FibroGen (FGEN) 10-Q 7 May 20 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	FGEN
Entity Registrant Name	FIBROGEN, INC.
Entity Central Index Key	0000921299
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity File Number	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		89,104,753

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 121,560	$ 126,266
Short-term investments	413,869	407,491
Accounts receivable, net ($3,723 and $4,845 from a related party)	58,540	28,455
Inventories	8,408	6,887
Prepaid expenses and other current assets ($126,558 and $125,210 from a related party)	134,028	133,391
Total current assets	736,405	702,490
Restricted time deposits	2,072	2,072
Long-term investments	223	61,118
Property and equipment, net	40,058	42,743
Finance lease right-of-use assets	37,017	39,602
Other assets	8,602	9,372
Total assets	824,377	857,397
Current liabilities:
Accounts payable	2,865	6,088
Accrued and other current liabilities ($92 and $36,883 to a related party)	42,309	83,816
Deferred revenue	8,531	490
Finance lease liabilities, current	12,396	12,351
Total current liabilities	66,101	102,745
Long-term portion of lease obligations	1,040	1,141
Product development obligations	16,536	16,780
Deferred revenue, net of current	139,404	99,449
Finance lease liabilities, non-current	34,545	37,610
Other long-term liabilities	89,122	64,266
Total liabilities	346,748	321,991
Commitments and Contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at March 31, 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; 88,896 and 87,657 shares issued and outstanding at March 31, 2020 and December 31, 2019	889	877
Additional paid-in capital	1,319,354	1,300,725
Accumulated other comprehensive income (loss)	1,183	(747)
Accumulated deficit	(863,068)	(784,720)
Total stockholders’ equity	458,358	516,135
Non-controlling interests	19,271	19,271
Total equity	477,629	535,406
Total liabilities, stockholders’ equity and non-controlling interests	$ 824,377	$ 857,397

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Accounts receivable from related party	$ 3,723	$ 4,845
Prepaid expenses and other current assets from related party	126,558	125,210
Accrued and other current liabilities to related party	$ 92	$ 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	88,896,000	87,657,000
Common stock, shares outstanding	88,896,000	87,657,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue:
Total revenue	$ 24,401	$ 23,863
Operating costs and expenses:
Cost of goods sold	$ 970	$ 0
Cost, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember
Research and development	$ 54,902	$ 50,496
Selling, general and administrative	49,603	22,210
Total operating costs and expenses	105,475	72,706
Loss from operations	(81,074)	(48,843)
Interest and other, net
Interest expense	(633)	(770)
Interest income and other, net	3,165	4,177
Total interest and other, net	2,532	3,407
Loss before income taxes	(78,542)	(45,436)
Benefit from income taxes	(194)	(25)
Net loss	$ (78,348)	$ (45,411)
Net loss per share - basic and diluted	$ (0.89)	$ (0.53)
Weighted average number of common shares used to calculate net loss per share - basic and diluted	88,219	85,704
License Revenue [Member]
Revenue:
Total revenue	$ 0	$ 0
Development and Other Revenue [Member]
Revenue:
Total revenue	19,446	23,863
Product Revenue, Net [Member]
Revenue:
Total revenue	$ 4,955	$ 0

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Astellas Agreement [Member]
Collaboration services and other revenue from a related party	$ 4,737	$ 4,859

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (78,348)	$ (45,411)
Other comprehensive income (loss):
Foreign currency translation adjustments	281	291
Available-for-sale investments:
Unrealized gain on investments, net of tax effect	1,649	442
Other comprehensive income, net of taxes	1,930	733
Comprehensive loss	$ (76,418)	$ (44,678)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2018	$ 528,470	$ 854	$ 1,226,453	$ (2,281)	$ (715,827)	$ 19,271
Balance, Shares at Dec. 31, 2018		85,432,102
Impact of change in accounting principle upon adoption | ASU 2016-02 [Member]	8,688	$ 0	0	0	8,688	0
Impact of change in accounting principle upon adoption | ASU 2018-02 [Member]	0	0	0	611	(611)	0
Net loss	(45,411)	0	0	0	(45,411)	0
Change in unrealized gain or loss on investments	442	0	0	442	0	0
Foreign currency translation adjustments	291	0	0	291	0	0
Shares issued from stock plans, net of payroll taxes paid	(416)	$ 7	(423)	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		697,462
Stock-based compensation	16,430	$ 0	16,430	0	0	0
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
Balance at Dec. 31, 2019	535,406	$ 877	1,300,725	(747)	(784,720)	19,271
Balance, Shares at Dec. 31, 2019		87,657,489
Net loss	(78,348)	$ 0	0	0	(78,348)	0
Change in unrealized gain or loss on investments	1,649	0	0	1,649	0	0
Foreign currency translation adjustments	281	0	0	281	0	0
Shares issued from stock plans, net of payroll taxes paid	1,725	$ 12	1,713	0	0	0
Shares issued from stock plans, net of payroll taxes paid, Shares		1,238,141
Stock-based compensation	16,916	$ 0	16,916	0	0	0
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

Condensed Consolidated Statem_5

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (78,348)	$ (45,411)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	2,868	2,744
Amortization of finance lease right-of-use assets	2,594	2,569
Net accretion of discount on investments	(143)	(1,350)
Unrealized loss (gain) on equity investments	21	(51)
Gain on disposal of property and equipment	0	(10)
Stock-based compensation	16,916	16,430
Tax benefit on unrealized gain on available-for-sale securities	(439)	(118)
Realized loss on sales of available-for-sale securities	258	0
Changes in operating assets and liabilities:
Accounts receivable, net	(30,085)	57,661
Inventories	(1,521)	0
Prepaid expenses and other current assets	(637)	(2,785)
Other assets	761	(51)
Accounts payable	(3,223)	(5,367)
Accrued and other liabilities	(41,224)	736
Deferred revenue	47,996	(2,580)
Accrued interest for finance lease liabilities	(216)	219
Other long-term liabilities	24,936	(156)
Net cash provided by (used in) operating activities	(59,486)	22,480
Investing activities
Purchases of property and equipment	(459)	(483)
Purchases of available-for-sale securities and term deposit	(38)	(76,004)
Proceeds from sales of available-for-sale securities	10,606	0
Proceeds from maturities of investments	45,900	50,000
Net cash provided by (used in) investing activities	56,009	(26,487)
Financing activities
Repayments of finance lease liabilities	(2,814)	(3,017)
Repayments of lease obligations	(101)	(101)
Cash paid for payroll taxes on restricted stock unit releases	(5,279)	(5,988)
Proceeds from issuance of common stock	7,004	5,572
Net cash used in financing activities	(1,190)	(3,534)
Effect of exchange rate change on cash and cash equivalents	(39)	(44)
Net decrease in cash and cash equivalents	(4,706)	(7,585)
Total cash and cash equivalents at beginning of period	126,266	89,258
Total cash and cash equivalents at end of period	$ 121,560	$ 81,673

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 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 with the European Medicines Agency (“EMA”) is expected in the second quarter of 2020 for CKD in both dialysis and non-dialysis. 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 (“MDS”). 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 (“IPF”) and pancreatic cancer. Pamrevlumab is also currently in a Phase 2 trial for Duchenne muscular dystrophy (“DMD”). 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 China”). 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 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 Loss per Share Diluted weighted average shares did not include 8.7 million and 9.5 million securities for the three months March 31, 2020 and 2019, as they were anti-dilutive. Risks and Uncertainties The Company’s business is subject to risks and uncertainties, including those related to the severe acute respiratory syndrome coronavirus 2 and the associated disease (“COVID-19”) and the related shelter-in-place, stay-at-home and other similar governmental orders issued in response to the COVID-19 pandemic. 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 . Recently Issued and Adopted Accounting Guidance In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Codification Improvements to Topic 326, Financial Instruments-Credit Losses , Recently Issued Accounting Guidance Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes Significant Accounting Policies The accounting policies used by the Company in its presentation of interim financial results are consistent with those presented in Note 2 to the consolidated financial statements included in the 2019 Form 10-K, except for the following: 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 months ended March 31, 2020 and the allowance for doubtful accounts as of March 31, 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.

Collaboration Agreements

Collaboration Agreements	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements	2. Collaboration Agreements Astellas Agreements Japan Agreement In June 2005, the Company entered into a collaboration agreement with Astellas for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). Under the Japan Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $132.5 million in potential milestone payments, comprised of (i) up to $22.5 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of July 2016), (ii) up to $95.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $15.0 million in milestone payments upon the achievement of specified commercial sales milestone. The Japan Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range after commercial launch. The aggregate amount of consideration received through March 31, 2020 totals $90.1 million. Europe Agreement In April 2006, the Company entered into a separate collaboration agreement with Astellas for the development and commercialization of roxadustat for the treatment of anemia in Europe, the Middle East, the Commonwealth of Independent States and South Africa (“Europe Agreement”). Under the terms of the Europe Agreement, Astellas paid license fees and other upfront consideration totaling $320.0 million (such amounts were fully received as of February 2009). The Europe Agreement also provides for additional development and regulatory approval milestone payments up to $425.0 million, comprised of (i) up to $90.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of 2012), (ii) up to $335.0 million in milestone payments upon achievement of specified regulatory milestone events. Under the Europe Agreement, Astellas committed to fund 50% of joint development costs for Europe and North America, and all territory-specific costs. The Europe Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range. The aggregate amount of consideration received through March 31, 2020 totals $410.0 million. During the second quarter of 2019, the Company received positive topline results from analyses of pooled major adverse cardiac event (“MACE”) and MACE+ 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 $0.3 million was recognized as revenue during the three months ended March 31, 2020, from performance obligations satisfied or partially satisfied. According to the Europe Agreement, these milestone payments are not billable to Astellas until the submission of an MAA, which is expected in the second quarter of 2020. Therefore this $130.0 million remained as an unbilled contract asset as of March 31, 2020. 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 March 31, 2020 totals $389.0 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 $0.2 million was recognized as revenue during the three months ended March 31, 2020, from performance obligations satisfied or partially satisfied. The Company submitted such NDA in December 2019, which was accepted by the FDA for review in February 2020. According to the U.S/RoW Agreement, this milestone payment is billable to AstraZeneca when the NDA is accepted by the FDA. Therefore this $50.0 million was billed during the first quarter of 2020, the payment of which was fully received in April 2020. 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 March 31, 2020 totals $77.2 million. In December 2019, roxadustat was included on the updated National Reimbursement Drug List (“NRDL”) released by China’s National Healthcare Security Administration (“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 (“CIA”) 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 (“ACI”) and multiple myeloma (“MM”) 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 CIA, ACI and MM under the AstraZeneca agreements is estimated to continue through the end of 2024, to allow for development of these additional indications. 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 March 31, Agreement Performance Obligation 2020 2019 Japan License revenue $ — $ — Development revenue $ 163 $ 246 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 March 31, 2020 Deferred Revenue at March 31, 2020 Total Consideration Through March 31, 2020 License $ 86,024 $ — $ 86,024 Development revenue 15,293 269 15,562 Total license and development revenue $ 101,317 $ 269 $ 101,586 The revenue recognized under the Japan Agreement for the three months ended March 31, 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 March 31, Agreement Performance Obligation 2020 2019 Europe License revenue $ — $ — Development revenue $ 4,574 $ 4,613 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 March 31, 2020 Deferred Revenue at March 31, 2020 Total Consideration Through March 31, 2020 License $ 487,951 $ — $ 487,951 Development revenue 235,582 3,442 239,024 Total license and development revenue $ 723,533 $ 3,442 * $ 726,975 _______________________________________________________________________________________________________ * Contract assets and liabilities related to rights and obligations in the same contract are recorded net on the condensed consolidated balance sheets. As of March 31, 2020, prepaid expenses and other current assets included a net unbilled contract asset of $126.6 million related to the Europe Agreement, which represents the net of the above-mentioned unbilled contract asset of $130.0 million, and $3.4 million of deferred revenue presented above. The revenue recognized under the Europe Agreement for the three months ended March 31, 2020 included an increase in revenue of $0.9 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 $38.2 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 March 31, Agreement Performance Obligation 2020 2019 U.S. / RoW and China License revenue $ — $ — Development revenue 14,556 19,004 China performance obligation $ 153 $ — 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 March 31, 2020 Deferred Revenue at March 31, 2020 Total Consideration Through March 31, 2020 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 507,822 6,323 514,145 China performance obligation 243 141,079 141,322 Total license and development revenue $ 849,909 $ 147,402 $ 997,311 The revenue recognized under the U.S./RoW Agreement for the three months ended March 31, 2020 included an insignificant decrease 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 $115.3 million of variable consideration from estimated future co-development billing and is expected to be recognized over the remaining development service period, except for amounts allocated to the China performance obligation, which are expected to be recognized in a pattern consistent with estimated deliveries of the commercial drug product. Product Revenue, Net The Company started commercial sales of roxadustat drug product in China in the third quarter of 2019. Drug 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 price adjustment, contractual sales rebate and other discounts. Product revenue, net was as follows (in thousands): Three Months Ended March 31, 2020 Gross revenue $ 5,372 Contractual sales rebate (376 ) Key account hospital sales rebate (27 ) Transfer fee discount (14 ) Product revenue, net $ 4,955 For the three months ended March 31, 2020, the contractual sales rebate was $0.4 million, which was 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 including sales return allowance were immaterial for the period. The following table is a roll-forward of accounts receivable allowances related to product revenue: Balance at December 31, 2019 Current Period Additions Credits / Payments Balance at March 31, 2020 Price adjustment $ 936 $ — $ — $ 936 Contractual sales rebate 148 376 — 524 Key account hospital sales rebate 12 27 — 39 Transfer fee discount 6 14 — 20 Total $ 1,102 $ 417 $ — $ 1,519 The above contractual allowances are recorded as reductions of the gross accounts receivable from the distributor in the same period that the related revenue is recorded, and applied to future sales orders made by the distributor under the Company’s discretion. 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 March 31, 2020, approximately $1.7 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, as a result of the transfer of control of commercial drug product in China.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 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): March 31, 2020 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 303,265 $ 80,489 $ — $ 383,754 Equity investments 223 — — 223 Money market funds 72,148 — — 72,148 Certificate of deposit — 30,115 — 30,115 Total $ 375,636 $ 110,604 $ — $ 486,240 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): March 31, 2020 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,443 $ 1,443 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	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	4. Leases The Company’s lease assets and related lease liabilities were as follows (in thousands): Balance Sheet Line Item March 31, 2020 December 31, 2019 Assets Finance: Right-of-use assets - cost $ 49,918 $ 49,909 Accumulated amortization (12,901 ) (10,307 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 37,017 39,602 Operating: Right-of-use assets - cost 2,736 2,736 Accumulated amortization (1,078 ) (805 ) Operating lease right-of-use assets, net Other assets 1,658 1,931 Total lease assets $ 38,675 $ 41,533 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 12,396 $ 12,351 Operating lease liabilities Accrued and other current liabilities 900 983 Non-current: Finance lease liabilities Finance lease liabilities, non-current 34,545 37,610 Operating lease liabilities Other long-term liabilities 678 942 Total lease liabilities $ 48,519 $ 51,886 The components of lease expense were as follows (in thousands): Three Months Ended March 31, Statement of Operations Line Item 2020 2019 Finance lease cost: Amortization of right-of-use assets Cost of goods sold; Research and development; Selling, general and administrative expenses $ 2,594 $ 2,569 Interest on lease liabilities Interest expense 515 640 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 309 126 Sublease income Selling, general and administrative expenses (292 ) (588 ) Total lease cost $ 3,126 $ 2,747 Supplemental cash flow information related to leases were as follows (in thousands): Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 149 $ 99 Operating cash flows from finance leases 517 435 Financing cash flows from finance leases 2,814 3,017 Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 9 49,598 Operating leases $ — $ 730 Lease term and discount rate were as follows: March 31, 2020 December 31, 2019 Weighted-average remaining lease term (years): Finance leases 3.4 3.6 Operating leases 1.9 2.1 Weighted-average discount rate: Finance leases 4.42 % 4.42 % Operating leases 4.75 % 4.75 % Maturities of lease liabilities as of March 31, 2020 are as follows (in thousands): Year Ending Finance Leases Operating Leases 2020 (Remaining nine month period) $ 10,535 $ 689 2021 13,680 657 2022 13,883 302 2023 12,523 — Total future lease payments 50,621 1,648 Less: Interest (3,680 ) (70 ) Present value of lease liabilities $ 46,941 $ 1,578

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 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): March 31, 2020 December 31, 2019 Cash $ 49,412 $ 40,715 Money market funds 72,148 85,551 Total cash and cash equivalents $ 121,560 $ 126,266 At March 31, 2020 and December 31, 2019, a total of $29.8 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): March 31, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 381,238 $ 2,516 $ — $ 383,754 Certificates of deposit 30,000 115 — 30,115 Equity investments 125 98 — 223 Total investments $ 411,363 $ 2,729 $ — $ 414,092 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 March 31, 2020, all of the available-for-sale investments had contractual maturities within one year. During the three months ended March 31, 2020, the Company did not recognize any other-than-temporary impairment loss. Inventories Inventories consisted of the following (in thousands): March 31, 2020 December 31, 2019 Raw materials $ 459 $ 325 Work-in-progress 2,948 2,264 Finished goods 5,001 4,298 Total inventories $ 8,408 $ 6,887 The provision to write-down excess and obsolete inventory was nominal for the three months ended March 31, 2020. Prepaid expenses and other current assets Prepaid expenses and other current assets consisted of the following (in thousands): March 31, 2020 December 31, 2019 Unbilled contract assets $ 130,000 $ 180,000 Deferred revenues from associated contracts (3,442 ) (54,790 ) Net unbilled contract assets 126,558 125,210 Prepaid assets 5,267 6,464 Other current assets 2,203 1,717 Total prepaid expenses and other current assets $ 134,028 $ 133,391 The unbilled contract assets as of March 31, 2020 were related to two regulatory milestones totaling $130.0 million under the Europe Agreement with Astellas associated with the planned MAA submission in Europe. 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, and recorded as accounts receivable as of March 31, 2020. See Note 2 for details. Property and Equipment Property and equipment consisted of the following (in thousands): March 31, 2020 December 31, 2019 Leasehold improvements $ 101,721 $ 101,548 Laboratory equipment 17,359 17,329 Machinery 8,229 8,217 Computer equipment 8,879 8,399 Furniture and fixtures 5,883 5,822 Construction in progress 1,212 1,792 Total property and equipment $ 143,283 $ 143,107 Less: accumulated depreciation (103,225 ) (100,364 ) Property and equipment, net $ 40,058 $ 42,743 Accrued Liabilities Accrued liabilities consisted of the following (in thousands): March 31, 2020 December 31, 2019 Preclinical and clinical trial accruals $ 16,704 $ 16,279 API product price adjustment — 36,324 Payroll and related accruals 11,899 19,784 Property taxes and other 4,033 2,044 Professional services 4,608 4,842 Other 5,065 4,543 Total accrued liabilities $ 42,309 $ 83,816 The amount of $36.3 million accrued as of December 31, 2019 was related to the change in estimated variable consideration of active pharmaceutical ingredient (“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): March 31, 2020 December 31, 2019 Accrued long-term co-promotional expenses $ 78,301 $ 53,071 Other long-term tax liabilities 8,786 8,913 Operating lease liabilities, non-current 678 942 Other 1,357 1,340 Total other long-term liabilities $ 89,122 $ 64,266 The accrued long-term co-promotional expenses of $78.3 million and $53.1 million as of March 31, 2020 and December 31, 2019, respectively, were related to the estimated amount payable to AstraZeneca for its sales and marketing efforts related to the commercial launch for roxadustat in China. The payment for such amount is not expected to occur within the next year.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	6. Stock-Based Compensation Stock-based compensation expense was allocated to research and development and selling, general and administrative expense as follows (in thousands): Three Months Ended March 31, 2020 2019 Research and development $ 10,637 $ 9,578 Selling, general and administrative 6,279 6,852 Total stock-based compensation expense $ 16,916 $ 16,430 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 March 31, 2020 2019 Stock Options Expected term (in years) 5.7 5.3 Expected volatility 68.3 % 67.9 % Risk-free interest rate 0.9 % 2.6 % Expected dividend yield — — Weighted average estimated fair value $ 17.24 $ 34.14 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 Expected volatility 49.5 - 57.7 % 48.1 - 62.1 % Risk-free interest rate 1.5 - 2.9 % 1.3 - 2.9 % Expected dividend yield — — Weighted average estimated fair value $ 18.57 $ 20.57

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes The benefits from income taxes for the three months ended March 31, 2020 and 2019 were primarily due to the tax effect arising from other comprehensive income related to available-for-sale securities, partially offset by foreign taxes. On March 27, 2020, the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) was enacted and signed into law. The CARES Act includes changes to the tax provisions that benefits business entities, and makes certain technical corrections to the 2017 Tax Cuts and Jobs Act. U.S. GAAP requires recognition of the tax effects of new legislation during the reporting period that includes the enactment date. The Company evaluated and determined that the impact is immaterial. 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	3 Months Ended
	Mar. 31, 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 $4.7 million and $4.9 million for the three months ended March 31, 2020 and 2019, respectively. The Company recorded expense related to collaboration agreements with Astellas of $0.1 million and $0.5 million during the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020 and December 31, 2019, accounts receivable from Astellas were $3.7 million and $4.8 million, respectively, and amounts due to Astellas were $0.1 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 March 31, 2020 and December 31, 2019 included $126.6 and $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 $3.4 million and $4.8 million of associated deferred revenue. See Note 2 for details. According to the Europe Agreement, this $130.0 million is not billable to Astellas until the submission of an MAA, therefore the net contract asset was included in the prepaid expenses and other current assets line on the Company’s consolidated balance sheet.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Contract Obligations As of March 31, 2020, the Company had outstanding total non-cancelable contract obligations of $23.5 million, including $11.9 million for manufacture and supply of roxadustat, $11.0 million for future milestone payments for research and pre-clinical stage development programs, and $0.6 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 The Company is a party to various legal actions that arose in the ordinary course of its business. The Company did not have any material accruals for any currently active legal action in its consolidated balance sheets as of March 31, 2020, as it could not predict the ultimate outcome of these matters, or reasonably estimate the potential exposure. Indemnification Agreements The Company enters into standard indemnification arrangements in the ordinary course of business, including for example, service, manufacturing and collaboration agreements. Pursuant to these arrangements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, including in connection with intellectual property infringement claims by any third party with respect to its technology. The term of these indemnification agreements is generally perpetual any time after the execution of the agreement. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the extent permissible under applicable law. The maximum potential amount of future payments the Company could be required to make under these arrangements is not determinable. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, the Company believes the estimated fair value of these arrangements is minimal.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 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 with the European Medicines Agency (“EMA”) is expected in the second quarter of 2020 for CKD in both dialysis and non-dialysis. 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 (“MDS”). 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 (“IPF”) and pancreatic cancer. Pamrevlumab is also currently in a Phase 2 trial for Duchenne muscular dystrophy (“DMD”).
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 China”). 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 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 Loss Per Share	Net Loss per Share Diluted weighted average shares did not include 8.7 million and 9.5 million securities for the three months March 31, 2020 and 2019, as they were anti-dilutive.
Risks and Uncertainties	Risks and Uncertainties The Company’s business is subject to risks and uncertainties, including those related to the severe acute respiratory syndrome coronavirus 2 and the associated disease (“COVID-19”) and the related shelter-in-place, stay-at-home and other similar governmental orders issued in response to the COVID-19 pandemic. 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 .
Recently Issued and Adopted Accounting Guidance	Recently Issued and Adopted Accounting Guidance In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Codification Improvements to Topic 326, Financial Instruments-Credit Losses ,
Recently Issued Accounting Guidance Not Yet Adopted	Recently Issued Accounting Guidance Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes Significant Accounting Policies The accounting policies used by the Company in its presentation of interim financial results are consistent with those presented in Note 2 to the consolidated financial statements included in the 2019 Form 10-K, except for the following: 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 months ended March 31, 2020 and the allowance for doubtful accounts as of March 31, 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.
Collaboration Arrangements	Astellas Agreements Japan Agreement In June 2005, the Company entered into a collaboration agreement with Astellas for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). Under the Japan Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $132.5 million in potential milestone payments, comprised of (i) up to $22.5 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of July 2016), (ii) up to $95.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $15.0 million in milestone payments upon the achievement of specified commercial sales milestone. The Japan Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range after commercial launch. The aggregate amount of consideration received through March 31, 2020 totals $90.1 million. Europe Agreement In April 2006, the Company entered into a separate collaboration agreement with Astellas for the development and commercialization of roxadustat for the treatment of anemia in Europe, the Middle East, the Commonwealth of Independent States and South Africa (“Europe Agreement”). Under the terms of the Europe Agreement, Astellas paid license fees and other upfront consideration totaling $320.0 million (such amounts were fully received as of February 2009). The Europe Agreement also provides for additional development and regulatory approval milestone payments up to $425.0 million, comprised of (i) up to $90.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of 2012), (ii) up to $335.0 million in milestone payments upon achievement of specified regulatory milestone events. Under the Europe Agreement, Astellas committed to fund 50% of joint development costs for Europe and North America, and all territory-specific costs. The Europe Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range. The aggregate amount of consideration received through March 31, 2020 totals $410.0 million. During the second quarter of 2019, the Company received positive topline results from analyses of pooled major adverse cardiac event (“MACE”) and MACE+ 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 $0.3 million was recognized as revenue during the three months ended March 31, 2020, from performance obligations satisfied or partially satisfied. According to the Europe Agreement, these milestone payments are not billable to Astellas until the submission of an MAA, which is expected in the second quarter of 2020. Therefore this $130.0 million remained as an unbilled contract asset as of March 31, 2020. 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 March 31, 2020 totals $389.0 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 $0.2 million was recognized as revenue during the three months ended March 31, 2020, from performance obligations satisfied or partially satisfied. The Company submitted such NDA in December 2019, which was accepted by the FDA for review in February 2020. According to the U.S/RoW Agreement, this milestone payment is billable to AstraZeneca when the NDA is accepted by the FDA. Therefore this $50.0 million was billed during the first quarter of 2020, the payment of which was fully received in April 2020. 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 March 31, 2020 totals $77.2 million. In December 2019, roxadustat was included on the updated National Reimbursement Drug List (“NRDL”) released by China’s National Healthcare Security Administration (“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 (“CIA”) 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 (“ACI”) and multiple myeloma (“MM”) 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 CIA, ACI and MM under the AstraZeneca agreements is estimated to continue through the end of 2024, to allow for development of these additional indications.
Product Revenue	Product Revenue, Net The Company started commercial sales of roxadustat drug product in China in the third quarter of 2019. Drug 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 price adjustment, contractual sales rebate and other discounts. Product revenue, net was as follows (in thousands): Three Months Ended March 31, 2020 Gross revenue $ 5,372 Contractual sales rebate (376 ) Key account hospital sales rebate (27 ) Transfer fee discount (14 ) Product revenue, net $ 4,955 For the three months ended March 31, 2020, the contractual sales rebate was $0.4 million, which was 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 including sales return allowance were immaterial for the period. The following table is a roll-forward of accounts receivable allowances related to product revenue: Balance at December 31, 2019 Current Period Additions Credits / Payments Balance at March 31, 2020 Price adjustment $ 936 $ — $ — $ 936 Contractual sales rebate 148 376 — 524 Key account hospital sales rebate 12 27 — 39 Transfer fee discount 6 14 — 20 Total $ 1,102 $ 417 $ — $ 1,519
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 March 31, 2020, approximately $1.7 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, as a result of the transfer of control of commercial drug product in China.

Collaboration Agreements (Table

Collaboration Agreements (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2020 Gross revenue $ 5,372 Contractual sales rebate (376 ) Key account hospital sales rebate (27 ) Transfer fee discount (14 ) Product revenue, net $ 4,955
Summary of Accounts Receivable Allowances Related to Product Revenue	The following table is a roll-forward of accounts receivable allowances related to product revenue: Balance at December 31, 2019 Current Period Additions Credits / Payments Balance at March 31, 2020 Price adjustment $ 936 $ — $ — $ 936 Contractual sales rebate 148 376 — 524 Key account hospital sales rebate 12 27 — 39 Transfer fee discount 6 14 — 20 Total $ 1,102 $ 417 $ — $ 1,519
Japan [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Japan Agreement were as follows (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2020 2019 Japan License revenue $ — $ — Development revenue $ 163 $ 246
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 March 31, 2020 Deferred Revenue at March 31, 2020 Total Consideration Through March 31, 2020 License $ 86,024 $ — $ 86,024 Development revenue 15,293 269 15,562 Total license and development revenue $ 101,317 $ 269 $ 101,586
Europe [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended March 31, Agreement Performance Obligation 2020 2019 Europe License revenue $ — $ — Development revenue $ 4,574 $ 4,613
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 March 31, 2020 Deferred Revenue at March 31, 2020 Total Consideration Through March 31, 2020 License $ 487,951 $ — $ 487,951 Development revenue 235,582 3,442 239,024 Total license and development revenue $ 723,533 $ 3,442 * $ 726,975 _______________________________________________________________________________________________________ * Contract assets and liabilities related to rights and obligations in the same contract are recorded net on the condensed consolidated balance sheets. As of March 31, 2020, prepaid expenses and other current assets included a net unbilled contract asset of $126.6 million related to the Europe Agreement, which represents the net of the above-mentioned unbilled contract asset of $130.0 million, and $3.4 million of deferred revenue presented above.
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 March 31, Agreement Performance Obligation 2020 2019 U.S. / RoW and China License revenue $ — $ — Development revenue 14,556 19,004 China performance obligation $ 153 $ —
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 March 31, 2020 Deferred Revenue at March 31, 2020 Total Consideration Through March 31, 2020 License $ 341,844 $ — $ 341,844 Co-development, information sharing & committee services 507,822 6,323 514,145 China performance obligation 243 141,079 141,322 Total license and development revenue $ 849,909 $ 147,402 $ 997,311

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 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): March 31, 2020 Level 1 Level 2 Level 3 Total U.S. treasury notes and bills $ 303,265 $ 80,489 $ — $ 383,754 Equity investments 223 — — 223 Money market funds 72,148 — — 72,148 Certificate of deposit — 30,115 — 30,115 Total $ 375,636 $ 110,604 $ — $ 486,240 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): March 31, 2020 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,443 $ 1,443 December 31, 2019 Level 1 Level 2 Level 3 Total Lease obligations $ — $ — $ 1,544 $ 1,544

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2020 December 31, 2019 Assets Finance: Right-of-use assets - cost $ 49,918 $ 49,909 Accumulated amortization (12,901 ) (10,307 ) Finance lease right-of-use assets, net Finance lease right-of-use assets 37,017 39,602 Operating: Right-of-use assets - cost 2,736 2,736 Accumulated amortization (1,078 ) (805 ) Operating lease right-of-use assets, net Other assets 1,658 1,931 Total lease assets $ 38,675 $ 41,533 Liabilities Current: Finance lease liabilities Finance lease liabilities, current $ 12,396 $ 12,351 Operating lease liabilities Accrued and other current liabilities 900 983 Non-current: Finance lease liabilities Finance lease liabilities, non-current 34,545 37,610 Operating lease liabilities Other long-term liabilities 678 942 Total lease liabilities $ 48,519 $ 51,886
Components of Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended March 31, Statement of Operations Line Item 2020 2019 Finance lease cost: Amortization of right-of-use assets Cost of goods sold; Research and development; Selling, general and administrative expenses $ 2,594 $ 2,569 Interest on lease liabilities Interest expense 515 640 Operating lease cost Cost of goods sold; Research and development; Selling, general and administrative expenses 309 126 Sublease income Selling, general and administrative expenses (292 ) (588 ) Total lease cost $ 3,126 $ 2,747
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases were as follows (in thousands): Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 149 $ 99 Operating cash flows from finance leases 517 435 Financing cash flows from finance leases 2,814 3,017 Right-of-use assets obtained in exchange for new lease liabilities: Finance leases 9 49,598 Operating leases $ — $ 730
Schedule of Lease Term and Discount Rate	Lease term and discount rate were as follows: March 31, 2020 December 31, 2019 Weighted-average remaining lease term (years): Finance leases 3.4 3.6 Operating leases 1.9 2.1 Weighted-average discount rate: Finance leases 4.42 % 4.42 % Operating leases 4.75 % 4.75 %
Schedule of Maturities of Finance and Operating Leases Liabilities	Maturities of lease liabilities as of March 31, 2020 are as follows (in thousands): Year Ending Finance Leases Operating Leases 2020 (Remaining nine month period) $ 10,535 $ 689 2021 13,680 657 2022 13,883 302 2023 12,523 — Total future lease payments 50,621 1,648 Less: Interest (3,680 ) (70 ) Present value of lease liabilities $ 46,941 $ 1,578

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 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): March 31, 2020 December 31, 2019 Cash $ 49,412 $ 40,715 Money market funds 72,148 85,551 Total cash and cash equivalents $ 121,560 $ 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): March 31, 2020 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value U.S. treasury notes and bills $ 381,238 $ 2,516 $ — $ 383,754 Certificates of deposit 30,000 115 — 30,115 Equity investments 125 98 — 223 Total investments $ 411,363 $ 2,729 $ — $ 414,092 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): March 31, 2020 December 31, 2019 Raw materials $ 459 $ 325 Work-in-progress 2,948 2,264 Finished goods 5,001 4,298 Total inventories $ 8,408 $ 6,887
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): March 31, 2020 December 31, 2019 Unbilled contract assets $ 130,000 $ 180,000 Deferred revenues from associated contracts (3,442 ) (54,790 ) Net unbilled contract assets 126,558 125,210 Prepaid assets 5,267 6,464 Other current assets 2,203 1,717 Total prepaid expenses and other current assets $ 134,028 $ 133,391
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): March 31, 2020 December 31, 2019 Leasehold improvements $ 101,721 $ 101,548 Laboratory equipment 17,359 17,329 Machinery 8,229 8,217 Computer equipment 8,879 8,399 Furniture and fixtures 5,883 5,822 Construction in progress 1,212 1,792 Total property and equipment $ 143,283 $ 143,107 Less: accumulated depreciation (103,225 ) (100,364 ) Property and equipment, net $ 40,058 $ 42,743
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): March 31, 2020 December 31, 2019 Preclinical and clinical trial accruals $ 16,704 $ 16,279 API product price adjustment — 36,324 Payroll and related accruals 11,899 19,784 Property taxes and other 4,033 2,044 Professional services 4,608 4,842 Other 5,065 4,543 Total accrued liabilities $ 42,309 $ 83,816
Schedule of Other Long-term Liabilities	Other long-term liabilities consisted of the following (in thousands): March 31, 2020 December 31, 2019 Accrued long-term co-promotional expenses $ 78,301 $ 53,071 Other long-term tax liabilities 8,786 8,913 Operating lease liabilities, non-current 678 942 Other 1,357 1,340 Total other long-term liabilities $ 89,122 $ 64,266

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Allocated Stock-Based Compensation Expense	Stock-based compensation expense was allocated to research and development and selling, general and administrative expense as follows (in thousands): Three Months Ended March 31, 2020 2019 Research and development $ 10,637 $ 9,578 Selling, general and administrative 6,279 6,852 Total stock-based compensation expense $ 16,916 $ 16,430
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 March 31, 2020 2019 Stock Options Expected term (in years) 5.7 5.3 Expected volatility 68.3 % 67.9 % Risk-free interest rate 0.9 % 2.6 % Expected dividend yield — — Weighted average estimated fair value $ 17.24 $ 34.14 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 Expected volatility 49.5 - 57.7 % 48.1 - 62.1 % Risk-free interest rate 1.5 - 2.9 % 1.3 - 2.9 % Expected dividend yield — — Weighted average estimated fair value $ 18.57 $ 20.57

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail) shares in Millions	3 Months Ended
	Mar. 31, 2020Segmentshares	Mar. 31, 2019shares
Accounting Policies [Abstract]
Number of operating segment | Segment	1
Anti-dilutive shares outstanding | shares	8.7	9.5

Collaboration Agreements - Aste

Collaboration Agreements - Astellas Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended	35 Months Ended	45 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Mar. 31, 2020	Feb. 28, 2009	Feb. 28, 2009	Dec. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled contract asset			$ 130,000,000			$ 180,000,000
Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled contract asset			$ 130,000,000
Astellas Agreement [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received					$ 40,100,000
Potential milestone payments		$ 132,500,000
Commercial sales milestone		15,000,000
Additional consideration based on net sales description			low 20% range
Aggregate consideration received			$ 90,100
Astellas Agreement [Member] | Japan [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		22,500,000
Astellas Agreement [Member] | Japan [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments		$ 95,000,000
Astellas Agreement [Member] | Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront, non-contingent and time-based payments received				$ 320,000,000
Additional consideration based on net sales description			low 20% range
Aggregate consideration received			$ 410,000,000
Development and regulatory approval milestones	$ 425,000,000
Percentage of joint development costs committed to fund	50.00%
Transaction price and allocated to performance obligations			130,000,000
Unbilled contract asset			130,000,000
Revenue during period from performance obligations			$ 300,000			$ 128,800,000
Astellas Agreement [Member] | Europe [Member] | Clinical and Development Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 90,000,000
Astellas Agreement [Member] | Europe [Member] | Regulatory Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments	$ 335,000,000

Collaboration Agreements - Astr

Collaboration Agreements - AstraZeneca Agreements - Additional Information 1 (Detail) - USD ($) $ in Thousands	Jul. 30, 2013	Apr. 30, 2020	Dec. 31, 2019	Mar. 31, 2020	Dec. 31, 2015	Jun. 30, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled contract asset			$ 180,000	$ 130,000
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	200
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				389,000
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] | Subsequent Event [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
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
Milestone payment, revenue recognition				$ 0
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 - Summ

Collaboration Agreements - Summary of Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 24,401	$ 23,863
License Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	19,446	23,863
Astellas Agreement [Member] | License Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
Astellas Agreement [Member] | License Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
Astellas Agreement [Member] | Development Revenue [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	163	246
Astellas Agreement [Member] | Development Revenue [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	4,574	4,613
AstraZeneca Agreements [Member] | China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	153	0
AstraZeneca Agreements [Member] | License Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	0	0
AstraZeneca Agreements [Member] | Development Revenue [Member] | U.S./RoW and China [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total revenue	$ 14,556	$ 19,004

Collaboration Agreements - Tran

Collaboration Agreements - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue	$ 3,442	$ 54,790
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	101,317
Deferred Revenue	269
Total Consideration	101,586
Astellas Agreement [Member] | Japan [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	15,293
Deferred Revenue	269
Total Consideration	15,562
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	723,533
Deferred Revenue	3,442
Total Consideration	726,975
Astellas Agreement [Member] | Europe [Member] | Development Revenue [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	235,582
Deferred Revenue	3,442
Total Consideration	239,024
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	849,909
Deferred Revenue	147,402
Total Consideration	997,311
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	507,822
Deferred Revenue	6,323
Total Consideration	514,145
AstraZeneca Agreements [Member] | U.S./RoW and China [Member] | China performance obligation [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	243
Deferred Revenue	141,079
Total Consideration	$ 141,322

Collaboration Agreements - Su_2

Collaboration Agreements - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail)	3 Months Ended
	Mar. 31, 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	38,200,000
Europe [Member] | Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Changes in revenue due to prior period adjustment of performance obligations	900,000
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	$ 115,300,000

Collaboration Agreements - Tr_2

Collaboration Agreements - Transaction Price Related to Consideration Received and Accounts Receivable Allocated to Performance Obligations along with Associated Deferred Revenue (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Unbilled contract asset	$ 130,000	$ 180,000
Deferred revenue	3,442	54,790
Net unbilled contract asset	126,558	$ 125,210
Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Unbilled contract asset	130,000
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Unbilled contract asset	130,000
Deferred revenue	3,442
Astellas Agreement [Member] | Europe [Member] | Prepaid Expenses and Other Current Assets [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Net unbilled contract asset	$ 126,600

Collaboration Agreements - Su_3

Collaboration Agreements - Summary of Product Revenue, Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 24,401	$ 23,863
Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	400
Product [Member]
Disaggregation Of Revenue [Line Items]
Gross revenue	5,372
Total revenue	4,955	$ 0
Product [Member] | Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(376)
Product [Member] | Key Account Hospital Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	(27)
Product [Member] | Transfer Fee Discount [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ (14)

Collaboration Agreements - Prod

Collaboration Agreements - Product Revenue, Net - Additional Information 1 (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 24,401	$ 23,863
Contractual Sales Rebate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenue	$ 400

Collaboration Agreements - Su_4

Collaboration Agreements - Summary of Accounts Receivable Allowances Related to Product Revenue (Detail) - Product [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	$ 1,102
Current Period Additions	417
Credits / Payments	0
Balance at March 31, 2020	1,519
Price Adjustment
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	936
Current Period Additions	0
Credits / Payments	0
Balance at March 31, 2020	936
Contractual Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	148
Current Period Additions	376
Credits / Payments	0
Balance at March 31, 2020	524
Key Account Hospital Sales Rebate [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	12
Current Period Additions	27
Credits / Payments	0
Balance at March 31, 2020	39
Transfer Fee Discount [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	6
Current Period Additions	14
Credits / Payments	0
Balance at March 31, 2020	$ 20

Collaboration Agreements - Defe

Collaboration Agreements - Deferred Revenue - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Contract with Customer, Liability [Abstract]
Deferred revenue	$ 3,442	$ 54,790
AstraZeneca Agreements [Member] | China [Member]
Contract with Customer, Liability [Abstract]
Deferred revenue	$ 1,700

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 414,092	$ 468,609
U.S. treasury notes and bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	383,754	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	223	255
Certificate of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	30,115	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	486,240	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	383,754	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	223	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	72,148	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	30,115	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	375,636	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	303,265	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	223	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	72,148	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	110,604	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	80,489	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	30,115	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	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	$ 1,443	$ 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	$ 1,443	$ 1,544

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 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	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Right-of-use assets - cost	$ 49,918	$ 49,909
Accumulated amortization	(12,901)	(10,307)
Finance lease right-of-use assets, net	37,017	39,602
Right-of-use assets - cost	2,736	2,736
Accumulated amortization	(1,078)	(805)
Operating lease right-of-use assets, net	1,658	1,931
Total lease assets	38,675	41,533
Finance lease liabilities	12,396	12,351
Operating lease liabilities	900	983
Finance lease liabilities	34,545	37,610
Operating lease liabilities	678	942
Total lease liabilities	$ 48,519	$ 51,886

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Finance lease cost:
Amortization of right-of-use assets	$ 2,594	$ 2,569
Interest on lease liabilities	515	640
Operating lease cost	309	126
Sublease income	(292)	(588)
Total lease cost	$ 3,126	$ 2,747

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 149	$ 99
Operating cash flows from finance leases	517	435
Financing cash flows from finance leases	2,814	3,017
Right-of-use assets obtained in exchange for new lease liabilities:
Finance leases	9	49,598
Operating leases	$ 0	$ 730

Leases - Schedule of Lease Term

Leases - Schedule of Lease Term and Discount Rate (Detail)	Mar. 31, 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 10 months 24 days	2 years 1 month 6 days
Weighted-average discount rate:
Finance leases	4.42%	4.42%
Operating leases	4.75%	4.75%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2020USD ($)
Finance Leases
2020 (Remaining nine month period)	$ 10,535
2021	13,680
2022	13,883
2023	12,523
Total future lease payments	50,621
Less: Interest	(3,680)
Present value of lease liabilities	46,941
Operating Leases
2020 (Remaining nine month period)	689
2021	657
2022	302
2023	0
Total future lease payments	1,648
Less: Interest	(70)
Present value of lease liabilities	$ 1,578

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Cash	$ 49,412	$ 40,715
Money market funds	72,148	85,551
Total cash and cash equivalents	$ 121,560	$ 126,266

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2020USD ($)Milestone	Dec. 31, 2019USD ($)
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 121,560,000	$ 126,266,000
Contractual maturities of available-for-sale investments	1 year
Other-than-temporary impairment loss	$ 0
Number of regulatory milestones | Milestone	2
Unbilled contract assets	$ 130,000,000	180,000,000
Active pharmaceutical ingredient product price change in estimated variable consideration	0	36,324,000
Accrued long-term co-promotional expenses	78,301,000	53,071,000
Accounts Receivable [Member]
Schedule of Available-for-sale Securities [Line Items]
Billed contract assets	50,000,000
Europe [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets	130,000,000
Astellas Agreement [Member] | Europe [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets	130,000,000
AstraZeneca Agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Unbilled contract assets	50,000,000
Accrued long-term co-promotional expenses	78,300,000	53,100,000
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	$ 29,800,000	$ 11,900,000

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 411,363	$ 467,850
Gross Unrealized Holding Gains	2,729	784
Gross Unrealized Holding Losses	0	(25)
Fair Value	414,092	468,609
U.S. treasury notes and bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	381,238	426,995
Gross Unrealized Holding Gains	2,516	536
Gross Unrealized Holding Losses	0	(25)
Fair Value	383,754	427,506
Certificate of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,000	30,000
Gross Unrealized Holding Gains	115	32
Gross Unrealized Holding Losses	0	0
Fair Value	30,115	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	98	130
Gross Unrealized Holding Losses	0	0
Fair Value	$ 223	$ 255

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule Of Investments [Abstract]
Raw materials	$ 459	$ 325
Work-in-progress	2,948	2,264
Finished goods	5,001	4,298
Total inventories	$ 8,408	$ 6,887

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Unbilled contract assets	$ 130,000	$ 180,000
Deferred revenues from associated contracts	(3,442)	(54,790)
Net unbilled contract assets	126,558	125,210
Prepaid assets	5,267	6,464
Other current assets	2,203	1,717
Total prepaid expenses and other current assets	$ 134,028	$ 133,391

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 143,283	$ 143,107
Less: accumulated depreciation	(103,225)	(100,364)
Property and equipment, net	40,058	42,743
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	101,721	101,548
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	17,359	17,329
Machinery [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,229	8,217
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,879	8,399
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	5,883	5,822
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,212	$ 1,792

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 16,704	$ 16,279
API product price adjustment	0	36,324
Payroll and related accruals	11,899	19,784
Property taxes and other	4,033	2,044
Professional services	4,608	4,842
Other	5,065	4,543
Total accrued liabilities	$ 42,309	$ 83,816

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Liabilities Noncurrent [Abstract]
Accrued long-term co-promotional expenses	$ 78,301	$ 53,071
Other long-term tax liabilities	8,786	8,913
Operating lease liabilities, non-current	678	942
Other	1,357	1,340
Total other long-term liabilities	$ 89,122	$ 64,266

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Allocated Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 16,916	$ 16,430
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	10,637	9,578
Selling, general and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 6,279	$ 6,852

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
	Mar. 31, 2020	Mar. 31, 2019
Employee stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 8 months 12 days	5 years 3 months 18 days
Expected volatility	68.30%	67.90%
Risk-free interest rate	0.90%	2.60%
Expected dividend yield	0.00%	0.00%
Weighted average estimated fair value	$ 17.24	$ 34.14
2014 Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	49.50%	48.10%
Expected volatility, maximum	57.70%	62.10%
Risk-free interest rate, minimum	1.50%	1.30%
Risk-free interest rate, maximum	2.90%	2.90%
Expected dividend yield	0.00%	0.00%
Weighted average estimated fair value	$ 18.57	$ 20.57
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
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

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Accounts receivable from related party	$ 3,723		$ 4,845
Accrued liabilities to related party	92		36,883
Unbilled contract asset	130,000		180,000
Net unbilled contract asset	126,558		125,210
Deferred revenue	3,442		54,790
Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset	130,000
Astellas Agreement [Member] | Japan [Member]
Related Party Transaction [Line Items]
Deferred revenue	269
Astellas Agreement [Member] | Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset	130,000
Deferred revenue	3,442
Astellas [Member] | Europe [Member]
Related Party Transaction [Line Items]
Unbilled contract asset	130,000
Net unbilled contract asset	126,600		125,200
Deferred revenue	3,400		4,800
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	4,700	$ 4,900
Expense related to collaboration agreements	100	$ 500
Accounts receivable from related party	3,700		4,800
Accrued liabilities to related party	100		$ 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	3 Months Ended
	Mar. 31, 2020USD ($)
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	$ 23.5
Manufacture and Supply of Roxadustat [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	11.9
Research and Pre-Clinical Stage Development Programs [Member]
Commitments And Contingencies [Line Items]
Future milestone payments	11
Other Purchases [Member]
Commitments And Contingencies [Line Items]
Outstanding non-cancelable contract obligations	$ 0.6