FibroGen (FGEN) 10-Q 9 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	Apr. 30, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
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		93,297,542

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 185,896	$ 171,223
Short-term investments	242,179	233,967
Accounts receivable, net ($38,755 and $10,930 from related parties)	43,883	17,401
Inventories	43,067	31,015
Prepaid expenses and other current assets	9,390	20,453
Total current assets	524,415	474,059
Restricted time deposits	2,072	2,072
Long-term investments	93,488	167,796
Property and equipment, net	26,881	28,277
Equity method investment in unconsolidated variable interest entity	4,155	3,825
Operating lease right-of-use assets	87,990	91,112
Other assets	6,933	6,680
Total assets	745,934	773,821
Current liabilities:
Accounts payable	36,353	26,097
Accrued and other current liabilities ($49,677 and $4 to a related party)	203,299	172,599
Deferred revenue ($3,303 and $3,201 to related parties)	4,744	15,857
Operating lease liabilities, current	10,978	10,944
Total current liabilities	255,374	225,497
Product development obligations	17,374	17,613
Deferred revenue, net of current ($26,285 and $25,891 to a related party)	184,893	186,801
Operating lease liabilities, non-current	85,948	88,776
Other long-term liabilities	24,330	26,021
Total liabilities	567,919	544,708
Commitments and Contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at March 31, 2022 and December 31, 2021
Common stock, $0.01 par value; 225,000 shares authorized at March 31, 2022 and December 31, 2021; 93,289 and 92,881 shares issued and outstanding at March 31, 2022 and December 31, 2021	933	929
Additional paid-in capital	1,490,859	1,476,414
Accumulated other comprehensive loss	(6,505)	(4,163)
Accumulated deficit	(1,327,239)	(1,264,034)
Total stockholders’ equity	158,048	209,146
Non-controlling interests	19,967	19,967
Total equity	178,015	229,113
Total liabilities, stockholders’ equity and non-controlling interests	$ 745,934	$ 773,821

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Accounts receivable from related parties	$ 38,755	$ 10,930
Accrued and other current liabilities to related party	49,677	4
Deferred revenue current to related party	3,303	3,201
Deferred revenue non-current to related party	$ 26,285	$ 25,891
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	125,000	125,000
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	225,000
Common stock, shares issued	93,289	92,881
Common stock, shares outstanding	93,289	92,881

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue:
Total revenue	$ 60,827	$ 38,429
Operating costs and expenses:
Cost of goods sold	$ 4,238	$ 3,401
Cost, Product and Service [Extensible List]	Product Revenue, Net [Member]	Product Revenue, Net [Member]
Research and development	$ 89,018	$ 74,676
Selling, general and administrative	30,564	30,779
Total operating costs and expenses	123,820	108,856
Loss from operations	(62,993)	(70,427)
Interest and other, net
Interest expense	(97)	(501)
Interest income and other income (expenses), net	(322)	(453)
Total interest and other, net	(419)	(954)
Loss before income taxes	(63,412)	(71,381)
Provision for income taxes	113	134
Investment income (loss) in unconsolidated variable interest entity	320	(240)
Net loss	$ (63,205)	$ (71,755)
Net loss per share - basic and diluted	$ (0.68)	$ (0.78)
Weighted average number of common shares used to calculate net loss per share - basic and diluted	93,043	91,688
License Revenue [Member]
Revenue:
Total revenue	$ 22,590	$ 0
Development and Other Revenue [Member]
Revenue:
Total revenue	11,762	14,587
Product Revenue, Net [Member]
Revenue:
Total revenue	18,881	15,362
Drug Product Revenue [Member]
Revenue:
Total revenue	$ 7,594	$ 8,480

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - Astellas Agreement [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
License and milestone revenue from a related party	$ 22,590	$ 0
Collaboration services and other revenue from a related party	5,180	3,611
Product revenue from a related party	16,223	10,406
Drug product revenue from a related party	$ 7,594	$ 4,030

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (63,205)	$ (71,755)
Other comprehensive income (loss):
Foreign currency translation adjustments	249	(70)
Available-for-sale investments:
Unrealized loss on investments, net of tax effect	(2,591)	(55)
Other comprehensive loss, net of taxes	(2,342)	(125)
Comprehensive loss	$ (65,547)	$ (71,880)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Equity (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]
Balance at Dec. 31, 2020	$ 441,449	$ 914	$ 1,399,774	$ (4,499)	$ (974,011)	$ 19,271
Balance, Shares at Dec. 31, 2020		91,440,633
Net income (loss)	(71,755)	$ 0	0	0	(71,755)	0
Change in unrealized gain or loss on investments	(55)	0	0	(55)	0	0
Foreign currency translation adjustments	(70)	0	0	(70)	0	0
Shares issued from stock plans, net of payroll taxes paid	1,320	$ 7	1,313	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		639,766
Stock-based compensation	19,384	$ 0	19,384	0		0
Balance at Mar. 31, 2021	390,273	$ 921	1,420,471	(4,624)	(1,045,766)	19,271
Balance, Shares at Mar. 31, 2021		92,080,399
Balance at Dec. 31, 2021	229,113	$ 929	1,476,414	(4,163)	(1,264,034)	19,967
Balance, Shares at Dec. 31, 2021		92,880,533
Net income (loss)	(63,205)	$ 0	0	0	(63,205)	0
Change in unrealized gain or loss on investments	(2,591)	0	0	(2,591)	0	0
Foreign currency translation adjustments	249	0	0	249	0	0
Shares issued from stock plans, net of payroll taxes paid	(2,703)	$ 4	(2,707)	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		408,051
Stock-based compensation	17,152	$ 0	17,152	0	0	0
Balance at Mar. 31, 2022	$ 178,015	$ 933	$ 1,490,859	$ (6,505)	$ (1,327,239)	$ 19,967
Balance, Shares at Mar. 31, 2022		93,288,584

Condensed Consolidated Statem_5

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net loss	$ (63,205)	$ (71,755)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,450	2,723
Amortization of finance lease right-of-use assets	134	2,616
Net accretion of premium and discount on investments	928	131
Investment (gain) loss in unconsolidated variable interest entity	(320)	240
Loss on disposal of property and equipment	5	0
Stock-based compensation	17,152	19,384
Realized loss on sales of available-for-sale securities	5	0
Changes in operating assets and liabilities:
Accounts receivable, net	(26,481)	1,336
Inventories	(12,000)	(4,288)
Prepaid expenses and other current assets	11,382	(5,457)
Operating lease right-of-use assets	3,132	(3,118)
Other assets	(459)	(2,503)
Accounts payable	10,207	(669)
Accrued and other liabilities	65,993	(294)
Operating lease liabilities, current	31	546
Deferred revenue	(13,024)	17,196
Accrued interest for finance lease liabilities	(21)	(29)
Operating lease liabilities, non-current	(2,835)	2,535
Other long-term liabilities	(1,550)	(3,578)
Net cash used in operating activities	(8,476)	(44,984)
Investing activities
Purchases of property and equipment	(1,638)	(518)
Payment made for acquired in-process research and development asset	(35,000)	0
Purchases of available-for-sale securities	20,912	196,243
Proceeds from sales of available-for-sale securities	7,382
Proceeds from maturities of investments	76,103	42
Net cash provided by (used in) investing activities	25,935	(196,719)
Financing activities
Repayments of finance lease liabilities	(1)	(3,299)
Repayments of lease obligations	(101)	(101)
Cash paid for payroll taxes on restricted stock unit releases	(2,974)	(4,757)
Proceeds from issuance of common stock	183	6,077
Net cash used in financing activities	(2,893)	(2,080)
Effect of exchange rate change on cash and cash equivalents	107	(1,102)
Net increase (decrease) in cash and cash equivalents	14,673	(244,885)
Total cash and cash equivalents at beginning of period	171,223	678,393
Total cash and cash equivalents at end of period	$ 185,896	$ 433,508

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
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 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, fibrotic disease, and cancer. Pamrevlumab, a human monoclonal antibody targeting connective tissue growth factor, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, locally advanced unresectable pancreatic cancer and Duchenne muscular dystrophy. Roxadustat is an oral small molecule inhibitor of HIF prolyl hydroxylase (“HIF-PH”) activity that is approved for the treatment of anemia caused by chronic kidney disease (“CKD”) in dialysis and non-dialysis patients, under the tradename EVRENZO ® , in the European Union, Great Britain, Japan, South Korea, Chile, Russia, the United Arab Emirates, and Kuwait. Roxadustat is being commercialized in China for CKD anemia in dialysis and non-dialysis patients under the tradename: 爱瑞卓 ® . Roxadustat is in Phase 3 clinical development for anemia associated with myelodysplastic syndromes. We have completed a Phase 2 study of roxadustat in chemotherapy-induced anemia and are running a Phase 3 trial for roxadustat in China. We have a pipeline of late-stage clinical programs as well as pre-clinical drug candidates at various stages of development that include both small molecules and biologics. We have leveraged our internally developed 2-oxoglutarate and connective tissue growth factor biology expertise as well as in-licensing of additional programs, such as antibodies targeting Galectin-9 protein (“Gal-9”) and C-C Motif Chemokine Receptor 8 (“CCR8”), to further enhance our late-stage preclinical pipeline. Our goal is to build a diversified pipeline with novel drugs that will address unmet patient needs in oncology, immunology, and fibrosis. 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, FibroGen Europe Oy and FibroGen China Anemia Holdings, Ltd. All inter-company transactions and balances have been eliminated in consolidation. For any variable interest entity (“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, 2021 , filed on February 28, 2022 and as amended on March 4, 2022 (“2021 Form 10-K”). 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, specifically, estimates in variable consideration for drug product sales, and estimates in transaction price per unit for the China performance obligation (as defined and discussed under Significant Accounting Policies below). 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 2021 Form 10-K, except for the updates to the following: Stock-Based Compensation The Company maintains equity incentive plans under which incentive and nonqualified stock options are granted to employees, which are comprised of stock options, service-based restricted stock units ("RSUs"), performance-based RSUs and total shareholder return (“TSR”) awards. The Company measures and recognizes compensation expense for all stock options, service and performance-based restricted stock units granted to its employees and directors based on the estimated fair value of the award on the grant date. The Company uses the Black-Scholes valuation model to estimate the fair value of stock option awards. The determination of the grant date fair value of options using the Black-Scholes valuation model is affected by the Company’s estimated common stock fair value and requires management to make a number of assumptions including the expected life of the option, the volatility of the underlying stock, the risk-free interest rate and expected dividends. To estimate the fair value of the TSR awards, the Company uses the Monte Carlo valuation model to simulate the probabilities of achievement, which requires management to make a number of assumptions including 30-day average price, volatility of the underlying stock and our peers, and the risk-free interest rate. The compensation cost of service-based stock options and restricted stock units is recognized net of any estimated forfeitures on a straight-line basis over the employee requisite service period. Compensation cost for performance-based RSUs is expensed over the respective vesting periods when the achievement of performance criteria is probable. Compensation cost for the TSR awards is recognized over the requisite service period, regardless of when, if ever, the market condition is satisfied. The Company believes that the fair value of stock options granted to non-employees is more reliably measured than the fair value of the services received. 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. For the three months ended March 31, 2022 and 2021, the Company reported a net loss, respectively. Therefore, dilutive common shares are not assumed to have been issued since their effect is anti-dilutive. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units (including service-based RSUs, performance-based RSUs and TSR awards) and shares to be purchased under the employee stock purchase plan totaling 12.2 millio n and 7.8 million for the three months ended March 31, 2022 and 2021 , respectively, as they were anti-dilutive. 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, rapid technological change, obtaining second source suppliers, regulatory approval from the U.S. Food and Drug Administration (“FDA”) or other regulatory authorities, the results of clinical trials and the achievement of milestones, market acceptance of the Company’s product candidates, competition from other products and larger companies, protection of proprietary technology, strategic relationships and dependence on key individuals. Recently Issued Accounting Guidance Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ ASU 2020-04” ) , which provides companies with optional financial reporting alternatives to reduce the cost and complexity associated with the accounting for contracts and hedging relationships affected by reference rate reform. This guidance is effective as of March 12, 2020 through December 31, 2022. Subsequently in January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope , which clarifies ASU 2020-04 and provides certain optional expedients that allow derivative instruments impacted by changes in the interest rate used for margining, discounting or contract price alignment to qualify for certain optional relief. ASU 2021-01 is effective in the same timeframe as ASU2020-04. The relief offered by this guidance, if adopted, is available to companies for the period March 12, 2020 through December 31, 2022. The Company has certain lease arrangements that are linked to t he London Inter-Bank Offered Rate (" LIBOR"). The Company is in the process of evaluating options for transitioning away from LIBOR and expects to complete this analysis by the time LIBOR is phased out. The Company did not elect to apply any of the expedients or exceptions as of and for the three months ended March 31, 2022 and is currently evaluating the impact on its condensed consolidated financial statements and related disclosures upon adoption of this guidance.

Collaboration Agreements, Licen

Collaboration Agreements, License Agreement and Revenues	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements, License Agreement and Revenues	2. Collaboration Agreements, License Agreement and Revenues Astellas Agreements 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 (“Japan Agreement”). Under this agreement, Astellas agreed to pay license fees, other upfront consideration and various milestone payments, totaling $ 172.6 million . The 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 March 31, 2022 totaled $ 105.1 million , excluding drug product revenue that is discussed separately below. Amounts recognized as license revenue and development revenue under the Japan Agreement with Astellas were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 Japan License revenue $ — $ — Development revenue $ 32 $ 80 The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Japan Agreement with Astellas, along with any associated deferred revenue as follows (in thousands): Japan Agreement Cumulative Deferred Total License $ 100,347 $ — $ 100,347 Development revenue 16,630 — 16,630 Total license and development $ 116,977 $ — $ 116,977 There was no 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 March 31, 2022 under the Japan Agreement. The Company does no t expect material variable consideration from estimated future co-development billing beyond the development period in the transaction price related to the Japan Agreement. In 2018, FibroGen and Astellas entered into an amendment to the Japan Agreement that allows Astellas to manufacture roxadustat drug product for commercialization in Japan (the “Japan Amendment”). The related drug product revenue, as described in details under Drug Product Revenue section below, was $ 7.6 million and $ 4.0 million for the three months ended March 31, 2022 and 2021, respectively. 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 (“Europe Agreement”). Under the terms of the Europe Agreement, Astellas agreed to pay license fees, other upfront consideration and various milestone payments, totaling $ 745.0 million . U nder the Europe Agreement, Astellas committed to fund 50 % of joint development costs for Europe and North America, and all territory-specific costs. The 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 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 Europe Agreement, all of which was recognized as revenue during the first quarter of 2022 from performance obligations satisfied. Such amount was billed and recorded in accounts receivable from Astellas as of March 31, 2022, and received in April 2022. The aggregate amount of consideration received under the Europe Agreement through March 31, 2022 totaled $ 660.0 million , excluding drug product revenue that is discussed separately below. Amounts recognized as license revenue and development revenue under the Europe Agreement with Astellas were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 Europe License revenue $ 22,590 $ — Development revenue $ 5,148 $ 3,531 The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Europe Agreement with Astellas, along with any associated deferred revenue as follows (in thousands): Europe Agreement Cumulative Deferred Total License $ 618,975 $ — $ 618,975 Development revenue 275,789 — 275,789 Total license and development $ 894,764 $ — $ 894,764 The revenue recognized under the Europe Agreement for the three months ended March 31, 2022 included an increase in revenue of $ 25.0 million resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods. The remainder of the transaction price related to the Europe Agreement includes $ 14.6 million of variable consideration from estimated future co-development billing and is expected to be recognized over the remaining development service period. Under the 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 under the Europe Agreement with 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. There was no related drug product revenue for the three months ended March 31, 2022 and 2021. See details under Drug Product Revenue section below. AstraZeneca Agreements U.S./Rest of World (“RoW”) Agreement Effective July 30, 2013, the Company entered into a collaboration agreement with 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 (“U.S./RoW Agreement”). It also excludes China, which is covered by a separate agreement with AstraZeneca described below. Under the terms of the 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 will pay the Comp any 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 will 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 U.S./RoW Agreement through March 31, 2022 totaled $ 439.0 million , excluding drug product revenue that is discussed separately below. While FibroGen and AstraZeneca continue to develop roxadustat in the U.S. for the treatment of anemia in patients with MDS, the Company has not been able to agree on a path forward for AstraZeneca to fund further roxadustat development for CKD anemia in the U.S. Therefore, the Company does not expect to receive most or all of the remaining U.S./RoW Agreement milestones from AstraZeneca. In 2020, the Company entered into Master Supply Agreement under the U.S./RoW Agreement with 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. There was no related drug product revenue for the three months ended March 31, 2022, and the related drug product revenue for the three months ended March 31, 2021 was $ 4.5 million . S ee details under Drug Product Revenue section below. China Agreement Effective July 30, 2013, the Company (through its subsidiaries affiliated with China) entered into the China Agreement (“China Agreement”). Under the terms of the China Agreement, AstraZeneca agreed to pay upfront consideration and potential milestone payments, totaling $ 376.7 million . The China Agreement is structured as a 50/50 profit or loss share (as defined), which was amended under the China Amendment discussed below in 2020, 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 March 31, 2022 totaled $ 77.2 million . 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 (collectively “FibroGen China”) and AstraZeneca entered into the China Amendment, relating to the development and commercialization of roxadustat in China. Under the China Amendment, in September 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 conduct sales and marketing through AstraZeneca. Since Falikang became fully operational in January 2021, 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 revenue under the U.S./RoW Agreement and China Agreement with AstraZeneca were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 U.S. / RoW License revenue $ — $ — Development revenue 5,819 10,976 The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the U.S./RoW Agreement and China Agreement with AstraZeneca, along with any associated deferred revenue as follows (in thousands): U.S. / RoW and China Agreements Cumulative Deferred Total License $ 341,844 $ — $ 341,844 Co-development, information sharing & 608,938 — 608,938 China performance obligation * 51,791 171,238 223,029 Total license and development $ 1,002,573 $ 171,238 ** $ 1,173,811 * China performance obligation revenue is recognized as product revenue, as described in details 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 March 31, 2022, deferred revenue included $ 160.0 million related to the U.S./RoW Agreement and China Agreement, which represents the net of $ 171.2 million of deferred revenue presented above and a $ 11.2 million unbilled co-development revenue under the China Amendment with AstraZeneca. There was no 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 March 31, 2022 under the U.S./RoW Agreement. The remainder of the transaction price related to the U.S./R oW Agreement and China Agreement includes $ 29.6 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. During the three months ended March 31, 2022 and 2021, the Company recognized $ 16.2 million and $ 10.4 million , respectively, of net product revenue from the sales to Falikang, as described in details under Product Revenue, Net section below. In addition to sales to Falikang, during the three months ended March 31, 2022 and 2021, the Company recognized $ 2.7 million and $ 5.0 million , respectively, of net product revenue from sales directly to d istributors in one province in China, as described as direct sales under Product Revenue, Net section below. 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 on January 21, 2022, Eluminex made an $ 8.0 million upfront payment to FibroGen during the first quarter of 2022, which was recorded as an unbilled contract asset as of December 31, 2021 in the prepaid expenses and other current assets in the condensed consolidated balance sheets. 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 n et sales of other recombinant human collagen type III products that are not cornea products. 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 110 % 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 months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 Eluminex Other revenue - contract manufacturing $ 762 $ — Product Revenue, Net Product revenue, net from the sales of roxadustat commercial product in China was as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, 2022 2021 Direct Sales: Gross revenue $ 2,830 $ 5,429 Discounts and rebates ( 175 ) ( 562 ) Sales returns 3 89 Direct sales revenue, net 2,658 4,956 Sales to Falikang: Gross transaction price 22,726 24,401 Profit share ( 8,849 ) ( 10,064 ) Net transaction price 13,877 14,337 Decrease (increase) in deferred revenue 2,346 ( 3,931 ) Sales to Falikang revenue, net 16,223 10,406 Total product revenue, net $ 18,881 $ 15,362 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 three months ended March 31, 2022 and 2021. 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 calculated at the individual distributor level. The following table includes a roll-forward of the contract liabilities (in thousands): Balance at Additions Deduction Currency Balance at Product revenue - Direct sales - contract liabilities $ ( 3,176 ) $ ( 407 ) $ 835 $ ( 11 ) $ ( 2,759 ) The above contract liabilities were included in accrued and other current liabilities in the condensed consolidated balance sheet. The rebates and discounts reflected as reductions to gross accounts receivable for direct sales wer e $ 0.6 million and $ 1.1 million a s of March 31, 2022 and December 31, 2021, respectively. Sales to Falikang – China Performance Obligation Since Falikang became fully operational in January 2021, 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 over future periods as the performance obligation is satisfied. Following updates to its estimates, the Company recognized $ 2.3 million from the previously deferred revenue of the China performance obligation during the three months ended March 31, 2022. The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands): Balance at Additions Recognized as Revenue Balance at Product revenue - AstraZeneca China $ ( 171,516 ) $ ( 15,945 ) $ 16,223 $ ( 171,238 ) 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 March 31, 2022 , approximately $ 12.6 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 $ 8.2 million and $13 .4 million as of March 31, 2022 and December 31, 2021 , respectively. Drug Product Revenue Drug product revenue from commercial-grade active pharmaceutical ingredient (“API”) or bulk drug product sales to AstraZeneca and Astellas was as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, 2022 2021 Astellas $ 7,594 $ 4,030 AstraZeneca — 4,450 Drug product revenue $ 7,594 $ 8,480 During the three months ended March 31, 2022 , the Company fulfilled a shipment obligation under the terms of Japan Amendment with Astellas, 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 Japan Amendment with Astellas, and recorded a reduction to the drug product revenue of $ 2.2 million du ring the three months ended March 31, 2022 , and $ 4.0 million additional drug product revenue during the three months ended March 31, 2021. 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 March 31, 2022 , the Company billed and received $ 49.2 million from Astellas related to the annual transfer price true up for bulk drug product transferred for commercial purposes under the terms of the Europe Agreement and the EU Supply Agreement with Astellas. This amount was recorded in deferred revenue and netted against an unbilled contract asset as of December 31, 2021. During the first quarter of 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 $ 45.5 million from deferred revenue to accrued liabilities as of March 31, 2022, representing its best estimate that this amount will be paid in the first quarter of 2023. During the three months ended March 31, 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 under the terms of the Master Supply Agreement. As a result, the Company reclassified $ 11.2 million from the related deferred revenue to accrued liabilities as of March 31, 2022. 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 Additions Reclassified to Accrued Liability Balance at Astellas - Japan Agreement $ ( 1,974 ) $ ( 2,226 ) $ 4,200 $ — Astellas - Europe Agreement ( 25,891 ) ( 49,160 ) 45,463 ( 29,588 ) AstraZeneca - U.S. Agreement ( 11,171 ) — 11,171 — Drug product revenue - deferred revenue $ ( 39,036 ) $ ( 51,386 ) $ 60,834 $ ( 29,588 )

Variable Interest Entity

Variable Interest Entity	3 Months Ended
	Mar. 31, 2022
Acquisition And Variable Interest Entity [Abstract]
Variable Interest Entity	3. 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, Consolidation (“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. Accordingly, 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, these loans have been immaterial. The Company’s equity method investment in Falikang was as follows (in thousands): Entity Ownership Percentage Balance at Share of Net Income Currency Balance at Falikang 51.1 % $ 3,825 $ 320 $ 10 $ 4,155 Falikang is considered a related party to the Company. See Note 7, Related Party Transactions , for related disclosures.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The fair values of the Company’s financial assets that are measured on a recurring basis are as follows (in thousands): March 31, 2022 Level 1 Level 2 Level 3 Total Money market funds $ 16,466 $ — $ — $ 16,466 Corporate bonds — 146,273 — 146,273 Commercial paper — 54,351 — 54,351 U.S. government bonds 98,376 — — 98,376 Agency bonds — 23,018 — 23,018 Asset-backed securities — 12,660 — 12,660 Foreign government bonds — 4,983 — 4,983 Total $ 114,842 $ 241,285 $ — $ 356,127 December 31, 2021 Level 1 Level 2 Level 3 Total Money market funds $ 58,801 $ — $ — $ 58,801 Corporate bonds — 182,646 — 182,646 Commercial paper — 69,079 — 69,079 U.S. government bonds 91,522 — — 91,522 Agency bonds — 23,275 — 23,275 Asset-backed securities — 27,087 — 27,087 Foreign government bonds — 9,154 — 9,154 Total $ 150,323 $ 311,241 $ — $ 461,564 The Company’s Level 2 investments are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar investments, issuer credit spreads, benchmark investments, prepayment/default projections based on historical data and other observable inputs. There were no transfers of assets between levels during the three months ended March 31, 2022 .

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	5. Balance Sheet Components Cash and Cash Equivalents Cash and cash equivalents consisted of the following (in thousands): March 31, 2022 December 31, 2021 Cash $ 165,436 $ 111,422 Commercial paper 3,994 1,000 Money market funds 16,466 58,801 Total cash and cash equivalents $ 185,896 $ 171,223 At March 31, 2022 and December 31, 2021 , a total of $ 95.2 million and $ 91.2 million, respectively, 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. Investments The Company’s investments consist of available-for-sale debt investments and marketable equity 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): March 31, 2022 Amortized Cost Gross Unrealized Gross Unrealized Fair Value Corporate bonds $ 148,022 $ — $ ( 1,749 ) $ 146,273 Commercial paper 50,357 — — 50,357 U.S. government bonds 99,764 — ( 1,388 ) 98,376 Agency bonds 23,279 — ( 261 ) 23,018 Asset-backed securities 12,693 — ( 33 ) 12,660 Foreign government bonds 5,044 — ( 61 ) 4,983 Total investments $ 339,159 $ — $ ( 3,492 ) $ 335,667 December 31, 2021 Amortized Cost Gross Unrealized Gross Unrealized Fair Value Corporate bonds $ 183,136 $ 2 $ ( 492 ) $ 182,646 Commercial paper 68,079 — — 68,079 U.S. government bonds 91,840 — ( 318 ) 91,522 Agency bonds 23,339 — ( 64 ) 23,275 Asset-backed securities 27,105 — ( 18 ) 27,087 Foreign government bonds 9,165 — ( 11 ) 9,154 Total investments $ 402,664 $ 2 $ ( 903 ) $ 401,763 At March 31, 2022 , the available-for-sale investments had contractual maturities range from several months to two years . During the three months ended March 31, 2022 , the Company did no t recognize any other-than-temporary impairment loss. Inventories Inventories consisted of the following (in thousands): March 31, 2022 December 31, 2021 Raw materials $ 1,359 $ 1,363 Work-in-progress 33,837 21,499 Finished goods 7,871 8,153 Total inventories $ 43,067 $ 31,015 As of March 31, 2022 and December 31, 2021 , inventory capitalized for the U.S. entity was 51 % and 38 % of the total inventory balance, respectively, which will be used for commercial launches in Europe and other territories where the Company has received regulatory approvals. The provision to write-down excess and obsolete inventory was immaterial as of March 31, 2022 and December 31, 2021. Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following (in thousands): March 31, 2022 December 31, 2021 Preclinical and clinical trial accruals $ 65,112 $ 56,283 API and bulk drug product price true-up 60,834 — Acquired in-process research and development asset — 35,000 Payroll and related accruals 12,325 20,909 Contract liabilities to pharmaceutical distributors 2,759 3,176 Accrued co-promotion expenses - current 28,117 25,746 Roxadustat profit share to AstraZeneca 7,917 7,895 Property taxes and other taxes 13,928 12,610 Professional services 6,819 6,074 Other 5,488 4,906 Total accrued and other current liabilities $ 203,299 $ 172,599 The accrued liabilities of $ 60.8 million for API and bulk drug product price true-up as of March 31, 2022 resulted from changes in estimated variable consideration associated with the API shipments fulfilled under the terms of the Japan Amendment with Astellas, the bulk drug product transferred under the terms of the Europe Agreement and the EU Supply Agreement with Astellas, and the bulk drug product shipments to AstraZeneca under the terms of the Master Supply Agreement. See Note 2, Collaboration Agreements, License Agreement and Revenues, for details. The acquired in-process research and development asset of $ 35.0 million as of December 31, 2021 was related to the upfront payment under the exclusive license and option agreement with HiFiBiO Therapeutics, which was paid during the three months ended March 31, 2022 .

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes Provisions for income tax for the three months ended March 31, 2022 and 2021 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.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	7. Related Party Transactions Astellas is an equity investor in the Company and is considered a related party. The Company recorded revenue related to collaboration agreements with Astellas of $ 27.8 million and $ 3.6 million for the three months ended March 31, 2022 and 2021, respectively. The Company also recorded drug product revenue from Astellas of $ 7.6 million and $ 4.0 million for the three months ended March 31, 2022 and 2021, 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 the three months ended March 31, 2022 and 2021. As of March 31, 2022 and December 31, 2021 , accounts receivable from Astellas were $ 37.6 million and $ 10.9 million, respectively. As of March 31, 2022 and December 31, 2021 , total deferred revenue from Astellas was $ 29.6 million and $ 27.9 million, respectively. As of March 31, 2022 , the amount due to Astellas was $ 49.7 million. As of December 31, 2021, amount due to Astellas was immaterial. 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 3, Variable Interest Entity , for details. For the three months ended March 31, 2022 and 2021, the net product revenue from Falikang was $ 16.2 million and $ 10.4 million , respectively. See Note 2, Collaboration Agreements, License Agreement and Revenues , for details. For the three months ended March 31, 2022 and 2021, the investment income (loss) in Falikang was $ 0.3 million and ($ 0.2 ) million , respectively. As of March 31, 2022 and December 31, 2021, the Company’s equity method investment in Falikang was $ 4.2 million and $ 3.8 million , respectively. See Note 3, Variable Interest Entity , for details. As of March 31, 2022 , accounts receivable, net, from Falikang was of $ 1.2 million. As of December 31, 2021 , accounts receivable, net, from Falikang was zero . The total deferred revenue from Falikang was zero as of March 31, 2022 . The total deferred revenue from Falikang was $ 1.2 million as of December 31, 2021 .

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Contract Obligations As of March 31, 2022, the Company had $ 96.9 million of operating lease liabilities. As of March 31, 2022 , the Company had outstanding total non-cancelable purchase obligations of $ 56.9 million, including $ 34.2 million for manufacture and supply of pamrevlumab, $ 12.2 million for manufacture and supply of roxadustat, and $ 10.5 million for other purchases. 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 March 31, 2022 , future milestone payments for research and pre-clinical stage development programs consisted of up to approximately $ 704.1 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. 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 in its condensed consolidated balance sheets as of March 31, 2022, as the Company could not predict the ultimate outcome of these matters, or reasonably estimate the potential exposure. In April 2021, three 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 FDA approval between November 2019 and December 2020. Plaintiffs seek to represent a class of persons or entities that purchased FibroGen securities between November 8, 2019 and April 6, 2021. In May 2021, two additional putative securities class action complaints were filed against Defendants alleging the same claims. One of the lawsuits alleges that Defendants made materially false and misleading statements between October 2017 and December 2020 and seeks to represent a class of persons or entities that purchased FibroGen securities between October 18, 2017 and April 6, 2021. The other lawsuit alleges that Defendants made materially false and misleading statements between December 2018 and February 2020 and seeks to represent a class of persons or entities that purchased FibroGen securities between December 20, 2018 and April 6, 2021. All plaintiffs seek unspecified monetary damages and other relief. 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. Defendants filed motions to dismiss the Complaint on January 14, 2021. Plaintiffs’ opposition to Defendants’ motions to dismiss is due March 4, 2022 and Defendants’ reply briefs are due April 8, 2022. A hearing on Defendants’ motions to dismiss was held on April 28, 2022. The Court has taken the motion under submission. On July 30, 2021, a purported shareholder derivative complaint was filed in the U.S. District Court for the Northern District of California. The complaint names as defendants ten of FibroGen’s current and former officers and directors, 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 complaint seeks unspecified damages, attorneys’ fees, and other costs. The parties have agreed to stay the action pending resolution of the motion to dismiss the securities class action. On December 27, 2021, a second purported shareholder derivative complaint was filed in the U.S. District Court for the District of Delaware. The complaint names seventeen of FibroGen’s current and former officers and directors as defendants, 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, as well as allegations of insider trading against certain defendants. The complaint seeks unspecified damages, attorneys’ fees, and other costs. The action has been stayed pending resolution of the motion to dismiss the securities class action. On April 14, 2022, a third purported shareholder derivative complaint was filed in the Delaware Chancery Court. It names the same defendants as the second purported shareholder derivative action and asserts similar claims based upon similar allegations. The complaint seeks unspecified damages, attorneys’ fees, and other costs. Defendants have not been served. 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. 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 has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, the Company believes the estimated fair value of these arrangements is minimal.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Description of Operations	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 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, fibrotic disease, and cancer. Pamrevlumab, a human monoclonal antibody targeting connective tissue growth factor, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, locally advanced unresectable pancreatic cancer and Duchenne muscular dystrophy. Roxadustat is an oral small molecule inhibitor of HIF prolyl hydroxylase (“HIF-PH”) activity that is approved for the treatment of anemia caused by chronic kidney disease (“CKD”) in dialysis and non-dialysis patients, under the tradename EVRENZO ® , in the European Union, Great Britain, Japan, South Korea, Chile, Russia, the United Arab Emirates, and Kuwait. Roxadustat is being commercialized in China for CKD anemia in dialysis and non-dialysis patients under the tradename: 爱瑞卓 ® . Roxadustat is in Phase 3 clinical development for anemia associated with myelodysplastic syndromes. We have completed a Phase 2 study of roxadustat in chemotherapy-induced anemia and are running a Phase 3 trial for roxadustat in China. We have a pipeline of late-stage clinical programs as well as pre-clinical drug candidates at various stages of development that include both small molecules and biologics. We have leveraged our internally developed 2-oxoglutarate and connective tissue growth factor biology expertise as well as in-licensing of additional programs, such as antibodies targeting Galectin-9 protein (“Gal-9”) and C-C Motif Chemokine Receptor 8 (“CCR8”), to further enhance our late-stage preclinical pipeline. Our goal is to build a diversified pipeline with novel drugs that will address unmet patient needs in oncology, immunology, and fibrosis.
Basis of Presentation and Principles of Consolidation	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, FibroGen Europe Oy and FibroGen China Anemia Holdings, Ltd. All inter-company transactions and balances have been eliminated in consolidation. For any variable interest entity (“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, 2021 , filed on February 28, 2022 and as amended on March 4, 2022 (“2021 Form 10-K”).
Use of Estimates	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, specifically, estimates in variable consideration for drug product sales, and estimates in transaction price per unit for the China performance obligation (as defined and discussed under Significant Accounting Policies below). 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	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 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, fibrotic disease, and cancer. Pamrevlumab, a human monoclonal antibody targeting connective tissue growth factor, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, locally advanced unresectable pancreatic cancer and Duchenne muscular dystrophy. Roxadustat is an oral small molecule inhibitor of HIF prolyl hydroxylase (“HIF-PH”) activity that is approved for the treatment of anemia caused by chronic kidney disease (“CKD”) in dialysis and non-dialysis patients, under the tradename EVRENZO ® , in the European Union, Great Britain, Japan, South Korea, Chile, Russia, the United Arab Emirates, and Kuwait. Roxadustat is being commercialized in China for CKD anemia in dialysis and non-dialysis patients under the tradename: 爱瑞卓 ® . Roxadustat is in Phase 3 clinical development for anemia associated with myelodysplastic syndromes. We have completed a Phase 2 study of roxadustat in chemotherapy-induced anemia and are running a Phase 3 trial for roxadustat in China. We have a pipeline of late-stage clinical programs as well as pre-clinical drug candidates at various stages of development that include both small molecules and biologics. We have leveraged our internally developed 2-oxoglutarate and connective tissue growth factor biology expertise as well as in-licensing of additional programs, such as antibodies targeting Galectin-9 protein (“Gal-9”) and C-C Motif Chemokine Receptor 8 (“CCR8”), to further enhance our late-stage preclinical pipeline. Our goal is to build a diversified pipeline with novel drugs that will address unmet patient needs in oncology, immunology, and fibrosis. 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, FibroGen Europe Oy and FibroGen China Anemia Holdings, Ltd. All inter-company transactions and balances have been eliminated in consolidation. For any variable interest entity (“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, 2021 , filed on February 28, 2022 and as amended on March 4, 2022 (“2021 Form 10-K”). 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, specifically, estimates in variable consideration for drug product sales, and estimates in transaction price per unit for the China performance obligation (as defined and discussed under Significant Accounting Policies below). 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 2021 Form 10-K, except for the updates to the following: Stock-Based Compensation The Company maintains equity incentive plans under which incentive and nonqualified stock options are granted to employees, which are comprised of stock options, service-based restricted stock units ("RSUs"), performance-based RSUs and total shareholder return (“TSR”) awards. The Company measures and recognizes compensation expense for all stock options, service and performance-based restricted stock units granted to its employees and directors based on the estimated fair value of the award on the grant date. The Company uses the Black-Scholes valuation model to estimate the fair value of stock option awards. The determination of the grant date fair value of options using the Black-Scholes valuation model is affected by the Company’s estimated common stock fair value and requires management to make a number of assumptions including the expected life of the option, the volatility of the underlying stock, the risk-free interest rate and expected dividends. To estimate the fair value of the TSR awards, the Company uses the Monte Carlo valuation model to simulate the probabilities of achievement, which requires management to make a number of assumptions including 30-day average price, volatility of the underlying stock and our peers, and the risk-free interest rate. The compensation cost of service-based stock options and restricted stock units is recognized net of any estimated forfeitures on a straight-line basis over the employee requisite service period. Compensation cost for performance-based RSUs is expensed over the respective vesting periods when the achievement of performance criteria is probable. Compensation cost for the TSR awards is recognized over the requisite service period, regardless of when, if ever, the market condition is satisfied. The Company believes that the fair value of stock options granted to non-employees is more reliably measured than the fair value of the services received. 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. For the three months ended March 31, 2022 and 2021, the Company reported a net loss, respectively. Therefore, dilutive common shares are not assumed to have been issued since their effect is anti-dilutive. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units (including service-based RSUs, performance-based RSUs and TSR awards) and shares to be purchased under the employee stock purchase plan totaling 12.2 millio n and 7.8 million for the three months ended March 31, 2022 and 2021 , respectively, as they were anti-dilutive. 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, rapid technological change, obtaining second source suppliers, regulatory approval from the U.S. Food and Drug Administration (“FDA”) or other regulatory authorities, the results of clinical trials and the achievement of milestones, market acceptance of the Company’s product candidates, competition from other products and larger companies, protection of proprietary technology, strategic relationships and dependence on key individuals. Recently Issued Accounting Guidance Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ ASU 2020-04” ) , which provides companies with optional financial reporting alternatives to reduce the cost and complexity associated with the accounting for contracts and hedging relationships affected by reference rate reform. This guidance is effective as of March 12, 2020 through December 31, 2022. Subsequently in January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope , which clarifies ASU 2020-04 and provides certain optional expedients that allow derivative instruments impacted by changes in the interest rate used for margining, discounting or contract price alignment to qualify for certain optional relief. ASU 2021-01 is effective in the same timeframe as ASU2020-04. The relief offered by this guidance, if adopted, is available to companies for the period March 12, 2020 through December 31, 2022. The Company has certain lease arrangements that are linked to t he London Inter-Bank Offered Rate (" LIBOR"). The Company is in the process of evaluating options for transitioning away from LIBOR and expects to complete this analysis by the time LIBOR is phased out. The Company did not elect to apply any of the expedients or exceptions as of and for the three months ended March 31, 2022 and is currently evaluating the impact on its condensed consolidated financial statements and related disclosures upon adoption of this guidance.
Stock-Based Compensation	Stock-Based Compensation The Company maintains equity incentive plans under which incentive and nonqualified stock options are granted to employees, which are comprised of stock options, service-based restricted stock units ("RSUs"), performance-based RSUs and total shareholder return (“TSR”) awards. The Company measures and recognizes compensation expense for all stock options, service and performance-based restricted stock units granted to its employees and directors based on the estimated fair value of the award on the grant date. The Company uses the Black-Scholes valuation model to estimate the fair value of stock option awards. The determination of the grant date fair value of options using the Black-Scholes valuation model is affected by the Company’s estimated common stock fair value and requires management to make a number of assumptions including the expected life of the option, the volatility of the underlying stock, the risk-free interest rate and expected dividends. To estimate the fair value of the TSR awards, the Company uses the Monte Carlo valuation model to simulate the probabilities of achievement, which requires management to make a number of assumptions including 30-day average price, volatility of the underlying stock and our peers, and the risk-free interest rate. The compensation cost of service-based stock options and restricted stock units is recognized net of any estimated forfeitures on a straight-line basis over the employee requisite service period. Compensation cost for performance-based RSUs is expensed over the respective vesting periods when the achievement of performance criteria is probable. Compensation cost for the TSR awards is recognized over the requisite service period, regardless of when, if ever, the market condition is satisfied. The Company believes that the fair value of stock options granted to non-employees is more reliably measured than the fair value of the services received.
Net Loss per Share	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. For the three months ended March 31, 2022 and 2021, the Company reported a net loss, respectively. Therefore, dilutive common shares are not assumed to have been issued since their effect is anti-dilutive. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units (including service-based RSUs, performance-based RSUs and TSR awards) and shares to be purchased under the employee stock purchase plan totaling 12.2 millio n and 7.8 million for the three months ended March 31, 2022 and 2021 , respectively, as they were anti-dilutive.
Risks and Uncertainties	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, rapid technological change, obtaining second source suppliers, regulatory approval from the U.S. Food and Drug Administration (“FDA”) or other regulatory authorities, the results of clinical trials and the achievement of milestones, market acceptance of the Company’s product candidates, competition from other products and larger companies, protection of proprietary technology, strategic relationships and dependence on key individuals.
Recently Issued Accounting Guidance Not Yet Adopted	Recently Issued Accounting Guidance Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ ASU 2020-04” ) , which provides companies with optional financial reporting alternatives to reduce the cost and complexity associated with the accounting for contracts and hedging relationships affected by reference rate reform. This guidance is effective as of March 12, 2020 through December 31, 2022. Subsequently in January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope , which clarifies ASU 2020-04 and provides certain optional expedients that allow derivative instruments impacted by changes in the interest rate used for margining, discounting or contract price alignment to qualify for certain optional relief. ASU 2021-01 is effective in the same timeframe as ASU2020-04. The relief offered by this guidance, if adopted, is available to companies for the period March 12, 2020 through December 31, 2022. The Company has certain lease arrangements that are linked to t he London Inter-Bank Offered Rate (" LIBOR"). The Company is in the process of evaluating options for transitioning away from LIBOR and expects to complete this analysis by the time LIBOR is phased out. The Company did not elect to apply any of the expedients or exceptions as of and for the three months ended March 31, 2022 and is currently evaluating the impact on its condensed consolidated financial statements and related disclosures upon adoption of this guidance.
Collaboration Agreements, License Agreement and Revenues	Astellas Agreements 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 (“Japan Agreement”). Under this agreement, Astellas agreed to pay license fees, other upfront consideration and various milestone payments, totaling $ 172.6 million . The 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 March 31, 2022 totaled $ 105.1 million , excluding drug product revenue that is discussed separately below.
Product Revenue, Net	Product Revenue, Net Product revenue, net from the sales of roxadustat commercial product in China was as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, 2022 2021 Direct Sales: Gross revenue $ 2,830 $ 5,429 Discounts and rebates ( 175 ) ( 562 ) Sales returns 3 89 Direct sales revenue, net 2,658 4,956 Sales to Falikang: Gross transaction price 22,726 24,401 Profit share ( 8,849 ) ( 10,064 ) Net transaction price 13,877 14,337 Decrease (increase) in deferred revenue 2,346 ( 3,931 ) Sales to Falikang revenue, net 16,223 10,406 Total product revenue, net $ 18,881 $ 15,362 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 three months ended March 31, 2022 and 2021. 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 calculated at the individual distributor level. The following table includes a roll-forward of the contract liabilities (in thousands): Balance at Additions Deduction Currency Balance at Product revenue - Direct sales - contract liabilities $ ( 3,176 ) $ ( 407 ) $ 835 $ ( 11 ) $ ( 2,759 ) The above contract liabilities were included in accrued and other current liabilities in the condensed consolidated balance sheet. The rebates and discounts reflected as reductions to gross accounts receivable for direct sales wer e $ 0.6 million and $ 1.1 million a s of March 31, 2022 and December 31, 2021, respectively. Sales to Falikang – China Performance Obligation Since Falikang became fully operational in January 2021, 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 over future periods as the performance obligation is satisfied. Following updates to its estimates, the Company recognized $ 2.3 million from the previously deferred revenue of the China performance obligation during the three months ended March 31, 2022. The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands): Balance at Additions Recognized as Revenue Balance at Product revenue - AstraZeneca China $ ( 171,516 ) $ ( 15,945 ) $ 16,223 $ ( 171,238 ) 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 March 31, 2022 , approximately $ 12.6 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 $ 8.2 million and $13 .4 million as of March 31, 2022 and December 31, 2021 , respectively.
Drug Product Revenue	Drug Product Revenue Drug product revenue from commercial-grade active pharmaceutical ingredient (“API”) or bulk drug product sales to AstraZeneca and Astellas was as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, 2022 2021 Astellas $ 7,594 $ 4,030 AstraZeneca — 4,450 Drug product revenue $ 7,594 $ 8,480 During the three months ended March 31, 2022 , the Company fulfilled a shipment obligation under the terms of Japan Amendment with Astellas, 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 Japan Amendment with Astellas, and recorded a reduction to the drug product revenue of $ 2.2 million du ring the three months ended March 31, 2022 , and $ 4.0 million additional drug product revenue during the three months ended March 31, 2021. 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 March 31, 2022 , the Company billed and received $ 49.2 million from Astellas related to the annual transfer price true up for bulk drug product transferred for commercial purposes under the terms of the Europe Agreement and the EU Supply Agreement with Astellas. This amount was recorded in deferred revenue and netted against an unbilled contract asset as of December 31, 2021. During the first quarter of 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 $ 45.5 million from deferred revenue to accrued liabilities as of March 31, 2022, representing its best estimate that this amount will be paid in the first quarter of 2023. During the three months ended March 31, 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 under the terms of the Master Supply Agreement. As a result, the Company reclassified $ 11.2 million from the related deferred revenue to accrued liabilities as of March 31, 2022. 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 Additions Reclassified to Accrued Liability Balance at Astellas - Japan Agreement $ ( 1,974 ) $ ( 2,226 ) $ 4,200 $ — Astellas - Europe Agreement ( 25,891 ) ( 49,160 ) 45,463 ( 29,588 ) AstraZeneca - U.S. Agreement ( 11,171 ) — 11,171 — Drug product revenue - deferred revenue $ ( 39,036 ) $ ( 51,386 ) $ 60,834 $ ( 29,588 )

Collaboration Agreements, Lic_2

Collaboration Agreements, License Agreement and Revenues (Tables)	3 Months Ended
	Mar. 31, 2022
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue and Product Revenue Net	Product revenue, net from the sales of roxadustat commercial product in China was as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, 2022 2021 Direct Sales: Gross revenue $ 2,830 $ 5,429 Discounts and rebates ( 175 ) ( 562 ) Sales returns 3 89 Direct sales revenue, net 2,658 4,956 Sales to Falikang: Gross transaction price 22,726 24,401 Profit share ( 8,849 ) ( 10,064 ) Net transaction price 13,877 14,337 Decrease (increase) in deferred revenue 2,346 ( 3,931 ) Sales to Falikang revenue, net 16,223 10,406 Total product revenue, net $ 18,881 $ 15,362
Summary of Amounts Recognized as Revenue	Amounts recognized as revenue under the Eluminex were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 Eluminex Other revenue - contract manufacturing $ 762 $ —
Roll-forward of Related Contract Liabilities	The following table includes a roll-forward of the contract liabilities (in thousands): Balance at Additions Deduction Currency Balance at Product revenue - Direct sales - contract liabilities $ ( 3,176 ) $ ( 407 ) $ 835 $ ( 11 ) $ ( 2,759 )
Schedule of Drug Product Revenue	Drug product revenue from commercial-grade active pharmaceutical ingredient (“API”) or bulk drug product sales to AstraZeneca and Astellas was as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, 2022 2021 Astellas $ 7,594 $ 4,030 AstraZeneca — 4,450 Drug product revenue $ 7,594 $ 8,480
Drug Product Revenue [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 Additions Reclassified to Accrued Liability Balance at Astellas - Japan Agreement $ ( 1,974 ) $ ( 2,226 ) $ 4,200 $ — Astellas - Europe Agreement ( 25,891 ) ( 49,160 ) 45,463 ( 29,588 ) AstraZeneca - U.S. Agreement ( 11,171 ) — 11,171 — Drug product revenue - deferred revenue $ ( 39,036 ) $ ( 51,386 ) $ 60,834 $ ( 29,588 )
AstraZeneca Agreements [Member]
Roll-forward of Related Contract Liabilities	The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands): Balance at Additions Recognized as Revenue Balance at Product revenue - AstraZeneca China $ ( 171,516 ) $ ( 15,945 ) $ 16,223 $ ( 171,238 ) 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
Japan [Member]
Summary of License Revenue and Development Revenue Recognized under Agreement	Amounts recognized as license revenue and development revenue under the Japan Agreement with Astellas were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 Japan License revenue $ — $ — Development revenue $ 32 $ 80
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue and Product Revenue Net	The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Japan Agreement with Astellas, along with any associated deferred revenue as follows (in thousands): Japan Agreement Cumulative Deferred Total License $ 100,347 $ — $ 100,347 Development revenue 16,630 — 16,630 Total license and development $ 116,977 $ — $ 116,977
Europe [Member]
Summary of License Revenue and Development Revenue Recognized under Agreement	Amounts recognized as license revenue and development revenue under the Europe Agreement with Astellas were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 Europe License revenue $ 22,590 $ — Development revenue $ 5,148 $ 3,531
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue and Product Revenue Net	The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Europe Agreement with Astellas, along with any associated deferred revenue as follows (in thousands): Europe Agreement Cumulative Deferred Total License $ 618,975 $ — $ 618,975 Development revenue 275,789 — 275,789 Total license and development $ 894,764 $ — $ 894,764
U.S./RoW and China [Member]
Summary of License Revenue and Development Revenue Recognized under Agreement	Amounts recognized as revenue under the U.S./RoW Agreement and China Agreement with AstraZeneca were as follows for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2022 2021 U.S. / RoW License revenue $ — $ — Development revenue 5,819 10,976
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue and Product Revenue Net	The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the U.S./RoW Agreement and China Agreement with AstraZeneca, along with any associated deferred revenue as follows (in thousands): U.S. / RoW and China Agreements Cumulative Deferred Total License $ 341,844 $ — $ 341,844 Co-development, information sharing & 608,938 — 608,938 China performance obligation * 51,791 171,238 223,029 Total license and development $ 1,002,573 $ 171,238 ** $ 1,173,811 * China performance obligation revenue is recognized as product revenue, as described in details 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 March 31, 2022, deferred revenue included $ 160.0 million related to the U.S./RoW Agreement and China Agreement, which represents the net of $ 171.2 million of deferred revenue presented above and a $ 11.2 million unbilled co-development revenue under the China Amendment with AstraZeneca.

Variable Interest Entity (Table

Variable Interest Entity (Tables)	3 Months Ended
	Mar. 31, 2022
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 Share of Net Income Currency Balance at Falikang 51.1 % $ 3,825 $ 320 $ 10 $ 4,155

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
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): March 31, 2022 Level 1 Level 2 Level 3 Total Money market funds $ 16,466 $ — $ — $ 16,466 Corporate bonds — 146,273 — 146,273 Commercial paper — 54,351 — 54,351 U.S. government bonds 98,376 — — 98,376 Agency bonds — 23,018 — 23,018 Asset-backed securities — 12,660 — 12,660 Foreign government bonds — 4,983 — 4,983 Total $ 114,842 $ 241,285 $ — $ 356,127 December 31, 2021 Level 1 Level 2 Level 3 Total Money market funds $ 58,801 $ — $ — $ 58,801 Corporate bonds — 182,646 — 182,646 Commercial paper — 69,079 — 69,079 U.S. government bonds 91,522 — — 91,522 Agency bonds — 23,275 — 23,275 Asset-backed securities — 27,087 — 27,087 Foreign government bonds — 9,154 — 9,154 Total $ 150,323 $ 311,241 $ — $ 461,564

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): March 31, 2022 December 31, 2021 Cash $ 165,436 $ 111,422 Commercial paper 3,994 1,000 Money market funds 16,466 58,801 Total cash and cash equivalents $ 185,896 $ 171,223
Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Investments	The Company’s investments consist of available-for-sale debt investments and marketable equity 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): March 31, 2022 Amortized Cost Gross Unrealized Gross Unrealized Fair Value Corporate bonds $ 148,022 $ — $ ( 1,749 ) $ 146,273 Commercial paper 50,357 — — 50,357 U.S. government bonds 99,764 — ( 1,388 ) 98,376 Agency bonds 23,279 — ( 261 ) 23,018 Asset-backed securities 12,693 — ( 33 ) 12,660 Foreign government bonds 5,044 — ( 61 ) 4,983 Total investments $ 339,159 $ — $ ( 3,492 ) $ 335,667 December 31, 2021 Amortized Cost Gross Unrealized Gross Unrealized Fair Value Corporate bonds $ 183,136 $ 2 $ ( 492 ) $ 182,646 Commercial paper 68,079 — — 68,079 U.S. government bonds 91,840 — ( 318 ) 91,522 Agency bonds 23,339 — ( 64 ) 23,275 Asset-backed securities 27,105 — ( 18 ) 27,087 Foreign government bonds 9,165 — ( 11 ) 9,154 Total investments $ 402,664 $ 2 $ ( 903 ) $ 401,763
Schedule of Inventory	Inventories consisted of the following (in thousands): March 31, 2022 December 31, 2021 Raw materials $ 1,359 $ 1,363 Work-in-progress 33,837 21,499 Finished goods 7,871 8,153 Total inventories $ 43,067 $ 31,015
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): March 31, 2022 December 31, 2021 Preclinical and clinical trial accruals $ 65,112 $ 56,283 API and bulk drug product price true-up 60,834 — Acquired in-process research and development asset — 35,000 Payroll and related accruals 12,325 20,909 Contract liabilities to pharmaceutical distributors 2,759 3,176 Accrued co-promotion expenses - current 28,117 25,746 Roxadustat profit share to AstraZeneca 7,917 7,895 Property taxes and other taxes 13,928 12,610 Professional services 6,819 6,074 Other 5,488 4,906 Total accrued and other current liabilities $ 203,299 $ 172,599

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail) shares in Millions	3 Months Ended
	Mar. 31, 2022Segmentshares	Mar. 31, 2021shares
Accounting Policy [Line Items]
Number of reportable segment | Segment	1
Anti-dilutive shares outstanding | shares	12.2	7.8

Collaboration Agreements, Lic_3

Collaboration Agreements, License Agreement and Revenues - Astellas Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 60,827,000	$ 38,429,000
Deferred Revenue			4,744,000		$ 15,857,000
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			7,594,000	8,480,000
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 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			9,800,000
Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price, variable consideration from estimated future co-development billing			$ 14,600,000
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
Revenue resulting from changes to estimated variable consideration			0
Astellas Agreement [Member] | Japan [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 7,600,000	4,000,000
Astellas Agreement [Member] | Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received	$ 745,000,000
Additional consideration based on net sales description			low 20% range
Aggregate consideration received excluding drug product revenue			$ 660,000,000
Total revenue			0	$ 0
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			$ 25,000,000

Collaboration Agreements, Lic_4

Collaboration Agreements, License Agreement and Revenues - AstraZeneca Agreements - Additional Information 1 (Detail) - USD ($)	Jul. 30, 2013	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		$ 60,827,000	$ 38,429,000
Deferred Revenue		4,744,000		$ 15,857,000
Drug product revenue recognized		60,827,000	38,429,000
Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		18,881,000	15,362,000
Drug product revenue recognized		18,881,000	15,362,000
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		7,594,000	8,480,000
Drug product revenue recognized		7,594,000	8,480,000
AstraZeneca Agreements [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		0	4,450,000
Drug product revenue recognized		$ 0	4,450,000
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	$ 1,200,000,000
Additional consideration based on net sales description		low 20% range
Aggregate consideration received excluding drug product revenue		$ 439,000,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		0	4,500,000
Drug product revenue recognized		0	4,500,000
AstraZeneca Agreements [Member] | China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent, non-refundable and time-based payments	$ 376,700,000
Aggregate considerations received		77,200,000
AstraZeneca Agreements [Member] | China [Member] | Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		16,200,000	10,400,000
Drug product revenue recognized		16,200,000	10,400,000
Direct Sales [Member] | Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		2,658,000	4,956,000
Drug product revenue recognized		2,658,000	4,956,000
Direct Sales [Member] | China [Member] | Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue		2,700,000	5,000,000
Drug product revenue recognized		$ 2,700,000	$ 5,000,000

Collaboration Agreements, Lic_5

Collaboration Agreements, License Agreement and Revenues - Eluminex Agreement - Additional Information 2 (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jul. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue		$ 60,827	$ 38,429
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
Eluminex [Member] | Cornea Products [Member] | ASC 606 [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Percentage of product manufacturing costs until manufacturing technology fully transferred		110.00%

Collaboration Agreements, Lic_6

Collaboration Agreements, License Agreement and Revenues - Summary of License Revenue and Development Revenue Recognized under Agreement (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 60,827,000	$ 38,429,000
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	22,590,000	0
Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	11,762,000	14,587,000
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
Astellas Agreement [Member] | License Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
Astellas Agreement [Member] | License Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	22,590,000	0
Astellas Agreement [Member] | Development Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	32,000	80,000
Astellas Agreement [Member] | Development Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	5,148,000	3,531,000
AstraZeneca Agreements [Member] | License Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
AstraZeneca Agreements [Member] | Development Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 5,819,000	$ 10,976,000

Collaboration Agreements, Lic_7

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	Mar. 31, 2022	Dec. 31, 2021
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	$ 116,977
Deferred Revenue	0
Total Consideration	116,977
Astellas Agreement [Member] | Japan [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	16,630
Deferred Revenue	0
Total Consideration	16,630
Astellas Agreement [Member] | Japan [Member] | License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	100,347
Deferred Revenue	0
Total Consideration	100,347
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	894,764
Deferred Revenue	0
Total Consideration	894,764
Astellas Agreement [Member] | Europe [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	275,789
Deferred Revenue	0
Total Consideration	275,789
Astellas Agreement [Member] | Europe [Member] | License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	618,975
Deferred Revenue	0
Total Consideration	618,975
AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	171,238	$ 171,516
AstraZeneca Agreements [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	1,002,573
Deferred Revenue	171,238
Total Consideration	1,173,811
AstraZeneca Agreements [Member] | U.S./RoW and China [Member] | License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	341,844
Deferred Revenue	0
Total Consideration	341,844
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	608,938
Deferred Revenue	0
Total Consideration	608,938
AstraZeneca Agreements [Member] | U.S./RoW and China [Member] | China performance obligation [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	51,791
Deferred Revenue	171,238
Total Consideration	$ 223,029

Collaboration Agreements, Lic_8

Collaboration Agreements, License Agreement and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail)	3 Months Ended
	Mar. 31, 2022USD ($)
Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Remainder of transaction price, variable consideration from estimated future co-development billing	$ 14,600,000
Europe [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue from changes to estimated variable consideration	25,000,000
U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Remainder of transaction price, variable consideration from estimated future co-development billing	29,600,000
Changes in revenue from changes to estimated variable consideration	$ 0

Collaboration Agreements, Lic_9

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	Mar. 31, 2022	Dec. 31, 2021
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue, net of current ($26,285 and $25,891 to a related party)	$ 184,893	$ 186,801
AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	171,238	$ 171,516
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue, net of current ($26,285 and $25,891 to a related party)	160,000
Deferred Revenue	171,200
Net unbilled co-development revenue	$ 11,200

Collaboration Agreements, Li_10

Collaboration Agreements, License Agreement and Revenues - Summary of Amounts Recognized as Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 60,827	$ 38,429
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	22,590	0
License Revenue [Member] | Eluminex [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 762	$ 0

Collaboration Agreements, Li_11

Collaboration Agreements, License Agreement and Revenues - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Total revenue	$ 60,827	$ 38,429
Product Revenue, Net [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	18,881	15,362
Product Revenue, Net [Member] | Direct Sales [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	2,830	5,429
Total revenue	2,658	4,956
Product Revenue, Net [Member] | Direct Sales [Member] | Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(175)	(562)
Product Revenue, Net [Member] | Direct Sales [Member] | Sales Returns [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	3	89
Product Revenue, Net [Member] | Sales To Falikang [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	16,223	10,406
Gross transfer price	22,726	24,401
Product Revenue, Net [Member] | Sales To Falikang [Member] | Profit Share [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(8,849)	(10,064)
Product Revenue, Net [Member] | Sales To Falikang [Member] | Net Transfer Price [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	13,877	14,337
Product Revenue, Net [Member] | Sales To Falikang [Member] | Increase in Deferred Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ (2,346)	$ (3,931)

Collaboration Agreements, Li_12

Collaboration Agreements, License Agreement and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 60,827	$ 38,429
Rebates and Discounts [Member] | Gross Accounts Receivable [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	600		$ 1,100
Constrained for Future Recognition [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 2,300

Collaboration Agreements, Li_13

Collaboration Agreements, License Agreement and Revenues - Roll-forward of Related Contract Liabilities (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)
AstraZeneca Agreements [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2021	$ (171,516)
Additions	(15,945)
Recognized as Revenue	16,223
Balance at March 31, 2022	(171,238)
Product Revenue, Net [Member] | Direct Sales [Member] | Contract Liabilities [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2021	(3,176)
Additions	(407)
Deduction	835
Currency Translation and Other	(11)
Balance at March 31, 2022	(2,759)
Drug Product Revenue [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2021	(39,036)
Additions	(51,386)
Reclassified to Accrued Liability	60,834
Balance at March 31, 2022	(29,588)
Drug Product Revenue [Member] | AstraZeneca Agreements [Member] | U.S. [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2021	(11,171)
Reclassified to Accrued Liability	11,171
Drug Product Revenue [Member] | Astellas Agreement [Member] | Japan [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2021	(1,974)
Additions	(2,226)
Reclassified to Accrued Liability	4,200
Drug Product Revenue [Member] | Astellas Agreement [Member] | Europe [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2021	(25,891)
Additions	(49,160)
Reclassified to Accrued Liability	45,463
Balance at March 31, 2022	$ (29,588)

Collaboration Agreements, Li_14

Collaboration Agreements, License Agreement and Revenues - Deferred Revenue - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Product Revenue, Net [Member] | Beijing Falikang Pharmaceutical Co Ltd
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reductions to gross accounts receivable	$ 8,200	$ 400
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue	171,238	$ 171,516
AstraZeneca Agreements [Member] | China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue	$ 12,600

Collaboration Agreements, Li_15

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Summary of Drug Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 60,827	$ 38,429
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	7,594	8,480
Drug Product Revenue [Member] | Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	7,594	4,030
Drug Product Revenue [Member] | AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 0	$ 4,450

Collaboration Agreements, Li_16

Collaboration Agreements, License Agreement and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	$ 4,744		$ 15,857
Drug product revenue recognized	60,827	$ 38,429
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	7,594	8,480
Drug Product Revenue [Member] | Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	7,594	4,030
Drug Product Revenue [Member] | Astra Zeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	0	4,450
Drug Product Revenue [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	9,800
Drug Product Revenue [Member] | API Shipment [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	2,200	$ 4,000
Bulk Drug Product [Member] | Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	45,500
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] | E U Supply And Astellas Agreement [Member] | Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Billed Contracts Receivable	$ 49,200

Variable Interest Entity - Addi

Variable Interest Entity - Additional Information (Detail)	Mar. 31, 2022
Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] | Beijing Falikang Pharmaceutical Co Ltd | FibroGen Beijing [Member] | AstraZenecaAB [Member]
Acquisition And Variable Interest Entity [Line Items]
Percentage of outstanding shares acquired	51.10%

Variable Interest Entity - Summ

Variable Interest Entity - Summary of Equity Method Investment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Acquisition And Variable Interest Entity [Line Items]
Beginning balance	$ 3,825
Share of Net Income	320	$ (240)
Ending balance	$ 4,155
Beijing Falikang Pharmaceutical Co. Ltd [Member]
Acquisition And Variable Interest Entity [Line Items]
Ownership Percentage	51.10%
Beginning balance	$ 3,825
Share of Net Income	320
Currency Translation	10
Ending balance	$ 4,155

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 335,667	$ 401,763
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	146,273	182,646
Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	50,357	68,079
Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,660	27,087
Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	4,983	9,154
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	356,127	461,564
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	16,466	58,801
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	146,273	182,646
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	54,351	69,079
Fair Value, Measurements, Recurring [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	98,376	91,522
Fair Value, Measurements, Recurring [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	23,018	23,275
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,660	27,087
Fair Value, Measurements, Recurring [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	4,983	9,154
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	114,842	150,323
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	16,466	58,801
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	98,376	91,522
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	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	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	241,285	311,241
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	146,273	182,646
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	54,351	69,079
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	0	0
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	23,018	23,275
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	12,660	27,087
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	4,983	9,154
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	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	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	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2022USD ($)
Fair Value Disclosures [Abstract]
Transfers of assets from level 1 to 2	$ 0
Transfers of assets from level 2 to 1	0
Transfers of assets into level 3	0
Transfers of assets out of level 3	$ 0

Leases - Schedule of Lease Asse

Leases - Schedule of Lease Assets and Related Lease Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease right-of-use assets, net	$ 87,990	$ 91,112
Operating lease liabilities	10,978	10,944
Operating lease liabilities	$ 85,948	$ 88,776

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Lessee Lease Description [Line Items]
Operating lease right-of-use assets	$ 87,990	$ 91,112
Operating lease liability	$ 96,900

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Finance lease cost:
Amortization of right-of-use assets	$ 134	$ 2,616

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows from finance leases	$ 1	$ 3,299

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Detail) $ in Millions	Mar. 31, 2022USD ($)
Operating Leases
Present value of lease liabilities	$ 96.9

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Cash And Cash Equivalents [Abstract]
Cash	$ 165,436	$ 111,422
Commercial paper	3,994	1,000
Money market funds	16,466	58,801
Total cash and cash equivalents	$ 185,896	$ 171,223

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Jul. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 185,896,000	$ 171,223,000
Other-than-temporary impairment loss	0
API and bulk drug product price true-up	60,834,000
Acquired In Process Research And Development Asset		35,000,000
Profit share liability	$ 4,744,000	$ 15,857,000
Eluminex [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled upfront payment			$ 8,000,000
U.S. [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage of pre-launch inventory capitalized of aggregate inventory balance	51.00%	38.00%
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Contractual maturities of available-for-sale investments	2 years
Foreign subsidiaries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 95,200,000	$ 91,200,000

Balance Sheet Components - Summ

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	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 339,159	$ 402,664
Gross Unrealized Holding Gains	0	2
Gross Unrealized Holding Losses	(3,492)	(903)
Fair Value	335,667	401,763
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	148,022	183,136
Gross Unrealized Holding Gains	0	2
Gross Unrealized Holding Losses	(1,749)	(492)
Fair Value	146,273	182,646
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	50,357	68,079
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Fair Value	50,357	68,079
U.S. government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	99,764	91,840
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(1,388)	(318)
Fair Value	98,376	91,522
Agency bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,279	23,339
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(261)	(64)
Fair Value	23,018	23,275
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,693	27,105
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(33)	(18)
Fair Value	12,660	27,087
Foreign government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,044	9,165
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	(61)	(11)
Fair Value	$ 4,983	$ 9,154

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule Of Investments [Abstract]
Raw materials	$ 1,359	$ 1,363
Work-in-progress	33,837	21,499
Finished goods	7,871	8,153
Total inventories	$ 43,067	$ 31,015

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 65,112	$ 56,283
API and bulk drug product price true-up	60,834
Acquired in-process research and development asset		35,000
Payroll and related accruals	12,325	20,909
Contract liabilities to pharmaceutical distributors	2,759	3,176
Accrued co-promotion expenses - current	28,117	25,746
Roxadustat profit share to AstraZeneca	7,917	7,895
Property taxes and other taxes	13,928	12,610
Professional services	6,819	6,074
Other	5,488	4,906
Total accrued and other current liabilities	$ 203,299	$ 172,599

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Related Party Transaction [Line Items]
Accounts Receivable Related Parties Current	$ 38,755		$ 10,930
Accrued liabilities to related party	49,677		4
Investment income (loss)	(320)	$ 240
Equity method investments	4,155		3,825
Astellas [Member]
Related Party Transaction [Line Items]
Drug product revenue from a related party	7,600	4,000
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	27,800	3,600
Accounts Receivable Related Parties Current	37,600		10,900
Accrued liabilities to related party	49,700
Contract With Customer Liability	29,600		27,900
Falikang [Member]
Related Party Transaction [Line Items]
Accounts Receivable Related Parties Current	1,200		0
Investment income (loss)	300	(200)
Equity method investments	$ 4,200		3,800
Percentage of outstanding shares owned	51.10%
Deferred revenue	$ 0		$ 1,200
Falikang [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	$ 16,200	$ 10,400

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	1 Months Ended		3 Months Ended
	May 31, 2021PutativeClassAction	Apr. 30, 2021PutativeClassAction	Mar. 31, 2022USD ($)
Commitments And Contingencies [Line Items]
Operating lease liability			$ 96.9
Outstanding non-cancelable purchase obligations			56.9
Putative securities class action complaints filed | PutativeClassAction	2	3
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations			12.2
Manufacture and Supply of Pamrevlumab [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations			34.2
Other Purchases [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations			10.5
Research and Pre-Clinical Stage Development Programs [Member]
Commitments And Contingencies [Line Items]
Maximum future milestone payments			$ 704.1