FibroGen (FGEN) 10-Q 9 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 31, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	FGEN
Entity Registrant Name	FIBROGEN, INC.
Entity Central Index Key	0000921299
Current Fiscal Year End Date	--12-31
Entity Filer Category	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		92,621,941

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 353,361	$ 678,393
Short-term investments	153,851	8,144
Accounts receivable, net ($13,352 and $4,127 from related parties)	24,266	41,883
Inventories	24,530	16,530
Prepaid expenses and other current assets ($0 and $889 from related parties)	8,458	10,160
Total current assets	564,466	755,110
Restricted time deposits	2,072	2,072
Long-term investments	105,758	244
Property and equipment, net	30,670	33,647
Finance lease right-of-use assets	861	29,606
Equity method investment in unconsolidated variable interest entity	3,083	2,728
Operating lease right-of-use assets	97,091	2,043
Other assets	4,617	1,390
Total assets	808,618	826,840
Current liabilities:
Accounts payable ($0 and $1,118 to a related party)	48,988	24,789
Accrued and other current liabilities ($14 and $24 to a related party)	147,801	118,333
Deferred revenue ($10,699 and $2,907 to a related party)	25,234	6,547
Finance lease liabilities, current	23	12,330
Operating lease liabilities, current	10,718	1,188
Total current liabilities	232,764	163,187
Product development obligations	18,277	18,697
Deferred revenue, net of current ($9,381 and $4,636 to a related party)	152,865	138,474
Finance lease liabilities, non-current	6	25,391
Operating lease liabilities, non-current	94,196	853
Other long-term liabilities	30,659	38,789
Total liabilities	528,767	385,391
Commitments and Contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at June 30, 2021, and December 31, 2020	0	0
Common stock, $0.01 par value; 225,000 shares authorized at June 30, 2021, and December 31, 2020; 92,609 and 91,441 shares issued and outstanding at June 30, 2021, and December 31, 2020	926	914
Additional paid-in capital	1,443,975	1,399,774
Accumulated other comprehensive loss	(4,567)	(4,499)
Accumulated deficit	(1,179,754)	(974,011)
Total stockholders’ equity	260,580	422,178
Non-controlling interests	19,271	19,271
Total equity	279,851	441,449
Total liabilities, stockholders’ equity and non-controlling interests	$ 808,618	$ 826,840

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Accounts receivable from related parties	$ 13,352	$ 4,127
Prepaid expenses and other current assets from related parties	0	889
Accounts payable to related party	0	1,118
Accrued and other current liabilities to related party	14	24
Deferred revenue current to related party	10,699	2,907
Deferred revenue non-current to related party	$ 9,381	$ 4,636
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	125,000,000	125,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	92,609,000	91,441,000
Common stock, shares outstanding	92,609,000	91,441,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Total revenue	$ 24,364	$ 42,888	$ 62,793	$ 67,288
Operating costs and expenses:
Cost of goods sold	$ 3,078	$ 3,076	$ 6,479	$ 4,047
Cost, Product and Service [Extensible List]	Product Revenue, Net [Member]	Product Revenue, Net [Member]	Product Revenue, Net [Member]	Product Revenue, Net [Member]
Research and development	$ 122,567	$ 61,414	$ 197,243	$ 116,315
Selling, general and administrative	32,554	63,535	63,334	113,138
Total operating costs and expenses	158,199	128,025	267,056	233,500
Loss from operations	(133,835)	(85,137)	(204,263)	(166,212)
Interest and other, net
Interest expense	(355)	(651)	(856)	(1,284)
Interest income and other income (expenses), net	(363)	644	(817)	3,810
Total interest and other, net	(718)	(7)	(1,673)	2,526
Loss before income taxes	(134,553)	(85,144)	(205,936)	(163,686)
Provision for (benefit from) income taxes	(3)	169	130	(25)
Investment income in unconsolidated variable interest entity	562	0	323	0
Net loss	$ (133,988)	$ (85,313)	$ (205,743)	$ (163,661)
Net loss per share - basic and diluted	$ (1.45)	$ (0.95)	$ (2.24)	$ (1.84)
Weighted average number of common shares used to calculate net loss per share - basic and diluted	92,276	89,451	91,983	88,835
License Revenue [Member]
Revenue:
Total revenue	$ 0	$ 0	$ 0	$ 0
Development and Other Revenue [Member]
Revenue:
Total revenue	19,641	18,957	34,228	38,402
Product Revenue, Net [Member]
Revenue:
Total revenue	13,371	15,693	28,733	20,648
Drug Product Revenue [Member]
Revenue:
Total revenue	$ (8,648)	$ 8,238	$ (168)	$ 8,238

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - Astellas Agreement [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Collaboration services and other revenue from a related party	$ 2,645	$ 4,766	$ 6,256	$ 9,503
Product revenue from a related party	11,760	0	22,167	0
Drug product revenue from a related party	$ (1,974)	$ 8,238	$ 2,056	$ 8,238

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (133,988)	$ (85,313)	$ (205,743)	$ (163,661)
Other comprehensive income (loss):
Foreign currency translation adjustments	40	(1,615)	(30)	(1,334)
Available-for-sale investments:
Unrealized gain (loss) on investments, net of tax effect	17	(1,129)	(38)	520
Other comprehensive income, net of taxes	57	(2,744)	(68)	(814)
Comprehensive loss	$ (133,931)	$ (88,057)	$ (205,811)	$ (164,475)

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, 2019	$ 535,406	$ 877	$ 1,300,725	$ (747)	$ (784,720)	$ 19,271
Balance, Shares at Dec. 31, 2019		87,657,489
Net loss	(163,661)	$ 0	0	0	(163,661)	0
Change in unrealized gain or loss on investments	520	0	0	520	0	0
Foreign currency translation adjustments	(1,334)	0	0	(1,334)	0	0
Shares issued from stock plans, net of payroll taxes paid	9,652	$ 25	9,627	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		2,570,804
Stock-based compensation	34,560	$ 0	34,560	0	0	0
Balance at Jun. 30, 2020	415,143	$ 902	1,344,912	(1,561)	(948,381)	19,271
Balance, Shares at Jun. 30, 2020		90,228,293
Balance at Mar. 31, 2020	477,629	$ 889	1,319,354	1,183	(863,068)	19,271
Balance, Shares at Mar. 31, 2020		88,895,630
Net loss	(85,313)	$ 0	0	0	(85,313)	0
Change in unrealized gain or loss on investments	(1,129)	0	0	(1,129)	0	0
Foreign currency translation adjustments	(1,615)	0	0	(1,615)	0	0
Shares issued from stock plans, net of payroll taxes paid	7,927	$ 13	7,914	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		1,332,663
Stock-based compensation	17,644	$ 0	17,644	0	0	0
Balance at Jun. 30, 2020	415,143	$ 902	1,344,912	(1,561)	(948,381)	19,271
Balance, Shares at Jun. 30, 2020		90,228,293
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 loss	(205,743)	$ 0	0	0	(205,743)	0
Change in unrealized gain or loss on investments	(38)	0	0	(38)	0	0
Foreign currency translation adjustments	(30)	0	0	(30)	0	0
Shares issued from stock plans, net of payroll taxes paid	5,828	$ 12	5,816	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		1,168,296
Stock-based compensation	38,385	$ 0	38,385	0	0	0
Balance at Jun. 30, 2021	279,851	$ 926	1,443,975	(4,567)	(1,179,754)	19,271
Balance, Shares at Jun. 30, 2021		92,608,929
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
Net loss	(133,988)	$ 0	0	0	(133,988)	0
Change in unrealized gain or loss on investments	17	0	0	17	0	0
Foreign currency translation adjustments	40	0	0	40	0	0
Shares issued from stock plans, net of payroll taxes paid	4,508	$ 5	4,503	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		528,530
Stock-based compensation	19,001	$ 0	19,001	0	0	0
Balance at Jun. 30, 2021	$ 279,851	$ 926	$ 1,443,975	$ (4,567)	$ (1,179,754)	$ 19,271
Balance, Shares at Jun. 30, 2021		92,608,929

Condensed Consolidated Statem_5

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities
Net loss	$ (205,743)	$ (163,661)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	5,242	5,737
Amortization of finance lease right-of-use assets	4,393	5,247
Net accretion of premium and discount on investments	767	(22)
Unrealized loss on equity investments	4	15
Investment loss in unconsolidated variable interest entity	(323)	0
Loss (gain) on disposal of property and equipment	13	0
Stock-based compensation	38,385	34,560
Expense for acquired in-process research and development asset	25,000	0
Tax benefit on unrealized gain on available-for-sale securities	0	(138)
Realized loss on sales of available-for-sale securities	8	258
Changes in operating assets and liabilities:
Accounts receivable, net	17,868	1,903
Inventories	(7,861)	(2,016)
Prepaid expenses and other current assets	2,231	126,874
Operating lease right-of-use assets	(1,800)	494
Other assets	(3,066)	3,529
Accounts payable	(1,013)	(1,060)
Accrued and other liabilities	27,745	(33,331)
Operating lease liabilities, current	295	(170)
Deferred revenue	33,078	48,117
Accrued interest for finance lease liabilities	(73)	(115)
Operating lease liabilities, non-current	1,388	(359)
Other long-term liabilities	(8,065)	64,317
Net cash provided by (used in) operating activities	(71,527)	90,179
Investing activities
Purchases of property and equipment	(2,215)	(1,185)
Payment made for investment in unconsolidated variable interest entity	0	(1,419)
Purchases of available-for-sale securities	(266,647)	(38)
Proceeds from sales of available-for-sale securities	4,000	10,606
Proceeds from maturities of investments	10,610	201,900
Net cash provided by (used in) investing activities	(254,252)	209,864
Financing activities
Repayments of finance lease liabilities	(5,326)	(5,992)
Repayments of lease obligations	(201)	(201)
Cash paid for payroll taxes on restricted stock unit releases	(5,928)	(6,858)
Proceeds from issuance of common stock	11,756	16,510
Net cash provided by financing activities	301	3,459
Effect of exchange rate change on cash and cash equivalents	446	(499)
Net increase (decrease) in cash and cash equivalents	(325,032)	303,003
Total cash and cash equivalents at beginning of period	678,393	126,266
Total cash and cash equivalents at end of period	$ 353,361	$ 429,269

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
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, connective tissue growth factor (“CTGF”) biology, and clinical development to advance innovative medicines for the treatment of anemia, fibrotic disease, and cancer. Roxadustat, FibroGen’s most advanced product, is an oral small molecule inhibitor of HIF prolyl hydroxylase (“HIF-PH”) activity that is being commercialized in China (tradename: 爱瑞卓 ® ® In June 2021, the Committee for Medicinal Products for Human Use of the European Medicines Agency (“EMA”) adopted a positive opinion, recommending the granting of Marketing Authorization Application (“MAA”) for the medicinal product Evrenzo (roxadustat), intended for the treatment of adult patients with symptomatic anemia associated with CKD. Our partner Astellas Pharma Inc. (“Astellas”) expects an approval decision on the MAA for roxadustat by the European Commission in August 2021. In July 2021, the United States (“U.S.”) Food and Drug Administration (“FDA”) Cardiovascular and Renal Drugs Advisory Committee (“CRDAC”) voted to recommend not approving roxadustat, an oral HIF-PH inhibitor, for the treatment of anemia due to CKD in adult patients. The CRDAC vote was 13 to 1 for non-dialysis dependent CKD patients, and 12 to 2 for dialysis-dependent CKD patients. While the FDA is not required to follow CRDAC's vote, the agency considers CRDAC's non-binding recommendations when making its decision. Roxadustat is in Phase 3 clinical development in the U.S. and Europe and in Phase 3 development in China for anemia associated with myelodysplastic syndromes. Roxadustat is in Phase 2 clinical development for chemotherapy-induced anemia. Pamrevlumab, a human monoclonal antibody targeting CTGF, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, locally advanced unresectable pancreatic cancer and Duchenne muscular dystrophy. 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 for which FibroGen is not the primary beneficiary, the Company uses the equity method of accounting. The Company operates as one 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 U.S. (“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 filed with the SEC for the year ended December 31, 2020 (“2020 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 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. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units and shares to be purchased under the employee stock purchase plan totaling 11.4 million and 9.2 million for the three months ended June 30, 2021 and 2020, and totaling 9.4 million and 9.0 million for the six months ended June 30, 2021 and 2020, respectively, as they were anti-dilutive. Risks and Uncertainties The Company’s business is subject to risks and uncertainties, including those related to Severe Acute Respiratory Syndrome Coronavirus 2 and the resulting Coronavirus Disease (“COVID-19”) and the risk that we may not get approval of roxadustat in the U.S. for CKD anemia given the fact that the CRDAC voted to recommend not approving roxadustat in July 2021. 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 FDA or other regulatory authorities, Recently Issued and Adopted Accounting Guidance In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes 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 ” , Reference Rate Reform (Topic 848): Scope The Company has certain lease arrangements that are linked to 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 period ended June 30, 2021 and is currently evaluating the impact on its consolidated financial statements and related disclosures upon adoption of this guidance. 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 2020 Form 10-K, except for the following: Product revenue, net Product revenue, net consists of revenues from sales of roxadustat commercial product to Beijing Falikang Pharmaceutical Co., Ltd. (“Falikang”), and directly to pharmaceutical distributors located in a few provinces in China that are not covered by Falikang. Falikang is jointly owned by AstraZeneca AB (“AstraZeneca”) and FibroGen Beijing. The Company is not the primary beneficiary of Falikang for accounting purposes, as AstraZeneca is the final decision maker for all the roxadustat commercialization activities, and the Company lacks the power criterion to direct the activities of Falikang (see Note 3, Variable Interest Entity Sales to Falikang Falikang became fully operational in January 2021, at which time FibroGen Beijing began selling roxadustat commercial product to Falikang. Falikang is FibroGen Beijing’s primary customer in China and substantially all roxadustat product sales to distributors in China are made by Falikang. Falikang bears inventory risk once it receives and accepts the product from FibroGen Beijing, and is responsible for delivering product to its distributors. The promises identified under the AstraZeneca China Agreement (as defined in Note 2, Collaboration Agreements and Revenues Collaboration Agreements and Revenues, The initiation of roxadustat sales to Falikang marked the beginning of the China performance obligation . Revenue is recognized at a point in time when control of roxadustat commercial product is transferred to Falikang. Revenue is recognized based on the estimated transaction price per unit and actual quantity of product delivered during the reporting period. Specifically, the transaction price per unit is determined based on the overall transaction price over the total estimated sales quantity for the estimated performance period in which the Company believes those sales would occur. The price per unit is subject to reassessment on a quarterly basis, which may result in cumulative catch up adjustments due to changes in estimates. The overall transaction price for FibroGen Beijing’s product sales to Falikang includes the following elements of consideration: ● ● ● Interim profit/loss share between FibroGen Beijing and AstraZeneca from April 1, 2020 through December 31, 2020; and ● o o The non-refundable upfront license fees constitute a fixed consideration. The remainder of the above are variable consideration components, which may be constrained, and included in the transaction price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period when the uncertainty associated with the variable consideration is subsequently resolved. The calculation of the above variable consideration includes key estimates such as total sales quantity, performance period, gross transfer price and profit share, which require a substantial degree of judgment. Any net transfer price in excess of the revenue recognized is deferred, and will be recognized over future periods as the performance obligations are satisfied. Direct Sales to Distributors The Company sells roxadustat in China directly to a number of pharmaceutical distributors located in a few provinces in China that are not covered by Falikang. These pharmaceutical distributors are the Company’s customers. Hospitals order roxadustat through a distributor and the Company ships the product directly to the distributors. The delivery of roxadustat to a distributor represents a single performance obligation. Distributors are responsible for delivering product to end users, primarily hospitals. Distributors bear inventory risk once they receive and accept the product. Product revenue is recognized when control of the promised good is transferred to the customer in an amount that reflects the consideration to which the Company expects to be entitled to in exchange for the product. The period between the transfer of control of the promised goods and when the Company receives payment is based on 60-day payment terms. As such, product revenue is not adjusted for the effects of a significant financing component. Product revenue is recorded at the net sales prices which includes the following estimates of variable consideration: ● ● ● Revenue from Contracts with Customers ● Other discounts and rebates, including key account hospital sales reba t e and transfer fee discount, are generally based on a percentage of eligible gross sales made by the distributor and recorded as a reduction to revenue at the point of sale to the distributor; and ● The calculation of the above variable consideration is based on gross sales to the distributor, or estimated utilizing best available information from the distributor, maximum known exposures and other available information including estimated channel inventory levels and estimated sales made by the distributor to hospitals, which involve a substantial degree of judgment. The above rebates and discounts all together are eligible to be applied against the distributor’s future sales order, limited to certain maximums until such rebates and discounts are exhausted. These rebates and discounts are recorded as contract liabilities at the time they become eligible and in the same period that the related revenue is recorded. Due to the distributor’s legal right to offset, at each balance sheet date, the liability for rebates and discounts are presented as reductions of 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 distributor’s legal right of offset is calculated at the individual distributor level. License Acquisition Agreement On June 16, 2021, the Company entered into an exclusive license and option agreement with HiFiBiO Therapeutics (“HiFiBiO”) (“HiFiBiO Agreement”), pursuant to which the Company exclusively licensed all product candidates in HiFiBiO’s Galectin-9 program and will have the sole right to develop them worldwide. The Company has also obtained exclusive options to license all product candidates in HiFiBiO’s CXCR5 and CCR8 programs. Under the terms of the HiFiBiO Agreement, the Company will make a $25 million upfront payment to HiFiBiO, as well as payments upon option exercise. In addition, HiFiBiO may receive up to a total of an additional $1.1 billion in future option, clinical, regulatory, and commercial milestone payments across all three programs. HiFiBiO will also be eligible to receive royalties based upon worldwide net sales. The acquisition of these licenses was accounted for as an asset acquisition. The initial upfront payment of $25.0 million related to the license and options acquisition meets the definition of an in-process research and development asset (“IPR&D asset”) under the ASC 730, Research and Development Contingent consideration payments will be evaluated and recognized when they become probable and reasonably estimable. The related IPR&D asset will only be capitalized if it has an alternative future use other than in a particular research and development project. Otherwise, amounts allocated to IPR&D asset that have no alternative use will be expensed. As of June 30, 2021, all programs were at the early stage of development and the contingencies related to the milestone payments had not been resolved, therefore no contingent consideration was recognized. The Company will reassess the probability of future option payments and contingent payments on a quarterly basis.

Collaboration Agreements and Re

Collaboration Agreements and Revenues	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements and Revenues	2 . Collaboration Agreements and Revenues Astellas Agreements Japan Agreement In June 2005, the Company entered into a collaboration agreement with Astellas for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). Under the Japan Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $132.5 million in potential milestone payments, comprised of (i) up to $22.5 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of July 2016), (ii) up to $95.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $15.0 million in milestone payments upon the achievement of specified commercial sales milestone. 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 June 30, 2021 totals $105.1 million, excluding drug product revenue that is discussed separately below. 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”). Under this amendment, FibroGen would continue to manufacture and supply roxadustat active pharmaceutical ingredient (“ API ”) to Astellas for the roxadustat commercial purposes in Japan . The commercial terms of the Japan Agreement relating to the transfer price for roxadustat for commercial use remain substantially the same, reflecting an adjustment for the manufacture of drug product by Astellas rather than FibroGen. The related drug product revenue, as described in details under Drug Product Revenue section below, was $ (2.0) million and $ 2.1 million for the three and six months ended June 30 , 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 paid license fees and other upfront consideration totaling $320.0 million (such amounts were fully received as of February 2009). The Europe Agreement also provides for additional development and regulatory approval milestone payments up to $425.0 million, comprised of (i) up to $90.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of 2012), (ii) up to $335.0 million in milestone payments upon achievement of specified regulatory milestone events. Under 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. The aggregate amount of consideration received under the Europe Agreement through June 30, 2021 totals $540.0 million, excluding drug product revenue that is discussed separately below. 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 Astellas EU Supply Agreement (“EU Supply Agreement”) under the Europe Agreement with Astellas to define general forecast, order, supply and payment terms for Astellas to purchase roxadustat bulk drug product from FibroGen in support of commercial supplies. The Company shipped bulk drug product to Astellas as pre-commercial supply for process validation purposes during the first quarter of 2021. The Company recorded the consideration of $11.8 million from this shipment as deferred revenue as of June 30, 2021, as described in details under Drug Product Revenue 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 paid upfront, non-contingent, non-refundable and time-based payments totaling $374.0 million (such amounts were fully received as of June 2016). Under the U.S./RoW Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $875.0 million in potential milestone payments, comprised of (i) up to $65.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of April 2020), (ii) up to $325.0 million in milestone payments upon achievement of specified regulatory milestone events, (iii) up to $160.0 million in milestone payments related to activity by potential competitors and (iv) up to approximately $325.0 million in milestone payments upon the achievement of specified commercial sales events. The aggregate amount of consideration received under the U.S./RoW Agreement through June 30, 2021 totals $439.0 million, excluding drug product revenue that is discussed separately below. 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. The Company shipped bulk drug product to AstraZeneca as commercial supply during 2020, and the first and second quarter of 2021. On July 15, 2021, the FDA CRDAC voted to recommend not approving roxadustat for the treatment of anemia due to CKD in adult patients. While the FDA is not required to follow the CRDAC’s vote, the agency considers the CRDAC’s non-binding recommendations when making its decision. The Company evaluated the impact of these developments in revising its estimates of variable consideration associated with drug product revenue. As a result, the Company updated the estimated transaction price, and recorded $11.2 million as deferred revenue as of June 30, 2021. See details under Drug Product Revenue 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 totaling $28.2 million (such amounts were fully received in 2014). Under the China Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $348.5 million in potential milestone payments, comprised of (i) up to $15.0 million in milestone payments upon achievement of specified clinical and development milestone events, (ii) up to $146.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $187.5 million in milestone payments upon the achievement of specified commercial sales and other events. 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 the third quarter of 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 June 30, 2021 totals $77.2 million. China Amendment In July 2020, FibroGen China and AstraZeneca (together with FibroGen China, the “Parties”) entered into the China Amendment, effective July 1, 2020, relating to the development and commercialization of roxadustat in China. While the responsibilities of the Parties under the China Agreement remain largely the same, certain changes were made. Under the China Amendment, in September 2020, FibroGen Beijing and AstraZeneca completed the establishment of a jointly owned entity, Falikang, which performs roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. Under the China Amendment, the interim period is defined as the period from April 1, 2020 to the time when Falikang is fully operational. Falikang became fully operational in January 2021. The calculation for profit or loss share related to sales of roxadustat in China has changed for the period from April 1, 2020 onwards. With effect from April 1, 2020, the Parties have changed the method under which commercial expenses incurred by AstraZeneca are calculated and billed. AstraZeneca’s co-promotion expenses for their sales and marketing efforts are now subject to a cap of a percentage of net sales. Once AstraZeneca has been fully reimbursed for their sales and marketing costs under the cap, AstraZeneca will bill the co-promotion expenses based on actual costs on a prospective basis. In addition, the China Amendment has allowed for a higher cost of manufacturing incurred by FibroGen Beijing to be included in the profit or loss share calculation, subject to an annual cap, among other changes. 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 a few provinces 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. In addition, AstraZeneca now bills the co-promotion expenses to Falikang and to FibroGen Beijing, respectively, for its services provided to the respective entity. Development costs continue to be shared 50/50 between the Parties. During the three and six months ended June 30, 2021, the Company recognized $11.8 million and $22.2 million, respectively, of net product revenue from the sales to Falikang, as described in details under Product Revenue, Net In addition to sales to Falikang, during the three and six months ended June 30, 2021, the Company recognized $1.6 million and 6.6 million, respectively, of net product revenue from sales directly to distributors in a few provinces in China, as Product Revenue, Net License Revenue and Development Revenue Recognized Under the Collaboration Agreements Amounts recognized as license revenue and development revenue under the Japan Agreement with Astellas were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2021 2020 2021 2020 Japan License revenue $ — $ — $ — $ — Development revenue $ 99 $ 164 $ 179 $ 327 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 Revenue Through June 30, 2021 Deferred Revenue at June 30, 2021 Total Consideration Through June 30, 2021 License $ 100,347 $ — $ 100,347 Development revenue 16,529 30 16,559 Total license and development revenue $ 116,876 $ 30 $ 116,906 The revenue recognized under the Japan Agreement for the three months ended June 30, 2021 included immaterial revenue resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods. The Company does not expect material variable consideration from estimated future co-development billing beyond the development period in the transaction price related to the Japan Agreement. Amounts recognized as license revenue and development revenue under the Europe Agreement with Astellas were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2021 2020 2021 2020 Europe License revenue $ — $ — $ — $ — Development revenue $ 2,546 $ 4,602 $ 6,077 $ 9,176 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 Revenue Through June 30, 2021 Deferred Revenue at June 30, 2021 Total Consideration Through June 30, 2021 License $ 487,951 $ — $ 487,951 Development revenue 255,039 333 255,372 Total license and development revenue $ 742,990 $ 333 $ 743,323 The revenue recognized under the Europe Agreement for the three months ended June 30, 2021 included an increase in revenue of $0.4 million resulting from changes to estimated variable consideration. The remainder of the transaction price related to the Europe Agreement includes $10.7 million of variable consideration from estimated future co-development billing and is expected to be recognized over the remaining development service period. Amounts recognized as revenue under the U.S./RoW and China Agreement with AstraZeneca were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2021 2020 2021 2020 U.S. / RoW and China License revenue $ — $ — $ — $ — Development revenue 16,993 13,750 27,969 28,305 China performance obligation $ — $ 441 $ — $ 594 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 Revenue Through June 30, 2021 Deferred Revenue at June 30, 2021 Total Consideration Through June 30, 2021 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 582,743 2,309 585,052 China performance obligation * 22,167 149,759 171,926 Total license and development revenue $ 946,754 $ 152,068 ** $ 1,098,822 * China performance obligation revenue is recognized as product revenue, as described in details under Product Revenue, Net ** Contract assets and liabilities related to rights and obligations in the same contract are recorded net on the consolidated balance sheets. As of June 30, 2021, deferred revenue included $146.8 million related to the U.S./RoW and China Agreement, which represents the net of $152.1 million of deferred revenue presented above and a $5.3 million unbilled co-development revenue under the China Amendment with AstraZeneca. The revenue recognized under the U.S./RoW Agreement for the three months ended June 30, 2021 included a reduction in revenue of $0.2 million resulting from changes to estimated variable consideration. The remainder of the transaction price related to the U.S./RoW Agreement and China Agreement includes $34.1 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 U.S./RoW Agreement is expected to be recognized over the remaining development service period. The amount allocated to the China performance obligation is expected to be recognized as the Company transfers control of the commercial products to Falikang. Product Revenue, Net Product revenue, net from the sales of roxadustat commercial product in China was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Direct Sales: Gross revenue $ 2,230 $ 19,833 $ 7,659 $ 25,205 Discounts and rebates (618 ) (4,095 ) (1,181 ) (4,512 ) Sales returns (1 ) (45 ) 88 (45 ) Direct sales revenue, net 1,611 15,693 6,566 20,648 Sales to Falikang: Gross transfer price 26,714 — 51,115 — Profit share (9,573 ) — (19,636 ) — Net transfer price 17,141 — 31,479 Increase in deferred revenue (5,381 ) — (9,312 ) Sales to Falikang revenue, net 11,760 — 22,167 — Total product revenue, net $ 13,371 $ 15,693 $ 28,733 $ 20,648 Direct Sales Product revenue from direct roxadustat product sales to distributors in China is recognized in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those products, net of various sales rebates and discounts. The total discounts and rebates were $0.6 million and $4.1 million for the three months ended June 30, 2021 and 2020, and $1.2 million and $4.5 million for the six months ended June 30, 2021 and 2020, respectively, which primarily consisted of the contractual sales rebate calculated based on the stated percentage of gross sales by each distributor in the distribution agreement entered between FibroGen and each distributor. The rebates and discounts that the Company’s pharmaceutical distributors have earned are eligible to be applied against future sales orders, limited to certain maximums until such rebates and discounts are exhausted. These rebates and discounts are recorded as contract liabilities at the time they become eligible in the same period that the related revenue is recorded. 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 December 31, 2020 Additions Deduction Currency Translation and Other Balance at June 30, 2021 Product revenue - Direct sales - contract liabilities $ (15,137 ) $ (883 ) $ 2,410 $ (183 ) $ (13,793 ) As of June 30, 2021 and December 31, 2020, the total contract liabilities were $13.8 million and $15.1 million, which 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 was $0.8 million and $0.5 million as of June 30, 2021 and December 31, 2020, 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 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 transfer 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 obligations are satisfied . During the three and six months ended June 30, 2021, following updates to its estimates, the Company deferred $5.4 million and $9.3 million, respectively, from the net transfer price to Falikang, which was included in the related deferred revenue of the China performance obligation. The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands): Balance at December 31, 2020 Additions Recognized as Revenue Balance at June 30, 2021 Product revenue - AstraZeneca China performance obligation - deferred revenue $ (137,338 ) $ (34,588 ) $ 22,167 $ (149,759 ) 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 June 30, 2021, approximately $6.3 million of the 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. The reductions to gross accounts receivable related to product revenue to Falikang was $10.1 million as of June 30, 2021. Drug Product Revenue Drug product revenue from commercial-grade API or bulk drug product sales to AstraZeneca and Astellas was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Astellas $ (1,974 ) $ 8,238 $ 2,056 $ 8,238 AstraZeneca (6,674 ) — (2,224 ) — Drug product revenue $ (8,648 ) $ 8,238 $ (168 ) $ 8,238 During three months ended June 30, 2021, the Company shipped bulk drug product to AstraZeneca as commercial supply under the terms of the Master Supply Agreement. Based on the above-mentioned FDA CRDAC’s vote on July 15, 2021, the Company evaluated the impact of these developments in revising its estimates of variable consideration associated with drug product revenue. As a result, the Company updated the estimated transaction price, and recorded $11.2 million as deferred revenue as of June 30, 2021. During the three months ended June 30, 2021, the Company recorded a reduction of $2.0 million to the drug product revenue related to the API shipments fulfilled under the terms of the Japan Amendment with Astellas in 2018, due to a change in estimated variable consideration. Specifically, the change in estimated variable consideration was based on the API held by Astellas at June 30, 2021, 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. This amount was recorded under deferred revenue in the condensed consolidated balance sheet as of June 30, 2021. During the first quarter of 2021, the Company recorded $4.0 million drug product revenue related to the same API shipments for the change in estimated variable consideration based on the API held by Astellas at March 31, 2021, under the same methodology. This amount was unbilled to Astellas as of March 31, 2021, and was billed and received from Astellas during the second quarter of 2021. During the three months ended March 31, 2021, the Company shipped bulk drug product from process validation supplies for commercial purposes under the terms of the Europe Agreement and the EU Supply Agreement with Astellas. The Company recorded the consideration of $11.8 million from this shipment as deferred revenue as of June 30, 2021, due to a high degree of uncertainty associated with the final consideration. The deferred revenue will be recognized as and when uncertainty is resolved. The following table includes a roll-forward of the above-mentioned deferred revenues that are considered as contract liabilities related to drug product (in thousands): Balance at December 31, 2020 Additions Recognized as Revenue Balance at June 30, 2021 Astellas - Japan Agreement $ — $ (1,974 ) $ — $ (1,974 ) Astellas - Europe Agreement (5,984 ) (11,759 ) — (17,743 ) AstraZeneca - U.S. Agreement — (11,171 ) — (11,171 ) Drug product revenue - deferred revenue $ (5,984 ) $ (24,904 ) $ — $ (30,888 )

Variable Interest Entity

Variable Interest Entity	6 Months Ended
	Jun. 30, 2021
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 The Company’s equity method investment in Falikang was as follows (in thousands): Entity Ownership Percentage Balance at December 31, 2020 Share of Net Income Currency Translation Balance at June 30, 2021 Falikang 51.1 % $ 2,728 $ 323 $ 32 $ 3,083 Falikang is considered a related party to the Company. See Note 9, Related Party Transactions

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
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): June 30, 2021 Level 1 Level 2 Level 3 Total Money market funds $ 220,627 $ — $ — $ 220,627 Corporate bonds — 104,483 — 104,483 Commercial paper — 72,099 — 72,099 U.S. government bonds 46,568 — — 46,568 Agency bonds — 14,284 — 14,284 Asset-backed securities — 12,490 — 12,490 Foreign government bonds — 12,151 — 12,151 Equity investments 233 — — 233 Total $ 267,428 $ 215,507 $ — $ 482,935 December 31, 2020 Level 1 Level 2 Level 3 Total Bond and mutual funds $ — $ 8,144 $ — $ 8,144 Equity investments 244 — — 244 Money market funds 590,347 — — 590,347 Total $ 590,591 $ 8,144 $ — $ 598,735 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 and six months ended June 30, 2021. The Company’s financial liabilities related to lease obligations as of June 30, 2021 and December 31, 2020 were $0.9 million and $1.1 million, respectively. The fair values of the Company’s financial liabilities are carried at historical cost that were derived by using an income approach, which required Level 3 inputs such as discounted estimated future cash flows. There were no transfers of assets or liabilities between levels for any of the periods presented.

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Leases	5. Leases The Company’s lease assets and related lease liabilities were as follows (in thousands): Balance Sheet Line Item June 30, 2021 December 31, 2020 Assets Finance: Right-of-use assets - cost $ 2,007 $ 50,477 Accumulated amortization (1,146 ) (20,871 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 861 29,606 Operating: Right-of-use assets - cost 100,705 3,934 Accumulated amortization (3,614 ) (1,891 ) Operating lease right-of-use assets, net Operating lease right-of-use assets 97,091 2,043 Total lease assets $ 97,952 $ 31,649 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 23 $ 12,330 Operating lease liabilities Operating lease liabilities, current 10,718 1,188 Non-current: Finance lease liabilities Finance lease liabilities, non-current 6 25,391 Operating lease liabilities Operating lease liabilities, non-current 94,196 853 Total lease liabilities $ 104,943 $ 39,762 The Company’s long-term property lease with Alexandria for its corporate headquarters in San Francisco, California, had an initial term of 15 years, scheduled to expire in 2023. The original lease was accounted for as a finance lease upon adoption of ASC 842, Leases On June 1, 2021, the Company entered into an amendment with Alexandria to extend the lease to 2028 (“Lease Amendment”). Under the terms of the Lease Amendment, the Company has two optional rights to each extend the lease for an additional five years. The lease contract provides for a fixed annual rent, with scheduled increases of two percent that occur on each anniversary of the rent commencement date through 2023, and with scheduled increases of three percent that occur on each anniversary of the rent commencement date through 2028. This lease requires the Company to pay all costs of ownership, operation, and maintenance of the premises, including without limitation all operating costs, insurance costs, and taxes. Company determined that the Lease Amendment was a lease modification, effective June 1, 2021, and thus reassessed the lease classification, remeasured the related lease liability using an updated discount rate, and adjusted the related right-of-use asset under the lease modification guidance under the ASC 842. Accordingly, on June 1, 2021, the Company determined that the modified lease be accounted for as an operating lease, and therefore derecognized the previous finance lease right-of-use asset of $24.6 million and the related finance lease liability of $32.6 million, and recognized an operating lease right-of-use asset of $93.2 million and the related operating lease liability of $101.2 million. Starting June 1, 2021, the cash payment related to this lease was classified as an operating activity, the impact of which was approximately $1.1 million to the condensed consolidated statement of cash flow for the six months ended June 30, 2021. During the three months ended March 31, 2021, after FibroGen Beijing’s previous long-term lease agreement expired, the Company entered into a new lease agreement with the landlord for the same pilot plant located in Beijing Yizhuang Biomedical Park of BDA. The new lease term is five year, scheduled to expire in 2026, and is treated as an operating lease. Accordingly, the Company recorded $3.4 million in the operating right-of-use assets and total operating lease liabilities, respectively. The lease contract provides for fixed quarterly rent payments, and require the Company to pay operating and maintenance costs. The components of lease expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Statement of Operations Line Item 2021 2020 2021 2020 Finance lease cost: Amortization of right-of-use assets Cost of goods sold; Research and development; Selling, general and administrative expenses $ 1,777 $ 2,653 $ 4,393 $ 5,247 Interest on lease liabilities Interest expense 242 534 627 1,049 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 1,744 255 2,162 564 Sublease income Selling, general and administrative expenses (275 ) (306 ) (575 ) (598 ) Total lease cost $ 3,488 $ 3,136 $ 6,607 $ 6,262 Supplemental cash flow information related to leases were as follows (in thousands): Six Months Ended June 30, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,246 $ 433 Operating cash flows from finance leases 628 1,010 Financing cash flows from finance leases 5,326 5,992 Non-cash: Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 303 144 Operating leases 3,498 5 Non-cash: Increase (decrease) resulting from lease modification: Finance lease right-of-use assets (24,654 ) — Operating lease right-of-use assets 93,222 — Finance lease liabilities, current (12,587 ) — Operating lease liabilities, current 9,221 — Finance lease liabilities, non-current (20,009 ) — Operating lease liabilities, non-current $ 91,943 $ — Lease term and discount rate were as follows: June 30, 2021 December 31, 2020 Weighted-average remaining lease term (years): Finance leases 1.3 2.9 Operating leases 7.3 1.8 Weighted-average discount rate: Finance leases 4.55 % 4.39 % Operating leases 4.75 % 4.74 % Maturities of lease liabilities as of June 30, 2021 are as follows (in thousands): Year Ending December 31, Finance Leases Operating Leases 2021 (remaining six month period) $ 16 $ 7,534 2022 11 15,517 2023 3 13,454 2024 — 16,798 2025 — 18,193 Beyond 2025 — 53,881 Total future lease payments 30 125,377 Less: Interest (1 ) (20,463 ) Present value of lease liabilities $ 29 $ 104,914

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	6. Balance Sheet Components Cash and Cash Equivalents Cash and cash equivalents consisted of the following (in thousands): June 30, 2021 December 31, 2020 Cash $ 130,035 $ 88,046 Commercial paper 2,699 — Money market funds 220,627 590,347 Total cash and cash equivalents $ 353,361 $ 678,393 At June 30, 2021 and December 31, 2020, a total of $85.1 million and $66.0 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): June 30, 2021 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 104,499 $ 27 $ (43 ) $ 104,483 Commercial paper 69,400 — — 69,400 U.S. government bonds 46,589 — (21 ) 46,568 Agency bonds 14,288 2 (6 ) 14,284 Asset-backed securities 12,489 1 — 12,490 Foreign government bonds 12,151 1 (1 ) 12,151 Equity investments 118 115 — 233 Total investments $ 259,534 $ 146 $ (71 ) $ 259,609 December 31, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Bond and mutual funds $ 8,147 $ — $ (3 ) $ 8,144 Equity investments 125 119 — 244 Total investments $ 8,272 $ 119 $ (3 ) $ 8,388 At June 30, 2021, the available-for-sale investments had contractual maturities range from several months to two years. During the three and six months ended June 30, 2021 and 2020, the Company did not recognize any other-than-temporary impairment loss. Inventories Inventories consisted of the following (in thousands): June 30, 2021 December 31, 2020 Raw materials $ 1,190 $ 2,303 Work-in-progress 15,541 8,114 Finished goods 7,799 6,113 Total inventories $ 24,530 $ 16,530 The Company capitalizes inventory costs for FibroGen Beijing’s production of roxadustat for commercial sales purposes. The Company started capitalizing pre-launch inventory costs in the second quarter of 2020 prior to regulatory approvals in the U.S. and other territories. As of June 30, 2021 and December 31, 2020, pre-launch inventory capitalized was 37% and 29% of the total inventory balance, respectively. The provision to write-down excess and obsolete inventory was immaterial for three and six months ended June 30, 2021 and 2020. Prepaid expenses and other current assets Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2021 December 31, 2020 Unbilled contract assets $ 5,256 $ 2,147 Deferred revenues from associated contracts (5,256 ) (2,147 ) Net unbilled contract assets — — Prepaid assets 7,149 8,353 Other current assets 1,309 1,807 Total prepaid expenses and other current assets $ 8,458 $ 10,160 The unbilled contract assets as of June 30, 2021 of $5.3 million related to unbilled co-development revenue under the China Amendment with AstraZeneca. The unbilled contract assets as of December 31, 2020 were related to unbilled co-development revenue under the China Amendment with AstraZeneca. See Note 2, Collaboration Agreements and Revenues Property and Equipment Property and equipment consisted of the following (in thousands): June 30, 2021 December 31, 2020 Leasehold improvements $ 102,657 $ 102,006 Laboratory equipment 19,247 18,143 Machinery 8,387 8,312 Computer equipment 9,205 9,545 Furniture and fixtures 6,126 6,128 Construction in progress 1,407 760 Total property and equipment $ 147,029 $ 144,894 Less: accumulated depreciation (116,359 ) (111,247 ) Property and equipment, net $ 30,670 $ 33,647 Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following (in thousands): June 30, 2021 December 31, 2020 Preclinical and clinical trial accruals $ 65,274 $ 44,113 Payroll and related accruals 18,047 22,800 Contract liabilities to pharmaceutical distributors 13,793 15,137 Accrued co-promotion expenses - current 20,832 11,537 Roxadustat profit share to AstraZeneca 7,007 7,007 Property taxes and other taxes 10,344 5,970 Professional services 7,471 4,869 Other 5,033 6,900 Total accrued and other current liabilities $ 147,801 $ 118,333 The profit share liability of $7.0 million to AstraZeneca as of June 30, 2021 and December 31, 2020 represented the profit/loss share between FibroGen Beijing and AstraZeneca that was calculated for the interim period pursuant to the China Amendment. This liability correspondingly reduced the deferred revenue related to the performance obligation in accordance with the China Amendment. Other Long-term Liabilities Other long-term liabilities consisted of the following (in thousands): June 30, 2021 December 31, 2020 Accrued long-term co-promotion expenses $ 19,205 $ 27,424 Other long-term tax liabilities 8,985 8,675 Other 2,469 2,690 Total other long-term liabilities $ 30,659 $ 38,789

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	7. Stock-Based Compensation Stock-based compensation expense was recorded directly to research and development and selling, general and administrative expense as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Research and development $ 10,681 $ 10,780 $ 22,903 $ 21,417 Selling, general and administrative 8,320 6,864 15,482 13,143 Total stock-based compensation expense $ 19,001 $ 17,644 $ 38,385 $ 34,560 The assumptions used to estimate the fair value of stock options granted and purchases under the Company’s 2014 Employee Share Purchase Plan (“ESPP”) using the Black-Scholes option valuation model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Stock Options Expected term (in years) 5.6 5.5 5.7 5.7 Expected volatility 63.4 % 69.2 % 59.4 % 68.4 % Risk-free interest rate 0.9 % 0.4 % 0.7 % 0.8 % Expected dividend yield — — — — Weighted average estimated fair value $ 11.91 $ 21.72 $ 25.38 $ 17.75 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Expected volatility 47.5 - 104.2 % 49.5 - 77.1 % 47.5 - 104.2 % 49.5 - 77.1 % Risk-free interest rate 0.0 - 2.2 % 0.2 - 2.9 % 0.0 - 2.2 % 0.2 - 2.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 13.60 $ 17.82 $ 14.69 $ 18.11

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes Provision for (benefit from) income tax for the three and six months ended June 30, 2021 were primarily due to foreign taxes. Provision for (benefit from) income tax for the three and six months ended June 30, 2020 were primarily due to the tax effect arising from other comprehensive income related to available-for-sale securities, and 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	6 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	9. 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 $2.6 million and $4.8 million for the three months ended June 30, 2021 and 2020, and $6.3 million and $9.5 million for the six months ended June 30, 2021 and 2020, respectively. The Company also recorded drug product revenue from Astellas of $(2.0) million and $8.2 million for the three months ended June 30, 2021 and 2020, and $2.1 million and $8.2 million for the six months ended June 30, 2021 and 2020, respectively. See Note 2, Collaboration Agreements and Revenues The Company’s expense related to collaboration agreements with Astellas was immaterial for each of the three and six months ended June 30, 2021 and 2020. As of June 30, 2021 and December 31, 2020, accounts receivable from Astellas were $2.6 million and $4.1 million, respectively. As of June 30, 2021 and December 31, 2020, total deferred revenue from Astellas was $20.1 million and $7.5 million, respectively. As of June 30, 2021, the amount due to Astellas was immaterial. As of December 31, 2020, amount due to Astellas was $1.1 million. Falikang, an entity jointly owned by FibroGen Beijing and AstraZeneca is an unconsolidated VIE accounted for as an equity method investment, and considered as a related party to the Company. FibroGen Beijing owns 51.1% of Falikang’s equity. See Note 3, Variable Interest Entity For the three and six months ended June 30, 2021, the net product revenue from Falikang was $11.8 million and $22.2 million, respectively. See Note 2, Collaboration Agreements and Revenues For the three and six months ended June 30, 2021, the investment income in Falikang was $0.6 million and $0.3 million, respectively. As of June 30, 2021 and December 31, 2020, the Company’s equity method investment in Falikang was $3.1 million and $2.7 million, respectively. See Note 3, Variable Interest Entity As of June 30, 2021, accounts receivable, net, from Falikang was of $10.8 million. As of June 30, 2021, there was no miscellaneous receivables from Falikang. As of December 31, 2020, prepaid expenses and other current assets included miscellaneous receivables from Falikang of $0.9 million.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Contract Obligations As of June 30, 2021, the Company had outstanding total non-cancelable purchase obligations of $81.9 million, including $29.6 million for manufacture and supply of roxadustat, $47.3 million for manufacture and supply of pamrevlumab, and $5.0 million for other purchases. The Company expects to fulfill our 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 June 30, 2021, future milestone payments for research and pre-clinical stage development programs consisted of up to approximately $359.2 million in total potential future milestone payments under the Company’s license agreements with HiFiBiO (for Galectin-9), 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 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 material accruals for any currently active legal action in its condensed consolidated balance sheets as of June 30, 2021, as it 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. Motions for lead plaintiff were filed on June 11, 2021 and a hearing on the motion is scheduled for August 19, 2021. Once a lead plaintiff is appointed by the Court, the Company expects to receive an amended consolidated complaint. 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 the Company’s officers and directors, as well as the Company as nominal defendant, and asserts state and federal claims based on some of the same alleged misstatements as the securities class action complaints. The complaint seeks unspecified damages, attorneys’ fees, and other costs. The Company and individual defendants have not yet 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. 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.

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Event	11. Subsequent Event Outcome of FDA Advisory Committee Review On July 15, 2021, the FDA CRDAC voted to recommend not approving roxadustat for the treatment of anemia due to CKD in adult patients. While the FDA is not required to follow the CRDAC’s vote, the agency considers the CRDAC’s non-binding recommendations when making its decision. The Company evaluated this subsequent event and concluded that it required adjustment and disclosure in the condensed consolidated financial statements, specifically to the drug product revenue related the bulk drug product shipments to AstraZeneca as commercial supply under the terms of the Master Supply Agreement. As a result, the Company recorded $11.2 million as deferred revenue as of June 30, 2021. See Note 2, Collaboration Agreements and Revenues License Agreement with Eluminex On July 19, 2021, Eluminex Biosciences (Suzhou) Limited (“Eluminex”), an ophthalmology-focused biotechnology company headquartered in Suzhou, China with a US-subsidiary office in San Francisco Bay Area, California, exclusively licensed global rights from FibroGen, Inc. for the development and commercialization of an investigational biosynthetic cornea derived from recombinant human collagen Type III intended to treat patients with corneal blindness. Under the terms of the agreement, Eluminex will make an $8 million upfront payment to FibroGen. In addition, FibroGen may receive up to a total of $64 million in future manufacturing, clinical, regulatory, and commercial milestone payments for the biosynthetic cornea program, as well as $36 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 of cornea products, and low single-digit to mid single-digit royalties based upon worldwide net sales of other recombinant human collagen type III products that are not cornea products

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
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, connective tissue growth factor (“CTGF”) biology, and clinical development to advance innovative medicines for the treatment of anemia, fibrotic disease, and cancer. Roxadustat, FibroGen’s most advanced product, is an oral small molecule inhibitor of HIF prolyl hydroxylase (“HIF-PH”) activity that is being commercialized in China (tradename: 爱瑞卓 ® ® In June 2021, the Committee for Medicinal Products for Human Use of the European Medicines Agency (“EMA”) adopted a positive opinion, recommending the granting of Marketing Authorization Application (“MAA”) for the medicinal product Evrenzo (roxadustat), intended for the treatment of adult patients with symptomatic anemia associated with CKD. Our partner Astellas Pharma Inc. (“Astellas”) expects an approval decision on the MAA for roxadustat by the European Commission in August 2021. In July 2021, the United States (“U.S.”) Food and Drug Administration (“FDA”) Cardiovascular and Renal Drugs Advisory Committee (“CRDAC”) voted to recommend not approving roxadustat, an oral HIF-PH inhibitor, for the treatment of anemia due to CKD in adult patients. The CRDAC vote was 13 to 1 for non-dialysis dependent CKD patients, and 12 to 2 for dialysis-dependent CKD patients. While the FDA is not required to follow CRDAC's vote, the agency considers CRDAC's non-binding recommendations when making its decision. Roxadustat is in Phase 3 clinical development in the U.S. and Europe and in Phase 3 development in China for anemia associated with myelodysplastic syndromes. Roxadustat is in Phase 2 clinical development for chemotherapy-induced anemia. Pamrevlumab, a human monoclonal antibody targeting CTGF, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, locally advanced unresectable pancreatic cancer and Duchenne muscular dystrophy.
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 for which FibroGen is not the primary beneficiary, the Company uses the equity method of accounting. The Company operates as one 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 U.S. (“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 filed with the SEC for the year ended December 31, 2020 (“2020 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
Net Income (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. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units and shares to be purchased under the employee stock purchase plan totaling 11.4 million and 9.2 million for the three months ended June 30, 2021 and 2020, and totaling 9.4 million and 9.0 million for the six months ended June 30, 2021 and 2020, respectively, as they were anti-dilutive.
Risks and Uncertainties	Risks and Uncertainties The Company’s business is subject to risks and uncertainties, including those related to Severe Acute Respiratory Syndrome Coronavirus 2 and the resulting Coronavirus Disease (“COVID-19”) and the risk that we may not get approval of roxadustat in the U.S. for CKD anemia given the fact that the CRDAC voted to recommend not approving roxadustat in July 2021. 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 FDA or other regulatory authorities,
Recently Issued and Adopted Accounting Guidance	Recently Issued and Adopted Accounting Guidance In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes
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 ” , Reference Rate Reform (Topic 848): Scope The Company has certain lease arrangements that are linked to 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 period ended June 30, 2021 and is currently evaluating the impact on its consolidated financial statements and related disclosures upon adoption of this guidance. 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 2020 Form 10-K, except for the following: Product revenue, net Product revenue, net consists of revenues from sales of roxadustat commercial product to Beijing Falikang Pharmaceutical Co., Ltd. (“Falikang”), and directly to pharmaceutical distributors located in a few provinces in China that are not covered by Falikang. Falikang is jointly owned by AstraZeneca AB (“AstraZeneca”) and FibroGen Beijing. The Company is not the primary beneficiary of Falikang for accounting purposes, as AstraZeneca is the final decision maker for all the roxadustat commercialization activities, and the Company lacks the power criterion to direct the activities of Falikang (see Note 3, Variable Interest Entity Sales to Falikang Falikang became fully operational in January 2021, at which time FibroGen Beijing began selling roxadustat commercial product to Falikang. Falikang is FibroGen Beijing’s primary customer in China and substantially all roxadustat product sales to distributors in China are made by Falikang. Falikang bears inventory risk once it receives and accepts the product from FibroGen Beijing, and is responsible for delivering product to its distributors. The promises identified under the AstraZeneca China Agreement (as defined in Note 2, Collaboration Agreements and Revenues Collaboration Agreements and Revenues, The initiation of roxadustat sales to Falikang marked the beginning of the China performance obligation . Revenue is recognized at a point in time when control of roxadustat commercial product is transferred to Falikang. Revenue is recognized based on the estimated transaction price per unit and actual quantity of product delivered during the reporting period. Specifically, the transaction price per unit is determined based on the overall transaction price over the total estimated sales quantity for the estimated performance period in which the Company believes those sales would occur. The price per unit is subject to reassessment on a quarterly basis, which may result in cumulative catch up adjustments due to changes in estimates. The overall transaction price for FibroGen Beijing’s product sales to Falikang includes the following elements of consideration: ● ● ● Interim profit/loss share between FibroGen Beijing and AstraZeneca from April 1, 2020 through December 31, 2020; and ● o o The non-refundable upfront license fees constitute a fixed consideration. The remainder of the above are variable consideration components, which may be constrained, and included in the transaction price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period when the uncertainty associated with the variable consideration is subsequently resolved. The calculation of the above variable consideration includes key estimates such as total sales quantity, performance period, gross transfer price and profit share, which require a substantial degree of judgment. Any net transfer price in excess of the revenue recognized is deferred, and will be recognized over future periods as the performance obligations are satisfied. Direct Sales to Distributors The Company sells roxadustat in China directly to a number of pharmaceutical distributors located in a few provinces in China that are not covered by Falikang. These pharmaceutical distributors are the Company’s customers. Hospitals order roxadustat through a distributor and the Company ships the product directly to the distributors. The delivery of roxadustat to a distributor represents a single performance obligation. Distributors are responsible for delivering product to end users, primarily hospitals. Distributors bear inventory risk once they receive and accept the product. Product revenue is recognized when control of the promised good is transferred to the customer in an amount that reflects the consideration to which the Company expects to be entitled to in exchange for the product. The period between the transfer of control of the promised goods and when the Company receives payment is based on 60-day payment terms. As such, product revenue is not adjusted for the effects of a significant financing component. Product revenue is recorded at the net sales prices which includes the following estimates of variable consideration: ● ● ● Revenue from Contracts with Customers ● Other discounts and rebates, including key account hospital sales reba t e and transfer fee discount, are generally based on a percentage of eligible gross sales made by the distributor and recorded as a reduction to revenue at the point of sale to the distributor; and ● The calculation of the above variable consideration is based on gross sales to the distributor, or estimated utilizing best available information from the distributor, maximum known exposures and other available information including estimated channel inventory levels and estimated sales made by the distributor to hospitals, which involve a substantial degree of judgment. The above rebates and discounts all together are eligible to be applied against the distributor’s future sales order, limited to certain maximums until such rebates and discounts are exhausted. These rebates and discounts are recorded as contract liabilities at the time they become eligible and in the same period that the related revenue is recorded. Due to the distributor’s legal right to offset, at each balance sheet date, the liability for rebates and discounts are presented as reductions of 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 distributor’s legal right of offset is calculated at the individual distributor level. License Acquisition Agreement On June 16, 2021, the Company entered into an exclusive license and option agreement with HiFiBiO Therapeutics (“HiFiBiO”) (“HiFiBiO Agreement”), pursuant to which the Company exclusively licensed all product candidates in HiFiBiO’s Galectin-9 program and will have the sole right to develop them worldwide. The Company has also obtained exclusive options to license all product candidates in HiFiBiO’s CXCR5 and CCR8 programs. Under the terms of the HiFiBiO Agreement, the Company will make a $25 million upfront payment to HiFiBiO, as well as payments upon option exercise. In addition, HiFiBiO may receive up to a total of an additional $1.1 billion in future option, clinical, regulatory, and commercial milestone payments across all three programs. HiFiBiO will also be eligible to receive royalties based upon worldwide net sales. The acquisition of these licenses was accounted for as an asset acquisition. The initial upfront payment of $25.0 million related to the license and options acquisition meets the definition of an in-process research and development asset (“IPR&D asset”) under the ASC 730, Research and Development Contingent consideration payments will be evaluated and recognized when they become probable and reasonably estimable. The related IPR&D asset will only be capitalized if it has an alternative future use other than in a particular research and development project. Otherwise, amounts allocated to IPR&D asset that have no alternative use will be expensed. As of June 30, 2021, all programs were at the early stage of development and the contingencies related to the milestone payments had not been resolved, therefore no contingent consideration was recognized. The Company will reassess the probability of future option payments and contingent payments on a quarterly basis.
Collaboration Arrangements and Revenues	Astellas Agreements Japan Agreement In June 2005, the Company entered into a collaboration agreement with Astellas for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). Under the Japan Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $132.5 million in potential milestone payments, comprised of (i) up to $22.5 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of July 2016), (ii) up to $95.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $15.0 million in milestone payments upon the achievement of specified commercial sales milestone. 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 June 30, 2021 totals $105.1 million, excluding drug product revenue that is discussed separately below. 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”). Under this amendment, FibroGen would continue to manufacture and supply roxadustat active pharmaceutical ingredient (“ API ”) to Astellas for the roxadustat commercial purposes in Japan . The commercial terms of the Japan Agreement relating to the transfer price for roxadustat for commercial use remain substantially the same, reflecting an adjustment for the manufacture of drug product by Astellas rather than FibroGen. The related drug product revenue, as described in details under Drug Product Revenue section below, was $ (2.0) million and $ 2.1 million for the three and six months ended June 30 , 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 paid license fees and other upfront consideration totaling $320.0 million (such amounts were fully received as of February 2009). The Europe Agreement also provides for additional development and regulatory approval milestone payments up to $425.0 million, comprised of (i) up to $90.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of 2012), (ii) up to $335.0 million in milestone payments upon achievement of specified regulatory milestone events. Under 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. The aggregate amount of consideration received under the Europe Agreement through June 30, 2021 totals $540.0 million, excluding drug product revenue that is discussed separately below. 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 Astellas EU Supply Agreement (“EU Supply Agreement”) under the Europe Agreement with Astellas to define general forecast, order, supply and payment terms for Astellas to purchase roxadustat bulk drug product from FibroGen in support of commercial supplies. The Company shipped bulk drug product to Astellas as pre-commercial supply for process validation purposes during the first quarter of 2021. The Company recorded the consideration of $11.8 million from this shipment as deferred revenue as of June 30, 2021, as described in details under Drug Product Revenue 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 paid upfront, non-contingent, non-refundable and time-based payments totaling $374.0 million (such amounts were fully received as of June 2016). Under the U.S./RoW Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $875.0 million in potential milestone payments, comprised of (i) up to $65.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of April 2020), (ii) up to $325.0 million in milestone payments upon achievement of specified regulatory milestone events, (iii) up to $160.0 million in milestone payments related to activity by potential competitors and (iv) up to approximately $325.0 million in milestone payments upon the achievement of specified commercial sales events. The aggregate amount of consideration received under the U.S./RoW Agreement through June 30, 2021 totals $439.0 million, excluding drug product revenue that is discussed separately below. 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. The Company shipped bulk drug product to AstraZeneca as commercial supply during 2020, and the first and second quarter of 2021. On July 15, 2021, the FDA CRDAC voted to recommend not approving roxadustat for the treatment of anemia due to CKD in adult patients. While the FDA is not required to follow the CRDAC’s vote, the agency considers the CRDAC’s non-binding recommendations when making its decision. The Company evaluated the impact of these developments in revising its estimates of variable consideration associated with drug product revenue. As a result, the Company updated the estimated transaction price, and recorded $11.2 million as deferred revenue as of June 30, 2021. See details under Drug Product Revenue 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 totaling $28.2 million (such amounts were fully received in 2014). Under the China Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $348.5 million in potential milestone payments, comprised of (i) up to $15.0 million in milestone payments upon achievement of specified clinical and development milestone events, (ii) up to $146.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $187.5 million in milestone payments upon the achievement of specified commercial sales and other events. 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 the third quarter of 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 June 30, 2021 totals $77.2 million. China Amendment In July 2020, FibroGen China and AstraZeneca (together with FibroGen China, the “Parties”) entered into the China Amendment, effective July 1, 2020, relating to the development and commercialization of roxadustat in China. While the responsibilities of the Parties under the China Agreement remain largely the same, certain changes were made. Under the China Amendment, in September 2020, FibroGen Beijing and AstraZeneca completed the establishment of a jointly owned entity, Falikang, which performs roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. Under the China Amendment, the interim period is defined as the period from April 1, 2020 to the time when Falikang is fully operational. Falikang became fully operational in January 2021. The calculation for profit or loss share related to sales of roxadustat in China has changed for the period from April 1, 2020 onwards. With effect from April 1, 2020, the Parties have changed the method under which commercial expenses incurred by AstraZeneca are calculated and billed. AstraZeneca’s co-promotion expenses for their sales and marketing efforts are now subject to a cap of a percentage of net sales. Once AstraZeneca has been fully reimbursed for their sales and marketing costs under the cap, AstraZeneca will bill the co-promotion expenses based on actual costs on a prospective basis. In addition, the China Amendment has allowed for a higher cost of manufacturing incurred by FibroGen Beijing to be included in the profit or loss share calculation, subject to an annual cap, among other changes. 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 a few provinces 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. In addition, AstraZeneca now bills the co-promotion expenses to Falikang and to FibroGen Beijing, respectively, for its services provided to the respective entity. Development costs continue to be shared 50/50 between the Parties. During the three and six months ended June 30, 2021, the Company recognized $11.8 million and $22.2 million, respectively, of net product revenue from the sales to Falikang, as described in details under Product Revenue, Net In addition to sales to Falikang, during the three and six months ended June 30, 2021, the Company recognized $1.6 million and 6.6 million, respectively, of net product revenue from sales directly to distributors in a few provinces in China, as Product Revenue, Net
Product Revenue, Net	Product Revenue, Net Product revenue, net from the sales of roxadustat commercial product in China was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Direct Sales: Gross revenue $ 2,230 $ 19,833 $ 7,659 $ 25,205 Discounts and rebates (618 ) (4,095 ) (1,181 ) (4,512 ) Sales returns (1 ) (45 ) 88 (45 ) Direct sales revenue, net 1,611 15,693 6,566 20,648 Sales to Falikang: Gross transfer price 26,714 — 51,115 — Profit share (9,573 ) — (19,636 ) — Net transfer price 17,141 — 31,479 Increase in deferred revenue (5,381 ) — (9,312 ) Sales to Falikang revenue, net 11,760 — 22,167 — Total product revenue, net $ 13,371 $ 15,693 $ 28,733 $ 20,648 Direct Sales Product revenue from direct roxadustat product sales to distributors in China is recognized in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those products, net of various sales rebates and discounts. The total discounts and rebates were $0.6 million and $4.1 million for the three months ended June 30, 2021 and 2020, and $1.2 million and $4.5 million for the six months ended June 30, 2021 and 2020, respectively, which primarily consisted of the contractual sales rebate calculated based on the stated percentage of gross sales by each distributor in the distribution agreement entered between FibroGen and each distributor. The rebates and discounts that the Company’s pharmaceutical distributors have earned are eligible to be applied against future sales orders, limited to certain maximums until such rebates and discounts are exhausted. These rebates and discounts are recorded as contract liabilities at the time they become eligible in the same period that the related revenue is recorded. 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 December 31, 2020 Additions Deduction Currency Translation and Other Balance at June 30, 2021 Product revenue - Direct sales - contract liabilities $ (15,137 ) $ (883 ) $ 2,410 $ (183 ) $ (13,793 ) As of June 30, 2021 and December 31, 2020, the total contract liabilities were $13.8 million and $15.1 million, which 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 was $0.8 million and $0.5 million as of June 30, 2021 and December 31, 2020, 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 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 transfer 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 obligations are satisfied . During the three and six months ended June 30, 2021, following updates to its estimates, the Company deferred $5.4 million and $9.3 million, respectively, from the net transfer price to Falikang, which was included in the related deferred revenue of the China performance obligation. The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands): Balance at December 31, 2020 Additions Recognized as Revenue Balance at June 30, 2021 Product revenue - AstraZeneca China performance obligation - deferred revenue $ (137,338 ) $ (34,588 ) $ 22,167 $ (149,759 ) 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 June 30, 2021, approximately $6.3 million of the 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. The reductions to gross accounts receivable related to product revenue to Falikang was $10.1 million as of June 30, 2021.
Drug Product Revenue	Drug Product Revenue Drug product revenue from commercial-grade API or bulk drug product sales to AstraZeneca and Astellas was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Astellas $ (1,974 ) $ 8,238 $ 2,056 $ 8,238 AstraZeneca (6,674 ) — (2,224 ) — Drug product revenue $ (8,648 ) $ 8,238 $ (168 ) $ 8,238 During three months ended June 30, 2021, the Company shipped bulk drug product to AstraZeneca as commercial supply under the terms of the Master Supply Agreement. Based on the above-mentioned FDA CRDAC’s vote on July 15, 2021, the Company evaluated the impact of these developments in revising its estimates of variable consideration associated with drug product revenue. As a result, the Company updated the estimated transaction price, and recorded $11.2 million as deferred revenue as of June 30, 2021. During the three months ended June 30, 2021, the Company recorded a reduction of $2.0 million to the drug product revenue related to the API shipments fulfilled under the terms of the Japan Amendment with Astellas in 2018, due to a change in estimated variable consideration. Specifically, the change in estimated variable consideration was based on the API held by Astellas at June 30, 2021, 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. This amount was recorded under deferred revenue in the condensed consolidated balance sheet as of June 30, 2021. During the first quarter of 2021, the Company recorded $4.0 million drug product revenue related to the same API shipments for the change in estimated variable consideration based on the API held by Astellas at March 31, 2021, under the same methodology. This amount was unbilled to Astellas as of March 31, 2021, and was billed and received from Astellas during the second quarter of 2021. During the three months ended March 31, 2021, the Company shipped bulk drug product from process validation supplies for commercial purposes under the terms of the Europe Agreement and the EU Supply Agreement with Astellas. The Company recorded the consideration of $11.8 million from this shipment as deferred revenue as of June 30, 2021, due to a high degree of uncertainty associated with the final consideration. The deferred revenue will be recognized as and when uncertainty is resolved. The following table includes a roll-forward of the above-mentioned deferred revenues that are considered as contract liabilities related to drug product (in thousands): Balance at December 31, 2020 Additions Recognized as Revenue Balance at June 30, 2021 Astellas - Japan Agreement $ — $ (1,974 ) $ — $ (1,974 ) Astellas - Europe Agreement (5,984 ) (11,759 ) — (17,743 ) AstraZeneca - U.S. Agreement — (11,171 ) — (11,171 ) Drug product revenue - deferred revenue $ (5,984 ) $ (24,904 ) $ — $ (30,888 )

Collaboration Agreements and _2

Collaboration Agreements and Revenues (Tables)	6 Months Ended
	Jun. 30, 2021
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 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Direct Sales: Gross revenue $ 2,230 $ 19,833 $ 7,659 $ 25,205 Discounts and rebates (618 ) (4,095 ) (1,181 ) (4,512 ) Sales returns (1 ) (45 ) 88 (45 ) Direct sales revenue, net 1,611 15,693 6,566 20,648 Sales to Falikang: Gross transfer price 26,714 — 51,115 — Profit share (9,573 ) — (19,636 ) — Net transfer price 17,141 — 31,479 Increase in deferred revenue (5,381 ) — (9,312 ) Sales to Falikang revenue, net 11,760 — 22,167 — Total product revenue, net $ 13,371 $ 15,693 $ 28,733 $ 20,648
Roll-forward of Related Contract Liabilities	The following table includes a roll-forward of the contract liabilities (in thousands): Balance at December 31, 2020 Additions Deduction Currency Translation and Other Balance at June 30, 2021 Product revenue - Direct sales - contract liabilities $ (15,137 ) $ (883 ) $ 2,410 $ (183 ) $ (13,793 )
Schedule of Drug Product Revenue	Drug product revenue from commercial-grade API or bulk drug product sales to AstraZeneca and Astellas was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Astellas $ (1,974 ) $ 8,238 $ 2,056 $ 8,238 AstraZeneca (6,674 ) — (2,224 ) — Drug product revenue $ (8,648 ) $ 8,238 $ (168 ) $ 8,238
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 December 31, 2020 Additions Recognized as Revenue Balance at June 30, 2021 Astellas - Japan Agreement $ — $ (1,974 ) $ — $ (1,974 ) Astellas - Europe Agreement (5,984 ) (11,759 ) — (17,743 ) AstraZeneca - U.S. Agreement — (11,171 ) — (11,171 ) Drug product revenue - deferred revenue $ (5,984 ) $ (24,904 ) $ — $ (30,888 )
AstraZeneca Agreements [Member]
Roll-forward of Related Contract Liabilities	The following table includes a roll-forward of the related deferred revenue that is considered as a contract liability (in thousands): Balance at December 31, 2020 Additions Recognized as Revenue Balance at June 30, 2021 Product revenue - AstraZeneca China performance obligation - deferred revenue $ (137,338 ) $ (34,588 ) $ 22,167 $ (149,759 )
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 (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2021 2020 2021 2020 Japan License revenue $ — $ — $ — $ — Development revenue $ 99 $ 164 $ 179 $ 327
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 Revenue Through June 30, 2021 Deferred Revenue at June 30, 2021 Total Consideration Through June 30, 2021 License $ 100,347 $ — $ 100,347 Development revenue 16,529 30 16,559 Total license and development revenue $ 116,876 $ 30 $ 116,906
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 (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2021 2020 2021 2020 Europe License revenue $ — $ — $ — $ — Development revenue $ 2,546 $ 4,602 $ 6,077 $ 9,176
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 Revenue Through June 30, 2021 Deferred Revenue at June 30, 2021 Total Consideration Through June 30, 2021 License $ 487,951 $ — $ 487,951 Development revenue 255,039 333 255,372 Total license and development revenue $ 742,990 $ 333 $ 743,323
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 and China Agreement with AstraZeneca were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2021 2020 2021 2020 U.S. / RoW and China License revenue $ — $ — $ — $ — Development revenue 16,993 13,750 27,969 28,305 China performance obligation $ — $ 441 $ — $ 594
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 Revenue Through June 30, 2021 Deferred Revenue at June 30, 2021 Total Consideration Through June 30, 2021 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 582,743 2,309 585,052 China performance obligation * 22,167 149,759 171,926 Total license and development revenue $ 946,754 $ 152,068 ** $ 1,098,822 * China performance obligation revenue is recognized as product revenue, as described in details under Product Revenue, Net ** Contract assets and liabilities related to rights and obligations in the same contract are recorded net on the consolidated balance sheets. As of June 30, 2021, deferred revenue included $146.8 million related to the U.S./RoW and China Agreement, which represents the net of $152.1 million of deferred revenue presented above and a $5.3 million unbilled co-development revenue under the China Amendment with AstraZeneca.

Variable Interest Entity (Table

Variable Interest Entity (Tables)	6 Months Ended
	Jun. 30, 2021
Acquisition And Variable Interest Entity [Abstract]
Summary of Equity Method Investment	The Company’s equity method investment in Falikang was as follows (in thousands): Entity Ownership Percentage Balance at December 31, 2020 Share of Net Income Currency Translation Balance at June 30, 2021 Falikang 51.1 % $ 2,728 $ 323 $ 32 $ 3,083

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Values of Financial Assets Measured on Recurring Basis	The fair values of the Company’s financial assets that are measured on a recurring basis are as follows (in thousands): June 30, 2021 Level 1 Level 2 Level 3 Total Money market funds $ 220,627 $ — $ — $ 220,627 Corporate bonds — 104,483 — 104,483 Commercial paper — 72,099 — 72,099 U.S. government bonds 46,568 — — 46,568 Agency bonds — 14,284 — 14,284 Asset-backed securities — 12,490 — 12,490 Foreign government bonds — 12,151 — 12,151 Equity investments 233 — — 233 Total $ 267,428 $ 215,507 $ — $ 482,935 December 31, 2020 Level 1 Level 2 Level 3 Total Bond and mutual funds $ — $ 8,144 $ — $ 8,144 Equity investments 244 — — 244 Money market funds 590,347 — — 590,347 Total $ 590,591 $ 8,144 $ — $ 598,735

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Schedule of Lease Assets and Related Lease Liabilities	The Company’s lease assets and related lease liabilities were as follows (in thousands): Balance Sheet Line Item June 30, 2021 December 31, 2020 Assets Finance: Right-of-use assets - cost $ 2,007 $ 50,477 Accumulated amortization (1,146 ) (20,871 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 861 29,606 Operating: Right-of-use assets - cost 100,705 3,934 Accumulated amortization (3,614 ) (1,891 ) Operating lease right-of-use assets, net Operating lease right-of-use assets 97,091 2,043 Total lease assets $ 97,952 $ 31,649 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 23 $ 12,330 Operating lease liabilities Operating lease liabilities, current 10,718 1,188 Non-current: Finance lease liabilities Finance lease liabilities, non-current 6 25,391 Operating lease liabilities Operating lease liabilities, non-current 94,196 853 Total lease liabilities $ 104,943 $ 39,762
Components of Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Statement of Operations Line Item 2021 2020 2021 2020 Finance lease cost: Amortization of right-of-use assets Cost of goods sold; Research and development; Selling, general and administrative expenses $ 1,777 $ 2,653 $ 4,393 $ 5,247 Interest on lease liabilities Interest expense 242 534 627 1,049 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 1,744 255 2,162 564 Sublease income Selling, general and administrative expenses (275 ) (306 ) (575 ) (598 ) Total lease cost $ 3,488 $ 3,136 $ 6,607 $ 6,262
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases were as follows (in thousands): Six Months Ended June 30, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,246 $ 433 Operating cash flows from finance leases 628 1,010 Financing cash flows from finance leases 5,326 5,992 Non-cash: Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 303 144 Operating leases 3,498 5 Non-cash: Increase (decrease) resulting from lease modification: Finance lease right-of-use assets (24,654 ) — Operating lease right-of-use assets 93,222 — Finance lease liabilities, current (12,587 ) — Operating lease liabilities, current 9,221 — Finance lease liabilities, non-current (20,009 ) — Operating lease liabilities, non-current $ 91,943 $ —
Schedule of Lease Term and Discount Rate	Lease term and discount rate were as follows: June 30, 2021 December 31, 2020 Weighted-average remaining lease term (years): Finance leases 1.3 2.9 Operating leases 7.3 1.8 Weighted-average discount rate: Finance leases 4.55 % 4.39 % Operating leases 4.75 % 4.74 %
Schedule of Maturities of Finance and Operating Leases Liabilities	Maturities of lease liabilities as of June 30, 2021 are as follows (in thousands): Year Ending December 31, Finance Leases Operating Leases 2021 (remaining six month period) $ 16 $ 7,534 2022 11 15,517 2023 3 13,454 2024 — 16,798 2025 — 18,193 Beyond 2025 — 53,881 Total future lease payments 30 125,377 Less: Interest (1 ) (20,463 ) Present value of lease liabilities $ 29 $ 104,914

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): June 30, 2021 December 31, 2020 Cash $ 130,035 $ 88,046 Commercial paper 2,699 — Money market funds 220,627 590,347 Total cash and cash equivalents $ 353,361 $ 678,393
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): June 30, 2021 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 104,499 $ 27 $ (43 ) $ 104,483 Commercial paper 69,400 — — 69,400 U.S. government bonds 46,589 — (21 ) 46,568 Agency bonds 14,288 2 (6 ) 14,284 Asset-backed securities 12,489 1 — 12,490 Foreign government bonds 12,151 1 (1 ) 12,151 Equity investments 118 115 — 233 Total investments $ 259,534 $ 146 $ (71 ) $ 259,609 December 31, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Bond and mutual funds $ 8,147 $ — $ (3 ) $ 8,144 Equity investments 125 119 — 244 Total investments $ 8,272 $ 119 $ (3 ) $ 8,388
Schedule of Inventory	Inventories consisted of the following (in thousands): June 30, 2021 December 31, 2020 Raw materials $ 1,190 $ 2,303 Work-in-progress 15,541 8,114 Finished goods 7,799 6,113 Total inventories $ 24,530 $ 16,530
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2021 December 31, 2020 Unbilled contract assets $ 5,256 $ 2,147 Deferred revenues from associated contracts (5,256 ) (2,147 ) Net unbilled contract assets — — Prepaid assets 7,149 8,353 Other current assets 1,309 1,807 Total prepaid expenses and other current assets $ 8,458 $ 10,160
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): June 30, 2021 December 31, 2020 Leasehold improvements $ 102,657 $ 102,006 Laboratory equipment 19,247 18,143 Machinery 8,387 8,312 Computer equipment 9,205 9,545 Furniture and fixtures 6,126 6,128 Construction in progress 1,407 760 Total property and equipment $ 147,029 $ 144,894 Less: accumulated depreciation (116,359 ) (111,247 ) Property and equipment, net $ 30,670 $ 33,647
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): June 30, 2021 December 31, 2020 Preclinical and clinical trial accruals $ 65,274 $ 44,113 Payroll and related accruals 18,047 22,800 Contract liabilities to pharmaceutical distributors 13,793 15,137 Accrued co-promotion expenses - current 20,832 11,537 Roxadustat profit share to AstraZeneca 7,007 7,007 Property taxes and other taxes 10,344 5,970 Professional services 7,471 4,869 Other 5,033 6,900 Total accrued and other current liabilities $ 147,801 $ 118,333
Schedule of Other Long-term Liabilities	Other long-term liabilities consisted of the following (in thousands): June 30, 2021 December 31, 2020 Accrued long-term co-promotion expenses $ 19,205 $ 27,424 Other long-term tax liabilities 8,985 8,675 Other 2,469 2,690 Total other long-term liabilities $ 30,659 $ 38,789

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Recorded Stock-Based Compensation Expense	Stock-based compensation expense was recorded directly to research and development and selling, general and administrative expense as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Research and development $ 10,681 $ 10,780 $ 22,903 $ 21,417 Selling, general and administrative 8,320 6,864 15,482 13,143 Total stock-based compensation expense $ 19,001 $ 17,644 $ 38,385 $ 34,560
Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Purchases under 2014 Employee Share Purchase Plan	The assumptions used to estimate the fair value of stock options granted and purchases under the Company’s 2014 Employee Share Purchase Plan (“ESPP”) using the Black-Scholes option valuation model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Stock Options Expected term (in years) 5.6 5.5 5.7 5.7 Expected volatility 63.4 % 69.2 % 59.4 % 68.4 % Risk-free interest rate 0.9 % 0.4 % 0.7 % 0.8 % Expected dividend yield — — — — Weighted average estimated fair value $ 11.91 $ 21.72 $ 25.38 $ 17.75 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Expected volatility 47.5 - 104.2 % 49.5 - 77.1 % 47.5 - 104.2 % 49.5 - 77.1 % Risk-free interest rate 0.0 - 2.2 % 0.2 - 2.9 % 0.0 - 2.2 % 0.2 - 2.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 13.60 $ 17.82 $ 14.69 $ 18.11

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail) shares in Millions	Jun. 16, 2021USD ($)	Jun. 30, 2021shares	Jun. 30, 2020shares	Jun. 30, 2021Segmentshares	Jun. 30, 2020shares
Accounting Policy [Line Items]
Number of operating segment | Segment				1
Anti-dilutive shares outstanding | shares		11.4	9.2	9.4	9
Description of payment term				The period between the transfer of control of the promised goods and when the Company receives payment is based on 60-day payment terms.
Description of sales return				Distributors can request to return product to the Company only due to quality issues or for product purchased within one year prior to the product’s expiration date.
AstraZeneca Agreements [Member]
Accounting Policy [Line Items]
Profit share percent				50.00%
HiFiBiO Agreement [Member]
Accounting Policy [Line Items]
Initial upfront payment	$ 25,000,000
Maximum additional future option, clinical, regulatory, and commercial milestone payments	1,100,000,000
Contingent consideration	$ 0

Collaboration Agreements and _3

Collaboration Agreements and Revenues - Astellas Agreements - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		35 Months Ended	45 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Feb. 28, 2009	Feb. 28, 2009	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 24,364	$ 42,888	$ 62,793	$ 67,288
Deferred Revenue			25,234		25,234				$ 6,547
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			(8,648)	$ 8,238	(168)	$ 8,238
Deferred Revenue			11,200		$ 11,200
Astellas Agreement [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received								$ 40,100
Potential milestone payments		$ 132,500
Commercial sales milestone		15,000
Additional consideration based on net sales description					the low 20% range of the list price
Aggregate consideration received excluding drug product revenue			105,100		$ 105,100
Astellas Agreement [Member] | Japan [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		22,500
Astellas Agreement [Member] | Japan [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		$ 95,000
Astellas Agreement [Member] | Japan [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			(2,000)		$ 2,100
Astellas Agreement [Member] | Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received							$ 320,000
Additional consideration based on net sales description					low 20% range
Aggregate consideration received excluding drug product revenue			540,000		$ 540,000
Development and regulatory approval milestones	$ 425,000
Percentage of joint development costs committed to fund	50.00%
Astellas Agreement [Member] | Europe [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 90,000
Astellas Agreement [Member] | Europe [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 335,000
Astellas Agreement [Member] | Europe [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue			$ 11,800		$ 11,800

Collaboration Agreements and _4

Collaboration Agreements and Revenues - AstraZeneca Agreements - Additional Information 1 (Detail) - USD ($) $ in Thousands	Jul. 30, 2013	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue		$ 25,234		$ 25,234		$ 6,547
Revenue recognized		24,364	$ 42,888	62,793	$ 67,288
Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized		13,371	15,693	28,733	20,648
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue		11,200		11,200
Revenue recognized		(8,648)	8,238	(168)	8,238
AstraZeneca Agreements [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue		11,200		11,200
Revenue recognized		(6,674)	0	(2,224)	0
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	$ 374,000
Potential milestone payments	875,000
Commercial sales milestone	325,000
Aggregate consideration received excluding drug product revenue		439,000		439,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	65,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	325,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Deferred Approval Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	160,000
AstraZeneca Agreements [Member] | China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	348,500
Deferred Revenue		7,000		7,000		$ 7,000
Proceeds from upfront, non-contingent and non-refundable payments	28,200
Commercial sales and other events milestone	187,500
Aggregate consideration received for milestone and upfront payments		77,200		77,200
Revenue recognized		0	441	0	594
AstraZeneca Agreements [Member] | China [Member] | Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized		11,800		22,200
AstraZeneca Agreements [Member] | China [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	15,000
AstraZeneca Agreements [Member] | China [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 146,000
Direct Sales [Member] | Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized		1,611	$ 15,693	6,566	$ 20,648
Direct Sales [Member] | China [Member] | Product Revenue, Net [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized		$ 1,600		$ 6,600

Collaboration Agreements and _5

Collaboration Agreements and Revenues - Summary of License Revenue and Development Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 24,364	$ 42,888	$ 62,793	$ 67,288
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	0
Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	19,641	18,957	34,228	38,402
Astellas Agreement [Member] | License Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	0
Astellas Agreement [Member] | License Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	0
Astellas Agreement [Member] | Development Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	99	164	179	327
Astellas Agreement [Member] | Development Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	2,546	4,602	6,077	9,176
AstraZeneca Agreements [Member] | China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	441	0	594
AstraZeneca Agreements [Member] | License Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	0
AstraZeneca Agreements [Member] | Development Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 16,993	$ 13,750	$ 27,969	$ 28,305

Collaboration Agreements and _6

Collaboration Agreements and Revenues - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	$ 5,256	$ 2,147
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	116,876
Deferred Revenue	30
Total Consideration	116,906
Astellas Agreement [Member] | Japan [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	16,529
Deferred Revenue	30
Total Consideration	16,559
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	742,990
Deferred Revenue	333
Total Consideration	743,323
Astellas Agreement [Member] | Europe [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	255,039
Deferred Revenue	333
Total Consideration	255,372
Astellas Agreement [Member] | Europe [Member] | License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	487,951
Deferred Revenue	0
Total Consideration	487,951
AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	149,759	$ 137,338
AstraZeneca Agreements [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	946,754
Deferred Revenue	152,068
Total Consideration	1,098,822
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	582,743
Deferred Revenue	2,309
Total Consideration	585,052
AstraZeneca Agreements [Member] | U.S./RoW and China [Member] | China performance obligation [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	22,167
Deferred Revenue	149,759
Total Consideration	$ 171,926

Collaboration Agreements and _7

Collaboration Agreements and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail) $ in Millions	3 Months Ended
	Jun. 30, 2021USD ($)
Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Remainder of transaction price, variable consideration from estimated future co-development billing	$ 10.7
Europe [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue from changes to estimated variable consideration	0.4
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	34.1
U.S./RoW and China [Member] | AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue from changes to estimated variable consideration	$ 0.2

Collaboration Agreements and _8

Collaboration Agreements and Revenues - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue (Parenthetical) (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue, net of current ($9,381 and $4,636 to a related party)	$ 152,865	$ 138,474
Deferred Revenue	5,256	2,147
Net unbilled co-development revenue	0	0
AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	149,759	$ 137,338
Net unbilled co-development revenue	5,300
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue, net of current ($9,381 and $4,636 to a related party)	146,800
Deferred Revenue	152,100
Net unbilled co-development revenue	$ 5,300

Collaboration Agreements and _9

Collaboration Agreements and Revenues - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Total revenue	$ 24,364	$ 42,888	$ 62,793	$ 67,288
Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	600	4,100	1,200	4,500
Product Revenue, Net [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	13,371	15,693	28,733	20,648
Product Revenue, Net [Member] | Direct Sales [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	2,230	19,833	7,659	25,205
Total revenue	1,611	15,693	6,566	20,648
Product Revenue, Net [Member] | Direct Sales [Member] | Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(618)	(4,095)	(1,181)	(4,512)
Product Revenue, Net [Member] | Direct Sales [Member] | Sales Returns [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(1)	(45)	88	(45)
Product Revenue, Net [Member] | Sales To Falikang [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	11,760	0	22,167	0
Gross transfer price	26,714	0	51,115	0
Product Revenue, Net [Member] | Sales To Falikang [Member] | Profit Share [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(9,573)	0	(19,636)	0
Product Revenue, Net [Member] | Sales To Falikang [Member] | Net Transfer Price [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	17,141	0	31,479	0
Product Revenue, Net [Member] | Sales To Falikang [Member] | Increase in Deferred Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ (5,381)	$ 0	$ (9,312)	$ 0

Collaboration Agreements and_10

Collaboration Agreements and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 24,364	$ 42,888	$ 62,793	$ 67,288
Discounts and Rebates [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	600	$ 4,100	1,200	$ 4,500
Rebates and Discounts [Member] | Gross Accounts Receivable [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			800		$ 500
Rebates and Discounts [Member] | Contract Liabilities [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			13,800		$ 15,100
Constrained for Future Recognition [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 5,400		$ 9,300

Collaboration Agreements and_11

Collaboration Agreements and Revenues - Roll-forward of Related Contract Liabilities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	$ (2,147)
Balance at June 30, 2021	(5,256)
AstraZeneca Agreements [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	(137,338)
Additions	(34,588)
Recognized as Revenue	22,167
Balance at June 30, 2021	(149,759)
Product Revenue, Net [Member] | Direct Sales [Member] | Contract Liabilities [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	(15,137)
Additions	(883)
Deduction	2,410
Currency Translation and Other	(183)
Balance at June 30, 2021	(13,793)
Drug Product Revenue [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	(5,984)
Additions	(24,904)
Recognized as Revenue	0
Balance at June 30, 2021	(30,888)
Drug Product Revenue [Member] | AstraZeneca Agreements [Member] | U.S. [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	0
Additions	(11,171)
Recognized as Revenue	0
Balance at June 30, 2021	(11,171)
Drug Product Revenue [Member] | Astellas Agreement [Member] | Japan [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	0
Additions	(1,974)
Recognized as Revenue	0
Balance at June 30, 2021	(1,974)
Drug Product Revenue [Member] | Astellas Agreement [Member] | Europe [Member]
Contract with Customer Liability [Line Items]
Balance at December 31, 2020	(5,984)
Additions	(11,759)
Recognized as Revenue	0
Balance at June 30, 2021	$ (17,743)

Collaboration Agreements and_12

Collaboration Agreements and Revenues - Deferred Revenue - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue	$ 5,256	$ 2,147
Product Revenue, Net [Member] | Beijing Falikang Pharmaceutical Co Ltd
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reductions to gross accounts receivable	10,100
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue	149,759	$ 137,338
AstraZeneca Agreements [Member] | China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue	$ 6,300

Collaboration Agreements and_13

Collaboration Agreements and Revenues - Drug Product Revenue - Summary of Drug Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	$ 24,364	$ 42,888	$ 62,793	$ 67,288
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	(8,648)	8,238	(168)	8,238
Drug Product Revenue [Member] | Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	(1,974)	8,238	2,056	8,238
Drug Product Revenue [Member] | AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	$ (6,674)	$ 0	$ (2,224)	$ 0

Collaboration Agreements and_14

Collaboration Agreements and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	$ 25,234			$ 25,234		$ 6,547
Drug product revenue recognized	24,364		$ 42,888	62,793	$ 67,288
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	11,200			11,200
Drug product revenue recognized	(8,648)		8,238	(168)	8,238
Drug Product Revenue [Member] | Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	(1,974)		$ 8,238	2,056	$ 8,238
Drug Product Revenue [Member] | Europe [Member] | Astellas Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue	11,800			$ 11,800
Drug Product Revenue [Member] | API Shipment [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 2,000	$ 4,000

Variable Interest Entity - Addi

Variable Interest Entity - Additional Information (Detail)	Jun. 30, 2021
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) - Beijing Falikang Pharmaceutical Co. Ltd [Member] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021
Acquisition And Variable Interest Entity [Line Items]
Ownership Percentage	51.10%
Beginning balance	$ 2,728
Share of Net Income	323
Currency Translation	32
Ending balance	$ 3,083

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 259,609	$ 8,388
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	104,483
Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	69,400
Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,490
Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,151
Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		8,144
Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	233	244
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	482,935	598,735
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	220,627	590,347
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	104,483
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	72,099
Fair Value, Measurements, Recurring [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	46,568
Fair Value, Measurements, Recurring [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	14,284
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,490
Fair Value, Measurements, Recurring [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	12,151
Fair Value, Measurements, Recurring [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	8,144
Fair Value, Measurements, Recurring [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	233	244
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	267,428	590,591
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	220,627	590,347
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
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	46,568
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Bond and mutual funds [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] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	233	244
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	215,507	8,144
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	104,483
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	72,099
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
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	14,284
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	12,490
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	12,151
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	8,144
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Equity investments [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]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Bond and mutual funds [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] | Equity investments [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) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Transfers of assets from level 1 to 2	$ 0	$ 0
Transfers of assets from level 2 to 1	0	0
Transfers of assets into level 3	0	0
Transfers of assets out of level 3	0	0
Liabilities fair value disclosure	900,000	1,100,000
Transfers of liabilities from level 1 to 2	0	0
Transfers of liabilities from level 2 to 1	0	0
Transfers of liabilities into level 3	0	0
Transfers of liabilities out of level 3	$ 0	$ 0

Leases - Schedule of Lease Asse

Leases - Schedule of Lease Assets and Related Lease Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Right-of-use assets - cost	$ 2,007	$ 50,477
Accumulated amortization	(1,146)	(20,871)
Finance lease right-of-use assets, net	861	29,606
Right-of-use assets - cost	100,705	3,934
Accumulated amortization	(3,614)	(1,891)
Operating lease right-of-use assets, net	97,091	2,043
Total lease assets	97,952	31,649
Finance lease liabilities	23	12,330
Operating lease liabilities	10,718	1,188
Finance lease liabilities	6	25,391
Operating lease liabilities	94,196	853
Total lease liabilities	$ 104,943	$ 39,762

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	Jun. 01, 2021USD ($)Option	Mar. 31, 2021USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Lessee Lease Description [Line Items]
Finance lease right-of-use assets			$ 861		$ 29,606
Finance lease liability			29
Operating lease right-of-use assets			97,091		$ 2,043
Operating lease liability			104,914
Cash payment related to lease			2,246	$ 433
ASC 842 [Member]
Lessee Lease Description [Line Items]
Finance lease right-of-use assets			24,654	0
Operating lease right-of-use assets			$ 93,222	$ 0
Shorenstein Properties LLC [Member]
Lessee Lease Description [Line Items]
Lessee, finance lease, initial lease term			15 years
Lessee, finance lease, expiration period			2023
Shorenstein Properties LLC [Member] | Lease Amendment [Member]
Lessee Lease Description [Line Items]
Lessee, finance lease, existence of option to extend	true
Lessee, finance lease, additional lease expiration period	2028
Percentage increases on each anniversary of rent commencement date 2023	2.00%
Lessee, finance lease, option to extend	Under the terms of the Lease Amendment, the Company has two optional rights to each extend the lease for an additional five years.
Optional rights to extend lease | Option	2
Lessee, finance lease, option to extend the additional lease term	5 years
Rent increase commencement year first option	2023
Percentage increases on each anniversary of rent commencement date 2028	3.00%
Rent increase commencement year second option	2028
Shorenstein Properties LLC [Member] | Lease Amendment [Member] | ASC 842 [Member]
Lessee Lease Description [Line Items]
Finance lease right-of-use assets	$ 24,600
Finance lease liability	32,600
Operating lease right-of-use assets	93,200
Operating lease liability	$ 101,200
Cash payment related to lease			$ 1,100
Beijing Economic-Technological Development Area [Member]
Lessee Lease Description [Line Items]
Operating lease right-of-use assets		$ 3,400
Operating lease liability		$ 3,400
Lessee, operating lease, lease term		5 years
Lessee, operating lease, expiration period		2026

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Finance lease cost:
Amortization of right-of-use assets	$ 1,777	$ 2,653	$ 4,393	$ 5,247
Interest on lease liabilities	242	534	627	1,049
Operating lease cost	1,744	255	2,162	564
Sublease income	(275)	(306)	(575)	(598)
Total lease cost	$ 3,488	$ 3,136	$ 6,607	$ 6,262

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 2,246	$ 433
Operating cash flows from finance leases	628	1,010
Financing cash flows from finance leases	5,326	5,992
Non-cash: Right-of-use assets obtained in exchange for new lease liabilities:
Finance leases	303	144
Operating leases	3,498	5
Non-cash: Increase (decrease) resulting from lease modification:
Finance lease right-of-use assets	(861)		$ (29,606)
Operating lease right-of-use assets	97,091		2,043
Finance lease liabilities, current	(23)		(12,330)
Operating lease liabilities, current	10,718		1,188
Finance lease liabilities, non-current	(6)		(25,391)
Operating lease liabilities, non-current	94,196		$ 853
ASC 842 [Member]
Non-cash: Increase (decrease) resulting from lease modification:
Finance lease right-of-use assets	(24,654)	0
Operating lease right-of-use assets	93,222	0
Finance lease liabilities, current	(12,587)	0
Operating lease liabilities, current	9,221	0
Finance lease liabilities, non-current	(20,009)	0
Operating lease liabilities, non-current	$ 91,943	$ 0

Leases - Schedule of Lease Term

Leases - Schedule of Lease Term and Discount Rate (Detail)	Jun. 30, 2021	Dec. 31, 2020
Weighted-average remaining lease term (years):
Finance leases	1 year 3 months 18 days	2 years 10 months 24 days
Operating leases	7 years 3 months 18 days	1 year 9 months 18 days
Weighted-average discount rate:
Finance leases	4.55%	4.39%
Operating leases	4.75%	4.74%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Detail) $ in Thousands	Jun. 30, 2021USD ($)
Finance Leases
2021 (remaining six month period)	$ 16
2022	11
2023	3
2024	0
2025	0
Beyond 2025	0
Total future lease payments	30
Less: Interest	(1)
Present value of lease liabilities	29
Operating Leases
2021 (remaining six month period)	7,534
2022	15,517
2023	13,454
2024	16,798
2025	18,193
Beyond 2025	53,881
Total future lease payments	125,377
Less: Interest	(20,463)
Present value of lease liabilities	$ 104,914

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Cash And Cash Equivalents [Abstract]
Cash	$ 130,035	$ 88,046
Commercial paper	2,699	0
Money market funds	220,627	590,347
Total cash and cash equivalents	$ 353,361	$ 678,393

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 353,361,000	$ 353,361,000	$ 678,393,000
Other-than-temporary impairment loss	$ 0	$ 0
Percentage of pre-launch inventory capitalized of aggregate inventory balance	37.00%	37.00%	29.00%
Net unbilled co-development revenue	$ 0	$ 0	$ 0
Profit share liability	25,234,000	25,234,000	6,547,000
AstraZeneca Agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Net unbilled co-development revenue	5,300,000	5,300,000
AstraZeneca Agreements [Member] | China [Member]
Schedule of Available-for-sale Securities [Line Items]
Profit share liability	7,000,000	$ 7,000,000	7,000,000
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	$ 85,100,000	$ 85,100,000	$ 66,000,000

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	Jun. 30, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 259,534	$ 8,272
Gross Unrealized Holding Gains	146	119
Gross Unrealized Holding Losses	(71)	(3)
Fair Value	259,609	8,388
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	104,499
Gross Unrealized Holding Gains	27
Gross Unrealized Holding Losses	(43)
Fair Value	104,483
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	69,400
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Fair Value	69,400
U.S. government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	46,589
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	(21)
Fair Value	46,568
Agency bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,288
Gross Unrealized Holding Gains	2
Gross Unrealized Holding Losses	(6)
Fair Value	14,284
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,489
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	0
Fair Value	12,490
Foreign government bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,151
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	(1)
Fair Value	12,151
Bond and mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		8,147
Gross Unrealized Holding Gains		0
Gross Unrealized Holding Losses		(3)
Fair Value		8,144
Equity investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	118	125
Gross Unrealized Holding Gains	115	119
Gross Unrealized Holding Losses	0	0
Fair Value	$ 233	$ 244

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Investments [Abstract]
Raw materials	$ 1,190	$ 2,303
Work-in-progress	15,541	8,114
Finished goods	7,799	6,113
Total inventories	$ 24,530	$ 16,530

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Unbilled contract assets	$ 5,256	$ 2,147
Deferred revenues from associated contracts	(5,256)	(2,147)
Net unbilled contract assets	0	0
Prepaid assets	7,149	8,353
Other current assets	1,309	1,807
Total prepaid expenses and other current assets	$ 8,458	$ 10,160

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 147,029	$ 144,894
Less: accumulated depreciation	(116,359)	(111,247)
Property and equipment, net	30,670	33,647
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	102,657	102,006
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	19,247	18,143
Machinery [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,387	8,312
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	9,205	9,545
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,126	6,128
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,407	$ 760

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 65,274	$ 44,113
Payroll and related accruals	18,047	22,800
Contract liabilities to pharmaceutical distributors	13,793	15,137
Accrued co-promotion expenses - current	20,832	11,537
Roxadustat profit share to AstraZeneca	7,007	7,007
Property taxes and other taxes	10,344	5,970
Professional services	7,471	4,869
Other	5,033	6,900
Total accrued and other current liabilities	$ 147,801	$ 118,333

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Other Liabilities Noncurrent [Abstract]
Accrued long-term co-promotion expenses	$ 19,205	$ 27,424
Other long-term tax liabilities	8,985	8,675
Other	2,469	2,690
Total other long-term liabilities	$ 30,659	$ 38,789

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Recorded Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 19,001	$ 17,644	$ 38,385	$ 34,560
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	10,681	10,780	22,903	21,417
Selling, general and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 8,320	$ 6,864	$ 15,482	$ 13,143

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Purchases under 2014 Employee Share Purchase Plan (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 7 months 6 days	5 years 6 months	5 years 8 months 12 days	5 years 8 months 12 days
Expected volatility	63.40%	69.20%	59.40%	68.40%
Risk-free interest rate	0.90%	0.40%	0.70%	0.80%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 11.91	$ 21.72	$ 25.38	$ 17.75
2014 Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	47.50%	49.50%	47.50%	49.50%
Expected volatility, maximum	104.20%	77.10%	104.20%	77.10%
Risk-free interest rate, minimum	0.00%	0.20%	0.00%	0.20%
Risk-free interest rate, maximum	2.20%	2.90%	2.20%	2.90%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 13.60	$ 17.82	$ 14.69	$ 18.11
2014 Employee Share Purchase Plan [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months	6 months
2014 Employee Share Purchase Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	2 years	2 years	2 years	2 years

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related Party Transaction [Line Items]
Accounts receivable from related party	$ 13,352,000		$ 13,352,000		$ 4,127,000
Accrued liabilities to related party	14,000		14,000		24,000
Deferred revenue	5,256,000		5,256,000		2,147,000
Astellas [Member]
Related Party Transaction [Line Items]
Drug product revenue from a related party	(2,000,000)	$ 8,200,000	2,100,000	$ 8,200,000
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	2,600,000	$ 4,800,000	6,300,000	$ 9,500,000
Accounts receivable from related party	2,600,000		2,600,000		4,100,000
Accrued liabilities to related party					1,100,000
Deferred revenue	20,100,000		20,100,000		7,500,000
Falikang [Member]
Related Party Transaction [Line Items]
Accounts receivable from related party	10,800,000		10,800,000
Investment income	600,000		300,000
Equity method investments	3,100,000		$ 3,100,000		2,700,000
Percentage of outstanding shares owned			51.10%
Miscellaneous receivables	0		$ 0		$ 900,000
Falikang [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	$ 11,800,000		$ 22,200,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	1 Months Ended		6 Months Ended
	May 31, 2021PutativeClassAction	Apr. 30, 2021PutativeClassAction	Jun. 30, 2021USD ($)
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations			$ 81.9
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			29.6
Manufacture and Supply of Pamrevlumab [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations			47.3
Other Purchases [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable purchase obligations			5
Research and Pre-Clinical Stage Development Programs [Member]
Commitments And Contingencies [Line Items]
Maximum future milestone payments			$ 359.2

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 19, 2021	Jun. 30, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Deferred Revenue		$ 25,234	$ 6,547
Subsequent Event [Member] | Eluminex [Member]
Subsequent Event [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
Drug Product Revenue [Member]
Subsequent Event [Line Items]
Deferred Revenue		$ 11,200