0000950170-23-058914 | 10-Q | XBRL Viewer

Net Loss Per Share

9 Months Ended

Sep. 30, 2023

Note 2 — Net Loss Per Share

The following instruments were excluded from the computation of diluted net loss per share for the periods presented because their effect would have been antidilutive (in thousands):


	September 30, 2023		September 30, 2022
Options to purchase common stock		12,163		10,838
Warrants to purchase common stock		13		13
Restricted stock and performance units		1,401		1,275
Shares issuable related to the ESPP		64		41
Shares issuable upon conversion of 2026 Notes		2,554		2,554
Shares issuable upon conversion of 2027 Notes		13,744		10,572
Total shares		29,939		25,293

Agreements with Royalty Pharma - Schedule Represents Allocation of Transaction Consideration on a Relative Fair Value Basis to the Liability and the Common Stock (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
RP Aficamten Liability [Member]
Royalty Liability [Line Items]
Liabilities related to revenue participation right purchase agreements, net beginning balance	$ 115,383	$ 110,480	$ 105,117	$ 94,431	$ 91,857	$ 0	$ 105,117	$ 0
Initial carrying value			0			89,571
Additional consideration	50,000
Interest accretion	5,415	4,903	5,363	5,469	2,574	2,286
Amortization of issuance costs		0	0		0	0
Liabilities related to revenue participation right purchase agreements, net ending balance	170,798	115,383	110,480	99,900	94,431	91,857	170,798	99,900
RPOM Liability [Member]
Royalty Liability [Line Items]
Liabilities related to revenue participation right purchase agreements, net beginning balance	197,780	196,334	195,384	187,835	183,378	179,072	195,384	179,072
Initial carrying value			0			0
Interest accretion	1,445	1,419	917	3,494	4,429	4,278
Amortization of issuance costs	26	27	33	31	28	28
Liabilities related to revenue participation right purchase agreements, net ending balance	$ 199,251	$ 197,780	$ 196,334	$ 191,360	$ 187,835	$ 183,378	$ 199,251	$ 191,360

Fair Value Measurements

9 Months Ended

Sep. 30, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 4 — Fair Value Measurements

We value our financial assets and liabilities at fair value, defined as the price that would be received for assets when sold or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We utilize market data or assumptions that we believe market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable.

We primarily apply the market approach for recurring fair value measurements and endeavor to utilize the best information reasonably available. Accordingly, we use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible and consider the security issuers’ and the third-party issuers’ credit risk in our assessment of fair value.

We classify fair value based on the observability of those inputs using a hierarchy that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement):

Level 1 — Observable inputs, such as quoted prices in active markets for identical assets or liabilities;

Level 2 — Inputs, other than the quoted prices in active markets, that are observable either directly or through corroboration with observable market data; and

Level 3 — Unobservable inputs, for which there is little or no market data for the assets or liabilities, such as internally-developed valuation models.

Fair Value of Financial Assets:

The follow tables set forth the fair value of our financial assets, which consists of cash equivalents and investments classified as available-for-sale securities, that were measured on a recurring basis (in thousands):


		September 30, 2023
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	56,714	$	—	$	—		$	56,714
U.S. Treasury securities	Level 1		55,029		3		(42	)		54,990
U.S. Government agency securities	Level 2		167,184		45		(309	)		166,920
Commercial paper	Level 2		219,468		4		(209	)		219,263
Corporate obligations	Level 2		52,825		—		(366	)		52,459
		$	551,220	$	52	$	(926	)	$	550,346


		December 31, 2022
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	45,887	$	—	$	—		$	45,887
U.S. Treasury securities	Level 1		172,568		—		(1,102	)		171,466
U.S. Treasury securities backed repurchase agreements	Level 2		16,003		—		—			16,003
U.S. Government agency securities	Level 2		129,174		12		(820	)		128,366
Foreign government agency securities	Level 2		7,599		—		(69	)		7,530
Commercial paper	Level 2		329,359		28		(431	)		328,956
Corporate obligations	Level 2		128,594		—		(1,209	)		127,385
		$	829,184	$	40	$	(3,631	)	$	825,593

No credit losses on debt securities were recognized during the nine months ended September 30, 2023 or 2022. In its evaluation to determine expected credit losses, management considered all available historical and current information, expectations of future economic conditions, the type of security, the credit rating of the security, and the size of the loss position, as well as other relevant information. The Company does not intend to sell, and is unlikely to be required to sell, any of these available-for-sale investments before their effective maturity or market price recovery.

- 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

Organization and Significant Accounting Policies	9 Months Ended
Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Significant Accounting Policies	Note 1 — Organization and Significant Accounting Policies Cytokinetics, Incorporated was incorporated under the laws of the state of Delaware on August 5, 1997. The Company is a late-stage biopharmaceutical company focused on the discovery and development of novel small molecule therapeutics that modulate muscle function for the potential treatment of serious diseases and medical conditions. Our financial statements contemplate the conduct of our operations in the normal course of business. We have incurred an accumulated deficit of approximately $2.0 billion since inception and there can be no assurance that we will attain profitability. We had a net loss of $389.3 million and net cash used in operations of $340.3 million for the nine months ended September 30, 2023. Cash, cash equivalents, and investments decreased to $554.7 million as of September 30, 2023 from $829.3 million as of December 31, 2022. We anticipate that we will have operating losses and net cash outflows in future periods. We are subject to risks common to late-stage biopharmaceutical companies including, but not limited to, development of new drug candidates, dependence on key personnel, and the ability to obtain additional capital as needed to fund our future plans. Our liquidity will be impaired if sufficient additional capital is not available on terms acceptable to us. To date, we have funded operations primarily through sales of our common stock, contract payments under our collaboration agreements, sales of future revenues and royalties, debt financing arrangements, government grants and interest income. Until we achieve profitable operations, we intend to continue to fund operations through payments from strategic collaborations, additional sales of equity securities, grants and debt financings. We have never generated revenues from commercial sales of our drugs and may not have drugs to market for at least several years, if ever. Our success is dependent on our ability to enter into new strategic collaborations and/or raise additional capital and to successfully develop and market one or more of our drug candidates. We cannot be certain that sufficient funds will be available from such a financing or through a collaborator when required or on satisfactory terms. Additionally, there can be no assurance that our drug candidates will be accepted in the marketplace or that any future products can be developed or manufactured at an acceptable cost. These factors could have a material adverse effect on our future financial results, financial position and cash flows. Based on the current status of our research and development activities, we believe that our existing cash, cash equivalents and investments will be sufficient to fund cash requirements for at least the next 12 months after the issuance of this Quarterly Report on Form 10-Q. If, at any time, our prospects for financing our research and development programs decline, we may decide to reduce research and development expenses by delaying, discontinuing or reducing our funding of one or more of our research or development programs. Alternatively, we might raise funds through strategic collaborations, public or private financings or other arrangements. Such funding, if needed, may not be available on favorable terms, or at all. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. Basis of Presentation Our condensed consolidated financial statements include the accounts of Cytokinetics and our wholly-owned subsidiaries. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. The financial statements include all adjustments (consisting only of normal recurring adjustments) that management believes are necessary for the fair statement of our financial information. These interim results are not necessarily indicative of results to be expected for the full fiscal year or any future interim period. The balance sheet as of December 31, 2022 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by GAAP for complete financial statements. The financial statements and related disclosures have been prepared with the presumption that users of the interim financial statements have read or have access to the audited financial statements for the preceding fiscal year. Accordingly, these financial statements should be read in conjunction with the audited financial statements and notes thereto contained in the Company’s Form 10-K for the year ended December 31, 2022, as filed with the Securities and Exchange Commission. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. We evaluate our estimates on an ongoing basis. We base our estimates on our historical experience and also on assumptions that we believe are reasonable; however, actual results could significantly differ from those estimates.

Organization and Significant Accounting Policies

9 Months Ended

Sep. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Significant Accounting Policies

Note 1 — Organization and Significant Accounting Policies

Cytokinetics, Incorporated was incorporated under the laws of the state of Delaware on August 5, 1997. The Company is a late-stage biopharmaceutical company focused on the discovery and development of novel small molecule therapeutics that modulate muscle function for the potential treatment of serious diseases and medical conditions.

Our financial statements contemplate the conduct of our operations in the normal course of business. We have incurred an accumulated deficit of approximately $2.0 billion since inception and there can be no assurance that we will attain profitability. We had a net loss of $389.3 million and net cash used in operations of $340.3 million for the nine months ended September 30, 2023. Cash, cash equivalents, and investments decreased to $554.7 million as of September 30, 2023 from $829.3 million as of December 31, 2022. We anticipate that we will have operating losses and net cash outflows in future periods.

We are subject to risks common to late-stage biopharmaceutical companies including, but not limited to, development of new drug candidates, dependence on key personnel, and the ability to obtain additional capital as needed to fund our future plans. Our liquidity will be impaired if sufficient additional capital is not available on terms acceptable to us. To date, we have funded operations primarily through sales of our common stock, contract payments under our collaboration agreements, sales of future revenues and royalties, debt financing arrangements, government grants and interest income. Until we achieve profitable operations, we intend to continue to fund operations through payments from strategic collaborations, additional sales of equity securities, grants and debt financings. We have never generated revenues from commercial sales of our drugs and may not have drugs to market for at least several years, if ever. Our success is dependent on our ability to enter into new strategic collaborations and/or raise additional capital and to successfully develop and market one or more of our drug candidates. We cannot be certain that sufficient funds will be available from such a financing or through a collaborator when required or on satisfactory terms. Additionally, there can be no assurance that our drug candidates will be accepted in the marketplace or that any future products can be developed or manufactured at an acceptable cost. These factors could have a material adverse effect on our future financial results, financial position and cash flows.

Based on the current status of our research and development activities, we believe that our existing cash, cash equivalents and investments will be sufficient to fund cash requirements for at least the next 12 months after the issuance of this Quarterly Report on Form 10-Q. If, at any time, our prospects for financing our research and development programs decline, we may decide to reduce research and development expenses by delaying, discontinuing or reducing our funding of one or more of our research or development programs. Alternatively, we might raise funds through strategic collaborations, public or private financings or other arrangements. Such funding, if needed, may not be available on favorable terms, or at all. The financial statements do not include any adjustments that might result from the outcome of this uncertainty.

Basis of Presentation

Our condensed consolidated financial statements include the accounts of Cytokinetics and our wholly-owned subsidiaries. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. The financial statements include all adjustments (consisting only of normal recurring adjustments) that management believes are necessary for the fair statement of our financial information. These interim results are not necessarily indicative of results to be expected for the full fiscal year or any future interim period. The balance sheet as of December 31, 2022 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by GAAP for complete financial statements. The financial statements and related disclosures have been prepared with the presumption that users of the interim financial statements have read or have access to the audited financial statements for the preceding fiscal year. Accordingly, these financial statements should be read in conjunction with the audited financial statements and notes thereto contained in the Company’s Form 10-K for the year ended December 31, 2022, as filed with the Securities and Exchange Commission.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. We evaluate our estimates on an ongoing basis. We base our estimates on our historical experience and also on assumptions that we believe are reasonable; however, actual results could significantly differ from those estimates.

Debt - Schedule of Interest Cost Relating to 2026 and 2027 Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
2026 Notes [Member]
Debt Instrument [Line Items]
Contractual interest expense	$ 211	$ 294	$ 633	$ 3,054
Amortization of debt issuance costs	29	19	79	328
Total interest expense recognized	240	313	712	3,382
2027 Notes [Member]
Debt Instrument [Line Items]
Contractual interest expense	4,726	4,462	14,175	4,462
Amortization of debt issuance costs	817	749	2,248	749
Total interest expense recognized	$ 5,543	$ 5,211	$ 16,423	$ 5,211

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (389,348)	$ (251,575)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash interest expense on liabilities related to revenue participation right purchase agreements	19,548	22,617
Stock-based compensation expense	52,578	34,355
Non-cash lease expense	2,808	1,502
Depreciation of property and equipment	5,557	4,156
Loss on investments, net	35	107
Interest receivable and amortization on investments	(10,634)	(492)
Non-cash interest expense related to debt	20,950	4,609
Loss on extinguishment of debt		2,693
Loss on inducement of convertible debt		22,246
Changes in operating assets and liabilities:
Accounts receivable	(2,352)	54,525
Prepaid and other assets	(6,937)	(8,942)
Accounts payable	(11,194)	(8,524)
Accrued and other liabilities	(15,026)	11,195
Operating lease liabilities	(272)	1,057
Other non-current liabilities	(6,009)	(3,855)
Deferred revenue		(87,000)
Net cash used in operating activities	(340,296)	(201,326)
Cash flows from investing activities:
Purchases of investments	(409,096)	(730,214)
Maturities of investments	726,122	446,961
Sales of investments	4,977
Purchases of property and equipment	(1,339)	(8,130)
Net cash provided by (used in) investing activities	320,664	(291,383)
Cash flows from financing activities:
Repayment of finance lease liabilities	(636)	(839)
Repayment of term loan		(47,651)
Debt extinguishment costs		(2,409)
Repayment of convertible debt		(140,330)
Proceeds from issuance of convertible debt, net		523,586
Proceeds from 2022 RPI Transactions, net	50,000	149,581
Proceeds from issuance of common stock related to at-the-market offering, net of issuance costs	1,312
Proceeds from issuance of common stock under equity incentive and stock purchase plans	12,358	13,945
Taxes paid related to net share settlement of equity awards	(10,517)	(9,602)
Net cash provided by financing activities	52,517	486,281
Net increase (decrease) in cash, cash equivalents, and restricted cash	32,885	(6,428)
Cash, cash equivalents, and restricted cash, beginning of period	67,182	112,666
Cash, cash equivalents, and restricted cash, end of period	100,067	106,238
Supplemental cash flow disclosures:
Cash paid for interest	$ 9,978	5,555
Non-cash investing and financing activities:
Right-of-use assets recognized in exchange for operating lease obligations		2,312
Right-of-use assets recognized in exchange for finance lease obligations		1,055
Amounts unpaid for purchases of property and equipment		1,866
Issuance of common stock in connection with repurchase of convertible note		$ 317,123

Research and Development Arrangements

9 Months Ended

Sep. 30, 2023

Research and Development [Abstract]

Research and Development Arrangements

Note 3 — Research and Development Arrangements

2021 Ji Xing and RTW Transactions

In December 2021, we entered into the 2021 RTW Transactions as described below, related to omecamtiv mecarbil.

Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement

On December 20, 2021, we entered into the Ji Xing OM License Agreement, pursuant to which we granted to Ji Xing an exclusive license to develop and commercialize omecamtiv mecarbil in China and Taiwan. Under the terms of the Ji Xing OM License Agreement, we are the beneficiary of a nonrefundable $50.0 million payment obligation from Ji Xing comprised of a $40.0 million payment as consideration for the rights granted by us to Ji Xing and $10.0 million attributable to our having submitted to the FDA an NDA for omecamtiv mecarbil. The $50.0 million payment was received by the Company in January 2022. We may be eligible to receive from Ji Xing additional payments totaling up to $330.0 million for the achievement of certain commercial milestone events in connection to omecamtiv mecarbil. In addition, Ji Xing will pay us tiered royalties in the mid-teens to the low twenties range on the net sales of pharmaceutical products containing omecamtiv mecarbil in China and Taiwan, subject to certain reductions for generic competition, patent expiration and payments for licenses to third party patents.

Ji Xing will be responsible for the development and commercialization of omecamtiv mecarbil at its own cost and is required to use diligent efforts to develop and commercialize omecamtiv mecarbil in China and Taiwan. The development of omecamtiv mecarbil will be initially focused on HFrEF, and Ji Xing will have the opportunity to participate in Cytokinetics’ global clinical trials of omecamtiv mecarbil. Cytokinetics will supply omecamtiv mecarbil to Ji Xing either as a finished product or as an active pharmaceutical ingredient. Ji Xing may reimburse Cytokinetics for certain costs related to development and supply activities that we perform on their behalf.

The Ji Xing OM License Agreement, unless terminated earlier, will continue on a market-by-market basis until expiration of the relevant royalty term. Ji Xing has the right to terminate the Ji Xing OM License Agreement for convenience. Each party may terminate the Ji Xing OM License Agreement for the other party’s uncured material breach, insolvency, or failure to perform due to extended force majeure events. Cytokinetics may also terminate the Ji Xing OM License Agreement if Ji Xing challenges Cytokinetics’ patents or undergoes certain change of control transactions. Rights granted to Ji Xing in relation to omecamtiv mecarbil will revert to Cytokinetics upon termination, and, under certain circumstances, subject to a low single digit royalty payment by the Company to Ji Xing on the net sales of the products containing the compound omecamtiv mecarbil in China and Taiwan. We assessed this arrangement in accordance with ASC 606 and concluded that there is one performance obligation relating to the license of functional intellectual property. The performance obligation was satisfied, and we recognized the residual allocation of arrangement consideration as revenue of $54.9 million in 2021. Due to the nature of development, including the inherent risk of development and approval by regulatory authorities, we are unable to estimate if and when the development milestone payments could be achieved or become due and, accordingly, we consider the milestone payments to be fully constrained and excluded any potential milestone payments from the initial transaction price.

The consideration related to sales-based milestone payments, including royalties, will be recognized when the related sales occur under the sales- and usage-based royalty exception as these amounts have been determined to relate predominantly to the license.

We re-evaluate the probability of achievement of development milestones and any related constraints each reporting period. We will include consideration, without constraint, in the transaction price to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur.

Common Stock Purchase Agreements

On December 20, 2021, as part of the 2021 RTW Transactions, we entered into common stock purchase agreements with each of the RTW Investors. These common stock purchase agreements provided for the sale and issuance of an aggregate of 511,182 shares of our common stock at a price per share of $39.125 and an aggregate purchase price of $20.0 million. The closing occurred on December 20, 2021. The RTW Investors have agreed to certain trading and other restrictions with respect to the shares of common stock they purchased pursuant to these agreements, including a restriction on sales or other transfers of the shares, subject to certain exceptions, for a period of one year from the closing date. The restrictions resulted in a premium paid by the RTW Investors of $4.9 million, which represents the excess amount paid over the fair value of the shares of common stock purchased. The premium was determined by analyzing the restrictions discount applied to the closing stock price as of December 20, 2021, which is a Level 2 fair value input. The cash received less the calculated premium is the $15.1 million fair value of the common stock recorded.

2020 Ji Xing and RTW Transactions

On July 14, 2020, we entered in the 2020 RTW Transactions, as described below, with RTW Royalty Holdings and Ji Xing, related to aficamten, our proprietary small molecule cardiac myosin inhibitor product, a novel cardiac myosin inhibitor, and other assets.

Ji Xing Aficamten License and Collaboration Agreement

On July 14, 2020, we entered into the Ji Xing Aficamten License Agreement with Ji Xing, pursuant to which we granted to Ji Xing an exclusive license to develop and commercialize aficamten in China and Taiwan. Under the terms of the Ji Xing Aficamten License Agreement, we received from Ji Xing a nonrefundable upfront payment of $25.0 million. We may be eligible to receive from Ji Xing milestone payments totaling up to $200.0 million for the achievement of certain development and commercial milestone events in connection to aficamten in the field of oHCM and/or nHCM and other indications. In addition, Ji Xing will pay us tiered royalties in the low-to-high teens range on the net sales of the products containing aficamten in China and Taiwan, subject to certain reductions for generic competition, patent expiration and payments for licenses to third party patents.

Ji Xing will be responsible for the development and commercialization of aficamten at its own cost and is required to use diligent efforts to develop and commercialize aficamten in China and Taiwan. The development of aficamten will be initially focused on HCM, and Ji Xing will have the opportunity to participate in Cytokinetics’ global pivotal clinical trials of aficamten. Cytokinetics or a designated supplier will supply aficamten to Ji Xing either as a finished product or as an active pharmaceutical ingredient.

The Ji Xing Aficamten License Agreement, unless terminated earlier, will continue on a market-by-market basis until expiration of the relevant royalty term. Ji Xing has the right to terminate the Ji Xing Aficamten License Agreement for convenience. Each party may terminate the Ji Xing Aficamten License Agreement for the other party’s uncured material breach, insolvency, or failure to perform due to extended force majeure events. Cytokinetics may also terminate the Ji Xing Aficamten License Agreement if Ji Xing challenges Cytokinetics’ patents or undergoes certain change of control transactions. Rights granted to Ji Xing in relation to aficamten will revert to Cytokinetics upon termination, and, under certain circumstances, subject to a low single digit royalty payment by the Company to Ji Xing on the net sales of the products containing the compound aficamten in China and Taiwan.

We assessed this arrangement in accordance with ASC 606 and concluded that there is one performance obligation relating to the license of functional intellectual property. The performance obligation was satisfied, and we recognized the residual allocation of arrangement consideration as revenue of $36.5 million for 2020. No license revenue was recognized in 2021 related to the Ji Xing Aficamten License Agreement. Due to the nature of development, including the inherent risk of development and approval by regulatory authorities, we are unable to estimate if and when the development milestone payments could be achieved or become due and, accordingly, we consider the milestone payments to be fully constrained and exclude the milestone payments from the initial transaction price.

The consideration related to sales-based milestone payments, including royalties, will be recognized when the related sales occur under the sales and usage-based royalty exception of ASC 606 as these amounts have been determined to relate predominantly to the license.

We recognized a $2.5 million milestone from Ji Xing during the nine months ended September 30, 2023 for the initiation of a phase 3 clinical trial for aficamten in nHCM and the $2.5 million is reflected in accounts receivable at September 30, 2023.

Royalty Purchase Agreement

On July 14, 2020, we entered the RTW Royalty Purchase Agreement with RTW Royalty Holdings, pursuant to which we sold our Mavacamten Royalty under the Research Collaboration Agreement, dated August 24, 2012, between us and MyoKardia, Inc. to RTW Royalty Holdings for a one-time payment of $85.0 million. The RTW Royalty Purchase Agreement transaction closed on November 13, 2020. On March 31, 2021, RTW Royalty Holdings assigned its rights and obligations under the RTW Royalty Purchase Agreement to its affiliate, RTW ICAV. We understand that on April 18, 2022, RTW ICAV and MyoKardia, Inc. entered into agreements, which purported to assign all of RTW ICAV's rights, title and interest to the Mavacamten Royalty to MyoKardia, Inc., and on April 25, 2022, we entered into a tripartite agreement with RTW ICAV and MyoKardia, Inc. acknowledging the release and discharge of any further obligations by us or MyoKardia, Inc. in connection to the Mavacamten Royalty.

The allocation of the consideration for the 2020 RTW Transactions resulted in $87.0 million being allocated to the RTW Royalty Purchase Agreement representing its fair value. The fair value was determined using an income approach method based on management’s estimates of the discounted cash flows to be received over the term of the related royalty agreement, which are Level 3 fair value inputs. Management’s estimates included significant unobservable inputs. These inputs are derived using internal management estimates developed based on third party data and reflect management’s judgments, current market conditions surrounding competing products, and forecasts. The significant unobservable inputs include the estimated patient population, estimated selling price, estimated peak sales and sales ramp, the expected term of the royalty stream, and timing of the expected launch. The $87.0 million was initially recorded as deferred revenue. On April 25, 2022, as discussed above, we entered into a tripartite agreement with RTW ICAV and MyoKardia, Inc. acknowledging the release and discharge of any further obligations by us or MyoKardia, Inc. in connection to the Mavacamten Royalty. As a result of the full extinguishment of the Mavacamten Royalty, we recognized revenue of $87.0 million in the three and nine months ended September 30, 2022.

Astellas

Our strategic alliance with Astellas to advance novel therapies for diseases and medical conditions associated with skeletal muscle impairment and weakness commenced in 2013 under the Astellas Agreement.

On April 23, 2020, we and Astellas entered into the two agreements referenced below which, taken together, amend and restate the Company’s research, development and commercialization collaboration with Astellas under the Astellas Agreement.

Fast Skeletal Regulatory Activator Agreement

The Company and Astellas entered into the Astellas FSRA Agreement on April 23, 2020. As a result of the Astellas FSRA Agreement, the Company will now have exclusive control and responsibility for the Company's future development and commercialization of reldesemtiv, CK-601 and other FSRA compounds and products, and accordingly, Astellas has agreed to terminate its license to all FSRA compounds and related products.

Under the Astellas FSRA Agreement, Astellas agreed to pay one-third of the out-of-pocket clinical development costs which may be incurred in connection with the Company’s Phase 3 clinical trial of reldesemtiv in ALS, up to a maximum contribution by Astellas of $12 million. As of June 30, 2023, we have billed Astellas up to the maximum contribution of $12.0 million. In addition, Astellas agreed to non-cash contributions to the Company, which included the transfer of its existing inventories of active pharmaceutical ingredient of reldesemtiv and CK-601.

On March 31, 2023, we announced that we will discontinue COURAGE-ALS, our Phase 3 clinical trial of reldesemtiv in patients with ALS, and COURAGE-ALS OLE.

We had no research and development revenue from Astellas for the three months ended September 30, 2023. Research and development revenue from Astellas was $2.5 million for the three months ended September 30, 2022, and $2.7 million and $4.6 million for the nine months ended September 30, 2023 and 2022, respectively.

We had no accounts receivable from Astellas as of September 30, 2023 or December 31, 2022.

Balance Sheet Components

9 Months Ended

Sep. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Components

Note 5 — Balance Sheet Components

A reconciliation of cash, cash equivalents, and restricted cash reported in the accompanying condensed consolidated balance sheets to the amount reported within the accompanying condensed consolidated statements of cash flows was as follows (in thousands):


	September 30, 2023		December 31, 2022
Cash and cash equivalents	$	99,692	$	65,582
Restricted cash		375		1,600
Total cash, cash equivalents, and restricted cash as reported within our consolidated statement of cash flows	$	100,067	$	67,182

As of September 30, 2023, our restricted cash balance of $0.4 million is used to collateralize letters of credit.

Accrued liabilities were as follows (in thousands):


	September 30, 2023		December 31, 2022
Accrued liabilities:
Clinical and preclinical costs	$	4,327	$	16,105
Compensation related		22,352		21,767
Other accrued expenses		6,275		6,224
Total accrued liabilities	$	32,954	$	44,096

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Common stock, par value	$ 0.001	$ 0.001

Fair Value Measurements - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Credit losses on debt securities	$ 0	$ 0

Balance Sheet Components - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accrued liabilities:
Clinical and preclinical costs	$ 4,327	$ 16,105
Compensation related	22,352	21,767
Other accrued expenses	6,275	6,224
Total accrued liabilities	$ 32,954	$ 44,096

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (129,422)	$ (128,637)	$ (131,289)	$ (142,310)	$ (19,820)	$ (89,445)	$ (389,348)	$ (251,575)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Stockholders' Equity

9 Months Ended

Sep. 30, 2023

Equity [Abstract]

Stockholders' Equity

Note 8 — Stockholders’ Equity

Equity Incentive Plan

Our 2004 Plan provides for us to grant incentive stock options, non-statutory stock options, restricted stock, stock appreciation rights, restricted stock units, performance shares and performance units to employees, directors, and consultants. We may grant options for terms of up to ten years at prices not lower than 100% of the fair market value of our common stock on the date of grant. Options granted to new employees generally vest 25% after one year and monthly thereafter over a period of four years. Options granted to existing employees generally vest monthly over a period of four years.

Our annual grant of stock-based compensation takes place during the first quarter of each year. Our stock options and restricted stock units granted for the first quarter of 2023 was as follows:


	Grants		Weighted Average Grant Date Fair Value per Share
Stock options		1,907,875	$	39.21
Restricted stock units		913,483	$	39.14

As of September 30, 2023, the total authorized shares under the 2004 Plan available for grant was 7.6 million.

Stock-based compensation expense was $18.7 million and $13.2 million for the three months ended September 30, 2023 and 2022, respectively, and $52.6 million and $34.4 million for the nine months ended September 30, 2023 and 2022, respectively.

Controlled Equity Offering Sales Agreement with Cantor Fitzgerald & Co.

On March 1, 2023, we entered into the Amended ATM Facility, with Cantor, under which we may offer and sell, from time to time at our sole discretion, shares of the Common Stock having an aggregate offering price of up to $300.0 million through Cantor, as sales agent. The Amended ATM Facility amends, restates and supersedes the Controlled Equity Offering Sales Agreement dated as of March 6, 2019 between the Company and Cantor.

Cantor may sell the Common Stock by any method that is deemed to be an “at the market offering” as defined in Rule 415 of the Securities Act of 1933, as amended, including sales made directly on the Nasdaq Global Select Market or any other trading market for our common stock. Cantor will use commercially reasonable efforts to sell the Common Stock from time to time, based upon instructions from us (including any price, time or size limits or other customary parameters or conditions we may impose). We will pay Cantor a commission of up to 3.0% of the aggregate gross sales proceeds of any common stock sold through Cantor under the Amended ATM Facility, and also have provided Cantor with customary indemnification rights.

During the three and nine months ended September 30, 2023, we issued 38,431 shares of our common stock for net proceeds of $1.3 million under the Amended ATM Facility.

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Balance Sheet Components - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 99,692	$ 65,582
Restricted cash	375	1,600
Total cash, cash equivalents, and restricted cash as reported within our consolidated statement of cash flows	$ 100,067	$ 67,182

Agreements with Royalty Pharma - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended				9 Months Ended
	Jan. 07, 2022	Mar. 31, 2022	Feb. 28, 2017	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2023	Jul. 01, 2023	Feb. 28, 2023	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Arrangement consideration of debt transaction	$ 150,000
Liabilities				$ 1,179,415			$ 1,122,675	$ 1,179,415
RP Loan Agreement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt				$ 68,583				$ 68,583
2022 Royalty Pharma Transactions [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Milestone payment	50,000
2022 Royalty Pharma Transactions [Member] \| RP Aficamten RPA, RPI ICAV [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Upfront payment	50,000
Purchased rights to certain revenue streams from net sales in consideration payment	$ 50,000
Percentage of net sales payable	4.50%
4.5% of net revenue to be receivable from annual worldwide net sales	$ 1,000,000
Percentage of net sales payable for excess of annual worldwide net sales	3.50%
3.5% of net sales payable for excess of annual worldwide net sales	$ 1,000,000
Imputed rate of interest on unamortized portion of liability				18.00%			22.40%	18.00%
2022 Royalty Pharma Transactions [Member] \| RP Aficamten RPA, RPI ICAV [Member] \| oHCM [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Additional consideration amount paid of first pivotal clinical trail		$ 50,000
2022 Royalty Pharma Transactions [Member] \| RP Aficamten RPA, RPI ICAV [Member] \| nHCM [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Additional consideration amount paid of first pivotal clinical trail								$ 50,000
2022 Royalty Pharma Transactions [Member] \| RP Aficamten RPA, RPI ICAV [Member] \| Maximum [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Purchased rights to certain revenue streams from net sales in consideration payment	$ 150,000
2022 Royalty Pharma Transactions [Member] \| RP Aficamten RPA, RPI ICAV [Member] \| Change in Accounting Estimate [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Imputed rate of interest on unamortized liability				18.00%	19.00%	22.40%	22.40%	18.00%
Non-cash interest expense recognized				$ 5,400	$ 4,900	$ 5,400	$ 5,200
Decrease in non-cash interest expense								$ 1,500
2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Estimated fair value of long term debt				56,500				56,500
Term loan, maturity year	10 years
Debt instrument effective interest rate	7.65%
Applicable prepayment charges on term loan	$ 34,600
Debt Instrument, Face Amount	$ 50,000
2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 1 Tranche 4 and Tranche 5 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Repayable loan percentage to principal amount Including interest and other fees	190.00%
2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 2 and Tranche 3 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Repayable loan percentage to principal amount Including interest and other fees	200.00%
2022 Royalty Pharma Transactions [Member] \| RP Aficamten RPA [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Additional consideration amount paid								50,000
Royalty Purchase Finance Trust Agreement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Liabilities related to revenue participation right purchase agreements, net		$ 183,378		$ 199,251	$ 197,780	$ 196,334	$ 195,384	$ 199,251			$ 191,360	$ 187,835	$ 179,072
Royalty Purchase Finance Trust Agreement [Member] \| RP OM RPA [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Imputed rate of interest on unamortized liability				2.90%			8.50%	2.90%
Non-cash interest expense recognized								$ 92,300
Royalty Purchase Finance Trust Agreement [Member] \| RP OM RPA [Member] \| Maximum [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Increase in royalty rate						5.50%
Royalty Purchase Finance Trust Agreement [Member] \| RP OM RPA [Member] \| Change in Accounting Estimate [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Imputed rate of interest on unamortized liability				0.00%	2.90%	1.90%	8.50%	0.00%
Non-cash interest expense recognized				$ 1,400	$ 1,400	$ 900	$ 4,000
Decrease in non-cash interest expense								$ 8,600
CRL Option [Member] \| 2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Term loan, maximum borrowing capacity	$ 300,000
Term loan, current borrowing capacity	50,000
Term loan, remaining borrowing capacity	250,000
CRL Option [Member] \| 2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 2 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt	50,000
CRL Option [Member] \| 2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 3 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt	25,000
CRL Option [Member] \| 2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 4 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt	75,000
CRL Option [Member] \| 2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 5 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt	$ 100,000
CRL Option [Member] \| 2022 Royalty Pharma Transactions [Member] \| RP Loan Agreement [Member] \| Term Loan Tranche 4 and 5 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Term loan, remaining borrowing capacity										$ 175,000
CRL Option [Member] \| Royalty Purchase Finance Trust Agreement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Cash payment under royalty agreement			$ 90,000
Purchase of common stock shares			875,656
Stock issued during period, value, issued for services			$ 10,000
Liabilities			$ 92,300
Additional percent of royalty on net sale			1.00%
CRL Option [Member] \| Royalty Purchase Finance Trust Agreement [Member] \| Maximum [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Percent of royalty on net sale	5.50%
Increase in royalty rate									5.50%
CRL Option [Member] \| Royalty Purchase Finance Trust Agreement [Member] \| Minimum [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Percent of royalty on net sale			4.50%

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2023	Nov. 01, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Trading Symbol	CYTK
Entity Registrant Name	CYTOKINETICS, INCORPORATED
Entity Central Index Key	0001061983
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	000-50633
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3291317
Entity Address, Address Line One	350 Oyster Point Blvd
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	624-3000
Entity Common Stock, Shares Outstanding		98,053,647
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Agreements with Royalty Pharma (Tables)

9 Months Ended

Sep. 30, 2023

Agreements with Royalty Pharma [Abstract]

Schedule of Initial Consideration

The initial consideration was allocated as follows (in thousands):


	Fair Value		Proceeds		Allocation
Units of Accounting:
Revenue Participation Right Purchase Agreement	$	69,498	$	100,000	$	89,571
Development Funding Loan Agreement		46,887		50,000		60,429
Total consideration	$	116,385	$	150,000	$	150,000

Schedule of Future Minimum Payments under Term Loan Agreement

Future minimum payments under the existing borrowing under RP Loan Agreement are (in thousands):


Years ending December 31:
2023 remainder	$	1,440
2024		10,080
2025		11,520
2026		11,520
2027		11,520
Thereafter		48,960
Future minimum payments		95,040
Less: Unamortized interest and loan costs		(26,457	)
Term Loan, net	$	68,583

Schedule of Activity within Liabilities Related to Sale of Future Royalties

Changes to the RP Aficamten Liability and the RP OM Liability are as follows (in thousands):


	2023				2022
	RP Aficamten Liability		RP OM Liability		RP Aficamten Liability		RP OM Liability
Beginning balance, January 1	$	105,117	$	195,384	$	—	$	179,072
Initial carrying value		—		—		89,571		—
Interest accretion		5,363		917		2,286		4,278
Amortization of issuance costs		—		33		—		28
Ending balance, March 31		110,480		196,334		91,857		183,378
Interest accretion		4,903		1,419		2,574		4,429
Amortization of issuance costs		—		27		—		28
Ending balance, June 30		115,383		197,780		94,431		187,835
Additional consideration		50,000		—		—		—
Interest accretion		5,415		1,445		5,469		3,494
Amortization of issuance costs		—		26		—		31
Ending balance, September 30	$	170,798	$	199,251	$	99,900	$	191,360

Debt - Additional Information (Detail)			3 Months Ended		9 Months Ended
Debt - Additional Information (Detail)	Jul. 06, 2022 USD ($) $ / shares shares	Nov. 13, 2019 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) Days $ / shares shares	Sep. 30, 2022 USD ($)	Dec. 31, 2022 $ / shares
Debt Instrument [Line Items]
Interest expense			$ 7,136,000	$ 6,804,000	$ 21,142,000	$ 12,357,000
Loss on extinguishment of debt						$ (2,693,000)
Common stock, par value \| $ / shares			$ 0.001		$ 0.001		$ 0.001
Conversion of units					$ 404,900,000
2026 Notes [Member]
Debt Instrument [Line Items]
Principal amount of original loan		$ 138,000,000	$ 21,131,000		21,131,000
Issuance of shares of common stock \| shares	8,071,343
Repurchase of principal amount of original loan	$ 116,900,000
Aggregate principal amount remaining			21,100,000		$ 21,100,000
Number of instalments description					payable semi-annually on May 15 and December 15 of each year, beginning May 15, 2020.
Convertible notes, maturity date		Nov. 15, 2026
Convertible debt, fair value			61,100,000		$ 61,100,000
Convertible notes, interest rate		4.00%
Convertible notes, sinking fund		$ 0
Convertible notes, shares issued \| shares		94.7811
Convertible notes, principal amount		$ 1,000
Convertible notes, initial conversion price \| $ / shares		$ 10.55
Convertible notes, type of equity security issued					common stock
Net proceeds from convertible notes, net of debt discount and issuance costs		$ 133,900,000
Convertible notes, conversion description					The 2026 Notes may be converted at the option of the holder under any of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2020 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 127.5% of the last reported sale price of our common stock on November 7, 2019; (2) during the 5 consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of 2026 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on our common stock; (4) if we call the 2026 Notes for redemption; and (5) at any time from, and including, July 15, 2026 until the close of business on the scheduled trading day immediately before the maturity date, November 15, 2026. We will settle conversions by paying or delivering, as applicable, cash, shares of our common stock, or a combination of cash and shares of our common stock, at our election, based on the applicable conversion rate. The 2026 Notes are convertible at September 30, 2023 based on circumstance (1) defined above.
Convertible notes, redemption description					The 2026 Notes will be redeemable, in whole or in part, at our option at any time, and from time to time, on or after November 20, 2023 and, in the case of any partial redemption, on or before the 60th scheduled trading day before the maturity date, at a cash redemption price equal to the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date but only if the last reported sale price per share of our common stock exceeds 130% of the conversion price on (1) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date we may send the related redemption notice; and (2) the trading day immediately before the date we may send such notice. If a “fundamental change” (as defined in the indenture agreement, dated November 13, 2019 between us and U.S. Bank National Association, as trustee, as supplemented by the first supplemental indenture dated as of November 13, 2019 between us and such trustee) occurs, then, subject to certain exceptions, holders may require us to repurchase their 2026 Notes at a cash repurchase price equal to the principal amount of the 2026 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date.
Debt instrument, unamortized debt issuance cost			$ 400,000		$ 400,000
Unamortized debt discount amortization period			3 years 2 months 12 days		3 years 2 months 12 days
Conversion of units \| shares					2,600,000
Conversion of units					$ 75,200,000
Stock price \| $ / shares			$ 29.46		$ 29.46
If-converted value in excess of principal amount					$ 54,100,000
2026 Notes [Member] \| Liability [Member]
Debt Instrument [Line Items]
Debt instrument effective interest rate			4.60%		4.60%
2026 Notes [Member] \| Debt Instrument Convertible Covenant One [Member]
Debt Instrument [Line Items]
Convertible notes, percentage of conversion price					127.50%
Convertible notes, trading days \| Days					20
Convertible notes, consecutive trading days \| Days					30
2026 Notes [Member] \| Debt Instrument Convertible Covenant Two [Member]
Debt Instrument [Line Items]
Convertible notes, percentage of last reported sale price of common stock					98.00%
Convertible notes, trading days \| Days					5
Convertible notes, consecutive trading days \| Days					10
2027 Notes [Member]
Debt Instrument [Line Items]
Principal amount of original loan	540,000,000		$ 540,000,000		$ 540,000,000
Payment associated with convertible notes	$ 140,300,000
Number of instalments description	payable semiannually in arrears on January 1 and July 1 of each year, beginning on January 1, 2023.
Convertible notes, maturity date	Jul. 01, 2027
Convertible debt, fair value			464,900,000		464,900,000
Convertible notes, interest rate	3.50%
Convertible notes, shares issued \| shares	19.5783
Convertible notes, principal amount	$ 1,000				$ 1,000
Convertible notes, initial conversion price \| $ / shares	$ 51.08
Convertible notes, type of equity security issued					common stock
Net proceeds from convertible notes, net of debt discount and issuance costs	$ 523,600,000
Convertible notes, conversion description					The 2027 Notes are convertible into cash, shares of our common stock or a combination of cash and shares of our common stock, at our election, based on the applicable conversion rate(s). The initial conversion rate for the 2027 Notes is 19.5783 shares of our common stock per $1,000 principal amount of such Notes, which is equivalent to an initial conversion price of approximately $51.08 per share. Holders of the 2027 Notes may convert all or any portion of their convertible notes at their option only in the following circumstances: (i) during any calendar quarter (and only during such calendar quarter) commencing after the calendar quarter ending on September 30, 2022, if the last reported sale price per share of our common stock, $0.001 par value per share, exceeds 130% of the conversion price for each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (ii) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of 2027 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day; (iii) upon the occurrence of certain corporate events or distributions on our common stock, as described in the 2027 Indenture; (iv) if we call such 2027 Notes for redemption; and (v) at any time from, and including, March 1, 2027 until the close of business on the scheduled trading day immediately before the maturity date.
Convertible notes, redemption description					We may not redeem the 2027 Notes at our option at any time before July 7, 2025. The 2027 Notes will be redeemable, in whole or in part (subject to the “Partial Redemption Limitation” (as defined in the 2027 Indenture)), at our option at any time, and from time to time, on or after July 7, 2025 and, in the case of a partial redemption, on or before the 60th scheduled trading day immediately before the maturity date, at a cash redemption price equal to the principal amount of the 2027 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of our common stock exceeds 130% of the conversion price on (i) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date we may send the related redemption notice; and (ii) the trading day immediately before the date we may send such notice. In addition, calling any of the 2027 Notes for redemption will constitute a Make-Whole Fundamental Change with respect to that convertible note, in which case the conversion rate applicable to the conversion of that Note will be increased in certain circumstances if it is converted after it is called for redemption. The conversion rate for the 2027 Notes shall not exceed 25.4517 shares per $1,000 principal amount of such Notes, subject to certain customary anti-dilution adjustments (as defined in the 2027 indenture). Pursuant to the Partial Redemption Limitation, we may not elect to redeem less than all of the outstanding 2027 Notes unless at least $75.0 million aggregate principal amount of 2027 Notes are outstanding and not subject to redemption as of the time we may send the related redemption notice.
Debt instrument, unamortized debt issuance cost			$ 12,600,000		$ 12,600,000
Unamortized debt discount amortization period			3 years 9 months 18 days		3 years 9 months 18 days
Conversion of units \| shares					13,700,000
Stock price \| $ / shares			$ 29.46		$ 29.46
If-converted value in excess of principal amount					$ 540,000,000
2027 Notes [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Convertible notes, shares issued \| shares	25.4517
2027 Notes [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Aggregate principal amount of notes outstanding	$ 75,000,000
2027 Notes [Member] \| Liability [Member]
Debt Instrument [Line Items]
Debt instrument effective interest rate			4.20%		4.20%
2027 Notes [Member] \| Debt Instrument Convertible Covenant One [Member]
Debt Instrument [Line Items]
Common stock, par value \| $ / shares			$ 0.001		$ 0.001
Convertible notes, percentage of conversion price					130.00%
Convertible notes, trading days \| Days					20
Convertible notes, consecutive trading days \| Days					30
2027 Notes [Member] \| Debt Instrument Convertible Covenant Two [Member]
Debt Instrument [Line Items]
Convertible notes, percentage of last reported sale price of common stock					98.00%
Convertible notes, trading days \| Days					5
Convertible notes, consecutive trading days \| Days					10

Commitments and Contingencies

9 Months Ended

Sep. 30, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 9 — Commitments and Contingencies

Operating Leases

In July 2019, we entered into the Oyster Point Lease of office and laboratory space at a facility located in South San Francisco, California, and we entered into amendments to the Oyster Point Lease in 2020, 2021, and 2022. The Oyster Point Lease commenced on March 31, 2021 and upon commencement, we recognized a right-of-use asset of $77.9 million, a short-term lease liability of $3.7 million and a long-term lease liability of $85.3 million. The long-term lease liability includes $11.1 million of tenant improvement reimbursements as of March 31, 2021. The Oyster Point Lease has an expiration date of October 31, 2033.

As of September 30, 2023, the remaining lease term of the Oyster Point Lease is 10.1 years and the discount rate used to determine the related lease liability was 8.7%. As of September 30, 2023, the total commitment of undiscounted lease payments for the Oyster Point Lease was $211.5 million.

In January 2022, we entered into a series of lease agreements with the sub-landlord and landlord and leased an office space at a facility located in Radnor, Pennsylvania (the "Radnor Lease"). The Radnor Lease commenced on September 1, 2022, when the leasehold improvements were substantially completed, and we gained control over the use of the underlying assets. Upon commencement, we recognized a right-of-use asset of $3.4 million, a short-term lease liability of $0.4 million and a long-term lease liability of $1.9 million. The right-of-use asset includes $1.1 million of lease prepayments made before the commencement date. The Radnor Lease has an expiration date of July 31, 2027.

As of September 30, 2023, the remaining lease term of the Radnor Lease was 3.8 years and the discount rate used to determine the related lease liability was 8.3%. The total commitment of undiscounted lease payments for the Radnor Lease was $2.4 million as of September 30, 2023.

Organization and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Cytokinetics, Incorporated was incorporated under the laws of the state of Delaware on August 5, 1997. The Company is a late-stage biopharmaceutical company focused on the discovery and development of novel small molecule therapeutics that modulate muscle function for the potential treatment of serious diseases and medical conditions. Our financial statements contemplate the conduct of our operations in the normal course of business. We have incurred an accumulated deficit of approximately $2.0 billion since inception and there can be no assurance that we will attain profitability. We had a net loss of $389.3 million and net cash used in operations of $340.3 million for the nine months ended September 30, 2023. Cash, cash equivalents, and investments decreased to $554.7 million as of September 30, 2023 from $829.3 million as of December 31, 2022. We anticipate that we will have operating losses and net cash outflows in future periods. We are subject to risks common to late-stage biopharmaceutical companies including, but not limited to, development of new drug candidates, dependence on key personnel, and the ability to obtain additional capital as needed to fund our future plans. Our liquidity will be impaired if sufficient additional capital is not available on terms acceptable to us. To date, we have funded operations primarily through sales of our common stock, contract payments under our collaboration agreements, sales of future revenues and royalties, debt financing arrangements, government grants and interest income. Until we achieve profitable operations, we intend to continue to fund operations through payments from strategic collaborations, additional sales of equity securities, grants and debt financings. We have never generated revenues from commercial sales of our drugs and may not have drugs to market for at least several years, if ever. Our success is dependent on our ability to enter into new strategic collaborations and/or raise additional capital and to successfully develop and market one or more of our drug candidates. We cannot be certain that sufficient funds will be available from such a financing or through a collaborator when required or on satisfactory terms. Additionally, there can be no assurance that our drug candidates will be accepted in the marketplace or that any future products can be developed or manufactured at an acceptable cost. These factors could have a material adverse effect on our future financial results, financial position and cash flows. Based on the current status of our research and development activities, we believe that our existing cash, cash equivalents and investments will be sufficient to fund cash requirements for at least the next 12 months after the issuance of this Quarterly Report on Form 10-Q. If, at any time, our prospects for financing our research and development programs decline, we may decide to reduce research and development expenses by delaying, discontinuing or reducing our funding of one or more of our research or development programs. Alternatively, we might raise funds through strategic collaborations, public or private financings or other arrangements. Such funding, if needed, may not be available on favorable terms, or at all. The financial statements do not include any adjustments that might result from the outcome of this uncertainty.
Basis of Presentation	Basis of Presentation Our condensed consolidated financial statements include the accounts of Cytokinetics and our wholly-owned subsidiaries. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. The financial statements include all adjustments (consisting only of normal recurring adjustments) that management believes are necessary for the fair statement of our financial information. These interim results are not necessarily indicative of results to be expected for the full fiscal year or any future interim period. The balance sheet as of December 31, 2022 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by GAAP for complete financial statements. The financial statements and related disclosures have been prepared with the presumption that users of the interim financial statements have read or have access to the audited financial statements for the preceding fiscal year. Accordingly, these financial statements should be read in conjunction with the audited financial statements and notes thereto contained in the Company’s Form 10-K for the year ended December 31, 2022, as filed with the Securities and Exchange Commission.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. We evaluate our estimates on an ongoing basis. We base our estimates on our historical experience and also on assumptions that we believe are reasonable; however, actual results could significantly differ from those estimates.

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents [Abstract]
Restricted cash	$ 375	$ 1,600

Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2023

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options and Restricted Stock Units Granted

Our annual grant of stock-based compensation takes place during the first quarter of each year. Our stock options and restricted stock units granted for the first quarter of 2023 was as follows:


	Grants		Weighted Average Grant Date Fair Value per Share
Stock options		1,907,875	$	39.21
Restricted stock units		913,483	$	39.14

Organization and Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit incurred	$ (1,975,342)						$ (1,975,342)		$ (1,585,994)
Cash requirements term							12 months
Net Income (Loss)	(129,422)	$ (128,637)	$ (131,289)	$ (142,310)	$ (19,820)	$ (89,445)	$ (389,348)	$ (251,575)
Cash, cash equivalents and investments	$ 554,700						554,700		$ 829,300
Net cash provided by (used in) operating activities							$ 340,296	$ 201,326

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Debt

9 Months Ended

Sep. 30, 2023

Debt Disclosure [Abstract]

Debt

Note 7 — Debt

Convertible Notes

On November 13, 2019, we issued $138.0 million aggregate principal amount of 2026 Notes. On July 6, 2022, we issued $540.0 million aggregate principal amount of 2027 Notes and used approximately $140.3 million of the net proceeds from the offering of 2027 Notes and issued 8,071,343 shares of common stock to repurchase approximately $116.9 million aggregate principal amount of the 2026 Notes pursuant to privately negotiated exchange agreements entered into with certain holders of the 2026 Notes concurrently with the pricing of the offering of the 2027 Notes. As of September 30, 2023, there remain $21.1 million aggregate principal amount of 2026 Notes outstanding.

The 2026 Notes are unsecured obligations and bear interest at an annual rate of 4.0% per year, payable semi-annually on May 15 and December 15 of each year, beginning May 15, 2020. The 2026 Notes are governed by an indenture we entered into with U.S. Bank National Association, as trustee. The 2026 Notes will mature on November 15, 2026, unless earlier repurchased or redeemed by us or converted at the option of the holders. We may redeem the 2026 Notes prior to the maturity date but is not required to and no sinking fund is provided for the 2026 Notes. The 2026 Notes may be converted, under certain circumstances as described below, based on an initial conversion rate of 94.7811 shares of common stock per $1,000 principal amount (which represents an initial conversion price of $10.55 per share). The conversion rate for the 2026 Notes will be subject to adjustment upon the occurrence of certain specified events. In addition, upon the occurrence of a make-whole fundamental change (as defined in the indenture), we will, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert its notes in connection with such make-whole fundamental change. We received approximately $133.9 million in net proceeds, after deducting the initial purchasers’ discount, from the issuance of the 2026 Notes.

The 2026 Notes may be converted at the option of the holder under any of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2020 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 127.5% of the last reported sale price of our common stock on November 7, 2019; (2) during the 5 consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of 2026 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on our common stock; (4) if we call the 2026 Notes for redemption; and (5) at any time from, and including, July 15, 2026 until the close of business on the scheduled trading day immediately before the maturity date, November 15, 2026. We will settle conversions by paying or delivering, as applicable, cash, shares of our common stock, or a combination of cash and shares of our common stock, at our election, based on the applicable conversion rate. The 2026 Notes are convertible at September 30, 2023 based on circumstance (1) defined above.

The 2026 Notes will be redeemable, in whole or in part, at our option at any time, and from time to time, on or after November 20, 2023 and, in the case of any partial redemption, on or before the 60th scheduled trading day before the maturity date, at a cash redemption price equal to the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date but only if the last reported sale price per share of our common stock exceeds 130% of the conversion price on (1) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date we may send the related redemption notice; and (2) the trading day immediately before the date we may send such notice. If a “fundamental change” (as defined in the indenture agreement, dated November 13, 2019 between us and U.S. Bank National Association, as trustee, as supplemented by the first supplemental indenture dated as of November 13, 2019 between us and such trustee) occurs, then, subject to certain exceptions, holders may require us to repurchase their 2026 Notes at a cash repurchase price equal to the principal amount of the 2026 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date.

The following table presents the total amount of interest cost recognized relating to the 2026 Notes (in thousands):


	Three Months Ended September 30, 2023		Three Months Ended September 30, 2022		Nine Months Ended September 30, 2023		Nine Months Ended September 30, 2022
Contractual interest expense	$	211	$	294	$	633	$	3,054
Amortization of debt issuance costs		29		19		79		328
Total interest expense recognized	$	240	$	313	$	712	$	3,382

The effective interest rate of the 2026 Notes was 4.6% for the nine months ended September 30, 2023. As of September 30, 2023, the unamortized debt issuance cost for the 2026 Notes was $0.4 million and will be amortized over approximately 3.2 years. If the 2026 Notes were to be converted on September 30, 2023, the holders of the 2026 Notes would receive common shares of 2.6 million with an aggregate value of $75.2 million based on the Company’s closing stock price of $29.46 as of September 30, 2023. The if-converted value of the 2026 Notes exceeded its principal amount by $54.1 million as of September 30, 2023.

The 2027 Notes ($540.0 million of aggregate principal) are our senior, unsecured obligations and are (i) senior in right of payment to our future indebtedness that is expressly subordinated to the 2027 Notes in right of payment; (ii) equal in right of payment with all of our indebtedness that is not so subordinated (including the 2026 Notes); (iii) effectively subordinated to our existing and future secured indebtedness, to the extent of the value of the collateral securing that indebtedness; and (iv) structurally subordinated to all existing and future indebtedness and other liabilities, including trade payables, and (to the extent we are not a holder thereof) preferred equity, if any, of our subsidiaries. The net proceeds of the 2027 Notes were approximately $523.6 million after deducting issuance costs related to the 2027 Notes. The 2027 Notes bear interest at a rate of 3.5% per year, payable semiannually in arrears on January 1 and July 1 of each year, beginning on January 1, 2023. The 2027 Notes will mature on July 1, 2027, unless earlier converted, redeemed or repurchased.

The 2027 Notes are convertible into cash, shares of our common stock or a combination of cash and shares of our common stock, at our election, based on the applicable conversion rate(s). The initial conversion rate for the 2027 Notes is 19.5783 shares of our common stock per $1,000 principal amount of such Notes, which is equivalent to an initial conversion price of approximately $51.08 per share. Holders of the 2027 Notes may convert all or any portion of their convertible notes at their option only in the following circumstances: (i) during any calendar quarter (and only during such calendar quarter) commencing after the calendar quarter ending on September 30, 2022, if the last reported sale price per share of our common stock, $0.001 par value per share, exceeds 130% of the conversion price for each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (ii) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of 2027 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day; (iii) upon the occurrence of certain corporate events or distributions on our common stock, as described in the 2027 Indenture; (iv) if we call such 2027 Notes for redemption; and (v) at any time from, and including, March 1, 2027 until the close of business on the scheduled trading day immediately before the maturity date.

We may not redeem the 2027 Notes at our option at any time before July 7, 2025. The 2027 Notes will be redeemable, in whole or in part (subject to the “Partial Redemption Limitation” (as defined in the 2027 Indenture)), at our option at any time, and from time to time, on or after July 7, 2025 and, in the case of a partial redemption, on or before the 60th scheduled trading day immediately before the maturity date, at a cash redemption price equal to the principal amount of the 2027 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of our common stock exceeds 130% of the conversion price on (i) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date we may send the related redemption notice; and (ii) the trading day immediately before the date we may send such notice. In addition, calling any of the 2027 Notes for redemption will constitute a Make-Whole Fundamental Change with respect to that convertible note, in which case the conversion rate applicable to the conversion of that Note will be increased in certain circumstances if it is converted after it is called for redemption. The conversion rate for the 2027 Notes shall not exceed 25.4517 shares per $1,000 principal amount of such Notes, subject to certain customary anti-dilution adjustments (as defined in the 2027 indenture). Pursuant to the Partial Redemption Limitation, we may not elect to redeem less than all of the outstanding 2027 Notes unless at least $75.0 million aggregate principal amount of 2027 Notes are outstanding and not subject to redemption as of the time we may send the related redemption notice.

If a “Fundamental Change” (as defined in the 2027 Indenture) occurs, then, subject to a limited exception for certain cash mergers, noteholders may require us to repurchase their 2027 Notes at a cash repurchase price equal to the principal amount of the 2027 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. The definition of Fundamental Change includes certain business combination transactions involving us and certain de-listing events with respect to our common stock.

The following table presents the total amount of interest cost recognized relating to the 2027 Notes (in thousands):


	Three Months Ended				Nine Months Ended
	September 30, 2023		September 30, 2022		September 30, 2023		September 30, 2022
Contractual interest expense	$	4,726	$	4,462	$	14,175	$	4,462
Amortization of debt issuance costs		817		749		2,248		749
Total interest expense recognized	$	5,543	$	5,211	$	16,423	$	5,211

The effective interest rate of the 2027 Notes was 4.2% as of September 30, 2023. As of September 30, 2023, the unamortized debt issuance cost for the 2027 Notes was $12.6 million and will be amortized over approximately 3.8 years. If the 2027 Notes were to be converted on September 30, 2023, the holders of the 2027 Notes would receive common shares of 13.7 million with an aggregate value of $404.9 million based on our closing stock price of $29.46 as of September 30, 2023. The if-converted value of the 2027 Notes was below the principal value of the Notes of $540.0 million as of September 30, 2023. In addition, during the nine months ended September 30, 2023, the conditions allowing holders of the Notes to convert were not met. As a result, the 2027 Notes are not convertible during the nine months ended September 30, 2023.

Future minimum payments under the 2027 Notes and 2026 Notes are (in thousands):


Years ending December 31:	2027 Notes			2026 Notes
2023 remainder	$	—		$	423
2024		18,900			845
2025		18,900			845
2026		18,900			21,978
2027		558,900			—
Future minimum payments		615,600			24,091
Less: Interest		(75,600	)		(2,960	)
Convertible notes, principal amount		540,000			21,131
Less: Debt issuance costs on the convertible notes		(12,624	)		(373	)
Net carrying amount of the convertible notes	$	527,376		$	20,758

As of September 30, 2023, the estimated fair value of the 2027 Notes and 2026 Notes was $464.9 million and $61.1 million, respectively, and was based upon observable, Level 2 inputs, including pricing information from recent trades of the convertible notes.

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Insider Trading Arrangements	9 Months Ended
Insider Trading Arrangements	Sep. 30, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	• John T. Henderson, M.D., Ch.B., Chairman of our Board of Directors - Dr. Henderson entered into a Rule 10b5-1 trading arrangement on September 18, 2023 that was intended to satisfy the affirmative defense of Rule 10b5-1(c) (the “Henderson 2023 Plan”). In accordance with its terms, the Henderson 2023 Plan includes the exercise of up to 18,020 stock options to acquire shares of our common stock and the subsequent sale of all shares of common stock acquired upon such exercise of stock options at various limit prices at pre-specified dates during the term of the plan. The Henderson 2023 Plan will terminate on the earlier of (x) May 25, 2024 and (y) the sale of all shares of common stock that are subject to such plan. • Wendell Wierenga, Ph.D., Member of our Board of Directors - Dr. Wierenga entered into a Rule 10b5-1 trading arrangement on September 7, 2023 that was intended to satisfy the affirmative defense of Rule 10b5-1(c) (the “Wierenga 2023 Plan”). In accordance with its terms, the Wierenga 2023 Plan includes the exercise of up to 10,000 stock options to acquire shares of our common stock and the subsequent sale of all shares of common stock acquired upon such exercise of stock options at various limit prices at pre-specified dates during the term of the plan. The Wierenga 2023 Plan will terminate on the earlier of (x) May 21, 2024 and (y) the sale of all shares of common stock that are subject to such plan. • Fady I. Malik, M.D., Ph.D., Executive Vice President, Research and Development - Dr. Malik entered into a Rule 10b5-1 trading arrangement on September 26, 2023 that was intended to satisfy the affirmative defense of Rule 10b5-1(c) (the “Malik 2023 Plan”). In accordance with its terms, the Malik 2023 Plan includes the exercise of up to 111,678 stock options to acquire shares of our common stock and the subsequent sale of all shares of common stock acquired upon such exercise of stock options at various limit prices at pre-specified dates during the term of the plan. The Malik 2023 Plan also includes the sale of up to 17,361 shares of common stock at the market price on the scheduled date of such sales at pre-specified dates during the term of the plan. The Malik 2023 Plan will terminate on the earlier of (x) May 8, 2024 and (y) the sale of all shares of common stock that are subject to such plan. Certain of our officers have made elections to participate in, and are participating in, our employee stock purchase plan, which may be designed to satisfy the affirmative defense conditions of Rule 10b5-1 under the Exchange Act or may constitute non-Rule 10b5–1 trading arrangements. In addition, certain of our directors have made elections to participate in, and are participating in, our director equity in lieu of cash retainer option program (as described in the “Director Compensation” section of our Proxy Statement for our 2023 Annual Meeting), which may be designed to satisfy the affirmative defense conditions of Rule 10b5-1 under the Exchange Act or may constitute non-Rule 10b5–1 trading arrangements.
John T. Henderson [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	true
Rule 10b5-1 Arrangement Terminated	false
Wendell Wierenga [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	true
Rule 10b5-1 Arrangement Terminated	false
Fady I. Malik [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	true
Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Trading Plan [Member] \| John T. Henderson [Member]
Trading Arrangements, by Individual
Name	John T. Henderson
Title	Chairman of our Board of Directors
Adoption Date	September 18, 2023
Termination Date	May 25, 2024
Rule 10b5-1 Trading Plan [Member] \| Wendell Wierenga [Member]
Trading Arrangements, by Individual
Name	Wendell Wierenga
Title	Member of our Board of Directors
Adoption Date	September 7, 2023
Termination Date	May 21, 2024
Rule 10b5-1 Trading Plan [Member] \| Fady I. Malik [Member]
Trading Arrangements, by Individual
Name	Fady I. Malik
Title	Vice President, Research and Development
Adoption Date	September 26, 2023
Termination Date	May 8, 2024
Rule 10B51Trading Plan One [Member] \| John T. Henderson [Member]
Trading Arrangements, by Individual
Aggregate Available	18,020
Rule 10B51Trading Plan Two [Member] \| Wendell Wierenga [Member]
Trading Arrangements, by Individual
Aggregate Available	10,000
Rule 10B51Trading Plan Three [Member] \| Fady I. Malik [Member]
Trading Arrangements, by Individual
Aggregate Available	111,678
Rule 10B51Trading Plan Four [Member] \| Fady I. Malik [Member]
Trading Arrangements, by Individual
Aggregate Available	17,361

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands			9 Months Ended
	Sep. 01, 2022	Mar. 31, 2021	Sep. 30, 2023	Dec. 31, 2022	Aug. 31, 2022	Feb. 28, 2021
Lessee Lease Description [Line Items]
Operating lease, right-of-use assets			$ 79,929	$ 82,737
Operating lease, short-term lease liability			17,236	12,829
Operating lease, long-term lease liability			$ 122,216	$ 126,895
Oyster Point Lease [Member] \| California [Member]
Lessee Lease Description [Line Items]
Operating lease, lease expiration date			Oct. 31, 2033
Operating lease, commencement date		Mar. 31, 2021
Operating lease, right-of-use assets		$ 77,900
Operating lease, short-term lease liability		3,700
Operating lease, long-term lease liability		$ 85,300
Operating lease, tenant improvement reimbursements						$ 11,100
Operating lease, weighted average remaining lease term			10 years 1 month 6 days
Operating lease, weighted average discount rate			8.70%
Operating lease undiscounted lease payments			$ 211,500
Radnor Lease [Member] \| Pennsylvania [Member]
Lessee Lease Description [Line Items]
Operating lease, lease expiration date			Jul. 31, 2027
Operating lease, commencement date	Sep. 01, 2022
Operating lease, right-of-use assets	$ 3,400
Operating lease, short-term lease liability	400
Operating lease, long-term lease liability	$ 1,900
Operating lease, weighted average remaining lease term			3 years 9 months 18 days
Operating lease, weighted average discount rate			8.30%
Operating lease undiscounted lease payments			$ 2,400
Right-of-use asset, prepayment					$ 1,100

Debt - Schedule of Future Minimum Payments under 2026 Notes and 2027 Notes (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Jul. 06, 2022	Nov. 13, 2019
Debt Instrument [Line Items]
Net carrying amount of the convertible notes	$ 548,134	$ 545,808
2026 Notes [Member]
Debt Instrument [Line Items]
2023 remainder	423
2024	845
2025	845
2026	21,978
2027	0
Future minimum payments	24,091
Less: Interest	(2,960)
Convertible notes, principal amount	21,131			$ 138,000
Less: Debt issuance costs on the convertible notes	(373)
Net carrying amount of the convertible notes	20,758
2027 Notes [Member]
Debt Instrument [Line Items]
2023 remainder	0
2024	18,900
2025	18,900
2026	18,900
2027	558,900
Future minimum payments	615,600
Less: Interest	(75,600)
Convertible notes, principal amount	540,000		$ 540,000
Less: Debt issuance costs on the convertible notes	(12,624)
Net carrying amount of the convertible notes	$ 527,376

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 99,692	$ 65,582
Short-term investments	439,547	716,995
Accounts receivable	2,499	147
Prepaid expenses and other current assets	19,678	12,462
Total current assets	561,416	795,186
Long-term investments	15,468	46,708
Property and equipment, net	75,614	80,453
Operating lease right-of-use assets	79,929	82,737
Other assets	8,187	9,691
Total assets	740,614	1,014,775
Current liabilities:
Accounts payable	13,796	25,611
Accrued liabilities	32,954	44,096
Short-term operating lease liabilities	17,236	12,829
Other current liabilities	13,737	2,081
Total current liabilities	77,723	84,617
Term loan, net	60,885	63,810
Convertible notes, net	548,134	545,808
Liabilities related to revenue participation right purchase agreement, net	370,049	300,501
Long-term operating lease liabilities	122,216	126,895
Other non-current liabilities	408	1,044
Total liabilities	1,179,415	1,122,675
Commitments and contingencies
Stockholders' deficit:
Preferred stock, $0.001 par value	0	0
Common stock, $0.001 par value	94	94
Additional paid-in capital	1,537,321	1,481,590
Accumulated other comprehensive loss	(874)	(3,590)
Accumulated deficit	(1,975,342)	(1,585,994)
Total stockholders' deficit	(438,801)	(107,900)
Total liabilities and stockholders' deficit	$ 740,614	$ 1,014,775

Stockholders' Equity - Summary of Stock Options and Restricted Stock Units Granted (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Stock options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock options, Grants \| shares	1,907,875
Stock options, Weighted average date fair value per share \| $ / shares	$ 39.21
Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock units, Grants \| shares	913,483
Restricted stock units, Weighted average date fair value per share \| $ / shares	$ 39.14

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
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-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
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-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
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-Subparagraph (c)(2)(iii)(02)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 21: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
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-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2023

Fair Value Disclosures [Abstract]

Summary of Fair Value of Financial Assets Consists of Cash Equivalents and Investments Classified as Available-for-sale Securities Measured on Recurring Basis


		September 30, 2023
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	56,714	$	—	$	—		$	56,714
U.S. Treasury securities	Level 1		55,029		3		(42	)		54,990
U.S. Government agency securities	Level 2		167,184		45		(309	)		166,920
Commercial paper	Level 2		219,468		4		(209	)		219,263
Corporate obligations	Level 2		52,825		—		(366	)		52,459
		$	551,220	$	52	$	(926	)	$	550,346


		December 31, 2022
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	45,887	$	—	$	—		$	45,887
U.S. Treasury securities	Level 1		172,568		—		(1,102	)		171,466
U.S. Treasury securities backed repurchase agreements	Level 2		16,003		—		—			16,003
U.S. Government agency securities	Level 2		129,174		12		(820	)		128,366
Foreign government agency securities	Level 2		7,599		—		(69	)		7,530
Commercial paper	Level 2		329,359		28		(431	)		328,956
Corporate obligations	Level 2		128,594		—		(1,209	)		127,385
		$	829,184	$	40	$	(3,631	)	$	825,593

Condensed Consolidated Statements of Stockholders' (Deficit) Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2021	$ 243,863	$ 84	$ 1,452,268	$ (869)	$ (1,207,620)
Beginning Balance (ASU 2020-06) at Dec. 31, 2021	(38,895)	$ 0	(49,476)	0	10,581
Beginning Balance, shares at Dec. 31, 2021		84,799,542
Beginning Balance, shares (ASU 2020-06) at Dec. 31, 2021		0
Exercise of stock options, value	4,075	$ 1	4,074	0	0
Exercise of stock options, shares		374,242
Vesting of restricted stock units, value	0	$ 0	0	0	0
Vesting of restricted stock units, shares		663,341
Shares withheld related to net share settlement of equity awards, value	(9,602)	$ 0	(9,602)	0	0
Shares withheld related to net share settlement of equity awards, shares		(260,172)
Stock-based compensation	8,985		8,985	0	0
Other comprehensive income (loss)	(2,720)	$ 0	0	(2,720)	0
Net Income (Loss)	(89,445)	0	0	0	(89,445)
Ending Balance at Mar. 31, 2022	116,261	$ 85	1,406,249	(3,589)	(1,286,484)
Ending Balance, shares at Mar. 31, 2022		85,576,953
Beginning Balance at Dec. 31, 2021	243,863	$ 84	1,452,268	(869)	(1,207,620)
Beginning Balance (ASU 2020-06) at Dec. 31, 2021	(38,895)	$ 0	(49,476)	0	10,581
Beginning Balance, shares at Dec. 31, 2021		84,799,542
Beginning Balance, shares (ASU 2020-06) at Dec. 31, 2021		0
Net Income (Loss)	(251,575)
Ending Balance at Sep. 30, 2022	(15,977)	$ 93	1,438,103	(5,559)	(1,448,614)
Ending Balance, shares at Sep. 30, 2022		94,578,052
Beginning Balance at Mar. 31, 2022	116,261	$ 85	1,406,249	(3,589)	(1,286,484)
Beginning Balance, shares at Mar. 31, 2022		85,576,953
Exercise of stock options, value	2,143	$ 0	2,143
Exercise of stock options, shares		233,365
Vesting of restricted stock units, value	0	$ 0	0	0	0
Vesting of restricted stock units, shares		41,628
Issuance of common stock under Employee Stock Purchase Plan, value	1,540	$ 0	1,540	0	0
Issuance of common stock under Employee Stock Purchase Plan, shares		49,088
Exercise of warrants, value	0	$ 0	0	0	0
Exercise of warrants, share		14,136
Stock-based compensation	12,195	$ 0	12,195	0	0
Other comprehensive income (loss)	(905)	0	0	(905)	0
Net Income (Loss)	(19,820)	0	0	0	(19,820)
Ending Balance at Jun. 30, 2022	111,414	$ 85	1,422,127	(4,494)	(1,306,304)
Ending Balance, shares at Jun. 30, 2022		85,915,170
Exercise of stock options, value	6,187	$ 0	6,187	0	0
Exercise of stock options, shares		577,369
Induced conversion of convertible notes	(3,378)	$ 8	(3,386)	0	0
Induced conversion of convertible notes, shares		8,071,343
Exercise of warrants, value	0	$ 0	0	0	0
Exercise of warrants, share		14,170
Stock-based compensation	13,175	$ 0	13,175	0	0
Other comprehensive income (loss)	(1,065)	0	0	(1,065)	0
Net Income (Loss)	(142,310)	0	0	0	(142,310)
Ending Balance at Sep. 30, 2022	(15,977)	$ 93	1,438,103	(5,559)	(1,448,614)
Ending Balance, shares at Sep. 30, 2022		94,578,052
Beginning Balance at Dec. 31, 2022	(107,900)	$ 94	1,481,590	(3,590)	(1,585,994)
Beginning Balance, shares at Dec. 31, 2022		94,833,975
Exercise of stock options, value	3,547	$ 0	3,547	0	0
Exercise of stock options, shares		369,298
Vesting of restricted stock units, value	0	$ 0	0	0	0
Vesting of restricted stock units, shares		668,835
Shares withheld related to net share settlement of equity awards, value	(10,517)	$ 0	(10,517)	0	0
Shares withheld related to net share settlement of equity awards, shares		(262,829)
Stock-based compensation	15,194	$ 0	15,194	0	0
Other comprehensive income (loss)	1,945	0	0	1,945	0
Net Income (Loss)	(131,289)	0	0	0	(131,289)
Ending Balance at Mar. 31, 2023	(229,020)	$ 94	1,489,814	(1,645)	(1,717,283)
Ending Balance, shares at Mar. 31, 2023		95,609,279
Beginning Balance at Dec. 31, 2022	(107,900)	$ 94	1,481,590	(3,590)	(1,585,994)
Beginning Balance, shares at Dec. 31, 2022		94,833,975
Net Income (Loss)	(389,348)
Ending Balance at Sep. 30, 2023	(438,801)	$ 94	1,537,321	(874)	(1,975,342)
Ending Balance, shares at Sep. 30, 2023		96,251,844
Beginning Balance at Mar. 31, 2023	(229,020)	$ 94	1,489,814	(1,645)	(1,717,283)
Beginning Balance, shares at Mar. 31, 2023		95,609,279
Exercise of stock options, value	3,286	$ 0	3,286	0	0
Exercise of stock options, shares		206,605
Vesting of restricted stock units, value	0	$ 0	0	0	0
Vesting of restricted stock units, shares		46,989
Issuance of common stock under Employee Stock Purchase Plan, value	2,401	$ 0	2,401	0	0
Issuance of common stock under Employee Stock Purchase Plan, shares		74,937
Stock-based compensation	18,668	$ 0	18,668	0	0
Other comprehensive income (loss)	187	0	0	187	0
Net Income (Loss)	(128,637)	0	0	0	(128,637)
Ending Balance at Jun. 30, 2023	(333,115)	$ 94	1,514,169	(1,458)	(1,845,920)
Ending Balance, shares at Jun. 30, 2023		95,937,810
Exercise of stock options, value	3,124	$ 0	3,124	0	0
Exercise of stock options, shares		273,149
Vesting of restricted stock units, value	0	$ 0	0	0	0
Vesting of restricted stock units, shares		2,454
Issuance of common stock under at-the-market offering, net of issuance costs, value	1,312	$ 0	1,312	0	0
Issuance of common stock under at-the-market offering, net of issuance costs, shares		38,431
Stock-based compensation	18,716	$ 0	18,716	0	0
Other comprehensive income (loss)	584	0	0	584	0
Net Income (Loss)	(129,422)	0	0	0	(129,422)
Ending Balance at Sep. 30, 2023	$ (438,801)	$ 94	$ 1,537,321	$ (874)	$ (1,975,342)
Ending Balance, shares at Sep. 30, 2023		96,251,844

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2023

Earnings Per Share [Abstract]

Instruments Excluded from the Computation of Diluted Net Loss Per Share

The following instruments were excluded from the computation of diluted net loss per share for the periods presented because their effect would have been antidilutive (in thousands):


	September 30, 2023		September 30, 2022
Options to purchase common stock		12,163		10,838
Warrants to purchase common stock		13		13
Restricted stock and performance units		1,401		1,275
Shares issuable related to the ESPP		64		41
Shares issuable upon conversion of 2026 Notes		2,554		2,554
Shares issuable upon conversion of 2027 Notes		13,744		10,572
Total shares		29,939		25,293

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Reconciliation of Cash, Cash Equivalents, and Restricted Cash Equivalents


	September 30, 2023		December 31, 2022
Cash and cash equivalents	$	99,692	$	65,582
Restricted cash		375		1,600
Total cash, cash equivalents, and restricted cash as reported within our consolidated statement of cash flows	$	100,067	$	67,182

Summary of Accrued Liabilities

Accrued liabilities were as follows (in thousands):


	September 30, 2023		December 31, 2022
Accrued liabilities:
Clinical and preclinical costs	$	4,327	$	16,105
Compensation related		22,352		21,767
Other accrued expenses		6,275		6,224
Total accrued liabilities	$	32,954	$	44,096

Fair Value Measurements - Summary of Fair Value of Financial Assets Consists of Cash Equivalents and Investments Classified as Available-for-sale Securities Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - Cash and Cash Equivalents and Investments [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 551,220	$ 829,184
Unrealized Gains	52	40
Unrealized Losses	(926)	(3,631)
Fair Value	550,346	825,593
Money Market Funds [Member] \| Fair Value Measurements Using Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	56,714	45,887
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	56,714	45,887
U.S. Treasury Securities [Member] \| Fair Value Measurements Using Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	55,029	172,568
Unrealized Gains	3	0
Unrealized Losses	(42)	(1,102)
Fair Value	54,990	171,466
U.S. Government agency securities \| Fair Value Measurements Using Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	167,184	129,174
Unrealized Gains	45	12
Unrealized Losses	(309)	(820)
Fair Value	166,920	128,366
U.S. Treasury Securities Backed Repurchase Agreements [Member] \| Fair Value Measurements Using Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost		16,003
Unrealized Gains		0
Unrealized Losses		0
Fair Value		16,003
Foreign government agency securities \| Fair Value Measurements Using Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost		7,599
Unrealized Gains		0
Unrealized Losses		(69)
Fair Value		7,530
Commercial Paper [Member] \| Fair Value Measurements Using Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	219,468	329,359
Unrealized Gains	4	28
Unrealized Losses	(209)	(431)
Fair Value	219,263	328,956
Corporate Obligations [Member] \| Fair Value Measurements Using Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	52,825	128,594
Unrealized Gains	0	0
Unrealized Losses	(366)	(1,209)
Fair Value	$ 52,459	$ 127,385

Subsequent Events

9 Months Ended

Sep. 30, 2023

Subsequent Events [Abstract]

Subsequent Events

Note 10 — Subsequent Events

During the period October 1, 2023 through and inclusive of November 3, 2023, we issued 2,454,618 shares of our common stock for net proceeds of $80.3 million under the Amended ATM Facility.

Net Loss Per Share - Instruments Excluded from the Computation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	29,939	25,293
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	12,163	10,838
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	13	13
Restricted Stock and Performance Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	1,401	1,275
Shares Issuable Related to the ESSP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	64	41
2026 Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	2,554	2,554
2027 Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	13,744	10,572

Research and Development Arrangements - Additional Information (Detail) - USD ($)			3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 20, 2021	Apr. 23, 2020	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2023	Dec. 31, 2022	Jul. 14, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 378,000	$ 2,515,000	$ 5,858,000	$ 92,631,000
Accounts receivable			2,499,000		2,499,000					$ 147,000
Amount received as milestone payment					2,500,000
Net proceeds of issuance of common stock					1,312,000
Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Nonrefundable payment obligation	$ 50,000,000
Amount received as milestone payment	$ 50,000,000
Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable			2,500,000		2,500,000
Upfront payment received											$ 25,000,000
Royalty Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues				87,000,000		87,000,000
Sale of interest in future royalties											85,000,000
Fair Value of Royalty								$ 87,000,000
Long-term deferred revenue				87,000,000		87,000,000
Common Stock Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock upon private placement, shares	511,182
Shares Issued, price per share	$ 39.125
Net proceeds of issuance of common stock	$ 20,000,000
Common stock purchase agreement date	Dec. 20, 2021
Excess amount paid over the fair value of the shares	$ 4,900,000
Fair value of common stock	15,100,000
Maximum [Member] \| Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential additional payments receivable	330,000,000
Maximum [Member] \| Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential additional payments receivable											$ 200,000,000
2016 Astellas Amendment [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment of development costs for clinical trials of reldesemtiv		$ 12,000,000
Reimbursement of clinical development costs									$ 12,000,000
Rights Granted [Member] \| Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Nonrefundable payment obligation	40,000,000
New Drug Application [Member] \| Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Nonrefundable payment obligation	$ 10,000,000
License Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues							$ 54,900,000
License Revenues [Member] \| Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues							$ 0	$ 36,500,000
Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			378,000	2,515,000	3,358,000	4,631,000
Astellas [Member] \| Accounting Standards Update 2014-09
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable										$ 0
Astellas [Member] \| Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 0	$ 2,500,000	$ 2,700,000	$ 4,600,000

Agreements with Royalty Pharma - Schedule of Future Minimum Payments under Term Loan Agreement (Detail) - RP Loan Agreement [Member] $ in Thousands	Sep. 30, 2023 USD ($)
Debt Instrument [Line Items]
2023 remainder	$ 1,440
2024	10,080
2025	11,520
2026	11,520
2027	11,520
Thereafter	48,960
Future minimum payments	95,040
Less: Unamortized interest and loan costs	26,457
Term Loan, net	$ 68,583

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Nov. 03, 2023	Sep. 30, 2023
Subsequent Event [Line Items]
Net proceeds of issuance of common stock		$ 1,312
Subsequent Events [Member] \| Amended ATM Facility [Member]
Subsequent Event [Line Items]
Issuance of common stock under at-the-market offering, net of issuance costs, shares	2,454,618
Net proceeds of issuance of common stock	$ 80,300

Debt (Tables)

9 Months Ended

Sep. 30, 2023

Debt Disclosure [Abstract]

Schedule of Interest Cost Relating to Notes

The following table presents the total amount of interest cost recognized relating to the 2026 Notes (in thousands):


	Three Months Ended September 30, 2023		Three Months Ended September 30, 2022		Nine Months Ended September 30, 2023		Nine Months Ended September 30, 2022
Contractual interest expense	$	211	$	294	$	633	$	3,054
Amortization of debt issuance costs		29		19		79		328
Total interest expense recognized	$	240	$	313	$	712	$	3,382

The following table presents the total amount of interest cost recognized relating to the 2027 Notes (in thousands):


	Three Months Ended				Nine Months Ended
	September 30, 2023		September 30, 2022		September 30, 2023		September 30, 2022
Contractual interest expense	$	4,726	$	4,462	$	14,175	$	4,462
Amortization of debt issuance costs		817		749		2,248		749
Total interest expense recognized	$	5,543	$	5,211	$	16,423	$	5,211

Schedule of Maturities of Notes

Future minimum payments under the 2027 Notes and 2026 Notes are (in thousands):


Years ending December 31:	2027 Notes			2026 Notes
2023 remainder	$	—		$	423
2024		18,900			845
2025		18,900			845
2026		18,900			21,978
2027		558,900			—
Future minimum payments		615,600			24,091
Less: Interest		(75,600	)		(2,960	)
Convertible notes, principal amount		540,000			21,131
Less: Debt issuance costs on the convertible notes		(12,624	)		(373	)
Net carrying amount of the convertible notes	$	527,376		$	20,758

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues:
Total revenues	$ 378	$ 2,515	$ 5,858	$ 92,631
Operating expenses:
Research and development	82,532	62,734	245,147	165,795
General and administrative	40,111	48,222	129,498	124,008
Total operating expenses	122,643	110,956	374,645	289,803
Operating loss	(122,265)	(108,441)	(368,787)	(197,172)
Interest expense	(7,136)	(6,804)	(21,142)	(12,357)
Loss on extinguishment of debt	0	(22,246)	0	(24,939)
Non-cash interest expense on liabilities related to revenue participation right purchase agreements	(6,860)	(8,963)	(19,462)	(22,530)
Interest and other income, net	6,839	4,144	20,043	5,423
Net loss	$ (129,422)	$ (142,310)	$ (389,348)	$ (251,575)
Net loss per share - basic	$ (1.35)	$ (1.52)	$ (4.07)	$ (2.85)
Net loss per share - diluted	$ (1.35)	$ (1.52)	$ (4.07)	$ (2.85)
Weighted-average number of shares used in computing net loss per share - basic	96,071	93,758	95,666	88,195
Weighted-average number of shares used in computing net loss per share - diluted	96,071	93,758	95,666	88,195
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities, net	$ 584	$ (1,065)	$ 2,716	$ (4,690)
Comprehensive loss	(128,838)	(143,375)	(386,632)	(256,265)
Research and Development Revenues [Member]
Revenues:
Total revenues	378	2,515	3,358	4,631
Milestone Revenues [Member]
Revenues:
Total revenues	0	0	2,500	1,000
Realization of Revenue Participation Right Purchase Agreement [Member]
Revenues:
Total revenues	$ 0	$ 0	$ 0	$ 87,000

Stockholders' Equity - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Mar. 01, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation expense	$ 18,700	$ 13,200	$ 52,600	$ 34,400
Net proceeds of issuance of common stock			$ 1,312
Cantor [Member] \| Amended ATM Facility [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock under at-the-market offering, net of issuance costs, shares	38,431		38,431
Net proceeds of issuance of common stock	$ 1,300		$ 1,300
Maximum offering price of common stock under At The Market agreement					$ 300,000
Maximum percentage commission to be paid on gross proceedings under at the market agreement					3.00%
2004 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term to grant nonstatutory stock options and incentive stock options			10 years
Option grant prices as percentage of the fair market value of the common stock			100.00%
Percentage of options grant to new employees			25.00%
Shares available for grant	7,600,000		7,600,000
2004 Plan [Member] \| New Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting right			Options granted to new employees generally vest 25% after one year and monthly thereafter over a period of four years
Period from percentage of stock option vested			1 year
Vesting period			4 years
2004 Plan [Member] \| Existing Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting right			Options granted to existing employees generally vest monthly over a period of four years
Vesting period			4 years

Agreements with Royalty Pharma

9 Months Ended

Sep. 30, 2023

Agreements with Royalty Pharma [Abstract]

Agreements with Royalty Pharma

Note 6 — Agreements with Royalty Pharma

On January 7, 2022, we announced that we had entered into the 2022 RPI Transactions with affiliates of Royalty Pharma International plc.

The RP Loan Agreement and the RP Aficamten RPA described below, are determined to be debt instruments subsequently measured at amortized cost and were entered into with parties that were at the time of our entry into the 2022 RPI Transactions affiliated and in contemplation of one another. We used the relative fair value method and made separate estimates of the fair value of each freestanding financial instrument and then allocated the proceeds in proportion to those fair value amounts. Arrangement consideration for the RP Loan Agreement and the RP Aficamten RPA totaled $150 million, consisting of the two $50 million upfront payments for the signing of the RP Loan Agreement and the RP Aficamten RPA and milestone of $50 million for initiation of the first pivotal trial in oHCM for aficamten that was deemed probable at the signing of the agreements.

The initial consideration was allocated as follows (in thousands):


	Fair Value		Proceeds		Allocation
Units of Accounting:
Revenue Participation Right Purchase Agreement	$	69,498	$	100,000	$	89,571
Development Funding Loan Agreement		46,887		50,000		60,429
Total consideration	$	116,385	$	150,000	$	150,000

2022 RP Loan Agreement

Under the RP Loan Agreement, we were initially entitled to receive up to $300.0 million in term loans, $50.0 million of which was disbursed to us on closing and the remaining $250.0 million scheduled to have been available to us upon our satisfaction of customary disbursement conditions and certain development conditions by specific deadlines, as follows:

•

$50.0 million of tranche 2 term loans during the one year period following the receipt on or prior to March 31, 2023 of marketing approval from FDA of omecamtiv mecarbil;

•

$25.0 million of tranche 3 term loans during the one year period following the commercial availability of a diagnostic test measuring levels of omecamtiv mecarbil to support the final FDA label language applicable to such drug, subject to such commercial availability and the conditions to the tranche 2 term loans having occurred on or prior to March 31, 2023;

•

$75.0 million of tranche 4 term loans during the one year period following the receipt on or prior to September 30, 2024 of positive results from SEQUOIA-HCM, the Phase 3 trial for aficamten; and

•

$100.0 million of tranche 5 term loans during the one year period following the acceptance by the FDA on or prior to March 31, 2025 of an NDA for aficamten, subject to the conditions to the tranche 4 term loans having occurred on or prior to September 30, 2024.

As a result of our receipt of a CRL on February 28, 2023, in connection to our NDA for omecamtiv mecarbil, we have not satisfied the conditions to the availability of the tranche 2 and tranche 3 loans under the RP Loan Agreement. The remaining $175.0 million under tranches 4 and 5 remain available for disbursement to us, subject to satisfaction of the conditions described above.

Each term loan under the RP Loan Agreement matures on the 10 year anniversary of the funding date for such term loan and is repayable in quarterly installments of principal, interest and fees commencing on the last business day of the seventh full calendar quarter following the calendar quarter of the applicable funding date for such term loan, with the aggregate amount payable in respect of each term loan (including interest and other applicable fees) equal to 190% of the principal amount of the term loan for the tranche 1, tranche 4 and tranche 5 term loans and 200% of the principal amount of the term loan for tranche 2 and tranche 3 term loans (such amount with respect to each term loan, “Final Payment Amount”). We accounted for amounts drawn under the RP Loan Agreement using the effective interest method which resulted in an effective interest rate of 7.65% over the ten-year term. As of the date of the prepayment or maturity of the term loan (or the date such prepayment or repayment is required to be paid), we will be required to pay an additional amount equal to $34.6 million accreted over the term of the loan.

We may prepay the term loans in full (but not in part) at any time at our option by paying an amount equal to the unpaid portion of Final Payment Amount for the outstanding term loans under the RP Loan Agreement; provided that if the conditions for either the tranche 4 term loans or the tranche 5 term loans have been met, we must have borrowed at least $50 million principal amount of the tranche 4 or 5 term loans. In addition, the term loans under the RP Loan Agreement are repayable in full at the option of either us or the lender in an amount equal to the unpaid portion of Final Payment Amount for the outstanding term loans upon a change of control of Cytokinetics.

Future minimum payments under the existing borrowing under RP Loan Agreement are (in thousands):


Years ending December 31:
2023 remainder	$	1,440
2024		10,080
2025		11,520
2026		11,520
2027		11,520
Thereafter		48,960
Future minimum payments		95,040
Less: Unamortized interest and loan costs		(26,457	)
Term Loan, net	$	68,583

As of September 30, 2023, the estimated fair value of our RP Loan Agreement was $56.5 million. The fair value was estimated based on Level 3 inputs.

2022 RP Aficamten Royalty Purchase Agreement

In addition, on January 7, 2022, we entered into the RP Aficamten RPA with RPI ICAV, pursuant to which RPI ICAV purchased rights to certain revenue streams from net sales of pharmaceutical products containing aficamten by us, our affiliates and our licensees in exchange for up to $150.0 million in consideration, $50.0 million of which was paid on the closing date, $50.0 million of which was paid to us in March 2022 following the initiation of the first pivotal trial in oHCM for aficamten, and $50.0 million of which was paid to us in September 2023 following the initiation of the first pivotal clinical trial in nHCM for aficamten. The RP Aficamten RPA also provides that the parties will negotiate terms for additional funding if we achieve proof of concept results in certain other indications for aficamten, with a reduction in the applicable royalty if we and RPI ICAV fail to agree on such terms in certain circumstances.

Pursuant to the RP Aficamten RPA, RPI ICAV purchased the right to receive a percentage of net sales equal to 4.5% for annual worldwide net sales of pharmaceutical products containing aficamten up to $1 billion and 3.5% for annual worldwide net sales of pharmaceutical products containing aficamten in excess of $1 billion, subject to reduction in certain circumstances. Our liability to RPI ICAV is referred to as the “RP Aficamten Liability”.

We account for the RP Aficamten Liability as a liability primarily because we have significant continuing involvement in generating the related revenue stream from which the liability will be repaid. If and when aficamten is commercialized and royalties become due, we will recognize the portion of royalties paid to RPI ICAV as a decrease to the RP Aficamten Liability and a corresponding reduction in cash.

The carrying amount of the RP Aficamten Liability is based on our estimate of the future royalties to be paid to RPI ICAV over the life of the arrangement as discounted using an imputed rate of interest. The imputed rate of interest on the unamortized portion of the RP Aficamten Liability was approximately 18.0% as of September 30, 2023 and 22.4% as of December 31, 2022.

During the first, second, and third quarter of 2023, we updated our analyses of the RP Aficamten RPA to reflect our assumptions resulting from ongoing global market research and to reflect other adjustments in connection with our anticipated commercialization, including the additional consideration of $50.0 million which was paid to us in September 2023 following the initiation of the first pivotal clinical trial in nHCM for aficamten. Our estimates regarding the amount of future royalty payments under the RP Aficamten RPA changed from the fourth quarter of 2022 due to changes in management’s estimates of unobservable inputs related to market conditions and timing to include projections of future royalty payments. The adjustment is accounted for on a prospective basis in our liability calculation and resulted in changes in our imputed interest rate and non-cash interest expense from 22.4% and $5.2 million in the fourth quarter of 2022, 22.4% and $5.4 million in the first quarter of 2023, 19.0% and $4.9 million in the second quarter of 2023, and to 18.0% and $5.4 million in the third quarter of 2023, respectively. During the nine months ended September 30, 2023, the change in estimate decreased our non-cash interest expense by $1.5 million.

2017 RP Omecamtiv Mecarbil Royalty Purchase Agreement

In February 2017, we entered into the RP OM RPA pursuant to which we sold a portion of our right to receive royalties from Amgen on future net sales of omecamtiv mecarbil to RPFT for a one-time payment of $90 million, which is non-refundable even if omecamtiv mecarbil is never commercialized. Concurrently, we entered into a common stock purchase agreement with RPFT through which RPFT purchased 875,656 shares of the Company’s common stock for $10.0 million. We allocated the consideration and issuance costs on a relative fair value basis to our liability to RPFT related to sale of future royalties under the RP OM RPA (the “RP OM Liability”) and the common stock sold to RPFT, which resulted in the RP OM Liability being initially recognized at $92.3 million. The RP OM RPA provides for the sale of a royalty to RPFT of 4.5% on worldwide net sales of omecamtiv mecarbil, subject to a potential increase of up to an additional 1% under certain circumstances. As a result of our receipt of a CRL on February 28, 2023 in connection to our NDA for omecamtiv mecarbil, pursuant to the terms of the RP OM RPA, the applicable royalty rate will increase to a maximum of 5.5% if omecamtiv approval obtains FDA approval at any time after June 30, 2023.

As a result of the termination of the Amgen Agreement and pursuant to our obligations under the RP OM RPA, we and RPFT amended the RP OM RPA on January 7, 2022 to preserve RPFT’s rights under the RP OM RPA by providing for direct payments by us to RPFT of up to 5.5% of our and our affiliates and licensees worldwide net sales of omecamtiv mecarbil. The RP OM RPA, as amended, had no impact on the original accounting for the $92.3 million associated with the RP OM Liability established in February 2017.

We account for the RP OM Liability as a liability primarily because we have significant continuing involvement in generating the related revenue stream from which the liability will be repaid. If and when omecamtiv mecarbil is commercialized and royalties become due, we will recognize the portion of royalties paid to RPFT as a decrease to the RP OM Liability and a corresponding reduction in cash.

The carrying amount of the RP OM Liability is based on our estimate of the future royalties to be paid to RPFT over the life of the arrangement as discounted using an imputed rate of interest. The excess of future estimated royalty payments over the $92.3 million of allocated proceeds, less issuance costs, is recognized as non-cash interest expense using the effective interest method. The imputed rate of interest on the unamortized portion of the RP OM Liability was approximately 2.9% as of September 30, 2023 and 8.5% as of December 31, 2022.

During the first and second quarter of 2023, we updated our analyses of the RP OM RPA to reflect our current assumptions resulting from ongoing global market research and to reflect other adjustments in connection with our anticipated commercialization, including the result of our receipt of a CRL in connection to our NDA for omecamtiv mecarbil. As a consequence of our receipt of the CRL from FDA, the royalty rate under the RP OM RPA will increase to no more than 5.5%. The resulting sales forecast for omecamtiv mecarbil has decreased year over year because commercialization and sales of omecamtiv mecarbil will be delayed. The adjustment is accounted for on a prospective basis in our liability calculation and resulted in changes in our imputed interest rate and non-cash interest expense from 8.5% and $4.0 million in the fourth quarter of 2022, 1.9% and $0.9 million in the first quarter of 2023, 2.9% and $1.4 million in the second quarter of 2023, respectively. We had no change in our estimates for the RP OM RPA in the third quarter of 2023 and the non-cash interest expense was $1.4 million for the three months ended September 30, 2023. During the nine months ended September 30, 2023, the change in estimate decreased our non-cash interest expense by $8.6 million.

Accounting for the Royalty Pharma Royalty Purchase Agreements

We periodically assess the amount and timing of expected royalty payments using a combination of internal projections and forecasts from external sources. To the extent such payments are greater or less than our initial estimates or the timing of such payments is materially different than its original estimates, we will prospectively adjust the amortization of the RP OM Liability and the RP Aficamten Liability and the effective interest rate.

There are a number of factors that could materially affect the amount and timing of royalty payments, a number of which are not within our control. The RP OM Liability and the RP Aficamten Liability are recognized using significant unobservable inputs. These inputs are derived using internal management estimates developed based on third party data, including competitor sales data, and reflect management’s judgments, current market conditions surrounding competing products, and forecasts. The significant unobservable inputs include the estimated patient population, estimated selling price, estimated peak sales and sales ramp, the expected term of the royalty stream, timing of the expected launch and its impact on the royalty rate as well as the overall probability of success. A significant change in unobservable inputs could result in a material increase or decrease to the effective interest rate of the RP OM Liability and the RP Aficamten Liability.

We recorded $50.0 million of additional consideration associated with the 2022 RP Aficamten Royalty Purchase Agreement upon receipt of the cash in the third quarter of 2023.

We review our assumptions on a regular basis and our estimates may change in the future as we refine and reassess our assumptions. For example, we expect to announce topline results from SEQUOIA-HCM and we may receive a response from the FDA related to our formal dispute resolution process for omecamtiv mecarbil by the end of the calendar year 2023.

Changes to the RP Aficamten Liability and the RP OM Liability are as follows (in thousands):


	2023				2022
	RP Aficamten Liability		RP OM Liability		RP Aficamten Liability		RP OM Liability
Beginning balance, January 1	$	105,117	$	195,384	$	—	$	179,072
Initial carrying value		—		—		89,571		—
Interest accretion		5,363		917		2,286		4,278
Amortization of issuance costs		—		33		—		28
Ending balance, March 31		110,480		196,334		91,857		183,378
Interest accretion		4,903		1,419		2,574		4,429
Amortization of issuance costs		—		27		—		28
Ending balance, June 30		115,383		197,780		94,431		187,835
Additional consideration		50,000		—		—		—
Interest accretion		5,415		1,445		5,469		3,494
Amortization of issuance costs		—		26		—		31
Ending balance, September 30	$	170,798	$	199,251	$	99,900	$	191,360

Agreements with Royalty Pharma - Schedule of Initial Consideration (Detail) - 2022 Royalty Pharma Transactions [Member] $ in Thousands	Jan. 07, 2022 USD ($)
Debt Instrument [Line Items]
Consideration Fair Value	$ 116,385
Consideration proceeds	150,000
Consideration allocation	150,000
Revenue Participation Right Purchase Agreements [Member]
Debt Instrument [Line Items]
Consideration Fair Value	69,498
Consideration proceeds	100,000
Consideration allocation	89,571
Development Funding Loan Agreement [Member]
Debt Instrument [Line Items]
Consideration Fair Value	46,887
Consideration proceeds	50,000
Consideration allocation	$ 60,429

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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