FibroGen (FGEN) 10-Q 8 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	FGEN
Entity Registrant Name	FIBROGEN INC
Entity Central Index Key	921,299
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		82,008,777

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 651,373	$ 173,782
Short-term investments	78,599	79,397
Accounts receivable ($4,580 and $4,102 from a related party)	8,628	10,448
Prepaid expenses and other current assets	2,856	2,889
Total current assets	741,456	266,516
Restricted time deposits	6,217	6,217
Long-term investments	16,767	71,010
Property and equipment, net	126,643	123,657
Other assets	3,809	2,152
Total assets	894,892	469,552
Current liabilities:
Accounts payable	6,407	6,223
Accrued liabilities ($479 and $1,615 to related parties)	54,117	50,914
Deferred revenue	7,974	7,988
Total current liabilities	68,498	65,125
Long-term portion of lease financing obligations	97,370	97,352
Product development obligations	16,922	14,854
Deferred rent	3,799	4,212
Deferred revenue, net of current	110,844	106,709
Other long-term liabilities	6,690	6,191
Total liabilities	304,123	294,443
Commitments and Contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized at September 30, 2017 and December 31, 2016; no shares issued and outstanding at September 30, 2017 and December 31, 2016	0	0
Common stock, $0.01 par value; 225,000 shares authorized at September 30, 2017 and December 31, 2016; 81,814 and 63,665 shares issued and outstanding at September 30, 2017 and December 31, 2016	818	637
Additional paid-in capital	1,146,112	625,903
Accumulated other comprehensive loss	(1,609)	(960)
Accumulated deficit	(573,823)	(469,742)
Total stockholders’ equity	571,498	155,838
Non-controlling interests	19,271	19,271
Total equity	590,769	175,109
Total liabilities, stockholders’ equity and non-controlling interests	$ 894,892	$ 469,552

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Accounts receivable from related party	$ 4,580	$ 4,102
Accrued liabilities to related parties	$ 479	$ 1,615
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	81,814,000	63,665,000
Common stock, shares outstanding	81,814,000	63,665,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
License and milestone revenue (includes $4,125, $4,371, $11,652 and $20,727 from a related party)	$ 19,997	$ 20,867	$ 60,930	$ 113,802
Collaboration services and other revenue (includes $445, $436, $1,230 and $1,114 from a related party)	7,275	9,235	22,230	33,863
Total revenue	27,272	30,102	83,160	147,665
Operating expenses:
Research and development	50,336	40,558	144,049	136,599
General and administrative	12,953	11,646	37,908	33,440
Total operating expenses	63,289	52,204	181,957	170,039
Loss from operations	(36,017)	(22,102)	(98,797)	(22,374)
Interest and other, net
Interest expense	(2,769)	(2,760)	(7,901)	(7,975)
Interest income and other, net	1,106	866	2,783	2,411
Total interest and other, net	(1,663)	(1,894)	(5,118)	(5,564)
Loss before income taxes	(37,680)	(23,996)	(103,915)	(27,938)
Provision for (benefit from) income taxes	57	158	166	(260)
Net loss	$ (37,737)	$ (24,154)	$ (104,081)	$ (27,678)
Net loss per share - basic and diluted	$ (0.50)	$ (0.38)	$ (1.49)	$ (0.44)
Weighted average number of common shares used to calculate net loss per share - basic and diluted	75,891	62,858	69,899	62,543

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
License and milestone revenue from a related party	$ 19,997	$ 20,867	$ 60,930	$ 113,802
Collaboration services and other revenue from a related party	7,275	9,235	22,230	33,863
Astellas Agreement [Member]
License and milestone revenue from a related party	4,125	4,371	11,652	20,727
Collaboration services and other revenue from a related party	$ 445	$ 436	$ 1,230	$ 1,114

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (37,737)	$ (24,154)	$ (104,081)	$ (27,678)
Other comprehensive income (loss):
Foreign currency translation adjustments	(578)	(184)	(1,827)	(446)
Available-for-sale investments:
Unrealized gain on investments, net of tax effect	403	(144)	1,250	745
Reclassification from accumulated other comprehensive loss	(47)	19	(72)	19
Net change in unrealized gain on available-for-sale investments	356	(125)	1,178	764
Other comprehensive income (loss), net of taxes	(222)	(309)	(649)	318
Comprehensive loss	$ (37,959)	$ (24,463)	$ (104,730)	$ (27,360)

Condensed Consolidated Stateme7

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net loss	$ (104,081)	$ (27,678)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	4,582	4,520
Amortization of premium on investments	1,503	2,080
Unrealized loss (gain) on short-term investments	3	(436)
Gain on disposal of property and equipment	3	0
Stock-based compensation	27,608	24,256
Tax benefit on unrealized gain on available-for-sale securities	0	(371)
Realized gain on sales of available-for-sale securities	(143)	(37)
Changes in operating assets and liabilities:
Accounts receivable	1,820	7,713
Prepaid expenses and other current assets	33	23
Other assets	(1,657)	23
Accounts payable	184	(4,482)
Accrued liabilities	(114)	4,231
Deferred revenue	4,121	14,733
Lease financing liability	474	690
Other long-term liabilities	337	388
Net cash provided by (used in) operating activities	(65,327)	25,653
Investing activities
Purchases of property and equipment	(4,992)	(1,106)
Proceeds from sale of property and equipment	5	0
Purchases of available-for-sale securities	(102)	(72)
Proceeds from sales of available-for-sale securities	21,109	4,298
Proceeds from maturities of available-for-sale securities	33,849	12,617
Net cash provided by investing activities	49,869	15,737
Financing activities
Repayments of lease liability	(302)	(302)
Proceeds from follow-on offering, net of underwriting discounts and commission costs	471,205	0
Cash paid for payroll taxes on restricted stock unit releases	(5,970)	(2,242)
Proceeds from issuance of common stock	28,556	6,137
Payments of deferred offering costs	(430)	0
Net cash provided by financing activities	493,059	3,593
Effect of exchange rate change on cash and cash equivalents	(10)	(24)
Net increase in cash and cash equivalents	477,591	44,959
Total cash and cash equivalents at beginning of period	173,782	153,324
Total cash and cash equivalents at end of period	$ 651,373	$ 198,283

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
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 is a research-based biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics agents to treat serious unmet medical needs. The Company’s focus in the areas of fibrosis and hypoxia-inducible factor (“HIF”) biology has generated multiple programs targeting various therapeutic areas. The Company’s most advanced product candidate, roxadustat, or FG-4592, is an oral small molecule inhibitor of HIF prolyl hydroxylases (“HIF-PHs”) in Phase 3 clinical development for the treatment of anemia in chronic kidney disease (“CKD”). Pamrevlumab, or FG-3019, is the Company’s monoclonal antibody in Phase 2 clinical development for the treatment of idiopathic pulmonary fibrosis (“IPF”), pancreatic cancer, Duchenne muscular dystrophy (“DMD”) and liver fibrosis. The Company has taken a global approach with respect to the development and future commercialization of its product candidates, and this includes development and commercialization in the People’s Republic of China (“China”). The Company is capitalizing on its extensive experience in fibrosis and hypoxia inducible factor (“HIF”) biology and clinical development to advance a pipeline of innovative medicines for the treatment of anemia, fibrotic disease cancer, corneal blindness and other serious unmet medical needs. On April 11, 2017, the Company closed the follow-on offering of its common stock. In this offering, the Company sold 5,228,750 shares of its common stock at a public offering price of $22.95 per share. Net proceeds from this offering were $115.1 million, after deducting underwriting discounts and commissions of $4.9 million. In addition, the offering expenses were approximately $0.6 million in total. On August 24, 2017, the Company completed another follow-on offering of its common stock. In this offering, the Company sold a total of 9,200,000 shares of its common stock at a public offering price of $40.75 per share. Net proceeds from this offering were $356.2 million, after deducting underwriting discounts and commissions of $18.7 million. In addition, the offering expenses were approximately $0.4 million in total. 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 in 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 United States of America (“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 United States (“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 December 31, 2016 condensed consolidated balance sheet data contained within this Form 10-Q was derived from audited consolidated financial statements included in the Company’s Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2016 (“2016 Form 10-K”), but does not include all disclosures required by U.S. GAAP. The financial information included herein should be read in conjunction with the consolidated financial statements and related notes in the 2016 Form 10-K. 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 2016 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, estimates of accruals related to clinical trial costs, valuation allowances for deferred tax assets, and valuation and recognition of stock-based compensation. 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 our opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of our financial position, results of operations and cash flows for the interim periods presented. Recently Issued and Adopted Accounting Guidance In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) Compensation - Stock Compensation (Topic 718) . Recently Issued Accounting Guidance Not Yet Adopted In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In January 2016, the FASB issued ASU 2016-01, Financial Instruments-Overall (Subtopic 825-10) In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) Revenue Recognition Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers

Collaboration Agreements

Collaboration Agreements	9 Months Ended
	Sep. 30, 2017
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 Pharma Inc. (“Astellas”) for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). The Japan Agreement also provides for additional development and regulatory approval milestone payments up to $117.5 million, a commercial sales related milestone of $15.0 million and additional consideration based on net sales (as defined) in the low 20% range after commercial launch. A clinical milestone payment of $12.5 million was received in 2013. During the second quarter of 2016, the Company recognized $10.0 million of revenue as a result of the initiation by Astellas of the first Phase 3 clinical study in Japan of roxadustat for treatment of anemia associated with chronic kidney disease in patients on dialysis. The amount was received in early July 2016. The Company evaluated the criteria under ASC 605-28 and concluded that the aforementioned milestone was substantive. 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. Clinical milestone payments of $40.0 million and $50.0 million were received in 2010 and 2012, respectively. The Company evaluated the criteria under ASC 605-28 and concluded that each of those milestones was substantive. 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. 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 has agreed to pay upfront, non-contingent and time-based payments totaling $374.0 million, which were fully received in various amounts through June 2016. In addition, the U.S./RoW Agreement also provides for development and regulatory approval based milestone payments of up to $550.0 million, which include potential future indications which the companies choose to pursue, and commercial related milestone payments of up to $325.0 million. During 2015, the Company received a $15.0 million development milestone payment as a result of the finalization of its two audited pre-clinical carcinogenicity study reports. The Company evaluated the criteria under ASC 605-28 and concluded that the aforementioned milestone was substantive. Under the U.S./RoW Agreement, the Company and AstraZeneca will share equally in the development costs of roxadustat not already paid for by Astellas, up to a total of $233.0 million (i.e. the Company’s share of development costs is $116.5 million, which was reached during the fourth quarter of 2015). Any additional development costs incurred by FibroGen during the development period in excess of the $233.0 million (aggregated spend) will be fully reimbursed by AstraZeneca. AstraZeneca will pay the Company tiered royalty payments on AstraZeneca’s future net sales (as defined in the agreement) of roxadustat in the low 20% range. In addition, the Company will receive a transfer price for delivery of commercial product based on a percentage of AstraZeneca’s net sales (as defined in the agreement) in the low- to mid-single digit range. 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, which were fully received in 2014. In addition, the China Agreement provides for AstraZeneca to pay regulatory approval and other approval related milestones of up to $161.0 million. The China Agreement also provides for sales related milestone payments of up to $167.5 million and contingent payments of $20.0 million related to possible future compounds. 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. In September 2016, AstraZeneca approved the protocol related to the development of roxadustat for the treatment of anemia in patients with myelodysplastic syndromes (“MDS”), for which the Company has received approval from the China Food and Drug Administration for its clinical trial application for a Phase 2/3 trial and acceptance of its investigational new drug application from the U.S. Food and Drug Administration for a Phase 3 trial. As a result, for revenue recognition purposes, during the third quarter of 2016, the Company extended the estimated joint development service period for the AstraZeneca agreements from the end of 2018 to the end of 2020, to allow for development of MDS. In October 2017, the China Food and Drug Administration accepted the Company’s recently submitted New Drug Application (“NDA”) for registration of roxadustat for anemia in dialysis-dependent CKD and non-dialysis-dependent CKD (NDD-CKD) patients. This NDA submission triggers a $15.0 million milestone payment to the Company by AstraZeneca, which is expected to be received and fully recognized under the Company’s current revenue recognition policy as license and milestone revenue in the fourth quarter of 2017. Summary of Revenue Recognized Under the Collaboration Agreements The table below summarizes the accounting treatment for the various deliverables pursuant to each of the Astellas and AstraZeneca agreements. License amounts identified below are included in the “License and milestone revenue” line item in the condensed consolidated statements of operations. All other elements identified below are included in the “Collaboration services and other revenue” line item in the condensed consolidated statements of operations. Amounts recognized as revenue under the Japan Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Deliverable 2017 2016 2017 2016 Japan License $ 445 $ 3,041 $ 936 $ 3,159 Milestones — — — 10,000 Total license and milestone revenue 445 $ 3,041 $ 936 $ 13,159 Collaboration services revenue* 22 $ 144 $ 46 $ 151 * When and if available compounds, manufacturing — clinical supplies and committee services have each been identified as separate units of accounting with standalone value and amounts allocable to these elements have been recognized and classified within the Collaboration services revenue line item within the condensed consolidated statements of operations. The total arrangement consideration has been allocated to each of the following deliverables under the Japan Agreement, along with any associated deferred revenue as follows (in thousands): Cumulative Revenue Through September 30, 2017 Deferred Revenue at September 30, 2017 Total Consideration Through September 30, 2017 License $ 46,646 $ — $ 46,646 When and if available compounds 24 24 48 Manufacturing--clinical supplies 2,164 — 2,164 Committee services 21 — 21 Total license and collaboration services revenue $ 48,855 $ 24 $ 48,879 Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Deliverable 2017 2016 2017 2016 Europe License $ 3,680 $ 1,330 $ 10,716 $ 7,568 Milestones — — — — Total license and milestone revenue 3,680 1,330 10,716 7,568 Collaboration services revenue* $ 423 $ 292 $ 1,184 $ 963 * When and if available compounds, manufacturing — clinical supplies, development services — in progress at the time of signing of the agreement, and committee services have each been identified as a separate unit of accounting with standalone value and amounts allocable to these units have been recognized in revenue as services are performed and classified within the Collaboration services revenue line item within the condensed consolidated statements of operations. The total arrangement consideration has been allocated to each of the following deliverables under the Europe Agreement, along with any associated deferred revenue as follows (in thousands): Cumulative Revenue Through September 30, 2017 Deferred Revenue at September 30, 2017 Total Consideration Through September 30, 2017 License $ 422,988 $ — $ 422,988 When and if available compounds 434 394 828 Manufacturing--clinical supplies 10,132 — 10,132 Development services--in progress 33,892 — 33,892 Committee services 293 — 293 Total license and collaboration services revenue $ 467,739 $ 394 $ 468,133 Amounts recognized as revenue under the U.S./RoW Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Deliverable 2017 2016 2017 2016 U.S. / RoW and China License $ 15,872 $ 16,496 $ 49,278 $ 93,075 Milestones — — — — Total license and milestone revenue 15,872 16,496 49,278 93,075 Collaboration services revenue* 6,830 8,784 20,997 32,723 China single unit of accounting** $ — $ — $ — $ — * Co-development, information sharing, and committee services have been combined into a single unit of accounting because the requirements to share information and serve on committees are useful only in combination with the development services, and because all three items are delivered over the same period while manufacturing — clinical supplies has been identified as a separate unit of accounting with standalone value and amounts allocable to this unit of accounting have been recognized and classified within the Collaboration services revenue line item within the condensed consolidated statements of operations. ** All revenues attributable to the China unit of accounting are deferred until all deliverables are met. The China license and collaboration services elements have been combined into a single unit of accounting and consideration allocable to this unit is being deferred due to FibroGen’s retention of manufacturing rights and lack of standalone value. The total arrangement consideration has been allocated to each of the following deliverables under the U.S./RoW Agreement, along with any associated deferred revenue as follows (in thousands): Cumulative Revenue Through September 30, 2017 Deferred Revenue at September 30, 2017 Total Consideration Through September 30, 2017 License $ 451,974 $ — $ 451,974 Co-development, information sharing & committee services 111,693 25,723 137,416 Manufacturing--clinical supplies 436 34 470 China-single unit of accounting — 92,643 92,643 Total license and collaboration services revenue $ 564,103 $ 118,400 $ 682,503 Other Revenues Other revenues consist of royalty payments received, which are recorded on a monthly basis as they are reported to the Company, and collagen feasibility sales. Other revenues were immaterial for all periods presented. Deferred Revenue Deferred revenue represents amounts 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 deliverables. 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 deliverables. The long term portion of deferred revenue also 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, which is not expected to occur within the next year.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The fair values of our financial assets that are measured on a recurring basis are as follows (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 75,872 $ — $ 75,872 Bond and mutual funds 18,251 — — 18,251 Equity investments 207 — — 207 Money market funds 546,498 — — 546,498 Certificate of deposits — 1,036 — 1,036 Total $ 564,956 $ 76,908 $ — $ 641,864 December 31, 2016 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 126,683 $ — $ 126,683 Bond and mutual funds 22,462 — — 22,462 Equity investments 225 — — 225 Money market funds 94,543 — — 94,543 Certificate of deposits — 1,037 — 1,037 Total $ 117,230 $ 127,720 $ — $ 244,950 Our 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 our financial liabilities that are carried at historical cost are as follows (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 98,028 $ 98,028 December 31, 2016 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 97,856 $ 97,856 The fair values of our 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.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	4. Balance Sheet Components Cash and Cash Equivalents Cash and cash equivalents consisted of the following (in thousands): September 30, 2017 December 31, 2016 Cash $ 104,875 $ 79,239 Money market funds 546,498 94,543 Total cash and cash equivalents $ 651,373 $ 173,782 At September 30, 2017 and December 31, 2016, a total of $19.1 million and $24.3 million, respectively, of our cash and cash equivalents were held outside of the U.S. in our foreign subsidiaries to be used primarily for our China operations. Investments All investments are classified as available-for-sale. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s available-for-sale investments by major investments type are summarized in the tables below (in thousands): September 30, 2017 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 75,826 $ 62 $ (16 ) $ 75,872 Certificate of deposits 1,036 — — 1,036 Bond and mutual funds 17,182 1,069 — 18,251 Equity investments 126 81 — 207 Total investments $ 94,170 $ 1,212 $ (16 ) $ 95,366 December 31, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 126,550 $ 182 $ (49 ) $ 126,683 Certificate of deposits 1,037 — — 1,037 Bond and mutual funds 22,305 157 — 22,462 Equity investments 125 100 — 225 Total investments $ 150,017 $ 439 $ (49 ) $ 150,407 At September 30, 2017, all of the available-for-sale investments had contractual maturities within two years. The Company periodically reviews its available-for-sale investments for other-than-temporary impairment. The Company considers factors such as the duration, severity and the reason for the decline in value, the potential recovery period and our intent to sell. For debt securities, the Company also considers whether (i) it is more likely than not that the Company will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. During the three and nine months ended September 30, 2017 and 2016, the Company did not recognize any other-than-temporary impairment loss. Accrued Liabilities Accrued liabilities consisted of the following (in thousands): September 30, 2017 December 31, 2016 Preclinical and clinical trial accruals $ 26,989 $ 29,550 Payroll and related accruals 14,654 14,232 Professional services 2,144 1,252 Other 10,330 5,880 Total accrued liabilities $ 54,117 $ 50,914

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	5. Stock-Based Compensation Stock-based compensation expense was allocated to research and development and general and administrative expense as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Research and development $ 5,538 $ 5,074 $ 16,060 $ 14,629 General and administrative 4,090 3,438 11,548 9,627 Total stock-based compensation expense $ 9,628 $ 8,512 $ 27,608 $ 24,256 The assumptions used to estimate the fair value of stock options granted and purchases under the Company’s 2014 Employee Share Purchase Plan (“ESPP”) using the Black-Scholes option valuation model were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Stock Options Expected term (in years) 5.3 5.3 5.7 5.3 Expected volatility 69.5 % 72.5 % 71.5 % 69.8 % Risk-free interest rate 1.9 1.2 2.2 1.4 Expected dividend yield — — — — Weighted average estimated fair value $ 26.47 $ 10.73 $ 16.63 $ 11.46 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Expected volatility 52.8 - 76.0 % 63.7 - 80.7 % 52.8 - 77.2 % 61.9 - 80.7 % Risk-free interest rate 0.6 - 1.3 % 0.4 - 0.9 % 0.5 - 1.3 % 0.2 - 0.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 9.67 $ 9.04 $ 9.15 $ 10.27

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes The provisions for income taxes for the three and nine months ended September 30, 2017 were due to foreign taxes. The provision for income taxes for the three months ended September 30, 2016 was due to the discrete tax effect arising from an unrealized loss in other comprehensive income (loss) related to available-for-sale securities, and foreign taxes. The benefit from income taxes for the nine months ended September 30, 2016 was due to the discrete tax effect arising from cumulative unrealized gains in other comprehensive income (loss) related to available-for-sale securities, partially offset by foreign taxes. Based upon the weight of available evidence, which includes its historical operating performance, reported cumulative net losses since inception and expected continuing net loss, the Company has established and continues to maintain a full valuation allowance against its deferred tax assets as it does not currently believe that realization of those assets is more likely than not.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	7. 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 $4.6 million and $4.8 million during the three months ended September 30, 2017 and 2016, respectively, and $12.9 million and $21.8 million during the nine months ended September 30, 2017 and 2016, respectively. The Company recorded expense related to collaboration agreements with Astellas of $0.2 million and $1.8 million during the three months ended September 30, 2017 and 2016, respectively, and $0.8 million and $4.8 million during the nine months ended September 30, 2017 and 2016, respectively. As of September 30, 2017 and December 31, 2016, accounts receivable from Astellas were $4.6 million and $4.1 million, respectively, and amounts due to Astellas were $0.5 million and $1.6 million, respectively. Julian N. Stern, a director of the Company from November 1996 through June 2017, is currently serving as corporate secretary of the Company and is of counsel to the law firm of Goodwin Procter LLP, which he joined in 2008. He has received, and continues to receive, no compensation from Goodwin Procter LLP since joining as counsel. The Company retains Goodwin Procter LLP as legal counsel for various matters, primarily consisting of intellectual property matters. There was no payment to Goodwin Procter LLP during the three and nine months ended September 30, 2017. The Company’s payments to Goodwin Procter LLP during the three and nine months ended September 30, 2016 were immaterial. As of September 30, 2017 and December 31, 2016, the balance of the accrued liability for Goodwin Proctor LLP was zero.

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Event	8. Subsequent Event In October 2017, the China Food and Drug Administration accepted the Company’s recently submitted NDA for registration of roxadustat for anemia in dialysis-dependent CKD and NDD-CKD patients. This NDA submission triggers a $15.0 million milestone payment to the Company by AstraZeneca, which is expected to be received and fully recognized under the Company’s current revenue recognition policy as license and milestone revenue in the fourth quarter of 2017.

Significant Accounting Polici16

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Description of Operations	Description of Operations FibroGen, Inc. (“FibroGen” or the “Company”) was incorporated in 1993 in Delaware and is a research-based biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics agents to treat serious unmet medical needs. The Company’s focus in the areas of fibrosis and hypoxia-inducible factor (“HIF”) biology has generated multiple programs targeting various therapeutic areas. The Company’s most advanced product candidate, roxadustat, or FG-4592, is an oral small molecule inhibitor of HIF prolyl hydroxylases (“HIF-PHs”) in Phase 3 clinical development for the treatment of anemia in chronic kidney disease (“CKD”). Pamrevlumab, or FG-3019, is the Company’s monoclonal antibody in Phase 2 clinical development for the treatment of idiopathic pulmonary fibrosis (“IPF”), pancreatic cancer, Duchenne muscular dystrophy (“DMD”) and liver fibrosis. The Company has taken a global approach with respect to the development and future commercialization of its product candidates, and this includes development and commercialization in the People’s Republic of China (“China”). The Company is capitalizing on its extensive experience in fibrosis and hypoxia inducible factor (“HIF”) biology and clinical development to advance a pipeline of innovative medicines for the treatment of anemia, fibrotic disease cancer, corneal blindness and other serious unmet medical needs. On April 11, 2017, the Company closed the follow-on offering of its common stock. In this offering, the Company sold 5,228,750 shares of its common stock at a public offering price of $22.95 per share. Net proceeds from this offering were $115.1 million, after deducting underwriting discounts and commissions of $4.9 million. In addition, the offering expenses were approximately $0.6 million in total. On August 24, 2017, the Company completed another follow-on offering of its common stock. In this offering, the Company sold a total of 9,200,000 shares of its common stock at a public offering price of $40.75 per share. Net proceeds from this offering were $356.2 million, after deducting underwriting discounts and commissions of $18.7 million. In addition, the offering expenses were approximately $0.4 million in total.
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 in 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 United States of America (“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 United States (“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 December 31, 2016 condensed consolidated balance sheet data contained within this Form 10-Q was derived from audited consolidated financial statements included in the Company’s Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2016 (“2016 Form 10-K”), but does not include all disclosures required by U.S. GAAP. The financial information included herein should be read in conjunction with the consolidated financial statements and related notes in the 2016 Form 10-K. 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 2016 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, estimates of accruals related to clinical trial costs, valuation allowances for deferred tax assets, and valuation and recognition of stock-based compensation. 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 our opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of our financial position, results of operations and cash flows for the interim periods presented.
Recently Issued and Adopted Accounting Guidance	Recently Issued and Adopted Accounting Guidance In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) Compensation - Stock Compensation (Topic 718) .
Recently Issued Accounting Guidance Not Yet Adopted	Recently Issued Accounting Guidance Not Yet Adopted In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In January 2016, the FASB issued ASU 2016-01, Financial Instruments-Overall (Subtopic 825-10) In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) Revenue Recognition Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers

Collaboration Agreements (Table

Collaboration Agreements (Tables)	9 Months Ended
	Sep. 30, 2017
Japan [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Japan Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Deliverable 2017 2016 2017 2016 Japan License $ 445 $ 3,041 $ 936 $ 3,159 Milestones — — — 10,000 Total license and milestone revenue 445 $ 3,041 $ 936 $ 13,159 Collaboration services revenue* 22 $ 144 $ 46 $ 151 * When and if available compounds, manufacturing — clinical supplies and committee services have each been identified as separate units of accounting with standalone value and amounts allocable to these elements have been recognized and classified within the Collaboration services revenue line item within the condensed consolidated statements of operations.
Total Arrangement Consideration Allocated to Deliverables along with Associated Deferred Revenue	The total arrangement consideration has been allocated to each of the following deliverables under the Japan Agreement, along with any associated deferred revenue as follows (in thousands): Cumulative Revenue Through September 30, 2017 Deferred Revenue at September 30, 2017 Total Consideration Through September 30, 2017 License $ 46,646 $ — $ 46,646 When and if available compounds 24 24 48 Manufacturing--clinical supplies 2,164 — 2,164 Committee services 21 — 21 Total license and collaboration services revenue $ 48,855 $ 24 $ 48,879
Europe [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Agreement Deliverable 2017 2016 2017 2016 Europe License $ 3,680 $ 1,330 $ 10,716 $ 7,568 Milestones — — — — Total license and milestone revenue 3,680 1,330 10,716 7,568 Collaboration services revenue* $ 423 $ 292 $ 1,184 $ 963 * When and if available compounds, manufacturing — clinical supplies, development services — in progress at the time of signing of the agreement, and committee services have each been identified as a separate unit of accounting with standalone value and amounts allocable to these units have been recognized in revenue as services are performed and classified within the Collaboration services revenue line item within the condensed consolidated statements of operations.
Total Arrangement Consideration Allocated to Deliverables along with Associated Deferred Revenue	The total arrangement consideration has been allocated to each of the following deliverables under the Europe Agreement, along with any associated deferred revenue as follows (in thousands): Cumulative Revenue Through September 30, 2017 Deferred Revenue at September 30, 2017 Total Consideration Through September 30, 2017 License $ 422,988 $ — $ 422,988 When and if available compounds 434 394 828 Manufacturing--clinical supplies 10,132 — 10,132 Development services--in progress 33,892 — 33,892 Committee services 293 — 293 Total license and collaboration services revenue $ 467,739 $ 394 $ 468,133
U.S./RoW [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 September 30, Nine Months Ended September 30, Agreement Deliverable 2017 2016 2017 2016 U.S. / RoW and China License $ 15,872 $ 16,496 $ 49,278 $ 93,075 Milestones — — — — Total license and milestone revenue 15,872 16,496 49,278 93,075 Collaboration services revenue* 6,830 8,784 20,997 32,723 China single unit of accounting** $ — $ — $ — $ — * Co-development, information sharing, and committee services have been combined into a single unit of accounting because the requirements to share information and serve on committees are useful only in combination with the development services, and because all three items are delivered over the same period while manufacturing — clinical supplies has been identified as a separate unit of accounting with standalone value and amounts allocable to this unit of accounting have been recognized and classified within the Collaboration services revenue line item within the condensed consolidated statements of operations. ** All revenues attributable to the China unit of accounting are deferred until all deliverables are met. The China license and collaboration services elements have been combined into a single unit of accounting and consideration allocable to this unit is being deferred due to FibroGen’s retention of manufacturing rights and lack of standalone value.
Total Arrangement Consideration Allocated to Deliverables along with Associated Deferred Revenue	The total arrangement consideration has been allocated to each of the following deliverables under the U.S./RoW Agreement, along with any associated deferred revenue as follows (in thousands): Cumulative Revenue Through September 30, 2017 Deferred Revenue at September 30, 2017 Total Consideration Through September 30, 2017 License $ 451,974 $ — $ 451,974 Co-development, information sharing & committee services 111,693 25,723 137,416 Manufacturing--clinical supplies 436 34 470 China-single unit of accounting — 92,643 92,643 Total license and collaboration services revenue $ 564,103 $ 118,400 $ 682,503

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Values of Financial Assets Measured on Recurring Basis	The fair values of our financial assets that are measured on a recurring basis are as follows (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 75,872 $ — $ 75,872 Bond and mutual funds 18,251 — — 18,251 Equity investments 207 — — 207 Money market funds 546,498 — — 546,498 Certificate of deposits — 1,036 — 1,036 Total $ 564,956 $ 76,908 $ — $ 641,864 December 31, 2016 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 126,683 $ — $ 126,683 Bond and mutual funds 22,462 — — 22,462 Equity investments 225 — — 225 Money market funds 94,543 — — 94,543 Certificate of deposits — 1,037 — 1,037 Total $ 117,230 $ 127,720 $ — $ 244,950
Fair Values of Financial Liabilities Carried at Historical Cost	The fair values of our financial liabilities that are carried at historical cost are as follows (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 98,028 $ 98,028 December 31, 2016 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 97,856 $ 97,856

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): September 30, 2017 December 31, 2016 Cash $ 104,875 $ 79,239 Money market funds 546,498 94,543 Total cash and cash equivalents $ 651,373 $ 173,782
Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments	All investments are classified as available-for-sale. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s available-for-sale investments by major investments type are summarized in the tables below (in thousands): September 30, 2017 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 75,826 $ 62 $ (16 ) $ 75,872 Certificate of deposits 1,036 — — 1,036 Bond and mutual funds 17,182 1,069 — 18,251 Equity investments 126 81 — 207 Total investments $ 94,170 $ 1,212 $ (16 ) $ 95,366 December 31, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 126,550 $ 182 $ (49 ) $ 126,683 Certificate of deposits 1,037 — — 1,037 Bond and mutual funds 22,305 157 — 22,462 Equity investments 125 100 — 225 Total investments $ 150,017 $ 439 $ (49 ) $ 150,407
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): September 30, 2017 December 31, 2016 Preclinical and clinical trial accruals $ 26,989 $ 29,550 Payroll and related accruals 14,654 14,232 Professional services 2,144 1,252 Other 10,330 5,880 Total accrued liabilities $ 54,117 $ 50,914

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
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 general and administrative expense as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Research and development $ 5,538 $ 5,074 $ 16,060 $ 14,629 General and administrative 4,090 3,438 11,548 9,627 Total stock-based compensation expense $ 9,628 $ 8,512 $ 27,608 $ 24,256
Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Purchases under 2014 Employee Share Purchase Plan	The assumptions used to estimate the fair value of stock options granted and purchases under the Company’s 2014 Employee Share Purchase Plan (“ESPP”) using the Black-Scholes option valuation model were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Stock Options Expected term (in years) 5.3 5.3 5.7 5.3 Expected volatility 69.5 % 72.5 % 71.5 % 69.8 % Risk-free interest rate 1.9 1.2 2.2 1.4 Expected dividend yield — — — — Weighted average estimated fair value $ 26.47 $ 10.73 $ 16.63 $ 11.46 ESPPs Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Expected volatility 52.8 - 76.0 % 63.7 - 80.7 % 52.8 - 77.2 % 61.9 - 80.7 % Risk-free interest rate 0.6 - 1.3 % 0.4 - 0.9 % 0.5 - 1.3 % 0.2 - 0.9 % Expected dividend yield — — — — Weighted average estimated fair value $ 9.67 $ 9.04 $ 9.15 $ 10.27

Significant Accounting Polici21

Significant Accounting Policies - Additional Information (Detail)	Aug. 24, 2017USD ($)$ / sharesshares	Apr. 11, 2017USD ($)$ / sharesshares	Sep. 30, 2017USD ($)Segment	Sep. 30, 2016USD ($)
Accounting Policy [Line Items]
Net proceeds from offering			$ 28,556,000	$ 6,137,000
Number of operating segment | Segment			1
ASU 2016-09 [Member]
Accounting Policy [Line Items]
Retrospective increase in deferred tax assets for previously unrecognized excess tax benefits			$ 19,500,000
Increase in valuation allowance			19,500,000
Net impact to accumulated deficit			$ 0
Follow-on Offering [Member]
Accounting Policy [Line Items]
Common stock shares sold | shares	9,200,000	5,228,750
Public offering price | $ / shares	$ 40.75	$ 22.95
Net proceeds from offering	$ 356,200,000	$ 115,100,000
Underwriting discounts and commissions	18,700,000	4,900,000
Offering expenses	$ 400,000	$ 600,000

Collaboration Agreements - Aste

Collaboration Agreements - Astellas Agreements - Additional Information (Detail) - Astellas Agreement [Member] - USD ($) $ in Thousands

1 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

35 Months Ended

45 Months Ended

Apr. 30, 2006

Jun. 30, 2005

Sep. 30, 2017

Sep. 30, 2016

Jun. 30, 2016

Sep. 30, 2017

Sep. 30, 2016

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2010

Feb. 28, 2009

Feb. 28, 2009

Japan [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront, non-contingent and time-based payments received

$ 40,100

Development and regulatory approval milestones

$ 117,500

Commercial sales milestone

$ 15,000

Additional consideration based on net sales description

Low 20% range

Clinical development milestones

$ 12,500

Milestones revenue

$ 0

$ 0

$ 10,000

$ 0

$ 10,000

Europe [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront, non-contingent and time-based payments received

$ 320,000

Development and regulatory approval milestones

$ 425,000

Additional consideration based on net sales description

Low 20% range

Clinical development milestones

$ 50,000

$ 40,000

Milestones revenue

$ 0

$ 0

$ 0

$ 0

Percentage of joint development costs committed to fund

50.00%

Collaboration Agreements - Astr

Collaboration Agreements - AstraZeneca Agreements - Additional Information 1 (Detail) - AstraZeneca Agreements [Member] - USD ($) $ in Thousands	Jul. 30, 2013	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2015
U.S./RoW [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected upfront, non-contingent and time-based payments	$ 374,000
Development and regulatory approval milestones	550,000
Commercial sales milestone	325,000
Shared development costs					$ 233,000
Additional consideration based on net sales description						Low 20% range
Milestone payment, revenue recognition			$ 0	$ 0		$ 0	$ 0
U.S./RoW [Member] | FibroGen, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Shared development costs					$ 116,500
U.S./RoW [Member] | Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receipt of development milestone payment								$ 15,000
China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development and regulatory approval milestones	161,000
Commercial sales milestone	167,500
Proceeds from upfront payments	28,200
Contingent payment	$ 20,000
Estimated joint development service period				2,018
Estimated joint development extended service period				2,020
China [Member] | Scenario, Forecast [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment, revenue recognition		$ 15,000

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total license and milestone revenue	$ 19,997	$ 20,867		$ 60,930	$ 113,802
Collaboration services and other revenue from a related party	7,275	9,235		22,230	33,863
Revenue recognized	27,272	30,102		83,160	147,665
Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total license and milestone revenue	4,125	4,371		11,652	20,727
Collaboration services and other revenue from a related party	445	436		1,230	1,114
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
License revenue	445	3,041		936	3,159
Milestones revenue	0	0	$ 10,000	0	10,000
Total license and milestone revenue	445	3,041		936	13,159
Collaboration services and other revenue from a related party	22	144		46	151
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
License revenue	3,680	1,330		10,716	7,568
Milestones revenue	0	0		0	0
Total license and milestone revenue	3,680	1,330		10,716	7,568
Collaboration services and other revenue from a related party	423	292		1,184	963
AstraZeneca Agreements [Member] | China-single unit of accounting [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue recognized	0	0		0	0
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
License revenue	15,872	16,496		49,278	93,075
Milestones revenue	0	0		0	0
Total license and milestone revenue	15,872	16,496		49,278	93,075
Collaboration services and other revenue from a related party	$ 6,830	$ 8,784		$ 20,997	$ 32,723

Collaboration Agreements - Tota

Collaboration Agreements - Total Arrangement Consideration Allocated to Deliverables along with Associated Deferred Revenue (Detail) $ in Thousands	Sep. 30, 2017USD ($)
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	$ 48,855
Deferred Revenue	24
Total Consideration	48,879
Astellas Agreement [Member] | Japan [Member] | License [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	46,646
Deferred Revenue	0
Total Consideration	46,646
Astellas Agreement [Member] | Japan [Member] | When and if available compounds [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	24
Deferred Revenue	24
Total Consideration	48
Astellas Agreement [Member] | Japan [Member] | Manufacturing-clinical supplies [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	2,164
Deferred Revenue	0
Total Consideration	2,164
Astellas Agreement [Member] | Japan [Member] | Committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	21
Deferred Revenue	0
Total Consideration	21
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	467,739
Deferred Revenue	394
Total Consideration	468,133
Astellas Agreement [Member] | Europe [Member] | License [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	422,988
Deferred Revenue	0
Total Consideration	422,988
Astellas Agreement [Member] | Europe [Member] | When and if available compounds [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	434
Deferred Revenue	394
Total Consideration	828
Astellas Agreement [Member] | Europe [Member] | Manufacturing-clinical supplies [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	10,132
Deferred Revenue	0
Total Consideration	10,132
Astellas Agreement [Member] | Europe [Member] | Committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	293
Deferred Revenue	0
Total Consideration	293
Astellas Agreement [Member] | Europe [Member] | Development services-in progress [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	33,892
Deferred Revenue	0
Total Consideration	33,892
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	564,103
Deferred Revenue	118,400
Total Consideration	682,503
AstraZeneca Agreements [Member] | U.S./RoW [Member] | License [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	451,974
Deferred Revenue	0
Total Consideration	451,974
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Manufacturing-clinical supplies [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	436
Deferred Revenue	34
Total Consideration	470
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Co-development, information sharing & committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	111,693
Deferred Revenue	25,723
Total Consideration	137,416
AstraZeneca Agreements [Member] | U.S./RoW [Member] | China-single unit of accounting [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	0
Deferred Revenue	92,643
Total Consideration	$ 92,643

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 95,366	$ 150,407
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	75,872	126,683
Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	18,251	22,462
Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	207	225
Certificate of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	1,036	1,037
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	641,864	244,950
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	75,872	126,683
Fair Value, Measurements, Recurring [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	18,251	22,462
Fair Value, Measurements, Recurring [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	207	225
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	546,498	94,543
Fair Value, Measurements, Recurring [Member] | Certificate of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	1,036	1,037
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	564,956	117,230
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	18,251	22,462
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	207	225
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	546,498	94,543
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Certificate of deposits [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	76,908	127,720
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	75,872	126,683
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	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 deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	1,036	1,037
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] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, 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 deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 0	$ 0

Fair Value Measurements - Fai27

Fair Value Measurements - Fair Values of Financial Liabilities Carried at Historical Cost (Detail) - Lease financing obligations [Member] - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	$ 98,028	$ 97,856
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	$ 98,028	$ 97,856

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
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

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Cash And Cash Equivalents [Abstract]
Cash	$ 104,875	$ 79,239
Money market funds	546,498	94,543
Total cash and cash equivalents	$ 651,373	$ 173,782	$ 198,283	$ 153,324

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 651,373,000	$ 651,373,000	$ 198,283,000	$ 651,373,000	$ 198,283,000	$ 173,782,000	$ 153,324,000
Contractual maturities of available-for-sale investments	2 years
Other-than-temporary impairment loss		0	$ 0	0	$ 0
Foreign subsidiaries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 19,100,000	$ 19,100,000		$ 19,100,000		$ 24,300,000

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 94,170	$ 150,017
Gross Unrealized Holding Gains	1,212	439
Gross Unrealized Holding Losses	(16)	(49)
Fair Value	95,366	150,407
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	75,826	126,550
Gross Unrealized Holding Gains	62	182
Gross Unrealized Holding Losses	(16)	(49)
Fair Value	75,872	126,683
Certificate of deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,036	1,037
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	1,036	1,037
Bond and mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,182	22,305
Gross Unrealized Holding Gains	1,069	157
Gross Unrealized Holding Losses	0	0
Fair Value	18,251	22,462
Equity investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	126	125
Gross Unrealized Holding Gains	81	100
Gross Unrealized Holding Losses	0	0
Fair Value	$ 207	$ 225

Balance Sheet Components - Sc32

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 26,989	$ 29,550
Payroll and related accruals	14,654	14,232
Professional services	2,144	1,252
Other	10,330	5,880
Total accrued liabilities	$ 54,117	$ 50,914

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Allocated Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 9,628	$ 8,512	$ 27,608	$ 24,256
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	5,538	5,074	16,060	14,629
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 4,090	$ 3,438	$ 11,548	$ 9,627

Stock-Based Compensation - Sc34

Stock-Based Compensation - Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Purchases under 2014 Employee Share Purchase Plan (Detail) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Employee stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 18 days	5 years 3 months 18 days	5 years 8 months 12 days	5 years 3 months 19 days
Expected volatility	69.50%	72.50%	71.50%	69.80%
Risk-free interest rate	1.90%	1.20%	2.20%	1.40%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 26.47	$ 10.73	$ 16.63	$ 11.46
2014 Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	52.80%	63.70%	52.80%	61.90%
Expected volatility, maximum	76.00%	80.70%	77.20%	80.70%
Risk-free interest rate, minimum	0.60%	0.40%	0.50%	0.20%
Risk-free interest rate, maximum	1.30%	0.90%	1.30%	0.90%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 9.67	$ 9.04	$ 9.15	$ 10.27
2014 Employee Share Purchase Plan [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months	6 months
2014 Employee Share Purchase Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	2 years	2 years	2 years	2 years

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Accounts receivable from related party	$ 4,580,000		$ 4,580,000		$ 4,102,000
Accrued liabilities to related parties	479,000		479,000		1,615,000
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	4,600,000	$ 4,800,000	12,900,000	$ 21,800,000
Expense related to collaboration agreements	200,000	$ 1,800,000	800,000	$ 4,800,000
Accounts receivable from related party	4,600,000		4,600,000		4,100,000
Accrued liabilities to related parties	500,000		500,000		1,600,000
Goodwin Procter LLP [Member]
Related Party Transaction [Line Items]
Accrued liabilities to related parties	0		0		$ 0
Goodwin Procter LLP [Member] | Intellectual Property [Member]
Related Party Transaction [Line Items]
Payments for legal matters	$ 0		$ 0

Subsequent Event - Additional I

Subsequent Event - Additional Information (Details) $ in Millions	3 Months Ended
	Dec. 31, 2017USD ($)
AstraZeneca Agreements [Member] | Scenario, Forecast [Member] | China [Member]
Subsequent Event [Line Items]
Milestone payment, revenue recognition	$ 15