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Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

FibroGen, Inc. (“FibroGen” or the “Company”), incorporated in 1993 in Delaware and headquartered in San Francisco, California, with subsidiary offices in Beijing and Shanghai, People’s Republic of China (“China”), is a leading biopharmaceutical company discovering and developing a pipeline of first-in-class therapeutics. The Company applies its pioneering expertise in hypoxia-inducible factor (“HIF”), connective tissue growth factor (“CTGF”) biology, and clinical development to advance innovative medicines for the treatment of anemia, fibrotic disease, and cancer. Roxadustat, the Company’s most advanced product candidate, is an oral small molecule inhibitor of HIF prolyl hydroxylase (“HIF-PH”) activity, completing Phase 3 clinical development worldwide for the treatment of anemia in chronic kidney disease (“CKD”), with a New Drug Application (“NDA”) now approved by the National Medical Products Administration (“NMPA”) in China. The Company and its collaboration partners AstraZeneca AB (“AstraZeneca”) and Astellas Pharma Inc. (“Astellas”) are in the process of preparing an NDA for submission to the United States (“U.S.”) Food and Drug Administration (“FDA”) and a Marketing Authorization Application (“MAA”) for submission to the European Medicines Agency (“EMA”) this year. Astellas submitted an NDA for the treatment of anemia in CKD patients on dialysis in Japan in September 2018, which is currently under review by the Pharmaceuticals and Medical Devices Agency (“PMDA”). Roxadustat is in Phase 3 clinical development in the U.S. and Europe and in Phase 2/3 development in China for anemia associated with myelodysplastic syndromes (“MDS”). Pamrevlumab, an anti-CTGF human monoclonal antibody, is in Phase 3 clinical development for the treatment of idiopathic pulmonary fibrosis (“IPF”), and advancing towards Phase 3 for the treatment of pancreatic cancer. Pamrevlumab is also currently in a Phase 2 trial for Duchenne muscular dystrophy (“DMD”). FibroGen is also developing a biosynthetic cornea in 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 U.S. Securities and Exchange Commission (“SEC”) and, therefore, do not include all information and footnote disclosures normally included in the annual consolidated financial statements. The financial information included herein should be read in conjunction with the consolidated financial statements and related notes in the Company’s Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2018 (“2018 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 2018 Form 10-K, except for the following:

Leases

The Company determines if an arrangement is a lease at inception date when it is given control of the underlying assets. The Company elected the practical expedient not to apply the lease recognition and measurement requirements to short-term leases, which is any lease with a term of 12 months or less as of the commencement date that does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

The Company’s building leases previously accounted for as build-to-suit arrangements prior to the adoption of Accounting Standards Codification (“ASC”) 842 - Leases (“ASC 842”) are accounted for as finance leases under the requirements of ASC 842.

Lease right-of-use (“ROU”) assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As its leases do not typically provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The Company will reassess the incremental borrowing rate periodically for application to any new leases or lease modifications or if any company-specific or general business conditions warrant.

Lease ROU assets include any lease payments made and initial direct costs incurred. The Company has lease agreements with lease and non-lease components. The Company generally accounts for each lease component separately from the non-lease components, and excludes all non-lease components from the calculation of minimum lease payments in measuring the ROU asset and lease liability.

The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease terms.

Regarding leases denominated in a foreign currency, the related ROU assets and the corresponding ROU asset amortization costs are remeasured using the exchange rate in effect at the date of initial recognition; the related lease liabilities are remeasured using the exchange rate in effect at the end of the reporting period; the lease costs and interest expenses related to lease liability accretion are remeasured using average exchange rates for the reporting period.

Finance leases are included in finance lease ROU assets, finance lease liabilities, current and non-current on the Company’s consolidated balance sheets. Operating leases are included in other assets, accrued and other current liabilities, and other long-term liabilities on the Company’s consolidated balance sheets.

Inventories

Inventories are stated at the lower of cost and net realizable value. The cost of inventories are determined using full absorption and standard costing, which approximates cost based on a first-in, first-out method. The Company reviews the standard costs of raw materials, work-in-process and finished goods periodically, and at least annually, to ensure that its inventories approximate current actual costs. The cost of inventories includes direct material costs, direct labor and manufacturing overhead. The Company regularly reviews the need to adjust the carrying value of excess and obsolete inventories to their estimated net realizable value, if less than cost, based primarily on its estimated forecast of product demand and product expiration period.

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 and deferred 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 the Company’s opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of its financial position, results of operations and cash flows for the interim periods presented.

Net Income (Loss) per Share

The following is a reconciliation of the basic and diluted net income (loss) per share calculation for the periods presented (in thousands, except per share data):

	Three Months Ended June 30,					Six Months Ended June 30,
	2019		2018			2019		2018
Net income (loss)	$	116,003	$	(23,421	)	$	70,592	$	(64,817	)
Weighted average shares used to compute net income (loss) per share:
Basic		86,445		83,750			86,077		83,309
Dilutive effect of potential common shares		5,283		—			5,992		—
Diluted		91,728		83,750			92,069		83,309

Net income (loss) per share:
Basic	$	1.34	$	(0.28	)	$	0.82	$	(0.78	)
Diluted	$	1.26	$	(0.28	)	$	0.77	$	(0.78	)

Diluted shares did not include 4.4 million and 3.4 million securities for the three and six months ended June 30, 2019, and 8.8 million and 8.7 million securities for the three and six months ended June 30, 2018, respectively, as they were anti-dilutive.

Recently Issued and Adopted Accounting Guidance

ASC 842

In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842) (“ASU 2016-02”). Under this guidance, an entity is required to recognize ROU assets and lease liabilities on its balance sheet and disclose key information about leasing arrangements. This guidance offers specific accounting guidance for a lessee, a lessor and sale and leaseback transactions. Lessees and lessors are required to disclose qualitative and quantitative information about leasing arrangements to enable a user of the financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements (“ASU 2018-11”), which provides entities the option to initially apply ASU 2016-02 at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption.

The Company adopted the above guidance under ASC 842 as of January 1, 2019, using the modified retrospective transition method, through a cumulative-effect adjustment at the beginning of the first quarter of 2019. The Company elected the optional transition method under the guidance, which allowed it to continue applying previous lease guidance (ASC 840) for the comparative prior year periods presentation in the year of adoption. Accordingly, the Company recognized a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption.

In addition, the Company elected the package of transitional practical expedients permitted under the transition guidance under ASC 842, which among other things allows the Company to carry forward its historical lease classification, and not to reassess initial direct costs for any existing leases. Meanwhile, the Company did not elect the hindsight practical expedient because it has limited number of leases, lease terms are straightforward, and most of its lease renewals are undefined until negotiated.

In addition, the Company has elected the short term accounting policy practical expedient and does not apply the balance sheet recognition requirements for short-term leases (excluding expenses relating to leases with a lease term of one month or less), by class of underlying asset to which the right of use relates. The Company has not elected the non-lease components practical expedient, and therefore accounts for each lease component separately from the non-lease components.

Upon adoption of ASC 842, the Company classified its existing building leases that were previously accounted for as build-to-suit arrangements as finance leases, and applied the transition guidance. Accordingly, the Company derecognized the assets and liabilities previously recognized under ASC 840 build-to-suit guidance. In addition, as a result of applying the transition guidance, the Company also recorded an adjustment to the accumulated depreciation of related leasehold improvements to reflect a change in estimated useful life from the building life to the shorter of the building life and remaining lease term. Differences between the assets and liabilities derecognized were recorded to the opening balance of retained earnings.

The impacts to the select line items from the Company’s condensed consolidated balance sheet upon adoption of the ASC 842 guidance are as follows (in thousands):

Balance Sheet Line Item	Nature of Adjustment	New Lease Guidance Adoption Adjustment
Assets
Property and equipment, net	Derecognition - build-to-suit lease assets - building shell, cost	$	(53,880	)
	Derecognition - build-to-suit lease assets - building shell, accumulated depreciation		13,476
	Change of useful life - leasehold improvements, accumulated depreciation		(38,877	)
Finance lease right-of-use assets	Recognition - finance lease ROU assets		49,597
Other assets	Recognition - operating lease ROU assets		730
Liabilities
Accrued and other current liabilities	Derecognition - deferred rent, current		(619	)
	Derecognition - build-to-suit lease liabilities, current		(545	)
	Recognition - operating lease liabilities, current		404
Finance lease liabilities, current	Recognition - finance lease liabilities, current		11,499
Long-term portion of lease obligations	Derecognition - build-to-suit lease liabilities, non-current		(95,613	)
Deferred rent	Derecognition - deferred rent, non-current		(3,038	)
Finance lease liabilities, non-current	Recognition - finance lease liabilities, non-current		49,884
Other long-term liabilities	Recognition - operating lease liabilities, non-current		250
Stockholders’ equity
Accumulated deficit	Cumulative decrease to accumulated deficit	$	8,688

The adoption of this guidance did not have a material impact to the Company’s condensed consolidated statement of operations or condensed consolidated statement of cash flows for the six months ended June 30, 2019.

ASU 2018-02

In February 2018, the FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This guidance allows for the reclassification from accumulated other comprehensive income to retained earnings for the stranded tax effects arising from the reduction of the U.S. federal statutory income tax rate from 35% to 21%. This guidance was effective for annual reporting period beginning after December 15, 2018, including interim periods. The Company adopted this guidance on January 1, 2019 using the modified retrospective approach. The impacts, based on the aggregate portfolio approach, to the Company’s accumulated other comprehensive loss and accumulated deficit upon adoption of this guidance are as follows (in thousands):

	Accumulated Other Comprehensive Loss			Accumulated Deficit
Balance at December 31, 2018	$	(2,281	)	$	(715,827	)
Impact of change in accounting principle upon adoption of ASU 2018-02		611			(611	)
Opening balance as of January 1, 2019	$	(1,670	)	$	(716,438	)

The adoption of this guidance had no impact to the Company’s condensed consolidated statement of operations or condensed consolidated statement of cash flows for the six months ended June 30, 2019.

SEC Disclosure Requirement

In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, “Disclosure Update and Simplification,” amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders’ equity for interim financial statements. Under the amendments, the changes in each caption of stockholders’ equity presented in the balance sheet must be provided in a note or separate statement. This analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is presented. This final rule was effective as of November 5, 2018. Accordingly, the Company included the condensed consolidated statements of changes in stockholders’ equity in Form 10-Q starting the first quarter of 2019.

ASU 2018-07

In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. This guidance expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The guidance also specifies that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. This guidance was effective for annual reporting period beginning after December 15, 2018, including interim periods. The Company adopted this guidance on January 1, 2019, and the adoption of this guidance had no impact to the Company’s consolidated financial statements.

Recently Issued Accounting Guidance Not Yet Adopted

In August 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. This guidance requires capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). This guidance should be applied either retrospectively or prospectively, and is effective for annual reporting period beginning after December 15, 2019 including interim periods, with early adoption permitted. The Company is currently evaluating the impact on its consolidated financial statements upon the adoption of this guidance.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. This guidance amends existing fair value measurement disclosure requirements by adding, changing, or removing certain disclosures. This guidance is effective for annual reporting period beginning after December 15, 2019 including interim periods, with early adoption permitted. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. The Company does not anticipate a material impact to its consolidated financial statements upon adoption of this guidance.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. Subsequently in April 2019, the FASB issued amendments to the guidance, ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, and in May 2019, ASU 2019-05, Financial Instruments – Credit Losses (Topic 326): Targeted Transition Relief. This guidance requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. The measurement of expected credit losses is based on historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability. ASU 2019-04 clarifies that equity instruments without readily determinable fair values for which an entity has elected the measurement alternative should be remeasured to fair value as of the date that an observable transaction occurred. ASU 2019-05 provides an option to irrevocably elect to measure certain individual financial assets at fair value instead of amortized cost. The amendments should be applied on either a prospective transition or modified-retrospective approach depending on the subtopic. This guidance is effective for the annual reporting period beginning after December 15, 2019, including interim periods within that reporting period. The Company does not anticipate a material impact to its consolidated financial statements upon adoption of this guidance.

Collaboration Arrangements

Astellas Agreements

Japan Agreement

In June 2005, the Company entered into a collaboration agreement with Astellas for the development and commercialization (but not manufacture) of roxadustat for the treatment of anemia in Japan (“Japan Agreement”). Under this agreement, Astellas paid license fees and other consideration totaling $40.1 million (such amounts were fully received as of February 2009). Under the Japan Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $132.5 million in potential milestone payments, comprised of (i) up to $22.5 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of July 2016), (ii) up to $95.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $15.0 million in milestone payments upon the achievement of specified commercial sales milestone. The aggregate amount of such consideration received through June 30, 2019 totals $77.6 million.

Europe Agreement

In April 2006, the Company entered into a separate collaboration agreement with Astellas for the development and commercialization of roxadustat for the treatment of anemia in Europe, the Middle East, the Commonwealth of Independent States and South Africa (“Europe Agreement”). Under the terms of the Europe Agreement, Astellas paid license fees and other upfront consideration totaling $320.0 million (such amounts were fully received as of February 2009). Under the Europe Agreement, the Company is also eligible to receive from Astellas an aggregate of approximately $425.0 million in potential milestone payments, comprised of (i) up to $90.0 million in milestone payments upon achievement of specified clinical and development milestone events (such amounts were fully received as of 2012), (ii) up to $335.0 million in milestone payments upon achievement of specified regulatory milestone events. Under the Europe Agreement, Astellas committed to fund 50% of joint development costs for Europe and North America, and all territory-specific costs. The Europe Agreement also provides for tiered payments based on net sales of product (as defined) in the low 20% range. The aggregate amount of such consideration received through June 30, 2019 totals $410.0 million.

In the fourth quarter of 2018, the Company was engaged in the final stages of review with its partners over the proposed development of roxadustat for the treatment of chemotherapy induced anemia (“CIA”). AstraZeneca and Astellas approved the program in December 2018 and January 2019, respectively. Costs associated with the development of this indication are expected to be shared 50/50 between AstraZeneca and Astellas. For revenue recognition purposes, the Company concluded that this new indication represents a modification to the Europe agreements and will be accounted for separately, meaning the development costs associated with the new indications are distinct from the original development costs. The development service period for roxadustat for the treatment of CIA under the Europe Agreement is estimated to continue through the end of 2023 to allow for development of this indication.

During the second quarter of 2019, the Company received positive topline results from analyses of pooled major adverse cardiac event (“MACE”) and MACE+ data from its Phase 3 trials evaluating roxadustat as a treatment for dialysis and non-dialysis CKD patients, enabling Astellas to prepare for an MAA submission to the EMA during their fiscal year 2019, which ends on March 31, 2020, following the Company’s NDA submission to the FDA. The Company evaluated the two regulatory milestone payments associated with the planned MAA submission and concluded that these milestones became probable of being achieved in the second quarter of 2019. Accordingly, the total consideration of $130.0 million associated with these milestones was included in the transaction price and allocated to performance obligations under the Europe Agreement in the second quarter of 2019, of which $129.5 million was recognized as revenue during the period from performance obligations satisfied or partially satisfied as of June 30, 2019. According to the Europe Agreement, these milestone payments are not billable to Astellas until the submission of an MAA, therefore this $130.0 million was recorded as an unbilled contract asset as of June 30, 2019.

AstraZeneca Agreements

U.S./Rest of World (“RoW”) Agreement

Effective July 30, 2013, the Company entered into a collaboration agreement with AstraZeneca for the development and commercialization of roxadustat for the treatment of anemia in the U.S. and all other countries in the world, other than China, not previously licensed under the Astellas Europe and Astellas Japan Agreements (“U.S./RoW Agreement”). It also excludes China, which is covered by a separate agreement with AstraZeneca described below. Under the terms of the U.S./RoW Agreement, AstraZeneca paid upfront, non-contingent, non-refundable and time-based payments totaling $374.0 million (such amounts were fully received as of June 2016). Under the U.S./RoW Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $875.0 million in potential milestone payments, comprised of (i) up to $65.0 million in milestone payments upon achievement of specified clinical and development milestone events, $15.0 million of which was received in 2015 as a result of the finalization of its two audited pre-clinical carcinogenicity study reports, (ii) up to $325.0 million in milestone payments upon achievement of specified regulatory milestone events, (iii) up to $160.0 million in milestone payments related to activity by potential competitors and (iv) up to approximately $325.0 million in milestone payments upon the achievement of specified commercial sales events. The aggregate amount of such consideration received through June 30, 2019 totals $389.0 million.

As mentioned above, during the second quarter of 2019, the Company received positive topline results from analyses of pooled MACE and MACE+ data from its Phase 3 trials for roxadustat, enabling the Company’s NDA submission to the FDA. The Company evaluated the regulatory milestone payment associated with this planned NDA submission and concluded that this milestone became probable of being achieved in the second quarter of 2019. Accordingly, the consideration of $50.0 million associated with this milestone was included in the transaction price and allocated to performance obligations under the U.S./ RoW Agreement in the second quarter of 2019, of which $41.6 million was recognized as revenue during the period from performance obligations satisfied or partially satisfied as of June 30, 2019. According to the U.S/RoW Agreement, this milestone payment is not billable to AstraZeneca until the Company has submitted the NDA, therefore this $50.0 million was recorded as an unbilled contract asset as of June 30, 2019.

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 paid upfront, non-contingent and non-refundable payments totaling $28.2 million (such amounts were fully received in 2014). Under the China Agreement, the Company is also eligible to receive from AstraZeneca an aggregate of approximately $348.5 million in potential milestone payments, comprised of (i) up to $15.0 million in milestone payments upon achievement of specified clinical and development milestone events, (ii) up to $146.0 million in milestone payments upon achievement of specified regulatory milestone events, and (iii) up to approximately $187.5 million in milestone payments upon the achievement of specified commercial sales and other events. The China Agreement is structured as a 50/50 profit or loss share (as defined) and provides for joint development costs (including capital and equipment costs for construction of the manufacturing plant in China), to be shared equally during the development. The aggregate amount of such consideration received through June 30, 2019 totals $55.2 million.

As mentioned above, in the fourth quarter of 2018, the Company was engaged in the final stages of review with its partners over the proposed development of roxadustat for the treatment of CIA. AstraZeneca and Astellas approved the program in December 2018 and January 2019, respectively. Costs associated with the development of this indication are expected to be shared 50/50 between AstraZeneca and Astellas. In addition to CIA, in December 2018, anemia of chronic inflammation (“ACI”) and multiple myeloma (“MM”) have been approved for development by AstraZeneca and is expected to be fully funded by them. For revenue recognition purposes, the Company concluded that the addition of these new indications represents a modification to the collaboration agreements and will be accounted for separately, meaning the development costs associated with the new indications are distinct from the original development costs. The development service period for roxadustat for the treatment of CIA, ACI and MM under the AstraZeneca agreements is estimated to continue through the end of 2024, to allow for development of these additional indications.

On December 17, 2018, FibroGen (China) Medical Technology Development Co., Ltd. (“FibroGen Beijing”), received marketing authorization from the NMPA for roxadustat, a first-in-class HIF-PH inhibitor, for the treatment of anemia caused by CKD in patients on dialysis. This approval triggered a $6.0 million milestone payable to the Company by AstraZeneca. On December 29, 2018, FibroGen Beijing received First Manufacturing Approval for a Product in the Field in the Territory, which allows production for Phase IV clinical studies, patients’ early experience programs, donation programs, as well as to supply products for testing and assessments required prior to launch. This approval triggered a $6.0 million milestone payable to the Company by AstraZeneca. These milestones payments were received in the first quarter of 2019.

Other Revenues

Other revenues consist primarily of collagen material sold for research purposes. Other revenues were immaterial for all periods presented.

Deferred Revenue

Deferred revenue represents amounts billed, or in certain cases, yet to be billed to the Company’s collaboration partners for which the related revenues have not been recognized because one or more of the revenue recognition criteria have not been met. The current portion of deferred revenue represents the amount to be recognized within one year from the balance sheet date based on the estimated performance period of the underlying performance obligations. The long term portion of deferred revenue represents amounts to be recognized after one year through the end of the non-contingent performance period of the underlying performance obligations.

Deferred revenue includes amounts allocated to the China unit of accounting under the AstraZeneca arrangement as revenue recognition associated with this unit of accounting is tied to the commercial launch of the products within China. As of December 31, 2018, such deferred revenue was included in long-term deferred revenue. As of June 30, 2019, following receipt of the Chinese Good Manufacturing Practices license by FibroGen Beijing in the second quarter of 2019, approximately $0.5 million of the related deferred revenue was included in short-term deferred revenue, which represents the amount of deferred revenue associated with the China unit of accounting that is expected to be recognized as a result of the transfer of control of commercial drug product in China.