FibroGen (FGEN) 10-Q 5 Nov 20 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	FGEN
Entity Registrant Name	FIBROGEN, INC.
Entity Central Index Key	0000921299
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity File Number	1-36740
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		91,010,718

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 532,468	$ 126,266
Short-term investments	155,398	407,491
Accounts receivable, net ($4,715 and $4,845 from a related party)	26,252	28,455
Inventories	11,803	6,887
Prepaid expenses and other current assets ($165 and $125,210 from related parties)	11,563	133,391
Total current assets	737,484	702,490
Restricted time deposits	2,072	2,072
Long-term investments	247	61,118
Property and equipment, net	36,153	42,743
Finance lease right-of-use assets	32,028	39,602
Other assets ($1,483 and $0 from a related party)	4,031	9,372
Total assets	812,015	857,397
Current liabilities:
Accounts payable	7,553	6,088
Accrued and other current liabilities ($4,135 and $36,883 to a related party)	90,572	83,816
Deferred revenue	7,912	490
Finance lease liabilities, current	12,311	12,351
Total current liabilities	118,348	102,745
Long-term portion of lease obligations	839	1,141
Product development obligations	17,790	16,780
Deferred revenue, net of current	137,954	99,449
Finance lease liabilities, non-current	28,514	37,610
Other long-term liabilities	37,639	64,266
Total liabilities	341,084	321,991
Commitments and Contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at September 30, 2020 and December 31, 2019	0	0
Common stock, $0.01 par value; 225,000 shares authorized at September 30, 2020 and December 31, 2019; 90,885 and 87,657 shares issued and outstanding at September 30, 2020 and December 31, 2019	909	877
Additional paid-in capital	1,370,384	1,300,725
Accumulated other comprehensive loss	(4,256)	(747)
Accumulated deficit	(915,377)	(784,720)
Total stockholders’ equity	451,660	516,135
Non-controlling interests	19,271	19,271
Total equity	470,931	535,406
Total liabilities, stockholders’ equity and non-controlling interests	$ 812,015	$ 857,397

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Accounts receivable from related party	$ 4,715	$ 4,845
Prepaid expenses and other current assets from related parties	165	125,210
Other assets from related party	1,483	0
Accrued and other current liabilities to related party	$ 4,135	$ 36,883
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	90,885,000	87,657,000
Common stock, shares outstanding	90,885,000	87,657,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue:
Total revenue	$ 44,032	$ 33,174	$ 111,320	$ 248,603
Operating costs and expenses:
Cost of goods sold	$ 2,207	$ 242	$ 6,253	$ 242
Cost, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Research and development	$ 58,476	$ 49,963	$ 174,792	$ 152,467
Selling, general and administrative	(48,981)	35,823	64,157	84,772
Total operating costs and expenses	11,702	86,028	245,202	237,481
Income (loss) from operations	32,330	(52,854)	(133,882)	11,122
Interest and other, net
Interest expense	(580)	(702)	(1,864)	(2,209)
Interest income and other, net (includes $(13), $0, $(13) and $0 from a related party)	1,469	4,193	5,279	12,496
Total interest and other, net	889	3,491	3,415	10,287
Income (loss) before income taxes	33,219	(49,363)	(130,467)	21,409
Provision for income taxes	215	76	190	256
Net income (loss)	$ 33,004	$ (49,439)	$ (130,657)	$ 21,153
Net income (loss) per share:
Basic	$ 0.36	$ (0.57)	$ (1.46)	$ 0.24
Diluted	$ 0.35	$ (0.57)	$ (1.46)	$ 0.23
Weighted average number of common shares used to calculate net income (loss) per share:
Basic	90,558	87,007	89,414	86,390
Diluted	93,678	87,007	89,414	91,995
License Revenue [Member]
Revenue:
Total revenue	$ 0	$ 11,935	$ 0	$ 162,517
Development and Other Revenue [Member]
Revenue:
Total revenue	20,663	20,660	59,065	85,507
Product Revenue, Net [Member]
Revenue:
Total revenue	22,683	579	43,331	579
Drug Product Revenue [Member]
Revenue:
Total revenue	$ 686	$ 0	$ 8,924	$ 0

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - Astellas Agreement [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
License and milestone revenue from a related party	$ 0	$ 11,935	$ 0	$ 129,405
Collaboration services and other revenue from a related party	4,736	3,533	14,239	25,615
Drug product revenue from a related party	(3,957)	0	4,281	0
Interest income and other net from related party	$ (13)	$ 0	$ (13)	$ 0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 33,004	$ (49,439)	$ (130,657)	$ 21,153
Other comprehensive income (loss):
Foreign currency translation adjustments (Note 1)	(2,038)	623	(3,372)	734
Available-for-sale investments:
Unrealized gain (loss) on investments, net of tax effect	(657)	(385)	(137)	712
Other comprehensive income (loss), net of taxes	(2,695)	238	(3,509)	1,446
Comprehensive income (loss)	$ 30,309	$ (49,201)	$ (134,166)	$ 22,599

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Common Stock [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance at Dec. 31, 2018	$ 528,470		$ 854		$ 1,226,453		$ (2,281)		$ (715,827)		$ 19,271
Balance (ASU 2016-02 [Member]) at Dec. 31, 2018		$ 8,688		$ 0		$ 0		$ 0		$ 8,688		$ 0
Balance (ASU 2018-02 [Member]) at Dec. 31, 2018		$ 0		$ 0		$ 0		$ 611		$ (611)		$ 0
Balance, Shares at Dec. 31, 2018			85,432,102
Net income (loss)	21,153		$ 0		0		0		21,153		0
Change in unrealized gain or loss on investments	712		0		0		712		0		0
Foreign currency translation adjustments	734		0		0		734		0		0
Shares issued from stock plans, net of payroll taxes paid	5,096		$ 18		5,078		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			1,778,567
Stock-based compensation	48,865		$ 0		48,865		0		0		0
Balance at Sep. 30, 2019	613,718		$ 872		1,280,396		(224)		(686,597)		19,271
Balance, Shares at Sep. 30, 2019			87,210,669
Balance at Jun. 30, 2019	648,302		$ 868		1,265,783		(462)		(637,158)		19,271
Balance, Shares at Jun. 30, 2019			86,847,072
Net income (loss)	(49,439)		$ 0		0		0		(49,439)		0
Change in unrealized gain or loss on investments	(385)		0		0		(385)		0		0
Foreign currency translation adjustments	623		0		0		623		0		0
Shares issued from stock plans, net of payroll taxes paid	(176)		$ 4		(180)		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			363,597
Stock-based compensation	14,793		$ 0		14,793		0		0		0
Balance at Sep. 30, 2019	613,718		$ 872		1,280,396		(224)		(686,597)		19,271
Balance, Shares at Sep. 30, 2019			87,210,669
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 income (loss)	(130,657)		$ 0		0		0		(130,657)		0
Change in unrealized gain or loss on investments	(137)		0		0		(137)		0		0
Foreign currency translation adjustments	(3,372)		0		0		(3,372)		0		0
Shares issued from stock plans, net of payroll taxes paid	17,240		$ 32		17,208		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			3,227,267
Stock-based compensation	52,451		$ 0		52,451		0		0		0
Balance at Sep. 30, 2020	470,931		$ 909		1,370,384		(4,256)		(915,377)		19,271
Balance, Shares at Sep. 30, 2020			90,884,756
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
Net income (loss)	33,004		$ 0		0		0		33,004		0
Change in unrealized gain or loss on investments	(657)		0		0		(657)		0		0
Foreign currency translation adjustments	(2,038)		0		0		(2,038)		0		0
Shares issued from stock plans, net of payroll taxes paid	7,588		$ 7		7,581		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			656,463
Stock-based compensation	17,891		$ 0		17,891		0		0		0
Balance at Sep. 30, 2020	$ 470,931		$ 909		$ 1,370,384		$ (4,256)		$ (915,377)		$ 19,271
Balance, Shares at Sep. 30, 2020			90,884,756

Condensed Consolidated Statem_5

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net income (loss)	$ (130,657)	$ 21,153
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	8,671	8,715
Amortization of finance lease right-of-use assets	7,886	7,720
Net accretion of discount on investments	103	(3,354)
Unrealized loss on equity investments	(3)	(78)
Investment loss in unconsolidated variable interest entity	13	0
Gain on disposal of property and equipment	(3)	(10)
Stock-based compensation	52,451	48,865
Realized loss on sales of available-for-sale securities	258	0
Changes in operating assets and liabilities:
Accounts receivable, net	2,520	44,459
Inventories	(5,206)	(4,908)
Prepaid expenses and other current assets	121,923	(128,922)
Other assets	7,586	(953)
Accounts payable	1,440	(5,084)
Accrued and other liabilities	3,249	5,484
Deferred revenue	45,925	(50,915)
Accrued interest for finance lease liabilities	(196)	104
Other long-term liabilities	(27,130)	24,069
Net cash provided by (used in) operating activities	88,830	(33,655)
Investing activities
Purchases of property and equipment	(1,604)	(4,017)
Payment made for acquisition	(2,145)	0
Purchases of available-for-sale securities and term deposit	(38)	(155,932)
Proceeds from sales of available-for-sale securities	10,606	0
Proceeds from maturities of investments	301,900	305,000
Net cash provided by (used in) investing activities	308,719	145,051
Financing activities
Repayments of finance lease liabilities	(9,254)	(8,810)
Repayments of lease obligations	(302)	(302)
Cash paid for payroll taxes on restricted stock unit releases	(9,007)	(10,614)
Proceeds from issuance of common stock	26,247	15,710
Net cash provided by (used in) financing activities	7,684	(4,016)
Effect of exchange rate change on cash and cash equivalents	969	(46)
Net increase (decrease) in cash and cash equivalents	406,202	107,334
Total cash and cash equivalents at beginning of period	126,266	89,258
Total cash and cash equivalents at end of period	$ 532,468	$ 196,592

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	1. Significant Accounting Policies Description of Operations FibroGen, Inc. (“FibroGen” or the “Company”) was incorporated in 1993 in Delaware and are 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”), 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 has received marketing authorization in China (tradename: 爱瑞卓 ® The Company’s NDA filing in the United States (“U.S.”) for roxadustat for the treatment of anemia in dialysis and non-dialysis CKD patients was accepted by the U.S. Food and Drug Administration (“FDA”) in February 2020. In Europe, the Marketing Authorization Application (“MAA”) filing for roxadustat for the treatment of anemia in dialysis and non-dialysis CKD patients was accepted for regulatory review by the European Medicines Agency (“EMA”) in May 2020. Roxadustat is in Phase 3 clinical development in the U.S. and Europe and in Phase 2/3 development in China for anemia associated with myelodysplastic syndromes. Roxadustat is in Phase 2 clinical development for chemotherapy-induced anemia. Pamrevlumab, an anti-CTGF human monoclonal antibody, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, pancreatic cancer and Duchenne muscular dystrophy, and is also in Phase 2 development in Severe Acute Respiratory Syndrome Coronavirus 2019 Disease (“COVID-19”). 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. (“FibroGen Cayman”). 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, 2019 (“2019 Form 10-K”). Out-of-Period Adjustments During the third quarter of 2020, the Company recorded out-of-period adjustments that resulted in a net decrease in revenue of $2.1 million. The Company does not believe the correction of these errors is individually or in aggregate material to the consolidated financial statements for the three and nine months ended September 30, 2020 or to any prior period consolidated financial statements. 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. On an ongoing basis, management reviews these estimates and assumptions. Changes in facts and circumstances may alter such estimates and actual results could differ from those estimates. In the Company’s opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of its financial position, results of operations and cash flows for the interim periods presented. Net Income (Loss) per Share The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net income (loss) $ 33,004 $ (49,439 ) $ (130,657 ) $ 21,153 Weighted average shares used to compute net income (loss) per share: Basic 90,558 87,007 89,414 86,390 Dilutive effect of potential common shares 3,120 — — 5,605 Diluted 93,678 87,007 89,414 91,995 Net income (loss) per share: Basic $ 0.36 $ (0.57 ) $ (1.46 ) $ 0.24 Diluted $ 0.35 $ (0.57 ) $ (1.46 ) $ 0.23 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. During the nine months ended September 30, 2020, and the three months ended September 30, 2019, the Company reported a net loss. Therefore, dilutive common shares are not assumed to have been issued since their effect is anti-dilutive. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units and shares to be purchased under the employee stock purchase plan totaling 4.2 million and 9.2 million, respectively, for the three months ended September 30, 2020 and 2019, and totaling 8.9 million and 3.6 million, respectively, for the nine months ended September 30, 2020 and 2019, as they were anti-dilutive. Risks and Uncertainties The Company’s business is subject to risks and uncertainties, including those related to COVID-19 and the related shelter-in-place, stay-at-home and other similar governmental orders issued in response to the COVID-19 pandemic. Starting in the first quarter of 2020, the Company experienced slower enrollment in its clinical trials due to the interruption caused by COVID-19 in the worldwide healthcare system. The future impact of the COVID-19 pandemic on the Company’s business is highly uncertain and difficult to predict. The COVID-19 pandemic may continue to affect enrollment in and initiation of the Company’s clinical trials, and could affect the Company’s supply chain if further social distancing and other business restrictions are put in place by various government entities, particularly in China and the U.S. COVID-19 may affect the health of the Company’s employees limiting the Company’s productivity. The COVID-19 pandemic may also impact the market for the Company’s products and product candidates in the future, affecting sales of the Company’s products. Such possible risks and uncertain impacts from the COVID-19 pandemic could have a material adverse effect on the Company’s drug development, commercialization revenues, and other portions of its business, and in particular, could impact the Company’s assumptions of accounts receivable collectability, fair value measurements of investments, liquidity, and development costs. The extent of the pandemic’s effect on the Company’s operational and financial performance will depend in large part on future developments, particularly with respect to the scope and severity of the pandemic, governmental restrictions put in place to fight the pandemic, and the development of vaccines and treatments for COVID-19. Due to the inherent uncertainty of the unprecedented and rapidly evolving situation, the Company is unable to estimate the likely impact of the COVID-19 pandemic on its future operations. Recently Issued and Adopted Accounting Guidance In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Codification Improvements to Topic 326, Financial Instruments-Credit Losses , Recently Issued Accounting Guidance Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes 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 2019 Form 10-K, except for the following: Variable Interest Entity Under the Accounting Standards Codification (“ASC”) 810, Consolidation Foreign currency translation Prior to April 1, 2020, the functional currency of the Company’s subsidiary, FibroGen (China) Medical Technology Development Co., Ltd. (“FibroGen Beijing”), was the U.S. dollar. Accordingly, monetary assets and liabilities of FibroGen Beijing in the currencies other than USD were remeasured using exchange rates in effect at the end of the period. Revenues and costs in its local currency, Renminbi Yuan (“CNY”), were remeasured using average exchange rates for the period, except for costs related to those balance sheet items that were remeasured using historical exchange rates. The resulting remeasurement gains and losses were included within interest income and other, net in the consolidated statements of operations as incurred. On April 1, 2020, FibroGen Beijing adopted CNY as its functional currency based on reassessment of the primary economic operational environment of FibroGen Beijing that is mainly associated with its growing manufacturing and product sales activities conducted in CNY. As such, monetary assets and liabilities of FibroGen Beijing in currencies other than CNY are remeasured using exchange rates in effect at the end of the period. The assets and liabilities are translated to U.S. dollars at exchange rates in effect at the balance sheet date. All income statement accounts are translated at monthly average exchange rates. Resulting foreign currency translation adjustments are recorded directly in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity. This change in FibroGen Beijing’s functional currency was accounted for prospectively from April 1, 2020, and the prior condensed consolidated financial statements were not restated. The related currency translation adjustment was $1.3 million at April 1, 2020, upon adoption. Trade accounts receivable The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts. The Company makes estimates of expected credit losses for the allowance for doubtful accounts by considering factors such as historical experience, credit quality, the age of the accounts receivable balances, current economic and regulatory conditions that may affect a customer’s ability to pay, and estimates of expected future losses. The Company’s bad debt expense for the three and nine months ended September 30, 2020 and the allowance for doubtful accounts as of September 30, 2020 were immaterial. Credit losses – Available-for-sale debt securities The Company periodically assesses its available-for-sale investments for other-than-temporary impairment. For debt securities in an unrealized loss position, the Company first considers its intent to sell, or whether it is more likely than not that the Company will be required to sell the debt securities before recovery of their amortized cost basis. If either of these criteria are met, the amortized cost basis of such debt securities is written down to fair value through interest and other, net. For debt securities in an unrealized loss position that do not meet the aforementioned criteria, the Company assesses whether the decline in the fair value of such debt securities has resulted from credit losses or other factors. The Company considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and any adverse conditions specifically related to the securities, among other factors. If this assessment indicates that a credit loss may exist, the Company then compares the present value of cash flows expected to be collected from such securities to their amortized cost basis. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded through interest and other, net, limited by the amount that the fair value is less than the amortized cost basis. Any additional impairment not recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are recorded as provision for, or reversal of, credit loss expense. Losses are charged against the allowance when the Company believes that an available-for-sale security is confirmed uncollectable or when either of the criteria regarding intent or requirement to sell is met. Product revenue, net The Company sells roxadustat in China through a number of pharmaceutical distributors located in China. 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 a general 60-day payment term. As such, product revenue is not adjusted for the effects of a significant financing component. Product rev enue is recorded at the net sales prices (transaction price) which includes the following estimates of variable consideration: • Price adjustment: In December 2019, China’s National Healthcare Security Administration released price guidance for roxadustat under the National Reimbursement Drug List (“NRDL”), effective January 1, 2020. Any channel inventories as of January 1, 2020 that had not been sold to hospitals by distributors, or to patients by hospitals, were eligible for a price adjustment under the price protection. The price adjustment is calculated based on estimated channel inventory levels at January 1, 2020. If price guidance changes in the future, the price adjustment will be calculated in the same manner; • Contractual sales rebate : The contractual sales rebate is calculated based on the stated percentage of gross sales by each distributor in the distribution agreement entered between FibroGen and each distributor. The contractual sales rebate is recorded as a reduction to revenue at the point of sale to the distributor; • Key account hospital sales rebate : An additional sales rebate is provided to a distributor for product sold to key account hospitals as a percentage of gross sales made by the distributor to eligible hospitals. This additional rebate is recorded as a reduction to revenue at the point of sale to the distributor; • Transfer fee discount : The transfer fee discount is offered to a distributor who has its downstream distributors supply to eligible hospitals. This discount is calculated based on a percentage of gross sales made to the downstream distributors, and recorded as a reduction to revenue as incurred; • 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. The Company, at its sole discretion, decides whether to accept such return request; and • Non-key account hospital listing award: A one-time fixed-amount award is offered to a distributor who successfully lists the product with an eligible hospital, and who meets certain requirements. The Company considers this particular award to be an upfront payment to a customer within the definitions of ASC 606. The non-key account hospital listing award is capitalized when the distributor meets eligibility requirements, and amortized as reduction to product revenue over future sales orders made by the distributor until exhausted. 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. The distributor’s legal right of offset is calculated at the individual distributor level.

Acquisition and Variable Intere

Acquisition and Variable Interest Entity	9 Months Ended
	Sep. 30, 2020
Acquisition And Variable Interest Entity [Abstract]
Acquisition and Variable Interest Entity	2. Acquisition and Variable Interest Entity On July 8, 2020, FibroGen Cayman, FibroGen Beijing, and FibroGen International (Hong Kong) Limited (collectively, “FibroGen China”) and AstraZeneca AB (“AstraZeneca”) entered into an amendment, effective July 1, 2020, to the collaboration agreement for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in China (“China Agreement”), relating to the development and commercialization of roxadustat in China (the “China Amendment”). The China Amendment provides for the establishment of a jointly owned entity that will perform roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. To prepare for the establishment of this jointly owned entity, in July 2020, FibroGen Beijing acquired 100% of the outstanding shares of Beijing Kangda Yongfu Pharmaceutical Co., LTD (“Kangda”) in exchange for cash consideration of CNY15.0 million (approximately $2.1 million). The purpose of the acquisition was to acquire a distribution license owned by Kangda for commercializing and distributing roxadustat in China. FibroGen Beijing will continue to hold all of the regulatory licenses issued by China regulatory authorities and will continue to be primarily responsible for regulatory, clinical, manufacturing, medical affairs and pharmacovigilance. The transaction costs related to the execution of the acquisition, primarily legal expenses, totaled CNY5.0 million and were shared equally with AstraZeneca. Therefore, the acquisition costs for FibroGen Beijing were CNY2.5 million (approximately $0.4 million). Under the ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business On September 15, 2020, FibroGen Beijing and AstraZeneca entered into an equity transfer agreement and shareholders agreement, under which FibroGen Beijing sold 48.9% of the outstanding shares of Kangda to AstraZeneca in exchange for cash consideration of CNY7.3 million (approximately $1.0 million). Concurrently with the equity transfer, the two parties renamed Kangda to Beijing Falikang Pharmaceutical Co. Ltd. (“Falikang”). Following the sale, FibroGen Beijing owns 51.1% of the outstanding shares of Falikang. The gain (loss) resulting from the equity transfer was immaterial. Pursuant to the guidance under ASC 810, the Company concluded that Falikang qualifies as a VIE. As Falikang is a distribution entity for roxadustat and AstraZeneca is the final decision maker for all the roxadustat commercialization activities, the Company lacks the power criterion while AstraZeneca meets both the power and economic criteria under ASC 810, to direct the activities of Falikang that most significantly impact its performance. Therefore, the Company is not the primary beneficiary of this VIE. As a result, the Company accounted for its investment in Falikang under the equity method, and Falikang is not consolidated into the Company’s condensed consolidated financial statements. Accordingly, The Company recorded its investment in Falikang of CNY10.2 million (approximately $1.5 million), which is the total of the 51.1% of Falikang’s equity and the acquisition costs, as an investment in unconsolidated subsidiary in other assets in the condensed consolidated balance sheet. In addition, the Company recognized its proportionate share of the reported profits or losses of Falikang, beginning September 15, 2020, as other income (loss) in the condensed consolidated statement of operations, and as an adjustment to its investment in unconsolidated subsidiary in the condensed consolidated balance sheet. Falikang has not incurred material profit or loss to date. The Company will assess the impairment of its equity method investment whenever events or changes in circumstances indicate that a decrease in value of the investment has occurred that is other than temporary. The Company may be required to provide shareholder loans to Falikang to meet necessary financial obligations as part of its operations. To date, these loans have been immaterial. On an ongoing basis, the Company will re-evaluate the VIE assessment based on potential changes in facts and circumstances, including but not limited to, the shareholder loans received by Falikang and the execution of any future significant agreements between Falikang and its shareholders and/or other third parties. As of September 30, 2020, the Company’s equity method investment in Falikang was $1.5 million. Falikang is considered as a related party to the Company. See Note 9, Related Party Transactions As of September 30, 2020, the cash consideration of CNY7.3 million for the above equity transfer, together with AstraZeneca’s share of the acquisition costs of CNY2.5 million, totaling CNY9.8 million (approximately $1.4 million), was recorded as a receivable from AstraZeneca in prepaid expenses and other current assets in the condensed consolidated balance sheet. In October 2020, CNY7.3 million cash consideration was received.

Collaboration Agreements and Re

Collaboration Agreements and Revenues	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements and Revenues	3. 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 aggregate amount of consideration received through September 30, 2020 totals $90.1 million. The Japan Agreement also provides for tiered payments based on net sales of roxadustat in the low 20% range after commercial launch. 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 roxadustat in the low 20% range. The aggregate amount of consideration received through September 30, 2020 totals $540.0 million. During the second quarter of 2019, the Company received positive topline results from analyses of pooled major adverse cardiac event (“MACE”) and MACE plus hospitalized unstable angina and hospitalized congestive heart failure (“MACE+”) data from its Phase 3 trials evaluating roxadustat as a treatment for dialysis and non-dialysis CKD patients, enabling Astellas to prepare for an MAA submission to the EMA, following the Company’s NDA submission to the FDA. These milestones became probable of being achieved in the second quarter of 2019, and the total consideration of $130.0 million associated with these milestones was included in the transaction price and allocated to performance obligations under the Europe Agreement in the second quarter of 2019, of which $128.8 million was recognized as revenue during 2019, and $0.6 million was recognized as revenue during the nine months ended September 30, 2020, from performance obligations satisfied or partially satisfied. According to the Europe Agreement, these milestone payments were billed to Astellas upon the submission of an MAA in the second quarter of 2020 and the total $130.0 million was received during the same quarter. 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, $15.0 million of which was received in 2015 as a result of the finalization of its two audited pre-clinical carcinogenicity study reports, and the remaining $50.0 million was received in April 2020 as a result of the NDA submission milestone, (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 through September 30, 2020 totals $439.0 million. As mentioned above, during the second quarter of 2019, the Company received positive topline results from analyses of pooled MACE and MACE+ data from its Phase 3 trials for roxadustat, enabling the Company’s NDA submission to the FDA. The regulatory milestone payment associated with this NDA submission became probable of being achieved in the second quarter of 2019. Accordingly, the consideration of $50.0 million associated with this milestone was included in the transaction price and allocated to performance obligations under the U.S./ RoW Agreement in the second quarter of 2019, of which $42.4 million was recognized as revenue during 2019, and $0.6 million was recognized as revenue during the nine months ended September 30, 2020, from performance obligations satisfied or partially satisfied. The Company submitted such NDA in December 2019, which was accepted by the FDA for review in February 2020. According to the U.S/RoW Agreement, this milestone payment is billable to AstraZeneca when the NDA is accepted by the FDA. Therefore, this $50.0 million was billed during the first quarter of 2020, the payment of which was fully received in April 2020. AstraZeneca and Astellas approved the development of roxadustat for the treatment of chemotherapy-induced anemia in December 2018 and January 2019, respectively. Costs associated with the development of this indication are expected to be shared 50/50 between AstraZeneca and Astellas. In addition, in December 2018, anemia of chronic inflammation and multiple myeloma was approved for development by AstraZeneca and is expected to be fully funded by them. For revenue recognition purposes, the Company concluded that the addition of these new indications represents a modification to the collaboration agreements and will be accounted for separately, meaning the development costs associated with the new indications are distinct from the original development costs. The development service period for roxadustat for the treatment of chemotherapy-induced anemia, anemia of chronic inflammation and multiple myeloma under the AstraZeneca agreements is estimated to continue through the end of 2024, to allow for development of these additional indications. China Agreement Effective July 30, 2013, the Company (through its subsidiaries affiliated with China) entered into the 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 was 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. The aggregate amount of such consideration received for milestone and upfront payments through September 30, 2020 totals $77.2 million. In December 2019, roxadustat was included on the updated NRDL released by China’s National Healthcare Security Administration for the treatment of anemia in CKD, covering patients who are non-dialysis dependent as well as those who are dialysis-dependent. The inclusion on the NRDL triggered a total of $22.0 million of milestones payable to the Company by AstraZeneca. Accordingly, the total consideration of $22.0 million associated with these milestones was included in the transaction price and allocated to performance obligations under the China Agreement during the fourth quarter of 2019. This milestone payment was received during the first quarter of 2020. China Amendment On July 8, 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 will perform roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. See Note 2, Acquisition and Variable Interest Entity In accordance with the China Amendment, the Company is currently in the interim period. Under the China Amendment, the interim period is defined as the period from April 1, 2020 to the time when Falikang is fully operational, expected in early 2021. During the interim period, FibroGen will continue to sell product directly to the distributors, who remain as the Company’s customers. Under the China Amendment, the calculation for profit or loss share has changed related to sales of roxadustat in China 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. Once Falikang is fully operational, AstraZeneca will bill the co-promotion expenses to Falikang, rather than FibroGen Beijing. In addition, FibroGen Beijing will manufacture and supply commercial product to Falikang based on an agreed upon transfer price. Development costs will continue to be shared 50/50 between the Parties. As a result, the interim period primarily includes the following activities : • Co-promotion expenses: The China Amendment revised the payment arrangements and calculation of the historical unpaid co-promotion expenses to AstraZeneca for its sales and marketing efforts associated with the commercial sales for roxadustat in China since the product launch. Under the previous China Agreement, payment of these historical co-promotion expenses was subject to certain profitability and cash flow thresholds. No amount of the historical co-promotion costs had been paid prior to the China Amendment as these thresholds had not yet been met. Under the China Amendment, a portion of the historical unpaid co-promotion expenses was adjusted to reduce the amount owed by FibroGen Beijing and the current period co-promotion expenses are capped at a percentage of net roxadustat sales in China. As a result, in the third quarter of 2020, the Company reversed approximately $84.4 million of previously accrued co-promotion expenses payable, which was recorded as a reduction to selling, general and administrative expenses, where these expenses were initially recorded during the periods from the initiation of commercial activities in the first quarter of 2019 to the second quarter of 2020. The co-promotion expenses for the three and nine months ended September 30, 2020, capped at a percentage of net roxadustat sales in China, were $8.8 million and $14.8 million, respectively, included in the selling, general and administrative expenses. After this adjustment, as of September 30, 2020, $14.8 million of the recalculated accrued co-promotion expenses was recorded as a current liability, as it is anticipated to be paid within the next 12 months ; and $26.3 million of the recalculated accrued co-promotion expenses remained in the long-term liabilities, as it is not anticipated to be paid within the next 12 months . • Profit share: Profit/loss share between FibroGen China and AstraZeneca is based on a calculation of the current period net roxadustat sales in China and deductible expenses pursuant to the China Agreement. Based on the calculation, a profit was achieved during the third quarter of 2020. As a result, the Company recorded a profit share liability of $2.0 million to AstraZeneca in the three months ended September 30, 2020 in the condensed consolidated statement of operations. Summary of Revenue Recognized Under the Collaboration Agreements The table below summarizes the accounting treatment for the various performance obligations pursuant to each of the Astellas and AstraZeneca agreements. License amounts identified below are included in the “License revenue” line item in the condensed consolidated statements of operations. All other elements identified below are included in the “Development and other revenue” line item in the condensed consolidated statements of operations. Amounts recognized as revenue under the Japan Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Performance Obligation 2020 2019 2020 2019 Japan License revenue $ — $ 11,935 $ — $ 11,935 Development revenue $ 86 $ 537 $ 413 $ 1,151 The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Japan Agreement, along with any associated deferred revenue as follows (in thousands): Japan Agreement Cumulative Revenue Through September 30, 2020 Deferred Revenue at September 30, 2020 Total Consideration Through September 30, 2020 License $ 86,024 $ — $ 86,024 Development revenue 15,543 164 15,707 Total license and development revenue $ 101,567 $ 164 $ 101,731 The revenue recognized under the Japan Agreement for the three months ended September 30, 2020 included an increase in revenue of $0.1 million resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods. The remainder of the transaction price related to the Japan Agreement includes no further variable consideration from estimated future co-development billing. Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Performance Obligation 2020 2019 2020 2019 Europe License revenue $ — $ — $ — $ 117,470 Development revenue $ 4,651 $ 2,996 $ 13,827 $ 24,463 The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Europe Agreement, along with any associated deferred revenue as follows (in thousands): Europe Agreement Cumulative Revenue Through September 30, 2020 Deferred Revenue at September 30, 2020 Total Consideration Through September 30, 2020 License $ 487,951 $ — $ 487,951 Development revenue 244,834 2,096 246,930 Total license and development revenue $ 732,785 $ 2,096 $ 734,881 The revenue recognized under the Europe Agreement for the three months ended September 30, 2020 included an increase in revenue of $1.3 million resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods. The remainder of the transaction price related to the Europe Agreement includes $31.5 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 were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Performance Obligation 2020 2019 2020 2019 U.S. / RoW and China License revenue $ — $ — $ — $ 33,112 Development revenue 15,220 17,106 43,525 59,872 China performance obligation $ 706 $ 19 $ 1,300 $ 19 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, along with any associated deferred revenue as follows (in thousands): U.S. / RoW and China Agreements Cumulative Revenue Through September 30, 2020 Deferred Revenue at September 30, 2020 Total Consideration Through September 30, 2020 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 536,792 2,435 539,227 China performance obligation 1,390 141,171 142,561 Total license and development revenue $ 880,026 $ 143,606 $ 1,023,632 The revenue recognized under the U.S./RoW Agreement for the three months ended September 30, 2020 included a decrease of $0.6 million in revenue resulting from changes to estimated variable consideration in the current period relating to performance obligations satisfied or partially satisfied in previous periods. The remainder of the transaction price related to the U.S./RoW Agreement and China Agreement includes $52.3 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, which are expected to be recognized in a pattern consistent with estimated deliveries of the commercial drug product. As mentioned above, a profit share with AstraZeneca of $2.0 million was recorded in the condensed consolidated statement of operations for the three months ended September 30, 2020. Product Revenue, Net Product revenue from roxadustat commercial sales 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. Product revenue, net was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Gross revenue $ 27,900 $ 622 $ 53,105 $ 622 Non-key account hospital listing award (2,930 ) — (5,495 ) — Contractual sales rebate (1,966 ) (43 ) (3,714 ) (43 ) Other discounts and rebates (313 ) — (512 ) — Sales return (8 ) — (53 ) — Product revenue, net $ 22,683 $ 579 $ 43,331 $ 579 In the second quarter of 2020, the Company amended the agreement with its pharmaceutical distributors, which triggered accounting modifications particularly related to non-key account hospital listing award. For the three and nine months ended September 30, 2020, the non-key account hospital listing award was $2.9 million and $5.5 million, respectively, which was recorded as a reduction to the revenue and calculated based on eligible non-key account hospital listing to date achieved by each distributor with certain requirements met during the period. For the three and nine months ended September 30, 2020, the contractual sales rebate was $2.0 million and $3.7 million, respectively, which were calculated based on the stated percentage of gross sales by each distributor in the distribution agreement entered between FibroGen and each distributor. All other rebates and discounts, including sales return allowance were immaterial for the periods presented. 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 distributor’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. The distributor’s legal right of 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, 2019 Additions Deduction Currency Translation and Other Gross Contract Liabilities Balance Balance Presented Net Against Accounts Receivable Balance at September 30, 2020 Contract liabilities $ (1,102 ) $ (10,623 ) $ 450 $ (117 ) $ (11,392 ) $ 9,759 $ (1,633 ) As of September 30, 2020, the total rebates and discounts as reductions to gross accounts receivable was $9.8 million, and the total contract liabilities was $1.6 million, which was included in accrued and other current liabilities in the condensed consolidated balance sheet. The reductions to gross accounts receivable, including the above-mentioned contra-accounts receivable items related to product revenue, consisted of the following (in thousands): September 30, 2020 December 31, 2019 Price adjustment $ 529 $ 936 Contractual sales rebate 3,479 148 Non-key account hospital listing award 5,238 — Other discounts and rebates 513 18 Sales return 53 — Provision for credit loss 102 — Total reductions to gross accounts receivable $ 9,914 $ 1,102 Drug Product Revenue Drug product revenue was as follows (in thousands): Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Astellas $ (3,957 ) $ 4,281 AstraZeneca 4,643 4,643 Drug product revenue $ 686 $ 8,924 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 deliver to Astellas roxadustat active pharmaceutical ingredient (“API”) for the roxadustat commercial launch in Japan. Related to the API shipments in 2018 under the Japan Amendment, during the three months ended September 30, 2020, the Company recorded a $4.0 million reduction to drug product revenue, related to a change in estimated variable consideration. Specifically, the change in estimated variable consideration was based on the API held by Astellas at March 31, 2020 adjusted to reflect the updated listed price for roxadustat issued by the Japanese Ministry of Health, Labour and Welfare and changes in the estimated bulk product strength mix intended to be manufactured by Astellas, estimated cost to convert the API to bulk product tablets, and estimated yield from the manufacture of bulk product tablets, among others. During the three months ended June 30, 2020, the Company fulfilled delivery obligations under the term of the Japan Amendment, and recognized the related drug product revenue of $8.2 million in the same period. The amount represents variable consideration and was estimated based on the quantity of product shipped, actual listed price for roxadustat issued by the Japanese Ministry of Health, Labour and Welfare and possible future changes to the listed price, adjusted for 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. Under the U.S./RoW Agreement, FibroGen would manufacture and deliver to AstraZeneca roxadustat bulk drug product in support of commercial supplies. The Company delivered bulk drug product to AstraZeneca as pre-commercial supply for process validation purposes in the three months ended March 31, 2020, June 30, 2020 and September 30, 2020, respectively. The related drug product revenue of $4.6 million was recognized in the three months ended September 30, 2020. The drug product revenue amount represents variable consideration and was estimated based on the quantity of product shipped and an estimated price. The amount of variable consideration that is included in the transaction price may be constrained, and is included in the drug product revenue 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. Actual amounts of consideration ultimately received in the future may differ from the Company’s estimates, for which the Company will adjust these estimates and affect the drug product revenue in the period such variances become known. Other Revenues Other revenues consist primarily of collagen material sold for research purposes. Other revenues were immaterial for all periods presented. Deferred Revenue Deferred revenue represents amounts billed, or in certain cases, yet to be billed to the Company’s collaboration partners for which the related revenues have not been recognized because one or more of the revenue recognition criteria have not been met. The current portion of deferred revenue represents the amount to be recognized within one year from the balance sheet date based on the estimated performance period of the underlying performance obligations. The long-term portion of deferred revenue represents amounts to be recognized after one year through the end of the non-contingent performance period of the underlying performance obligations. Deferred revenue includes amounts allocated to the China unit of accounting under the AstraZeneca arrangement as revenue recognition associated with this unit of accounting is tied to the commercial sales of the products within China. As of September 30, 2020, approximately $3.2 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.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
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): September 30, 2020 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 125,388 $ — $ — $ 125,388 Equity investments 247 — — 247 Money market funds 451,917 — — 451,917 Certificate of deposit — 30,010 — 30,010 Total $ 577,552 $ 30,010 $ — $ 607,562 December 31, 2019 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 347,383 $ 80,123 $ — $ 427,506 Bond and mutual funds 10,816 — — 10,816 Equity investments 255 — — 255 Money market funds 85,551 — — 85,551 Certificate of deposit — 30,032 — 30,032 Total $ 444,005 $ 110,155 $ — $ 554,160 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. The fair values of the Company’s financial liabilities that are carried at historical cost are as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,242 $ 1,242 December 31, 2019 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,544 $ 1,544 The fair values of the Company’s financial liabilities 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	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	5. Leases The Company’s lease assets and related lease liabilities were as follows (in thousands): Balance Sheet Line Item September 30, 2020 December 31, 2019 Assets Finance: Right-of-use assets - cost $ 50,220 $ 49,909 Accumulated amortization (18,192 ) (10,307 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 32,028 39,602 Operating: Right-of-use assets - cost 2,796 2,736 Accumulated amortization (1,554 ) (805 ) Operating lease right-of-use assets, net Other assets 1,242 1,931 Total lease assets $ 33,270 $ 41,533 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 12,311 $ 12,351 Operating lease liabilities Accrued and other current liabilities 770 983 Non-current: Finance lease liabilities Finance lease liabilities, non-current 28,514 37,610 Operating lease liabilities Other long-term liabilities 472 942 Total lease liabilities $ 42,067 $ 51,886 The components of lease expense were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Statement of Operations Line Item 2020 2019 2020 2019 Finance lease cost: Amortization of right-of-use assets Cost of goods sold; Research and development; Selling, general and administrative expenses $ 2,639 $ 2,580 $ 7,886 $ 7,720 Interest on lease liabilities Interest expense 462 578 1,511 1,826 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 304 290 868 579 Sublease income Selling, general and administrative expenses (301 ) (310 ) (899 ) (1,135 ) Total lease cost $ 3,104 $ 3,138 $ 9,366 $ 8,990 Supplemental cash flow information related to leases were as follows (in thousands): Nine Months Ended September 30, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 812 $ 540 Operating cash flows from finance leases 1,468 1,640 Financing cash flows from finance leases 9,254 8,810 Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 434 49,784 Operating leases $ 55 $ 2,723 Lease term and discount rate were as follows: September 30, 2020 December 31, 2019 Weighted-average remaining lease term (years): Finance leases 3.1 3.6 Operating leases 1.6 2.1 Weighted-average discount rate: Finance leases 4.39 % 4.42 % Operating leases 4.73 % 4.75 % Maturities of lease liabilities as of September 30, 2020 are as follows (in thousands): Year Ending Finance Leases Operating Leases 2020 (Remaining three month period) $ 3,542 $ 245 2021 13,683 714 2022 13,883 329 2023 12,524 — Total future lease payments 43,632 1,288 Less: Interest (2,807 ) (46 ) Present value of lease liabilities $ 40,825 $ 1,242

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	6. Balance Sheet Components Cash and Cash Equivalents Cash and cash equivalents consisted of the following (in thousands): September 30, 2020 December 31, 2019 Cash $ 80,551 $ 40,715 Money market funds 451,917 85,551 Total cash and cash equivalents $ 532,468 $ 126,266 The underlying investments in the money market funds as of September 30, 2020 are all US government obligations. At September 30, 2020 and December 31, 2019, a total of $51.2 million and $11.9 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, marketable equity investments, term deposit and certificate of deposit. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s investments by major investments type are summarized in the tables below (in thousands): September 30, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 124,993 $ 395 $ — $ 125,388 Certificates of deposit 30,000 10 — 30,010 Equity investments 125 122 — 247 Total investments $ 155,118 $ 527 $ — $ 155,645 December 31, 2019 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 426,995 $ 536 $ (25 ) $ 427,506 Certificates of deposit 30,000 32 — 30,032 Bond and mutual funds 10,730 86 — 10,816 Equity investments 125 130 — 255 Total investments $ 467,850 $ 784 $ (25 ) $ 468,609 At September 30, 2020, all of the available-for-sale investments had contractual maturities within one year. During the three and nine months ended September 30, 2020 and 2019, the Company did not recognize any other-than-temporary impairment loss. Inventories Inventories consisted of the following (in thousands): September 30, 2020 December 31, 2019 Raw materials $ 1,152 $ 325 Work-in-progress 5,616 2,264 Finished goods 5,034 4,298 Total inventories $ 11,803 $ 6,887 The provision to write-down excess and obsolete inventory was immaterial for the three and nine months ended September 30, 2020. There was no provision to write-down excess and obsolete inventory for the three and nine months ended September 30, 2019. Prepaid expenses and other current assets Prepaid expenses and other current assets consisted of the following (in thousands): September 30, 2020 December 31, 2019 Unbilled contract assets $ — $ 180,000 Deferred revenues from associated contracts — (54,790 ) Net unbilled contract assets — 125,210 Prepaid assets 5,549 6,464 Other current assets 6,014 1,717 Total prepaid expenses and other current assets $ 11,563 $ 133,391 The unbilled contract assets as of December 31, 2019 included two regulatory milestones totaling $130.0 million under the Europe Agreement with Astellas associated with the planned MAA submission in Europe. The MAA was submitted in the second quarter of 2020. Therefore, the $130 million milestones were billed in the same quarter. The unbilled contract assets as of December 31, 2019 also included a $50.0 million regulatory milestone under the U.S./RoW Agreement with AstraZeneca associated with the NDA submission in the U.S, which was submitted in December 2019 and accepted for review in February 2020. Therefore, the $50.0 million milestone was billed during the first quarter of 2020. See Note 3, Collaboration Agreements and Revenues, Property and Equipment Property and equipment consisted of the following (in thousands): September 30, 2020 December 31, 2019 Leasehold improvements $ 101,162 $ 101,548 Laboratory equipment 17,890 17,329 Machinery 8,012 8,217 Computer equipment 9,124 8,399 Furniture and fixtures 6,110 5,822 Construction in progress 1,506 1,792 Total property and equipment $ 143,804 $ 143,107 Less: accumulated depreciation (107,651 ) (100,364 ) Property and equipment, net $ 36,153 $ 42,743 Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following (in thousands): September 30, 2020 December 31, 2019 Preclinical and clinical trial accruals $ 29,396 $ 16,279 API product price adjustment 3,957 36,324 Payroll and related accruals 19,606 19,784 Accrued co-promotion expenses - current 14,836 — Property taxes and other 6,057 2,044 Professional services 7,384 4,842 Other 9,336 4,543 Total accrued and other current liabilities $ 90,572 $ 83,816 The API product price adjustment of $36.3 million accrued as of December 31, 2019 was related to the change in estimated variable consideration of API product at the time the roxadustat listed price was issued by the Japanese Ministry of Health, Labour and Welfare in the fourth quarter of 2019. This amount was fully paid during the first quarter of 2020. The API product price adjustment of $4.0 million accrued as of September 30, 2020 related to the change in estimated variable consideration of API product at the time an updated roxadustat listed price was issued by the same Japanese authority in the first quarter of 2020. See Note 3, Collaboration Agreements and Revenues, On July 8, 2020, the Parties entered into an amendment to the China Agreement, relating to the development and commercialization of roxadustat in China, which revised, among other things, the arrangements and calculation of the estimated co-promotion expenses payable to AstraZeneca for its sales and marketing efforts associated with the commercial sales for roxadustat in China. As a result, the previously accrued long-term co-promotion expenses were significantly reduced during the third quarter of 2020. $14.8 million of the recalculated accrued co-promotion expenses is anticipated to be paid within the next 12 months, therefore was recorded as a current liability as of September 30, 2020. Other Long-term Liabilities Other long-term liabilities consisted of the following (in thousands): September 30, 2020 December 31, 2019 Accrued long-term co-promotion expenses $ 26,344 $ 53,071 Other long-term tax liabilities 8,637 8,913 Operating lease liabilities, non-current 472 942 Other 2,186 1,340 Total other long-term liabilities $ 37,639 $ 64,266 As mentioned above, the China Amendment revised the arrangements and calculation of the estimated co-promotion expenses payable to AstraZeneca. As a result, we reversed approximately $84.4 million of previously accrued long-term co-promotion expenses during the third quarter of 2020. $26.3 million of the recalculated accrued co-promotion expenses remained in the long-term liabilities as of September 30, 2020, as it is not anticipated to be paid within the next 12 months.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2020
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 September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Research and development $ 11,236 $ 10,185 $ 32,653 $ 30,214 Selling, general and administrative 6,655 4,608 19,798 18,651 Total stock-based compensation expense $ 17,891 $ 14,793 $ 52,451 $ 48,865 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 September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Stock Options Expected term (in years) 5.6 5.3 5.7 5.3 Expected volatility 59.0 % 67.8 % 67.7 % 67.9 % Risk-free interest rate 0.3 % 1.7 % 0.8 % 2.4 % Expected dividend yield — — — — Weighted average estimated fair value $ 22.48 $ 25.17 $ 18.11 $ 32.44 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Expected volatility 50.4 - 77.1 % 48.1 - 62.1 % 49.5 - 77.1 % 48.1 - 62.1 % Risk-free interest rate 0.2 - 2.9 % 1.6 - 2.9 % 0.2 - 2.9 % 1.3 - 2.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 17.00 $ 19.27 $ 17.74 $ 19.53

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes Provision for income tax for the three and nine months ended September 30, 2020 and 2019 were primarily due to foreign taxes. Based upon the weight of available evidence, which includes its historical operating performance, reported cumulative net losses since inception, the Company has established and continues to maintain a full valuation allowance against its 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	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	9. Related Party Transactions Astellas is an equity investor in the Company and considered a related party. The Company recorded revenue related to collaboration agreements with Astellas of $4.7 million and $15.5 million for the three months ended September 30, 2020 and 2019, respectively, and $14.2 million and $155.0 million for the nine months ended September 30, 2020 and 2019, respectively. The drug product revenue from Astellas for the three months ended September 30, 2020 represented a change in estimated variable consideration at the time an updated listed price for roxadustat was issued by the Japanese Ministry of Health, Labour and Welfare, which resulted in a $4.0 million reduction to revenue, related to roxadustat API sales in 2018. See Note 3, Collaboration Agreements and Revenues The Company recorded expense related to collaboration agreements with Astellas of $0.2 million and $0.9 million during the three months ended September 30, 2020 and 2019, respectively, and $0.5 million and $2.2 million during the nine months ended September 30, 2020 and 2019, respectively. As of September 30, 2020 and December 31, 2019, accounts receivable from Astellas were $4.7 million and $4.8 million, respectively, and amounts due to Astellas were $4.1 million and $36.9 million, respectively, which included $4.0 million and $36.3 million of changes in estimated variable consideration related to the API product revenue recognized in 2018, at the time the roxadustat listed price was issued or updated by the Japanese Ministry of Health, Labour and Welfare in the first quarter of 2020 and the fourth quarter of 2019. The $36.3 million was fully paid during the first quarter of 2020. Prepaid expenses and other current assets as of December 31, 2019 included $125.2 million of net unbilled contract assets from Astellas, representing a $130.0 million unbilled contract asset related to two regulatory milestones under the Europe Agreement with Astellas associated with the planned MAA submission to the EMA, net of $4.8 million of associated deferred revenue. According to the Europe Agreement, this $130.0 million was billed to Astellas upon the submission of an MAA in the second quarter of 2020. See Note 3, Collaboration Agreements and Revenues In September 2020, FibroGen Beijing and AstraZeneca completed the establishment of a jointly owned entity, Falikang, which was determined to be an unconsolidated VIE. As such, Falikang is accounted for as an equity method investment, and considered as a related party to the Company. The Company’s investment in Falikang was approximately $1.5 million, which is the total of the 51.1% of Falikang’s equity and the acquisition costs. In addition, the Company recognized its proportionate share of the reported profits or losses of Falikang, beginning September 15, 2020, as other income (loss) in the condensed consolidated statement of operations, and as an adjustment to its investment in unconsolidated subsidiary in the condensed consolidated balance sheet. Falikang has not incurred material profit or loss to date. As of September 30, 2020, the Company’s other assets included $1.5 million of its equity investment in Falikang, and prepaid expenses and other current assets included its miscellaneous receivables of $0.2 million from Falikang. See Note 2, Acquisition and Variable Interest Entity

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Contract Obligations As of September 30, 2020, the Company had outstanding total non-cancelable contract obligations of $33.1 million, including $16.7 million for manufacture and supply of roxadustat, $10.9 million for future milestone payments for research and pre-clinical stage development programs, and $5.5 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. 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 September 30, 2020, as it could not predict the ultimate outcome of these matters, or reasonably estimate the potential exposure. Indemnification Agreements The Company enters into standard indemnification arrangements in the ordinary course of business, including for example, service, manufacturing and collaboration agreements. Pursuant to these arrangements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, including in connection with intellectual property infringement claims by any third party with respect to its technology. The term of these indemnification agreements is generally perpetual any time after the execution of the agreement. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the extent permissible under applicable law. The maximum potential amount of future payments the Company could be required to make under these arrangements is not determinable. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, the Company believes the estimated fair value of these arrangements is minimal.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Description of Operations	Description of Operations FibroGen, Inc. (“FibroGen” or the “Company”) was incorporated in 1993 in Delaware and are 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”), 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 has received marketing authorization in China (tradename: 爱瑞卓 ® The Company’s NDA filing in the United States (“U.S.”) for roxadustat for the treatment of anemia in dialysis and non-dialysis CKD patients was accepted by the U.S. Food and Drug Administration (“FDA”) in February 2020. In Europe, the Marketing Authorization Application (“MAA”) filing for roxadustat for the treatment of anemia in dialysis and non-dialysis CKD patients was accepted for regulatory review by the European Medicines Agency (“EMA”) in May 2020. Roxadustat is in Phase 3 clinical development in the U.S. and Europe and in Phase 2/3 development in China for anemia associated with myelodysplastic syndromes. Roxadustat is in Phase 2 clinical development for chemotherapy-induced anemia. Pamrevlumab, an anti-CTGF human monoclonal antibody, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis, pancreatic cancer and Duchenne muscular dystrophy, and is also in Phase 2 development in Severe Acute Respiratory Syndrome Coronavirus 2019 Disease (“COVID-19”).
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. (“FibroGen Cayman”). 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, 2019 (“2019 Form 10-K”).
Out-of-Period Adjustments	Out-of-Period Adjustments During the third quarter of 2020, the Company recorded out-of-period adjustments that resulted in a net decrease in revenue of $2.1 million. The Company does not believe the correction of these errors is individually or in aggregate material to the consolidated financial statements for the three and nine months ended September 30, 2020 or to any prior period consolidated financial statements.
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. On an ongoing basis, management reviews these estimates and assumptions. Changes in facts and circumstances may alter such estimates and actual results could differ from those estimates. In the Company’s opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of its financial position, results of operations and cash flows for the interim periods presented.
Net Income (Loss) per Share	Net Income (Loss) per Share The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net income (loss) $ 33,004 $ (49,439 ) $ (130,657 ) $ 21,153 Weighted average shares used to compute net income (loss) per share: Basic 90,558 87,007 89,414 86,390 Dilutive effect of potential common shares 3,120 — — 5,605 Diluted 93,678 87,007 89,414 91,995 Net income (loss) per share: Basic $ 0.36 $ (0.57 ) $ (1.46 ) $ 0.24 Diluted $ 0.35 $ (0.57 ) $ (1.46 ) $ 0.23 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. During the nine months ended September 30, 2020, and the three months ended September 30, 2019, the Company reported a net loss. Therefore, dilutive common shares are not assumed to have been issued since their effect is anti-dilutive. Diluted weighted average shares excluded potential common shares related to stock options, restricted stock units and shares to be purchased under the employee stock purchase plan totaling 4.2 million and 9.2 million, respectively, for the three months ended September 30, 2020 and 2019, and totaling 8.9 million and 3.6 million, respectively, for the nine months ended September 30, 2020 and 2019, 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 COVID-19 and the related shelter-in-place, stay-at-home and other similar governmental orders issued in response to the COVID-19 pandemic. Starting in the first quarter of 2020, the Company experienced slower enrollment in its clinical trials due to the interruption caused by COVID-19 in the worldwide healthcare system. The future impact of the COVID-19 pandemic on the Company’s business is highly uncertain and difficult to predict. The COVID-19 pandemic may continue to affect enrollment in and initiation of the Company’s clinical trials, and could affect the Company’s supply chain if further social distancing and other business restrictions are put in place by various government entities, particularly in China and the U.S. COVID-19 may affect the health of the Company’s employees limiting the Company’s productivity. The COVID-19 pandemic may also impact the market for the Company’s products and product candidates in the future, affecting sales of the Company’s products. Such possible risks and uncertain impacts from the COVID-19 pandemic could have a material adverse effect on the Company’s drug development, commercialization revenues, and other portions of its business, and in particular, could impact the Company’s assumptions of accounts receivable collectability, fair value measurements of investments, liquidity, and development costs. The extent of the pandemic’s effect on the Company’s operational and financial performance will depend in large part on future developments, particularly with respect to the scope and severity of the pandemic, governmental restrictions put in place to fight the pandemic, and the development of vaccines and treatments for COVID-19. Due to the inherent uncertainty of the unprecedented and rapidly evolving situation, the Company is unable to estimate the likely impact of the COVID-19 pandemic on its future operations.
Recently Issued and Adopted Accounting Guidance	Recently Issued and Adopted Accounting Guidance In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Codification Improvements to Topic 326, Financial Instruments-Credit Losses ,
Recently Issued Accounting Guidance Not Yet Adopted	Recently Issued Accounting Guidance Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes 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 2019 Form 10-K, except for the following: Variable Interest Entity Under the Accounting Standards Codification (“ASC”) 810, Consolidation Foreign currency translation Prior to April 1, 2020, the functional currency of the Company’s subsidiary, FibroGen (China) Medical Technology Development Co., Ltd. (“FibroGen Beijing”), was the U.S. dollar. Accordingly, monetary assets and liabilities of FibroGen Beijing in the currencies other than USD were remeasured using exchange rates in effect at the end of the period. Revenues and costs in its local currency, Renminbi Yuan (“CNY”), were remeasured using average exchange rates for the period, except for costs related to those balance sheet items that were remeasured using historical exchange rates. The resulting remeasurement gains and losses were included within interest income and other, net in the consolidated statements of operations as incurred. On April 1, 2020, FibroGen Beijing adopted CNY as its functional currency based on reassessment of the primary economic operational environment of FibroGen Beijing that is mainly associated with its growing manufacturing and product sales activities conducted in CNY. As such, monetary assets and liabilities of FibroGen Beijing in currencies other than CNY are remeasured using exchange rates in effect at the end of the period. The assets and liabilities are translated to U.S. dollars at exchange rates in effect at the balance sheet date. All income statement accounts are translated at monthly average exchange rates. Resulting foreign currency translation adjustments are recorded directly in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity. This change in FibroGen Beijing’s functional currency was accounted for prospectively from April 1, 2020, and the prior condensed consolidated financial statements were not restated. The related currency translation adjustment was $1.3 million at April 1, 2020, upon adoption. Trade accounts receivable The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts. The Company makes estimates of expected credit losses for the allowance for doubtful accounts by considering factors such as historical experience, credit quality, the age of the accounts receivable balances, current economic and regulatory conditions that may affect a customer’s ability to pay, and estimates of expected future losses. The Company’s bad debt expense for the three and nine months ended September 30, 2020 and the allowance for doubtful accounts as of September 30, 2020 were immaterial. Credit losses – Available-for-sale debt securities The Company periodically assesses its available-for-sale investments for other-than-temporary impairment. For debt securities in an unrealized loss position, the Company first considers its intent to sell, or whether it is more likely than not that the Company will be required to sell the debt securities before recovery of their amortized cost basis. If either of these criteria are met, the amortized cost basis of such debt securities is written down to fair value through interest and other, net. For debt securities in an unrealized loss position that do not meet the aforementioned criteria, the Company assesses whether the decline in the fair value of such debt securities has resulted from credit losses or other factors. The Company considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and any adverse conditions specifically related to the securities, among other factors. If this assessment indicates that a credit loss may exist, the Company then compares the present value of cash flows expected to be collected from such securities to their amortized cost basis. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded through interest and other, net, limited by the amount that the fair value is less than the amortized cost basis. Any additional impairment not recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are recorded as provision for, or reversal of, credit loss expense. Losses are charged against the allowance when the Company believes that an available-for-sale security is confirmed uncollectable or when either of the criteria regarding intent or requirement to sell is met. Product revenue, net The Company sells roxadustat in China through a number of pharmaceutical distributors located in China. 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 a general 60-day payment term. As such, product revenue is not adjusted for the effects of a significant financing component. Product rev enue is recorded at the net sales prices (transaction price) which includes the following estimates of variable consideration: • Price adjustment: In December 2019, China’s National Healthcare Security Administration released price guidance for roxadustat under the National Reimbursement Drug List (“NRDL”), effective January 1, 2020. Any channel inventories as of January 1, 2020 that had not been sold to hospitals by distributors, or to patients by hospitals, were eligible for a price adjustment under the price protection. The price adjustment is calculated based on estimated channel inventory levels at January 1, 2020. If price guidance changes in the future, the price adjustment will be calculated in the same manner; • Contractual sales rebate : The contractual sales rebate is calculated based on the stated percentage of gross sales by each distributor in the distribution agreement entered between FibroGen and each distributor. The contractual sales rebate is recorded as a reduction to revenue at the point of sale to the distributor; • Key account hospital sales rebate : An additional sales rebate is provided to a distributor for product sold to key account hospitals as a percentage of gross sales made by the distributor to eligible hospitals. This additional rebate is recorded as a reduction to revenue at the point of sale to the distributor; • Transfer fee discount : The transfer fee discount is offered to a distributor who has its downstream distributors supply to eligible hospitals. This discount is calculated based on a percentage of gross sales made to the downstream distributors, and recorded as a reduction to revenue as incurred; • 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. The Company, at its sole discretion, decides whether to accept such return request; and • Non-key account hospital listing award: A one-time fixed-amount award is offered to a distributor who successfully lists the product with an eligible hospital, and who meets certain requirements. The Company considers this particular award to be an upfront payment to a customer within the definitions of ASC 606. The non-key account hospital listing award is capitalized when the distributor meets eligibility requirements, and amortized as reduction to product revenue over future sales orders made by the distributor until exhausted. 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. The distributor’s legal right of offset is calculated at the individual distributor level.
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 aggregate amount of consideration received through September 30, 2020 totals $90.1 million. The Japan Agreement also provides for tiered payments based on net sales of roxadustat in the low 20% range after commercial launch. 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 roxadustat in the low 20% range. The aggregate amount of consideration received through September 30, 2020 totals $540.0 million. During the second quarter of 2019, the Company received positive topline results from analyses of pooled major adverse cardiac event (“MACE”) and MACE plus hospitalized unstable angina and hospitalized congestive heart failure (“MACE+”) data from its Phase 3 trials evaluating roxadustat as a treatment for dialysis and non-dialysis CKD patients, enabling Astellas to prepare for an MAA submission to the EMA, following the Company’s NDA submission to the FDA. These milestones became probable of being achieved in the second quarter of 2019, and the total consideration of $130.0 million associated with these milestones was included in the transaction price and allocated to performance obligations under the Europe Agreement in the second quarter of 2019, of which $128.8 million was recognized as revenue during 2019, and $0.6 million was recognized as revenue during the nine months ended September 30, 2020, from performance obligations satisfied or partially satisfied. According to the Europe Agreement, these milestone payments were billed to Astellas upon the submission of an MAA in the second quarter of 2020 and the total $130.0 million was received during the same quarter. 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, $15.0 million of which was received in 2015 as a result of the finalization of its two audited pre-clinical carcinogenicity study reports, and the remaining $50.0 million was received in April 2020 as a result of the NDA submission milestone, (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 through September 30, 2020 totals $439.0 million. As mentioned above, during the second quarter of 2019, the Company received positive topline results from analyses of pooled MACE and MACE+ data from its Phase 3 trials for roxadustat, enabling the Company’s NDA submission to the FDA. The regulatory milestone payment associated with this NDA submission became probable of being achieved in the second quarter of 2019. Accordingly, the consideration of $50.0 million associated with this milestone was included in the transaction price and allocated to performance obligations under the U.S./ RoW Agreement in the second quarter of 2019, of which $42.4 million was recognized as revenue during 2019, and $0.6 million was recognized as revenue during the nine months ended September 30, 2020, from performance obligations satisfied or partially satisfied. The Company submitted such NDA in December 2019, which was accepted by the FDA for review in February 2020. According to the U.S/RoW Agreement, this milestone payment is billable to AstraZeneca when the NDA is accepted by the FDA. Therefore, this $50.0 million was billed during the first quarter of 2020, the payment of which was fully received in April 2020. AstraZeneca and Astellas approved the development of roxadustat for the treatment of chemotherapy-induced anemia in December 2018 and January 2019, respectively. Costs associated with the development of this indication are expected to be shared 50/50 between AstraZeneca and Astellas. In addition, in December 2018, anemia of chronic inflammation and multiple myeloma was approved for development by AstraZeneca and is expected to be fully funded by them. For revenue recognition purposes, the Company concluded that the addition of these new indications represents a modification to the collaboration agreements and will be accounted for separately, meaning the development costs associated with the new indications are distinct from the original development costs. The development service period for roxadustat for the treatment of chemotherapy-induced anemia, anemia of chronic inflammation and multiple myeloma under the AstraZeneca agreements is estimated to continue through the end of 2024, to allow for development of these additional indications. China Agreement Effective July 30, 2013, the Company (through its subsidiaries affiliated with China) entered into the 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 was 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. The aggregate amount of such consideration received for milestone and upfront payments through September 30, 2020 totals $77.2 million. In December 2019, roxadustat was included on the updated NRDL released by China’s National Healthcare Security Administration for the treatment of anemia in CKD, covering patients who are non-dialysis dependent as well as those who are dialysis-dependent. The inclusion on the NRDL triggered a total of $22.0 million of milestones payable to the Company by AstraZeneca. Accordingly, the total consideration of $22.0 million associated with these milestones was included in the transaction price and allocated to performance obligations under the China Agreement during the fourth quarter of 2019. This milestone payment was received during the first quarter of 2020. China Amendment On July 8, 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 will perform roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. See Note 2, Acquisition and Variable Interest Entity In accordance with the China Amendment, the Company is currently in the interim period. Under the China Amendment, the interim period is defined as the period from April 1, 2020 to the time when Falikang is fully operational, expected in early 2021. During the interim period, FibroGen will continue to sell product directly to the distributors, who remain as the Company’s customers. Under the China Amendment, the calculation for profit or loss share has changed related to sales of roxadustat in China 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. Once Falikang is fully operational, AstraZeneca will bill the co-promotion expenses to Falikang, rather than FibroGen Beijing. In addition, FibroGen Beijing will manufacture and supply commercial product to Falikang based on an agreed upon transfer price. Development costs will continue to be shared 50/50 between the Parties. As a result, the interim period primarily includes the following activities : • Co-promotion expenses: The China Amendment revised the payment arrangements and calculation of the historical unpaid co-promotion expenses to AstraZeneca for its sales and marketing efforts associated with the commercial sales for roxadustat in China since the product launch. Under the previous China Agreement, payment of these historical co-promotion expenses was subject to certain profitability and cash flow thresholds. No amount of the historical co-promotion costs had been paid prior to the China Amendment as these thresholds had not yet been met. Under the China Amendment, a portion of the historical unpaid co-promotion expenses was adjusted to reduce the amount owed by FibroGen Beijing and the current period co-promotion expenses are capped at a percentage of net roxadustat sales in China. As a result, in the third quarter of 2020, the Company reversed approximately $84.4 million of previously accrued co-promotion expenses payable, which was recorded as a reduction to selling, general and administrative expenses, where these expenses were initially recorded during the periods from the initiation of commercial activities in the first quarter of 2019 to the second quarter of 2020. The co-promotion expenses for the three and nine months ended September 30, 2020, capped at a percentage of net roxadustat sales in China, were $8.8 million and $14.8 million, respectively, included in the selling, general and administrative expenses. After this adjustment, as of September 30, 2020, $14.8 million of the recalculated accrued co-promotion expenses was recorded as a current liability, as it is anticipated to be paid within the next 12 months ; and $26.3 million of the recalculated accrued co-promotion expenses remained in the long-term liabilities, as it is not anticipated to be paid within the next 12 months . • Profit share: Profit/loss share between FibroGen China and AstraZeneca is based on a calculation of the current period net roxadustat sales in China and deductible expenses pursuant to the China Agreement. Based on the calculation, a profit was achieved during the third quarter of 2020. As a result, the Company recorded a profit share liability of $2.0 million to AstraZeneca in the three months ended September 30, 2020 in the condensed consolidated statement of operations.
Product Revenue	Product Revenue, Net Product revenue from roxadustat commercial sales 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. Product revenue, net was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Gross revenue $ 27,900 $ 622 $ 53,105 $ 622 Non-key account hospital listing award (2,930 ) — (5,495 ) — Contractual sales rebate (1,966 ) (43 ) (3,714 ) (43 ) Other discounts and rebates (313 ) — (512 ) — Sales return (8 ) — (53 ) — Product revenue, net $ 22,683 $ 579 $ 43,331 $ 579 In the second quarter of 2020, the Company amended the agreement with its pharmaceutical distributors, which triggered accounting modifications particularly related to non-key account hospital listing award. For the three and nine months ended September 30, 2020, the non-key account hospital listing award was $2.9 million and $5.5 million, respectively, which was recorded as a reduction to the revenue and calculated based on eligible non-key account hospital listing to date achieved by each distributor with certain requirements met during the period. For the three and nine months ended September 30, 2020, the contractual sales rebate was $2.0 million and $3.7 million, respectively, which were calculated based on the stated percentage of gross sales by each distributor in the distribution agreement entered between FibroGen and each distributor. All other rebates and discounts, including sales return allowance were immaterial for the periods presented. 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 distributor’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. The distributor’s legal right of 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, 2019 Additions Deduction Currency Translation and Other Gross Contract Liabilities Balance Balance Presented Net Against Accounts Receivable Balance at September 30, 2020 Contract liabilities $ (1,102 ) $ (10,623 ) $ 450 $ (117 ) $ (11,392 ) $ 9,759 $ (1,633 ) As of September 30, 2020, the total rebates and discounts as reductions to gross accounts receivable was $9.8 million, and the total contract liabilities was $1.6 million, which was included in accrued and other current liabilities in the condensed consolidated balance sheet. The reductions to gross accounts receivable, including the above-mentioned contra-accounts receivable items related to product revenue, consisted of the following (in thousands): September 30, 2020 December 31, 2019 Price adjustment $ 529 $ 936 Contractual sales rebate 3,479 148 Non-key account hospital listing award 5,238 — Other discounts and rebates 513 18 Sales return 53 — Provision for credit loss 102 — Total reductions to gross accounts receivable $ 9,914 $ 1,102
Drug Product Revenue	Drug Product Revenue Drug product revenue was as follows (in thousands): Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Astellas $ (3,957 ) $ 4,281 AstraZeneca 4,643 4,643 Drug product revenue $ 686 $ 8,924 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 deliver to Astellas roxadustat active pharmaceutical ingredient (“API”) for the roxadustat commercial launch in Japan. Related to the API shipments in 2018 under the Japan Amendment, during the three months ended September 30, 2020, the Company recorded a $4.0 million reduction to drug product revenue, related to a change in estimated variable consideration. Specifically, the change in estimated variable consideration was based on the API held by Astellas at March 31, 2020 adjusted to reflect the updated listed price for roxadustat issued by the Japanese Ministry of Health, Labour and Welfare and changes in the estimated bulk product strength mix intended to be manufactured by Astellas, estimated cost to convert the API to bulk product tablets, and estimated yield from the manufacture of bulk product tablets, among others. During the three months ended June 30, 2020, the Company fulfilled delivery obligations under the term of the Japan Amendment, and recognized the related drug product revenue of $8.2 million in the same period. The amount represents variable consideration and was estimated based on the quantity of product shipped, actual listed price for roxadustat issued by the Japanese Ministry of Health, Labour and Welfare and possible future changes to the listed price, adjusted for 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. Under the U.S./RoW Agreement, FibroGen would manufacture and deliver to AstraZeneca roxadustat bulk drug product in support of commercial supplies. The Company delivered bulk drug product to AstraZeneca as pre-commercial supply for process validation purposes in the three months ended March 31, 2020, June 30, 2020 and September 30, 2020, respectively. The related drug product revenue of $4.6 million was recognized in the three months ended September 30, 2020. The drug product revenue amount represents variable consideration and was estimated based on the quantity of product shipped and an estimated price. The amount of variable consideration that is included in the transaction price may be constrained, and is included in the drug product revenue 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. Actual amounts of consideration ultimately received in the future may differ from the Company’s estimates, for which the Company will adjust these estimates and affect the drug product revenue in the period such variances become known.
Other Revenues	Other Revenues Other revenues consist primarily of collagen material sold for research purposes. Other revenues were immaterial for all periods presented.
Deferred Revenue	Deferred Revenue Deferred revenue represents amounts billed, or in certain cases, yet to be billed to the Company’s collaboration partners for which the related revenues have not been recognized because one or more of the revenue recognition criteria have not been met. The current portion of deferred revenue represents the amount to be recognized within one year from the balance sheet date based on the estimated performance period of the underlying performance obligations. The long-term portion of deferred revenue represents amounts to be recognized after one year through the end of the non-contingent performance period of the underlying performance obligations. Deferred revenue includes amounts allocated to the China unit of accounting under the AstraZeneca arrangement as revenue recognition associated with this unit of accounting is tied to the commercial sales of the products within China. As of September 30, 2020, approximately $3.2 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.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Reconciliation of Basic and Diluted Net Income (Loss) Per Share Calculation	The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net income (loss) $ 33,004 $ (49,439 ) $ (130,657 ) $ 21,153 Weighted average shares used to compute net income (loss) per share: Basic 90,558 87,007 89,414 86,390 Dilutive effect of potential common shares 3,120 — — 5,605 Diluted 93,678 87,007 89,414 91,995 Net income (loss) per share: Basic $ 0.36 $ (0.57 ) $ (1.46 ) $ 0.24 Diluted $ 0.35 $ (0.57 ) $ (1.46 ) $ 0.23

Collaboration Agreements and _2

Collaboration Agreements and Revenues (Tables)	9 Months Ended
	Sep. 30, 2020
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue	Product revenue, net was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Gross revenue $ 27,900 $ 622 $ 53,105 $ 622 Non-key account hospital listing award (2,930 ) — (5,495 ) — Contractual sales rebate (1,966 ) (43 ) (3,714 ) (43 ) Other discounts and rebates (313 ) — (512 ) — Sales return (8 ) — (53 ) — Product revenue, net $ 22,683 $ 579 $ 43,331 $ 579
Roll-forward of Contract Liabilities	The following table includes a roll-forward of the contract liabilities (in thousands): Balance at December 31, 2019 Additions Deduction Currency Translation and Other Gross Contract Liabilities Balance Balance Presented Net Against Accounts Receivable Balance at September 30, 2020 Contract liabilities $ (1,102 ) $ (10,623 ) $ 450 $ (117 ) $ (11,392 ) $ 9,759 $ (1,633 )
Summary of Contra-Accounts Receivable Items Related to Product Revenue	The reductions to gross accounts receivable, including the above-mentioned contra-accounts receivable items related to product revenue, consisted of the following (in thousands): September 30, 2020 December 31, 2019 Price adjustment $ 529 $ 936 Contractual sales rebate 3,479 148 Non-key account hospital listing award 5,238 — Other discounts and rebates 513 18 Sales return 53 — Provision for credit loss 102 — Total reductions to gross accounts receivable $ 9,914 $ 1,102
Schedule of Drug Product Revenue	Drug product revenue was as follows (in thousands): Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Astellas $ (3,957 ) $ 4,281 AstraZeneca 4,643 4,643 Drug product revenue $ 686 $ 8,924
Japan [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Japan Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Performance Obligation 2020 2019 2020 2019 Japan License revenue $ — $ 11,935 $ — $ 11,935 Development revenue $ 86 $ 537 $ 413 $ 1,151
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue	The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Japan Agreement, along with any associated deferred revenue as follows (in thousands): Japan Agreement Cumulative Revenue Through September 30, 2020 Deferred Revenue at September 30, 2020 Total Consideration Through September 30, 2020 License $ 86,024 $ — $ 86,024 Development revenue 15,543 164 15,707 Total license and development revenue $ 101,567 $ 164 $ 101,731
Europe [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Performance Obligation 2020 2019 2020 2019 Europe License revenue $ — $ — $ — $ 117,470 Development revenue $ 4,651 $ 2,996 $ 13,827 $ 24,463
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue	The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the Europe Agreement, along with any associated deferred revenue as follows (in thousands): Europe Agreement Cumulative Revenue Through September 30, 2020 Deferred Revenue at September 30, 2020 Total Consideration Through September 30, 2020 License $ 487,951 $ — $ 487,951 Development revenue 244,834 2,096 246,930 Total license and development revenue $ 732,785 $ 2,096 $ 734,881
U.S./RoW and China [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the U.S./RoW and China Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Performance Obligation 2020 2019 2020 2019 U.S. / RoW and China License revenue $ — $ — $ — $ 33,112 Development revenue 15,220 17,106 43,525 59,872 China performance obligation $ 706 $ 19 $ 1,300 $ 19
Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue	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, along with any associated deferred revenue as follows (in thousands): U.S. / RoW and China Agreements Cumulative Revenue Through September 30, 2020 Deferred Revenue at September 30, 2020 Total Consideration Through September 30, 2020 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 536,792 2,435 539,227 China performance obligation 1,390 141,171 142,561 Total license and development revenue $ 880,026 $ 143,606 $ 1,023,632

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Values of Financial Assets Measured on Recurring Basis	The fair values of the Company’s financial assets that are measured on a recurring basis are as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 125,388 $ — $ — $ 125,388 Equity investments 247 — — 247 Money market funds 451,917 — — 451,917 Certificate of deposit — 30,010 — 30,010 Total $ 577,552 $ 30,010 $ — $ 607,562 December 31, 2019 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 347,383 $ 80,123 $ — $ 427,506 Bond and mutual funds 10,816 — — 10,816 Equity investments 255 — — 255 Money market funds 85,551 — — 85,551 Certificate of deposit — 30,032 — 30,032 Total $ 444,005 $ 110,155 $ — $ 554,160
Fair Values of Financial Liabilities Carried at Historical Cost	The fair values of the Company’s financial liabilities that are carried at historical cost are as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,242 $ 1,242 December 31, 2019 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,544 $ 1,544

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
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 September 30, 2020 December 31, 2019 Assets Finance: Right-of-use assets - cost $ 50,220 $ 49,909 Accumulated amortization (18,192 ) (10,307 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 32,028 39,602 Operating: Right-of-use assets - cost 2,796 2,736 Accumulated amortization (1,554 ) (805 ) Operating lease right-of-use assets, net Other assets 1,242 1,931 Total lease assets $ 33,270 $ 41,533 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 12,311 $ 12,351 Operating lease liabilities Accrued and other current liabilities 770 983 Non-current: Finance lease liabilities Finance lease liabilities, non-current 28,514 37,610 Operating lease liabilities Other long-term liabilities 472 942 Total lease liabilities $ 42,067 $ 51,886
Components of Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Statement of Operations Line Item 2020 2019 2020 2019 Finance lease cost: Amortization of right-of-use assets Cost of goods sold; Research and development; Selling, general and administrative expenses $ 2,639 $ 2,580 $ 7,886 $ 7,720 Interest on lease liabilities Interest expense 462 578 1,511 1,826 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 304 290 868 579 Sublease income Selling, general and administrative expenses (301 ) (310 ) (899 ) (1,135 ) Total lease cost $ 3,104 $ 3,138 $ 9,366 $ 8,990
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases were as follows (in thousands): Nine Months Ended September 30, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 812 $ 540 Operating cash flows from finance leases 1,468 1,640 Financing cash flows from finance leases 9,254 8,810 Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 434 49,784 Operating leases $ 55 $ 2,723
Schedule of Lease Term and Discount Rate	Lease term and discount rate were as follows: September 30, 2020 December 31, 2019 Weighted-average remaining lease term (years): Finance leases 3.1 3.6 Operating leases 1.6 2.1 Weighted-average discount rate: Finance leases 4.39 % 4.42 % Operating leases 4.73 % 4.75 %
Schedule of Maturities of Finance and Operating Leases Liabilities	Maturities of lease liabilities as of September 30, 2020 are as follows (in thousands): Year Ending Finance Leases Operating Leases 2020 (Remaining three month period) $ 3,542 $ 245 2021 13,683 714 2022 13,883 329 2023 12,524 — Total future lease payments 43,632 1,288 Less: Interest (2,807 ) (46 ) Present value of lease liabilities $ 40,825 $ 1,242

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): September 30, 2020 December 31, 2019 Cash $ 80,551 $ 40,715 Money market funds 451,917 85,551 Total cash and cash equivalents $ 532,468 $ 126,266
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, marketable equity investments, term deposit and certificate of deposit. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s investments by major investments type are summarized in the tables below (in thousands): September 30, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 124,993 $ 395 $ — $ 125,388 Certificates of deposit 30,000 10 — 30,010 Equity investments 125 122 — 247 Total investments $ 155,118 $ 527 $ — $ 155,645 December 31, 2019 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 426,995 $ 536 $ (25 ) $ 427,506 Certificates of deposit 30,000 32 — 30,032 Bond and mutual funds 10,730 86 — 10,816 Equity investments 125 130 — 255 Total investments $ 467,850 $ 784 $ (25 ) $ 468,609
Schedule of Inventory	Inventories consisted of the following (in thousands): September 30, 2020 December 31, 2019 Raw materials $ 1,152 $ 325 Work-in-progress 5,616 2,264 Finished goods 5,034 4,298 Total inventories $ 11,803 $ 6,887
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): September 30, 2020 December 31, 2019 Unbilled contract assets $ — $ 180,000 Deferred revenues from associated contracts — (54,790 ) Net unbilled contract assets — 125,210 Prepaid assets 5,549 6,464 Other current assets 6,014 1,717 Total prepaid expenses and other current assets $ 11,563 $ 133,391
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): September 30, 2020 December 31, 2019 Leasehold improvements $ 101,162 $ 101,548 Laboratory equipment 17,890 17,329 Machinery 8,012 8,217 Computer equipment 9,124 8,399 Furniture and fixtures 6,110 5,822 Construction in progress 1,506 1,792 Total property and equipment $ 143,804 $ 143,107 Less: accumulated depreciation (107,651 ) (100,364 ) Property and equipment, net $ 36,153 $ 42,743
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): September 30, 2020 December 31, 2019 Preclinical and clinical trial accruals $ 29,396 $ 16,279 API product price adjustment 3,957 36,324 Payroll and related accruals 19,606 19,784 Accrued co-promotion expenses - current 14,836 — Property taxes and other 6,057 2,044 Professional services 7,384 4,842 Other 9,336 4,543 Total accrued and other current liabilities $ 90,572 $ 83,816
Schedule of Other Long-term Liabilities	Other long-term liabilities consisted of the following (in thousands): September 30, 2020 December 31, 2019 Accrued long-term co-promotion expenses $ 26,344 $ 53,071 Other long-term tax liabilities 8,637 8,913 Operating lease liabilities, non-current 472 942 Other 2,186 1,340 Total other long-term liabilities $ 37,639 $ 64,266

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
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 September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Research and development $ 11,236 $ 10,185 $ 32,653 $ 30,214 Selling, general and administrative 6,655 4,608 19,798 18,651 Total stock-based compensation expense $ 17,891 $ 14,793 $ 52,451 $ 48,865
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 September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Stock Options Expected term (in years) 5.6 5.3 5.7 5.3 Expected volatility 59.0 % 67.8 % 67.7 % 67.9 % Risk-free interest rate 0.3 % 1.7 % 0.8 % 2.4 % Expected dividend yield — — — — Weighted average estimated fair value $ 22.48 $ 25.17 $ 18.11 $ 32.44 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Expected volatility 50.4 - 77.1 % 48.1 - 62.1 % 49.5 - 77.1 % 48.1 - 62.1 % Risk-free interest rate 0.2 - 2.9 % 1.6 - 2.9 % 0.2 - 2.9 % 1.3 - 2.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 17.00 $ 19.27 $ 17.74 $ 19.53

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Detail) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)shares	Sep. 30, 2019shares	Sep. 30, 2020Segmentshares	Sep. 30, 2019shares	Apr. 01, 2020USD ($)
Accounting Policies [Abstract]
Number of operating segment | Segment			1
Immaterial error correction	During the third quarter of 2020, the Company recorded out-of-period adjustments that resulted in a net decrease in revenue of $2.1 million. The Company does not believe the correction of these errors is individually or in aggregate material to the consolidated financial statements for the three and nine months ended September 30, 2020 or to any prior period consolidated financial statements.
Decrease in revenue due to out of period adjustments	$ 2.1
Anti-dilutive shares outstanding | shares	4.2	9.2	8.9	3.6
Currency translation adjustment					$ 1.3
Description of payment term			The period between the transfer of control of the promised goods and when the Company receives payment is based on a general 60-day payment term.
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.

Significant Accounting Polici_5

Significant Accounting Policies - Summary of Reconciliation of Basic and Diluted Net Income (Loss) Per Share Calculation (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income (loss)	$ 33,004	$ (49,439)	$ (130,657)	$ 21,153
Weighted average number of common shares used to calculate net income (loss) per share:
Basic	90,558	87,007	89,414	86,390
Dilutive effect of potential common shares	3,120	0	0	5,605
Diluted	93,678	87,007	89,414	91,995
Net income (loss) per share:
Basic	$ 0.36	$ (0.57)	$ (1.46)	$ 0.24
Diluted	$ 0.35	$ (0.57)	$ (1.46)	$ 0.23

Acquisition and Variable Inte_2

Acquisition and Variable Interest Entity - Additional Information (Detail) $ in Thousands, ¥ in Millions	Sep. 15, 2020USD ($)	Sep. 15, 2020CNY (¥)	Oct. 31, 2020CNY (¥)	Jul. 31, 2020USD ($)	Jul. 31, 2020CNY (¥)	Sep. 30, 2020USD ($)	Sep. 30, 2020CNY (¥)	Sep. 30, 2019USD ($)	Sep. 30, 2020CNY (¥)
Acquisition And Variable Interest Entity [Line Items]
Cash consideration | $						$ 2,145		$ 0
Cash consideration for exchange of outstanding shares							¥ 7.3
Subsequent Event [Member]
Acquisition And Variable Interest Entity [Line Items]
Cash consideration received			¥ 7.3
AstraZeneca AB [Member]
Acquisition And Variable Interest Entity [Line Items]
Acquisition costs							¥ 2.5
AstraZeneca AB [Member] | Prepaid Expenses and Other Current Assets [Member]
Acquisition And Variable Interest Entity [Line Items]
Receivable						$ 1,400			¥ 9.8
Beijing Falikang Pharmaceutical Co. Ltd [Member]
Acquisition And Variable Interest Entity [Line Items]
Percentage of outstanding shares owned						51.10%	51.10%
Investment						$ 1,500			¥ 10.2
Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] | FibroGen Beijing [Member]
Acquisition And Variable Interest Entity [Line Items]
Percentage of outstanding shares acquired					100.00%
Cash consideration				$ 2,100	¥ 15
Transaction costs					5
Acquisition costs				400	¥ 2.5
Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] | FibroGen Beijing [Member] | Beijing Falikang Pharmaceutical Co. Ltd [Member] | AstraZeneca AB [Member]
Acquisition And Variable Interest Entity [Line Items]
Percentage of outstanding shares sold in exchange for cash consideration	48.90%	48.90%
Cash consideration for exchange of outstanding shares	$ 1,000	¥ 7.3
Percentage of outstanding shares owned	51.10%	51.10%
Beijing Kangda Yongfu Pharmaceutical Co., LTD [Member] | FibroGen Beijing [Member] | Acquired License [Member]
Acquisition And Variable Interest Entity [Line Items]
Entire purchase price | $				$ 2,500

Collaboration Agreements and _3

Collaboration Agreements and Revenues - Astellas Agreements - Additional Information (Detail) - Astellas Agreement [Member] - USD ($) $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended	35 Months Ended	45 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Jun. 30, 2020	Sep. 30, 2020	Feb. 28, 2009	Feb. 28, 2009	Dec. 31, 2019	Jun. 30, 2019
Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received						$ 40.1
Potential milestone payments		$ 132.5
Commercial sales milestone		15
Additional consideration based on net sales description				low 20% range
Aggregate consideration received				$ 90.1
Japan [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		22.5
Japan [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		$ 95
Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received					$ 320
Additional consideration based on net sales description				low 20% range
Aggregate consideration received				$ 540
Development and regulatory approval milestones	$ 425
Percentage of joint development costs committed to fund	50.00%
Transaction price and allocated to performance obligations								$ 130
Revenue during period from performance obligations				$ 0.6			$ 128.8
Milestone payment received			$ 130
Europe [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 90
Europe [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 335

Collaboration Agreements and _4

Collaboration Agreements and Revenues - AstraZeneca Agreements - Additional Information 1 (Detail) - USD ($)	Jul. 30, 2013	Apr. 30, 2020	Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2015	Mar. 31, 2020	Jun. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled contract asset			$ 180,000,000	$ 0	$ 0
Accrued long-term co-promotion expenses			53,071,000	26,344,000	26,344,000
Accrued long term co promotion liability current				14,800,000	14,800,000
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price and allocated to performance obligations								$ 50,000,000
Revenue during period from performance obligations			42,400,000	600,000	600,000
Unbilled contract asset							$ 50,000,000
Historical co-promotion costs				0	0
Accrued long term co promotion liability current				14,800,000	14,800,000
AstraZeneca Agreements [Member] | Selling, General and Administrative Expenses [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reversal of accrued co-promotion expenses				84,400,000
Co-promotion expenses				8,800,000	14,800,000
AstraZeneca Agreements [Member] | Other Noncurrent Liabilities
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accrued long-term co-promotion expenses				26,300,000	26,300,000
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent, non-refundable and time-based payments	$ 374,000,000
Potential milestone payments	875,000,000
Commercial sales milestone	325,000,000
Aggregate consideration received				439,000,000	$ 439,000,000
Unbilled contract asset			50,000,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	65,000,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	325,000,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Deferred Approval Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	160,000,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receipt of development milestone payment						$ 15,000,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | NDA Submission Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receipt of development milestone payment		$ 50,000,000
AstraZeneca Agreements [Member] | China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	348,500,000		22,000,000
Transaction price and allocated to performance obligations			$ 22,000,000
Estimated joint development extended service period					2024
Proceeds from upfront, non-contingent and non-refundable payments	28,200,000
Commercial sales and other events milestone	187,500,000
Aggregate consideration received for milestone and upfront payments				77,200,000	$ 77,200,000
Changes in revenue due to prior period adjustment of performance obligations				$ (2,000,000)
AstraZeneca Agreements [Member] | China [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	15,000,000
AstraZeneca Agreements [Member] | China [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 146,000,000

Collaboration Agreements and _5

Collaboration Agreements and Revenues - Summary of Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 44,032	$ 33,174	$ 111,320	$ 248,603
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	11,935	0	162,517
Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	20,663	20,660	59,065	85,507
Astellas Agreement [Member] | License Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	11,935	0	11,935
Astellas Agreement [Member] | License Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	117,470
Astellas Agreement [Member] | Development Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	86	537	413	1,151
Astellas Agreement [Member] | Development Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	4,651	2,996	13,827	24,463
AstraZeneca Agreements [Member] | China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	706	19	1,300	19
AstraZeneca Agreements [Member] | License Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	33,112
AstraZeneca Agreements [Member] | Development Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 15,220	$ 17,106	$ 43,525	$ 59,872

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	Sep. 30, 2020	Dec. 31, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	$ 0	$ 54,790
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	101,567
Deferred Revenue	164
Total Consideration	101,731
Astellas Agreement [Member] | Japan [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	15,543
Deferred Revenue	164
Total Consideration	15,707
Astellas Agreement [Member] | Japan [Member] | License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	86,024
Deferred Revenue	0
Total Consideration	86,024
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	732,785
Deferred Revenue	2,096
Total Consideration	734,881
Astellas Agreement [Member] | Europe [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	244,834
Deferred Revenue	2,096
Total Consideration	246,930
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] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	880,026
Deferred Revenue	143,606
Total Consideration	1,023,632
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	536,792
Deferred Revenue	2,435
Total Consideration	539,227
AstraZeneca Agreements [Member] | U.S./RoW and China [Member] | China performance obligation [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	1,390
Deferred Revenue	141,171
Total Consideration	$ 142,561

Collaboration Agreements and _7

Collaboration Agreements and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail)	3 Months Ended
	Sep. 30, 2020USD ($)
Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Remainder of transaction price, variable consideration from estimated future co-development billing	$ 0
Japan [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	100,000
Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Remainder of transaction price, variable consideration from estimated future co-development billing	31,500,000
Europe [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	1,300,000
U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Remainder of transaction price, variable consideration from estimated future co-development billing	52,300,000
U.S./RoW and China [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	(600,000)
China [Member] | AstraZeneca Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	$ (2,000,000)

Collaboration Agreements and _8

Collaboration Agreements and Revenues - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 44,032	$ 33,174	$ 111,320	$ 248,603
Non-key Account Hospital Listing Award [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2,900		5,500
Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2,000		3,700
Product [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	27,900	622	53,105	622
Total revenue	22,683	579	43,331	579
Product [Member] | Non-key Account Hospital Listing Award [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(2,930)	0	(5,495)	0
Product [Member] | Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(1,966)	(43)	(3,714)	(43)
Product [Member] | Other Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(313)	0	(512)	0
Product [Member] | Sales Return [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ (8)	$ 0	$ (53)	$ 0

Collaboration Agreements and _9

Collaboration Agreements and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 44,032	$ 33,174	$ 111,320	$ 248,603
Non-key Account Hospital Listing Award [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	2,900		5,500
Contractual Sales Rebate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 2,000		3,700
Rebates and Discounts [Member] | Gross Accounts Receivable [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			9,800
Rebates and Discounts [Member] | Contract Liabilities [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 1,600

Collaboration Agreements and_10

Collaboration Agreements and Revenues - Roll-forward of Contract Liabilities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Contract with Customer Liability [Line Items]
Beginning balance	$ (54,790)
Ending balance	0
Product [Member]
Contract with Customer Liability [Line Items]
Beginning balance	(1,102)
Additions	(10,623)
Deduction	450
Currency Translation and Other	(117)
Gross Contract Liabilities Balance	(11,392)
Balance Presented Net Against Accounts Receivable	9,759
Ending balance	$ (1,633)

Collaboration Agreements and_11

Collaboration Agreements and Revenues - Summary of Contra-Accounts Receivable Items Related to Product Revenue (Detail) - Product [Member] - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	$ 9,914	$ 1,102
Price Adjustment
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	529	936
Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	3,479	148
Non-key Account Hospital Listing Award [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	5,238	0
Other Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	513	18
Sales Return [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	53	0
Provision for Credit Loss [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	$ 102	$ 0

Collaboration Agreements and_12

Collaboration Agreements and Revenues - Drug Product Revenue - Summary of Drug Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue	$ 44,032	$ 33,174	$ 111,320	$ 248,603
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue	686		8,924
Drug Product Revenue [Member] | Astellas Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue	(3,957)		4,281
Drug Product Revenue [Member] | AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue	$ 4,643		$ 4,643

Collaboration Agreements and_13

Collaboration Agreements and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 44,032		$ 33,174	$ 111,320	$ 248,603
Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	686			8,924
Astellas Agreement [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	100
Astellas Agreement [Member] | Drug Product Revenue [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	4,000
Drug product revenue recognized		$ 8,200
AstraZeneca Agreements [Member] | Drug Product Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	4,643			$ 4,643
AstraZeneca Agreements [Member] | Drug Product Revenue [Member] | U.S./RoW [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 4,600

Collaboration Agreements and_14

Collaboration Agreements and Revenues - Deferred Revenue - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Contract with Customer, Liability [Abstract]
Deferred revenue	$ 0	$ 54,790
AstraZeneca Agreements [Member] | China [Member]
Contract with Customer, Liability [Abstract]
Deferred revenue	$ 3,200

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 155,645	$ 468,609
U.S. treasury notes and bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	125,388	427,506
Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		10,816
Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	247	255
Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	30,010	30,032
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	607,562	554,160
Fair Value, Measurements, Recurring [Member] | U.S. treasury notes and bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	125,388	427,506
Fair Value, Measurements, Recurring [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		10,816
Fair Value, Measurements, Recurring [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	247	255
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	451,917	85,551
Fair Value, Measurements, Recurring [Member] | Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	30,010	30,032
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	577,552	444,005
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. treasury notes and bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	125,388	347,383
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		10,816
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	247	255
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	451,917	85,551
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	30,010	110,155
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. treasury notes and bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	80,123
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
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 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] | Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	30,010	30,032
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] | U.S. treasury notes and bills [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] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		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, 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] | Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 0	$ 0

Fair Value Measurements - Fai_2

Fair Value Measurements - Fair Values of Financial Liabilities Carried at Historical Cost (Detail) - Lease obligations [Member] - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	$ 1,242	$ 1,544
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	0	0
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	0	0
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	$ 1,242	$ 1,544

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
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 liabilities from level 1 to 2	0	0
Transfers of liabilities from level 2 to 1	0	0
Transfers of assets into level 3	0	0
Transfers of assets out of level 3	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	Sep. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Right-of-use assets - cost	$ 50,220	$ 49,909
Accumulated amortization	(18,192)	(10,307)
Finance lease right-of-use assets, net	32,028	39,602
Right-of-use assets - cost	2,796	2,736
Accumulated amortization	(1,554)	(805)
Operating lease right-of-use assets, net	1,242	1,931
Total lease assets	33,270	41,533
Finance lease liabilities	12,311	12,351
Operating lease liabilities	770	983
Finance lease liabilities	28,514	37,610
Operating lease liabilities	472	942
Total lease liabilities	$ 42,067	$ 51,886

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Finance lease cost:
Amortization of right-of-use assets	$ 2,639	$ 2,580	$ 7,886	$ 7,720
Interest on lease liabilities	462	578	1,511	1,826
Operating lease cost	304	290	868	579
Sublease income	(301)	(310)	(899)	(1,135)
Total lease cost	$ 3,104	$ 3,138	$ 9,366	$ 8,990

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 812	$ 540
Operating cash flows from finance leases	1,468	1,640
Financing cash flows from finance leases	9,254	8,810
Right-of-use assets obtained in exchange for new lease liabilities:
Finance leases	434	49,784
Operating leases	$ 55	$ 2,723

Leases - Schedule of Lease Term

Leases - Schedule of Lease Term and Discount Rate (Detail)	Sep. 30, 2020	Dec. 31, 2019
Weighted-average remaining lease term (years):
Finance leases	3 years 1 month 6 days	3 years 7 months 6 days
Operating leases	1 year 7 months 6 days	2 years 1 month 6 days
Weighted-average discount rate:
Finance leases	4.39%	4.42%
Operating leases	4.73%	4.75%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Detail) $ in Thousands	Sep. 30, 2020USD ($)
Finance Leases
2020 (Remaining three month period)	$ 3,542
2021	13,683
2022	13,883
2023	12,524
Total future lease payments	43,632
Less: Interest	(2,807)
Present value of lease liabilities	40,825
Operating Leases
2020 (Remaining three month period)	245
2021	714
2022	329
2023	0
Total future lease payments	1,288
Less: Interest	(46)
Present value of lease liabilities	$ 1,242

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Cash	$ 80,551	$ 40,715
Money market funds	451,917	85,551
Total cash and cash equivalents	$ 532,468	$ 126,266

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail)	Dec. 31, 2019USD ($)Milestone	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 126,266,000	$ 532,468,000		$ 532,468,000
Contractual maturities of available-for-sale investments				1 year
Other-than-temporary impairment loss		0	$ 0	$ 0	$ 0
Provision to write-down excess and obsolete inventory			$ 0		$ 0
Number of regulatory milestones | Milestone	2
Unbilled contract assets	$ 180,000,000	0		0
Billed contract assets							$ 50,000,000
API product price change in estimated variable consideration	36,324,000	3,957,000		3,957,000
API product price adjustment	36,324,000	3,957,000		3,957,000
Accrued long term co promotion liability current		14,800,000		14,800,000
Accrued long-term co-promotion expenses	53,071,000	26,344,000		26,344,000
Europe [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets						$ 130,000,000
Astellas Agreement [Member] | Europe [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets	130,000,000
Billed contract assets						$ 130,000,000
AstraZeneca Agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets							$ 50,000,000
Accrued long term co promotion liability current		14,800,000		14,800,000
Reversal of previously accrued long-term co-promotion expenses		84,400,000
AstraZeneca Agreements [Member] | Long-Term Liabilities [Member]
Schedule of Available-for-sale Securities [Line Items]
Accrued long-term co-promotion expenses		26,300,000		26,300,000
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets	50,000,000
Foreign subsidiaries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 11,900,000	$ 51,200,000		$ 51,200,000

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 155,118	$ 467,850
Gross Unrealized Holding Gains	527	784
Gross Unrealized Holding Losses	0	(25)
Fair Value	155,645	468,609
U.S. treasury notes and bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	124,993	426,995
Gross Unrealized Holding Gains	395	536
Gross Unrealized Holding Losses	0	(25)
Fair Value	125,388	427,506
Certificate of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,000	30,000
Gross Unrealized Holding Gains	10	32
Gross Unrealized Holding Losses	0	0
Fair Value	30,010	30,032
Bond and mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		10,730
Gross Unrealized Holding Gains		86
Gross Unrealized Holding Losses		0
Fair Value		10,816
Equity investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	125	125
Gross Unrealized Holding Gains	122	130
Gross Unrealized Holding Losses	0	0
Fair Value	$ 247	$ 255

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Investments [Abstract]
Raw materials	$ 1,152	$ 325
Work-in-progress	5,616	2,264
Finished goods	5,034	4,298
Total inventories	$ 11,803	$ 6,887

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Unbilled contract assets	$ 0	$ 180,000
Deferred revenues from associated contracts	0	(54,790)
Net unbilled contract assets	0	125,210
Prepaid assets	5,549	6,464
Other current assets	6,014	1,717
Total prepaid expenses and other current assets	$ 11,563	$ 133,391

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 143,804	$ 143,107
Less: accumulated depreciation	(107,651)	(100,364)
Property and equipment, net	36,153	42,743
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	101,162	101,548
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	17,890	17,329
Machinery [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,012	8,217
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	9,124	8,399
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,110	5,822
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,506	$ 1,792

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 29,396	$ 16,279
API product price adjustment	3,957	36,324
Payroll and related accruals	19,606	19,784
Accrued co-promotion expenses - current	14,836	0
Property taxes and other	6,057	2,044
Professional services	7,384	4,842
Other	9,336	4,543
Total accrued and other current liabilities	$ 90,572	$ 83,816

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Liabilities Noncurrent [Abstract]
Accrued long-term co-promotion expenses	$ 26,344	$ 53,071
Other long-term tax liabilities	8,637	8,913
Operating lease liabilities, non-current	472	942
Other	2,186	1,340
Total other long-term liabilities	$ 37,639	$ 64,266

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Recorded Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 17,891	$ 14,793	$ 52,451	$ 48,865
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	11,236	10,185	32,653	30,214
Selling, general and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 6,655	$ 4,608	$ 19,798	$ 18,651

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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
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 3 months 18 days	5 years 8 months 12 days	5 years 3 months 18 days
Expected volatility	59.00%	67.80%	67.70%	67.90%
Risk-free interest rate	0.30%	1.70%	0.80%	2.40%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 22.48	$ 25.17	$ 18.11	$ 32.44
2014 Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	49.50%	48.10%	49.50%	48.10%
Expected volatility, maximum	77.10%	62.10%	77.10%	62.10%
Risk-free interest rate, minimum	0.20%	1.30%	0.20%	1.30%
Risk-free interest rate, maximum	2.90%	2.90%	2.90%	2.90%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 17	$ 19.27	$ 17.74	$ 19.53
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 ($) $ in Thousands	1 Months Ended	3 Months Ended				9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Accounts receivable from related party	$ 4,715	$ 4,715				$ 4,715		$ 4,845
Accrued liabilities to related party	4,135	4,135				4,135		36,883
Unbilled contract asset	0	0				0		180,000
Net unbilled contract asset	0	0				0		125,210
Deferred revenue	0	0				0		54,790
Other assets from related party	1,483	1,483				1,483		0
Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset			$ 130,000
Astellas Agreement [Member]
Related Party Transaction [Line Items]
Drug product revenue from a related party		(3,957)			$ 0	4,281	$ 0
Astellas Agreement [Member] | Japan [Member]
Related Party Transaction [Line Items]
Deferred revenue	164	164				164
Astellas Agreement [Member] | Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset								130,000
Deferred revenue	2,096	2,096				2,096
Astellas [Member] | Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset			130,000
Net unbilled contract asset								125,200
Deferred revenue								4,800
Astellas [Member] | API Shipment [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements		(4,000)
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements		4,700			15,500	14,200	155,000
Drug product revenue from a related party			$ 8,200			4,300
Expense related to collaboration agreements		200			$ 900	500	$ 2,200
Accounts receivable from related party	4,700	4,700				4,700		4,800
Accrued liabilities to related party	4,100	4,100				4,100		36,900
Amount paid to related party				$ 36,300
Astellas [Member] | Astellas Agreement [Member] | Japan [Member]
Related Party Transaction [Line Items]
Accrued liabilities to related party				$ 4,000				$ 36,300
Falikang [Member]
Related Party Transaction [Line Items]
Investment	$ 1,500	1,500				1,500
Percentage of outstanding shares owned	51.10%
Other assets from related party	$ 1,500	1,500				1,500
Miscellaneous receivables	$ 200	$ 200				$ 200

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	$ 33.1
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	16.7
Research and Pre-Clinical Stage Development Programs [Member]
Commitments And Contingencies [Line Items]
Future milestone payments	10.9
Other Purchases [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	$ 5.5