FibroGen (FGEN) 10-Q 6 Aug 20 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	FGEN
Entity Registrant Name	FIBROGEN, INC.
Entity Central Index Key	0000921299
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity File Number	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		90,355,096

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 429,269	$ 126,266
Short-term investments	256,317	407,491
Accounts receivable, net ($12,090 and $4,845 from a related party)	26,519	28,455
Inventories	8,582	6,887
Prepaid expenses and other current assets ($0 and $125,210 from a related party)	6,481	133,391
Total current assets	727,168	702,490
Restricted time deposits	2,072	2,072
Long-term investments	229	61,118
Property and equipment, net	36,984	42,743
Finance lease right-of-use assets	34,368	39,602
Other assets	6,862	9,372
Total assets	807,683	857,397
Current liabilities:
Accounts payable	5,015	6,088
Accrued and other current liabilities ($216 and $36,883 to a related party)	50,464	83,816
Deferred revenue	9,813	490
Finance lease liabilities, current	12,279	12,351
Total current liabilities	77,571	102,745
Long-term portion of lease obligations	940	1,141
Product development obligations	16,959	16,780
Deferred revenue, net of current	138,242	99,449
Finance lease liabilities, non-current	31,586	37,610
Other long-term liabilities	127,242	64,266
Total liabilities	392,540	321,991
Commitments and Contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at June 30, 2020 and December 31, 2019	0	0
Common stock, $0.01 par value; 225,000 shares authorized at March 31, 2020 and December 31, 2019; 90,228 and 87,657 shares issued and outstanding at June 30, 2020 and December 31, 2019	902	877
Additional paid-in capital	1,344,912	1,300,725
Accumulated other comprehensive loss	(1,561)	(747)
Accumulated deficit	(948,381)	(784,720)
Total stockholders’ equity	395,872	516,135
Non-controlling interests	19,271	19,271
Total equity	415,143	535,406
Total liabilities, stockholders’ equity and non-controlling interests	$ 807,683	$ 857,397

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Accounts receivable from related party	$ 12,090	$ 4,845
Prepaid expenses and other current assets from related party	0	125,210
Accrued and other current liabilities to related party	$ 216	$ 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	90,228,000	87,657,000
Common stock, shares outstanding	90,228,000	87,657,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Total revenue	$ 42,888	$ 191,566	$ 67,288	$ 215,429
Operating costs and expenses:
Cost of goods sold	$ 3,076	$ 0	$ 4,047	$ 0
Cost, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Research and development	$ 61,414	$ 52,008	$ 116,315	$ 102,505
Selling, general and administrative	63,535	26,739	113,138	48,948
Total operating costs and expenses	128,025	78,747	233,500	151,453
Income (loss) from operations	(85,137)	112,819	(166,212)	63,976
Interest and other, net
Interest expense	(651)	(736)	(1,284)	(1,507)
Interest income and other, net	644	4,125	3,810	8,303
Total interest and other, net	(7)	3,389	2,526	6,796
Income (loss) before income taxes	(85,144)	116,208	(163,686)	70,772
Provision for (benefit from) income taxes	169	205	(25)	180
Net income (loss)	$ (85,313)	$ 116,003	$ (163,661)	$ 70,592
Net income (loss) per share:
Basic	$ (0.95)	$ 1.34	$ (1.84)	$ 0.82
Diluted	$ (0.95)	$ 1.26	$ (1.84)	$ 0.77
Weighted average number of common shares used to calculate net income (loss) per share:
Basic	89,451	86,445	88,835	86,077
Diluted	89,451	91,728	88,835	92,069
License Revenue [Member]
Revenue:
Total revenue	$ 0	$ 150,581	$ 0	$ 150,581
Development and Other Revenue [Member]
Revenue:
Total revenue	18,957	40,985	38,402	64,848
Product Revenue, Net [Member]
Revenue:
Total revenue	15,693	0	20,648	0
Drug Product Revenue [Member]
Revenue:
Total revenue	$ 8,238	$ 0	$ 8,238	$ 0

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - Astellas Agreement [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
License and milestone revenue from a related party	$ 0	$ 117,470	$ 0	$ 117,470
Collaboration services and other revenue from a related party	4,766	17,223	9,503	22,082
Drug product revenue from a related party	$ 8,238	$ 0	$ 8,238	$ 0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (85,313)	$ 116,003	$ (163,661)	$ 70,592
Other comprehensive income (loss):
Foreign currency translation adjustments (Note 1)	(1,615)	(180)	(1,334)	111
Available-for-sale investments:
Unrealized gain on investments, net of tax effect	(1,129)	655	520	1,097
Other comprehensive income, net of taxes	(2,744)	475	(814)	1,208
Comprehensive income (loss)	$ (88,057)	$ 116,478	$ (164,475)	$ 71,800

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)	70,592		$ 0		0		0		70,592		0
Change in unrealized gain or loss on investments	1,097		0		0		1,097		0		0
Foreign currency translation adjustments	111		0		0		111		0		0
Shares issued from stock plans, net of payroll taxes paid	5,272		$ 14		5,258		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			1,414,970
Stock-based compensation	34,072		$ 0		34,072		0		0		0
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
Balance at Mar. 31, 2019	508,494		$ 861		1,242,460		(937)		(753,161)		19,271
Balance, Shares at Mar. 31, 2019			86,129,564
Net income (loss)	116,003		$ 0		0		0		116,003		0
Change in unrealized gain or loss on investments	655		0		0		655		0		0
Foreign currency translation adjustments	(180)		0		0		(180)		0		0
Shares issued from stock plans, net of payroll taxes paid	5,688		$ 7		5,681		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			717,508
Stock-based compensation	17,642		$ 0		17,642		0		0		0
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
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)	(163,661)		$ 0		0		0		(163,661)		0
Change in unrealized gain or loss on investments	520		0		0		520		0		0
Foreign currency translation adjustments	(1,334)		0		0		(1,334)		0		0
Shares issued from stock plans, net of payroll taxes paid	9,652		$ 25		9,627		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			2,570,804
Stock-based compensation	34,560		$ 0		34,560		0		0		0
Balance at Jun. 30, 2020	415,143		$ 902		1,344,912		(1,561)		(948,381)		19,271
Balance, Shares at Jun. 30, 2020			90,228,293
Balance at Mar. 31, 2020	477,629		$ 889		1,319,354		1,183		(863,068)		19,271
Balance, Shares at Mar. 31, 2020			88,895,630
Net income (loss)	(85,313)		$ 0		0		0		(85,313)		0
Change in unrealized gain or loss on investments	(1,129)		0		0		(1,129)		0		0
Foreign currency translation adjustments	(1,615)		0		0		(1,615)		0		0
Shares issued from stock plans, net of payroll taxes paid	7,927		$ 13		7,914		0		0		0
Shares issued from stock plans, net of payroll taxes paid, Shares			1,332,663
Stock-based compensation	17,644		$ 0		17,644		0		0		0
Balance at Jun. 30, 2020	$ 415,143		$ 902		$ 1,344,912		$ (1,561)		$ (948,381)		$ 19,271
Balance, Shares at Jun. 30, 2020			90,228,293

Condensed Consolidated Statem_5

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net income (loss)	$ (163,661)	$ 70,592
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	5,737	5,523
Amortization of finance lease right-of-use assets	5,247	5,140
Net accretion of discount on investments	(22)	(2,457)
Unrealized loss (gain) on equity investments	15	(59)
Gain on disposal of property and equipment	0	(10)
Stock-based compensation	34,560	34,072
Tax benefit on unrealized gain on available-for-sale securities	(138)	0
Realized loss on sales of available-for-sale securities	258	0
Changes in operating assets and liabilities:
Accounts receivable, net	1,903	57,231
Inventories	(2,016)	(1,981)
Prepaid expenses and other current assets	126,874	(131,803)
Other assets	4,025	(200)
Accounts payable	(1,060)	(5,079)
Accrued and other liabilities	(33,501)	917
Deferred revenue	48,117	(46,818)
Accrued interest for finance lease liabilities	(115)	241
Other long-term liabilities	63,956	8,519
Net cash provided by (used in) operating activities	90,179	(6,172)
Investing activities
Purchases of property and equipment	(1,185)	(2,206)
Advanced payment made for acquisition	(1,419)	0
Purchases of available-for-sale securities and term deposit	(38)	(105,511)
Proceeds from sales of available-for-sale securities	10,606	0
Proceeds from maturities of investments	201,900	100,000
Net cash provided by (used in) investing activities	209,864	(7,717)
Financing activities
Repayments of finance lease liabilities	(5,992)	(5,850)
Repayments of lease obligations	(201)	(202)
Cash paid for payroll taxes on restricted stock unit releases	(6,858)	(8,065)
Proceeds from issuance of common stock	16,510	13,337
Net cash provided by (used in) financing activities	3,459	(780)
Effect of exchange rate change on cash and cash equivalents	(499)	(2)
Net increase (decrease) in cash and cash equivalents	303,003	(14,671)
Total cash and cash equivalents at beginning of period	126,266	89,258
Total cash and cash equivalents at end of period	$ 429,269	$ 74,587

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 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 for the treatment of anemia caused by chronic kidney disease (“CKD”) in dialysis and non-dialysis patients. Evrenzo® (roxadustat) is also approved in Japan for the treatment of anemia associated with CKD in dialysis patients. In January 2020, Astellas Pharma Inc. (“Astellas”) submitted a supplemental New Drug Application (“NDA”) in Japan for the treatment of anemia in non-dialysis CKD patients. 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 both idiopathic pulmonary fibrosis and pancreatic cancer. Pamrevlumab is also currently in a Phase 2 trial for Duchenne muscular dystrophy and is in Phase 2/3 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. 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”). 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 June 30, Six Months Ended June 30, 2020 2019 2020 2019 Net income (loss) $ (85,313 ) $ 116,003 $ (163,661 ) $ 70,592 Weighted average shares used to compute net income (loss) per share: Basic 89,451 86,445 88,835 86,077 Dilutive effect of potential common shares — 5,283 — 5,992 Diluted 89,451 91,728 88,835 92,069 Net income (loss) per share: Basic $ (0.95 ) $ 1.34 $ (1.84 ) $ 0.82 Diluted $ (0.95 ) $ 1.26 $ (1.84 ) $ 0.77 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 three and six months ended June 30, 2020, 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 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 normal worldwide healthcare system, as well as an impact on its roxadustat sales in China due to the social distancing and other restrictions put in place, particularly during February and March. 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 (“ASU 2016-13”). This guidance is intended to provide financial statement users with more decision-useful information about the expected credit losses on financial instrume nts and other commitments to extend credit held by a reporting entity at each reporting date. This guidance requires the measurement of financial assets with a methodology that reflects expected credit losses and requires consideration of a broader range o f reasonable and supportable information to inform credit loss estimates. This guidance requires an impairment model, known as the current expected credit loss model, which is based on expected losses rather than incurred losses. Entities are required to c arry an allowance for expected credit losses for financial assets, including most debt instruments (except those carried at fair value) and trade receivables. In November 2019, the FASB issued ASU No. 2019-11, Codification Improvements to Topic 326, Financial Instruments-Credit Losses (“ASU 2019-11”) , which has the same effective dates and transition requirements as ASU 2016 - 13 . ASU 2016-13 and ASU 2019-11 were effective for annual reporting periods beginning af ter December 15, 2019 including interim periods. The Company’s investment portfolio primarily consists of U.S. Treasury bills and notes carried at fair value, which is required to follow the impairment model under Topic 326. The Company adopted this guidan ce on January 1, 2020 . Based on the composition of the Company’s trade receivables and investment portfolio, economic conditions and historical credit loss activity, t he adoption of this guidance did not have material impact to the Company’s condensed cons olidated financial statements. 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: 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 as of June 30, 2020. 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 six months ended June 30, 2020 and the allowance for doubtful accounts as of June 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 the uncollectability of an available-for-sale security is confirmed 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 control of 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 drug revenue 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 (“NHSA”) released price guidance for roxadustat under 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 and for product within one year of 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 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 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 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 Agreements and Re

Collaboration Agreements and Revenues	6 Months Ended
	Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements and Revenues	2. Collaboration Agreements and Revenues Astellas Agreements Japan Agreement In June 2005, the Company entered into a collaboration agreement with Astellas for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). Under the Japan Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $132.5 million in potential milestone payments, comprised of (i) up to $22.5 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of July 2016), (ii) up to $95.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $15.0 million in milestone payments upon the achievement of specified commercial sales milestone. The aggregate amount of consideration received through June 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 June 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 six months ended June 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 AB (“AstraZeneca”) for the development and commercialization of roxadustat for the treatment of anemia in the U.S. and all other countries in the world, other than China, not previously licensed under the Astellas Europe and Astellas Japan Agreements (“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 June 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 $0.4 China Agreement Effective July 30, 2013, the Company (through its subsidiaries affiliated with China) entered into a collaboration agreement with AstraZeneca for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in China (“China Agreement”). Under the terms of the China Agreement, AstraZeneca agreed to pay upfront consideration totaling $28.2 million (such amounts were fully received in 2014). Under the China Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $348.5 million in potential milestone payments, comprised of (i) up to $15.0 million in milestone payments upon achievement of specified clinical and development milestone events, (ii) up to $146.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $187.5 million in milestone payments upon the achievement of specified commercial sales and other events. The China Agreement is structured as a 50/50 profit or loss share (as defined) 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 through June 30, 2020 totals $77.2 million. In December 2019, roxadustat was included on the updated National Reimbursement Drug List (“NRDL”) released by China’s NHSA 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 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 fourth quarter of 2019. This milestone payment was received during the first quarter of 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. On July 8, 2020, FibroGen Cayman, FibroGen Beijing and FibroGen International (Hong Kong) Limited (collectively, “FibroGen China”) and AstraZeneca (together with FibroGen China, the “Parties”) entered into an amendment, effective July 1, 2020, to the China Agreement, relating to the development and commercialization of roxadustat in China. See Note 10 for details. 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 June 30, Six Months Ended June 30, Agreement Performance Obligation 2020 2019 2020 2019 Japan License revenue $ — $ — $ — $ — Development revenue $ 164 $ 369 $ 327 $ 615 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 June 30, 2020 Deferred Revenue at June 30, 2020 Total Consideration Through June 30, 2020 License $ 86,024 $ — $ 86,024 Development revenue 15,458 183 15,641 Total license and development revenue $ 101,482 $ 183 $ 101,665 The revenue recognized under the Japan Agreement for the three months ended June 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 June 30, Six Months Ended June 30, Agreement Performance Obligation 2020 2019 2020 2019 Europe License revenue $ — $ 117,470 $ — $ 117,470 Development revenue $ 4,602 $ 16,854 $ 9,176 $ 21,467 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 June 30, 2020 Deferred Revenue at June 30, 2020 Total Consideration Through June 30, 2020 License $ 487,951 $ — $ 487,951 Development revenue 240,184 2,338 242,522 Total license and development revenue $ 728,135 $ 2,338 $ 730,473 The revenue recognized under the Europe Agreement for the three months ended June 30, 2020 included an increase in revenue of $1.6 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 $31.7 million of variable consideration from estimated future co-development billing and is expected to be recognized over the remaining development service period. Amounts recognized as revenue under the U.S./RoW Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2020 2019 2020 2019 U.S. / RoW and China License revenue $ — $ 33,111 $ — $ 33,111 Development revenue 13,750 23,762 28,305 42,766 China performance obligation $ 441 $ — $ 594 $ — The transaction price related to consideration received and accounts receivable has been allocated to each of the following performance obligations under the U.S./RoW Agreement and China Agreement, along with any associated deferred revenue as follows (in thousands): U.S. / RoW and China Agreements Cumulative Revenue Through June 30, 2020 Deferred Revenue at June 30, 2020 Total Consideration Through June 30, 2020 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 521,572 4,547 526,119 China performance obligation 684 140,973 141,657 Total license and development revenue $ 864,100 $ 145,520 $ 1,009,620 The revenue recognized under the U.S./RoW Agreement for the three months ended June 30, 2020 included a decrease of $0.2 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 $90.1 million of variable consideration from estimated future co-development billing and is expected to be recognized over the remaining development service period, except for amounts allocated to the China performance obligation, which are expected to be recognized in a pattern consistent with estimated deliveries of the commercial drug product. Product Revenue, Net The Company started roxadustat commercial sales in China in the third quarter of 2019. Product revenue 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 June 30, 2020 Six Months Ended June 30, 2020 Gross revenue $ 19,833 $ 25,205 Non-key account hospital listing award (2,566 ) (2,566 ) Contractual sales rebate (1,372 ) (1,748 ) Other discounts and rebates (202 ) (243 ) Product revenue, net $ 15,693 $ 20,648 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. During the three months ended June 30, 2020, a $2.6 million of non-key account hospital listing award was recorded as a reduction to the revenue, which was 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 six months ended June 30, 2020, the contractual sales rebate was $1.4 million and $1.7 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 period. The rebates and discounts that the Company’s pharmaceutical distributors have earned are eligible to be applied against their 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 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 June 30, 2020 Contract liabilities $ (1,102 ) $ (4,907 ) $ 16 $ 9 $ (5,984 ) $ 5,595 $ (389 ) As of June 30, 2020, the total rebates and discounts as reductions to gross accounts receivable was $5.6 million, and the total contract liabilities was $0.4 million, which was included in accrued and other current liabilities in the condensed consolidated balance sheet. The above-mentioned contra-accounts receivable items related to product revenue consisted of the following (in thousands): June 30, 2020 December 31, 2019 Price adjustment $ 935 $ 936 Contractual sales rebate 1,878 148 Non-key account hospital listing award 2,567 — Other discounts and rebates 260 18 Provision for credit loss 84 — Total reductions to gross accounts receivable $ 5,724 $ 1,102 Drug Product Revenue 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. During the three months ended June 30, 2020, the Company fulfilled the 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 yield and the related cost to convert the API to bulk product tablets. 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 launch of the products within China. As of June 30, 2020, approximately $2.7 million of the related deferred revenue 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	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The fair values of the Company’s financial assets that are measured on a recurring basis are as follows (in thousands): June 30, 2020 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 176,028 $ 50,151 $ — $ 226,179 Equity investments 229 — — 229 Money market funds 230,561 — — 230,561 Certificate of deposit — 30,138 — 30,138 Total $ 406,818 $ 80,289 $ — $ 487,107 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): June 30, 2020 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,343 $ 1,343 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	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases	4. Leases The Company’s lease assets and related lease liabilities were as follows (in thousands): Balance Sheet Line Item June 30, 2020 December 31, 2019 Assets Finance: Right-of-use assets - cost $ 49,903 $ 49,909 Accumulated amortization (15,535 ) (10,307 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 34,368 39,602 Operating: Right-of-use assets - cost 2,647 2,736 Accumulated amortization (1,270 ) (805 ) Operating lease right-of-use assets, net Other assets 1,377 1,931 Total lease assets $ 35,745 $ 41,533 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 12,279 $ 12,351 Operating lease liabilities Accrued and other current liabilities 801 983 Non-current: Finance lease liabilities Finance lease liabilities, non-current 31,586 37,610 Operating lease liabilities Other long-term liabilities 572 942 Total lease liabilities $ 45,238 $ 51,886 The components of lease expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Statement of Operations Line Item 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 $ 2,653 $ 2,571 $ 5,247 $ 5,140 Interest on lease liabilities Interest expense 534 609 1,049 1,249 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 255 163 564 289 Sublease income Selling, general and administrative expenses (306 ) (237 ) (598 ) (824 ) Total lease cost $ 3,136 $ 3,106 $ 6,262 $ 5,854 Supplemental cash flow information related to leases were as follows (in thousands): Six Months Ended June 30, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 433 $ 191 Operating cash flows from finance leases 1,010 1,053 Financing cash flows from finance leases 5,992 5,850 Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 144 49,676 Operating leases $ 5 $ 1,212 Lease term and discount rate were as follows: June 30, 2020 December 31, 2019 Weighted-average remaining lease term (years): Finance leases 3.4 3.6 Operating leases 1.8 2.1 Weighted-average discount rate: Finance leases 4.39 % 4.42 % Operating leases 4.73 % 4.75 % Maturities of lease liabilities as of June 30, 2020 are as follows (in thousands): Year Ending Finance Leases Operating Leases 2020 (Remaining six month period) $ 7,047 $ 463 2021 13,680 663 2022 13,883 305 2023 12,523 — Total future lease payments 47,133 1,431 Less: Interest (3,268 ) (58 ) Present value of lease liabilities $ 43,865 $ 1,373

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	5. Balance Sheet Components Cash and Cash Equivalents Cash and cash equivalents consisted of the following (in thousands): June 30, 2020 December 31, 2019 Cash $ 198,708 $ 40,715 Money market funds 230,561 85,551 Total cash and cash equivalents $ 429,269 $ 126,266 At June 30, 2020 and December 31, 2019, a total of $32.8 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): June 30, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 225,117 $ 1,062 $ — $ 226,179 Certificates of deposit 30,000 138 — 30,138 Equity investments 125 104 — 229 Total investments $ 255,242 $ 1,304 $ — $ 256,546 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 June 30, 2020, all of the available-for-sale investments had contractual maturities within one year. During the three and six months ended June 30, 2020 and 2019, the Company did not recognize any other-than-temporary impairment loss. Inventories Inventories consisted of the following (in thousands): June 30, 2020 December 31, 2019 Raw materials $ 327 $ 325 Work-in-progress 3,815 2,264 Finished goods 4,440 4,298 Total inventories $ 8,582 $ 6,887 The provision to write-down excess and obsolete inventory was immaterial for the three and six months ended June 30, 2020. Prepaid expenses and other current assets Prepaid expenses and other current assets consisted of the following (in thousands): June 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 4,429 6,464 Other current assets 2,052 1,717 Total prepaid expenses and other current assets $ 6,481 $ 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 2 for details. Property and Equipment Property and equipment consisted of the following (in thousands): June 30, 2020 December 31, 2019 Leasehold improvements $ 100,159 $ 101,548 Laboratory equipment 17,362 17,329 Machinery 7,660 8,217 Computer equipment 8,930 8,399 Furniture and fixtures 5,873 5,822 Construction in progress 1,225 1,792 Total property and equipment $ 141,209 $ 143,107 Less: accumulated depreciation (104,225 ) (100,364 ) Property and equipment, net $ 36,984 $ 42,743 Accrued Liabilities Accrued liabilities consisted of the following (in thousands): June 30, 2020 December 31, 2019 Preclinical and clinical trial accruals $ 21,691 $ 16,279 API product price adjustment — 36,324 Payroll and related accruals 14,266 19,784 Property taxes and other 1,145 2,044 Professional services 5,653 4,842 Other 7,709 4,543 Total accrued liabilities $ 50,464 $ 83,816 The amount 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. The amount was fully paid during the first quarter of 2020. Other Long-term Liabilities Other long-term liabilities consisted of the following (in thousands): June 30, 2020 December 31, 2019 Accrued long-term co-promotional expenses $ 116,230 $ 53,071 Other long-term tax liabilities 8,653 8,913 Operating lease liabilities, non-current 572 942 Other 1,787 1,340 Total other long-term liabilities $ 127,242 $ 64,266 The accrued long-term co-promotional expenses of $116.2 million and $53.1 million as of June 30, 2020 and December 31, 2019, respectively, were related to the estimated amount payable to AstraZeneca for its sales and marketing efforts associated with the commercial launch and sales for roxadustat in China. The payment for such amount is not expected to occur within the next year. On July 8, 2020, the Parties into an amendment to the China Agreement, relating to the development and commercialization of roxadustat in China. As a result, such accrued long-term co-promotional expenses will be reduced by approximately $82 million in the third quarter of 2020. See Note 10 for details.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	6. Stock-Based Compensation Stock-based compensation expense was recorded to research and development and selling, general and administrative expense as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 10,780 $ 10,450 $ 21,417 $ 20,028 Selling, general and administrative 6,864 7,192 13,143 14,044 Total stock-based compensation expense $ 17,644 $ 17,642 $ 34,560 $ 34,072 The assumptions used to estimate the fair value of stock options granted and purchases under the Company’s 2014 Employee Share Purchase Plan (“ESPP”) using the Black-Scholes option valuation model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Stock Options Expected term (in years) 5.5 5.3 5.7 5.3 Expected volatility 69.2 % 68.2 % 68.4 % 67.9 % Risk-free interest rate 0.4 % 2.0 % 0.8 % 2.5 % Expected dividend yield — — — — Weighted average estimated fair value $ 21.72 $ 24.40 $ 17.75 $ 33.20 ESPPs Expected term (in years) 0.5 – 2.0 0.5 – 2.0 0.5 – 2.0 0.5 – 2.0 Expected volatility 49.5 – 77.1 % 48.1 – 62.1 % 49.5 – 77.1 % 48.1 – 62.1 % Risk-free interest rate 0.2 – 2.9 % 1.3 – 2.9 % 0.2 – 2.9 % 1.3 – 2.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 17.82 $ 19.07 $ 18.11 $ 19.65

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes Provision for (benefit from) income tax for the three and six months ended June 30, 2020 were primarily due to the tax effect arising from other comprehensive income related to available-for-sale securities, and foreign taxes. Provisions for income tax for the three and six months ended June 30, 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	6 Months Ended
	Jun. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	8. 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 $4.8 million and $134.7 million for the three months ended June 30, 2020 and 2019, respectively, and $9.5 million and $139.6 million for the six months ended June 30, 2020 and 2019, respectively. For the three and six months ended June 30, 2020, the Company also recorded $8.2 million drug product revenue from Astellas. The Company recorded expense related to collaboration agreements with Astellas of $0.2 million and $0.8 million during the three months ended June 30, 2020 and 2019, respectively, and $0.3 million and $1.3 million during the six months ended June 30, 2020 and 2019, respectively. As of June 30, 2020 and December 31, 2019, accounts receivable from Astellas were $12.1 million and $4.8 million, respectively, and amounts due to Astellas were $0.2 million and $36.9 million, respectively. The amounts due to Astellas as of December 31, 2019 included $36.3 million of a change in estimated variable consideration related to the API product revenue recognized in 2018, at the time the roxadustat listed price was issued by the Japanese Ministry of Health, Labour and Welfare. Such amount 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, respectively, 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 2 for details.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Contract Obligations As of June 30, 2020, the Company had outstanding total non-cancelable contract obligations of $26.2 million, including $14.2 million for manufacture and supply of roxadustat, $10.9 million for future milestone payments for research and pre-clinical stage development programs, and $1.1 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 United States, arising in the ordinary course of its business or otherwise. The Company accrues amounts, to the extent they can be reasonably estimated, that the Company believes will result in a probable loss (including, among other things, probable settlement value), to adequately address any liabilities related to legal proceedings and other loss contingencies. A loss or a range of loss is disclosed when it is reasonably possible that a material loss will incur and can be estimated, or when it is reasonably possible that the amount of a loss, when material, will exceed the recorded provision. The Company did not have material accruals for any currently active legal action in its condensed consolidated balance sheets as of June 30, 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.

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Event	10. Subsequent Event On July 8, 2020, FibroGen Cayman, FibroGen Beijing, and FibroGen International (Hong Kong) Limited (collectively, “FibroGen China”) and AstraZeneca AB (“AstraZeneca”, and together with FibroGen China, the “Parties”) entered into an amendment, effective July 1, 2020, to the China Agreement, relating to the development and commercialization of roxadustat in China (the “Amendment”). The Amendment provides for the establishment of a jointly owned entity (the “Distribution Entity”) that will perform roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. 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. In July 2020, the Company closed the acquisition of an entity for the purpose of the establishment of the Distribution Entity. While the responsibilities of the Parties under the China Agreement remain largely the same, certain changes were made. The Parties have changed the method under which commercial expenses incurred by AstraZeneca are billed, and the collaboration has been adjusted to more fully account for the cost of manufacturing incurred by FibroGen Beijing. The Company is in the process of evaluating the accounting impacts resulting from the Amendment and the establishment of the Distribution Entity, which is expected to be significant to its consolidated financial statements starting the third quarter of 2020. Among others, the accrued long-term co-promotional expenses related to the estimated amount payable to AstraZeneca for its sales and marketing efforts associated with the commercial launch and sales for roxadustat will be reduced by approximately $82 million in the third quarter of 2020.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 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 for the treatment of anemia caused by chronic kidney disease (“CKD”) in dialysis and non-dialysis patients. Evrenzo® (roxadustat) is also approved in Japan for the treatment of anemia associated with CKD in dialysis patients. In January 2020, Astellas Pharma Inc. (“Astellas”) submitted a supplemental New Drug Application (“NDA”) in Japan for the treatment of anemia in non-dialysis CKD patients. 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 both idiopathic pulmonary fibrosis and pancreatic cancer. Pamrevlumab is also currently in a Phase 2 trial for Duchenne muscular dystrophy and is in Phase 2/3 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. 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”).
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 June 30, Six Months Ended June 30, 2020 2019 2020 2019 Net income (loss) $ (85,313 ) $ 116,003 $ (163,661 ) $ 70,592 Weighted average shares used to compute net income (loss) per share: Basic 89,451 86,445 88,835 86,077 Dilutive effect of potential common shares — 5,283 — 5,992 Diluted 89,451 91,728 88,835 92,069 Net income (loss) per share: Basic $ (0.95 ) $ 1.34 $ (1.84 ) $ 0.82 Diluted $ (0.95 ) $ 1.26 $ (1.84 ) $ 0.77 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 three and six months ended June 30, 2020, 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
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 normal worldwide healthcare system, as well as an impact on its roxadustat sales in China due to the social distancing and other restrictions put in place, particularly during February and March. 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 (“ASU 2016-13”). This guidance is intended to provide financial statement users with more decision-useful information about the expected credit losses on financial instrume nts and other commitments to extend credit held by a reporting entity at each reporting date. This guidance requires the measurement of financial assets with a methodology that reflects expected credit losses and requires consideration of a broader range o f reasonable and supportable information to inform credit loss estimates. This guidance requires an impairment model, known as the current expected credit loss model, which is based on expected losses rather than incurred losses. Entities are required to c arry an allowance for expected credit losses for financial assets, including most debt instruments (except those carried at fair value) and trade receivables. In November 2019, the FASB issued ASU No. 2019-11, Codification Improvements to Topic 326, Financial Instruments-Credit Losses (“ASU 2019-11”) , which has the same effective dates and transition requirements as ASU 2016 - 13 . ASU 2016-13 and ASU 2019-11 were effective for annual reporting periods beginning af ter December 15, 2019 including interim periods. The Company’s investment portfolio primarily consists of U.S. Treasury bills and notes carried at fair value, which is required to follow the impairment model under Topic 326. The Company adopted this guidan ce on January 1, 2020 . Based on the composition of the Company’s trade receivables and investment portfolio, economic conditions and historical credit loss activity, t he adoption of this guidance did not have material impact to the Company’s condensed cons olidated financial statements.
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: 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 as of June 30, 2020. 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 six months ended June 30, 2020 and the allowance for doubtful accounts as of June 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 the uncollectability of an available-for-sale security is confirmed 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 control of 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 drug revenue 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 (“NHSA”) released price guidance for roxadustat under 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 and for product within one year of 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 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 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 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 June 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 June 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 six months ended June 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 AB (“AstraZeneca”) for the development and commercialization of roxadustat for the treatment of anemia in the U.S. and all other countries in the world, other than China, not previously licensed under the Astellas Europe and Astellas Japan Agreements (“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 June 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 $0.4 China Agreement Effective July 30, 2013, the Company (through its subsidiaries affiliated with China) entered into a collaboration agreement with AstraZeneca for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in China (“China Agreement”). Under the terms of the China Agreement, AstraZeneca agreed to pay upfront consideration totaling $28.2 million (such amounts were fully received in 2014). Under the China Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $348.5 million in potential milestone payments, comprised of (i) up to $15.0 million in milestone payments upon achievement of specified clinical and development milestone events, (ii) up to $146.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $187.5 million in milestone payments upon the achievement of specified commercial sales and other events. The China Agreement is structured as a 50/50 profit or loss share (as defined) 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 through June 30, 2020 totals $77.2 million. In December 2019, roxadustat was included on the updated National Reimbursement Drug List (“NRDL”) released by China’s NHSA 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 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 fourth quarter of 2019. This milestone payment was received during the first quarter of 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. On July 8, 2020, FibroGen Cayman, FibroGen Beijing and FibroGen International (Hong Kong) Limited (collectively, “FibroGen China”) and AstraZeneca (together with FibroGen China, the “Parties”) entered into an amendment, effective July 1, 2020, to the China Agreement, relating to the development and commercialization of roxadustat in China. See Note 10 for details.
Product Revenue	Product Revenue, Net The Company started roxadustat commercial sales in China in the third quarter of 2019. Product revenue 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 June 30, 2020 Six Months Ended June 30, 2020 Gross revenue $ 19,833 $ 25,205 Non-key account hospital listing award (2,566 ) (2,566 ) Contractual sales rebate (1,372 ) (1,748 ) Other discounts and rebates (202 ) (243 ) Product revenue, net $ 15,693 $ 20,648 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. During the three months ended June 30, 2020, a $2.6 million of non-key account hospital listing award was recorded as a reduction to the revenue, which was 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 six months ended June 30, 2020, the contractual sales rebate was $1.4 million and $1.7 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 period. The rebates and discounts that the Company’s pharmaceutical distributors have earned are eligible to be applied against their 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 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 June 30, 2020 Contract liabilities $ (1,102 ) $ (4,907 ) $ 16 $ 9 $ (5,984 ) $ 5,595 $ (389 ) As of June 30, 2020, the total rebates and discounts as reductions to gross accounts receivable was $5.6 million, and the total contract liabilities was $0.4 million, which was included in accrued and other current liabilities in the condensed consolidated balance sheet. The above-mentioned contra-accounts receivable items related to product revenue consisted of the following (in thousands): June 30, 2020 December 31, 2019 Price adjustment $ 935 $ 936 Contractual sales rebate 1,878 148 Non-key account hospital listing award 2,567 — Other discounts and rebates 260 18 Provision for credit loss 84 — Total reductions to gross accounts receivable $ 5,724 $ 1,102
Drug Product Revenue	Drug Product Revenue 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. During the three months ended June 30, 2020, the Company fulfilled the 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 yield and the related cost to convert the API to bulk product tablets. 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 launch of the products within China. As of June 30, 2020, approximately $2.7 million of the related deferred revenue 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)	6 Months Ended
	Jun. 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 June 30, Six Months Ended June 30, 2020 2019 2020 2019 Net income (loss) $ (85,313 ) $ 116,003 $ (163,661 ) $ 70,592 Weighted average shares used to compute net income (loss) per share: Basic 89,451 86,445 88,835 86,077 Dilutive effect of potential common shares — 5,283 — 5,992 Diluted 89,451 91,728 88,835 92,069 Net income (loss) per share: Basic $ (0.95 ) $ 1.34 $ (1.84 ) $ 0.82 Diluted $ (0.95 ) $ 1.26 $ (1.84 ) $ 0.77

Collaboration Agreements and _2

Collaboration Agreements and Revenues (Tables)	6 Months Ended
	Jun. 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 June 30, 2020 Six Months Ended June 30, 2020 Gross revenue $ 19,833 $ 25,205 Non-key account hospital listing award (2,566 ) (2,566 ) Contractual sales rebate (1,372 ) (1,748 ) Other discounts and rebates (202 ) (243 ) Product revenue, net $ 15,693 $ 20,648
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 June 30, 2020 Contract liabilities $ (1,102 ) $ (4,907 ) $ 16 $ 9 $ (5,984 ) $ 5,595 $ (389 )
Summary of Contra-Accounts Receivable Items Related to Product Revenue	The above-mentioned contra-accounts receivable items related to product revenue consisted of the following (in thousands): June 30, 2020 December 31, 2019 Price adjustment $ 935 $ 936 Contractual sales rebate 1,878 148 Non-key account hospital listing award 2,567 — Other discounts and rebates 260 18 Provision for credit loss 84 — Total reductions to gross accounts receivable $ 5,724 $ 1,102
Japan [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Japan Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2020 2019 2020 2019 Japan License revenue $ — $ — $ — $ — Development revenue $ 164 $ 369 $ 327 $ 615
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 June 30, 2020 Deferred Revenue at June 30, 2020 Total Consideration Through June 30, 2020 License $ 86,024 $ — $ 86,024 Development revenue 15,458 183 15,641 Total license and development revenue $ 101,482 $ 183 $ 101,665
Europe [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2020 2019 2020 2019 Europe License revenue $ — $ 117,470 $ — $ 117,470 Development revenue $ 4,602 $ 16,854 $ 9,176 $ 21,467
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 June 30, 2020 Deferred Revenue at June 30, 2020 Total Consideration Through June 30, 2020 License $ 487,951 $ — $ 487,951 Development revenue 240,184 2,338 242,522 Total license and development revenue $ 728,135 $ 2,338 $ 730,473
U.S./RoW and China [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the U.S./RoW Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Performance Obligation 2020 2019 2020 2019 U.S. / RoW and China License revenue $ — $ 33,111 $ — $ 33,111 Development revenue 13,750 23,762 28,305 42,766 China performance obligation $ 441 $ — $ 594 $ —
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 June 30, 2020 Deferred Revenue at June 30, 2020 Total Consideration Through June 30, 2020 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 521,572 4,547 526,119 China performance obligation 684 140,973 141,657 Total license and development revenue $ 864,100 $ 145,520 $ 1,009,620

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 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): June 30, 2020 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 176,028 $ 50,151 $ — $ 226,179 Equity investments 229 — — 229 Money market funds 230,561 — — 230,561 Certificate of deposit — 30,138 — 30,138 Total $ 406,818 $ 80,289 $ — $ 487,107 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): June 30, 2020 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,343 $ 1,343 December 31, 2019 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,544 $ 1,544

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 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 June 30, 2020 December 31, 2019 Assets Finance: Right-of-use assets - cost $ 49,903 $ 49,909 Accumulated amortization (15,535 ) (10,307 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 34,368 39,602 Operating: Right-of-use assets - cost 2,647 2,736 Accumulated amortization (1,270 ) (805 ) Operating lease right-of-use assets, net Other assets 1,377 1,931 Total lease assets $ 35,745 $ 41,533 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 12,279 $ 12,351 Operating lease liabilities Accrued and other current liabilities 801 983 Non-current: Finance lease liabilities Finance lease liabilities, non-current 31,586 37,610 Operating lease liabilities Other long-term liabilities 572 942 Total lease liabilities $ 45,238 $ 51,886
Components of Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Statement of Operations Line Item 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 $ 2,653 $ 2,571 $ 5,247 $ 5,140 Interest on lease liabilities Interest expense 534 609 1,049 1,249 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 255 163 564 289 Sublease income Selling, general and administrative expenses (306 ) (237 ) (598 ) (824 ) Total lease cost $ 3,136 $ 3,106 $ 6,262 $ 5,854
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases were as follows (in thousands): Six Months Ended June 30, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 433 $ 191 Operating cash flows from finance leases 1,010 1,053 Financing cash flows from finance leases 5,992 5,850 Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 144 49,676 Operating leases $ 5 $ 1,212
Schedule of Lease Term and Discount Rate	Lease term and discount rate were as follows: June 30, 2020 December 31, 2019 Weighted-average remaining lease term (years): Finance leases 3.4 3.6 Operating leases 1.8 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 June 30, 2020 are as follows (in thousands): Year Ending Finance Leases Operating Leases 2020 (Remaining six month period) $ 7,047 $ 463 2021 13,680 663 2022 13,883 305 2023 12,523 — Total future lease payments 47,133 1,431 Less: Interest (3,268 ) (58 ) Present value of lease liabilities $ 43,865 $ 1,373

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 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): June 30, 2020 December 31, 2019 Cash $ 198,708 $ 40,715 Money market funds 230,561 85,551 Total cash and cash equivalents $ 429,269 $ 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): June 30, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 225,117 $ 1,062 $ — $ 226,179 Certificates of deposit 30,000 138 — 30,138 Equity investments 125 104 — 229 Total investments $ 255,242 $ 1,304 $ — $ 256,546 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): June 30, 2020 December 31, 2019 Raw materials $ 327 $ 325 Work-in-progress 3,815 2,264 Finished goods 4,440 4,298 Total inventories $ 8,582 $ 6,887
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): June 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 4,429 6,464 Other current assets 2,052 1,717 Total prepaid expenses and other current assets $ 6,481 $ 133,391
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): June 30, 2020 December 31, 2019 Leasehold improvements $ 100,159 $ 101,548 Laboratory equipment 17,362 17,329 Machinery 7,660 8,217 Computer equipment 8,930 8,399 Furniture and fixtures 5,873 5,822 Construction in progress 1,225 1,792 Total property and equipment $ 141,209 $ 143,107 Less: accumulated depreciation (104,225 ) (100,364 ) Property and equipment, net $ 36,984 $ 42,743
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): June 30, 2020 December 31, 2019 Preclinical and clinical trial accruals $ 21,691 $ 16,279 API product price adjustment — 36,324 Payroll and related accruals 14,266 19,784 Property taxes and other 1,145 2,044 Professional services 5,653 4,842 Other 7,709 4,543 Total accrued liabilities $ 50,464 $ 83,816
Schedule of Other Long-term Liabilities	Other long-term liabilities consisted of the following (in thousands): June 30, 2020 December 31, 2019 Accrued long-term co-promotional expenses $ 116,230 $ 53,071 Other long-term tax liabilities 8,653 8,913 Operating lease liabilities, non-current 572 942 Other 1,787 1,340 Total other long-term liabilities $ 127,242 $ 64,266

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Recorded Stock-Based Compensation Expense	Stock-based compensation expense was recorded to research and development and selling, general and administrative expense as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 10,780 $ 10,450 $ 21,417 $ 20,028 Selling, general and administrative 6,864 7,192 13,143 14,044 Total stock-based compensation expense $ 17,644 $ 17,642 $ 34,560 $ 34,072
Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Purchases under 2014 Employee Share Purchase Plan	The assumptions used to estimate the fair value of stock options granted and purchases under the Company’s 2014 Employee Share Purchase Plan (“ESPP”) using the Black-Scholes option valuation model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Stock Options Expected term (in years) 5.5 5.3 5.7 5.3 Expected volatility 69.2 % 68.2 % 68.4 % 67.9 % Risk-free interest rate 0.4 % 2.0 % 0.8 % 2.5 % Expected dividend yield — — — — Weighted average estimated fair value $ 21.72 $ 24.40 $ 17.75 $ 33.20 ESPPs Expected term (in years) 0.5 – 2.0 0.5 – 2.0 0.5 – 2.0 0.5 – 2.0 Expected volatility 49.5 – 77.1 % 48.1 – 62.1 % 49.5 – 77.1 % 48.1 – 62.1 % Risk-free interest rate 0.2 – 2.9 % 1.3 – 2.9 % 0.2 – 2.9 % 1.3 – 2.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 17.82 $ 19.07 $ 18.11 $ 19.65

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Detail) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020USD ($)shares	Jun. 30, 2019shares	Jun. 30, 2020USD ($)Segmentshares	Jun. 30, 2019shares
Accounting Policies [Abstract]
Number of operating segment | Segment			1
Anti-dilutive shares outstanding | shares	9.2	4.4	9	3.4
Currency translation adjustment | $	$ 1.3		$ 1.3
Description of payment term			The period between the transfer control of 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 and for product within one year of 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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income (loss)	$ (85,313)	$ 116,003	$ (163,661)	$ 70,592
Weighted average number of common shares used to calculate net income (loss) per share:
Basic	89,451	86,445	88,835	86,077
Dilutive effect of potential common shares	0	5,283	0	5,992
Diluted	89,451	91,728	88,835	92,069
Net income (loss) per share:
Basic	$ (0.95)	$ 1.34	$ (1.84)	$ 0.82
Diluted	$ (0.95)	$ 1.26	$ (1.84)	$ 0.77

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	6 Months Ended	35 Months Ended	45 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Jun. 30, 2020	Jun. 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	$ 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	$ 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	$ 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 ($) $ in Thousands	Jul. 30, 2013	Apr. 30, 2020	Dec. 31, 2019	Jun. 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	$ 0
AstraZeneca Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price and allocated to performance obligations							$ 50,000
Revenue during period from performance obligations			42,400	400
Unbilled contract asset						$ 50,000
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
Potential milestone payments	875,000
Commercial sales milestone	325,000
Aggregate consideration received				439,000
Unbilled contract asset			50,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	65,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	325,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Deferred Approval Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	160,000
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receipt of development milestone payment					$ 15,000
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
AstraZeneca Agreements [Member] | China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	348,500		22,000
Aggregate consideration received				$ 77,200
Transaction price and allocated to performance obligations			$ 22,000
Proceeds from upfront, non-contingent and non-refundable payments	28,200
Commercial sales and other events milestone	187,500
Estimated joint development extended service period				2024
AstraZeneca Agreements [Member] | China [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	15,000
AstraZeneca Agreements [Member] | China [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 146,000

Collaboration Agreements and _5

Collaboration Agreements and Revenues - Summary of Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 42,888	$ 191,566	$ 67,288	$ 215,429
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	150,581	0	150,581
Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	18,957	40,985	38,402	64,848
Astellas Agreement [Member] | License Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0	0	0
Astellas Agreement [Member] | License Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	117,470	0	117,470
Astellas Agreement [Member] | Development Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	164	369	327	615
Astellas Agreement [Member] | Development Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	4,602	16,854	9,176	21,467
AstraZeneca Agreements [Member] | China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	441	0	594	0
AstraZeneca Agreements [Member] | License Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	33,111	0	33,111
AstraZeneca Agreements [Member] | Development Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 13,750	$ 23,762	$ 28,305	$ 42,766

Collaboration Agreements and _6

Collaboration Agreements and Revenues - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue (Detail) - USD ($) $ in Thousands	Jun. 30, 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	101,482
Deferred Revenue	183
Total Consideration	101,665
Astellas Agreement [Member] | Japan [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	15,458
Deferred Revenue	183
Total Consideration	15,641
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	728,135
Deferred Revenue	2,338
Total Consideration	730,473
Astellas Agreement [Member] | Europe [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	240,184
Deferred Revenue	2,338
Total Consideration	242,522
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	864,100
Deferred Revenue	145,520
Total Consideration	1,009,620
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	521,572
Deferred Revenue	4,547
Total Consideration	526,119
AstraZeneca Agreements [Member] | U.S./RoW and China [Member] | China performance obligation [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	684
Deferred Revenue	140,973
Total Consideration	$ 141,657

Collaboration Agreements and _7

Collaboration Agreements and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail)	3 Months Ended
	Jun. 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	31,700,000
Europe [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	1,600,000
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	90,100,000
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	$ (200,000)

Collaboration Agreements and _8

Collaboration Agreements and Revenues - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 42,888	$ 191,566	$ 67,288	$ 215,429
Non-key Account Hospital Listing Award [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2,600
Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,400		1,700
Product [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	19,833		25,205
Total revenue	15,693	$ 0	20,648	$ 0
Product [Member] | Non-key Account Hospital Listing Award [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(2,566)		(2,566)
Product [Member] | Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(1,372)		(1,748)
Product [Member] | Other Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ (202)		$ (243)

Collaboration Agreements and _9

Collaboration Agreements and Revenues - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 42,888	$ 191,566	$ 67,288	$ 215,429
Non-key Account Hospital Listing Award [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	2,600
Contractual Sales Rebate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 1,400		1,700
Rebates and Discounts [Member] | Gross Accounts Receivable [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			5,600
Rebates and Discounts [Member] | Contract Liabilities [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue			$ 400

Collaboration Agreements and_10

Collaboration Agreements and Revenues - Roll-forward of Contract Liabilities (Detail) $ in Thousands	6 Months Ended
	Jun. 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	(4,907)
Deduction	16
Currency Translation and Other	9
Gross Contract Liabilities Balance	(5,984)
Balance Presented Net Against Accounts Receivable	5,595
Ending balance	$ (389)

Collaboration Agreements and_11

Collaboration Agreements and Revenues - Summary of Contra-Accounts Receivable Items Related to Product Revenue (Detail) - Product [Member] - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	$ 5,724	$ 1,102
Price Adjustment
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	935	936
Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	1,878	148
Non-key Account Hospital Listing Award [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	2,567	0
Other Discounts and Rebates [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	260	18
Provision for Credit Loss [Member]
Disaggregation Of Revenue [Line Items]
Total reductions to gross accounts receivable	$ 84	$ 0

Collaboration Agreements and_12

Collaboration Agreements and Revenues - Drug Product Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 42,888	$ 191,566	$ 67,288	$ 215,429
Astellas Agreement [Member] | Drug Product Revenue [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Drug product revenue recognized	$ 8,200

Collaboration Agreements and_13

Collaboration Agreements and Revenues - Deferred Revenue - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 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	$ 2,700

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 256,546	$ 468,609
U.S. treasury notes and bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	226,179	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	229	255
Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	30,138	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	487,107	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	226,179	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	229	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	230,561	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	30,138	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	406,818	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	176,028	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	229	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	230,561	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	80,289	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	50,151	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	30,138	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	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	$ 1,343	$ 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	$ 1,343	$ 1,544

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 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	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Right-of-use assets - cost	$ 49,903	$ 49,909
Accumulated amortization	(15,535)	(10,307)
Finance lease right-of-use assets, net	34,368	39,602
Right-of-use assets - cost	2,647	2,736
Accumulated amortization	(1,270)	(805)
Operating lease right-of-use assets, net	1,377	1,931
Total lease assets	35,745	41,533
Finance lease liabilities	12,279	12,351
Operating lease liabilities	801	983
Finance lease liabilities	31,586	37,610
Operating lease liabilities	572	942
Total lease liabilities	$ 45,238	$ 51,886

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Finance lease cost:
Amortization of right-of-use assets	$ 2,653	$ 2,571	$ 5,247	$ 5,140
Interest on lease liabilities	534	609	1,049	1,249
Operating lease cost	255	163	564	289
Sublease income	(306)	(237)	(598)	(824)
Total lease cost	$ 3,136	$ 3,106	$ 6,262	$ 5,854

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 433	$ 191
Operating cash flows from finance leases	1,010	1,053
Financing cash flows from finance leases	5,992	5,850
Right-of-use assets obtained in exchange for new lease liabilities:
Finance leases	144	49,676
Operating leases	$ 5	$ 1,212

Leases - Schedule of Lease Term

Leases - Schedule of Lease Term and Discount Rate (Detail)	Jun. 30, 2020	Dec. 31, 2019
Weighted-average remaining lease term (years):
Finance leases	3 years 4 months 24 days	3 years 7 months 6 days
Operating leases	1 year 9 months 18 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	Jun. 30, 2020USD ($)
Finance Leases
2020 (Remaining six month period)	$ 7,047
2021	13,680
2022	13,883
2023	12,523
Total future lease payments	47,133
Less: Interest	(3,268)
Present value of lease liabilities	43,865
Operating Leases
2020 (Remaining six month period)	463
2021	663
2022	305
2023	0
Total future lease payments	1,431
Less: Interest	(58)
Present value of lease liabilities	$ 1,373

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Cash	$ 198,708	$ 40,715
Money market funds	230,561	85,551
Total cash and cash equivalents	$ 429,269	$ 126,266

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail)	Dec. 31, 2019USD ($)Milestone	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Mar. 31, 2020USD ($)
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 126,266,000	$ 429,269,000		$ 429,269,000
Contractual maturities of available-for-sale investments				1 year
Other-than-temporary impairment loss		0	$ 0	$ 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	0		0
Accrued long-term co-promotional expenses	53,071,000	116,230,000		116,230,000
Europe [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets		130,000,000		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		130,000,000
AstraZeneca Agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets							$ 50,000,000
Accrued long-term co-promotional expenses	53,100,000	116,200,000		116,200,000
AstraZeneca Agreements [Member] | Scenario Forecast [Member]
Schedule of Available-for-sale Securities [Line Items]
Accrued long-term co-promotional expenses						$ 82,000,000
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	$ 32,800,000		$ 32,800,000

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 255,242	$ 467,850
Gross Unrealized Holding Gains	1,304	784
Gross Unrealized Holding Losses	0	(25)
Fair Value	256,546	468,609
U.S. treasury notes and bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	225,117	426,995
Gross Unrealized Holding Gains	1,062	536
Gross Unrealized Holding Losses	0	(25)
Fair Value	226,179	427,506
Certificate of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,000	30,000
Gross Unrealized Holding Gains	138	32
Gross Unrealized Holding Losses	0	0
Fair Value	30,138	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	104	130
Gross Unrealized Holding Losses	0	0
Fair Value	$ 229	$ 255

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Investments [Abstract]
Raw materials	$ 327	$ 325
Work-in-progress	3,815	2,264
Finished goods	4,440	4,298
Total inventories	$ 8,582	$ 6,887

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 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	4,429	6,464
Other current assets	2,052	1,717
Total prepaid expenses and other current assets	$ 6,481	$ 133,391

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 141,209	$ 143,107
Less: accumulated depreciation	(104,225)	(100,364)
Property and equipment, net	36,984	42,743
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	100,159	101,548
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	17,362	17,329
Machinery [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	7,660	8,217
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,930	8,399
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	5,873	5,822
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,225	$ 1,792

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 21,691	$ 16,279
API product price adjustment	0	36,324
Payroll and related accruals	14,266	19,784
Property taxes and other	1,145	2,044
Professional services	5,653	4,842
Other	7,709	4,543
Total accrued liabilities	$ 50,464	$ 83,816

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other Liabilities Noncurrent [Abstract]
Accrued long-term co-promotional expenses	$ 116,230	$ 53,071
Other long-term tax liabilities	8,653	8,913
Operating lease liabilities, non-current	572	942
Other	1,787	1,340
Total other long-term liabilities	$ 127,242	$ 64,266

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Recorded Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 17,644	$ 17,642	$ 34,560	$ 34,072
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	10,780	10,450	21,417	20,028
Selling, general and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 6,864	$ 7,192	$ 13,143	$ 14,044

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Purchases under 2014 Employee Share Purchase Plan (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 6 months	5 years 3 months 18 days	5 years 8 months 12 days	5 years 3 months 18 days
Expected volatility	69.20%	68.20%	68.40%	67.90%
Risk-free interest rate	0.40%	2.00%	0.80%	2.50%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 21.72	$ 24.40	$ 17.75	$ 33.20
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	$ 17.82	$ 19.07	$ 18.11	$ 19.65
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	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Accounts receivable from related party	$ 12,090		$ 12,090			$ 4,845
Accrued liabilities to related party	216		216			36,883
Unbilled contract asset	0		0			180,000
Net unbilled contract asset	0		0			125,210
Deferred revenue	0		0			54,790
Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset	130,000		130,000
Astellas Agreement [Member]
Related Party Transaction [Line Items]
Drug product revenue from a related party	8,238	$ 0	8,238	$ 0
Astellas Agreement [Member] | Japan [Member]
Related Party Transaction [Line Items]
Deferred revenue	183		183
Astellas Agreement [Member] | Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset						130,000
Deferred revenue	2,338		2,338
Astellas [Member] | Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset	130,000		130,000
Net unbilled contract asset	0		0			125,200
Deferred revenue	0		0			4,800
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	4,800	134,700	9,500	139,600
Drug product revenue from a related party	8,200		8,200
Expense related to collaboration agreements	200	$ 800	300	$ 1,300
Accounts receivable from related party	12,100		12,100			4,800
Accrued liabilities to related party	$ 200		$ 200			$ 36,900
Astellas [Member] | Astellas Agreement [Member] | Japan [Member]
Related Party Transaction [Line Items]
Accrued liabilities to related party					$ 36,300

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	$ 26.2
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	14.2
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	$ 1.1

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Accrued long-term co-promotional expenses		$ 116,230	$ 53,071
AstraZeneca Agreements [Member]
Subsequent Event [Line Items]
Accrued long-term co-promotional expenses		$ 116,200	$ 53,100
Scenario Forecast [Member] | AstraZeneca Agreements [Member]
Subsequent Event [Line Items]
Accrued long-term co-promotional expenses	$ 82,000