loan Facilities

7. Senior Secured Term Loan Facilities

On April 29, 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 September 30, 2024, 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. 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 nine months ended September 30, 2024 and 2023. The Company recorded interest expense of $2.9 million and $8.7 million, respectively, for the three and nine months ended September 30, 2024, respectively. The Company recorded interest expense of $2.9 million and $4.5 million for the three and nine months ended September 30, 2023, respectively. As of September 30, 2024, 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 September 30, 2024, including maintaining a minimum balance of $30 million of unrestricted cash and cash equivalents held in accounts in the U.S.

The Company’s senior secured term loan facilities as of September 30, 2024 were as follows (in thousands):


	September 30, 2024
Principal of senior secured term loan facilities	$	75,000
Less: Unamortized issuance costs and transaction costs		(2,221	)
Senior secured term loan facilities, ending balance		72,779
Less: Current Portion classified to accrued and other current liabilities		—
Senior secured term loan facilities, non-current	$	72,779

- 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
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Significant Accounting Policies

9 Months Ended

Sep. 30, 2024

Accounting Policies [Abstract]

Significant Accounting Policies

1. Significant Accounting Policies

Description of Operations

FG-3246 is a first-in-class antibody-drug conjugate targeting a novel epitope on CD46 that is in development for metastatic castration-resistant prostate cancer and other cancer indications.

FibroGen also has a pipeline of preclinical product candidates, FG-3165 and FG-3175, to address unmet patient needs in oncology.

Basis of Presentation and Principles of Consolidation

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

Liquidity and Going Concern

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, 2023, filed on February 26, 2024.

Net Loss per Share


	Three Months Ended September 30,				Nine Months Ended September 30,
	2024		2023		2024		2023
Employee stock options		15,274		11,293		14,295		10,022
RSUs, PRSUs and TSR awards		3,409		4,596		3,679		3,208
ESPP		464		559		486		556
		19,147		16,448		18,460		13,786

Risks and Uncertainties

Recently Issued Accounting Guidance Not Yet Adopted