FibroGen (FGEN) 10-Q 8 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 31, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
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		62,788,159

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 190,411	$ 153,324
Short-term investments	40,105	27,847
Accounts receivable ($13,365 and $4,455 from a related party)	18,088	15,405
Prepaid expenses and other current assets	3,705	3,988
Total current assets	252,309	200,564
Restricted cash	7,254	7,254
Long-term investments	111,540	131,720
Property and equipment, net	126,264	129,020
Other assets	1,762	2,016
Total assets	499,129	470,574
Current liabilities:
Accounts payable	3,474	6,521
Accrued liabilities ($1,351 and $2,045 to related parties)	47,942	47,932
Deferred revenue	15,027	12,728
Total current liabilities	66,443	67,181
Long-term portion of lease financing obligations	97,395	97,042
Product development obligations	15,515	15,085
Deferred rent	4,461	4,702
Deferred revenue, net of current	97,947	85,132
Other long-term liabilities	4,991	4,607
Total liabilities	286,752	273,749
Commitments and Contingencies	0	0
Stockholders’ equity:
Preferred stock, $0.01 par value; 125,000 shares authorized at June 30, 2016 and December 31, 2015; no shares issued and outstanding at June 30, 2016 and December 31, 2015	0	0
Common stock, $0.01 par value; 225,000 shares authorized at June 30, 2016 and December 31, 2015; 62,742 and 61,985 shares issued and outstanding at June 30, 2016 and December 31, 2015	627	620
Additional paid-in capital	605,089	586,647
Accumulated other comprehensive loss	(1,024)	(1,651)
Accumulated deficit	(411,586)	(408,062)
Total stockholders’ equity	193,106	177,554
Non-controlling interests	19,271	19,271
Total equity	212,377	196,825
Total liabilities, stockholders’ equity and non-controlling interests	$ 499,129	$ 470,574

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Accounts receivable from related party	$ 13,365	$ 4,455
Accrued liabilities to related parties	$ 1,351	$ 2,045
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	62,742,000	61,985,000
Common stock, shares outstanding	62,742,000	61,985,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue:
License and milestone revenue (includes $13,043, $4,860, $16,356 and $9,552 from a related party)	$ 73,197	$ 106,879	$ 92,935	$ 118,385
Collaboration services and other revenue (includes $326, $719, $678 and $1,353 from a related party)	16,083	13,671	24,628	18,463
Total revenue	89,280	120,550	117,563	136,848
Operating expenses:
Research and development	52,392	51,555	96,041	102,094
General and administrative	10,376	9,680	21,794	20,162
Total operating expenses	62,768	61,235	117,835	122,256
Income (loss) from operations	26,512	59,315	(272)	14,592
Interest and other, net
Interest expense	(2,438)	(2,762)	(5,215)	(5,520)
Interest income and other, net	129	707	1,545	1,550
Total interest and other, net	(2,309)	(2,055)	(3,670)	(3,970)
Income (loss) before income taxes	24,203	57,260	(3,942)	10,622
Provision for (benefit from) income taxes	(113)	205	(418)	(66)
Net income (loss)	$ 24,316	$ 57,055	$ (3,524)	$ 10,688
Net income (loss) per share:
Basic	$ 0.39	$ 0.95	$ (0.06)	$ 0.18
Diluted	$ 0.35	$ 0.83	$ (0.06)	$ 0.15
Weighted average number of common shares used to calculate net income (loss) per share:
Basic	62,582	59,798	62,383	59,499
Diluted	69,022	68,752	62,383	69,354

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations (Parenthetical) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
License and milestone revenue from a related party	$ 73,197	$ 106,879	$ 92,935	$ 118,385
Collaboration services and other revenue from a related party	16,083	13,671	24,628	18,463
Astellas Agreement [Member]
License and milestone revenue from a related party	13,043	4,860	16,356	9,552
Collaboration services and other revenue from a related party	$ 326	$ 719	$ 678	$ 1,353

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 24,316	$ 57,055	$ (3,524)	$ 10,688
Other comprehensive income (loss):
Foreign currency translation adjustments	380	508	(262)	2,213
Available-for-sale investments:
Unrealized gain (loss) on investments, net of tax effect	300	(368)	889	343
Reclassification from accumulated other comprehensive loss	0	(25)	0	(30)
Net change in unrealized gain (loss) on available-for-sale investments	300	(393)	889	313
Other comprehensive income, net of taxes	680	115	627	2,526
Comprehensive income (loss)	$ 24,996	$ 57,170	$ (2,897)	$ 13,214

Condensed Consolidated Stateme7

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net income (loss)	$ (3,524)	$ 10,688
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	3,007	2,796
Amortization of premium on investments	1,391	1,538
Unrealized foreign exchange gain on short-term investments	(273)	0
Loss on disposal of property and equipment	0	100
Stock-based compensation	15,744	13,388
Tax benefit on unrealized gain on available-for-sale securities	(479)	(66)
Changes in operating assets and liabilities:
Accounts receivable	(2,683)	1,270
Prepaid expenses and other current assets	283	2,235
Other assets	254	(205)
Accounts payable	(3,047)	(636)
Accrued liabilities	537	(3,140)
Deferred revenue	15,114	30,414
Lease financing liability	554	312
Other long-term liabilities	542	163
Net cash provided by operating activities	27,420	58,857
Investing activities
Purchases of property and equipment	(1,019)	(989)
Purchases of available-for-sale securities	(46)	0
Proceeds from maturities of available-for-sale securities	8,217	7,035
Net cash provided by investing activities	7,152	6,046
Financing activities
Repayments of lease liability	(201)	(201)
Cash paid for payroll taxes on restricted stock unit releases	(1,791)	0
Proceeds from issuance of common stock	4,496	5,608
Net cash provided by financing activities	2,504	5,407
Effect of exchange rate change on cash and cash equivalents	11	771
Net increase in cash and cash equivalents	37,087	71,081
Cash and cash equivalents at beginning of period	153,324	165,455
Cash and cash equivalents at end of period	$ 190,411	$ 236,536

Description of Operations and S

Description of Operations and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
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 in Phase 3 clinical development for the treatment of anemia in chronic kidney disease. Pamrevlumab, or FG-3019, is the Company’s monoclonal antibody in Phase 2 clinical development for the treatment of idiopathic pulmonary fibrosis, pancreatic cancer, Duchenne muscular dystrophy and liver fibrosis. We have taken a global approach with respect to the development and future commercialization of our product candidates, and this includes development and commercialization in the People’s Republic of China (“China”). 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, 2015 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, 2015 ( “2015 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 2015 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 2015 Form 10-K. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. 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 presentation of our financial position, results of operations and cash flows for the interim periods presented. Net Income per Share The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Net income (loss) $ 24,316 $ 57,055 $ (3,524 ) $ 10,688 Weighted average shares used to compute net income per share: Basic 62,582 59,798 62,383 59,499 Dilutive effect of potential common shares 6,440 8,954 - 9,855 Diluted 69,022 68,752 62,383 69,354 Net income (loss) per share: Basic $ 0.39 $ 0.95 $ (0.06 ) $ 0.18 Diluted $ 0.35 $ 0.83 $ (0.06 ) $ 0.15 Diluted shares did not include 6.6 million and 3.8 million securities for the three months ended June 30, 2016 and 2015, and 1.8 million securities for the six months ended June 30, 2015, as they were anti-dilutive. Recently Issued Accounting Guidance Not Yet Adopted In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718) 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 August 2014, the FASB issued ASU 2014-15 , Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern 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): Identifying Performance Obligations and Licensing Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815) Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,

Collaboration Agreements

Collaboration Agreements	6 Months Ended
	Jun. 30, 2016
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 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 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, the last $62.0 million of which was received during the second quarter of 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 the second quarter of 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. 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 June 30, Six Months Ended June 30, Agreement Deliverable 2016 2015 2016 2015 Japan License $ 43 $ 91 $ 118 $ 528 Milestones 10,000 — 10,000 — Total license and milestone revenue 10,043 $ 91 $ 10,118 $ 528 Collaboration services revenue* 3 $ 42 $ 7 $ 100 * 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 June 30, 2016 Deferred Revenue at June 30, 2016 Total Consideration Through June 30, 2016 License $ 42,362 $ — $ 42,362 When and if available compounds 15 27 42 Manufacturing--clinical supplies 1,971 — 1,971 Committee services 17 — 17 Total license and collaboration services revenue $ 44,365 $ 27 $ 44,392 Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Deliverable 2016 2015 2016 2015 Europe License $ 3,000 $ 4,769 $ 6,238 $ 9,024 Milestones — — — — Total license and milestone revenue 3,000 4,769 6,238 9,024 Collaboration services revenue* $ 323 $ 677 $ 671 $ 1,253 * 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 June 30, 2016 Deferred Revenue at June 30, 2016 Total Consideration Through June 30, 2016 License $ 407,554 $ — $ 407,554 When and if available compounds 354 422 776 Manufacturing--clinical supplies 9,762 — 9,762 Development services--in progress 32,654 — 32,654 Committee services 278 4 282 Total license and collaboration services revenue $ 450,602 $ 426 $ 451,028 Amounts recognized as revenue under the U.S./RoW Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Deliverable 2016 2015 2016 2015 U.S. / RoW and China License $ 60,154 $ 87,019 $ 76,579 $ 93,833 Milestones — 15,000 — 15,000 Total license and milestone revenue 60,154 102,019 76,579 108,833 Collaboration services revenue* 15,755 12,942 23,939 17,080 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 June 30, 2016 Deferred Revenue at June 30, 2016 Total Consideration Through June 30, 2016 License $ 366,345 $ — $ 366,345 Co-development, information sharing & committee services 74,006 37,375 111,381 Manufacturing--clinical supplies 327 54 381 China-single unit of accounting — 75,091 75,091 Total license and collaboration services revenue $ 440,678 $ 112,520 $ 553,198 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	6 Months Ended
	Jun. 30, 2016
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): June 30, 2016 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 125,981 $ — $ 125,981 Bond and mutual funds 25,427 — — 25,427 Equity investments 237 — — 237 Money market funds 113,317 — — 113,317 Total $ 138,981 $ 125,981 $ — $ 264,962 December 31, 2015 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 126,103 $ — $ 126,103 Bond and mutual funds 25,052 — — 25,052 Equity investments 197 — — 197 Money market funds 77,639 — — 77,639 Certificate of deposits — 8,215 — 8,215 Total $ 102,888 $ 134,318 $ — $ 237,206 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): June 30, 2016 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 97,798 $ 97,798 December 31, 2015 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 97,445 $ 97,445 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	6 Months Ended
	Jun. 30, 2016
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): June 30, 2016 December 31, 2015 Cash $ 77,094 $ 75,685 Money market funds 113,317 77,639 Total cash and cash equivalents $ 190,411 $ 153,324 At June 30, 2016, a total of $25.6 million 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): June 30, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 125,130 $ 856 $ (5 ) $ 125,981 Bond and mutual funds 25,371 56 — 25,427 Equity investments 125 112 — 237 Total investments $ 150,626 $ 1,024 $ (5 ) $ 151,645 December 31, 2015 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 126,522 $ 54 $ (473 ) $ 126,103 Certificate of deposits 8,217 — (2 ) 8,215 Bond and mutual funds 25,052 — — 25,052 Equity investments 126 71 — 197 Total investments $ 159,917 $ 125 $ (475 ) $ 159,567 At June 30, 2016, all of the available-for-sale investments had contractual maturities within three 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 six months ended June 30, 2016 and 2015, the Company did not recognize any other-than-temporary impairment loss. Accrued Liabilities Accrued liabilities consisted of the following (in thousands): June 30, 2016 December 31, 2015 Preclinical and clinical trial accruals $ 32,054 $ 27,973 Payroll and related accruals 10,285 13,535 Professional services 1,041 1,662 Other 4,562 4,762 Total accrued liabilities $ 47,942 $ 47,932

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2016
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 June 30, Six Months Ended June 30, 2016 2015 2016 2015 Research and development $ 5,059 $ 4,434 $ 9,556 $ 8,656 General and administrative 3,345 2,508 6,188 4,732 Total stock-based compensation expense $ 8,404 $ 6,942 $ 15,744 $ 13,388 The assumptions used to estimate the fair value of stock options granted and ESPPs using the Black-Scholes option valuation model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Stock Options Expected term (in years) 5.3 5.2 5.3 5.2 Expected volatility 72 % 70 % 70 % 70 % Risk-free interest rate 1.3 1.7 1.4 1.7 Expected dividend yield — — — — Weighted average estimated fair value $ 11.60 $ 12.27 $ 11.48 $ 16.68 ESPPs Expected term (in years) 0.5 - 2.0 0.4 - 2.0 0.5 - 2.0 0.4 - 2.0 Expected volatility 61.9 - 80.7% 58.5 - 69.0% 61.9 - 80.7% 58.5 - 69.0% Risk-free interest rate 0.2 - 0.9% 0.1 - 0.6% 0.2 - 0.9% 0.1 - 0.6% Expected dividend yield — — — — Weighted average estimated fair value $ 10.06 $ 13.06 $ 10.98 $ 13.17

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes The benefit from income taxes for the three and six months ended June 30, 2016 was due to the discrete tax effect arising from other comprehensive income related to available-for-sale securities. The provision for income taxes for the three months ended June 30, 2015 was due to the discrete tax effect arising from a change in the valuation of the Company’s available-for-sale securities portfolio. The benefit from income taxes for the six months ended June 30, 2015 was due to the discrete tax effect arising from other comprehensive income related to available-for-sale securities. 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 continue to maintain a full valuation allowance against its deferred tax assets as it does not currently believe that realization of those assets is more likely than not.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2016
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 $13.4 million and $5.6 million during the three months ended June 30, 2016 and 2015, respectively, and of $17.1 million and $10.9 million during the six months ended June 30, 2016 and 2015, respectively. The Company recorded expense related to collaboration agreements with Astellas of $1.4 million and $1.3 million during the three months ended June 30, 2016 and 2015, respectively, and of $3.0 million and $4.4 million during the six months ended June 30, 2016 and 2015, respectively. As of June 30, 2016 and December 31, 2015, accounts receivable from Astellas were $13.4 million and $4.5 million, respectively, and amounts due to Astellas were $1.4 million and $2.0 million, respectively. Julian N. Stern, a director of the Company since November 1996, 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 it as of counsel. The Company retains Goodwin Procter LLP as legal counsel for various matters, primarily consisting of intellectual property matters. During the three and six months ended June 30, 2016, the Company made payments to Goodwin Procter LLP of less than $0.1 million, respectively. During the three and six months ended June 30, 2015, the payments made by the Company to Goodwin Procter LLP were not material. As of June 30, 2016 and December 31, 2015, the balance of accrued liability for Goodwin Proctor LLP was immaterial.

Description of Operations and15

Description of Operations and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
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 in Phase 3 clinical development for the treatment of anemia in chronic kidney disease. Pamrevlumab, or FG-3019, is the Company’s monoclonal antibody in Phase 2 clinical development for the treatment of idiopathic pulmonary fibrosis, pancreatic cancer, Duchenne muscular dystrophy and liver fibrosis. We have taken a global approach with respect to the development and future commercialization of our product candidates, and this includes development and commercialization in the People’s Republic of China (“China”).
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, 2015 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, 2015 ( “2015 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 2015 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 2015 Form 10-K.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. 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 presentation of our financial position, results of operations and cash flows for the interim periods presented.
Net Income per Share	Net Income per Share The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Net income (loss) $ 24,316 $ 57,055 $ (3,524 ) $ 10,688 Weighted average shares used to compute net income per share: Basic 62,582 59,798 62,383 59,499 Dilutive effect of potential common shares 6,440 8,954 - 9,855 Diluted 69,022 68,752 62,383 69,354 Net income (loss) per share: Basic $ 0.39 $ 0.95 $ (0.06 ) $ 0.18 Diluted $ 0.35 $ 0.83 $ (0.06 ) $ 0.15 Diluted shares did not include 6.6 million and 3.8 million securities for the three months ended June 30, 2016 and 2015, and 1.8 million securities for the six months ended June 30, 2015, as they were anti-dilutive.
Recently Issued Accounting Guidance Not Yet Adopted	Recently Issued Accounting Guidance Not Yet Adopted In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718) 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 August 2014, the FASB issued ASU 2014-15 , Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern 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): Identifying Performance Obligations and Licensing Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815) Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,

Description of Operations and16

Description of Operations and Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Schedule of Reconciliation of Basic and Diluted Net Income (Loss) per Share Calculation	The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Net income (loss) $ 24,316 $ 57,055 $ (3,524 ) $ 10,688 Weighted average shares used to compute net income per share: Basic 62,582 59,798 62,383 59,499 Dilutive effect of potential common shares 6,440 8,954 - 9,855 Diluted 69,022 68,752 62,383 69,354 Net income (loss) per share: Basic $ 0.39 $ 0.95 $ (0.06 ) $ 0.18 Diluted $ 0.35 $ 0.83 $ (0.06 ) $ 0.15

Collaboration Agreements (Table

Collaboration Agreements (Tables)	6 Months Ended
	Jun. 30, 2016
Japan [Member]
Summary of Revenue Recognized under Agreement	Three Months Ended June 30, Six Months Ended June 30, Agreement Deliverable 2016 2015 2016 2015 Japan License $ 43 $ 91 $ 118 $ 528 Milestones 10,000 — 10,000 — Total license and milestone revenue 10,043 $ 91 $ 10,118 $ 528 Collaboration services revenue* 3 $ 42 $ 7 $ 100 * 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 June 30, 2016 Deferred Revenue at June 30, 2016 Total Consideration Through June 30, 2016 License $ 42,362 $ — $ 42,362 When and if available compounds 15 27 42 Manufacturing--clinical supplies 1,971 — 1,971 Committee services 17 — 17 Total license and collaboration services revenue $ 44,365 $ 27 $ 44,392
Europe [Member]
Summary of Revenue Recognized under Agreement	Amounts recognized as revenue under the Europe Agreement were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, Agreement Deliverable 2016 2015 2016 2015 Europe License $ 3,000 $ 4,769 $ 6,238 $ 9,024 Milestones — — — — Total license and milestone revenue 3,000 4,769 6,238 9,024 Collaboration services revenue* $ 323 $ 677 $ 671 $ 1,253 * 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 June 30, 2016 Deferred Revenue at June 30, 2016 Total Consideration Through June 30, 2016 License $ 407,554 $ — $ 407,554 When and if available compounds 354 422 776 Manufacturing--clinical supplies 9,762 — 9,762 Development services--in progress 32,654 — 32,654 Committee services 278 4 282 Total license and collaboration services revenue $ 450,602 $ 426 $ 451,028
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 June 30, Six Months Ended June 30, Agreement Deliverable 2016 2015 2016 2015 U.S. / RoW and China License $ 60,154 $ 87,019 $ 76,579 $ 93,833 Milestones — 15,000 — 15,000 Total license and milestone revenue 60,154 102,019 76,579 108,833 Collaboration services revenue* 15,755 12,942 23,939 17,080 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 June 30, 2016 Deferred Revenue at June 30, 2016 Total Consideration Through June 30, 2016 License $ 366,345 $ — $ 366,345 Co-development, information sharing & committee services 74,006 37,375 111,381 Manufacturing--clinical supplies 327 54 381 China-single unit of accounting — 75,091 75,091 Total license and collaboration services revenue $ 440,678 $ 112,520 $ 553,198

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2016
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): June 30, 2016 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 125,981 $ — $ 125,981 Bond and mutual funds 25,427 — — 25,427 Equity investments 237 — — 237 Money market funds 113,317 — — 113,317 Total $ 138,981 $ 125,981 $ — $ 264,962 December 31, 2015 Level 1 Level 2 Level 3 Total Corporate bonds $ — $ 126,103 $ — $ 126,103 Bond and mutual funds 25,052 — — 25,052 Equity investments 197 — — 197 Money market funds 77,639 — — 77,639 Certificate of deposits — 8,215 — 8,215 Total $ 102,888 $ 134,318 $ — $ 237,206
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): June 30, 2016 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 97,798 $ 97,798 December 31, 2015 Level 1 Level 2 Level 3 Total Lease financing obligations $ — $ — $ 97,445 $ 97,445

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): June 30, 2016 December 31, 2015 Cash $ 77,094 $ 75,685 Money market funds 113,317 77,639 Total cash and cash equivalents $ 190,411 $ 153,324
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): June 30, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 125,130 $ 856 $ (5 ) $ 125,981 Bond and mutual funds 25,371 56 — 25,427 Equity investments 125 112 — 237 Total investments $ 150,626 $ 1,024 $ (5 ) $ 151,645 December 31, 2015 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Corporate bonds $ 126,522 $ 54 $ (473 ) $ 126,103 Certificate of deposits 8,217 — (2 ) 8,215 Bond and mutual funds 25,052 — — 25,052 Equity investments 126 71 — 197 Total investments $ 159,917 $ 125 $ (475 ) $ 159,567
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): June 30, 2016 December 31, 2015 Preclinical and clinical trial accruals $ 32,054 $ 27,973 Payroll and related accruals 10,285 13,535 Professional services 1,041 1,662 Other 4,562 4,762 Total accrued liabilities $ 47,942 $ 47,932

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, Six Months Ended June 30, 2016 2015 2016 2015 Research and development $ 5,059 $ 4,434 $ 9,556 $ 8,656 General and administrative 3,345 2,508 6,188 4,732 Total stock-based compensation expense $ 8,404 $ 6,942 $ 15,744 $ 13,388
Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Employee Stock Purchase Plans	The assumptions used to estimate the fair value of stock options granted and ESPPs using the Black-Scholes option valuation model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Stock Options Expected term (in years) 5.3 5.2 5.3 5.2 Expected volatility 72 % 70 % 70 % 70 % Risk-free interest rate 1.3 1.7 1.4 1.7 Expected dividend yield — — — — Weighted average estimated fair value $ 11.60 $ 12.27 $ 11.48 $ 16.68 ESPPs Expected term (in years) 0.5 - 2.0 0.4 - 2.0 0.5 - 2.0 0.4 - 2.0 Expected volatility 61.9 - 80.7% 58.5 - 69.0% 61.9 - 80.7% 58.5 - 69.0% Risk-free interest rate 0.2 - 0.9% 0.1 - 0.6% 0.2 - 0.9% 0.1 - 0.6% Expected dividend yield — — — — Weighted average estimated fair value $ 10.06 $ 13.06 $ 10.98 $ 13.17

Description of Operations and21

Description of Operations and Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016shares	Jun. 30, 2015shares	Jun. 30, 2016Segment	Jun. 30, 2015shares
Accounting Policies [Abstract]
Number of operating segment | Segment			1
Anti-dilutive securities excluded from computation of diluted net income per share | shares	6.6	3.8		1.8

Description of Operations and22

Description of Operations and Summary of Significant Accounting Policies - Schedule of Reconciliation of Basic and Diluted Net Income (Loss) per Share Calculation (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net income (loss)	$ 24,316	$ 57,055	$ (3,524)	$ 10,688
Weighted average shares used to compute net income per share:
Basic	62,582	59,798	62,383	59,499
Dilutive effect of potential common shares	6,440	8,954	0	9,855
Diluted	69,022	68,752	62,383	69,354
Net income (loss) per share:
Basic	$ 0.39	$ 0.95	$ (0.06)	$ 0.18
Diluted	$ 0.35	$ 0.83	$ (0.06)	$ 0.15

Collaboration Agreements - Aste

Collaboration Agreements - Astellas Agreements - Additional Information (Detail) - Astellas Agreement [Member] - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended			35 Months Ended	45 Months Ended
	Apr. 30, 2006	Jun. 30, 2005	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	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			$ 10,000	$ 0	$ 10,000	$ 0
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 Millions	Jul. 30, 2013	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Jun. 30, 2016
U.S./RoW [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected upfront, non-contingent and time-based payments	$ 374
Upfront, non-contingent and time-based payments received		$ 62
Development and regulatory approval milestones	550
Commercial sales milestone	325
Shared development costs			$ 233
Additional consideration based on net sales description					Low 20% range
U.S./RoW [Member] | FibroGen, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Shared development costs			$ 116.5
U.S./RoW [Member] | Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receipt of development milestone payment				$ 15
China [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development and regulatory approval milestones	161
Commercial sales milestone	167.5
Proceeds from upfront payments	28.2
Contingent payment	$ 20

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Revenue Recognized under Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total license and milestone revenue	$ 73,197	$ 106,879	$ 92,935	$ 118,385
Collaboration services and other revenue from a related party	16,083	13,671	24,628	18,463
Revenue recognized	89,280	120,550	117,563	136,848
Astellas Agreement [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Total license and milestone revenue	13,043	4,860	16,356	9,552
Collaboration services and other revenue from a related party	326	719	678	1,353
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
License revenue	43	91	118	528
Milestones revenue	10,000	0	10,000	0
Total license and milestone revenue	10,043	91	10,118	528
Collaboration services and other revenue from a related party	3	42	7	100
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
License revenue	3,000	4,769	6,238	9,024
Milestones revenue	0	0	0	0
Total license and milestone revenue	3,000	4,769	6,238	9,024
Collaboration services and other revenue from a related party	323	677	671	1,253
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	60,154	87,019	76,579	93,833
Milestones revenue	0	15,000	0	15,000
Total license and milestone revenue	60,154	102,019	76,579	108,833
Collaboration services and other revenue from a related party	$ 15,755	$ 12,942	$ 23,939	$ 17,080

Collaboration Agreements - Tota

Collaboration Agreements - Total Arrangement Consideration Allocated to Deliverables along with Associated Deferred Revenue (Detail) $ in Thousands	Jun. 30, 2016USD ($)
Astellas Agreement [Member] | Japan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	$ 44,365
Deferred Revenue	27
Total Consideration	44,392
Astellas Agreement [Member] | Japan [Member] | License [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	42,362
Deferred Revenue	0
Total Consideration	42,362
Astellas Agreement [Member] | Japan [Member] | When and if available compounds [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	15
Deferred Revenue	27
Total Consideration	42
Astellas Agreement [Member] | Japan [Member] | Manufacturing-clinical supplies [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	1,971
Deferred Revenue	0
Total Consideration	1,971
Astellas Agreement [Member] | Japan [Member] | Committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	17
Deferred Revenue	0
Total Consideration	17
Astellas Agreement [Member] | Europe [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	450,602
Deferred Revenue	426
Total Consideration	451,028
Astellas Agreement [Member] | Europe [Member] | License [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	407,554
Deferred Revenue	0
Total Consideration	407,554
Astellas Agreement [Member] | Europe [Member] | When and if available compounds [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	354
Deferred Revenue	422
Total Consideration	776
Astellas Agreement [Member] | Europe [Member] | Manufacturing-clinical supplies [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	9,762
Deferred Revenue	0
Total Consideration	9,762
Astellas Agreement [Member] | Europe [Member] | Committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	278
Deferred Revenue	4
Total Consideration	282
Astellas Agreement [Member] | Europe [Member] | Development services-in progress [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	32,654
Deferred Revenue	0
Total Consideration	32,654
AstraZeneca Agreements [Member] | U.S./RoW [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	440,678
Deferred Revenue	112,520
Total Consideration	553,198
AstraZeneca Agreements [Member] | U.S./RoW [Member] | License [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	366,345
Deferred Revenue	0
Total Consideration	366,345
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Manufacturing-clinical supplies [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	327
Deferred Revenue	54
Total Consideration	381
AstraZeneca Agreements [Member] | U.S./RoW [Member] | Co-development, information sharing & committee services [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Revenue	74,006
Deferred Revenue	37,375
Total Consideration	111,381
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	75,091
Total Consideration	$ 75,091

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 151,645	$ 159,567
Total fair value of financial assets	264,962	237,206
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	125,981	126,103
Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	25,427	25,052
Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	237	197
Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	113,317	77,639
Certificate of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		8,215
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	138,981	102,888
Level 1 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Level 1 [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	25,427	25,052
Level 1 [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	237	197
Level 1 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	113,317	77,639
Level 1 [Member] | Certificate of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	125,981	134,318
Level 2 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	125,981	126,103
Level 2 [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Level 2 [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
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
Level 2 [Member] | Certificate of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		8,215
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Level 3 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 [Member] | Bond and mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 [Member] | Equity investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
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
Level 3 [Member] | Certificate of deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		$ 0

Fair Value Measurements - Fai28

Fair Value Measurements - Fair Values of Financial Liabilities Carried at Historical Cost (Detail) - Lease financing obligations [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities fair value disclosure	$ 97,798	$ 97,445
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	$ 97,798	$ 97,445

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
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	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Cash And Cash Equivalents [Abstract]
Cash	$ 77,094	$ 75,685
Money market funds	113,317	77,639
Total cash and cash equivalents	$ 190,411	$ 153,324	$ 236,536	$ 165,455

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents	$ 190,411,000	$ 190,411,000	$ 236,536,000	$ 190,411,000	$ 236,536,000	$ 153,324,000	$ 165,455,000
Contractual maturities of available-for-sale investments	3 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	$ 25,600,000	$ 25,600,000		$ 25,600,000

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 150,626	$ 159,917
Gross Unrealized Holding Gains	1,024	125
Gross Unrealized Holding Losses	(5)	(475)
Estimated Fair Value	151,645	159,567
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	125,130	126,522
Gross Unrealized Holding Gains	856	54
Gross Unrealized Holding Losses	(5)	(473)
Estimated Fair Value	125,981	126,103
Bond and mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,371	25,052
Gross Unrealized Holding Gains	56	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	25,427	25,052
Equity investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	125	126
Gross Unrealized Holding Gains	112	71
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	$ 237	197
Certificate of deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		8,217
Gross Unrealized Holding Gains		0
Gross Unrealized Holding Losses		(2)
Estimated Fair Value		$ 8,215

Balance Sheet Components - Sc33

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accrued Liabilities Current [Abstract]
Preclinical and clinical trial accruals	$ 32,054	$ 27,973
Payroll and related accruals	10,285	13,535
Professional services	1,041	1,662
Other	4,562	4,762
Total accrued liabilities	$ 47,942	$ 47,932

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Allocated Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 8,404	$ 6,942	$ 15,744	$ 13,388
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	5,059	4,434	9,556	8,656
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,345	$ 2,508	$ 6,188	$ 4,732

Stock-Based Compensation - Sc35

Stock-Based Compensation - Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Employee Stock Purchase Plans (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
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 2 months 12 days	5 years 3 months 18 days	5 years 2 months 12 days
Expected volatility	72.00%	70.00%	70.00%	70.00%
Risk-free interest rate	1.30%	1.70%	1.40%	1.70%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 11.60	$ 12.27	$ 11.48	$ 16.68
Employee stock purchase plans [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	61.90%	58.50%	61.90%	58.50%
Expected volatility, maximum	80.70%	69.00%	80.70%	69.00%
Risk-free interest rate, minimum	0.20%	0.10%	0.20%	0.10%
Risk-free interest rate, maximum	0.90%	0.60%	0.90%	0.60%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average estimated fair value	$ 10.06	$ 13.06	$ 10.98	$ 13.17
Employee stock purchase plans [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months	4 months 24 days	6 months	4 months 24 days
Employee stock purchase plans [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	2 years	2 years	2 years	2 years

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Accounts receivable from related party	$ 13,365,000		$ 13,365,000		$ 4,455,000
Accrued liabilities to related parties	1,351,000		1,351,000		2,045,000
Goodwin Procter LLP [Member] | Intellectual Property [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Payments for legal matters	100,000		100,000
Astellas [Member] | Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Revenue related to collaboration agreements	13,400,000	$ 5,600,000	17,100,000	$ 10,900,000
Expense related to collaboration agreements	1,400,000	$ 1,300,000	3,000,000	$ 4,400,000
Accounts receivable from related party	13,400,000		13,400,000		4,500,000
Accrued liabilities to related parties	$ 1,400,000		$ 1,400,000		$ 2,000,000