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Insider Trading Arrangements	9 Months Ended
Insider Trading Arrangements	Sep. 30, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Rule 10b5-1 Trading Plans On August 31, 2023, Christine Chung, Senior Vice President, China Operations of the Company, terminated a Rule 10b5-1 trading plan, which was previously adopted on March 7, 2023 and intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act. The plan provided for the potential sale of up to 125,000 shares of common stock held by Ms. Chung. Prior to its termination, Ms. Chung sold 12,500 shares under the plan. On July 12, 2023, Mark Eisner, then Chief Medical Officer of the Company, terminated a Rule 10b5-1 trading plan, which was previously adopted on March 2, 2023 and intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act. The plan provided for the potential sale of up to 107,260 shares of common stock held by Mr. Eisner. Prior to its termination, Mr. Eisner sold 0 shares under the plan. On August 31, 2023, Juan Graham, Chief Financial Officer of the Company, terminated a Rule 10b5-1 trading plan, which was previously adopted on August 26, 2022 and intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act. The plan provided for the potential sale of up to 29,911 shares of common stock held by Mr. Graham. Prior to its termination, Mr. Graham sold 7,929 shares under the plan. On September 22, 2023, Jeffrey Henderson, a member of the Company’s Board of Directors, terminated a Rule 10b5-1 trading plan, which was previously adopted on March 3, 2023 and intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act. The plan provided for the potential sale of up to 20,000 shares of common stock held by Mr. Henderson. Prior to its termination, Mr. Henderson sold 6,000 shares under the plan.
Christine Chung [Member]
Trading Arrangements, by Individual
Name	Christine Chung
Title	Senior Vice President
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 7, 2023
Rule 10b5-1 Arrangement Terminated	true
Termination Date	August 31, 2023
Aggregate Available	125,000
Mark Eisner [Member]
Trading Arrangements, by Individual
Name	Mark Eisner
Title	Chief Medical Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 2, 2023
Rule 10b5-1 Arrangement Terminated	true
Termination Date	July 12, 2023
Aggregate Available	107,260
Juan Graham [Member]
Trading Arrangements, by Individual
Name	Juan Graham
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	August 26, 2022
Rule 10b5-1 Arrangement Terminated	true
Termination Date	August 31, 2023
Aggregate Available	29,911
Jeffrey Henderson [Member]
Trading Arrangements, by Individual
Name	Jeffrey Henderson
Title	Board of Directors
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 3, 2023
Rule 10b5-1 Arrangement Terminated	true
Termination Date	September 22, 2023
Aggregate Available	20,000

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Investments [Abstract]
Raw materials	$ 1,179	$ 1,241
Work-in-progress	34,906	36,003
Finished goods	4,611	3,192
Total inventories	$ 40,696	$ 40,436

Collaboration Agreements, License Agreement and Revenues - Summary of Amounts Recognized as Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 40,134	$ 15,735	$ 120,614	$ 106,367
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	2,649	0	9,649	22,590
License Revenue [Member] \| Eluminex [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	7,000	0
Other Revenue - Patent Transfer [Member] \| Eluminex [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	500	0	500	0
Other Revenue - Contract Manufacturing [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	6,775	2,453	15,825	19,672
Other Revenue - Contract Manufacturing [Member] \| Eluminex [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 241	$ 460	$ 723	$ 1,502

- Definition

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

+ References

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

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

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

+ Details

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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 40,134	$ 15,735	$ 120,614	$ 106,367
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	2,649	0	9,649	22,590
Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	6,775	2,453	15,825	19,672
Astellas Agreement [Member] \| License Revenue [Member] \| Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	22,590
Astellas Agreement [Member] \| Development Revenue [Member] \| Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	36	45	164	156
Astellas Agreement [Member] \| Development Revenue [Member] \| Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	2,322	1,369	5,657	8,263
AstraZeneca Agreements [Member] \| License Revenue [Member] \| U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	2,649	0	2,649	0
AstraZeneca Agreements [Member] \| Development Revenue [Member] \| U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 3,676	$ 579	$ 7,981	$ 9,750

- Definition

+ References

+ Details

Collaboration Agreements, License Agreement and Revenues

9 Months Ended

Sep. 30, 2023

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, 2023 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 as follows for the three and nine months ended September 30, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
Astellas Japan Agreement	Development revenue	$	36	$	45	$	164	$	156

The transaction price related to consideration received through September 30, 2023 and accounts receivable has been allocated to each of the following performance obligations under the Astellas Japan Agreement (in thousands):


Astellas Japan Agreement	Total Consideration Through September 30, 2023
License	$	100,347
Development revenue		17,047
Total license and development revenue	$	117,394

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.

On March 21, 2022, EVRENZO® (roxadustat) was registered with the Russian Ministry of Health. The Company evaluated the regulatory milestone payment associated with the approval in Russia under the Astellas Europe Agreement and concluded that this milestone was achieved in the first quarter of 2022. Accordingly, the consideration of $25.0 million associated with this milestone was included in the transaction price and allocated to performance obligations under the Astellas Europe Agreement, all of which was recognized as revenue during the first quarter of 2022 from performance obligations satisfied.

The aggregate amount of consideration received under the Astellas Europe Agreement through September 30, 2023 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, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
Astellas Europe Agreement	License revenue	$	—	$	—	$	—	$	22,590
	Development revenue	$	2,322	$	1,369	$	5,657	$	8,263


Astellas Europe Agreement	Total Consideration Through September 30, 2023
License	$	618,975
Development revenue		285,922
Total license and development revenue	$	904,897

Under the Astellas Europe Agreement, Astellas has an option to purchase roxadustat bulk drug product in support of commercial supplies. During the first quarter of 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”). China is covered by a separate agreement with AstraZeneca described below. Under the terms of the AstraZeneca U.S./RoW Agreement, AstraZeneca agreed to pay upfront, non-contingent, non-refundable and time-based payments, and potential milestone payments, totaling $1.2 billion. AstraZeneca commits to pay the Company tiered royalty payments on AstraZeneca’s future net sales (as defined in the agreement) of roxadustat in the low 20% range. In addition, the Company is entitled to receive a transfer price for shipment of commercial product based on a percentage of AstraZeneca’s net sales (as defined in the agreement) in the low- to mid-single digit range.

The aggregate amount of consideration received under the AstraZeneca U.S./RoW Agreement through September 30, 2023 totaled $439.0 million, excluding drug product revenue that is discussed separately below. Based on its current development plans for roxadustat in the U.S., the Company does not expect to receive most or all of the additional potential milestones under the AstraZeneca U.S./RoW Agreement.

In 2020, the Company entered into a Master Supply Agreement with AstraZeneca under the AstraZeneca U.S./RoW Agreement (“AstraZeneca Master Supply Agreement”) to define general forecast, order, supply and payment terms for AstraZeneca 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 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 in 2020 as 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, 2023 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 and allocated to performance obligations under the AstraZeneca U.S./RoW Agreement and the AstraZeneca China Agreement, $3.5 million of which was recognized as revenue during the third quarter of 2023 from performance obligations satisfied or partially satisfied. As of September 30, 2023, the $4.0 million milestone was recorded as a contract asset and was fully netted against the contract liabilities (deferred revenue) related to the AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement.

AstraZeneca China Amendment

In July 2020, FibroGen China Anemia Holdings, Ltd., FibroGen (China) Medical Technology Development Co., Ltd. (“FibroGen Beijing”), and 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 one province 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.

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, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement	License revenue	$	2,649	$	—	$	2,649	$	—
	Development revenue	$	3,676	$	579	$	7,981	$	9,750


AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement	Cumulative Revenue Through September 30, 2023		Deferred Revenue at September 30, 2023			Total Consideration Through September 30, 2023
License	$	344,493	$	—		$	344,493
Co-development, information sharing & committee services		623,619		—			623,619
China performance obligation *		175,081		177,576			352,657
Total license and development revenue	$	1,143,193	$	177,576	**	$	1,320,769

* China performance obligation revenue is recognized as product revenue, as described under Product Revenue, Net section below.

** Contract assets and liabilities related to rights and obligations in the same contract are recorded net on the consolidated balance sheets. As of September 30, 2023, deferred revenue included $151.4 million related to the AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement, which represents the net of $177.6 million of deferred revenue presented above and a $26.2 million unbilled milestone and co-development revenue under the AstraZeneca China Amendment.

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, 2023 under the AstraZeneca U.S./RoW Agreement. The remainder of the transaction price related to the AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement includes $2.0 million of variable consideration from estimated future co-development billing and is expected to be recognized over the remaining development service period, except for amounts allocated to the China performance obligation. The amount allocated to the China performance obligation is expected to be recognized as the Company transfers control of the commercial drug product to Falikang, and is expected to continue through 2028, which reflects our best estimates.

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.

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, 2023 and 2022 (in thousands):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2023			2022			2023			2022
Direct Sales:
Gross revenue	$	3,186		$	2,610		$	9,853		$	8,972
Discounts and rebates		(261	)		(166	)		(763	)		(353	)
Sales returns		2			1			2			3
Direct sales revenue, net		2,927			2,445			9,092			8,622

Sales to Falikang:
Gross transaction price		42,294			32,510			118,696			83,517
Profit share		(18,130	)		(12,980	)		(51,430	)		(31,894	)
Net transaction price		24,164			19,530			67,266			51,623
Decrease (increase) in deferred revenue		2,299			(4,616	)		1,081			(750	)
Sales to Falikang revenue, net		26,463			14,914			68,347			50,873
Total product revenue, net	$	29,390		$	17,359		$	77,439		$	59,495

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 were immaterial as of September 30, 2023 and December 31, 2022, respectively. The rebates and discounts reflected as reductions to gross accounts receivable for direct sales were immaterial as of September 30, 2023 and December 31, 2022, 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 transfer 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. 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 total sales quantity, performance period, gross transaction price and profit share and other inputs including foreign currency translation impact, among others. Following updates to its estimates, the Company recognized $2.3 million and $1.1 million from the revenue of the China performance obligation during the three and nine months ended September 30, 2023, respectively. The product revenue resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied in previous periods was immaterial for the three months ended September 30, 2023.

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, 2022			Additions			Recognized as Revenue		Currency Translation and Other		Balance at September 30, 2023
Product revenue - AstraZeneca China performance obligation - deferred revenue	$	(175,646	)	$	(72,519	)	$	68,347	$	2,242	$	(177,576	)

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. As of September 30, 2023, approximately $28.0 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 $2.5 million and $0.5 million as of September 30, 2023 and December 31, 2022, respectively.

Drug Product Revenue, Net

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, 2023 and 2022 (in thousands):


	Three Months Ended September 30,					Nine Months Ended September 30,
	2023		2022			2023		2022
Astellas Japan Agreement	$	695	$	(4,313	)	$	16,236	$	3,297
Astellas Europe Agreement		625		236			1,465		1,313
Drug product revenue, net	$	1,320	$	(4,077	)	$	17,701	$	4,610

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 an adjustment to the drug product revenue of $0.7 million for the three months ended September 30, 2023. 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 for the three months ended June 30, 2023. 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.

During the three months ended March 31, 2022, the Company fulfilled a shipment obligation under the terms of Astellas Japan Amendment, and recognized related drug product revenue of $9.8 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 recorded a reduction to the drug product revenue of $2.2 million during the first quarter of 2022. 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, estimated cost to convert the API to bulk product tablets, and estimated yield from the manufacture of bulk product tablets, among others.

During the three months ended September 30, 2022, 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 $4.3 million. Specifically, the change in estimated variable consideration was based on the API held by Astellas at period end, adjusted to reflect foreign currency translation impact and the changes in the estimated bulk product strength mix intended to be manufactured by Astellas, among others.

As of September 30, 2023, the balances related to the API price true-up under the Astellas Japan Agreement were $0.6 million in accrued liabilities and $0.7 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, 2022, the related balance in accrued liabilities was $6.5 million.

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 2022, 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, the Company reclassified the related deferred revenue to accrued liabilities during the year ended December 31, 2022. As of December 31, 2022, the related balance was $57.4 million in accrued liabilities, which was paid to Astellas during the second quarter of 2023. Further for the nine months ended September 30, 2023, the Company reclassified $28.7 million from the related deferred revenue to accrued liabilities. As of September 30, 2023, the balances related to the bulk drug product price true-up under the Astellas Europe Agreement and the Astellas EU Supply Agreement were $28.6 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 $0.6 million and $1.5 million as drug product revenue from the deferred revenue under the Astellas Europe Agreement during the three and nine months ended September 30, 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, 2022			Additions		Recognized as Revenue		Reclassified to Accrued Liability / Accounts Payable		Balance at September 30, 2023
Drug product revenue - deferred revenue:
Astellas Europe Agreement	$	(40,303	)	$	—	$	1,465	$	28,685	$	(10,153	)

AstraZeneca U.S./RoW Agreement

There was no shipment of bulk drug product to AstraZeneca as commercial supply under the terms of the AstraZeneca Master Supply Agreement during the periods presented.

During the first quarter of 2022, the Company evaluated the current developments in the U.S. market, and updated its estimates of variable consideration associated with bulk drug product shipments to AstraZeneca in prior years as commercial supply. As a result, the Company reclassified $11.2 million from the related deferred revenue to accrued liabilities during the year ended December 31, 2022, which remained unchanged as of September 30, 2023 and December 31, 2022, representing the Company’s best estimate that this amount will be paid within the next 12 months.

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, Eluminex made an $8.0 million upfront payment to FibroGen during the first quarter of 2022, which was recognized as license revenue for the performance obligation satisfied during 2021. 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 three months ended September 30, 2023, the Company recognized a $0.5 million upfront payment related to patent transfer under the A&R Eluminex Agreement. During the three months ended June 30, 2023, the Company recognized a $1.0 million upfront payment. During the three months ended March 31, 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 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. The related contract manufacturing revenue was recorded as other revenue and included in development and other revenue in the condensed consolidated statement of operations.

Amounts recognized as revenue under the Eluminex were as follows for the three and nine months ended September 30, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
Eluminex	License revenue	$	—	$	—	$	7,000	$	—
	Other revenue - patent transfer		500		—		500		—
	Other revenue - contract manufacturing	$	241	$	460	$	723	$	1,502

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 130,545	$ 273,189
Gross Unrealized Holding Gains	5	5
Gross Unrealized Holding Losses	(124)	(2,538)
Estimated Fair Value	130,426	270,656
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,987	83,080
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(77)	(1,072)
Estimated Fair Value	11,910	82,008
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	55,859	57,381
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(1)	0
Estimated Fair Value	55,858	57,381
U.S. government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	57,734	112,547
Gross Unrealized Holding Gains	3	5
Gross Unrealized Holding Losses	(46)	(1,207)
Estimated Fair Value	57,691	111,345
Agency bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,965	11,690
Gross Unrealized Holding Gains	2	0
Gross Unrealized Holding Losses	0	(222)
Estimated Fair Value	$ 4,967	11,468
Foreign government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		5,007
Gross Unrealized Holding Gains		0
Gross Unrealized Holding Losses		(27)
Estimated Fair Value		4,980
Convertible promissory note [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,000
Gross Unrealized Holding Gains		0
Gross Unrealized Holding Losses		0
Estimated Fair Value		1,000
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,484
Gross Unrealized Holding Gains		0
Gross Unrealized Holding Losses		(10)
Estimated Fair Value		$ 2,474

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (63,615)	$ (91,650)	$ (228,000)	$ (227,479)

- 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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+ Details

Collaboration Agreements, License Agreement and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Europe [Member] \| Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Transaction price, variable consideration from estimated future co-development billing		$ 800,000
Changes in revenue from changes to estimated variable consideration	$ 0
U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Transaction price, variable consideration from estimated future co-development billing		$ 2,000,000
Changes in revenue from changes to estimated variable consideration	$ 0

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (63,615)	$ (91,650)	$ (228,000)	$ (227,479)
Other comprehensive income (loss):
Foreign currency translation adjustments	(1,033)	(436)	(3,618)	(28)
Available-for-sale investments:
Unrealized gain (loss) on investments, net of tax effect	360	20	2,415	(3,155)
Other comprehensive gain (loss), net of taxes	(673)	(416)	(1,203)	(3,183)
Comprehensive loss	$ (64,288)	$ (92,066)	$ (229,203)	$ (230,662)

- Definition

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

+ References

+ Details

- Definition

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

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-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-SubTopic 10
-Topic 220
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482739/220-10-55-15

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

+ Details

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Accounts receivable from related parties	$ 31,694		$ 31,694		$ 16,299
Investment income (loss)	677	$ 407	2,023	$ 1,293
Equity method investments	4,534		4,534		5,061
Astellas [Member]
Related Party Transaction [Line Items]
Drug product revenue from a related party	1,300	4,100	17,700	4,600
Due to related parties	29,800		29,800		63,900
Astellas [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	8,700		8,700		1,500
Deferred Revenue	10,200		10,200		40,300
Astellas [Member] \| License and Development [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenues	2,400	1,400	5,800	31,000
Falikang [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	14,200		14,200		10,500
Investment income (loss)	700	400	2,000	1,300
Dividend received	2,300
Equity method investments	4,500		$ 4,500		$ 5,100
Percentage of outstanding shares owned			51.10%
Falikang [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenues	$ 26,500	$ 14,900	$ 68,300	$ 50,900

Balance Sheet Components - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Jul. 14, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents		$ 120,914,000		$ 120,914,000		$ 155,700,000
Impairment loss		0	$ 0	0	$ 0
API and bulk drug product price true-up		40,325,000		40,325,000		75,055,000
Accrued litigation settlement		28,500,000		28,500,000
Restructuring plan, expected reduction to workforce, percentage	32.00%
Restructuring plan, non-recurring charges		12,606,000	$ 0	12,606,000	$ 0
Cash payments for restructuring		7,900,000
Accrued restructuring charges		4,700,000		4,700,000
Foreign subsidiaries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents		$ 60,100,000		$ 60,100,000		$ 92,500,000

Significant Accounting Policies

9 Months Ended

Sep. 30, 2023

Accounting Policies [Abstract]

Significant Accounting Policies

1. Significant Accounting Policies

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 a leading biopharmaceutical company discovering, developing and commercializing a pipeline of first-in-class therapeutics. The Company applies its pioneering expertise in hypoxia-inducible factor (“HIF”) biology, 2-oxoglutarate enzymology, and connective tissue growth factor to advance innovative medicines for the treatment of anemia and cancer.

Pamrevlumab, a human monoclonal antibody targeting connective tissue growth factor, is in Phase 3 clinical development for the treatment of locally advanced unresectable pancreatic cancer. Pamrevlumab is also in Phase 2/3 development for the treatment of metastatic pancreatic cancer. To date, the Company has retained exclusive worldwide rights for pamrevlumab.

Roxadustat is an oral small molecule inhibitor of HIF 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.

The Company has a pipeline of late-stage clinical programs as well as preclinical drug candidates at various stages of development that include both small molecules and biologics. FibroGen’s goal is to build a diversified pipeline with novel drugs that will address unmet patient needs with a refined focus 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.

The unaudited condensed consolidated financial statements and related disclosures have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) applicable to interim financial reporting and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X of the U.S. Securities and Exchange Commission (“SEC”) and, therefore, do not include all information and footnote disclosures normally included in the annual consolidated financial statements. The financial information included herein should be read in conjunction with the consolidated financial statements and related notes in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed on February 27, 2023.

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.

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 the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, filed on February 27, 2023, except for the updates to the following:

Asset Acquisition

The Company evaluates acquisitions of entities or assets to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen test to determine whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If this screen criteria is met, the transaction is accounted for as an asset acquisition. If not, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs which would meet the definition of a business. The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs.

In an asset acquisition, the cost allocated to acquire in-process research and development (“IPR&D”) with no alternative future use is charged to research and development expense at the acquisition date. The Company recognizes assets acquired and liabilities assumed in asset acquisitions, including contingent assets and liabilities, and non-controlling interests (“NCI”) in the acquired assets at their estimated fair values as of the date of acquisition.

An NCI represents the non-affiliated equity interest in the underlying entity or asset. The Company presents redeemable NCI in its consolidated statements of changes in equity within mezzanine equity. Nonredeemable NCI and redeemable NCI are initially recorded at their fair values. Subsequently, net loss in the underlying entity or asset is only allocated to nonredeemable NCI. Net income in the underlying entity or asset is allocated to nonredeemable NCI and redeemable NCI based on their respective stated rights.

Restructuring Charge

A restructuring charge is recognized when the liability is incurred and accrued in the period in which it is probable that the employees are entitled to the restructuring benefits and the amounts can be reasonably estimated. The restructuring liability accrued but not paid at the end of the reporting period is included in accrued and other current liabilities in the consolidated balance sheets.

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, 2023 and 2022. 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,
	2023		2022		2023		2022
Employee stock options		11,293		9,715		10,022		9,794
RSUs, PRSUs and TSR awards		4,596		1,978		3,208		2,066
ESPP		559		50		556		390
		16,448		11,743		13,786		12,250

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.

Exclusive License and Option to Acquire Fortis Therapeutics

9 Months Ended

Sep. 30, 2023

Business Combinations [Abstract]

Exclusive License and Option to Acquire Fortis Therapeutics

3. Exclusive License and Option to Acquire Fortis Therapeutics

On May 5, 2023 (the “Option Acquisition Date”), the Company entered into an exclusive option agreement to acquire Fortis Therapeutics (“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.

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 PET-based biomarker utilizing a radiolabeled version of the targeting antibody for patient selection.

Pursuant to the guidance under Accounting Standards Codification (“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, 2023. The transaction was accounted for as an asset acquisition under ASC 805, Business Combinations, as substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable IPR&D asset.

The fair value of the consideration transferred was zero. 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 UCSF, an upstream licensor to Fortis, development milestone fees and a single digit royalty on net sales of therapeutic or diagnostic products arising from the licensing arrangement between Fortis and UCSF. If FibroGen chooses not to acquire Fortis, its exclusive license to FG-3246 would expire.

Additionally, the Company is obligated to make four quarterly payments totaling $5.0 million to Fortis in support of its continued development obligations. The Company determined that these payments should not be included in the purchase consideration, as those payments are payable to Fortis rather than to its shareholders.

Fortis has authorized and issued common shares and Series A preferred shares. As of the Option Acquisition Date and September 30, 2023, the Company owned approximately 2% of Fortis’ Series A preferred shares, which was acquired previously and carried at zero cost. The 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 shares holders 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.

The following table represents the allocation of purchase consideration based on estimated fair values of the acquired assets (in thousands):


	Estimated Fair Value as of the Option Acquisition Date
Purchase consideration	$	—

Assets
Cash and cash equivalents		656
Prepaid expenses and other current assets		82
IPR&D assets		24,400
Total assets		25,138

Liabilities
Accounts payable		2,671
Accrued and other current liabilities		703
Total liabilities		3,374

Redeemable non-controlling interests		21,480
Nonredeemable non-controlling interests		520

Net identifiable assets, liabilities and non-controlling interests	$	(236	)

Loss on asset acquisition	$	(236	)

The Company used a third party valuation specialist to determine the fair value of the IPR&D assets using a risk-adjusted net present value discounted cash flow model (the “rNPV”) with the following key assumptions: (i) estimated cash flow forecasts of peak sales, sales penetration, remaining IPR&D related product development costs, and other related general and administrative costs; (ii) probabilities of technical success of future underlying Phase II and Phase III clinical trials and ensuing probability of regulatory approval related to the IPR&D assets; and (iii) estimate of a risk-adjusted discount rate of 16.5%. The acquired IPR&D assets were determined to have no alternative future use. Accordingly, the Company expensed fair value of the acquired IPR&D assets of $24.4 million as research and development expense in the condensed consolidated statements of operations for the nine months ended September 30, 2023.

The fair value of Fortis (enterprise value) and the fair value of nonredeemable NCI and redeemable NCI were determined based on the above-mentioned option exercise payment of $80.0 million and contingent payments up to $200.0 million, weighted with probability and expected timing of the underlying events consistent with the assumptions under the rNPV, and discounted by the Company’s estimated market level cost of debt.

As of September 30, 2023, total assets and liabilities of Fortis were immaterial. For the period from the Option Acquisition Date to September 30, 2023, Fortis’ net income (losses) was immaterial.

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 31,694	$ 16,299
Accounts receivable from related parties	22,916	12,088
Accrued and other current liabilities to related party	29,157	63,886
Deferred revenue current to related party	5,482	9,259
Deferred revenue non-current to related party	4,671	31,044
Due to related parties, noncurrent	$ 668	$ 0
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	98,339,000	94,166,000
Common stock, shares outstanding	98,339,000	94,166,000

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2023

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, 2023		December 31, 2022
Cash	$	70,982	$	135,819
Commercial paper		22,942		—
Money market funds		22,016		19,881
U.S. government bonds		4,974		—
Total cash and cash equivalents	$	120,914	$	155,700

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

The Company’s investments consist primarily of available-for-sale debt investments. 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):


	September 30, 2023
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
Corporate bonds	$	11,987	$	—	$	(77	)	$	11,910
Commercial paper		55,859		—		(1	)		55,858
U.S. government bonds		57,734		3		(46	)		57,691
Agency bonds		4,965		2		—			4,967
Total investments	$	130,545	$	5	$	(124	)	$	130,426

	December 31, 2022
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
Corporate bonds	$	83,080	$	—	$	(1,072	)	$	82,008
Commercial paper		57,381		—		—			57,381
U.S. government bonds		112,547		5		(1,207	)		111,345
Agency bonds		11,690		—		(222	)		11,468
Asset-backed securities		2,484		—		(10	)		2,474
Foreign government bonds		5,007		—		(27	)		4,980
Convertible promissory note		1,000		—		—			1,000
Total investments	$	273,189	$	5	$	(2,538	)	$	270,656

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, the fair value and gross unrealized loss by length of time the security has been in a continual unrealized loss position (in thousands):


	September 30, 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	$	2,483	$	(8	)	$	9,427	$	(69	)	$	11,910	$	(77	)
U.S. government bonds		17,360		(4	)		8,960		(42	)		26,320		(46	)
Commercial paper		3,481		(1	)		—		—			3,481		(1	)
Total	$	23,324	$	(13	)	$	18,387	$	(111	)	$	41,711	$	(124	)

	December 31, 2022
	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	$	6,738	$	(147	)	$	75,270	$	(925	)	$	82,008	$	(1,072	)
U.S. government bonds		22,326		(13	)		67,909		(1,194	)		90,235		(1,207	)
Agency bonds		—		—			11,468		(222	)		11,468		(222	)
Asset-backed securities		2,474		(10	)		—		—			2,474		(10	)
Foreign government bonds		—		—			4,980		(27	)		4,980		(27	)
Total	$	31,538	$	(170	)	$	159,627	$	(2,368	)	$	191,165	$	(2,538	)

Schedule of Inventory

Inventories consisted of the following (in thousands):


	September 30, 2023		December 31, 2022
Raw materials	$	1,179	$	1,241
Work-in-progress		34,906		36,003
Finished goods		4,611		3,192
Total inventories	$	40,696	$	40,436

Schedule of Accrued and Other Current Liabilities

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


	September 30, 2023		December 31, 2022
Preclinical and clinical trial accruals	$	34,670	$	57,780
API and bulk drug product price true-up		40,325		75,055
Litigation settlement		28,500		—
Payroll and related accruals		14,054		22,562
Accrued restructuring charge		4,694		—
Accrued co-promotion expenses - current		10,065		36,677
Roxadustat profit share to AstraZeneca		6,884		7,280
Property taxes and other taxes		7,950		7,691
Professional services		11,016		5,480
Current portion of liability related to sale of future revenues		5,860		—
Other		6,968		7,248
Total accrued and other current liabilities	$	170,986	$	219,773

Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2023 Segment
Accounting Policy [Line Items]
Number of reportable segment	1

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, 2021	$ 229,113	$ 929	$ 1,476,414	$ (4,163)	$ (1,264,034)	$ 19,967	$ 0
Balance, Shares at Dec. 31, 2021		92,880,533
Net loss	(227,479)	$ 0	0	0	(227,479)	0	0
Change in unrealized gain or loss on investments	(3,155)	0	0	(3,155)	0	0	0
Foreign currency translation adjustments	(28)	0	0	(28)	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(1,573)	$ 10	(1,583)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		1,055,807
Stock-based compensation	49,395	$ 0	49,395	0	0	0	0
Balance at Sep. 30, 2022	46,273	$ 939	1,524,226	(7,346)	(1,491,513)	19,967	0
Balance, Shares at Sep. 30, 2022		93,936,340
Balance at Jun. 30, 2022	123,747	$ 937	1,509,636	(6,930)	(1,399,863)	19,967	0
Balance, Shares at Jun. 30, 2022		93,733,034
Net loss	(91,650)	$ 0	0	0	(91,650)	0	0
Change in unrealized gain or loss on investments	20	0	0	20	0	0	0
Foreign currency translation adjustments	(436)	0	0	(436)	0	0	0
Shares issued from stock plans, net of payroll taxes paid	(993)	$ 2	(995)	0	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		203,306
Stock-based compensation	15,585	$ 0	15,585	0	0	0	0
Balance at Sep. 30, 2022	46,273	$ 939	1,524,226	(7,346)	(1,491,513)	19,967	0
Balance, Shares at Sep. 30, 2022		93,936,340
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 (Note 3)	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 Sheet Components

9 Months Ended

Sep. 30, 2023

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, 2023		December 31, 2022
Cash	$	70,982	$	135,819
Commercial paper		22,942		—
Money market funds		22,016		19,881
U.S. government bonds		4,974		—
Total cash and cash equivalents	$	120,914	$	155,700

At September 30, 2023 and December 31, 2022, a total of $60.1 million and $92.5 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


	September 30, 2023
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
Corporate bonds	$	11,987	$	—	$	(77	)	$	11,910
Commercial paper		55,859		—		(1	)		55,858
U.S. government bonds		57,734		3		(46	)		57,691
Agency bonds		4,965		2		—			4,967
Total investments	$	130,545	$	5	$	(124	)	$	130,426

	December 31, 2022
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
Corporate bonds	$	83,080	$	—	$	(1,072	)	$	82,008
Commercial paper		57,381		—		—			57,381
U.S. government bonds		112,547		5		(1,207	)		111,345
Agency bonds		11,690		—		(222	)		11,468
Asset-backed securities		2,484		—		(10	)		2,474
Foreign government bonds		5,007		—		(27	)		4,980
Convertible promissory note		1,000		—		—			1,000
Total investments	$	273,189	$	5	$	(2,538	)	$	270,656


	September 30, 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	$	2,483	$	(8	)	$	9,427	$	(69	)	$	11,910	$	(77	)
U.S. government bonds		17,360		(4	)		8,960		(42	)		26,320		(46	)
Commercial paper		3,481		(1	)		—		—			3,481		(1	)
Total	$	23,324	$	(13	)	$	18,387	$	(111	)	$	41,711	$	(124	)

	December 31, 2022
	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	$	6,738	$	(147	)	$	75,270	$	(925	)	$	82,008	$	(1,072	)
U.S. government bonds		22,326		(13	)		67,909		(1,194	)		90,235		(1,207	)
Agency bonds		—		—			11,468		(222	)		11,468		(222	)
Asset-backed securities		2,474		(10	)		—		—			2,474		(10	)
Foreign government bonds		—		—			4,980		(27	)		4,980		(27	)
Total	$	31,538	$	(170	)	$	159,627	$	(2,368	)	$	191,165	$	(2,538	)

At September 30, 2023, the available-for-sale investments had remaining contractual maturities of less than twelve months.

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 and 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, 2023 and 2022.

Inventories

Inventories consisted of the following (in thousands):


	September 30, 2023		December 31, 2022
Raw materials	$	1,179	$	1,241
Work-in-progress		34,906		36,003
Finished goods		4,611		3,192
Total inventories	$	40,696	$	40,436

Accrued and Other Current Liabilities

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


	September 30, 2023		December 31, 2022
Preclinical and clinical trial accruals	$	34,670	$	57,780
API and bulk drug product price true-up		40,325		75,055
Litigation settlement		28,500		—
Payroll and related accruals		14,054		22,562
Accrued restructuring charge		4,694		—
Accrued co-promotion expenses - current		10,065		36,677
Roxadustat profit share to AstraZeneca		6,884		7,280
Property taxes and other taxes		7,950		7,691
Professional services		11,016		5,480
Current portion of liability related to sale of future revenues		5,860		—
Other		6,968		7,248
Total accrued and other current liabilities	$	170,986	$	219,773

The accrued liabilities of $40.3 million for API and bulk drug product price true-up as of September 30, 2023 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. See the Drug Product Revenue, Net section in Note 2, Collaboration Agreements, License Agreement and Revenues, for details.

As of September 30, 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. 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. See the Legal Proceedings and Other Matters section in Note 12, Commitments and Contingencies, for details.

On July 14, 2023, the Company approved a restructuring plan (the “Plan”) to lower the Company’s operating expenses. The Plan included a reduction to the Company’s U.S. workforce of approximately 32%. As a result, the Company recorded a total of $12.6 million non-recurring restructuring charge during the three months ended September 30, 2023, primarily consisting of notice period and severance payments, accrued vacation, and employee benefits contributions. During the three months ended September 30, 2023, total cash payments under the Plan was $7.9 million. The remaining accrued restructuring charge was $4.7 million as of September 30, 2023 and will be substantially paid out by early 2024. The Plan is in connection with the Company’s efforts to streamline operations to align with the Company’s business goals.

Senior Secured Term Loan Facilities (Table)

9 Months Ended

Sep. 30, 2023

Debt Disclosure [Abstract]

Summary of Senior Secured Term Loan Facilities

The Company’s senior secured term loan facilities as of September 30, 2023 were as follows (in thousands):


	September 30, 2023
Principal of senior secured term loan facilities	$	75,000
Less: Unamortized issuance costs and transaction costs		(3,334	)
Senior secured term loan facilities, ending balance		71,666
Less: Current Portion classified to accrued and other current liabilities		—
Senior secured term loan facilities, non-current	$	71,666

- 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.

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+ Details

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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	16,448	11,743	13,786	12,250
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	11,293	9,715	10,022	9,794
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	4,596	1,978	3,208	2,066
ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of net loss per share	559	50	556	390

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2023	Oct. 31, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
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	Large 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	409 Illinois Street
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		98,340,219

Subsequent Event	9 Months Ended
Subsequent Event	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Event

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, 2023	Dec. 31, 2022
Astellas Agreement [Member] \| Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total Consideration	$ 117,394
Astellas Agreement [Member] \| Japan [Member] \| Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total Consideration	17,047
Astellas Agreement [Member] \| Japan [Member] \| License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total Consideration	100,347
Astellas Agreement [Member] \| Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total Consideration	904,897
Astellas Agreement [Member] \| Europe [Member] \| Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total Consideration	285,922
Astellas Agreement [Member] \| Europe [Member] \| License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total Consideration	618,975
AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	177,576	$ 175,646
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	1,143,193
Deferred Revenue	177,576
Total Consideration	1,320,769
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member] \| License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	344,493
Deferred Revenue	0
Total Consideration	344,493
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member] \| Co-development, information sharing & committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	623,619
Deferred Revenue	0
Total Consideration	623,619
AstraZeneca Agreements [Member] \| U.S./RoW and China [Member] \| China performance obligation [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	175,081
Deferred Revenue	177,576
Total Consideration	$ 352,657

Commitments and Contingencies - Additional Information (Detail) $ in Millions	2 Months Ended	9 Months Ended
	May 31, 2021 PutativeClassAction	Sep. 30, 2023 USD ($)	Oct. 17, 2023 USD ($)
Commitments And Contingencies [Line Items]
Operating lease liability		$ 81.9
Outstanding non-cancelable purchase obligations		37.8
Putative securities class action complaints filed \| PutativeClassAction	5
Litigation settlement amount		28.5	$ 28.5
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations		2.2
Manufacture and Supply of Pamrevlumab [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations		22.8
Other Purchases [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations		12.8
Research and Preclinical Stage Development Programs [Member]
Commitments And Contingencies [Line Items]
Maximum future milestone payments		$ 697.9

Senior Secured Term Loan Facilities

9 Months Ended

Sep. 30, 2023

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 have expired as of September 30, 2023.

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.

On May 8, 2023, the Company received $74.1 million, representing the Initial Term Loan of $75.0 million net of $0.9 million issuance costs. The 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 three and nine months ended September 30, 2023. 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, 2023, 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, 2023, including maintaining a minimum balance of $30 million of unrestricted cash and cash equivalents held in accounts in the U.S.

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, 2023, the fair values of such derivatives were negligible due to the low probability of the underlying events.

The Company’s senior secured term loan facilities as of September 30, 2023 were as follows (in thousands):


	September 30, 2023
Principal of senior secured term loan facilities	$	75,000
Less: Unamortized issuance costs and transaction costs		(3,334	)
Senior secured term loan facilities, ending balance		71,666
Less: Current Portion classified to accrued and other current liabilities		—
Senior secured term loan facilities, non-current	$	71,666

- 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.

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Senior Secured Term Loan Facilities - Summary of Senior Secured Term Loan Facilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	May 08, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Principal of senior secured term loan facilities		$ 74,100
Senior secured term loan facilities, non-current	$ 71,666		$ 0
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	(3,334)
Senior secured term loan facilities, ending balance	71,666
Less: Current Portion classified to accrued and other current liabilities	0
Senior secured term loan facilities, non-current	$ 71,666

- 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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-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69F

Reference 9: 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 14: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1F

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

- Definition

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

+ References + Details

At-the-Market Program

9 Months Ended

Sep. 30, 2023

Stockholders' Equity Note [Abstract]

At-the-Market Program

9. At-the-Market Program

On February 27, 2023, the Company entered into an Amended and Restated Equity Distribution Agreement (the “at-the-market agreement”) with Goldman Sachs & Co., LLC and BofA Securities, Inc. (each a “Sales Agent”), which amended and restated its Equity Distribution Agreement with Goldman Sachs & Co., LLC, dated August 8, 2022, to add BofA Securities, Inc. as an additional Sales Agent under that agreement. Under the at-the-market agreement, the Company may issue and sell, from time to time and through the Sales Agents, shares of its common stock having an aggregate offering price of up to $200.0 million (the “ATM Program”).

There was no transaction under the ATM Program for the three months ended September 30, 2023. For the nine months ended September 30, 2023, the Company sold 2,472,090 shares under the ATM Program, for proceeds of approximately $48.4 million, net of commissions to Sales Agents, at a weighted-average offering prices per share of $19.63.

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481004/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

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-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Section 50
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
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-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Liability Related to Sale of Future Revenues (Tables)

9 Months Ended

Sep. 30, 2023

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, 2023:


	Nine Months Ended September 30, 2023
Liability related to sale of future revenues - beginning balance	$	49,333
Interest expense recognized		5,636
Liability related to sale of future revenues - ending balance		54,969
Less: Current portion classified to accrued and other current liabilities		(5,860	)
Liability related to sale of future revenues, non-current	$	49,109

Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2023

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,
	2023		2022		2023		2022
Employee stock options		11,293		9,715		10,022		9,794
RSUs, PRSUs and TSR awards		4,596		1,978		3,208		2,066
ESPP		559		50		556		390
		16,448		11,743		13,786		12,250

Collaboration Agreements, License Agreement and Revenues (Tables)

9 Months Ended

Sep. 30, 2023

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, 2023 and 2022 (in thousands):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2023			2022			2023			2022
Direct Sales:
Gross revenue	$	3,186		$	2,610		$	9,853		$	8,972
Discounts and rebates		(261	)		(166	)		(763	)		(353	)
Sales returns		2			1			2			3
Direct sales revenue, net		2,927			2,445			9,092			8,622

Sales to Falikang:
Gross transaction price		42,294			32,510			118,696			83,517
Profit share		(18,130	)		(12,980	)		(51,430	)		(31,894	)
Net transaction price		24,164			19,530			67,266			51,623
Decrease (increase) in deferred revenue		2,299			(4,616	)		1,081			(750	)
Sales to Falikang revenue, net		26,463			14,914			68,347			50,873
Total product revenue, net	$	29,390		$	17,359		$	77,439		$	59,495

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, 2022			Additions			Recognized as Revenue		Currency Translation and Other		Balance at September 30, 2023
Product revenue - AstraZeneca China performance obligation - deferred revenue	$	(175,646	)	$	(72,519	)	$	68,347	$	2,242	$	(177,576	)

Schedule of Drug Product Revenue


	Three Months Ended September 30,					Nine Months Ended September 30,
	2023		2022			2023		2022
Astellas Japan Agreement	$	695	$	(4,313	)	$	16,236	$	3,297
Astellas Europe Agreement		625		236			1,465		1,313
Drug product revenue, net	$	1,320	$	(4,077	)	$	17,701	$	4,610

Summary of Amounts Recognized as Revenue

Amounts recognized as revenue under the Eluminex were as follows for the three and nine months ended September 30, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
Eluminex	License revenue	$	—	$	—	$	7,000	$	—
	Other revenue - patent transfer		500		—		500		—
	Other revenue - contract manufacturing	$	241	$	460	$	723	$	1,502

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, 2022			Additions		Recognized as Revenue		Reclassified to Accrued Liability / Accounts Payable		Balance at September 30, 2023
Drug product revenue - deferred revenue:
Astellas Europe Agreement	$	(40,303	)	$	—	$	1,465	$	28,685	$	(10,153	)

Japan [Member]

Summary of License Revenue and Development Revenue Recognized under Agreement

Amounts recognized as license revenue and development revenue under the Astellas Japan Agreement were as follows for the three and nine months ended September 30, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
Astellas Japan Agreement	Development revenue	$	36	$	45	$	164	$	156

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


Astellas Japan Agreement	Total Consideration Through September 30, 2023
License	$	100,347
Development revenue		17,047
Total license and development revenue	$	117,394

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, 2023 and 2022 (in thousands):


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
Astellas Europe Agreement	License revenue	$	—	$	—	$	—	$	22,590
	Development revenue	$	2,322	$	1,369	$	5,657	$	8,263

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


Astellas Europe Agreement	Total Consideration Through September 30, 2023
License	$	618,975
Development revenue		285,922
Total license and development revenue	$	904,897

U.S./RoW and China [Member]

Summary of License Revenue and Development Revenue Recognized under Agreement


		Three Months Ended September 30,				Nine Months Ended September 30,
Agreement	Performance Obligation	2023		2022		2023		2022
AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement	License revenue	$	2,649	$	—	$	2,649	$	—
	Development revenue	$	3,676	$	579	$	7,981	$	9,750

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


AstraZeneca U.S./RoW Agreement and AstraZeneca China Agreement	Cumulative Revenue Through September 30, 2023		Deferred Revenue at September 30, 2023			Total Consideration Through September 30, 2023
License	$	344,493	$	—		$	344,493
Co-development, information sharing & committee services		623,619		—			623,619
China performance obligation *		175,081		177,576			352,657
Total license and development revenue	$	1,143,193	$	177,576	**	$	1,320,769

* China performance obligation revenue is recognized as product revenue, as described under Product Revenue, Net section below.

Fair Value Measurements

9 Months Ended

Sep. 30, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

5. Fair Value Measurements

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


	September 30, 2023
	Level 1		Level 2		Level 3		Total
Money market funds	$	22,016	$	—	$	—	$	22,016
Corporate bonds		—		11,910		—		11,910
Commercial paper		—		78,800		—		78,800
U.S. government bonds		18,834		43,831		—		62,665
Agency bonds		—		4,967		—		4,967
Total	$	40,850	$	139,508	$	—	$	180,358

	December 31, 2022
	Level 1		Level 2		Level 3		Total
Money market funds	$	19,881	$	—	$	—	$	19,881
Corporate bonds		—		82,008		—		82,008
Commercial paper		—		57,381		—		57,381
U.S. government bonds		98,972		12,373		—		111,345
Agency bonds		—		11,468		—		11,468
Asset-backed securities		—		2,474		—		2,474
Foreign government bonds		—		4,980		—		4,980
Convertible promissory note		—		—		1,000		1,000
Total	$	118,853	$	170,684	$	1,000	$	290,537

The Company’s Level 2 investments are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar investments, issuer credit spreads, benchmark investments, prepayment/default projections based on historical data, and other observable inputs. During the three and nine months ended September 30, 2023, a total of $8.5 million and $15.4 million, respectively, of U.S. treasury notes and bills were transferred from Level 1 to Level 2 as such instruments were changed to off-the-run when they were issued before the most recent issue and were still outstanding at measurement day.

- Definition

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

+ References + Details

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating activities
Net loss	$ (228,000)	$ (227,479)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	7,653	7,503
Amortization of finance lease right-of-use assets	402	411
Net accretion of premium and discount on investments	(3,654)	1,842
Investment income in unconsolidated variable interest entity	(2,023)	(1,293)
Loss (gain) on disposal of property and equipment	1	(3)
Stock-based compensation	41,471	49,377
Acquired In-process Research and Development Expenses	24,636	0
Non-cash interest expense related to sale of future revenues	5,636	0
Dividend received from unconsolidated variable interest entity	2,255	0
Impairment of investment	1,000	0
Realized loss on sales of available-for-sale securities	271	5
Changes in operating assets and liabilities:
Accounts receivable, net	(16,283)	983
Inventories	(1,519)	(11,147)
Prepaid expenses and other current assets	(27,393)	8,265
Operating lease right-of-use assets	8,447	7,759
Other assets	962	823
Accounts payable	(14,057)	(5,120)
Accrued and other liabilities	(50,246)	87,167
Operating lease liabilities, current	1,669	715
Deferred revenue	(36,930)	4,509
Accrued interest for finance lease liabilities	(22)	(68)
Operating lease liabilities, non-current	(9,447)	(7,407)
Other long-term liabilities	(1,529)	(10,262)
Net cash used in operating activities	(296,700)	(93,420)
Investing activities
Purchases of property and equipment	(2,268)	(3,408)
Payment made for acquired in-process research and development asset	0	(35,000)
Proceeds from sale of property and equipment	0	8
Purchases of available-for-sale securities	(157,210)	(97,301)
Cash acquired from consolidation of Fortis	656	0
Proceeds from sales of available-for-sale securities	1,730	7,382
Proceeds from maturities of investments	300,507	216,342
Net cash provided by investing activities	143,415	88,023
Financing activities
Proceeds from senior secured term loan facilities, net of issuance costs	74,078	0
Cash paid for transaction costs for senior secured term loan facilities	(2,746)	0
Repayments of finance lease liabilities	(128)	(23)
Repayments of lease obligations	(302)	(302)
Cash paid for payroll taxes on restricted stock unit releases	0	(4,562)
Proceeds from issuance of common stock under ATM Program, net of commissions	48,407	0
Proceeds from issuance of common stock under employee stock plans	3,686	2,989
Net cash provided by (used in) financing activities	122,995	(1,898)
Effect of exchange rate change on cash and cash equivalents	(4,496)	(7,968)
Net decrease in cash and cash equivalents	(34,786)	(15,263)
Total cash and cash equivalents at beginning of period	155,700	171,223
Total cash and cash equivalents at end of period	$ 120,914	$ 155,960

Equity method investment - Variable Interest Entity - Summary of Equity Method Investment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Acquisition And Variable Interest Entity [Line Items]
Beginning balance			$ 5,061
Share of Net Income	$ 677	$ 407	2,023	$ 1,293
Ending balance	$ 4,534		$ 4,534
Beijing Falikang Pharmaceutical Co. Ltd [Member]
Acquisition And Variable Interest Entity [Line Items]
Ownership Percentage	51.10%		51.10%
Beginning balance			$ 5,061
Share of Net Income			2,023
Dividend Received			(2,255)
Currency Translation			(295)
Ending balance	$ 4,534		$ 4,534

Collaboration Agreements, License Agreement and Revenues - Roll-forward of Related Contract Liabilities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
AstraZeneca Agreements [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2022	$ (175,646)
Additions	(72,519)
Currency Translation and Other	2,242
Recognized as Revenue	68,347
Balance at June 30, 2023	(177,576)
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Europe [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2022	(40,303)
Additions	0
Reclassified to Accrued Liability	28,685
Recognized as Revenue	1,465
Balance at June 30, 2023	$ (10,153)

Collaboration Agreements, License Agreement and Revenues - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations Deferred Revenue (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue, net of current	$ 154,206	$ 185,722
AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	177,576	$ 175,646
AstraZeneca Agreements [Member] \| U.S./RoW [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue, net of current	151,400
Deferred Revenue	177,600
Net unbilled milestone and co-development revenue	$ 26,200

Exclusive License and Option to Acquire Fortis Therapeutics - Additional Information (Detail) - USD ($) $ in Thousands		9 Months Ended
	May 05, 2023	Sep. 30, 2023
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]
Purchase consideration	$ 0
Payment to options exercised	80,000
Contingent payment associated with business acquisition	200,000
Product development obligations	$ 5,000
Fair value of the acquired IPR&D assets		$ 24,400
Fortis Therapeutics [Member] \| Discounted Cash Flow [Member] \| Measurement Input Discount Rate [Member]
Business Acquisition [Line Items]
Discount rate applied		16.5

Exclusive License and Option to Acquire Fortis Therapeutics - Schedule of Allocation of Purchase Consideration Based on Estimated Fair Values of Acquired Assets (Details) - USD ($) $ in Thousands	May 05, 2023	Sep. 30, 2023	Dec. 31, 2022
Liabilities
Nonredeemable non-controlling interests		$ 20,487	$ 19,967
Fortis Therapeutics [Member]
Business Acquisition [Line Items]
Purchase consideration	$ 0
Assets
Cash and cash equivalents	656
Prepaid expenses and other current assets	82
IPR&D assets	24,400
Total assets	25,138
Liabilities
Accounts payable	2,671
Accrued and other current liabilities	703
Total liabilities	3,374
Redeemable non-controlling interests	21,480
Nonredeemable non-controlling interests	520
Net identifiable assets, liabilities and non-controlling interests	(236)
Loss on asset acquisition	$ (236)

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 120,914	$ 155,700
Short-term investments	130,426	266,308
Accounts receivable, net ($22,916 and $12,088 from related parties)	31,694	16,299
Inventories	40,696	40,436
Prepaid expenses and other current assets	40,378	14,083
Total current assets	364,108	492,826
Restricted time deposits	2,072	2,072
Long-term investments	0	4,348
Property and equipment, net	14,512	20,605
Equity method investment in unconsolidated variable interest entity	4,534	5,061
Operating lease right-of-use assets	71,248	79,893
Other assets	3,952	5,282
Total assets	460,426	610,087
Current liabilities:
Accounts payable	19,220	30,758
Accrued and other current liabilities ($29,157 and $63,886 to a related party)	170,986	219,773
Deferred revenue ($5,482 and $9,259 to related parties)	7,325	12,739
Operating lease liabilities, current	11,884	10,292
Total current liabilities	209,415	273,562
Product development obligations	16,942	16,917
Deferred revenue, net of current	154,206	185,722
Operating lease liabilities, non-current	70,035	79,593
Senior secured term loan facilities, non-current	71,666	0
Liability related to sale of future revenues, non-current	49,109	49,333
Other long-term liabilities ($668 and $0 to a related party)	4,255	6,440
Total liabilities	575,628	611,567
Commitments and Contingencies (Note 12)
Redeemable non-controlling interests	21,480	0
Stockholders' deficit:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at September 30, 2023 and December 31, 2022
Common stock, $0.01 par value; 225,000 shares authorized at September 30, 2023 and December 31, 2022; 98,339 and 94,166 shares issued and outstanding at September 30, 2023 and December 31, 2022	983	942
Additional paid-in capital	1,634,459	1,541,019
Accumulated other comprehensive loss	(6,923)	(5,720)
Accumulated deficit	(1,785,688)	(1,557,688)
Total stockholders' deficit attributable to FibroGen	(157,169)	(21,447)
Nonredeemable non-controlling interests	20,487	19,967
Total deficit	(136,682)	(1,480)
Total liabilities, redeemable non-controlling interests and deficit	$ 460,426	$ 610,087

Collaboration Agreements, License Agreement and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 40,134	$ 15,735	$ 120,614	$ 106,367
Constrained for Future Recognition [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	2,300		1,100
Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	29,390	$ 17,359	77,439	$ 59,495
AstraZeneca Agreements [Member]
Contract with Customer, Liability [Abstract]
Deferred Revenue	177,576		177,576		$ 175,646
AstraZeneca Agreements [Member] \| China [Member]
Contract with Customer, Liability [Abstract]
Deferred Revenue	28,000		28,000
Beijing Falikang Pharmaceutical Co Ltd \| Product Revenue, Net [Member]
Contract with Customer, Liability [Abstract]
Reductions to gross accounts receivable	$ 2,500		$ 2,500		$ 500

Related Party Transactions

9 Months Ended

Sep. 30, 2023

Related Party Transactions

11. 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 $2.4 million and $1.4 million for the three months ended September 30, 2023 and 2022, and $5.8 million and $31.0 million for the nine months ended September 30, 2023 and 2022, respectively. The Company also recorded drug product revenue from Astellas of $1.3 million and $(4.1) million for the three months ended September 30, 2023 and 2022, and $17.7 million and $4.6 million for the nine months ended September 30, 2023 and 2022, 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, 2023 and 2022.

As of September 30, 2023 and December 31, 2022, accounts receivable from Astellas were $8.7 million and $1.5 million, respectively.

As of September 30, 2023 and December 31, 2022, total deferred revenue from Astellas was $10.2 million and $40.3 million, respectively.

As of September 30, 2023, the amounts due to Astellas, included in accrued and other current liabilities, and other long-term liabilities, totaled $29.8 million. As of December 31, 2022, the amount due to Astellas, included in accrued and other current liabilities, was $63.9 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 Note 4, Equity method investment - Variable Interest Entity, for details.

The net product revenue from Falikang was $26.5 million and $14.9 million for the three months ended September 30, 2023 and 2022, and $68.3 million and $50.9 million for the nine months ended September 30, 2023 and 2022, respectively. See the Product Revenue, Net section in Note 2, Collaboration Agreements, License Agreement and Revenues, for details.

The investment income in Falikang was $0.7 million and $0.4 million for the three months ended September 30, 2023 and 2022, and $2.0 million and $1.3 million for the nine months ended September 30, 2023 and 2022, respectively. During the three months ended September 30, 2023, the Company received $2.3 million of dividend distribution from Falikang. As of September 30, 2023 and December 31, 2022, the Company’s equity method investment in Falikang was $4.5 million and $5.1 million, respectively. See Note 4, Equity method investment - Variable Interest Entity, for details. The other income from Falikang was immaterial for each of the three and nine months ended September 30, 2023 and 2022.

As of September 30, 2023 and December 31, 2022, accounts receivable, net, from Falikang, were $14.2 million and $10.5 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
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-Name Accounting Standards Codification
-Section 50
-Paragraph 5
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-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
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
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-Paragraph 2
-Subparagraph (e)
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-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

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

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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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
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-Name Accounting Standards Codification
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-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147483575/946-220-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
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-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
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-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Liability Related to Sale of Future Revenues - Schedule of Activities of Liability Related to Sale of Future Revenues (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Liability Related to Sale of Future Royalties [Abstract]
Liability related to sale of future revenues - beginning balance	$ 49,333
Interest expense recognized	5,636	$ 0
Liability related to sale of future revenues - ending balance	54,969
Less: Current portion classified to accrued and other current liabilities	(5,860)
Liability related to sale of future revenues, non-current	$ 49,109

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - Astellas Agreement [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
License and milestone revenue from a related party	$ 0	$ 0	$ 0	$ 22,590
Collaboration services and other revenue from a related party	2,358	1,414	5,821	8,419
Product revenue from a related party	$ 26,463	$ 14,914	$ 68,347	$ 50,873

Income Taxes

9 Months Ended

Sep. 30, 2023

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

Provisions for (benefits from) income tax for the three and nine months ended September 30, 2023 and 2022 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 taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: 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 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 2
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-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-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 - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended
	Nov. 04, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		$ 40,134,000	$ 15,735,000	$ 120,614,000	$ 106,367,000
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				16.07%
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		29,390,000	17,359,000	$ 77,439,000	59,495,000
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		2,649,000	0	9,649,000	22,590,000
Other Revenue - Contract Manufacturing [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		6,775,000	2,453,000	15,825,000	19,672,000
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
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		2,400,000		5,800,000
Drug Product Revenue [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		1,320,000	$ (4,077,000)	17,701,000	$ 4,610,000
Drug Product Revenue [Member] \| Astellas Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		1,300,000		17,700,000
Non-cash interest expense related to drug product revenue		$ 2,100,000		$ 5,600,000

Equity method investment - Variable Interest Entity - Additional Information (Detail) - Beijing Falikang Pharmaceutical Co Ltd $ in Millions	3 Months Ended
	Sep. 30, 2023 USD ($)
Acquisition And Variable Interest Entity [Line Items]
Dividend received	$ 2.3
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%

Commitments and Contingencies

9 Months Ended

Sep. 30, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

12. Commitments and Contingencies

Contract Obligations

As of September 30, 2023, the Company had outstanding total non-cancelable purchase obligations of $37.8 million, including $22.8 million for manufacture and supply of pamrevlumab, $2.2 million for manufacture and supply of roxadustat, and $12.8 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, 2023, 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 (for Gal-9 and CCR8), Medarex, Inc. and others. 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, 2023, the Company had $81.9 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, 2023, 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. Plaintiffs filed their consolidated amended complaint on October 29, 2021 and a corrected consolidated amended complaint on November 19, 2021 (the “Complaint”). The Complaint alleges false and misleading statements between December 2018 and June 2021 and seeks to represent a class of persons or entities that purchased FibroGen securities between December 20, 2018 and July 15, 2021. On July 15, 2022, the court issued an order denying Defendants’ motions to dismiss. Defendants answered the Complaint on September 13, 2022. On January 27, 2023, Plaintiffs filed a motion for class certification, which the court granted in part and denied in part on October 3, 2023. On October 17, 2023, the parties reached an agreement in principle to settle the class action at $28.5 million. Accordingly, as of September 30, 2023, the Company recorded the $28.5 million in accrued and other current liabilities in the condensed consolidated balance sheet. The Company maintains insurance that covers exposure related to the class action lawsuit. As the amount is fully recoverable under the Company’s insurance policies, the Company recorded a corresponding receivable in prepaid expenses and other current assets 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. 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, remains pending. Defendants filed a motion to dismiss the complaint in that case on September 20, 2023.

On July 30, 2021, a purported shareholder derivative complaint was filed in the U.S. District Court for the Northern District of California (the “California Federal Derivative”). On December 27, 2021, a second purported shareholder derivative complaint was filed in the U.S. District Court for the District of Delaware (the “Delaware Federal Derivative”). On April 14, 2022, a third purported shareholder derivative complaint was filed in the Delaware Court of Chancery (the “First Delaware Chancery Derivative”). On June 1, 2023, a fourth purported shareholder derivative complaint was filed in the Delaware Court of Chancery (the “Second Delaware Chancery Derivative”). All four derivative actions name FibroGen’s current and former officers and directors as defendants, as well as FibroGen as nominal defendant, and 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 California Federal Derivative action and the Delaware Federal Derivative action are stayed pending the resolution of any motions for summary judgment in the securities class action. The First and Second Delaware Chancery Derivative actions have been consolidated and the plaintiffs in the consolidated Delaware Chancery Derivative filed their amended complaint on November 3, 2023. On June 30, 2023, a fifth derivative action was filed in the U.S. District Court for the District of Delaware (the “Demand Refused Derivative”). The Demand Refused Derivative action names FibroGen’s current and former officers, as well as FibroGen as nominal defendant, and asserts state and federal claims based on some of the same alleged misstatements as the securities class action complaint. The Demand Refused Derivative has been stayed pending the outcome of any motion to dismiss the amended complaint in the Delaware Chancery Derivative.

The Company believes that the claims 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 Company is fully cooperating with the SEC. The Company cannot predict with any degree of certainty the outcome of the SEC’s investigation or determine the extent of any potential liabilities. The Company also cannot predict whether there will be any loss as a result of the investigation nor can it provide an estimate of the possible loss or range of loss. 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 August 3, 2022 and August 4, 2022, the Company’s Board of Directors received three 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. On March 27, 2023, the Company’s Board of Directors received another litigation demand from a purported shareholder of the Company, seeking similar action as the other litigation demands. 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.

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2023

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, 2023
	Level 1		Level 2		Level 3		Total
Money market funds	$	22,016	$	—	$	—	$	22,016
Corporate bonds		—		11,910		—		11,910
Commercial paper		—		78,800		—		78,800
U.S. government bonds		18,834		43,831		—		62,665
Agency bonds		—		4,967		—		4,967
Total	$	40,850	$	139,508	$	—	$	180,358

	December 31, 2022
	Level 1		Level 2		Level 3		Total
Money market funds	$	19,881	$	—	$	—	$	19,881
Corporate bonds		—		82,008		—		82,008
Commercial paper		—		57,381		—		57,381
U.S. government bonds		98,972		12,373		—		111,345
Agency bonds		—		11,468		—		11,468
Asset-backed securities		—		2,474		—		2,474
Foreign government bonds		—		4,980		—		4,980
Convertible promissory note		—		—		1,000		1,000
Total	$	118,853	$	170,684	$	1,000	$	290,537

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Preclinical and clinical trial accruals	$ 34,670	$ 57,780
API and bulk drug product price true-up	40,325	75,055
Litigation settlement	28,500	0
Payroll and related accruals	14,054	22,562
Accrued restructuring charge	4,694	0
Accrued co-promotion expenses - current	10,065	36,677
Roxadustat profit share to AstraZeneca	6,884	7,280
Property taxes and other taxes	7,950	7,691
Professional services	11,016	5,480
Current portion of liability related to sale of future revenues	5,860	0
Other	6,968	7,248
Total accrued and other current liabilities	$ 170,986	$ 219,773

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) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
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	$ 23,324	$ 31,538
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	(13)	(170)
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	18,387	159,627
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	(111)	(2,368)
Available for sale securities in continual unrealized loss position, estimated fair value	41,711	191,165
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	(124)	(2,538)
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	2,483	6,738
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	(8)	(147)
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	9,427	75,270
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	(69)	(925)
Available for sale securities in continual unrealized loss position, estimated fair value	11,910	82,008
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	(77)	(1,072)
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	17,360	22,326
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses	(4)	(13)
Available for sale securities in continual unrealized loss position, 12 months or more, estimated fair value	8,960	67,909
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses	(42)	(1,194)
Available for sale securities in continual unrealized loss position, estimated fair value	26,320	90,235
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	(46)	(1,207)
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		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		11,468
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses		(222)
Available for sale securities in continual unrealized loss position, estimated fair value		11,468
Available for sale securities in continual unrealized loss position, gross unrealized holding losses		(222)
Asset-backed securities [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		2,474
Available for sale securities in continual unrealized loss position, less than 12 months, gross unrealized holding losses		(10)
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		2,474
Available for sale securities in continual unrealized loss position, gross unrealized holding losses		(10)
Foreign 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		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		4,980
Available for sale securities in continual unrealized loss position, 12 months or more, gross unrealized holding losses		(27)
Available for sale securities in continual unrealized loss position, estimated fair value		4,980
Available for sale securities in continual unrealized loss position, gross unrealized holding losses		$ (27)
Commercial paper [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	3,481
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	3,481
Available for sale securities in continual unrealized loss position, gross unrealized holding losses	$ (1)

Liability Related to Sale of Future Revenues

9 Months Ended

Sep. 30, 2023

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 16.07% as of September 30, 2023.

The following table summarizes the activities of the liability related to sale of future revenues for the nine months ended September 30, 2023:


	Nine Months Ended September 30, 2023
Liability related to sale of future revenues - beginning balance	$	49,333
Interest expense recognized		5,636
Liability related to sale of future revenues - ending balance		54,969
Less: Current portion classified to accrued and other current liabilities		(5,860	)
Liability related to sale of future revenues, non-current	$	49,109

During the three and nine months ended September 30, 2023, the Company recognized, under Astellas Agreements, development revenue of $2.4 million and $5.8 million, respectively, and drug product revenue of $1.3 million and $17.7 million, respectively. See Note 2, Collaboration Agreements, License Agreement and Revenue, for details.

During the three and nine months ended September 30, 2023, the Company recognized the related non-cash interest expense of $2.1 million and $5.6 million, respectively.

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 to reach a Payment Cap up to $125.0 million by 2031.

Exclusive License and Option to Acquire Fortis Therapeutics (Tables)

9 Months Ended

Sep. 30, 2023

Business Combinations [Abstract]

Schedule of Allocation of Purchase Consideration Based on Estimated Fair Values of Acquired Assets

The following table represents the allocation of purchase consideration based on estimated fair values of the acquired assets (in thousands):


	Estimated Fair Value as of the Option Acquisition Date
Purchase consideration	$	—

Assets
Cash and cash equivalents		656
Prepaid expenses and other current assets		82
IPR&D assets		24,400
Total assets		25,138

Liabilities
Accounts payable		2,671
Accrued and other current liabilities		703
Total liabilities		3,374

Redeemable non-controlling interests		21,480
Nonredeemable non-controlling interests		520

Net identifiable assets, liabilities and non-controlling interests	$	(236	)

Loss on asset acquisition	$	(236	)

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	$ 7,325					$ 7,325		$ 12,739
Drug product revenue recognized	40,134			$ 15,735		120,614	$ 106,367
Other long-term liabilities	4,255					4,255		6,440
Astra Zeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty revenue recognized as drug product revenue						68,347
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,320			(4,077)		17,701	4,610
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,300					17,700
Drug Product Revenue, Net [Member] \| Europe [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	625			236		1,465	1,313
Drug Product Revenue, Net [Member] \| Europe [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized						28,700
Accrued liabilities								57,400
Drug Product Revenue, Net [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	600					1,500
Drug Product Revenue, Net [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized		$ 14,400	$ 1,700		$ 9,800
Drug Product Revenue, Net [Member] \| Japan [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	695			(4,313)		16,236	$ 3,297
Accrued liabilities	600					600		$ 6,500
Other long-term liabilities	700					700
Drug Product Revenue, Net [Member] \| API Shipment [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	700	$ 600		$ 4,300	$ 2,200
Bulk Drug Product [Member] \| Astra Zeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized						11,200
Bulk Drug Product [Member] \| Europe [Member] \| Astellas Europe Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accrued liabilities	$ 28,600					$ 28,600

Equity method investment - Variable Interest Entity (Tables)

9 Months Ended

Sep. 30, 2023

Acquisition And Variable Interest Entity [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, 2022		Share of Net Income		Dividend Received			Currency Translation			Balance at September 30, 2023
Falikang		51.1	%	$	5,061	$	2,023	$	(2,255	)	$	(295	)	$	4,534

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair value of U.S. treasury notes and bills transfered from level 1 to level 2	$ 8.5	$ 15.4

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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 18, 2023	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		$ 40,134	$ 15,735	$ 120,614	$ 106,367
Deferred Revenue		7,325		7,325			$ 12,739
Drug product revenue recognized		40,134	15,735	120,614	106,367
Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		29,390	17,359	77,439	59,495
Drug product revenue recognized		29,390	17,359	77,439	59,495
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		1,320	(4,077)	17,701	4,610
Drug product revenue recognized		1,320	(4,077)	17,701	4,610
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Recognized as Revenue				$ 68,347
AstraZeneca Agreements [Member] \| U.S./RoW [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent, non-refundable and time-based payments	$ 1,200,000
Additional consideration based on net sales description				low 20% range
Aggregate consideration received excluding drug product revenue		439,000		$ 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
Recognized as Revenue		3,500
Contract asset		4,000		4,000
Direct Sales [Member] \| Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		2,927	2,445	9,092	8,622
Drug product revenue recognized		$ 2,927	$ 2,445	$ 9,092	$ 8,622

Senior Secured Term Loan Facilities - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	Apr. 29, 2023	Sep. 30, 2023	Sep. 30, 2023	May 08, 2023
Debt Instrument [Line Items]
Amount received				$ 74.1
Issuance cost				0.9
Interest expense		$ 2.9	$ 4.5
Accrued interest		0.4	$ 0.4
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]
Term loan				75.0
Interest rate per annum		16.13%	16.13%
Issuance costs and related transaction costs, amortised				$ 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

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Cash	$ 70,982	$ 135,819
Commercial paper	22,942	0
Money market funds	22,016	19,881
U.S. government bonds	4,974	0
Total cash and cash equivalents	$ 120,914	$ 155,700

- Definition

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

+ References + Details

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Summary of Drug Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 40,134			$ 15,735		$ 120,614	$ 106,367
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,320			(4,077)		17,701	4,610
Drug Product Revenue, Net [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized		$ 14,400	$ 1,700		$ 9,800
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	1,300					17,700
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	695			(4,313)		16,236	3,297
Drug Product Revenue, Net [Member] \| Astellas Agreement [Member] \| Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 625			$ 236		$ 1,465	$ 1,313

- Definition

+ References

+ Details

Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2023

Accounting Policies [Abstract]

Description of Operations

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.

Restructuring Charge


	Three Months Ended September 30,				Nine Months Ended September 30,
	2023		2022		2023		2022
Employee stock options		11,293		9,715		10,022		9,794
RSUs, PRSUs and TSR awards		4,596		1,978		3,208		2,066
ESPP		559		50		556		390
		16,448		11,743		13,786		12,250

Risks and Uncertainties

Collaboration Agreements, License Agreement and Revenues

Astellas Agreements

Astellas Japan Agreement

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, 2023 and 2022 (in thousands):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2023			2022			2023			2022
Direct Sales:
Gross revenue	$	3,186		$	2,610		$	9,853		$	8,972
Discounts and rebates		(261	)		(166	)		(763	)		(353	)
Sales returns		2			1			2			3
Direct sales revenue, net		2,927			2,445			9,092			8,622

Sales to Falikang:
Gross transaction price		42,294			32,510			118,696			83,517
Profit share		(18,130	)		(12,980	)		(51,430	)		(31,894	)
Net transaction price		24,164			19,530			67,266			51,623
Decrease (increase) in deferred revenue		2,299			(4,616	)		1,081			(750	)
Sales to Falikang revenue, net		26,463			14,914			68,347			50,873
Total product revenue, net	$	29,390		$	17,359		$	77,439		$	59,495

Direct Sales

Sales to Falikang – China Performance Obligation

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, 2022			Additions			Recognized as Revenue		Currency Translation and Other		Balance at September 30, 2023
Product revenue - AstraZeneca China performance obligation - deferred revenue	$	(175,646	)	$	(72,519	)	$	68,347	$	2,242	$	(177,576	)

Drug Product Revenue

Drug Product Revenue, Net


	Three Months Ended September 30,					Nine Months Ended September 30,
	2023		2022			2023		2022
Astellas Japan Agreement	$	695	$	(4,313	)	$	16,236	$	3,297
Astellas Europe Agreement		625		236			1,465		1,313
Drug product revenue, net	$	1,320	$	(4,077	)	$	17,701	$	4,610

Astellas Japan Agreement

Astellas Europe Agreement

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, 2022			Additions		Recognized as Revenue		Reclassified to Accrued Liability / Accounts Payable		Balance at September 30, 2023
Drug product revenue - deferred revenue:
Astellas Europe Agreement	$	(40,303	)	$	—	$	1,465	$	28,685	$	(10,153	)

AstraZeneca U.S./RoW Agreement

There was no shipment of bulk drug product to AstraZeneca as commercial supply under the terms of the AstraZeneca Master Supply Agreement during the periods presented.

Collaboration Agreements, License Agreement and Revenues - Eluminex Agreement - Additional Information 2 (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended					9 Months Ended
	Jul. 31, 2021	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Apr. 30, 2023
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue		$ 40,134			$ 15,735		$ 120,614	$ 106,367
Eluminex [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Aggregate consideration received for milestone and upfront payments	$ 8,000
Future manufacturing clinical regulatory and commercial milestone payments	64,000
Commercial milestone	$ 36,000
Additional upfront payments									$ 1,500
Upfront payment		$ 500	$ 1,000
Eluminex [Member] \| Cornea Products [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Percentage of product manufacturing costs until manufacturing technology fully transferred						10.00%
China [Member] \| Eluminex [Member] \| Biosynthetic Cornea [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Milestone Payments				$ 3,000
Manufacturing related milestone payments				$ 3,000

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue:
Total revenue	$ 40,134	$ 15,735	$ 120,614	$ 106,367
Operating costs and expenses:
Cost of goods sold	$ 4,243	$ 4,308	$ 13,441	$ 15,355
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	$ 61,194	$ 75,182	$ 231,158	$ 235,163
Selling, general and administrative	25,573	29,902	91,029	90,722
Restructuring charge	12,606	0	12,606	0
Total operating costs and expenses	103,616	109,392	348,234	341,240
Loss from operations	(63,482)	(93,657)	(227,620)	(234,873)
Interest and other, net
Interest expense	(5,022)	(84)	(10,464)	(321)
Interest income and other income (expenses), net	4,296	1,798	7,984	6,672
Total interest and other, net	(726)	1,714	(2,480)	6,351
Loss before income taxes	(64,208)	(91,943)	(230,100)	(228,522)
Provision for (benefit from) income taxes	84	114	(77)	250
Investment income in unconsolidated variable interest entity	677	407	2,023	1,293
Net loss	$ (63,615)	$ (91,650)	$ (228,000)	$ (227,479)
Net loss per share - basic	$ (0.65)	$ (0.98)	$ (2.35)	$ (2.43)
Net loss per share - diluted	$ (0.65)	$ (0.98)	$ (2.35)	$ (2.43)
Weighted average number of common shares used to calculate net loss per share:
Basic	98,245	93,767	96,901	93,431
Diluted	98,245	93,767	96,901	93,431
License Revenue [Member]
Revenue:
Total revenue	$ 2,649	$ 0	$ 9,649	$ 22,590
Development and Other Revenue [Member]
Revenue:
Total revenue	6,775	2,453	15,825	19,672
Product Revenue, Net [Member]
Revenue:
Total revenue	29,390	17,359	77,439	59,495
Drug Product Revenue, Net [Member]
Revenue:
Total revenue	$ 1,320	$ (4,077)	$ 17,701	$ 4,610

Collaboration Agreements, License Agreement and Revenues - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation Of Revenue [Line Items]
Total revenue	$ 40,134	$ 15,735	$ 120,614	$ 106,367
Product Revenue, Net [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	29,390	17,359	77,439	59,495
Product Revenue, Net [Member] \| Direct Sales [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	3,186	2,610	9,853	8,972
Total revenue	2,927	2,445	9,092	8,622
Product Revenue, Net [Member] \| Direct Sales [Member] \| Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(261)	(166)	(763)	(353)
Product Revenue, Net [Member] \| Direct Sales [Member] \| Sales Returns [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2	1	2	3
Product Revenue, Net [Member] \| Sales To Falikang [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	26,463	14,914	68,347	50,873
Gross transfer price	42,294	32,510	118,696	83,517
Product Revenue, Net [Member] \| Sales To Falikang [Member] \| Profit Share [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(18,130)	(12,980)	(51,430)	(31,894)
Product Revenue, Net [Member] \| Sales To Falikang [Member] \| Net Transfer Price [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	24,164	19,530	67,266	51,623
Product Revenue, Net [Member] \| Sales To Falikang [Member] \| Decrease (Increase) in Deferred Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 2,299	$ (4,616)	$ 1,081	$ (750)

Equity method investment - Variable Interest Entity

9 Months Ended

Sep. 30, 2023

Acquisition And Variable Interest Entity [Abstract]

Equity method investment - Variable Interest Entity

4. Equity method investment - Variable Interest Entity

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. Falikang has not incurred material profit or loss to date. The Company may provide shareholder loans to Falikang to meet necessary financial obligations as part of its operations. To date, there has been no such loans. During the three months ended September 30, 2023, the Company received $2.3 million of dividend distribution from Falikang.

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


Entity	Ownership Percentage			Balance at December 31, 2022		Share of Net Income		Dividend Received			Currency Translation			Balance at September 30, 2023
Falikang		51.1	%	$	5,061	$	2,023	$	(2,255	)	$	(295	)	$	4,534

Falikang is considered a related party to the Company. See Note 11, Related Party Transactions, for related disclosures.

Collaboration Agreements, License Agreement and Revenues - Astellas Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended					6 Months Ended	9 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 40,134,000			$ 15,735,000			$ 120,614,000	$ 106,367,000
Deferred Revenue			7,325,000						7,325,000		$ 12,739,000
Drug Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			1,320,000			$ (4,077,000)			17,701,000	$ 4,610,000
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		$ 9,800,000
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] \| 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
Transaction price, variable consideration from estimated future co-development billing									$ 800,000
Percentage of joint development costs committed to fund	50.00%
Transaction price and allocated to performance obligations							$ 25,000,000
Changes in revenue from changes to estimated variable consideration			$ 0

At-the-Market Program - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Feb. 27, 2023	Sep. 30, 2023	Sep. 30, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Issuance of common stock under ATM Program		$ 48,407
Proceeds from sale of common stock		$ 3,686	$ 2,989
ATM Program [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Issuance of common stock under ATM Program	$ 200,000
Issuance of common stock under ATM Program shares		2,472,090
Proceeds from sale of common stock		$ 48,400
Weighted-average offering prices per share		$ 19.63

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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Reference 21: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

+ References + Details

Subsequent Event - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 14, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Subsequent Event [Line Items]
Restructuring plan, expected reduction to workforce, percentage	32.00%
Restructuring plan, non-recurring charges		$ 12,606	$ 0	$ 12,606	$ 0

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 130,426	$ 270,656
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	11,910	82,008
Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	55,858	57,381
Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		2,474
Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,980
Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		1,000
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	180,358	290,537
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	22,016	19,881
Fair Value, Measurements, Recurring [Member] \| Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	11,910	82,008
Fair Value, Measurements, Recurring [Member] \| Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	78,800	57,381
Fair Value, Measurements, Recurring [Member] \| U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	62,665	111,345
Fair Value, Measurements, Recurring [Member] \| Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	4,967	11,468
Fair Value, Measurements, Recurring [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		2,474
Fair Value, Measurements, Recurring [Member] \| Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,980
Fair Value, Measurements, Recurring [Member] \| Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		1,000
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	40,850	118,853
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	22,016	19,881
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	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	18,834	98,972
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	0
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Foreign government 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] \| Convertible promissory note [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	139,508	170,684
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	11,910	82,008
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	78,800	57,381
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	43,831	12,373
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	4,967	11,468
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		2,474
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,980
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
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	1,000
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	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	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	0
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Foreign 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] \| Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		$ 1,000