0001628280-22-013318 | 10-Q | XBRL Viewer

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Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2022	Apr. 30, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-36352
Entity Registrant Name	AKEBIA THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8756903
Entity Address, Address Line One	245 First Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	871-2098
Title of 12(b) Security	Common Stock, par value $0.00001 per share
Trading Symbol	AKBA
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		183,533,075
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001517022

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 174,562	$ 149,800
Inventory	39,422	38,195
Accounts receivable, net	64,582	50,875
Prepaid expenses and other current assets	24,121	33,140
Total current assets	302,687	272,010
Property and equipment, net	6,451	6,754
Operating lease assets	32,631	33,852
Goodwill	55,053	55,053
Other intangible assets, net	99,116	108,127
Other assets	39,418	49,754
Total assets	535,356	525,550
Current liabilities:
Accounts payable	19,466	33,588
Accrued expenses and other current liabilities	109,660	104,456
Short-term deferred revenue	10,440	20,906
Current portion of refund liability to customer	16,500	0
Current portion of long-term debt	97,848	97,543
Total current liabilities	253,914	256,493
Deferred revenue, net of current portion	65,356	21,474
Operating lease liabilities, net of current portion	32,581	33,703
Derivative liability	1,110	1,820
Liability related to sale of future royalties, net	55,095	53,079
Refund liability to customer, net of current portion	23,441	0
Other non-current liabilities	77,743	82,525
Total liabilities	509,240	449,094
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock $0.00001 par value, 25,000,000 shares authorized; 0 shares issued and outstanding at March 31, 2022 and December 31, 2021	0	0
Common stock $0.00001 par value; 350,000,000 shares authorized at March 31, 2022 and December 31, 2021; 183,386,035 and 177,000,963 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	2	1
Additional paid-in capital	1,548,880	1,536,800
Accumulated other comprehensive loss	6	6
Accumulated deficit	(1,522,772)	(1,460,351)
Total stockholders' equity	26,116	76,456
Total liabilities and stockholders' equity	$ 535,356	$ 525,550

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Feb. 22, 2022	Dec. 31, 2021	Jun. 04, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.00001		$ 0.00001
Preferred stock, authorized (in shares)	25,000,000		25,000,000
Preferred stock, issued (in shares)	0		0
Preferred stock, outstanding (in shares)	0		0
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001	$ 0.00001
Common stock, authorized (in shares)	350,000,000		350,000,000	175,000,000
Common stock, issued (in shares)	183,386,035		177,000,963
Common stock, outstanding (in shares)	183,386,035		177,000,963

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Total revenues	$ 61,699	$ 52,304
Cost of goods sold:
Product	22,333	25,595
Amortization of intangibles	9,011	9,011
Total cost of goods sold	31,344	34,606
Operating expenses:
Research and development	43,833	40,611
Selling, general and administrative	44,327	41,328
License expense	688	695
Total operating expenses	88,848	82,634
Operating loss	(58,493)	(64,936)
Other income (expense):
Interest expense	(5,062)	(4,805)
Other income	1,134	161
Net loss	$ (62,421)	$ (69,580)
Net loss per share - basic (in dollars per share)	$ (0.35)	$ (0.45)
Net loss per share - diluted (in dollars per share)	$ (0.35)	$ (0.45)
Weighted-average number of common shares - basic (in shares)	179,599,045	153,820,809
Weighted-average number of common shares - diluted (in shares)	179,599,045	153,820,809
Comprehensive loss:
Net loss	$ (62,421)	$ (69,580)
Other comprehensive loss - unrealized loss on debt securities	0	(4)
Total comprehensive loss	(62,421)	(69,584)
Product revenue, net
Revenues:
Total revenues	41,448	30,408
License, collaboration and other revenue
Revenues:
Total revenues	$ 20,251	$ 21,896

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Unrealized Gain/(Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		148,074,085
Beginning balance at Dec. 31, 2020	$ 247,618	$ 1	$ 1,425,115	$ 13	$ (1,177,511)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs (in shares)		9,228,017
Issuance of common stock, net of issuance costs	29,498	$ 1	29,497
Proceeds from sale of stock under employee stock purchase plan (in shares)		154,276
Proceeds from sale of stock under employee stock purchase plan	367		367
Share-based compensation expense	5,992		5,992
Restricted stock unit vesting (in shares)		1,063,711
Unrealized loss	(4)			(4)
Net loss	(69,580)				(69,580)
Ending balance (in shares) at Mar. 31, 2021		158,520,089
Ending balance at Mar. 31, 2021	$ 213,891	$ 2	1,460,971	9	(1,247,091)
Beginning balance (in shares) at Dec. 31, 2021	177,000,963	177,000,963
Beginning balance at Dec. 31, 2021	$ 76,456	$ 1	1,536,800	6	(1,460,351)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs (in shares)		4,404,600
Issuance of common stock, net of issuance costs	7,178	$ 1	7,177
Proceeds from sale of stock under employee stock purchase plan (in shares)		191,146
Proceeds from sale of stock under employee stock purchase plan	367		367
Share-based compensation expense	4,536		4,536
Restricted stock unit vesting (in shares)		1,789,326
Unrealized loss	0
Net loss	$ (62,421)				(62,421)
Ending balance (in shares) at Mar. 31, 2022	183,386,035	183,386,035
Ending balance at Mar. 31, 2022	$ 26,116	$ 2	$ 1,548,880	$ 6	$ (1,522,772)

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	Mar. 31, 2022	Feb. 22, 2022	Dec. 31, 2021
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001	$ 0.00001

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net loss	$ (62,421)	$ (69,580)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	417	513
Amortization of intangibles	9,011	9,011
Amortization of premium/discount on investments	0	(11)
Non-cash interest expense related to sale of future royalties	2,345	2,162
Non-cash royalty revenue related to sale of future royalties	(329)	(20)
Non-cash interest expense	246	229
Non-cash operating lease expense	(557)	(494)
Fair value step-up of inventory sold or written off	0	21,575
Write-down of inventory	5,344	5,075
Change in excess inventory purchase commitments	(773)	(8,945)
Stock-based compensation	4,536	5,992
Change in fair value of derivative liability	(710)	80
Changes in operating assets and liabilities:
Accounts receivable	(13,707)	(8,380)
Inventory	(5,247)	(19,193)
Prepaid expenses and other current assets	9,019	2,268
Other long-term assets	3,297	1,361
Accounts payable	(7,358)	(4,912)
Accrued expense	4,426	(4,877)
Operating lease liabilities	616	407
Deferred revenue	33,416	(3,007)
Other non-current liabilities	(3,191)	0
Net cash used in operating activities	(21,620)	(70,746)
Investing activities:
Purchase of equipment	(114)	(59)
Proceeds from the maturities of available for sale securities	0	20,000
Net cash (used in) provided by investing activities	(114)	19,941
Financing activities:
Proceeds from sale of future royalties, net	0	44,783
Proceeds from refund liabilities to customers	40,000	0
Proceeds from the issuance of common stock, net of issuance costs	7,178	29,327
Proceeds from the sale of stock under employee stock purchase plan	367	367
Proceeds from the exercise of stock options	0	0
Net cash provided by financing activities	47,545	74,477
Increase in cash, cash equivalents, and restricted cash	25,811	23,672
Cash, cash equivalents, and restricted cash at beginning of the period	151,839	231,132
Cash, cash equivalents, and restricted cash at end of the period	177,650	254,804
Non-cash financing activities
Unpaid offering costs	$ 0	$ 171

Nature of Organization and Operations	3 Months Ended
Nature of Organization and Operations	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Organization and Operations	Nature of Organization and Operations Akebia Therapeutics, Inc., referred to as Akebia or the Company, was incorporated in the State of Delaware in 2007. Akebia is a biopharmaceutical company with the purpose of bettering the lives of people impacted by kidney disease. The Company has one commercial product, Auryxia® (ferric citrate), which is approved by the U.S. Food and Drug Administration, or FDA, and marketed for two indications in the United States: the control of serum phosphorus levels in adult patients with chronic kidney disease, or CKD, on dialysis, or DD-CKD, and the treatment of iron deficiency anemia, or IDA, in adult patients with CKD not on dialysis, or NDD-CKD. Ferric citrate is also approved and marketed in Japan as an oral treatment for IDA in adult patients for the improvement of hyperphosphatemia in such patients with DD-CKD and NDD-CKD under the trade name Riona (ferric citrate hydrate). Vadadustat, the Company’s lead investigational product candidate, is an investigational oral hypoxia-inducible factor prolyl hydroxylase, or HIF-PH, inhibitor designed to mimic the physiologic effect of altitude on oxygen availability. On March 29, 2022, the Company received a complete response letter, or CRL, from the FDA. The CRL provided that the FDA had completed its review of the Company's new drug application, or NDA, for vadadustat for the treatment of anemia due to CKD in adult patients and had determined that it could not approve the NDA in its present form. The Company is discussing the details of the CRL with the Company's collaboration partners. The Company’s collaboration partner, Otsuka Pharmaceutical Co. Ltd., or Otsuka, submitted a Marketing Authorization Application, or MAA, for vadadustat for the treatment of anemia due to CKD in adult patients with DD-CKD and NDD-CKD to the European Medicines Agency, or EMA, in October 2021. Vadadustat is approved in Japan as a treatment for anemia due to CKD in both DD-CKD and NDD-CKD patients under the trade name VafseoTM , and marketed and sold in Japan by Mitsubishi Tanabe Pharma Corporation, or MTPC. In addition, the Company continues to explore additional development opportunities to expand its pipeline and portfolio of novel therapeutics. Since inception, the Company has devoted most of its resources to research and development, including its preclinical and clinical development activities, commercializing Auryxia, and providing general and administrative support for these operations. The Company began recording revenue from the U.S. sales of Auryxia and revenue from sublicensing rights to Auryxia in Japan from the Company’s Japanese partners, Japan Tobacco, Inc. and its subsidiary Torii Pharmaceutical Co., Ltd., collectively JT and Torii, in December 2018. Additionally, following regulatory approval of vadadustat in Japan, the Company began recognizing royalty revenues from MTPC from the sale of Vafseo in August 2020. In February 2021, the Company entered into a royalty interest acquisition agreement with HealthCare Royalty Partners IV, L.P., or HCR, or the Royalty Agreement, whereby the Company sold its right to receive royalties and sales milestones under its Collaboration Agreement with MTPC, or the MTPC Agreement, subject to certain caps and other terms and conditions (see Note 5 for additional information). The Company has not generated a profit to date and may never generate profits from product sales. Vadadustat and the Company’s other potential product candidates are subject to long development cycles, and the Company may be unsuccessful in its efforts to develop, obtain marketing approval for or market vadadustat and its other potential product candidates. If the Company does not successfully commercialize Auryxia, vadadustat, if approved, or any other potential product candidate, it may be unable to achieve profitability. Going Concern The Company’s management completed its going concern assessment in accordance with Accounting Standards Codification, or ASC, 205-40, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, or ASC 205-40. Pursuant to the requirements of ASC 205-40, the Company’s management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, the Company’s management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of the Company’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. As of March 31, 2022, the Company had cash and cash equivalents of approximately $174.6 million. The Company believes that its cash resources will be sufficient to allow the Company to fund its current operating plan through at least the next twelve months from the filing of this Quarterly Report on Form 10-Q. However, the Company's operating plan includes assumptions pertaining to cost avoidance measures and the reduction of overhead costs that would result from the planned amendment of certain contractual arrangements, including with certain supply and collaboration partners, and the reduction of certain infrastructure costs. Therefore, because these cost avoidance initiatives and certain other elements of the Company's operating plan are outside of its control, including the amendment of certain contractual arrangements, including with supply and collaboration partners, and the reduction of certain infrastructure costs, there is uncertainty as to whether the Company's cash resources will be adequate to support its operations for a period through at least the next twelve months from the date of issuance of these financial statements. In addition, on February 18, 2022, the Company and BioPharma Credit PLC, or the Collateral Agent, BPCR Limited Partnership, as a Lender, and BioPharma Credit Investments V (Master) LP, as a Lender, entered into the First Amendment and Waiver, or the First Amendment and Waiver, which amends and waives certain provisions of the Loan Agreement, dated November 11, 2019 (see Note 10). Pursuant to the Loan Agreement, as amended, the Company’s Quarterly Reports on Form 10-Q for the fiscal quarters ending June 30, 2022 and September 30, 2022, and its future Annual Reports on Form 10-K, must not be subject to any qualification as to going concern. If the Company does not satisfy the covenant as to going concern in any of these filings, the Company will be in default under the Loan Agreement. If an event of default occurs and is continuing under the Loan Agreement, the Collateral Agent is entitled to take enforcement action, including acceleration of amounts due under the Loan Agreement, which the Company may not have the available cash resources to repay at such time. There is also uncertainty as to whether or not the Company will meet its quarterly and annual debt covenants under the Loan Agreement. These conditions raise substantial doubt regarding the Company’s ability to continue as a going concern for a period of one year after the date the financial statements are issued. Management’s plans to alleviate the conditions that raise substantial doubt through cost avoidance measures, including amending certain contractual arrangements, and deprioritizing and cancelling certain infrastructure activities for the Company to continue as a going concern for a period of twelve months from the date the financial statements are issued. However, the Company has concluded that the likelihood that its plan to extend its cash runway from one or more of these approaches will be successful, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about our ability to continue as a going concern for a period of at least twelve months from the date of issuance of these financial statements. If conditions that raise substantial doubt regarding the Company's ability to continue as a going concern still exist as of the filing of the Company's Quarterly Report on Form 10-Q for the quarter ending June 30, 2022, the Company will be in default under its Loan Agreement, as amended. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities, other than obligations under the Loan Agreement classified as current, that might result from the outcome of the uncertainties described above.

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S., or GAAP, for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the unaudited condensed consolidated financial statements have been included. Interim results for the three months ended March 31, 2022 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2022 or any other future period. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Management has determined that the Company operates in one segment, which is the business of developing and commercializing novel therapeutics for people with kidney disease. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 filed with the U.S. Securities and Exchange Commission on March 1, 2022, or the 2021 Annual Report on Form 10-K. The significant accounting policies used in preparation of these unaudited condensed consolidated financial statements for the three months ended March 31, 2022 are consistent with those discussed in Note 2 to the consolidated financial statements in the Company’s 2021 Annual Report on Form 10-K and are updated below as necessary. New Accounting Pronouncements – Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments provide optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The Company is currently evaluating its contracts and the optional expedients provided by the new standard. Use of Estimates The preparation of financial statements in conformity with 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 the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: prepaid and accrued research and development expense, operating lease assets and liabilities, derivative liabilities, refund liabilities to customers, other non-current liabilities, including the excess purchase commitment liability, stock-based compensation expense, product and collaboration revenues including various rebates and reserves related to product sales, non-cash interest expense on the liability related to sale of future royalties, inventories, income taxes, intangible assets and goodwill. Although the Company regularly assesses these estimates, actual results could differ materially from these estimates. Changes in estimates are recorded in the period they become known. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances.

Product Revenue and Reserves for Variable Consideration

3 Months Ended

Mar. 31, 2022

Revenue from Contract with Customer [Abstract]

Product Revenue and Reserves for Variable Consideration

To date, the Company’s only source of product revenue has been from the U.S. sales of Auryxia. Total net product revenue was $41.4 million and $30.4 million for the three months ended March 31, 2022 and 2021, respectively. The following table summarizes activity in each of the product revenue allowance and reserve categories for the three months ended March 31, 2022 and 2021 (in thousands):


	Chargebacks and Discounts		Rebates, Fees and other Deductions		Returns		Total
Balance at December 31, 2021	$	1,278	$	26,625	$	475	$	28,378
Current provisions related to sales in current year	2,711		21,324		1,359		25,394
Adjustments related to prior year sales	(132)		779		—		647
Credits/payments made	(2,465)		(22,491)		(1,293)		(26,249)
Balance at March 31, 2022	$	1,392	$	26,237	$	541	$	28,170

Balance at December 31, 2020	$	802	$	39,912	$	649	$	41,363
Current provisions related to sales in current year	3,170		33,643		2,152		38,965
Adjustments related to prior year sales	3		(1,241)		—		(1,238)
Credits/payments made	(2,646)		(29,098)		(1,917)		(33,661)
Balance at March 31, 2021	$	1,329	$	43,216	$	884	$	45,429

Chargebacks, discounts and returns are recorded as a direct reduction of revenue on the unaudited condensed consolidated statement of operations with a corresponding reduction to accounts receivable on the unaudited condensed consolidated balance sheets. Rebates, distribution-related fees, and other sales-related deductions are recorded as a reduction in revenue on the unaudited condensed consolidated statement of operations with a corresponding increase to accrued liabilities or accounts payable on the unaudited condensed consolidated balance sheets.

Accounts receivable, net related to product sales was approximately $27.7 million and $24.6 million as of March 31, 2022 and December 31, 2021, respectively.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

+ Details

License, Collaboration and Other Significant Agreements

3 Months Ended

Mar. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

License, Collaboration and Other Significant Agreements

During the three months ended March 31, 2022 and 2021, the Company recognized the following revenues from its license, collaboration and other significant agreements and had the following deferred revenue balances as of March 31, 2022:


	Three Months Ended March 31,
	2022		2021
License, Collaboration and Other Revenue:	(in thousands)
MTPC Agreement	$	7,962	$	18
Otsuka U.S. Agreement	5,638		13,674
Otsuka International Agreement	5,503		6,972
Total Proportional Performance Revenue	$	19,103	$	20,664
JT and Torii	1,148		1,159
MTPC Other Revenue	—		73
Total License, Collaboration and Other Revenue	$	20,251	$	21,896


	Three Months Ended March 31, 2022
	Short-Term		Long-Term		Total
Deferred Revenue:	(in thousands)
MTPC Agreement	$	—	$	—	$	—
Otsuka U.S. Agreement	6,192		16,087		22,279
Otsuka International Agreement	4,248		5,973		10,221
Vifor Pharma Agreement	—		43,296		43,296
Total	$	10,440	$	65,356	$	75,796

The following table presents changes in the Company’s contract assets and liabilities during the three months ended March 31, 2022 and 2021 (in thousands):


Three Months Ended March 31, 2022	Balance at Beginning of Period		Additions		Deductions		Balance at End of Period
Contract assets:
Accounts receivable(1)	$	19,094	$	19,542	$	(14,320)	$	24,316
Prepaid expenses and other current assets	$	4,309	$	—	$	(339)	$	3,970
Contract liabilities:
Deferred revenue	$	42,380	$	60,514	$	(27,098)	$	75,796
Accounts payable	$	3,171	$	—	$	(2,852)	$	319
Accrued expenses and other current liabilities	$	—	$	—	$	—	$	—

Three Months Ended March 31, 2021
Contract assets:
Accounts receivable(1)	$	3,045	$	6,740	$	(6,246)	$	3,539
Prepaid expenses and other current assets	$	1,722	$	194	$	—	$	1,916
Contract liabilities:
Deferred revenue	$	40,559	$	22,895	$	(25,902)	$	37,552
Accounts payable	$	7,227	$	—	$	(7,227)	$	—
Accrued expenses and other current liabilities	$	10,000	$	—	$	—	$	10,000

(1)Excludes accounts receivable from other services related to clinical and regulatory activities performed by the Company on behalf of MTPC that are not included in the performance obligations identified under the MTPC Agreement as of March 31, 2022 and 2021 and December 31, 2021 and 2020. Also excludes accounts receivable related to amounts due to the Company from product sales which are included in the accompanying unaudited condensed consolidated balance sheet as of March 31, 2022 and December 31, 2021.

During the three months ended March 31, 2022 and 2021, the Company recognized the following revenues as a result of changes in the contract asset and contract liability balances in the respective periods (in thousands):


	Three Months Ended March 31,
Revenue Recognized in the Period from:	2022		2021
Amounts included in deferred revenue at the beginning of the period	$	6,602	$	5,382
Performance obligations satisfied in previous periods	$	—	$	—

Mitsubishi Tanabe Pharma Corporation Collaboration Agreement

Summary of Agreement

On December 11, 2015, the Company and MTPC entered into the MTPC Agreement, providing MTPC with exclusive development and commercialization rights to vadadustat in Japan and certain other Asian countries, collectively, the MTPC Territory. In addition, the Company will supply vadadustat for both clinical and commercial use in the MTPC Territory, subject to MTPC’s option to manufacture commercial drug product in the MTPC Territory. In February 2021, the Company entered into the Royalty Agreement with HCR, whereby the Company sold its right to receive royalties and sales milestones under the MTPC Agreement, subject to certain caps and other terms and conditions (see Note 5 for additional information). A more detailed description of the MTPC Agreement and the Company's evaluation of this agreement under ASC 606 can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The Company identified two performance obligations in connection with its material promises under the MTPC Agreement as follows: (i) License, Research and Clinical Supply Performance Obligation and (ii) Rights to Future Know-How Performance Obligation. The Company allocates the transaction price to each performance obligation based on the Company’s best estimate of the relative standalone selling price. The Company developed a best estimate of the standalone selling price for the Rights to

Future Know-How Performance Obligation primarily based on the likelihood that additional intellectual property covered by the license conveyed will be developed during the term of the arrangement and determined it is immaterial. As such, the Company did not develop a best estimate of standalone selling price for the License, Research and Clinical Supply Performance Obligation and allocated the entire transaction price to this performance obligation. The deliverables associated with the License, Research and Clinical Supply Performance Obligation were satisfied as of June 30, 2018.

As of March 31, 2022, the transaction price was comprised of: (i) the up-front payment of $20.0 million, (ii) the cost for the Phase 2 studies of $20.5 million, (iii) the cost of all clinical supply provided to MTPC for the Phase 3 studies, (iv) $10.0 million in development milestones received, (v) $25.0 million in regulatory milestones received, comprised of $10.0 million relating to the NDA filing in Japan and $15.0 million relating to regulatory approval of vadadustat in Japan, and (vi) $1.6 million in royalties from net sales of Vafseo. As of March 31, 2022, all development milestones and $25.0 million in regulatory milestones have been achieved. No other regulatory milestones have been assessed as probable of being achieved and as a result have been fully constrained. The Company re-evaluates the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. Revenue for the License, Research and Clinical Supply Performance Obligation for the MTPC Agreement is being recognized using a proportional performance method, for which all deliverables have been completed. The Company recognized $0.3 million of revenue and immaterial revenue from MTPC royalties for the three months ended March 31, 2022 and 2021, respectively. As noted above, in February 2021, the Company entered into the Royalty Agreement, whereby the Company sold its right to receive these royalties and sales milestones under the MTPC Agreement, subject to certain caps and other terms and conditions (see Note 5 for additional information). The revenue is classified as license, collaboration and other revenue in the accompanying unaudited condensed consolidated statements of operations and comprehensive loss. As of March 31, 2022, the Company recorded $0.2 million in accounts receivable, no deferred revenue, and no contract assets. There were no asset or liability balances classified as long-term in the unaudited condensed consolidated balance sheet as of March 31, 2022.

Supply of Drug Product to MTPC

In March 2020, in connection with the MTPC Agreement, the Company and MTPC entered into a letter agreement, pursuant to which the Company agreed to supply MTPC with certain vadadustat process validation drug product for commercial use and MTPC agreed to reimburse the Company for certain manufacturing-related expenses. In connection with this arrangement, the Company invoiced the upfront payment of $10.4 million, which it received during the three months ended June 30, 2020. The Company does not recognize revenue under this arrangement until delivery has occurred and risk of loss passes to MTPC. No revenues were recognized during each of the three months ended March 31, 2022 and 2021 for drug product that was delivered during the applicable period. As of March 31, 2022, the Company recorded no accounts receivable, no deferred revenue, $1.9 million in other current liabilities and no other non-current liabilities for drug product that was subject to return by MTPC.

On July 15, 2020, the Company and its collaboration partner MTPC entered into a supply agreement, or the MTPC Supply Agreement. The MTPC Supply Agreement includes the terms and conditions under which the Company will supply vadadustat drug product to MTPC for commercial use in Japan and certain other Asian countries, as contemplated by the MTPC Agreement. A more detailed description of this supply agreement can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The Company recognized $7.6 million and no revenue under the MTPC Supply Agreement during the three months ended March 31, 2022 and 2021, respectively. As of March 31, 2022, the Company recorded $12.9 million in accounts receivable, no deferred revenue, $18.3 million in other current liabilities and $5.0 million in other non-current liabilities.

U.S. Collaboration and License Agreement with Otsuka Pharmaceutical Co. Ltd.

On December 18, 2016, the Company entered into a collaboration and license agreement with Otsuka, or the Otsuka U.S. Agreement. The collaboration is focused on the development and commercialization of vadadustat in the United States. The Company is responsible for leading the development of vadadustat, for which it submitted an NDA to the FDA in March of 2021, and for which it received a CRL in March 2022. The Company will co-commercialize vadadustat in the United States with Otsuka, subject to the approval of vadadustat by the FDA. The Company controls and retains final decision-making authority with respect to certain matters, including U.S. pricing strategy and manufacturing.

Under the terms of the Otsuka U.S. Agreement, the Company granted to Otsuka a co-exclusive, non-sublicensable license under certain intellectual property controlled by the Company solely to perform medical affairs activities and to conduct non-promotional and commercialization activities related to vadadustat in the United States in accordance with the associated plans. The co-exclusive license relates to activities that will be jointly conducted by the Company and Otsuka pursuant to the terms of the Otsuka U.S. Agreement. Additionally, the parties agreed not to promote, market or sell any competing product in the

territory covered by the Otsuka U.S. Agreement. A more detailed description of this collaboration agreement and the Company's evaluation of this agreement under ASC 606 can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The Company has identified three performance obligations in connection with its obligations under the Otsuka U.S. Agreement as follows: (i) License and Development Services Combined (License Performance Obligation); (ii) Rights to Future Intellectual Property (Future IP Performance Obligation) and (iii) Joint Committee Services (Committee Performance Obligation). The Company allocates the transaction price to each performance obligation based on the Company’s best estimate of the relative standalone selling price. The Company developed a best estimate of standalone selling price for the Committee Performance Obligation after considering the nature of the services to be performed and estimates of the associated effort and rates applicable to such services that would be expected to be realized under similar contracts. The Company developed a best estimate of standalone selling price for the Future IP Performance Obligation primarily based on the likelihood that additional intellectual property covered by the license conveyed will be developed during the term of the arrangement. The Company did not develop a best estimate of standalone selling price for the License Performance Obligation due to the following: (i) the best estimates of standalone selling price associated with the Future IP Performance Obligation was determined to be immaterial and (ii) the period of performance and pattern of recognition for the License Performance Obligation and the Committee Performance Obligation was determined to be similar.

The Company re-evaluates the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. The Company determined that under ASC 606, the contract was modified in the second quarter of 2019, when the Company elected to require Otsuka to increase the aggregate percentage of current global development costs it funds under the Otsuka U.S. Agreement and the Otsuka International Agreement, as defined below, from 52.5% to 80%, or the Otsuka Funding Option, and the Company became eligible to receive the Additional Funding (defined below) amount. In connection with the modification, the Company adjusted the transaction price to include the Additional Funding amount as additional variable consideration. The Company constrains the variable consideration to an amount for which a significant revenue reversal is not probable. The Company estimates the additional funding as a result of exercising the Otsuka Funding Option, or the Additional Funding, will total approximately $149.6 million or more, depending on the actual costs incurred toward the current global development plan. The Additional Funding is fully creditable against future payments due to the Company under the arrangement, provided that future payments due to the Company may not be reduced by more than 50% in any calendar year and any remaining creditable amount above 50% in any calendar year will be applied to subsequent future payments until fully credited. As of March 31, 2022, the Additional Funding was $117.4 million.

As of March 31, 2022, the transaction price totaling $514.4 million was comprised of: (i) the up-front payment of $125.0 million, (ii) the cost share payment with respect to amounts incurred by the Company through December 31, 2016 of $33.8 million, and (iii) the estimate of the net cost share consideration to be received of approximately $355.6 million with respect to amounts incurred by the Company subsequent to December 31, 2016.

As of March 31, 2022, the Company is eligible to receive up to $65.0 million in regulatory milestone payments for the first HIF product to achieve the associated event and up to $575 million in commercial milestone payments associated with aggregate sales of licensed products. These future milestones are subject to reduction as a result of the Company's exercise of the Otsuka Funding Option, as described above. As of March 31, 2022, no development or regulatory milestones have been assessed as probable of being reached and thus have been fully constrained.

During the three months ended March 31, 2022 and 2021, the Company recognized revenue totaling approximately $5.6 million and $13.7 million, respectively, with respect to the Otsuka U.S. Agreement. The revenue is classified as collaboration revenue in the accompanying unaudited condensed consolidated statements of operations. As of March 31, 2022, there was approximately $22.3 million of deferred revenue related to the Otsuka U.S. Agreement of which $6.2 million is classified as current and $16.1 million is classified as long-term in the accompanying unaudited condensed consolidated balance sheet based on the performance period of the underlying obligations. Additionally, as of March 31, 2022, there was $9.0 million in accounts receivable and $2.7 million in prepaid expenses and other current assets in the accompanying unaudited condensed consolidated balance sheet. As of December 31, 2021, there was approximately $2.0 million in contract liabilities (included in accounts payable) and $3.0 million in prepaid expenses and other current assets in the consolidated balance sheet.

The Company determined that the medical affairs, commercialization and non-promotional activities elements of the Otsuka U.S. Agreement represent joint operating activities in which both parties are active participants and of which both parties are exposed to significant risks and rewards that are dependent on the success of the activities. Accordingly, the Company is accounting for the joint medical affairs, commercialization and non-promotional activities in accordance with ASC No. 808, Collaborative Arrangements. As a result, the activities conducted pursuant to the medical affairs, commercialization and non-promotional activities plans will be accounted for as a component of the related expense in the period incurred. During the three months ended March 31, 2022 and 2021, the Company incurred approximately $7.6 million and $1.0 million, respectively, of

costs related to the cost-sharing provisions of the Otsuka U.S. Agreement, of which approximately $3.8 million and $0.5 million are reimbursable by Otsuka and recorded as a reduction to research and development expense during the three months ended March 31, 2022 and 2021, respectively. During the three months ended March 31, 2022, Otsuka incurred no costs related to the cost-sharing provisions of the Otsuka U.S. Agreement. During the three months ended March 31, 2021, Otsuka incurred $0.3 million of costs related to the cost-sharing provisions of the Otsuka U.S. Agreement, of which approximately $0.2 million were reimbursable by the Company and recorded as an increase to research and development expense during the three months ended March 31, 2021.

International Collaboration and License Agreement with Otsuka Pharmaceutical Co. Ltd.

On April 25, 2017, the Company entered into a collaboration and license agreement with Otsuka, or the Otsuka International Agreement. The collaboration is focused on the development and commercialization of vadadustat in Europe, Russia, China, Canada, Australia, the Middle East and certain other territories, collectively, the Otsuka International Territory.

Under the terms of the Otsuka International Agreement, the Company granted to Otsuka an exclusive, sublicensable license under certain intellectual property controlled by the Company to develop and commercialize vadadustat and products containing or comprising vadadustat in the Otsuka International Territory. Additionally, under the terms of this agreement, the Company is responsible for leading the development of vadadustat. Otsuka has the sole responsibility, at its own cost, for the commercialization of vadadustat in the Otsuka International Territory, subject to the approval by the relevant regulatory authorities. A more detailed description of this collaboration agreement and the Company's evaluation of this agreement under ASC 606 can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The Company has accounted for the Otsuka International Agreement separately from the collaboration arrangement with Otsuka with respect to the U.S. due to the lack of interrelationship and interdependence of the elements and payment terms within each of the contracts as they relate to the respective territories. Accordingly, the Company has applied the guidance in ASC 606 solely in reference to the terms and conditions of the Otsuka International Agreement, while the Otsuka U.S. Agreement has continued to be accounted for as a discrete agreement in its own right. The Company evaluated the Otsuka International Agreement in accordance with the provisions of ASC 606 and concluded that the contract counterparty, Otsuka, is a customer.

The Company has identified three performance obligations in connection with its obligations under the Otsuka International Agreement as follows: (i) License and Development Services Combined (License Performance Obligation); (ii) Rights to Future Intellectual Property (Future IP Performance Obligation) and (iii) Joint Committee Services (Committee Performance Obligation). The Company allocates the transaction price to each performance obligation based on the Company’s best estimate of the relative standalone selling price. The Company developed a best estimate of standalone selling price for the Committee Performance Obligation after considering the nature of the services to be performed and estimates of the associated effort and rates applicable to such services that would be expected to be realized under similar contracts. The Company developed a best estimate of standalone selling price for the Future IP Performance Obligation primarily based on the likelihood that additional intellectual property covered by the license conveyed will be developed during the term of the arrangement. The Company did not develop a best estimate of standalone selling price for the License Performance Obligation due to the following: (i) the best estimates of standalone selling price associated with the Future IP Performance Obligation was determined to be immaterial and (ii) the period of performance and pattern of recognition for the License Performance Obligation and the Committee Performance Obligation was determined to be similar.

The Company re-evaluates the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. As of March 31, 2022, the transaction price totaling $316.9 million was comprised of: (i) the up-front payment of $73.0 million, (ii) the cost share payment with respect to amounts incurred by the Company during the quarter ended March 31, 2017 of $0.2 million, and (iii) an estimate of the net cost share consideration to be received with respect to amounts incurred by the Company subsequent to March 31, 2017 of $243.7 million.

As of March 31, 2022, the Company is eligible to receive up to $17.0 million in regulatory milestone payments for the licensed HIF product if the Company achieves the associated event within 12 to 24 months of the first HIF product approval. Additionally, the Company is eligible for up to $525.0 million in commercial milestone payments associated with the aggregate sales of all licensed products. As of March 31, 2022, no development or regulatory milestones have been assessed as probable of being reached and thus have been fully constrained.

During the three months ended March 31, 2022 and 2021, the Company recognized revenue totaling approximately $5.5 million and $7.0 million, respectively, with respect to the Otsuka International Agreement. The revenue is classified as collaboration revenue in the accompanying unaudited condensed consolidated statements of operations. As of March 31, 2022, there was

approximately $10.2 million of deferred revenue related to the Otsuka International Agreement of which $4.2 million is classified as current and $6.0 million is classified as long-term in the accompanying unaudited condensed consolidated balance sheet based on the performance period of the underlying obligations. Additionally, as of March 31, 2022, there was $11.3 million in accounts receivable and $1.2 million in prepaid expenses and other current assets in the accompanying unaudited condensed consolidated balance sheet. As of December 31, 2021, there was approximately $0.9 million in contract liabilities (included in accounts payable) and $1.3 million in prepaid expenses and other current assets in the consolidated balance sheet.

Janssen Pharmaceutica NV Research and License Agreement

On February 9, 2017, the Company entered into a Research and License Agreement, or the Janssen Agreement, with Janssen Pharmaceutica NV, or Janssen, a subsidiary of Johnson & Johnson, pursuant to which Janssen granted the Company an exclusive license under certain intellectual property rights to develop and commercialize worldwide certain HIF prolyl hydroxylase targeted compounds. Under the terms of the Janssen Agreement, Janssen granted to the Company a license for a three-year research term to conduct research on the HIF compound portfolio, which research term is now expired. A more detailed description of this collaboration agreement can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

Under the terms of the Janssen Agreement, the Company made an upfront payment of $1.0 million in cash to Janssen and issued a warrant, or the Warrant, to purchase 509,611 shares of the Company’s common stock, which expired on February 9, 2022. In addition, Janssen could be eligible to receive up to an aggregate of $16.5 million from the Company in specified development milestone payments on a product-by-product basis. Janssen could also be eligible to receive up to $215.0 million from the Company in specified commercial milestones as well as tiered, escalating royalties ranging from a low- to mid-single digit percentage of net sales, on a product-by-product basis, and subject to reduction upon expiration of patent rights or the launch of a generic product in the territory. A more detailed description of this collaboration agreement can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

Cyclerion Therapeutics License Agreement

On June 4, 2021, the Company entered into a License Agreement, the Cyclerion Agreement, with Cyclerion Therapeutics Inc., or Cyclerion, pursuant to which Cyclerion granted the Company an exclusive global license under certain intellectual property rights to research, develop and commercialize praliciguat, an investigational oral soluble guanylate stimulator.

Under the terms of the Cyclerion Agreement, the Company made an upfront payment of $3.0 million in cash to Cyclerion, which was paid during the second quarter of 2021 and recorded to research and development expense in June 2021. Substantially all of the fair value of the assets acquired in conjunction with the Cyclerion Agreement was concentrated in the acquired license. As a result, the Company accounted for this transaction as an asset acquisition under ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The upfront payment was charged to expense at acquisition, as it relates to a development stage compound with no alternative future use. In addition, Cyclerion is eligible to receive up to an aggregate of $222.0 million from the Company in specified development and regulatory milestone payments on a product-by-product basis. Cyclerion will also be eligible to receive specified commercial milestones as well as tiered royalties ranging from a low-single-digit- to mid-double-digit percentage of net sales, on a product-by-product basis, and subject to reduction upon expiration of patent rights or the launch of a generic product in the territory. A more detailed description of this agreement can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

Vifor Pharma License Agreement

Summary of Agreement

On May 12, 2017, the Company entered into a License Agreement, or the Vifor Agreement, with Vifor (International) Ltd., or Vifor Pharma, pursuant to which the Company granted Vifor Pharma an exclusive license to sell vadadustat solely to Fresenius Kidney Care Group LLC, or FKC, an affiliate of Fresenius Medical Care North America, or FMCNA, in the United States. On April 8, 2019, the Company and Vifor Pharma entered into an Amended and Restated License Agreement, or the Vifor First Amended Agreement, which amended and restated in full the Vifor Agreement. On February 18, 2022, the Company and Vifor Pharma entered into a Second Amended and Restated License Agreement, or the Vifor Second Amended Agreement, which amends and restates the Vifor First Amended Agreement.

Pursuant to the Vifor Second Amended Agreement, the Company granted Vifor Pharma an exclusive license to sell vadadustat to Fresenius Medical Care North America and its affiliates, including Fresenius Kidney Care Group LLC, to certain third party dialysis organizations approved by the Company, to independent dialysis organizations that are members of certain group

purchasing organizations, and to certain non-retail specialty pharmacies, or collectively, the Supply Group, in the United States, or the Territory. Pursuant to the Vifor Second Amended Agreement, Vifor Pharma agreed that it would not sell or otherwise supply vadadustat until the FDA has granted regulatory approval for vadadustat in the DD-CKD Indication in the Territory and until Vifor Pharma has entered a supply agreement with the applicable member of the Supply Group.

Similar to the Vifor First Amended Agreement, the Vifor Second Amended Agreement is structured as a profit share arrangement between the Company and Vifor Pharma in which the Company will receive approximately 66% of the profit, net of certain pre-specified costs. Under the Vifor Second Amended Agreement, Vifor Pharma made an upfront payment to the Company of $25.0 million in lieu of the previously disclosed milestone payment of $25.0 million that Vifor Pharma was to pay the Company following approval of vadadustat by the FDA, as established under the Vifor First Amended Agreement.

Unless earlier terminated, the Vifor Second Amended Agreement will expire upon the later of the expiration of all patents that claim or cover vadadustat or expiration of marketing or regulatory exclusivity for vadadustat in the Territory. Vifor Pharma may terminate the Vifor Second Amended Agreement in its entirety upon 30 months' prior written notice after the first anniversary of the receipt of regulatory approval, if approved from the FDA for vadadustat for dialysis-dependent CKD patients. The Company may terminate the Vifor Second Amended Agreement in its entirety for convenience, following the earlier of a certain period of time elapsing or following certain specified regulatory events, and upon six months’ prior written notice. If the Company so terminates for convenience, subject to specified exceptions, the Company will pay a termination fee to Vifor Pharma. In addition, either party may, subject to a cure period, terminate the Vifor Second Amended Agreement in the event of the other party’s uncured material breach or bankruptcy. Vifor Pharma may also terminate the Vifor Second Amended Agreement upon thirty days' notice following receipt of the CRL from the FDA for vadadustat.

Investment Agreement

In connection with the Vifor Agreement, in May 2017, the Company and Vifor Pharma entered into an investment agreement, or the First Investment Agreement, pursuant to which the Company sold an aggregate of 3,571,429 shares of the Company’s common stock, or the 2017 Shares, to Vifor Pharma at a price per share of $14.00 for a total of $50.0 million. The amount representing the premium over the closing stock price of $12.69 on the date of the transaction, totaling $4.7 million, was determined by the Company to represent consideration related to the Vifor Agreement.

Vifor Pharma agreed to a lock-up restriction such that it agreed not to sell the 2017 Shares for a period of time following the effective date of the First Investment Agreement as well as a customary standstill agreement. In addition, the First Investment Agreement contains voting agreements made by Vifor Pharma with respect to the 2017 Shares. The 2017 Shares have not been registered pursuant to the Securities Act of 1933, as amended, or the Securities Act, and were issued and sold in reliance upon the exemption from registration contained in Section 4(a)(2) of the Securities Act and Rule 506 promulgated thereunder.

In connection with entering into the Vifor Second Amended Agreement, on February 18, 2022, the Company and Vifor Pharma entered into an investment agreement, or the Second Investment Agreement, pursuant to which the Company sold an aggregate of 4,000,000 shares of its common stock, par value $0.00001 per share, or the 2022 Shares, to Vifor Pharma for a total of $20 million on February 22, 2022. The amount representing the premium over the grant date fair value on the date of the transaction, $13.6 million, was determined by the Company to represent the consideration related to the Vifor Second Amended Agreement. Vifor Pharma has agreed to a lock-up restriction to not sell or otherwise dispose of the 2022 Shares for a period of time following the effective date of the Second Investment Agreement as well as a customary standstill agreement. In addition, the Second Investment Agreement contains voting agreements made by Vifor Pharma with respect to the 2022 Shares. The 2022 Shares have not been registered pursuant to the Securities Act and were issued and sold in reliance upon the exemption from registration contained in Section 4(a)(2) of the Securities Act and/or Rule 506 promulgated thereunder, as the transaction does not involve any public offering within the meaning of Section 4(a)(2) of the Securities Act.

Revenue Recognition

The Company evaluated the elements of the Vifor Second Amended Agreement in accordance with the provisions of ASC 606 and concluded that the contract counterparty, Vifor Pharma, is a customer. The Company’s arrangement with Vifor Pharma contains one material promise under the contract at inception, which is the non-sublicensable, non-transferrable license under certain of the Company’s intellectual property to (i) sell vadadustat solely to the Supply Group, (ii) sell vadadustat to Designated Wholesalers solely for resale to members of the Supply Group, (iii) conduct medical affairs with respect to vadadustat in the Territory in the field during the term of the Vifor Second Amended Agreement and (iv) use the Akebia Trademark solely in connection with the sale of vadadustat (the License Deliverable).

The Company has identified one performance obligation in connection with its obligations under the Vifor Second Amended Agreement, which is the License Deliverable, or License Performance Obligation. The transaction price at inception was comprised of: (i) the up-front payment of $25.0 million, (ii) the premium on paid by Vifor Pharma on the First Investment Agreement of $4.7 million, and (iii) the premium paid by Vifor Pharma on the Second Investment Agreement of $13.6 million. Pursuant to the terms of the Vifor Second Amended Agreement, these payments from Vifor Pharma are non-refundable and non-creditable against any other amount due to the Company. Also pursuant to the Vifor Second Amended Agreement, if the Centers for Medicare & Medicaid Services, or CMS, determines that vadadustat is excluded from the Transitional Drug Add-on Payment Adjustment, or TDAPA, the Company can terminate the Vifor Second Amended Agreement and will be required to repay the up-front payment and the premiums paid by Vifor Pharma in the First Investment Agreement and Second Investment Agreement, respectively. The Company considered whether the transaction price was constrained as required per the guidance in ASC 606-10-32-11. As part of its evaluation of the constraint, the Company considered numerous factors, including the CRL received from the FDA for vadadustat, the uncertainty associated with a potential future approval of vadadustat by the FDA, and if approval of vadadustat is received in the future, whether vadadustat would be included in certain reimbursement bundles by CMS, which are all outside of the Company’s control. Vifor Pharma also agreed that it will not sell or otherwise supply vadadustat until the FDA has granted regulatory approval for vadadustat in the DD-CKD Indication. The Company constrains the variable consideration to an amount for which a significant revenue reversal is not probable. Therefore, the Company determined that the entire transaction price at inception was constrained under ASC 606, and the Company has recorded the transaction price to deferred revenue as of March 31, 2022.

Refund Liability to Customer

Pursuant to the Vifor Second Amended Agreement, Vifor Pharma contributed $40.0 million to a working capital fund established to partially fund the Company’s costs of purchasing vadadustat from its contract manufacturers, or the Working Capital Fund, which amount of funding will fluctuate, and which funding the Company will repay to Vifor over time. The $40 million initial contribution to the Working Capital Fund represents 50% of the amount of purchase orders that the Company has placed with its contract manufacturers for the supply of vadadustat for the Territory already delivered as of the effective date of the Vifor Second Amended Agreement, and to be delivered through the end of 2022. The amount of the Working Capital Fund will be reviewed at specified intervals and is adjusted based on a number of factors including outstanding supply commitments for vadadustat for the Territory and agreed upon vadadustat inventory levels held by the Company for the Territory. Upon termination or expiration of the Vifor Second Amended Agreement for any reason other than convenience by Vifor Pharma (including following receipt of a CRL for vadadustat), the Company will be required to refund the outstanding balance of the Working Capital Fund on the date of termination or expiration.

The Company has recorded the Working Capital Fund as a refund liability under ASC 606. The Company has determined that the refund liability itself does not represent an obligation to transfer goods or services to Vifor Pharma in the future. The Company has therefore determined that this refund liability is not a contract liability under ASC 606. The Company accounted for the refund liability as a debt arrangement with zero coupon interest. The Company imputed interest on the refund liability to the customer at a rate of 15.0% per annum, which was determined based on certain factors, including the Company's credit rating, comparable securities yield, and the expected repayment period of the Working Capital Fund. The Company recorded an initial discount on the refund liability to the customer and a corresponding deferred gain to the refund liability to customer on the condensed consolidated balance sheet as of the date the funds were received from Vifor Pharma, which was March 18, 2022. The discount on the note payable is being amortized to interest expense using the effective interest method over the expected term of the refund liability. The deferred gain is being amortized to interest income on a straight-line basis over the expected term of the refund liability. The amortization of the discount and the amortization of the deferred gain as of March 31, 2022 were not material. Of the $39.9 million total refund liability, net of deferred gain and discount, the Company classified $16.5 million as a short-term refund liability based on management's estimate of potential amounts that could be refundable within a one-year period as a result of anticipated changes to the Company's operating plan following the CRL.

Priority Review Voucher Letter Agreement

On February 14, 2020, the Company entered into a letter agreement, or the Letter Agreement, with Vifor Pharma relating to Vifor Pharma’s agreement with a third party to purchase a Priority Review Voucher, or the PRV, issued by the FDA, subject to satisfaction of customary closing conditions, or the PRV Purchase. A PRV entitles the holder to priority review of an NDA, or a Biologics License Application for a new drug, which reduces the target FDA review time to six months after official acceptance of the submission, and could lead to expedited approval. Pursuant to the Letter Agreement, Akebia paid Vifor Pharma $10.0 million in connection with the closing of the PRV Purchase.

On August 21, 2021, the Company and Vifor Pharma executed an amendment to the Letter Agreement whereby the parties agreed that Vifor Pharma would sell the PRV to a third party, and the Company and Vifor Pharma would share the proceeds from the sale based on certain terms. In the fourth quarter of 2021, Vifor Pharma sold the PRV to a third party, and Vifor

Pharma paid the Company $8.6 million in proceeds from the sale, which was recorded as contra research and development expense. These proceeds were subsequently paid to Otsuka as reimbursement for their contribution to the purchase of the PRV, as required under a separate letter agreement executed with Otsuka. A more detailed description of this transaction can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

License Agreement with Panion & BF Biotech, Inc.

As a result of the merger with Keryx Biopharmaceuticals, Inc., or Keryx, or the Merger, the Company had a license agreement, which was amended from time to time, with Panion & BF Biotech, Inc., or Panion, under which Keryx, the Company's wholly owned subsidiary, was the contracting party, or the Panion License Agreement, pursuant to which Keryx in-licensed the exclusive worldwide rights, excluding certain Asian-Pacific countries, or the Licensor Territory, for the development and commercialization of ferric citrate.

On April 17, 2019, the Company and Panion entered into a second amended and restated license agreement, or the Panion Amended License Agreement, which amends and restates in full the Panion License Agreement, effective as of April 17, 2019. The Panion Amended License Agreement provides Keryx with an exclusive license under Panion-owned know-how and patents with the right to sublicense, develop, make, use, sell, offer for sale, import and export ferric citrate worldwide, excluding the Licensor Territory. The Panion Amended License Agreement also provides Panion with an exclusive license under the Keryx-owned patents, with the right to sublicense (with the Company’s written consent), develop, make, use, sell, offer for sale, import and export ferric citrate in certain countries in the Licensor Territory. Under the Panion Amended License Agreement, Panion is eligible to receive from the Company or any sublicensee royalty payments based on a mid-single digit percentage of sales of ferric citrate in the Company’s licensed territories. The Company is eligible to receive from Panion or any sublicensee royalty payments based on a mid-single digit percentage of net sales of ferric citrate in Panion’s licensed territories. A more detailed description of this license agreement can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The Company recognized royalty payments due to Panion of approximately $2.5 million during each of the three months ended March 31, 2022 and 2021, relating to the Company’s sales of Auryxia in the United States and JT and Torii’s net sales of Riona in Japan, as the Company is required to pay a mid-single digit percentage of net sales of ferric citrate in the Company’s licensed territories to Panion under the terms of the Panion Amended License Agreement.

Sublicense Agreement with Japan Tobacco, Inc. and its subsidiary, Torii Pharmaceutical Co., Ltd.

As a result of the Merger, the Company has an Amended and Restated Sublicense Agreement, which was amended in June 2013, with JT and Torii, or the JT and Torii Sublicense Agreement, under which Keryx, the Company’s wholly owned subsidiary, remains the contracting party. Under the JT and Torii Sublicense Agreement, JT and Torii obtained the exclusive sublicense rights for the development and commercialization of ferric citrate hydrate in Japan. JT and Torii are responsible for the future development and commercialization costs in Japan. A more detailed description of this sublicense agreement can be found in Note 4 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The Company identified two performance obligations in connection with its obligations under the JT and Torii Sublicense Agreement: (i) License and Supply Performance Obligation and (ii) Rights to Future Know-How Performance Obligation. The Company allocated the transaction price to each performance obligation based on the Company’s best estimate of the relative standalone selling price. The Company developed a best estimate of the standalone selling price for the Rights to Future Know-How Performance Obligation primarily based on the likelihood that additional intellectual property covered by the license conveyed will be developed during the term of the arrangement and determined it immaterial. As such, the Company did not develop a best estimate of standalone selling price for the License and Supply Performance Obligation and allocated the entire transaction price to this performance obligation.

The Company recognized license revenue of $1.1 million and $1.2 million during the three months ended March 31, 2022 and 2021, respectively, related to royalties earned on net sales of Riona in Japan. The Company records the associated mid-single digit percentage of net sales royalty expense due to Panion, the licensor of Riona, in the same period as the royalty revenue from JT and Torii is recorded.

Liability Related to Sale of Future Royalties

3 Months Ended

Mar. 31, 2022

Other Liabilities Disclosure [Abstract]

On February 25, 2021, the Company entered into the Royalty Agreement with HCR, pursuant to which the Company sold to HCR its right to receive royalties and sales milestones for vadadustat in Japan and certain other Asian countries, such countries, collectively, the MTPC Territory, and such payments collectively the Royalty Interest Payments, in each case, payable to the Company under the MTPC Agreement, subject to an annual maximum “cap” of $13.0 million, or the Annual Cap, and an aggregate maximum “cap” of $150.0 million, or the Aggregate Cap. The Company received $44.8 million from HCR (net of certain transaction expenses) under the Royalty Agreement. The Company retains the right to receive all potential future regulatory milestones for vadadustat under the MTPC Agreement. Although the Company sold its right to receive royalties and sales milestones for vadadustat in the MTPC Territory as described above, as a result of its ongoing involvement in the cash flows related to these royalties, the Company will continue to account for these royalties as revenue. The Company recognized the proceeds received from HCR as a liability that is being amortized using the effective interest method over the life of the arrangement. At the transaction date, the Company recorded the net proceeds of $44.8 million as a liability. In order to determine the amortization of the liability, the Company is required to estimate the total amount of future net royalty payments to be made to HCR over the term of the Royalty Agreement. The total threshold of net royalties to be paid, less the net proceeds received, will be recorded as interest expense over the life of the liability. The Company imputes interest on the unamortized portion of the liability using the effective interest method. The annual effective interest rate as of March 31, 2022 was 17.7% which is reflected as interest expense in the unaudited condensed consolidated statements of operations and comprehensive loss. On a quarterly basis, the Company reassesses the effective interest rate and adjusts the rate prospectively as needed. A more detailed description of Royalty Agreement can be found in Note 5 of the Notes to the Consolidated Financial Statements in the 2021 Annual Report on Form 10-K.

The following table shows the activity within the liability account for the three months ended March 31, 2022:


	March 31, 2022
	(in thousands)
Liability related to sale of future royalties, net beginning balance at December 31, 2021	$	53,079
MTPC royalties payable	(329)
Non-cash interest expense recognized	2,345
Liability related to sale of future royalties, net — ending balance	$	55,095

Fair Value of Financial Instruments

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

The Company utilizes a portfolio management company for the valuation of the majority of its investments. This portfolio management company is an independent, third-party vendor recognized to be an industry leader with access to market information that obtains or computes fair market values from quoted market prices, pricing for similar securities, recently executed transactions, cash flow models with yield curves and other pricing models. For valuations obtained from the pricing service, the Company performs due diligence to understand how the valuation was calculated or derived, focusing on the valuation technique used and the nature of the inputs.

Based on the fair value hierarchy, the Company classifies its cash equivalents within Level 1 or Level 2. This is because the Company values its cash equivalents using quoted market prices or alternative pricing sources and models utilizing market observable inputs.

Assets measured or disclosed at fair value on a recurring basis as of March 31, 2022 and December 31, 2021 are summarized below:


	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(in thousands)
March 31, 2022
Assets:
Cash and cash equivalents	$	174,562	$	—	$	—	$	174,562
	$	174,562	$	—	$	—	$	174,562
Liabilities:
Derivative liability	$	—	$	—	$	1,110	$	1,110
	$	—	$	—	$	1,110	$	1,110


	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(in thousands)
December 31, 2021
Assets:
Cash and cash equivalents	$	149,800	$	—	$	—	$	149,800
	$	149,800	$	—	$	—	$	149,800
Liabilities:
Derivative liability	$	—	$	—	$	1,820	$	1,820
	$	—	$	—	$	1,820	$	1,820

The Company’s Loan Agreement with Pharmakon (see Note 10) contains certain provisions that change the underlying cash flows of the debt instrument, including a potential extension to the interest-only period dependent on both (i) no event of default having occurred and continuing and (ii) the Company achieving certain regulatory and revenue conditions. One of the regulatory conditions was approval of vadadustat by August 2022, however, in March 2022, the Company received a CRL from the FDA stating that the FDA had determined that it could not approve the NDA for vadadustat in its present form. Therefore, the Company is no longer eligible for the interest-only extension period and this no longer changes the underlying cash flows of the debt instrument. The Company also assessed the acceleration of the obligations under the Loan Agreement under certain events of default. In addition, under certain circumstances, a default interest rate will apply on all outstanding obligations during the occurrence and continuance of an event of default. In accordance with ASC 815, the Company concluded that these features are not clearly and closely related to the host instrument, and represent a single compound derivative that is required to be re-measured at fair value on a quarterly basis.

The potential events of default assessed include failure to maintain, on an annual basis, a minimum liquidity threshold which started in 2021, and on a quarterly basis, a minimum net sales threshold for Auryxia which started in the fourth quarter of 2020. The Company recorded a derivative liability related to the Company’s Loan Agreement with Pharmakon of $1.1 million and $1.8 million as of March 31, 2022 and December 31, 2021, respectively. The Company classified the derivative liability as a non-current liability on the unaudited condensed consolidated balance sheet as of March 31, 2022 and December 31, 2021. The estimated fair value of the derivative liability on both March 31, 2022 and December 31, 2021 was determined using a scenario-based approach and discounted cash flow model that includes principal and interest payments under various scenarios involving clinical development success for vadadustat and various cash flow assumptions. The Company used a 0% probability of clinical development success due to receipt of a CRL from the FDA for vadadustat. Should the Company’s assessment of the probabilities around these scenarios change, including for changes in market conditions, there could be a change to the fair value of the derivative liability.

The following table provides a roll-forward of the fair value of the derivative liability (in thousands):


Balance at December 31, 2021	$	1,820
Change in fair value of derivative liability, recorded as other expense	(710)
Balance at March 31, 2022	$	1,110

The Company had no other assets or liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) at March 31, 2022 and December 31, 2021.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Inventory

3 Months Ended

Mar. 31, 2022

Inventory Disclosure [Abstract]

Inventory

The components of inventory are summarized as follows:


	March 31, 2022		December 31, 2021
	(in thousands)
Raw materials	$	678	$	1,763
Work in process	74,025		62,635
Finished goods	8,207		14,661
Total inventory	$	82,910	$	79,059

Long-term inventory, which primarily consists of raw materials and work in process, is included in other assets in the Company’s unaudited condensed consolidated balance sheets.


	March 31, 2022		December 31, 2021
	(in thousands)
Balance Sheet Classification:
Inventory	$	39,422	$	38,195
Other assets	43,488		40,864
Total inventory	$	82,910	$	79,059

Inventory amounts written down as a result of excess, obsolescence, scrap or other reasons and charged to cost of goods sold totaled $5.3 million and $5.1 million during the three months ended March 31, 2022 and 2021, respectively. In addition, there were no related step-up charges during the three months ended March 31, 2022 and $8.7 million related step-up charges during the three months ended March 31, 2021. During the three months ended March 31, 2022, the Company recorded a $3.2 million reduction to the excess purchase commitment liability related to Auryxia inventory previously identified as excess, reflecting Auryxia inventory that was received during the period.

If future sales of Auryxia are lower than expected, the Company may be required to write-down the value of such inventories. Inventory write-downs and losses on purchase commitments are recorded as a component of cost of goods sold in the unaudited condensed consolidated statement of operations.

Intangible Assets and Goodwill

3 Months Ended

Mar. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets and Goodwill

Intangible Assets

The following table presents the Company’s intangible assets at March 31, 2022 and December 31, 2021 (in thousands):


	March 31, 2022
	Gross Carrying Value		Accumulated Amortization		Total
Intangible assets:
Developed product rights for Auryxia	$	213,603	$	(114,487)	$	99,116
Total	$	213,603	$	(114,487)	$	99,116


	December 31, 2021
	Gross Carrying Value		Accumulated Amortization		Total
Intangible assets:
Developed product rights for Auryxia	$	213,603	$	(105,476)	$	108,127
Total	$	213,603	$	(105,476)	$	108,127

The Company amortizes its definite-lived intangible assets using the straight-line method, which is considered the best estimate of economic benefit, over its estimated useful life of six years. The Company recorded $9.0 million in amortization expense related to the developed product rights for Auryxia during each of the three months ended March 31, 2022 and 2021.

Goodwill

The Company's goodwill results from the acquisition of Keryx in December 2018. Goodwill was $55.1 million as of March 31, 2022 and December 31, 2021. The Company operates in one operating segment which the Company considers to be the only reporting unit. Goodwill is evaluated for impairment at the reporting unit level on an annual basis as of October 1, and more frequently if indicators are present or changes in circumstances suggest that an impairment may exist. During the first quarter of 2022, the Company evaluated business factors, including the receipt of a CRL from the FDA for vadadustat, to determine if there were events or changes in circumstance to indicate that the fair value of the reporting unit was less than its carrying value. The Company determined that it was not more likely than not that the fair value of the reporting unit was less than its carrying value and, accordingly, determined that there was no impairment of goodwill during the three months ended March 31, 2022.

However, the future occurrence of events including, but not limited to, an adverse change in current economic and market conditions, including a significant prolonged decline in market capitalization, a significant adverse change in legal factors, unexpected adverse business conditions and an adverse action or assessment by a regulator could indicate potential impairment and trigger an interim impairment assessment of goodwill. As a result of the significance of goodwill, the Company's results of operations and financial position in a future period could be negatively impacted should an impairment test be triggered that results in an impairment of goodwill.

Accrued Expenses

3 Months Ended

Mar. 31, 2022

Payables and Accruals [Abstract]

Accrued Expenses

Accrued expenses as of March 31, 2022 and December 31, 2021 are as follows:


	March 31, 2022		December 31, 2021
	(in thousands)
Product revenue allowances	$	26,236	$	26,624
Accrued clinical	16,710		14,036
Amounts due to collaboration partners	28,019		22,654
Accrued payroll and related	7,130		15,863
Lease liability	4,763		4,802
Royalties	3,175		3,472
Professional fees	2,711		1,899
Accrued commercial manufacturing	3,884		3,843
Accrued other	17,032		11,263
Total accrued expenses	$	109,660	$	104,456

Debt	3 Months Ended
Debt	Mar. 31, 2022
Debt Disclosure [Abstract]
Debt	Debt Term Loans On November 11, 2019, the Company, with Keryx as guarantor, entered into a loan agreement, or the Loan Agreement, with BioPharma Credit PLC as collateral agent and a lender, or the Collateral Agent, and BioPharma Credit Investments V (Master) LP as a lender, pursuant to which term loans in an aggregate principal amount of $100.0 million were made available to the Company in two tranches, subject to certain terms and conditions, or the Term Loans. BioPharma Credit PLC subsequently transferred its interest in the Term Loans, solely in its capacity as a lender, to its affiliate, BPCR Limited Partnership. The Collateral Agent and the lenders are collectively referred to as Pharmakon. The first tranche of $80.0 million, or Tranche A, was drawn on November 25, 2019, or the Tranche A Funding Date, and the second tranche of $20.0 million, or Tranche B, was drawn on December 10, 2020, or the Tranche B Funding Date. Each of the Tranche A Funding Date and the Tranche B Funding Date, a Funding Date. Proceeds from the Term Loans may be used for general corporate purposes. The Company and Keryx entered into a Guaranty and Security Agreement with the Collateral Agent, or the Guaranty and Security Agreement, on the Tranche A Funding Date. Pursuant to the Guaranty and Security Agreement, the Company’s obligations under the Term Loans are unconditionally guaranteed by Keryx, or the Guarantee. Additionally, the obligations of the Company and Keryx under the Term Loans and the Guarantee are secured by a first priority lien on certain assets of the Company and Keryx, including Auryxia and certain related assets, cash, and certain equity interests held by the Company and Keryx, collectively the Collateral. The Term Loans bear interest at a floating rate per annum equal to the three-month LIBOR rate plus 7.50%, subject to a 2.00% LIBOR floor and a 3.35% LIBOR cap, payable quarterly in arrears. The Term Loans will mature on the fifth anniversary of the Tranche A Funding Date, or the Maturity Date. The Company will repay the principal under the Term Loans in equal quarterly payments starting on the 33rd-month anniversary of the applicable Funding Date, or the Amortization Schedule. If certain conditions are met, it would have the option to repay the principal in equal quarterly payments starting on the 48th-month anniversary of the applicable Funding Date. One of these conditions was approval of vadadustat; however, the Company received a CRL from the FDA in March 2022 stating that the FDA had determined that it could not approve the NDA in its present form. Therefore, the Company is no longer eligible for this option to delay repayment of the principal under the Loan Agreement. Under certain circumstances, unless certain liquidity conditions are met, the Maturity Date may decrease by up to one year, and the Amortization Schedule may correspondingly commence up to one year earlier. On the Tranche A Funding Date, the Company paid to Pharmakon a facility fee equal to 2.00% of the aggregate principal amount of the Term Loans, or $2.0 million, in addition to other expenses incurred by Pharmakon and reimbursed by the Company, or Lender Expenses. The Tranche A draw was $77.3 million, net of facility fee, Lender Expenses and issuance costs. The Tranche B draw was $20.0 million, net of immaterial Lender Expenses and issuance costs. The Loan Agreement permits voluntary prepayment at any time in whole or in part, subject to a prepayment premium. The prepayment premium would be 2.00% of the principal amount being prepaid prior to the third anniversary of the applicable Funding Date, 1.00% on or after the third anniversary, but prior to the fourth anniversary, of the applicable Funding Date, and 0.50% on or after the fourth anniversary of the applicable Funding Date but prior to the Maturity Date, and a make-whole premium on or prior to the second anniversary of the applicable Funding Date in an amount equal to foregone interest through the second anniversary of the applicable Funding Date. A change of control triggers a mandatory prepayment of the Term Loans. The Loan Agreement contains customary representations, warranties, events of default and covenants of the Company and its subsidiaries, including maintaining, on an annual basis, a minimum liquidity threshold which started in 2021, and on a quarterly basis, a minimum net sales threshold for Auryxia which started in the fourth quarter of 2020. On February 18, 2022, the Loan Agreement was amended, which amendment waived the provision under the Loan Agreement that required the Company to not be subject to any qualification as a going concern within the Company's 2021 Annual Report on Form 10-K. Pursuant to the Loan Agreement, as amended, the Company's filings of Form 10-Q for fiscal quarters ending June 30, 2022 and September 30, 2022, and its future Annual Reports on Form 10-K, must not be subject to any qualification as to going concern. If the Company does not satisfy the covenant as to going concern in any of these filings, the Company will be in default under the Loan Agreement. There is uncertainty as to whether or not the Company will meet its future quarterly and annual debt covenants related to qualification as to going concern. If an event of default occurs and is continuing under the Loan Agreement, the Collateral Agent is entitled to take enforcement action, including acceleration of amounts due under the Loan Agreement. Therefore, as of March 31, 2022, the Company continued to classify the borrowings under the Loan Agreement as current. Under certain circumstances, a default interest rate will apply on all outstanding obligations during the occurrence and continuance of an event of default. As of March 31, 2022 and December 31, 2021, the Company determined that no events of default had occurred. The Company assessed the terms and features of the Loan Agreement in order to identify any potential embedded features that would require bifurcation or any beneficial conversion feature. As part of this analysis, the Company assessed the economic characteristics and risks of the Loan Agreement, including put and call features. The terms and features assessed include a potential extension to the interest-only period dependent on both no event of default having occurred and continuing and the Company achieving certain regulatory and revenue conditions. The Company also assessed the acceleration of the obligations under the Loan Agreement under an event of default. In addition, under certain circumstances, a default interest rate will apply on all outstanding obligations during the occurrence and continuance of an event of default. In accordance with ASC 815, the Company concluded that these features are not clearly and closely related to the host instrument, and represent a single compound derivative that is required to be re-measured at fair value on a quarterly basis. The fair value of the derivative liability related to the Company’s Loan Agreement with Pharmakon was $1.1 million and $1.8 million as of March 31, 2022 and December 31, 2021, respectively. The Company classified the derivative liability as a non-current liability on the unaudited condensed consolidated balance sheet as of March 31, 2022. The Company recognized interest expense related to the Loan Agreement of $2.7 million during each of the three months ended March 31, 2022 and 2021.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

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+ Details

Warrant	3 Months Ended
Warrant	Mar. 31, 2022
Warrants and Rights Note Disclosure [Abstract]
Warrant	WarrantIn connection with the Janssen Agreement, in February 2017, the Company issued a warrant to purchase 509,611 shares of the Company’s common stock at an exercise price of $9.81 per share. The warrant was fully vested upon issuance and exercisable in whole or in part, at any time prior to February 9, 2022. The warrant satisfied the equity classification criteria of ASC 815, and is therefore classified as an equity instrument. The fair value at issuance of $3.4 million was calculated using the Black Scholes option pricing model and was charged to research and development expense as it represented consideration for a license for which the underlying intellectual property was deemed to have no alternative future use. The warrant expired on February 9, 2022.

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2022
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Authorized and Outstanding Capital Stock On June 5, 2020, the Company filed a Certificate of Amendment to its Ninth Amended and Restated Certificate of Incorporation, or its Charter, to increase the number of authorized shares of common stock from 175,000,000 to 350,000,000. As of March 31, 2022, the authorized capital stock of the Company included 350,000,000 shares of common stock, par value $0.00001 per share, of which 183,386,035 and 177,000,963 shares were issued and outstanding as of March 31, 2022 and December 31, 2021, respectively; and 25,000,000 shares of undesignated preferred stock, par value $0.00001 per share, of which no shares were issued and outstanding as of March 31, 2022 and December 31, 2021. At-the-Market Facility On March 12, 2020, the Company filed a prospectus supplement relating to the sales agreement, pursuant to which it was able to offer and sell up to $65.0 million of its common stock at current market prices from time to time. Through December 31, 2020, the Company sold 3,509,381 shares of common stock under this program with net proceeds (after deducting commissions and other offering expenses) of $10.6 million. During the three months ended March 31, 2021, the Company sold 5,224,278 shares of common stock under this program with net proceeds (after deducting commissions and other offering expenses) of $15.9 million. On February 25, 2021, the Company filed a prospectus relating to the sales agreement with its new shelf registration statement (which replaced the prior shelf registration statement and the sales agreement prospectus supplement), pursuant to which it was able to offer and sell up to $100.0 million of its common stock at current market prices from time to time. Through December 31, 2021, the Company sold 21,128,065 shares of common stock under this program with net proceeds (after deducting commissions and other offering expenses) of $72.4 million. On March 1, 2022, the Company filed a prospectus relating to the sales agreement, pursuant to which it was authorized to offer and sell up to $25.3 million of its common stock at current market prices from time to time. During the three months ended March 31, 2022 and through the date of this Quarterly Report on Form 10-Q, the Company sold 404,600 shares of common stock under this program with net proceeds (after deducting commissions and other offering expenses) of $0.8 million. Equity Plans The Company maintains one stock incentive plan, the 2014 Incentive Plan, or the 2014 Plan, as well as the 2014 Employee Stock Purchase Plan, or the 2014 ESPP. The 2014 Plan replaced the Company’s Amended and Restated 2008 Equity Incentive Plan, or the 2008 Plan, however, options or other awards granted under the 2008 Plan prior to the adoption of the 2014 Plan that have not been settled or forfeited remain outstanding and effective. On June 6, 2019, the Company’s stockholders approved the Amended and Restated 2014 Employee Stock Purchase Plan, or the ESPP. The Company also maintains an inducement award program that is separate from the Company's equity plans under which inducement awards may be granted consistent with Nasdaq Listing Rule 5635(c)(4). During the three months ended March 31, 2022, the Company granted 279,000 options to purchase shares of the Company’s common stock to new hires as inducements material to such employees' entering into employment with the Company, of which 279,000 options remained outstanding as of March 31, 2022. The 2014 Plan allows for the granting of stock options, stock appreciation rights, or SARs, restricted stock, unrestricted stock, RSUs, performance awards and other awards convertible into or otherwise based on shares of the Company’s common stock. Dividend equivalents may also be provided in connection with an award under the 2014 Plan. The Company’s employees, officers, directors and consultants and advisors are eligible to receive awards under the 2014 Plan. The Company initially reserved 1,785,000 shares of its common stock for the issuance of awards under the 2014 Plan. The 2014 Plan provides that the number of shares reserved and available for issuance under the 2014 Plan will automatically increase annually on January 1 of each calendar year, by an amount equal to three percent (3%) of the number of the Company's outstanding shares on a fully diluted basis as of the close of business on the immediately preceding December 31, or the 2014 Plan Evergreen Provision. The Company’s Board of Directors may act prior to January 1 of any year to provide that there will be no automatic increase in the number of Akebia Shares available for grant under the 2014 Plan for that year (or that the increase will be less than the amount that would otherwise have automatically been made). On December 12, 2018, in connection with the consummation of the Merger, the Company assumed outstanding and unexercised options to purchase Keryx's stock, as adjusted by the Exchange Multiplier pursuant to the terms of the Merger Agreement, under the following Keryx equity plans, or the Keryx Equity Plans: the Keryx 1999 Share Option Plan, the Keryx 2004 Long-Term Incentive Plan, the Keryx 2007 Incentive Plan, the Keryx Amended and Restated 2013 Incentive Plan, and the Keryx 2018 Equity Incentive Plan, or the Keryx 2018 Plan. In addition, the number of Keryx Shares available for issuance under the Keryx 2018 Plan, as adjusted by the Exchange Multiplier pursuant to the terms of the Merger Agreement, may be used for awards granted by the Company under its 2014 Plan, or the Assumed Shares, provided that the Company uses the Assumed Shares for individuals who were not employees or directors of the Company prior to the consummation of the Merger. The Company grants annual service-based stock options to employees under the 2014 Plan. During the three months ended March 31, 2022, the Company issued 2,833,500 options to employees. In addition, the Company issues stock options to directors, new hires and occasionally to other employees not in connection with the annual grant process. Options granted by the Company generally vest over periods of between 12 and 48 months, subject, in each case, to the individual’s continued service through the applicable vesting date. Options generally vest either 100% on the first anniversary of the grant date or in installments of (i) 25% at the one year anniversary and (ii) 12 equal quarterly installments beginning after the one year anniversary of the grant date, subject to the individual’s continuous service with the Company. Options generally expire 10 years after the date of grant. The Company also grants performance-based stock options to employees under the 2014 Plan. The Company issued no performance-based stock options during the three months ended March 31, 2022. The performance-based stock options granted by the Company generally vest in connection with the achievement of specified commercial and regulatory milestones. The performance-based stock options also generally feature a time-based vesting component. The expense recognized for these awards is based on the grant date fair value of the Company’s common stock multiplied by the number of options granted and recognized over time based on the probability of meeting such commercial and regulatory milestones. The Company also grants annual service-based restricted stock units, or RSUs, to employees under the 2014 Plan. During the three months ended March 31, 2022, the Company issued 2,914,308 RSUs to employees. The Company also occasionally issues RSUs not in connection with the annual grant process to employees. Generally, RSUs granted by the Company vest in one of the following ways: (i) 100% of each RSU grant vests on the first or third anniversary of the grant date, (ii) one third of each RSU grant vests on the first, second and third anniversaries of the grant date, or (iii) 50% of each RSU grant vests on the first anniversary and 25% of each RSU grant vests every six months after the one year anniversary of the grant date, subject, in each case, to the individual’s continued service through the applicable vesting date. The expense recognized for these awards is based on the grant date fair value of the Company’s common stock multiplied by the number of units granted and recognized on a straight-line basis over the vesting period. The Company also grants performance-based restricted stock units, or PSUs, to employees under the 2014 Plan. The Company issued no PSUs during the three months ended March 31, 2022. The PSUs granted by the Company generally vest in connection with the achievement of specified commercial and regulatory milestones. The PSUs also generally feature a time-based vesting component. The expense recognized for these awards is based on the grant date fair value of the Company’s common stock multiplied by the number of units granted and recognized over time based on the probability of meeting such commercial and regulatory milestones. The ESPP provides for the issuance of options to purchase shares of the Company’s common stock to participating employees at a discount to their fair market value. As noted above, the Company’s stockholders approved the ESPP, which amended and restated the Company’s 2014 ESPP, on June 6, 2019. As of March 31, 2022, the maximum aggregate number of shares of the Company’s common stock available for future issuance under the ESPP is 4,981,995. Under the ESPP, each offering period is six months, at the end of which employees who elect to purchase shares of the Company’s common stock through payroll deductions made over the term of the offering. The per-share purchase price at the end of each offering period is equal to the lesser of eighty-five percent (85%) of the closing price of the Company’s common stock at the beginning or end of the offering period. The Company issued 191,146 shares under the ESPP during the three months ended March 31, 2022.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

Commitments and Contingencies

3 Months Ended

Mar. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Leases

The Company leases approximately 65,167 square feet of office and lab space in Cambridge, Massachusetts under a lease which was most recently amended in November 2020, collectively the Cambridge Lease. Under the Third Amendment to the Cambridge Lease, or the Third Amendment, executed in July 2016, total monthly lease payments under the initial base rent were approximately $242,000 and are subject to annual rent escalations. In addition to such annual rent escalations, base rent payments for a portion of said premises commenced on January 1, 2017 in the monthly amount of approximately $22,000. The Fourth Amendment to the Cambridge Lease, executed in May 2017, provided additional storage space to the Company and did not impact rent payments. In April 2018, the Company entered into a Fifth Amendment to the Cambridge Lease, or the Fifth Amendment, for an additional 19,805 square feet of office space on the 12th floor. Monthly lease payments for the existing 45,362 square feet of office and lab space, under the Third Amendment, remain unchanged. The new space leased by the Company was delivered in September 2018 and additional monthly lease payments of approximately $135,000 commenced in February 2019 and are subject to annual rent escalations, which commenced in September 2019. In November 2020, the Company entered into a Sixth Amendment to the Cambridge Lease, or the Sixth Amendment, to extend the term of the Cambridge Lease with respect to the lab space from November 30, 2021 to January 31, 2025. The Sixth Amendment includes two months of free rent starting in December 2020 and additional monthly lease payments of approximately $48,000, which commenced in December 2021, and is subject to annual rent escalations, which commence in December 2022.

Additionally, as a result of the Merger, the Company has a lease for 27,300 square feet of office space in Boston, Massachusetts, or the Boston Lease. The total monthly lease payments under the initial base rent were approximately $136,000 and are subject to annual rent escalations. In February 2022, the Company entered into the First Amendment to the Boston Lease, or the First Lease Amendment, to extend the term of the Boston Lease from February 2023 to July 2031. The First Lease Amendment includes five months of free rent starting in March 2023 and monthly lease payments of $200,122 commencing on August 1, 2023, with an annual rent escalation of approximately 2% commencing on August 1, 2024. The First Lease Amendment also includes a landlord's allowance for certain leasehold improvements to the premises in an amount of up to $1,954,680, provided that such allowance must be used prior to August 1, 2024.

The term of the Cambridge Lease with respect to the office space expires on September 11, 2026, with one five-year extension option available. The term of the Boston Lease office space expires on July 31, 2031, with an extension option for one additional five-year term available. The renewal options in these real estate leases were not included in the calculation of the operating lease assets and operating lease liabilities as the renewal is not reasonably certain. The term of the Cambridge Lease with respect to the lab space expires on January 31, 2025, with an extension option for one additional period through September 11, 2026. The renewal option in this real estate lease was included in the calculation of the operating lease assets and operating lease liabilities as the renewal is reasonably certain. The lease agreements do not contain residual value guarantees. Operating lease costs were $1.8 million and $1.7 million for the three months ended March 31, 2022 and 2021, respectively. Cash paid for amounts included in the measurement of operating lease liabilities was $1.8 million for each of the three months ended March 31, 2022 and 2021.

In September 2019, Keryx entered into an agreement to sublease the Boston office space to Foundation Medicine, Inc., or Foundation. The sublease is subject and subordinate to the Boston Lease between Keryx and the landlord. The term of the sublease commenced on October 16, 2019, upon receipt of the required consent from the landlord for the sublease agreement, and expires on February 27, 2023. Foundation is obligated to pay Keryx rent that approximates the rent due from Keryx to its

landlord with respect to the Boston Lease. Sublease rental income is recorded to other income. Keryx continues to be obligated for all payment terms pursuant to the Boston Lease, and the Company will guaranty Keryx’s obligations under the sublease. Keryx recorded $0.5 million and $0.4 million in sublease rental income from Foundation during the three months ended March 31, 2022 and 2021, respectively.

The Company has not entered into any material short-term leases or financing leases as of March 31, 2022.

The total security deposit in connection with the Cambridge Lease is $1.6 million as of March 31, 2022. Additionally, the Company recorded $1.4 million for the security deposit under the Boston Lease. Both the Cambridge Lease and the Boston Lease have their security deposits in the form of a letter of credit, all of which are included as restricted cash in other assets in the Company’s unaudited condensed consolidated balance sheets as of March 31, 2022.

As of March 31, 2022, undiscounted minimum rental commitments under non-cancelable leases, for each of the next five years and total thereafter are as follows:


	Operating Leases		Lease Payments to be Received from Sublease		Net Operating Lease Payments
	(in thousands)
Remaining 2022	$	5,502	$	1,370	$	4,132
2023	6,954		307		6,647
2024	8,167		—		8,167
2025	8,293		—		8,293
2026	6,571		—		6,571
Thereafter	12,200		—		12,200
Total	$	47,687	$	1,677	$	46,010

In arriving at the operating lease liabilities, the Company applied incremental borrowing rates ranging from 6.65% to 7.25%, which were based on the remaining lease term at either the date of adoption of ASC 842 or the effective date of any subsequent lease term extensions. As of March 31, 2022, the remaining lease terms ranged from 4.45 years to 9.34 years. As of March 31, 2022, the following represents the difference between the remaining undiscounted minimum rental commitments under non-cancelable leases and the operating lease liabilities:


	Operating Leases
	(in thousands)
Undiscounted minimum rental commitments	$	47,687
Present value adjustment using incremental borrowing rate	(10,006)
Operating lease liabilities	$	37,681

Manufacturing Agreements

As a result of the Merger, the Company's contractual obligations include Keryx’s commercial supply agreements with BioVectra Inc., or BioVectra, and Siegfried Evionnaz SA, or Siegfried, to supply commercial drug substance for Auryxia.

Pursuant to the Manufacture and Supply Agreement with BioVectra and the Product Manufacture and Supply and Facility Construction Agreement with BioVectra, the Company agreed to purchase minimum quantities of Auryxia drug substance annually at predetermined prices. On September 4, 2020, the Company and BioVectra entered into an Amended and Restated Product Manufacture and Supply and Facility Construction Agreement, which provided for reduced minimum quantity commitments and revised the predetermined prices. The price per kilogram decreases with an increase in quantity above the predetermined purchase quantity tiers. In addition, the Manufacture and Supply Agreement with BioVectra and the Amended and Restated Product Manufacture and Supply and Facility Construction Agreement with BioVectra, require the Company to reimburse BioVectra for certain costs in connection with construction of a new facility for the manufacture and supply of Auryxia drug substance. These construction costs are recorded in other assets and amortized into drug substance as inventory is released to the Company from BioVectra. The term of the Manufacture and Supply Agreement with BioVectra expires on December 31, 2022. The term of the Amended and Restated Product Manufacture and Supply and Facility Construction Agreement expires on December 31, 2026, after which it automatically renews for successive one-year terms unless either party

gives notice of its intention to terminate within a specified time prior to the end of the then-current term. In addition, the Company and BioVectra each have the ability to terminate these agreements upon the occurrence of certain conditions. As of March 31, 2022, the Company is required to reimburse BioVectra for certain costs in connection with the construction of the new facility and to purchase minimum quantities of Auryxia drug substance annually for a total cost of approximately $83.6 million through the end of the contract term.

Pursuant to the Siegfried Master Manufacturing Services and Supply Agreement, as amended (the most recent amendment having been executed on February 11, 2021), or the Siegfried Agreement, the Company has agreed to purchase a minimum quantity of drug substance of Auryxia at predetermined prices. The price per kilogram will decrease with an increase in quantity above the minimum purchase quantity. The term of the Siegfried Agreement expires on December 31, 2022, subject to the Company's option to extend the term through December 31, 2023 by providing 12 months’ prior written notice to Siegfried. The Siegfried Agreement provides the Company and Siegfried with certain early termination rights. In the first quarter of 2022, the Company notified Siegfried that the Company has elected not to exercise the option to extend the term of the Siegfried Agreement through December 31, 2023. As of March 31, 2022, the Company is required to purchase a minimum quantity of drug substance for Auryxia annually at a total cost of approximately $13.5 million through the year ending December 31, 2022.

As part of purchase accounting, the Company identified executory contracts in the commercial supply agreements between Keryx and its contract manufacturers for Auryxia, which include future firm purchase commitments. These executory contracts were deemed to have an off-market element related to the amount of purchase commitments that exceed the current forecast. The Company regularly reviews its estimate of the excess purchase commitment liability including a review of assumptions of expected future demand, estimates of anticipated expiry of inventory under firm purchase commitments that are estimated to expire before they could be sold as well as any modifications to supply agreements during each reporting period. The excess purchase commitment liability relating to these executory contracts was $72.7 million and $76.7 million as of March 31, 2022 and December 31, 2021, respectively. During the quarter ended March 31, 2022, the Company reviewed the detailed assumptions above and recorded a $0.8 million reduction to the excess purchase commitments liability within cost of goods sold. During the quarter ended March 31, 2022, the Company reduced the excess purchase commitment liability by $3.2 million for inventory received that had previously been identified as excess.

On April 9, 2019, the Company entered into a Supply Agreement with Esteve Química, S.A., or Esteve, or the Esteve Agreement. The Esteve Agreement includes the terms and conditions under which Esteve will manufacture vadadustat drug substance for commercial use. Pursuant to the Esteve Agreement, the Company provides rolling forecasts to Esteve on a quarterly basis, or the Esteve Forecast. The Esteve Forecast reflects the Company’s needs for vadadustat drug substance produced by Esteve over a certain number of months, represented as a quantity of vadadustat drug substance per calendar quarter. The parties have agreed to a volume-based pricing structure under the Esteve Agreement. The Esteve Agreement has an initial term of four years, beginning April 9, 2019 and ending April 9, 2023. Pursuant to the Esteve Agreement, the Company has agreed to purchase a certain percentage of the global demand for vadadustat drug substance from Esteve. As of March 31, 2022, the Company has committed to purchase $39.0 million of vadadustat drug substance from Esteve through the second quarter of 2023.

On March 11, 2020, the Company entered into a Supply Agreement with Patheon Inc., or Patheon, or the Patheon Agreement. The Patheon Agreement includes the terms and conditions under which Patheon will manufacture vadadustat drug product for commercial use. Pursuant to the Patheon Agreement, the Company provides Patheon a long-term forecast on an annual basis, as well as short-term forecasts on a quarterly basis, or the Patheon Forecast. The Patheon Forecast reflects the Company’s needs for commercial supply of vadadustat drug product produced by Patheon, represented as a quantity of drug product per calendar quarter. The parties have agreed to a volume-based pricing structure under the Patheon Agreement. The Patheon Agreement has an initial term beginning March 11, 2020 and ending June 30, 2023. Pursuant to the Patheon Agreement, the Company has agreed to purchase a certain percentage of the global demand for vadadustat drug product from Patheon. As of March 31, 2022, the Company had a minimum commitment with Patheon for $3.9 million through the fourth quarter of 2022.

On April 2, 2020, the Company entered into a Supply Agreement with STA Pharmaceutical Hong Kong Limited, a subsidiary of WuXi AppTec, or WuXi STA, as amended on April 15, 2021, or the WuXi STA DS Agreement. The WuXi STA DS Agreement includes the terms and conditions under which WuXi STA will manufacture vadadustat drug substance for commercial use. Pursuant to the WuXi STA DS Agreement, the Company provides rolling forecasts to WuXi STA on a quarterly basis, or the WuXi STA DS Forecast. The WuXi STA DS Forecast reflects the Company’s needs for vadadustat drug substance produced by WuXi STA over a certain number of quarters. The parties have agreed to a volume-based pricing structure under the WuXi STA DS Agreement. The WuXi STA DS Agreement has an initial term of four years, beginning April 2, 2020 and ending April 2, 2024. Pursuant to the WuXi STA DS Agreement, the Company has agreed to purchase a certain percentage of the global demand for vadadustat drug substance from WuXi STA. As of March 31, 2022, the Company has committed to purchase $77.9 million of vadadustat drug substance from WuXi STA through the end of 2023.

On February 10, 2021, the Company entered into a Supply Agreement with WuXi STA, or the WuXi STA DP Agreement. The WuXi STA DP Agreement includes the terms and conditions under which WuXi STA will manufacture and supply vadadustat

drug product for commercial purposes. Pursuant to the WuXi STA DP Agreement, the Company will provide rolling forecasts to WuXi STA on a quarterly basis, or the WuXi STA DP Forecast. Each WuXi STA DP Forecast will reflect the quantities of vadadustat drug product that the Company expects to order from WuXi STA over a certain number of months, represented as a quantity of vadadustat drug product per calendar quarter. Pursuant to the WuXi STA DP Agreement, the Company has agreed to purchase a certain percentage of global demand for vadadustat drug product from WuXi STA. The parties have agreed to a volume-based pricing structure under the WuXi STA DP Agreement. The vadadustat drug product price will remain fixed for the first 12 months and thereafter shall be annually reviewed by the Company and WuXi STA. The Company will also reimburse WuXi STA for certain reasonable expenses. The WuXi STA DP Agreement has an initial term of four years, beginning February 10, 2021 and ending February 10, 2025. The WuXi STA DP Agreement may be renewed or extended by mutual agreement of the Company and WuXi STA with at least 18 months’ prior written notice. The WuXi STA DP Agreement allows the Company to terminate the agreement on 180 calendar days’ prior written notice to WuXi STA for any reason. In addition, each party has the ability to terminate the WuXi STA DP Agreement upon the occurrence of certain conditions.

Other Third-Party Contracts

Under the Company’s agreement with IQVIA to provide contract research organization services for the PRO2TECT and INNO2VATE programs, the total remaining contract costs as of March 31, 2022 were approximately $4.7 million, of which Otsuka reimburses a significant portion back to the Company. Substantive performance for the committed work with IQVIA was completed in 2020 and close out activities will be performed throughout 2022. The Company also contracts with various other organizations to conduct research and development activities with remaining contract costs to the Company of approximately $211.9 million at March 31, 2022. The scope of the services under these research and development contracts can be modified and the contracts cancelled by the Company upon written notice. In some instances, the contracts may be cancelled by the third party upon written notice.

Litigation and Related Matters

From time to time, the Company may become subject to legal proceedings and claims which arise in the ordinary course of its business. Consistent with ASC 450, Contingencies, the Company’s policy is to record a liability if a loss in a significant legal dispute is considered probable and an amount can be reasonably estimated. The Company provides disclosure when a loss in excess of any reserve is reasonably possible, and if estimable, the Company discloses the potential loss or range of possible loss. Significant judgment is required to assess the likelihood of various potential outcomes and the quantification of loss in those scenarios. The Company’s estimates change as litigation progresses and new information comes to light. Changes in Company estimates could have a material impact on the Company’s results and financial position. As of March 31, 2022, the Company does not have any significant legal disputes that require a loss liability to be recorded. The Company continually monitors the need for a loss liability for litigation and related matters.

Net Loss per Share

3 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Net Loss per Share

For purposes of the diluted net loss per share calculation, preferred stock, stock options, warrants, restricted stock and RSUs are considered to be common stock equivalents and have been excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive for periods presented. Therefore, basic and diluted net loss per share were the same for all periods presented in the unaudited condensed consolidated statement of operations and comprehensive loss. The shares in the table below were excluded from the calculation of diluted net loss per share, prior to the use of the treasury stock method, due to their anti-dilutive effect:


	As of March 31,
	2022	2021
Warrant	—	509,611
Outstanding stock options	14,187,899	11,369,546
Unvested restricted stock units	5,782,635	6,523,240
Total	19,970,534	18,402,397

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Reduction in Force On April 4, 2022, the Board of Directors of the Company approved a reduction of the Company’s workforce by approximately 42% across all areas of the Company (47% inclusive of the closing of the majority of open positions) following the receipt of a CRL from the FDA to the Company’s NDA for vadadustat for the treatment of anemia due to CKD in adult patients. This workforce reduction will be substantially completed by the end of the second quarter of 2022. On May 5, 2022, the Company implemented a further reduction in workforce consisting of several members of management. This workforce reduction is expected to be substantially complete by the end of January 2023. These actions reflect the Company’s determination to refocus its strategic priorities around its commercial product, Auryxia®, and its development portfolio, and are steps in a cost savings plan to significantly reduce the Company’s expense profile in line with being a single commercial product company. The Company plans to seek to effect additional measures to further reduce its operating expenses and increase revenue from Auryxia. Affected employees in the workforce reductions were offered separation benefits, including severance payments, healthcare coverage and related benefits. The Company expects to record restructuring charges of approximately $16.5 million in the aggregate primarily related to one-time termination benefits and contractual termination benefits including severance, non-cash stock-based compensation expense, healthcare and related benefits primarily in the second quarter of 2022. The Company may incur additional costs not currently contemplated due to events associated with or resulting from the workforce reduction. The charge that the Company expects to incur in connection with the workforce reductions is an estimate and is subject to a number of assumptions, and actual results may differ materially. At-the-Market Facility Agreement On April 7, 2022, the Company entered into an Open Market Sale AgreementSM, or the sales agreement, with Jefferies LLC, or Jefferies, as agent, for the offer and sale of common stock at current market prices in amounts to be determined from time to time. Also, on April 7, 2022, the Company filed a prospectus supplement relating to the sales agreement, pursuant to which it is able to offer and sell under the sales agreement up to $26.0 million of its common stock at current market prices from time to time. From the date of filing of the prospectus supplement through the date of the filing of this Quarterly Report on Form 10-Q, the Company has not sold any shares of its common stock under this program.

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S., or GAAP, for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.
Consolidation	In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the unaudited condensed consolidated financial statements have been included. Interim results for the three months ended March 31, 2022 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2022 or any other future period.The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
New Accounting Pronouncements - Not Yet Adopted	New Accounting Pronouncements – Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments provide optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The Company is currently evaluating its contracts and the optional expedients provided by the new standard.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with 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 the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: prepaid and accrued research and development expense, operating lease assets and liabilities, derivative liabilities, refund liabilities to customers, other non-current liabilities, including the excess purchase commitment liability, stock-based compensation expense, product and collaboration revenues including various rebates and reserves related to product sales, non-cash interest expense on the liability related to sale of future royalties, inventories, income taxes, intangible assets and goodwill. Although the Company regularly assesses these estimates, actual results could differ materially from these estimates. Changes in estimates are recorded in the period they become known. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances.

Product Revenue and Reserves for Variable Consideration (Tables)

3 Months Ended

Mar. 31, 2022

Revenue from Contract with Customer [Abstract]

Product Revenue Allowance and Reserve Categories

The following table summarizes activity in each of the product revenue allowance and reserve categories for the three months ended March 31, 2022 and 2021 (in thousands):


	Chargebacks and Discounts		Rebates, Fees and other Deductions		Returns		Total
Balance at December 31, 2021	$	1,278	$	26,625	$	475	$	28,378
Current provisions related to sales in current year	2,711		21,324		1,359		25,394
Adjustments related to prior year sales	(132)		779		—		647
Credits/payments made	(2,465)		(22,491)		(1,293)		(26,249)
Balance at March 31, 2022	$	1,392	$	26,237	$	541	$	28,170

Balance at December 31, 2020	$	802	$	39,912	$	649	$	41,363
Current provisions related to sales in current year	3,170		33,643		2,152		38,965
Adjustments related to prior year sales	3		(1,241)		—		(1,238)
Credits/payments made	(2,646)		(29,098)		(1,917)		(33,661)
Balance at March 31, 2021	$	1,329	$	43,216	$	884	$	45,429

License, Collaboration and Other Significant Agreements (Tables)

3 Months Ended

Mar. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Revenues Recognized from License, Collaboration and Other Significant Agreements


	Three Months Ended March 31,
	2022		2021
License, Collaboration and Other Revenue:	(in thousands)
MTPC Agreement	$	7,962	$	18
Otsuka U.S. Agreement	5,638		13,674
Otsuka International Agreement	5,503		6,972
Total Proportional Performance Revenue	$	19,103	$	20,664
JT and Torii	1,148		1,159
MTPC Other Revenue	—		73
Total License, Collaboration and Other Revenue	$	20,251	$	21,896

Deferred Revenues


	Three Months Ended March 31, 2022
	Short-Term		Long-Term		Total
Deferred Revenue:	(in thousands)
MTPC Agreement	$	—	$	—	$	—
Otsuka U.S. Agreement	6,192		16,087		22,279
Otsuka International Agreement	4,248		5,973		10,221
Vifor Pharma Agreement	—		43,296		43,296
Total	$	10,440	$	65,356	$	75,796

Changes in Contract Assets and Liabilities

The following table presents changes in the Company’s contract assets and liabilities during the three months ended March 31, 2022 and 2021 (in thousands):


Three Months Ended March 31, 2022	Balance at Beginning of Period		Additions		Deductions		Balance at End of Period
Contract assets:
Accounts receivable(1)	$	19,094	$	19,542	$	(14,320)	$	24,316
Prepaid expenses and other current assets	$	4,309	$	—	$	(339)	$	3,970
Contract liabilities:
Deferred revenue	$	42,380	$	60,514	$	(27,098)	$	75,796
Accounts payable	$	3,171	$	—	$	(2,852)	$	319
Accrued expenses and other current liabilities	$	—	$	—	$	—	$	—

Three Months Ended March 31, 2021
Contract assets:
Accounts receivable(1)	$	3,045	$	6,740	$	(6,246)	$	3,539
Prepaid expenses and other current assets	$	1,722	$	194	$	—	$	1,916
Contract liabilities:
Deferred revenue	$	40,559	$	22,895	$	(25,902)	$	37,552
Accounts payable	$	7,227	$	—	$	(7,227)	$	—
Accrued expenses and other current liabilities	$	10,000	$	—	$	—	$	10,000

Revenue Recognized Resulting from Changes in Contract Assets and Contract Liabilities


	Three Months Ended March 31,
Revenue Recognized in the Period from:	2022		2021
Amounts included in deferred revenue at the beginning of the period	$	6,602	$	5,382
Performance obligations satisfied in previous periods	$	—	$	—

Liability Related to Sale of Future Royalties (Tables)

3 Months Ended

Mar. 31, 2022

Other Liabilities Disclosure [Abstract]

Activity within Liability Related to Sale of Future Royalties, net

The following table shows the activity within the liability account for the three months ended March 31, 2022:


	March 31, 2022
	(in thousands)
Liability related to sale of future royalties, net beginning balance at December 31, 2021	$	53,079
MTPC royalties payable	(329)
Non-cash interest expense recognized	2,345
Liability related to sale of future royalties, net — ending balance	$	55,095

Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Assets Measured or Disclosed at Fair Value on Recurring Basis

Assets measured or disclosed at fair value on a recurring basis as of March 31, 2022 and December 31, 2021 are summarized below:


	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(in thousands)
March 31, 2022
Assets:
Cash and cash equivalents	$	174,562	$	—	$	—	$	174,562
	$	174,562	$	—	$	—	$	174,562
Liabilities:
Derivative liability	$	—	$	—	$	1,110	$	1,110
	$	—	$	—	$	1,110	$	1,110


	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(in thousands)
December 31, 2021
Assets:
Cash and cash equivalents	$	149,800	$	—	$	—	$	149,800
	$	149,800	$	—	$	—	$	149,800
Liabilities:
Derivative liability	$	—	$	—	$	1,820	$	1,820
	$	—	$	—	$	1,820	$	1,820

Fair Value Derivative Liability

The following table provides a roll-forward of the fair value of the derivative liability (in thousands):


Balance at December 31, 2021	$	1,820
Change in fair value of derivative liability, recorded as other expense	(710)
Balance at March 31, 2022	$	1,110

Inventory (Tables)

3 Months Ended

Mar. 31, 2022

Inventory Disclosure [Abstract]

Inventory Components

The components of inventory are summarized as follows:


	March 31, 2022		December 31, 2021
	(in thousands)
Raw materials	$	678	$	1,763
Work in process	74,025		62,635
Finished goods	8,207		14,661
Total inventory	$	82,910	$	79,059

Long-term inventory, which primarily consists of raw materials and work in process, is included in other assets in the Company’s unaudited condensed consolidated balance sheets.


	March 31, 2022		December 31, 2021
	(in thousands)
Balance Sheet Classification:
Inventory	$	39,422	$	38,195
Other assets	43,488		40,864
Total inventory	$	82,910	$	79,059

Intangible Assets and Goodwill (Tables)

3 Months Ended

Mar. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

The following table presents the Company’s intangible assets at March 31, 2022 and December 31, 2021 (in thousands):


	March 31, 2022
	Gross Carrying Value		Accumulated Amortization		Total
Intangible assets:
Developed product rights for Auryxia	$	213,603	$	(114,487)	$	99,116
Total	$	213,603	$	(114,487)	$	99,116


	December 31, 2021
	Gross Carrying Value		Accumulated Amortization		Total
Intangible assets:
Developed product rights for Auryxia	$	213,603	$	(105,476)	$	108,127
Total	$	213,603	$	(105,476)	$	108,127

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2022

Payables and Accruals [Abstract]

Accrued Expenses

Accrued expenses as of March 31, 2022 and December 31, 2021 are as follows:


	March 31, 2022		December 31, 2021
	(in thousands)
Product revenue allowances	$	26,236	$	26,624
Accrued clinical	16,710		14,036
Amounts due to collaboration partners	28,019		22,654
Accrued payroll and related	7,130		15,863
Lease liability	4,763		4,802
Royalties	3,175		3,472
Professional fees	2,711		1,899
Accrued commercial manufacturing	3,884		3,843
Accrued other	17,032		11,263
Total accrued expenses	$	109,660	$	104,456

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Undiscounted Minimum Rental Commitments Under Non-Cancelable Leases

As of March 31, 2022, undiscounted minimum rental commitments under non-cancelable leases, for each of the next five years and total thereafter are as follows:


	Operating Leases		Lease Payments to be Received from Sublease		Net Operating Lease Payments
	(in thousands)
Remaining 2022	$	5,502	$	1,370	$	4,132
2023	6,954		307		6,647
2024	8,167		—		8,167
2025	8,293		—		8,293
2026	6,571		—		6,571
Thereafter	12,200		—		12,200
Total	$	47,687	$	1,677	$	46,010

Difference Between Undiscounted Minimum Rental Commitments Under Non-Cancelable Leases and Operating Leases Liabilities

As of March 31, 2022, the following represents the difference between the remaining undiscounted minimum rental commitments under non-cancelable leases and the operating lease liabilities:


	Operating Leases
	(in thousands)
Undiscounted minimum rental commitments	$	47,687
Present value adjustment using incremental borrowing rate	(10,006)
Operating lease liabilities	$	37,681

Net Loss per Share (Tables)

3 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Anti-Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share

The shares in the table below were excluded from the calculation of diluted net loss per share, prior to the use of the treasury stock method, due to their anti-dilutive effect:


	As of March 31,
	2022	2021
Warrant	—	509,611
Outstanding stock options	14,187,899	11,369,546
Unvested restricted stock units	5,782,635	6,523,240
Total	19,970,534	18,402,397

Nature of Organization and Operations - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 174,562	$ 149,800

Summary of Significant Accounting Policies (Details)	3 Months Ended
Summary of Significant Accounting Policies (Details)	Mar. 31, 2022 segment
Accounting Policies [Abstract]
Number of operating segments	1

Product Revenue and Reserves for Variable Consideration - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenues	$ 61,699	$ 52,304
Product revenue, net
Disaggregation of Revenue [Line Items]
Total revenues	41,448	$ 30,408
Accounts receivable, net	$ 27,700		$ 24,600

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Product Revenue and Reserves for Variable Consideration - Product Revenue Allowance and Reserve Categories (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 28,378	$ 41,363
Current provisions related to sales in current year	25,394	38,965
Adjustments related to prior year sales	647	(1,238)
Credits/payments made	(26,249)	(33,661)
Ending balance	28,170	45,429
Chargebacks and Discounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	1,278	802
Current provisions related to sales in current year	2,711	3,170
Adjustments related to prior year sales	(132)	3
Credits/payments made	(2,465)	(2,646)
Ending balance	1,392	1,329
Rebates, Fees and other Deductions
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	26,625	39,912
Current provisions related to sales in current year	21,324	33,643
Adjustments related to prior year sales	779	(1,241)
Credits/payments made	(22,491)	(29,098)
Ending balance	26,237	43,216
Returns
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	475	649
Current provisions related to sales in current year	1,359	2,152
Adjustments related to prior year sales	0	0
Credits/payments made	(1,293)	(1,917)
Ending balance	$ 541	$ 884

License, Collaboration and Other Significant Agreements - Revenues Recognized From License, Collaboration and Other Significant Agreements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
License, Collaboration and Other Revenue:
Total revenues	$ 61,699	$ 52,304
Mitsubishi Tanabe Pharma Corporation
License, Collaboration and Other Revenue:
Total revenues	1,600
License, collaboration and other revenue
License, Collaboration and Other Revenue:
Total revenues	20,251	21,896
License, collaboration and other revenue \| Mitsubishi Tanabe Pharma Corporation
License, Collaboration and Other Revenue:
Total revenues	7,962	18
License, collaboration and other revenue \| Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement
License, Collaboration and Other Revenue:
Total revenues	5,638	13,674
License, collaboration and other revenue \| Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement
License, Collaboration and Other Revenue:
Total revenues	5,503	6,972
License, collaboration and other revenue \| Total Proportional Performance Revenue
License, Collaboration and Other Revenue:
Total revenues	19,103	20,664
License, collaboration and other revenue \| JT and Torii
License, Collaboration and Other Revenue:
Total revenues	1,148	1,159
License, collaboration and other revenue \| MTPC Other Revenue \| Mitsubishi Tanabe Pharma Corporation
License, Collaboration and Other Revenue:
Total revenues	$ 0	$ 73

License, Collaboration and Other Significant Agreements - Deferred Revenue (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Deferred Revenue:
Short-Term	$ 10,440	$ 20,906
Long-Term	65,356	$ 21,474
Total	75,796
Mitsubishi Tanabe Pharma Corporation \| MTPC Agreement
Deferred Revenue:
Short-Term	0
Long-Term	0
Total	0
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement
Deferred Revenue:
Short-Term	6,192
Long-Term	16,087
Total	22,279
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement
Deferred Revenue:
Short-Term	4,248
Long-Term	5,973
Total	10,221
Vifor Pharma
Deferred Revenue:
Short-Term	0
Long-Term	43,296
Total	$ 43,296

License, Collaboration and Other Significant Agreements - Changes in Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Contract liabilities:
Balance at End of Period	$ 75,796
Accounts receivable
Contract assets:
Balance at Beginning of Period	19,094	$ 3,045
Additions	19,542	6,740
Deductions	(14,320)	(6,246)
Balance at End of Period	24,316	3,539
Prepaid expenses and other current assets
Contract assets:
Balance at Beginning of Period	4,309	1,722
Additions	0	194
Deductions	(339)	0
Balance at End of Period	3,970	1,916
Deferred revenue
Contract liabilities:
Balance at Beginning of Period	42,380	40,559
Additions	60,514	22,895
Deductions	(27,098)	(25,902)
Balance at End of Period	75,796	37,552
Accounts payable
Contract liabilities:
Balance at Beginning of Period	3,171	7,227
Additions	0	0
Deductions	(2,852)	(7,227)
Balance at End of Period	319	0
Accrued expenses and other current liabilities
Contract liabilities:
Balance at Beginning of Period	0	10,000
Additions	0	0
Deductions	0	0
Balance at End of Period	$ 0	$ 10,000

License, Collaboration and Other Significant Agreements - Revenue Recognized Resulting from Changes in Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue Recognized in the Period from:
Amounts included in deferred revenue at the beginning of the period	$ 6,602	$ 5,382
Performance obligations satisfied in previous periods	$ 0	$ 0

License, Collaboration and Other Significant Agreements - Mitsubishi Tanabe Pharma Corporation Collaboration Agreement (Details)	3 Months Ended
	Mar. 31, 2022 USD ($) performance_obligation	Mar. 31, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue	$ 61,699,000	$ 52,304,000
Deferred revenue	75,796,000
Revenue recognized	6,602,000	5,382,000
Deferred revenue, net of current portion	65,356,000			$ 21,474,000
Short-term deferred revenue	10,440,000			20,906,000
Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable	24,316,000	3,539,000		$ 19,094,000	$ 3,045,000
Mitsubishi Tanabe Pharma Corporation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue	1,600,000
Mitsubishi Tanabe Pharma Corporation \| License Collaboration And Other Revenue, Royalties
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue	300,000	0
Mitsubishi Tanabe Pharma Corporation \| Regulatory Milestone Payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue	$ 25,000,000
Mitsubishi Tanabe Pharma Corporation \| MTPC Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of performance obligations \| performance_obligation	2
Deferred revenue	$ 0
Deferred revenue, net of current portion	0
Short-term deferred revenue	0
Mitsubishi Tanabe Pharma Corporation \| MTPC Agreement \| Regulatory Milestone Payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue	15,000,000
Mitsubishi Tanabe Pharma Corporation \| Development And Commercialize Research And License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received	20,000,000
Cost of research services	20,500,000
Milestone revenue	10,000,000
Deferred revenue	0
Accounts receivable	0
Mitsubishi Tanabe Pharma Corporation \| Development And Commercialize Research And License Agreement \| Regulatory Milestone Payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue	10,000,000
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received			$ 10,400,000
Accounts receivable	0
Revenue recognized	0	0
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited \| Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable	200,000
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited \| Other Current Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Short-term deferred revenue	1,900,000
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation And Otsuka Pharmaceutical Company Limited \| Other Noncurrent Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, net of current portion	0
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation Supply Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	7,600,000	$ 0
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation Supply Agreement \| Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up-front payments invoiced	12,900,000
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation Supply Agreement \| Other Current Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up-front payments invoiced	18,300,000
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation Supply Agreement \| Other Noncurrent Liabilities
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up-front payments invoiced	5,000,000
Mitsubishi Tanabe Pharma Corporation \| Mitsubishi Tanabe Pharma Corporation Supply Agreement \| Contract With Customer, Liability
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up-front payments invoiced	$ 0

License, Collaboration and Other Significant Agreements - U.S. Collaboration and License Agreement with Otsuka Pharmaceutical Co. Ltd. (Details)		3 Months Ended
	Dec. 31, 2016 USD ($)	Mar. 31, 2022 USD ($) performance_obligation	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Apr. 01, 2019	Mar. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue		$ 61,699,000	$ 52,304,000
Deferred revenue		75,796,000
Short-term deferred revenue		10,440,000		$ 20,906,000
Deferred revenue, net of current portion		65,356,000		21,474,000
Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		24,316,000	3,539,000	19,094,000	$ 3,045,000
Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		3,970,000	1,916,000	4,309,000	1,722,000
Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue		319,000	0	3,171,000	$ 7,227,000
License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue		$ 20,251,000	21,896,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of performance obligations \| performance_obligation		3
Percentage of costs funded by customer						80.00%	52.50%
Collaborative arrangements additional cost sharing payments amount		$ 117,400,000
Transaction price		514,400,000
Reimbursement of costs	$ 33,800,000
Collaborative arrangements cost sharing payments		355,600,000
Deferred revenue		22,279,000
Short-term deferred revenue		6,192,000
Deferred revenue, net of current portion		16,087,000
Cost share costs incurred		7,600,000	1,000,000
Reimbursable costs		3,800,000	500,000
Cost share costs by partner for license agreement		0	300,000
Costs reimbursed			200,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Global Development Plan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangements additional cost sharing payments expected amount		$ 149,600,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reduction in percentage of future payments due upon current global development costs creditable		50.00%
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of remaining creditable amount applied to future payments		50.00%
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		$ 9,000,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		2,700,000		3,000,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue				$ 2,000,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue		5,638,000	$ 13,674,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| HIF Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments (up to)		65,000,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Licensed Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments (up to)		575,000,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Up Front Non Refundable And Non Creditable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received		125,000,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka U.S. Agreement \| Development And Regulatory Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone revenue		$ 0

License, Collaboration and Other Significant Agreements - International Collaboration and License Agreement with Otsuka Pharmaceutical Co. Ltd. (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) performance_obligation	Mar. 31, 2021 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue	$ 61,699	$ 52,304
Deferred revenue	75,796
Short-term deferred revenue	10,440			$ 20,906
Deferred revenue, net of current portion	65,356			21,474
Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable	24,316	3,539		19,094	$ 3,045
Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable	3,970	1,916		4,309	1,722
Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	319	0		3,171	$ 7,227
License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue	$ 20,251	21,896
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of performance obligations \| performance_obligation	3
Transaction price	$ 316,900
Reimbursement of costs			$ 200
Estimated current global development costs subsequent to March 31, 2017	243,700
Deferred revenue	10,221
Short-term deferred revenue	4,248
Deferred revenue, net of current portion	5,973
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Accounts receivable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable	11,300
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Prepaid expenses and other current assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable	1,200			1,300
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Accounts payable
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue				$ 900
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| License, collaboration and other revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Recognized revenue	5,503	$ 6,972
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Licensed HIF Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments (up to)	$ 17,000
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Licensed HIF Product \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments, period	12 months
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Licensed HIF Product \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments, period	24 months
Otsuka Pharmaceutical Company. Ltd. \| Otsuka International Agreement \| Licensed Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible milestone payments (up to)	$ 525,000
Otsuka Pharmaceutical Company. Ltd. \| Up Front Non Refundable And Non Creditable \| Otsuka International Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment received	$ 73,000

License, Collaboration and Other Significant Agreements - Janssen Pharmaceutica NV Research and License Agreement (Details) - Development And Commercialize Research And License Agreement $ in Millions	Feb. 09, 2017 USD ($) shares
Janssen Pharmaceutica NV
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangement, term	3 years
Upfront payment made in cash	$ 1.0
Potential milestone revenue from developmental milestones (up to)	16.5
Potential milestone revenue from commercial milestones (up to)	$ 215.0
Johnson & Johnson Innovation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrant to purchase common stock (in shares) \| shares	509,611

License, Collaboration and Other Significant Agreements - Cyclerion Therapeutics License Agreement (Details) - Cyclerion Therapeutics License Agreement $ in Millions	Jun. 04, 2021 USD ($)
Asset Acquisition [Line Items]
Upfront payment for asset acquisition	$ 3.0
Contingent consideration from developmental and regulatory milestones	$ 222.0

License, Collaboration and Other Significant Agreements - Vifor Pharma License Agreement (Details) $ / shares in Units, $ in Thousands						3 Months Ended
	Feb. 22, 2022 USD ($) $ / shares shares	Feb. 18, 2022 USD ($)	Feb. 14, 2020 USD ($)	Apr. 08, 2019 USD ($)	May 12, 2017 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) performance_obligation $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment						$ 75,796
Common stock, issued (in shares) \| shares						183,386,035	177,000,963
Common stock, par value (in dollars per share) \| $ / shares	$ 0.00001					$ 0.00001	$ 0.00001
Current portion of refund liability to customer						$ 16,500	$ 0
Vifor (International) Ltd.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract termination, prior written notice period		30 months
Contract termination, period subsequent complete response letter		30 days
Private Placement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of shares sold in offering (in shares) \| shares	4,000,000
Aggregate net proceeds from offering	$ 20,000
Aggregate net proceeds from offering, fair value in excess of carrying amount	$ 13,600
Vifor (International) Ltd.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract termination, prior written notice period		6 months
Refund liability to customer, gross						40,000
Refund liability to customer, net of deferred gain and discount						$ 39,900
Vifor (International) Ltd. \| License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue, remaining performance obligation, profit share percentage		66.00%
Upfront payment		$ 25,000
Number of performance obligations \| performance_obligation						1
Refund liability to customer, purchase orders to total						50.00%
Refund liability to customer, interest rate						15.00%
Vifor (International) Ltd. \| License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone revenue				$ 25,000
Common stock, issued (in shares) \| shares					3,571,429
Sale of stock, price per share (in dollars per share) \| $ / shares					$ 14.00
Proceeds from common stock sold					$ 50,000
Premium over the closing stock price of common stock (in dollars per share) \| $ / shares					$ 12.69
Premium amount over the closing stock price of common stock					$ 4,700
Vifor (International) Ltd. \| Priority Review Voucher Letter Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payments for closing Priority Review Voucher purchase			$ 10,000
Proceeds from collaborators							$ 8,600

License, Collaboration and Other Significant Agreements - License Agreement with Panion & BF Biotech, Inc. (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
JT and Torii \| Panion & BF Biotech, Incorporation \| License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty payments	$ 2.5	$ 2.5

License, Collaboration and Other Significant Agreements - Sublicense Agreement with Japan Tobacco, Inc. and its subsidiary, Torii Pharmaceutical Co., Ltd. (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) performance_obligation	Mar. 31, 2021 USD ($)
License, Collaboration and Other Revenue:
Recognized revenue	$ 61,699	$ 52,304
JT and Torii \| Sublicense Agreement
License, Collaboration and Other Revenue:
Number of performance obligations \| performance_obligation	2
Recognized revenue	$ 1,100	$ 1,200

- Definition

+ References

+ Details

Liability Related to Sale of Future Royalties - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 25, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Other Liabilities Disclosure [Abstract]
Maximum annual royalty payout capacity	$ 13,000
Maximum aggregate royalty payout capacity	150,000
Proceeds from sale of future royalties, net	44,800	$ 0	$ 44,783
Liability related to sale of future royalties, net	$ 44,800	$ 55,095		$ 53,079
Annual effective interest rate		17.70%

Liability Related to Sale of Future Royalties - Rollforward of Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Contractual Arrangement, Royalties Agreement, Liability, Noncurrent [Roll Forward]
Liability related to sale of future royalties, net beginning balance at December 31, 2021	$ 53,079
MTPC royalties payable	(329)
Non-cash interest expense recognized	2,345	$ 2,162
Liability related to sale of future royalties, net — ending balance	$ 55,095

Fair Value of Financial Instruments - Assets Measured or Disclosed at Fair Value on Recurring Basis (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Liabilities:
Derivative liability	$ 1,110,000	$ 1,820,000
Level 3
Assets:
Total assets fair value disclosure	0	0
Fair value measurements recurring
Assets:
Cash and cash equivalents	174,562,000	149,800,000
Total assets fair value disclosure	174,562,000	149,800,000
Liabilities:
Derivative liability	1,110,000	1,820,000
Total liabilities fair value disclosure	1,110,000	1,820,000
Fair value measurements recurring \| Level 1
Assets:
Cash and cash equivalents	174,562,000	149,800,000
Total assets fair value disclosure	174,562,000	149,800,000
Liabilities:
Derivative liability	0	0
Total liabilities fair value disclosure	0	0
Fair value measurements recurring \| Level 2
Assets:
Cash and cash equivalents	0	0
Total assets fair value disclosure	0	0
Liabilities:
Derivative liability	0	0
Total liabilities fair value disclosure	0	0
Fair value measurements recurring \| Level 3
Assets:
Cash and cash equivalents	0	0
Total assets fair value disclosure	0	0
Liabilities:
Derivative liability	1,110,000	1,820,000
Total liabilities fair value disclosure	$ 1,110,000	$ 1,820,000

Fair Value of Financial Instruments - Additional Information (Details)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability	$ 1,110,000	$ 1,820,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on recurring basis	$ 0	0
Level 3 \| Measurement Input, Clinical Development Success \| Valuation, Market Approach
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0
Level 3 \| Other than Derivative Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on recurring basis	$ 0	0
Collateral Agent, Pharmakon
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability	$ 1,100,000	$ 1,800,000

Fair Value of Financial Instruments - Fair Value Derivative Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Liability, Fair Value, Gross Liability [Roll Forward]
Balance at beginning of period	$ 1,820
Change in fair value of derivative liability, recorded as other expense (income)	(710)	$ 80
Balance at end of period	$ 1,110

Inventory - Components of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
Raw materials	$ 678	$ 1,763
Work in process	74,025	62,635
Finished goods	8,207	14,661
Total inventory	82,910	79,059
Balance Sheet Classification:
Inventory	39,422	38,195
Other assets	$ 43,488	$ 40,864

Inventory - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Business Acquisition [Line Items]
Inventory amounts written down	$ 5,344	$ 5,075
Inventory adjustments to previous reserves	3,200
Keryx Biopharmaceuticals, Inc.
Business Acquisition [Line Items]
Inventory step-up charges	$ 0	$ 8,700

Intangible Assets and Goodwill - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 213,603	$ 213,603
Accumulated Amortization	(114,487)	(105,476)
Total	99,116	108,127
Developed product rights for Auryxia
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	213,603	213,603
Accumulated Amortization	(114,487)	(105,476)
Total	$ 99,116	$ 108,127
Finite-Lived Intangible Asset, Useful Life	6 years

Intangible Assets and Goodwill - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022 USD ($) segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 9,011,000	$ 9,011,000
Goodwill	$ 55,053,000		$ 55,053,000
Number of operating segments \| segment	1
Goodwill impairment	$ 0
Developed product rights for Auryxia
Finite-Lived Intangible Assets [Line Items]
Intangible assets, estimated useful life	6 years

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Product revenue allowances	$ 26,236	$ 26,624
Accrued clinical	16,710	14,036
Collaborative arrangement accrued liability	28,019	22,654
Accrued payroll and related	7,130	15,863
Lease liability	$ 4,763	$ 4,802
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total accrued expenses	Total accrued expenses
Royalties	$ 3,175	$ 3,472
Professional fees	2,711	1,899
Accrued commercial manufacturing	3,884	3,843
Accrued other	17,032	11,263
Total accrued expenses	$ 109,660	$ 104,456

Debt (Details)			3 Months Ended
Debt (Details)	Dec. 10, 2020 USD ($)	Nov. 11, 2019 USD ($) tranche	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Nov. 25, 2019 USD ($)
Line of Credit Facility [Line Items]
Derivative liability			$ 1,110,000		$ 1,820,000
Collateral Agent, Pharmakon
Line of Credit Facility [Line Items]
Derivative liability			1,100,000		$ 1,800,000
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity		$ 100,000,000
Line of credit, maximum borrowing capacity, number of available tranches \| tranche		2
Term loan, maturity term		5 years
Term loan, maturity term, potential reduction (up to)		1 year
Term loan, amortization period, potential reduction (up to)		1 year
Facility fee percentage on principal amount		2.00%
Facility fee paid, amount		$ 2,000,000
Prepayment premium percentage on principal if prepaid prior to third anniversary of funding		2.00%
Prepayment premium percentage on principal if prepaid prior to fourth anniversary and after third anniversary of funding		1.00%
Prepayment premium percentage on principal if prepaid after fourth anniversary of funding		0.50%
Interest expense			$ 2,700,000	$ 2,700,000
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| Debt Instrument, Quarterly Periodic Payment, Period One
Line of Credit Facility [Line Items]
Term loan, first quarterly principal payment due in		33 months
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| Debt Instrument, Quarterly Periodic Payment, Period Two
Line of Credit Facility [Line Items]
Term loan, first quarterly principal payment due in		48 months
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| Three-month LIBOR
Line of Credit Facility [Line Items]
Basis spread on floating interest rate		7.50%
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| LIBOR
Line of Credit Facility [Line Items]
Debt instrument, floor rate		2.00%
Debt instrument, cap rate		3.35%
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| Tranche A
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity		$ 80,000,000
Term loan, net of facility fees, lender expenses and issuance costs						$ 77,300,000
Biopharma Credit Investments V (Master) LP \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| Tranche B
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity		$ 20,000,000
BPCR Limited Partnership \| Keryx \| Term Loan \| Collateral Agent, Pharmakon \| Tranche B
Line of Credit Facility [Line Items]
Proceeds from line of credit	$ 20,000,000

Warrant (Details) - Janssen Agreement $ / shares in Units, $ in Millions	Feb. 28, 2017 USD ($) $ / shares shares
Class of Warrant or Right [Line Items]
Warrant to purchase common stock (in shares) \| shares	509,611
Exercise price (in dollars per share) \| $ / shares	$ 9.81
Fair value of warrant at issuance \| $	$ 3.4

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands				3 Months Ended			4 Months Ended	10 Months Ended
	Mar. 01, 2022 USD ($)	Feb. 25, 2021 USD ($)	Mar. 12, 2020 USD ($)	Mar. 31, 2022 USD ($) installment $ / shares shares	Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($) shares	May 09, 2022 USD ($) shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) shares	Feb. 22, 2022 $ / shares	Jun. 04, 2020 shares	Feb. 28, 2014 shares
Class of Stock [Line Items]
Common stock, authorized (in shares)				350,000,000				350,000,000			175,000,000
Common stock, par value (in dollars per share) \| $ / shares				$ 0.00001				$ 0.00001		$ 0.00001
Common stock, issued (in shares)				183,386,035				177,000,963
Common stock, outstanding (in shares)				183,386,035				177,000,963
Preferred stock, shares authorized (in shares)				25,000,000				25,000,000
Preferred stock, par value (in dollars per share) \| $ / shares				$ 0.00001				$ 0.00001
Preferred stock, issued (in shares)				0				0
Preferred stock, outstanding (in shares)				0				0
Proceeds from the issuance of common stock, net of issuance costs \| $				$ 7,178		$ 29,327
Inducement Award Program
Class of Stock [Line Items]
Number of shares granted				279,000
Number of shares outstanding				279,000
Share-based Payment Arrangement, Option
Class of Stock [Line Items]
Expiration period				10 years
Share-based Payment Arrangement, Option \| Share-based Compensation Award, Tranche, First Anniversary of Grant Date
Class of Stock [Line Items]
Vesting percentage				100.00%
Share-based Payment Arrangement, Option \| Share Based Compensation Award Tranche One
Class of Stock [Line Items]
Vesting period				1 year
Vesting percentage				25.00%
Share-based Payment Arrangement, Option \| Share Based Compensation Award Tranche Two
Class of Stock [Line Items]
Vesting period				1 year
Number of equal quarterly installments \| installment				12
Service-Based Restricted Stock Units \| Share Based Compensation Award Tranche One
Class of Stock [Line Items]
Vesting period				1 year
Vesting percentage				50.00%
Service-Based Restricted Stock Units \| Share Based Compensation Award Tranche Two
Class of Stock [Line Items]
Vesting period				6 months
Vesting percentage				25.00%
Award vesting grace period				1 year
Service-Based Restricted Stock Units \| Share-based Compensation Award, Tranche, First Or Third Anniversary of Grant Date
Class of Stock [Line Items]
Vesting percentage				100.00%
Service-Based Restricted Stock Units \| Share-Based Payment Arrangement, Tranche One, First Anniversary After Grant Date, Subjected To Individual Continued Service
Class of Stock [Line Items]
Vesting period				1 year
Vesting percentage				33.33%
Service-Based Restricted Stock Units \| Share-Based Payment Arrangement, Tranche Two, Second Anniversary After Grant Date, Subjected To Individual Continued Service
Class of Stock [Line Items]
Vesting period				2 years
Vesting percentage				33.33%
Service-Based Restricted Stock Units \| Share-Based Payment Arrangement, Tranche Three, Third Anniversary After Grant Date, Subjected To Individual Continued Service
Class of Stock [Line Items]
Vesting period				3 years
Vesting percentage				33.33%
Common Stock
Class of Stock [Line Items]
Common stock, outstanding (in shares)				183,386,035		158,520,089		177,000,963	148,074,085
Issuance of common stock, net of issuance costs (in shares)				4,404,600		9,228,017
Common Stock \| At The Market Equity Offering Program Authorized February 2021
Class of Stock [Line Items]
Issuance of common stock, net of issuance costs (in shares)								21,128,065
Proceeds from the issuance of common stock, net of issuance costs \| $								$ 72,400
Common Stock \| At The Market Equity Offering Program Authorized March 2022 \| Subsequent Event
Class of Stock [Line Items]
Issuance of common stock, net of issuance costs (in shares)							404,600
Proceeds from the issuance of common stock, net of issuance costs \| $							$ 800
Minimum \| Share-based Payment Arrangement, Option
Class of Stock [Line Items]
Vesting period				12 months
Minimum \| Service-Based Restricted Stock Units \| Share-based Compensation Award, Tranche, First Or Third Anniversary of Grant Date
Class of Stock [Line Items]
Vesting period				1 year
Maximum \| At The Market Equity Offering Program Authorized February 2021
Class of Stock [Line Items]
Common stock sales agreement amount \| $		$ 100,000
Maximum \| At The Market Equity Offering Program Authorized March 2022
Class of Stock [Line Items]
Common stock sales agreement amount \| $	$ 25,300
Maximum \| Share-based Payment Arrangement, Option
Class of Stock [Line Items]
Vesting period				48 months
Maximum \| Service-Based Restricted Stock Units \| Share-based Compensation Award, Tranche, First Or Third Anniversary of Grant Date
Class of Stock [Line Items]
Vesting period				3 years
At The Market Equity Offering Program \| Common Stock
Class of Stock [Line Items]
Issuance of common stock, net of issuance costs (in shares)						5,224,278			3,509,381
Proceeds from the issuance of common stock, net of issuance costs \| $					$ 15,900				$ 10,600
At The Market Equity Offering Program \| Maximum
Class of Stock [Line Items]
Common stock sales agreement amount \| $			$ 65,000
2014 Plans
Class of Stock [Line Items]
Common stock, reserved for future issuance (in shares)												1,785,000
Incremental rate at which the shares reserved for issuance increase				3.00%
2014 Plans \| Share-based Payment Arrangement, Option \| Employees
Class of Stock [Line Items]
Number of shares granted				2,833,500
2014 Plans \| Performance Shares
Class of Stock [Line Items]
Number of shares granted				0
2014 Plans \| Service-Based Restricted Stock Units \| Employees
Class of Stock [Line Items]
Number of shares granted (in shares)				2,914,308
2014 Plans \| Performance-Based Restricted Stock Units
Class of Stock [Line Items]
Number of shares granted (in shares)				0
2014 Employee Stock Purchase Plan
Class of Stock [Line Items]
Common stock, reserved for future issuance (in shares)				4,981,995
Offering period				6 months
Purchase price at the end of offering period				85.00%
Number of shares issued				191,146

Commitments and Contingencies - Additional Information (Details)						1 Months Ended					3 Months Ended
	Feb. 10, 2021	Sep. 04, 2020	Apr. 02, 2020	Apr. 09, 2019	Jan. 01, 2017 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020	Feb. 28, 2019 USD ($)	Jul. 31, 2016 USD ($) ft²	Mar. 31, 2022 USD ($) ft² extensionOption	Mar. 31, 2021 USD ($)	Nov. 30, 2020 ft²	Apr. 30, 2018 ft²
Commitments And Contingencies [Line Items]
Operating lease, cost											$ 1,800,000	$ 1,700,000
Operating lease, payments											1,800,000	1,800,000
Increase (decrease) in purchase commitments											(773,000)	(8,945,000)
Inventory adjustments to previous reserves											3,200,000
Total remaining contract costs											4,700,000
Contract cost incurred in research and development activities											211,900,000
Supply Agreement, Patheon Inc.
Commitments And Contingencies [Line Items]
Minimum purchase commitment											3,900,000
BioVectra Inc
Commitments And Contingencies [Line Items]
Long-term minimum purchase commitment renewal term		1 year
Cost of purchased minimum quantity product											83,600,000
Siegfried Evionnaz SA
Commitments And Contingencies [Line Items]
Cost of purchased minimum quantity product											$ 13,500,000
Purchase commitment, option to extend, prior notice period											12 months
Esteve Química, S.A
Commitments And Contingencies [Line Items]
Initial term of supply agreement				4 years
Long-term minimum purchase commitment											$ 39,000,000
STA Pharmaceutical Hong Kong Limited
Commitments And Contingencies [Line Items]
Long-term minimum purchase commitment											$ 77,900,000
Minimum purchase commitment, initial term			4 years
WuXi STA
Commitments And Contingencies [Line Items]
Purchase commitment, option to extend, prior notice period	18 months
Minimum purchase commitment, initial term	4 years
Long-term purchase commitment, fixed price, period	12 months
Long-term purchase commitment, option to terminate, prior notice period (at least)	180 days
Minimum
Commitments And Contingencies [Line Items]
Operating lease, incremental borrowing rates based on remaining lease term											6.65%
Operating lease, remaining lease term											4 years 5 months 12 days
Maximum
Commitments And Contingencies [Line Items]
Operating lease, incremental borrowing rates based on remaining lease term											7.25%
Operating lease, remaining lease term											9 years 4 months 2 days
Keryx Biopharmaceuticals, Inc.
Commitments And Contingencies [Line Items]
Preliminary fair value of the off-market element							$ 76,700,000				$ 72,700,000
Cambridge
Commitments And Contingencies [Line Items]
Area of property leased (in square feet) \| ft²										45,362			65,167
Annual lease expense										$ 242,000
Monthly lease expense					$ 22,000
Cambridge \| Letter of Credit \| Other Assets
Commitments And Contingencies [Line Items]
Total security deposit in connection with lease											$ 1,600,000
Cambridge \| Office Space
Commitments And Contingencies [Line Items]
Area of property leased (in square feet) \| ft²														19,805
Monthly lease expense							$ 48,000		$ 135,000
Operating lease, free monthly rent, period								2 months
Lease period, number of extension options \| extensionOption											1
Lease extension period											5 years
Boston \| Keryx Biopharmaceuticals, Inc. \| Letter of Credit \| Other Assets
Commitments And Contingencies [Line Items]
Total security deposit in connection with lease											$ 1,400,000
Boston \| Office Space
Commitments And Contingencies [Line Items]
Area of property leased (in square feet) \| ft²											27,300
Monthly lease expense						$ 200,122					$ 136,000
Operating lease, free monthly rent, period						5 months
Operating lease, annual rent escalation, percentage						2.00%
Operating lease, allowance for leasehold improvements						$ 1,954,680
Boston \| Office Space \| Keryx Biopharmaceuticals, Inc.
Commitments And Contingencies [Line Items]
Lease period, number of extension options \| extensionOption											1
Lease extension period											5 years
Sublease rental income											$ 500,000	$ 400,000

Commitments and Contingencies - Undiscounted Minimum Rental Commitments Under Non-Cancelable Leases (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Operating Leases
Remaining 2022	$ 5,502
2023	6,954
2024	8,167
2025	8,293
2026	6,571
Thereafter	12,200
Total	47,687
Lease Payments to be Received from Sublease
Remaining 2022	1,370
2023	307
2024	0
2025	0
2026	0
Thereafter	0
Total	1,677
Net Operating Lease Payments
Remaining 2022	4,132
2023	6,647
2024	8,167
2025	8,293
2026	6,571
Thereafter	12,200
Total	$ 46,010

Commitments and Contingencies - Difference Between Undiscounted Minimum Rental Commitments Under Non-Cancelable Leases and Operating Leases Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Total	$ 47,687
Present value adjustment using incremental borrowing rate	(10,006)
Operating lease liabilities	$ 37,681
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued expenses and other current liabilities	Accrued expenses and other current liabilities

Net Loss per Share - Anti-Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	19,970,534	18,402,397
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	0	509,611
Share-based Payment Arrangement, Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	14,187,899	11,369,546
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	5,782,635	6,523,240

Subsequent Events (Details) - Subsequent Event - USD ($) $ in Millions	Apr. 07, 2022	Apr. 04, 2022
Subsequent Event [Line Items]
Percentage for workforce approved for elimination, exclusive of open positions		42.00%
Percentage for workforce approved for elimination, inclusive of open positions		47.00%
Expected restructuring cost		$ 16.5
Maximum \| Open Market Sale Agreement, Authorized April 2022
Subsequent Event [Line Items]
Common stock sales agreement amount	$ 26.0