Cytokinetics (CYTK) 10-Q 9 Aug 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 07, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
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		117,659,578
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 190,142	$ 113,024
Short-term investments	866,633	501,800
Accounts receivable	0	1,283
Prepaid expenses and other current assets	11,035	11,944
Total current assets	1,067,810	628,051
Long-term investments	305,361	40,534
Property and equipment, net	65,689	68,748
Operating lease right-of-use assets	77,249	78,987
Other assets	7,679	7,996
Total assets	1,523,788	824,316
Current liabilities:
Accounts payable	9,470	21,507
Accrued liabilities	39,813	42,641
Short-term operating lease liabilities	18,507	17,891
Current portion of long-term debt	11,520	10,080
Derivative liabilities measured at fair value	13,200
Other current liabilities	10,267	10,559
Total current liabilities	102,777	102,678
Term loans, net	92,831	58,384
Convertible notes, net	550,600	548,989
Liabilities related to revenue participation right purchase agreements, net	435,112	379,975
Long-term operating lease liabilities	116,718	120,427
Liabilities related to RPI Transactions measured at fair value	117,200
Other non-current liabilities	0	186
Total liabilities	1,415,238	1,210,639
Commitments and contingencies
Stockholders' equity (deficit):
Preferred stock	0	0
Common stock	117	102
Additional paid-in capital	2,500,654	1,725,823
Accumulated other comprehensive loss	(1,022)	(10)
Accumulated deficit	(2,391,199)	(2,112,238)
Total stockholders' equity (deficit)	108,550	(386,323)
Total liabilities and stockholders' equity (deficit)	$ 1,523,788	$ 824,316

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Total revenues	$ 249	$ 867	$ 1,084	$ 5,480
Operating expenses:
Research and development	79,597	83,194	161,167	162,615
General and administrative	50,824	39,722	96,324	89,387
Total operating expenses	130,421	122,916	257,491	252,002
Operating loss	(130,172)	(122,049)	(256,407)	(246,522)
Interest expense	(12,732)	(7,045)	(19,835)	(14,006)
Non-cash interest expense on liabilities related to revenue participation right purchase agreements	(11,567)	(6,322)	(21,785)	(12,602)
Interest and other income, net	11,553	6,779	19,466	13,204
Change in fair value of derivative liabilities	(600)	0	(600)	0
Change in fair value of liabilities related to RPI Transactions	200	0	200	0
Net loss	$ (143,318)	$ (128,637)	$ (278,961)	$ (259,926)
Net loss per share - basic	$ (1.31)	$ (1.34)	$ (2.63)	$ (2.72)
Net loss per share - diluted	$ (1.31)	$ (1.34)	$ (2.63)	$ (2.72)
Weighted-average number of shares used in computing net loss per share - basic	109,240	95,755	106,013	95,461
Weighted-average number of shares used in computing net loss per share - diluted	109,240	95,755	106,013	95,461
Other comprehensive (loss) gain:
Unrealized (loss)/gain on available-for-sale securities, net	$ (499)	$ 187	$ (1,055)	$ 2,132
Foreign currency translation adjustments	16	0	43	0
Comprehensive loss	(143,801)	(128,450)	(279,973)	(257,794)
Research and Development Revenues [Member]
Revenues:
Total revenues	249	867	1,084	2,980
Milestone Revenues [Member]
Revenues:
Total revenues	$ 0	$ 0	$ 0	$ 2,500

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	At The Market Offering [Member]	Public Offering [Member]	Common Stock [Member]	Common Stock [Member] At The Market Offering [Member]	Common Stock [Member] Public Offering [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] At The Market Offering [Member]	Additional Paid-in Capital [Member] Public Offering [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member] At The Market Offering [Member]	Accumulated Other Comprehensive Loss [Member] Public Offering [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] At The Market Offering [Member]	Accumulated Deficit [Member] Public Offering [Member]
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)	(259,926)
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
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
Beginning Balance at Dec. 31, 2023	(386,323)			$ 102			1,725,823			(10)			(2,112,238)
Beginning Balance, shares at Dec. 31, 2023				101,637,922
Exercise of stock options, value	29,532			$ 2			29,530			0			0
Exercise of stock options, shares				1,466,359
Vesting of restricted stock units, value	0			$ 0			0			0			0
Vesting of restricted stock units, shares				695,140
Shares withheld related to net share settlement of equity awards, value	(18,449)			$ 0			(18,449)			0			0
Shares withheld related to net share settlement of equity awards, shares				(274,256)
Issuance of common stock, net of issuance costs, value		$ 93,640			$ 1			$ 93,639			$ 0			$ 0
Issuance of common stock, net of issuance costs, shares					1,237,460
Exercise of warrants, net, value	0			$ 0			0			0			0
Exercise of warrants, net, share				11,335
Stock-based compensation	21,612			$ 0			21,612			0			0
Other comprehensive income (loss)	(529)			0			0			(529)			0
Net Income (Loss)	(135,643)			0			0			0			(135,643)
Ending Balance at Mar. 31, 2024	(396,160)			$ 105			1,852,155			(539)			(2,247,881)
Ending Balance, shares at Mar. 31, 2024				104,773,960
Beginning Balance at Dec. 31, 2023	(386,323)			$ 102			1,725,823			(10)			(2,112,238)
Beginning Balance, shares at Dec. 31, 2023				101,637,922
Net Income (Loss)	(278,961)
Ending Balance at Jun. 30, 2024	108,550			$ 117			2,500,654			(1,022)			(2,391,199)
Ending Balance, shares at Jun. 30, 2024				117,525,034
Beginning Balance at Mar. 31, 2024	(396,160)			$ 105			1,852,155			(539)			(2,247,881)
Beginning Balance, shares at Mar. 31, 2024				104,773,960
Exercise of stock options, value	8,007			$ 0			8,007			0			0
Exercise of stock options, shares				356,281
Vesting of restricted stock units, value	0			$ 0			0			0			0
Vesting of restricted stock units, shares				46,034
Issuance of common stock under Employee Stock Purchase Plan, value	2,678			$ 0			2,678			0			0
Issuance of common stock under Employee Stock Purchase Plan, shares				93,857
Issuance of common stock, net of issuance costs, value			$ 563,204			$ 11			$ 563,193			$ 0			$ 0
Issuance of common stock, net of issuance costs, shares						11,274,510
Issuance of common stock in private placement, net of issuance costs, value	50,000			$ 1			49,999			0			0
Issuance of common stock in private placement, net of issuance costs, shares				980,392
Stock-based compensation	24,622			$ 0			24,622			0			0
Other comprehensive income (loss)	(483)			0			0			(483)			0
Net Income (Loss)	(143,318)			0			0			0			(143,318)
Ending Balance at Jun. 30, 2024	$ 108,550			$ 117			$ 2,500,654			$ (1,022)			$ (2,391,199)
Ending Balance, shares at Jun. 30, 2024				117,525,034

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities:
Net loss	$ (278,961)	$ (259,926)
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	21,837	12,662
Stock-based compensation expense	46,234	33,862
Non-cash lease expense	2,049	1,871
Depreciation of property and equipment	4,737	3,703
Change in fair value of derivative liabilities	600	0
Change in fair value of liabilities related to RPI Transactions	(200)	0
Realized gain on investment, net	0	35
Interest receivable and amortization on investments	(13,723)	(6,898)
Non-cash interest expense related to debt	4,541	13,871
Changes in operating assets and liabilities:
Accounts receivable	1,283	(838)
Prepaid and other assets	1,531	(7,279)
Accounts payable	(12,105)	(12,429)
Accrued and other liabilities	(1,406)	(19,181)
Operating lease liabilities	(3,404)	(194)
Other non-current liabilities	(1,833)	(3,350)
Net cash used in operating activities	(228,820)	(244,091)
Cash flows from investing activities:
Purchases of investments	(957,890)	(291,371)
Maturities of investments	340,898	535,138
Sales of investments	0	4,977
Purchases of property and equipment	(1,915)	(1,119)
Net cash (used in) provided by investing activities	(618,907)	247,625
Cash flows from financing activities:
Repayment of finance lease liabilities	(460)	(419)
Repayment of term loans	(3,350)	0
Proceeds from RPI Transactions	200,000	0
Proceeds from issuance of common stock related to private placement, net of issuance costs	50,000	0
Proceeds from issuance of common stock under equity incentive and stock purchase plans	40,217	9,234
Taxes paid related to net share settlement of equity awards	(18,449)	(10,517)
Net cash provided by financing activities	924,802	(1,702)
Effect of exchange rate changes on cash	43	0
Net increase (decrease) in cash, cash equivalents, and restricted cash	77,118	1,832
Cash, cash equivalents, and restricted cash, beginning of period	113,399	67,182
Cash, cash equivalents, and restricted cash, end of period	190,517	69,014
Supplemental cash flow disclosures:
Cash paid for interest	10,878	9,947
Non-cash investing and financing activities:
Right-of-use assets recognized in exchange for operating lease obligations	311	0
Amounts unpaid for purchases of property and equipment	68	0
At The Market Offering [Member]
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	93,640	0
Public Offering [Member]
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	$ 563,204	$ 0

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (143,318)	$ (135,643)	$ (128,637)	$ (131,289)	$ (278,961)	$ (259,926)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2024
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	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 2024 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.
Rule 10b5-1 Arrangement Adopted	false
Rule 10b51 Arr Modified Flag	false

Organization and Significant Ac

Organization and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2024
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 $ 2.4 billion since inception and there can be no assurance that we will attain profitability. We had a net loss of $ 279.0 million and net cash used in operations of $ 228.8 million for the six months ended June 30, 2024. Cash, cash equivalents, and investments increased to $ 1.4 billion as of June 30, 2024 from $ 0.7 billion as of December 31, 2023. 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 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, 2023 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, 2023 , 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 .

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	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): June 30, 2024 June 30, 2023 Options to purchase common stock 10,836 12,331 Warrants to purchase common stock — 13 Restricted stock and performance units 1,855 1,406 Shares issuable related to the ESPP 12 15 Shares issuable upon conversion of 2026 Notes 2,003 2,003 Shares issuable upon conversion of 2027 Notes 10,572 10,572 Total shares 25,278 26,340

Research and Development Arrang

Research and Development Arrangements	6 Months Ended
	Jun. 30, 2024
Research and Development [Abstract]
Research and Development Arrangements	Note 3 — Research and Development Arrangements 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 received a $ 50.0 million nonrefundable payment 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 FDA an NDA for omecamtiv mecarbil. 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 China and Taiwan 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. The Ji Xing OM License Agreement, unless terminated earlier, will continue on a market-by-market basis until expiration of the relevant royalty term. In addition to the Ji Xing OM License Agreement, we entered into common stock purchase agreements with each of the RTW Investors, pursuant to which we sold and issued an aggregate of 0.5 million shares of our common stock at a price per share of $ 39.125 and an aggregate purchase price of $ 20.0 million. The closing of the transaction occurred on December 31, 2021 . Ji Xing Aficamten License and Collaboration Agreement On July 14, 2020, we entered into the Ji Xing Aficamten License Agreement, 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. Under the terms of the Ji Xing Aficamten License Agreement, 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 pharmaceutical products containing aficamten in China and Taiwan, subject to certain reductions for generic competition, patent expiration and payments for licenses to third party patents. The Ji Xing Aficamten License Agreement, unless terminated earlier, will continue on a market-by-market basis until expiration of the relevant royalty term. Accounting for the Ji Xing License and Collaboration Agreements We assessed the arrangements of the Ji Xing OM License Agreement and the Ji Xing Aficamten License Agreement in accordance with ASC 606 and concluded that there is one performance obligation relating to the license of functional intellectual property for each agreement. The performance obligation was satisfied, and we recognized the residual allocation of arrangement consideration as revenue of $ 54.9 million in 2021 for the Ji Xing OM License Agreement and $ 36.5 million in 2020 for 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 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. We recognized a $ 2.5 million milestone from Ji Xing in 2023 for the initiation of a phase 3 clinical trial for aficamten in nHCM which was collected in the fourth quarter of 2023. Research and development revenue from Ji Xing was $ 0.2 million for the three months ended June 30, 2024, and $ 1.1 million and $ 0.3 million for the six months ended June 30, 2024 and 2023, respectively, related to certain development cost reimbursements. We had no research and development revenue from Ji Xing for the three months ended June 30, 2023. We had no accounts receivable from Ji Xing of as of June 30, 2024 and $ 0.3 million as of December 31, 2023. Astellas 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. Astellas also 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. As of December 31, 2023, we have billed and collected from Astellas up to the maximum contribution of $ 12.0 million. 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 and six months ended June 30, 2024. Research and development revenue from Astellas was $ 0.9 million and $ 2.7 million for the three and six months ended June 30, 2023 , respectively.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2024
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): June 30, 2024 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 72,288 $ — $ — $ 72,288 U.S. Treasury securities Level 1 344,391 52 ( 153 ) 344,290 U.S. Government agency securities Level 2 156,184 80 ( 170 ) 156,094 Commercial paper Level 2 510,543 1 ( 512 ) 510,032 Corporate obligations Level 2 264,411 3 ( 346 ) 264,068 $ 1,347,817 $ 136 $ ( 1,181 ) $ 1,346,772 December 31, 2023 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 77,429 $ — $ — $ 77,429 U.S. Treasury securities Level 1 34,625 13 ( 15 ) 34,623 U.S. Government agency securities Level 2 175,301 87 ( 133 ) 175,255 Commercial paper Level 2 252,956 156 ( 59 ) 253,053 Corporate obligations Level 2 92,384 103 ( 142 ) 92,345 $ 632,695 $ 359 $ ( 349 ) $ 632,705 No credit losses on debt securities were recognized during the six months ended June 30, 2024 or 2023. 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 unrealized losses as of June 30, 2024 are attributed to market interest rate changes and are not attributed to credit. 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. In May 2024, we entered into 2024 RPI Transactions and measured all of the liabilities issued at fair value, based on Level 3 inputs, on the date of issuance. In addition, the liabilities related to the 2024 RP OM Loan Agreement, the RP CK-586 RPA, and derivatives under the RP Multi Tranche Loan Agreement Amendment are remeasured on a recurring basis at fair value based on Level 3 inputs. See Note 6 Agreements with Royalty Pharma for further details.

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2024
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): June 30, 2024 December 31, 2023 Cash and cash equivalents $ 190,142 $ 113,024 Restricted cash 375 375 Total cash, cash equivalents, and restricted cash as reported within our consolidated statement of cash flows $ 190,517 $ 113,399 As of June 30, 2024, our restricted cash balance of $ 0.4 million is used to collateralize letters of credit. Accrued liabilities were as follows (in thousands): June 30, 2024 December 31, 2023 Accrued liabilities: Clinical and preclinical costs $ 10,516 $ 5,880 Compensation related 20,004 29,255 Other accrued expenses 9,293 7,506 Total accrued liabilities $ 39,813 $ 42,641

Agreements with Royalty Pharma

Agreements with Royalty Pharma	6 Months Ended
	Jun. 30, 2024
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. Pursuant to the 2022 RPI Transactions, the RP Multi Tranche 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 Multi Tranche Loan Agreement and the RP Aficamten RPA totaled $ 150 million, consisting of the two $ 50 million up front payments for the signing of the RP Multi Tranche 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. On May 22, 2024, we announced that we had entered into the 2024 RPI Transactions as an amendment to the 2022 RPI Transactions with affiliates of Royalty Pharma International plc. The 2024 RPI Transactions include the 2024 RP OM Loan Agreement, the RP CK-586 RPA, the RP Stock Purchase Agreement, the RP Multi Tranche Loan Agreement Amendment and the RP Aficamten RPA Amendment, as described below, are accounted for as a debt modification of the 2022 RPI Transactions. The 2024 RPI Transactions consideration of $ 200.0 million was allocated as follows (in thousands): Allocation Units of Accounting: RP Aficamten RPA $ 33,300 Tranche 6 of RP Multi Tranche Loan Agreement 41,200 Tranche 6 of RP Multi Tranche Loan Agreement - Embedded Derivatives 4,400 Tranche 4 of RP Multi Tranche Loan Agreement - Embedded Derivatives 3,700 RP CK-568 RPA 12,700 RP OM Loan Agreement 104,700 Total consideration $ 200,000 Liabilities Related to RPI Transactions Measured at Fair Value As permitted under Accounting Standards Codification 825, Financial Instruments, or ASC 825, we elected the fair value option for recognizing the liabilities related to the 2024 RP OM Loan Agreement and the RP CK-586 RPA. The fair value option was elected because these liabilities included embedded derivatives which would have otherwise required separate recognition and measurement. The Company elected the fair value option as it is believed to more practical for each liability as a single unit of account at fair value. Under the fair value option, debt issuance costs are expensed as incurred and the Company is required to record the fair value option elected arrangements at their fair value on the date of issuance and at each balance sheet thereafter. Changes in the estimated fair value of the arrangements are recognized as non-cash gains or losses in the statements of operations and comprehensive loss. RP OM Loan The RP OM Loan Agreement provides for a loan in a principal amount of $ 100.0 million that was drawn at the closing. The loan under the RP OM Loan Agreement matures on the 10 year anniversary of the funding date and is repayable in quarterly installments as follows: • Scenario 1: If the Phase 3 clinical trial of Cytokinetics’ proprietary small molecule cardiac myosin activator known as omecamtiv mecarbil is successful (defined as meeting the composite primary endpoint of the first event, whichever occurs first, comprising of cardiovascular death, heart failure event, LVAD implementation/cardiac transplantation, or stroke, with a hazard ratio (HR) of less than 0.85 and cardiovascular death endpoint HR of less than 1.0) by June 30, 2028 and we receive the marketing approval from the FDA for omecamtiv mecarbil on or prior to December 31, 2029 (“OM Approval Date”), commencing on the calendar quarter during which the FDA approval is obtained, we are required to pay RPDF (x) (i) $ 75.0 million ten business days after the OM Approval Date and (ii) $ 25.0 million on the first anniversary of the OM Approval Date and (y) on a quarterly basis an amount equal to 2.0 % of the annual worldwide net sales of omecamtiv mecarbil, subject to a minimum floor amount ranging from $ 5.0 million to $ 8.0 million during the first 18 calendar quarters (the payment of the 2.0 % of the annual worldwide net sales starting from the 19th calendar quarter shall be referred to as the “Royalty Payment”). Our obligation to pay the Royalty Payment will continue after maturity of the Loan; • Scenario 2: If the Phase 3 clinical trial of omecamtiv mecarbil is successful by June 30, 2028 but we have not received the marketing approval from the FDA for omecamtiv mecarbil on or prior to December 31, 2029, we are required to pay RPDF 18 equal quarterly cash payments totaling 237.5 % of the principal amount of the loan commencing on March 31, 2030 ; • Scenario 3: If the Phase 3 clinical trial of omecamtiv mecarbil is not successful by June 30, 2028, we are required to pay RPDF 22 equal quarterly cash payments totaling 227.5 % of the principal amount of the loan commencing on September 30, 2028 ; and • Scenario 4: If the Phase 3 clinical trial of omecamtiv mecarbil has not been initiated by June 30, 2026, we are required to pay RPDF 22 equal quarterly cash payments totaling 227.5 % of the principal amount of the loan commencing on September 30, 2026 ; (the aggregate amount to be paid by us with respect to each scenario is referred to as the “Scheduled Payment Amount”). The interest of the loan is included in the Scheduled Payment Amount for each scenario. In each scenario, we may prepay the loan in full (but not in part) at any time at its option by paying an amount equal to the unpaid portion of Scheduled Payment Amount for the outstanding loan; provided that, in scenario 1, we would be required to continue to pay the Royalty Payment after such prepayment. In addition, upon the occurrence of a change of control of the Company, the loan is repayable in full at the option of either the Company or the lender in an amount equal to (x) depending on when such change of control occurs, 150.0 % to 237.5 % of the principal amount of the loan minus (y) the then paid Scheduled Payment Amount. The RP OM Loan Agreement contains customary representations and warranties and customary affirmative and negative covenants applicable to the Company and its subsidiaries, including, among other things, restrictions on dispositions, mergers, indebtedness, encumbrances, distributions, stock repurchases, investments and transactions with affiliates. The RP OM Loan Agreement also includes customary events of default, including but not limited to the nonpayment of principal or interest, violations of covenants, material adverse changes, attachment, levy, restraint on business, cross-defaults on material indebtedness, bankruptcy, delisting, material judgments, misrepresentations, governmental approvals, payment defaults under other royalty purchase agreements and development funding agreements with RPDF or RPI ICAV. Upon an event of default or simultaneously with payment in full of the term loans in the RP OM Loan Agreement, the lenders may, among other things, accelerate the loan (with the amount payable between 227.5 % and 237.5 % of the principal amount (less amounts previously paid) in the case of other events of default). Upon execution of the RP OM Loan Agreement in the second quarter of 2024, we recorded liabilities of $ 104.7 million using the probability-weighted expected return method and the fair value inputs are classified as Level 3 in the fair value hierarchy. The following table demonstrates the future minimum payments for our RP OM Loan under Scenario 3, based on 227.5 % of the principal amount with repayment expected to start in 2028 as defined above, as of June 30, 2024 (in thousands): Years ending December 31: 2024 remainder $ — 2025 — 2026 — 2027 — 2028 20,682 Thereafter 206,818 Future minimum payments 227,500 As defined above, the minimum repayment schedule under Scenario 1 would be a total of 124.0 % of the principal amount and the royalty payment with quarterly payments starting in 2028. In addition, under Scenario 1 we would be obligated to make the royalty payment each quarter, and such amounts are not determinable at this time. The repayment schedule under Scenario 2 would be 237.5 % of the principal amount with quarterly payments starting in 2030, and Scenario 4 would be 227.5 % of the principal amount with quarterly payments starting in 2026. CK-586 RPA Pursuant to the RP CK-586 RPA, RPI ICAV purchased rights to certain revenue streams from worldwide net sales of CK-586 by us, our affiliates or licensees, in exchange for up to $ 200 million in consideration, $ 50 million of which was paid upfront and, following the initiation of the first Phase 3 clinical trial (or the Phase 3 portion of the first Phase 2b/3 clinical trial) in heart failure with preserved ejection fraction in humans for CK-586, at RPI ICAV’s sole discretion, up to in aggregate $ 150 million in quarterly payments to fund 50.0 % of the research and development cost of CK-586. Pursuant to the RP CK-586 RPA, RPI ICAV purchased the right to receive a percentage of net sales ranging from 1.0 % to up to 4.5 % for annual worldwide net sales of CK-586 (depending on the aggregate amounts funded by RPI ICAV), subject to reduction in certain circumstances, and will receive a 0.75x milestone payment upon market approval of CK-586 by the FDA, or if market approval of CK-586 by the European Medicines Agency is obtained prior to market approval by the FDA, 0.375x milestone payment for such obtained approval and 0.375x milestone payment upon subsequent market approval by the FDA. The RP CK-586 RPA contains customary representations, warranties and indemnities of the Company and RPI ICAV and customary covenants relating to the royalty payments. As the RP CK-586 RPA includes embedded derivative features that would require bifurcation, it meets the definition of a hybrid instrument. Upon execution of the RP CK-586 RPA in the second quarter of 2024, we recorded a liability of $ 12.7 million using a combination of the discounted cash flow method and the probability-weighted expected return method. The fair value inputs are classified as Level 3 in the fair value hierarchy. We account for the RP CK-586 RPA as a liability because, among other reasons, we have significant continuing involvement in generating the related revenue stream from which the liability will be repaid. Accounting for RPI Transactions Measured at Fair Value The fair values of the liabilities for the RP OM Loan Agreement and CK-586 RPA are based on significant unobservable inputs, including the probability of clinical success and regulatory approval based on historical industry success rates for product development specific to cardiovascular products, the estimated date of a product launch, estimates of pricing, sales ramp, variables for the timing of the related events, probability of change of control, and discount rates (which range from 13 % to 18 %), which are deemed to be Level 3 inputs in the fair value hierarchy. As products containing omecamtiv mecarbil and CK-586 have not yet been commercialized, the estimates are highly subjective. For example, assumed increases in the probability of the clinical success for the omecamtiv mecarbil or CK-586 programs could increase the value of the liabilities. For the three months ended June 30, 2024 , the Company recorded a gain of $ 0.2 million associated with the change in fair value of the liabilities related to 2024 RP OM Loan Agreement and the CK-586 RPA. The change in the fair value has been recognized in the statement of operations and comprehensive loss. The following table summarizes the changes of the fair value of the CK-586 RPA and RP OM Loan for the three months ended June 30, 2024 (in thousands): 2024 CK-586 RPA RP OM Loan Beginning balance, May 22 $ 12,700 $ 104,700 Change in fair value — ( 200 ) Ending balance, June 30 $ 12,700 $ 104,500 Liabilities Related to Revenue Participation Right Purchase Agreements RP Aficamten Royalty Purchase Agreement 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. Th e 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. On May 22, 2024, we entered into the RP Aficamten RPA Amendment to restructure the royalty so that RPI will now receive 4.5 % up to $ 5.0 billion of worldwide annual net sales of aficamten and 1 % above $ 5.0 billion of worldwide annual net sales. 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. In the second quarter of 2024, w e recorded an additional $ 33.3 million to the carrying value related to the 2024 RPI Transactions entered into May 22, 2024. The imputed rate of interest on the carrying value of the RP Aficamten Liability was approximately 24.3 % as of June 30, 2024 and 19.0 % as of June 30, 2023. 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 mecarbil 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 carrying value of the RP OM Liability was approximately 0.1 % as of June 30, 2024 and 2.9 % as of June 30, 2023. Accounting for Revenue Participation Right 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. The estimates of future royalties requires the use of several assumptions such as: the probability of clinical success, the probability of regulatory approval, the estimated date of a product launch, estimates of eligible patient populations, estimates of prescribing behavior and patient compliance behavior, estimates of pricing, payor reimbursement and coverage, and sales ramp. 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. In the second quarter of 2024, w e recorded an additional $ 33.3 million to the carrying value related to the 2024 RPI Transactions entered in May 22, 2024. We review our assumptions on a regular basis and our estimates may change in the future as we refine and reassess our assumptions. Changes to the RP Aficamten Liability and the RP OM Liability are as follows (in thousands): RP Aficamten Liability RP OM Liability 2024 2023 2024 2023 Beginning balance, January 1 $ 180,591 $ 105,117 $ 199,384 $ 195,384 Interest accretion 10,239 5,363 ( 21 ) 917 Amortization of issuance costs — — 26 33 Ending balance, March 31 $ 190,830 $ 110,480 $ 199,389 $ 196,334 Modification in the 2024 RPI Transactions 33,300 — — — Interest accretion 11,525 4,903 42 1,419 Amortization of issuance costs — — 26 27 Ending balance, June 30 $ 235,655 $ 115,383 $ 199,457 $ 197,780 RP Multi Tranche Term Loan Under the 2022 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 Multi Tranche Loan Agreement. In December 2023, we announced positive topline results from SEQUOIA-HCM, the Phase 3 trial for aficamten. This entitled us to draw $ 75.0 million under tranche 4 during the period April 4, 2024 through April 3, 2025, and requires us to complete a minimum mandatory draw of at least $ 50.0 million of the $ 75.0 million available during the same period. The remaining $ 100.0 million under tranche 5 remains available for disbursement to us, subject to satisfaction of the conditions described above. On May 22, 2024, we entered into the RP Multi Tranche Loan Agreement Amendment to provide for two tranches of additional term loans in an aggregate principal amount up to $ 225.0 million, consisting of a $ 50.0 million tranche 6 term loan drawn immediately and a $ 175.0 million tranche 7 term loan drawable at Cytokinetics’ discretion within one year of a future U.S. Food and Drug Administration (“FDA”) approval of aficamten in obstructive hypertrophic cardiomyopathy if such approval is obtained on or prior to December 31, 2025. Each term loan under the RP Multi Tranche 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, tranche 5, tranche 6, and tranche 7 term loans (such amount with respect to each term loan, “Final Payment Amount”). We account for amounts drawn under the RP Multi Tranche Loan Agreement using the effective interest method. The RP Multi Tranche Loan Agreement and amendment contains embedded derivative features. The fair values of the embedded derivatives are based on significant unobservable inputs, including the probability of change of control, the probability of default, discount rates and other factors. We have bifurcated and recognized the embedded derivatives as Derivative Liabilities Measured at Fair Value as discussed below. 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 Multi Tranche Loan Agreement. We must borrow at least $ 50 million principal amount of the tranche 4 within the applicable draw period. In addition, the term loans under the RP Multi Tranche 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 Tranche 1 and Tranche 6 of RP Multi Tranche Loan are (in thousands): Years ending December 31: Tranche 1 Term Loan Tranche 6 Term Loan 2024 remainder $ 5,760 $ — 2025 11,520 — 2026 11,520 8,640 2027 11,520 11,520 2028 11,520 11,520 Thereafter 37,440 63,320 Future minimum payments 89,280 95,000 Less: Unamortized interest and loan costs ( 26,786 ) ( 53,143 ) Term Loan, net $ 62,494 $ 41,857 The weighted-average effective rate of interest on the Tranche 1 and Tranche 6 term loans was approximately 11.6 % as of June 30, 2024. As of June 30, 2024, the estimated fair value of the Tranche 1 and Tranche 6 term loans was $ 51.2 million and $ 40.2 million , respectively. The fair value was estimated based on Level 3 inputs. Derivative Liabilities Measured at Fair Value We have bifurcated and recognized the embedded derivatives in the RP Multi Tranche Loan Agreement. These embedded derivatives include repayment features based upon a change in control and default. We recognize the derivative liabilities at fair value in the consolidated balance sheets. Each period, the fair value of the derivative liabilities will be recalculated and resulting gains and losses from the changes in fair value of the derivatives with non-credit components are recognized in income, while the change in fair value associated with credit components is recognized in accumulated other comprehensive loss. Estimating fair values of derivative instruments requires the development of significant and subjective estimates that may, and are likely to, change over the duration of the instrument with related changes in internal and external market factors. The fair values of the derivative liabilities is determined using the probability-weighted expected return method and the “with and without” method. The fair values are based on significant unobservable inputs, including the probability of change of control, the probability of default (less than 10 %), discount rates (ranging between 14 % to 16 %) and other factors. For the three months ended June 30, 2024 , the Company recorded a loss of $ 0.6 million associated with the change in fair value of the derivative liabilities. The amounts have been recorded as other expense in the condensed consolidated statement of operations and comprehensive loss. The following table summarizes the changes of the fair value of the derivative liabilities for the RP Multi Tranche Loan Agreement for three months ended June 30, 2024 (in thousands): RP Multi Tranche Loan Agreement Derivatives 2024 Beginning balance, May 22 $ 12,600 Change in fair value 600 Ending balance, June 30 $ 13,200 RP Stock Purchase Agreement Pursuant to the RP Stock Purchase Agreement, we, at our option, could require RPI ICAV to purchase shares of Common Stock for an aggregate purchase price of $ 50 million in our next equity financing on or before August 20, 2024, with minimum gross proceeds to us of $ 250 million. The Stock Purchase Agreement also includes lockup provisions. Concurrently with the closing of our underwritten public offering on May 28, 2024, RPI ICAV purchased 980,392 shares of Common Stock pursuant to the RP Stock Purchase Agreement at a price of $ 51.00 per share. The proceeds from the concurrent private placement were $ 50 million .

Debt

Debt	6 Months Ended
	Jun. 30, 2024
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 June 30, 2024 , there remains $ 21.1 million aggregate principal amount of 2026 Notes outstanding and $ 540.0 million of aggregate principal amount of 2027 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 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 we are not required to and no sinking fund is provided for the 2026 Notes. The 2026 Notes may be converted, under certain circumstances, 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 2027 Notes are our senior unsecured obligations and shares equal in right of payment with our other indebtedness, including the 2026 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. The conversion rate for the 2026 Notes and 2027 Notes will be subject to adjustment upon the occurrence of certain specified events as described above. 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. The 2026 Notes are redeemable, in whole or in part, at our option at any time, and from time to time, 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 (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. Holders of the 2027 Notes have the option to convert their convertible notes only in the following circumstances: (i) if the last reported sale price per share of our common stock exceeds 130 % of the conversion price for at least 20 trading days within a 30 -day period starting from the last trading day of the preceding quarter after September 30, 2022; (ii) within 5 consecutive business days following any 10 consecutive trading day period if the trading price per $ 1,000 principal amount of 2027 Notes during such period falls below 98 % of the product of the last reported sale price per share of our common stock and the conversion rate; (iii) upon certain corporate events or distributions on our common stock outlined in the 2027 Indenture; (iv) upon our call for redemption of the 2027 Notes; and (v) from March 1, 2027, until the scheduled trading day immediately preceding the maturity date. Circumstance (i) defined above was not triggered upon the calculation completed for July 1, 2024 . Consequently the 2027 Notes are not redeemable at the option of the holders for the second quarter of 2024. This calculation will continue to be r e-evaluated on a quarterly basis. 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. The following table presents the total amo unt of interest cost recognized relating to the 2026 Notes (in thousands): Three Months Ended Six Months Ended June 30, 2024 June 30, 2023 June 30, 2024 June 30, 2023 Contractual interest expense $ 211 $ 211 $ 423 $ 422 Amortization of debt issuance costs 28 27 56 50 Total interest expense recognized $ 239 $ 238 $ 479 $ 472 The effective interest rate of the 2026 Notes was 4.6 % for the three months ended June 30, 2024 and 2023. As of June 30, 2024, the unamortized debt issuance cost for the 2026 Notes was $ 0.3 million and will be amortized over approximately 2.4 years. The 2026 Notes are convertible at June 30, 2024 at the option of the holder. The following table presents the total amo unt of interest cost recognized relating to the 2027 Notes (in thousands): Three Months Ended Six Months Ended June 30, 2024 June 30, 2023 June 30, 2024 June 30, 2023 Contractual interest expense $ 4,725 $ 4,725 $ 9,450 $ 9,449 Amortization of debt issuance costs 782 749 1,555 1,431 Total interest expense recognized $ 5,507 $ 5,474 $ 11,005 $ 10,880 The effective interest rate of the 2027 Notes was 4.2 % as of June 30, 2024 and 2023. As of June 30, 2024, the unamortized debt issuance cost for the 2027 Notes was $ 10.2 million and will be amortized over approximately 3.0 years. During the six months ended June 30, 2024, the conditions allowing holders of the 2027 Notes to convert were not met. As a result, the 2027 Notes are not convertible during the six months ended June 30, 2024. Future minimum payments under the 2027 Notes and 2026 Notes are (in thousands): Years ending December 31: 2027 Notes 2026 Notes Total 2024 remainder $ 9,450 $ 423 $ 9,873 2025 18,900 845 19,745 2026 18,900 21,978 40,878 2027 558,900 — 558,900 Future minimum payments 606,150 23,246 629,396 Less: Interest ( 66,150 ) ( 2,113 ) ( 68,263 ) Convertible notes, principal amount 540,000 21,133 561,133 Less: Debt issuance costs on the convertible notes ( 10,243 ) ( 290 ) ( 10,533 ) Net carrying amount of the convertible notes $ 529,757 $ 20,843 $ 550,600 As of June 30, 2024, the estimated fair value of the 2027 Notes and 2026 Notes was $ 705.4 million and $ 109.7 million , respectively, and was based upon observable, Level 2 inputs, including pricing information from recent trades of the convertible notes.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Stockholders' Equity	Note 8 — Stockholders’ Equity Public Offering of Common Stock and Concurrent Private Placement On May 28, 2024, the Company closed an underwritten public offering of 9,803,922 shares of Common Stock at a public offering price of $ 51.00 per share, which included the exercise in full by the underwriters of their option to purchase up to 1,470,588 shares of Common Stock at the public offering price. The gross proceeds to the Company from the offering were approximately $ 575.0 million and net proceeds were approximately $ 563.2 million, after deducting the applicable underwriting discounts and commissions. Concurrently with the closing of the underwritten public offering, RPI ICAV purchased 980,392 shares of Common Stock pursuant to the RP Common Stock Purchase Agreement at a price of $ 51.00 per share in a concurrent private placement. The proceeds from the concurrent private placement were $ 50.0 million. 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 t akes place during the first quarter of each year. Our stock options and restricted stock units granted for the first quarter of 2024 was as follows: Grants Weighted Stock options 932,778 $ 64.54 Restricted stock units 1,037,398 $ 63.77 As of June 30, 2024, the total authorized shares under the 2004 Plan available for grant was 5.3 million . Total stock-based compensation expense was recorded in the condensed consolidated statements of operations and allocated as follows (in thousands): Three Months Ended Six Months Ended June 30, 2024 June 30, 2023 June 30, 2024 June 30, 2023 Research and development $ 11,475 $ 8,202 $ 20,103 $ 14,648 General and administrative 13,147 10,466 26,131 19,214 $ 24,622 $ 18,668 $ 46,234 $ 33,862 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. In 2023, we issued 5,016,170 shares of our common stock for net proceeds of $ 164.2 million under the Amended ATM Facility . There was no Amended ATM Facility activity during the three months ended June 30, 2024. W e issued 1,237,460 shares of our common stock for net proceeds of $ 93.6 million under the Amended ATM Facility for the six months ended June 30, 2024. Performance Stock Units In March, May, and June 2024, the Compensation Committee granted a total of 359,992 , 75,036 , and 5,537 performance stock units ("PSUs") to certain employees with a grant date fair value of $ 63.75 , $ 48.51 , and $ 54.18 per unit, respectively. The fair value of the PSUs was determined on the grant date based on the fair value of the Company’s common stock at such time. The PSU awards are subject to two performance goals and will be earned as to up to 50 % of the number of shares subject to the PSU award upon the certification by the Compensation and Talent Committee of the Company’s Board of Directors (the “Compensation Committee”) that the Company has achieved the first performance goal and as to up to 50 % of the number of shares subject to the PSU award upon the certification by the Compensation Committee that the Company has achieved the second performance goal, in each case vesting as to 50 % of the earned shares on applicable Compensation Committee certification date and as to 50 % of the earned shares following the one-year anniversary of the applicable Compensation Committee certification date. During the three and six months ended June 30, 2024, the Company recognized expense of $ 2.2 million and $ 2.5 million , respectively, for the PSUs. As of June 30, 2024, there was $ 10.9 million of unamortized stock-based compensation related to the PSUs. The Company will assess the probability of achievin g the performance conditions quarterly and the expense recognized will be adjusted accordingly.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2024
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, 2022, and 2023. The Oyster Point Lease commenced on March 31, 2021 and has an expiration date of October 31, 2033 .

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2024
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 $ 2.4 billion since inception and there can be no assurance that we will attain profitability. We had a net loss of $ 279.0 million and net cash used in operations of $ 228.8 million for the six months ended June 30, 2024. Cash, cash equivalents, and investments increased to $ 1.4 billion as of June 30, 2024 from $ 0.7 billion as of December 31, 2023. 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 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, 2023 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, 2023 , 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

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2024
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): June 30, 2024 June 30, 2023 Options to purchase common stock 10,836 12,331 Warrants to purchase common stock — 13 Restricted stock and performance units 1,855 1,406 Shares issuable related to the ESPP 12 15 Shares issuable upon conversion of 2026 Notes 2,003 2,003 Shares issuable upon conversion of 2027 Notes 10,572 10,572 Total shares 25,278 26,340

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2024
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	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): June 30, 2024 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 72,288 $ — $ — $ 72,288 U.S. Treasury securities Level 1 344,391 52 ( 153 ) 344,290 U.S. Government agency securities Level 2 156,184 80 ( 170 ) 156,094 Commercial paper Level 2 510,543 1 ( 512 ) 510,032 Corporate obligations Level 2 264,411 3 ( 346 ) 264,068 $ 1,347,817 $ 136 $ ( 1,181 ) $ 1,346,772 December 31, 2023 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 77,429 $ — $ — $ 77,429 U.S. Treasury securities Level 1 34,625 13 ( 15 ) 34,623 U.S. Government agency securities Level 2 175,301 87 ( 133 ) 175,255 Commercial paper Level 2 252,956 156 ( 59 ) 253,053 Corporate obligations Level 2 92,384 103 ( 142 ) 92,345 $ 632,695 $ 359 $ ( 349 ) $ 632,705

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reconciliation of Cash, Cash Equivalents, and Restricted Cash Equivalents	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): June 30, 2024 December 31, 2023 Cash and cash equivalents $ 190,142 $ 113,024 Restricted cash 375 375 Total cash, cash equivalents, and restricted cash as reported within our consolidated statement of cash flows $ 190,517 $ 113,399
Summary of Accrued Liabilities	Accrued liabilities were as follows (in thousands): June 30, 2024 December 31, 2023 Accrued liabilities: Clinical and preclinical costs $ 10,516 $ 5,880 Compensation related 20,004 29,255 Other accrued expenses 9,293 7,506 Total accrued liabilities $ 39,813 $ 42,641

Agreements with Royalty Pharma

Agreements with Royalty Pharma (Tables)	6 Months Ended
	Jun. 30, 2024
Debt Instrument [Line Items]
Schedule of Transactions Consideration	The 2024 RPI Transactions consideration of $ 200.0 million was allocated as follows (in thousands): Allocation Units of Accounting: RP Aficamten RPA $ 33,300 Tranche 6 of RP Multi Tranche Loan Agreement 41,200 Tranche 6 of RP Multi Tranche Loan Agreement - Embedded Derivatives 4,400 Tranche 4 of RP Multi Tranche Loan Agreement - Embedded Derivatives 3,700 RP CK-568 RPA 12,700 RP OM Loan Agreement 104,700 Total consideration $ 200,000
Summary of Changes of the Fair Value of Liabilities	The following table summarizes the changes of the fair value of the CK-586 RPA and RP OM Loan for the three months ended June 30, 2024 (in thousands): 2024 CK-586 RPA RP OM Loan Beginning balance, May 22 $ 12,700 $ 104,700 Change in fair value — ( 200 ) Ending balance, June 30 $ 12,700 $ 104,500
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): RP Aficamten Liability RP OM Liability 2024 2023 2024 2023 Beginning balance, January 1 $ 180,591 $ 105,117 $ 199,384 $ 195,384 Interest accretion 10,239 5,363 ( 21 ) 917 Amortization of issuance costs — — 26 33 Ending balance, March 31 $ 190,830 $ 110,480 $ 199,389 $ 196,334 Modification in the 2024 RPI Transactions 33,300 — — — Interest accretion 11,525 4,903 42 1,419 Amortization of issuance costs — — 26 27 Ending balance, June 30 $ 235,655 $ 115,383 $ 199,457 $ 197,780
Summary of Changes of Fair Value of Derivative Liabilities	The following table summarizes the changes of the fair value of the derivative liabilities for the RP Multi Tranche Loan Agreement for three months ended June 30, 2024 (in thousands): RP Multi Tranche Loan Agreement Derivatives 2024 Beginning balance, May 22 $ 12,600 Change in fair value 600 Ending balance, June 30 $ 13,200
RP OM Loan Agreement [Member]
Debt Instrument [Line Items]
Schedule of Future Minimum Payments under Loan Agreement	The following table demonstrates the future minimum payments for our RP OM Loan under Scenario 3, based on 227.5 % of the principal amount with repayment expected to start in 2028 as defined above, as of June 30, 2024 (in thousands): Years ending December 31: 2024 remainder $ — 2025 — 2026 — 2027 — 2028 20,682 Thereafter 206,818 Future minimum payments 227,500
RP Multi Tranche Loan [Member]
Debt Instrument [Line Items]
Schedule of Future Minimum Payments under Loan Agreement	Future minimum payments under the existing borrowing under Tranche 1 and Tranche 6 of RP Multi Tranche Loan are (in thousands): Years ending December 31: Tranche 1 Term Loan Tranche 6 Term Loan 2024 remainder $ 5,760 $ — 2025 11,520 — 2026 11,520 8,640 2027 11,520 11,520 2028 11,520 11,520 Thereafter 37,440 63,320 Future minimum payments 89,280 95,000 Less: Unamortized interest and loan costs ( 26,786 ) ( 53,143 ) Term Loan, net $ 62,494 $ 41,857

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Schedule of Interest Cost Relating to Notes	The following table presents the total amo unt of interest cost recognized relating to the 2026 Notes (in thousands): Three Months Ended Six Months Ended June 30, 2024 June 30, 2023 June 30, 2024 June 30, 2023 Contractual interest expense $ 211 $ 211 $ 423 $ 422 Amortization of debt issuance costs 28 27 56 50 Total interest expense recognized $ 239 $ 238 $ 479 $ 472 The following table presents the total amo unt of interest cost recognized relating to the 2027 Notes (in thousands): Three Months Ended Six Months Ended June 30, 2024 June 30, 2023 June 30, 2024 June 30, 2023 Contractual interest expense $ 4,725 $ 4,725 $ 9,450 $ 9,449 Amortization of debt issuance costs 782 749 1,555 1,431 Total interest expense recognized $ 5,507 $ 5,474 $ 11,005 $ 10,880
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 Total 2024 remainder $ 9,450 $ 423 $ 9,873 2025 18,900 845 19,745 2026 18,900 21,978 40,878 2027 558,900 — 558,900 Future minimum payments 606,150 23,246 629,396 Less: Interest ( 66,150 ) ( 2,113 ) ( 68,263 ) Convertible notes, principal amount 540,000 21,133 561,133 Less: Debt issuance costs on the convertible notes ( 10,243 ) ( 290 ) ( 10,533 ) Net carrying amount of the convertible notes $ 529,757 $ 20,843 $ 550,600

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2024
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Options and Restricted Stock Units Granted	Our annual grant of stock-based compensation t akes place during the first quarter of each year. Our stock options and restricted stock units granted for the first quarter of 2024 was as follows: Grants Weighted Stock options 932,778 $ 64.54 Restricted stock units 1,037,398 $ 63.77
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense was recorded in the condensed consolidated statements of operations and allocated as follows (in thousands): Three Months Ended Six Months Ended June 30, 2024 June 30, 2023 June 30, 2024 June 30, 2023 Research and development $ 11,475 $ 8,202 $ 20,103 $ 14,648 General and administrative 13,147 10,466 26,131 19,214 $ 24,622 $ 18,668 $ 46,234 $ 33,862

Organization and Significant _3

Organization and Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Accounting Policies [Abstract]
Accumulated deficit incurred	$ (2,391,199)				$ (2,391,199)		$ (2,112,238)
Cash requirements term					12 months
Net Income (Loss)	(143,318)	$ (135,643)	$ (128,637)	$ (131,289)	$ (278,961)	$ (259,926)
Cash, cash equivalents and investments	$ 1,400,000				1,400,000		$ 700,000
Net cash provided by (used in) operating activities					$ 228,820	$ 244,091

Net Loss Per Share - Instrument

Net Loss Per Share - Instruments Excluded from the Computation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	25,278	26,340
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	10,836	12,331
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	0	13
Restricted Stock and Performance Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	1,855	1,406
Shares Issuable Related to the ESSP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	12	15
2026 Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	2,003	2,003
2027 Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	10,572	10,572

Research and Development Arra_2

Research and Development Arrangements - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions			3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 20, 2021	Apr. 23, 2020	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2023	Jul. 14, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 249,000	$ 867,000	$ 1,084,000	$ 5,480,000
Accounts receivable			0		0				$ 1,283,000
Amount received as milestone payment					2,500,000
Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Nonrefundable payment obligation	$ 50,000,000
Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable			0		0				300,000
Upfront payment received										$ 25,000,000
Common Stock Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Shares Issued, price per share	$ 39.125
Shares, Issued	0.5
Net proceeds of issuance of common stock	$ 20,000,000
Common stock purchase agreement date	Dec. 31, 2021
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								$ 36,500,000
Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			249,000	867,000	1,084,000	2,980,000
Research and Development Revenues [Member] | Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			200,000		1,100,000	300,000
Astellas [Member] | Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 0	$ 900,000	$ 0	$ 2,700,000

Fair Value Measurements - Summa

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	Jun. 30, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 1,347,817	$ 632,695
Unrealized Gains	136	359
Unrealized Losses	(1,181)	(349)
Fair Value	1,346,772	632,705
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	72,288	77,429
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	72,288	77,429
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	344,391	34,625
Unrealized Gains	52	13
Unrealized Losses	(153)	(15)
Fair Value	344,290	34,623
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	156,184	175,301
Unrealized Gains	80	87
Unrealized Losses	(170)	(133)
Fair Value	156,094	175,255
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	510,543	252,956
Unrealized Gains	1	156
Unrealized Losses	(512)	(59)
Fair Value	510,032	253,053
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	264,411	92,384
Unrealized Gains	3	103
Unrealized Losses	(346)	(142)
Fair Value	$ 264,068	$ 92,345

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Credit losses on debt securities	$ 0	$ 0

Balance Sheet Components - Reco

Balance Sheet Components - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 190,142	$ 113,024
Restricted cash	375	375
Total cash, cash equivalents, and restricted cash as reported within our consolidated statement of cash flows	$ 190,517	$ 113,399	$ 69,014	$ 67,182

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents [Abstract]
Restricted cash	$ 375	$ 375

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Accrued liabilities:
Clinical and preclinical costs	$ 10,516	$ 5,880
Compensation related	20,004	29,255
Other accrued expenses	9,293	7,506
Total accrued liabilities	$ 39,813	$ 42,641

Agreements with Royalty Pharm_2

Agreements with Royalty Pharma - Additional Information (Detail) - USD ($) $ in Thousands

1 Months Ended

3 Months Ended

6 Months Ended

9 Months Ended

May 22, 2024

Jan. 07, 2022

Jun. 30, 2024

Mar. 31, 2022

Feb. 28, 2017

Jun. 30, 2024

Sep. 30, 2023

Jun. 30, 2023

Jun. 30, 2024

Sep. 30, 2023

Dec. 31, 2023

Jul. 01, 2023

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Long term debt

$ 629,396

$ 629,396

$ 629,396

Debt Instrument, Face Amount

561,133

561,133

561,133

Arrangement consideration of debt transaction

$ 150,000

Liabilities

1,415,238

1,415,238

1,415,238

$ 1,210,639

RP OM Loan Agreement [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Term loan, maturity year

10 years

Change in fair value of liabilities

200

Debt Instrument, Face Amount

$ 100,000

RP OM Loan Agreement [Member] | Level 3 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Liabilities at fair value

104,700

104,700

$ 104,700

RP OM Loan Agreement [Member] | Maximum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of change of control occur of principal amount of loan

237.50%

Percentage of amount payable of principal amount

237.50%

RP OM Loan Agreement [Member] | Minimum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of change of control occur of principal amount of loan

150%

Percentage of amount payable of principal amount

227.50%

RP OM Loan Agreement [Member] | Scenario 1 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Repayable loan percentage to principal amount

124%

Percentage of net sales payable

2%

Percentage of net sales payable for excess of annual worldwide net sales

2%

Payment of RPDF for ten business days after OM approval date

$ 75,000

Payment of RPDF for first anniversary after of OM approval date

25,000

RP OM Loan Agreement [Member] | Scenario 1 [Member] | Maximum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Subject to minimum floor amount

8,000

RP OM Loan Agreement [Member] | Scenario 1 [Member] | Minimum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Subject to minimum floor amount

$ 5,000

RP OM Loan Agreement [Member] | Scenario 2 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Number of RPDF equal quarterly

18 equal quarterly

Percentage of cash payments of principal amount

237.50%

Loan commencing, date

Mar. 31, 2030

Repayable loan percentage to principal amount

237.50%

RP OM Loan Agreement [Member] | Scenario 3 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Number of RPDF equal quarterly

22 equal quarterly

Percentage of cash payments of principal amount

227.50%

Loan commencing, date

Sep. 30, 2028

Repayable loan percentage to principal amount

227.50%

RP OM Loan Agreement [Member] | Scenario 4 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Number of RPDF equal quarterly

22 equal quarterly

Percentage of cash payments of principal amount

227.50%

Loan commencing, date

Sep. 30, 2026

Repayable loan percentage to principal amount

227.50%

RP CK-586 RPA, RPI ICAV [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of payment to fund of research and development cost

50%

Change in fair value of liabilities

200

Debt Instrument, Face Amount

$ 150,000

Purchased rights to certain revenue streams from net sales in consideration payment

50,000

RP CK-586 RPA, RPI ICAV [Member] | Level 3 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Liabilities at fair value

12,700

12,700

$ 12,700

RP CK-586 RPA, RPI ICAV [Member] | Maximum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of discount rates for fair values of derivative liabilities

18%

Purchased rights to certain revenue streams from net sales in consideration payment

$ 200,000

Percentage of net sales payable

4.50%

RP CK-586 RPA, RPI ICAV [Member] | Minimum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of discount rates for fair values of derivative liabilities

13%

Percentage of net sales payable

1%

RP Multi Tranche Loan [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of probability of default of derivative liabilities

10%

Derivative Liability

$ 12,600

13,200

13,200

$ 13,200

Change in fair value derivative liabilities

600

RP Multi Tranche Loan [Member] | Maximum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of discount rates for fair values of derivative liabilities

16%

RP Multi Tranche Loan [Member] | Minimum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Percentage of discount rates for fair values of derivative liabilities

14%

RP Multi Tranche Loan [Member] | Term Loan Tranche 1 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Long term debt

62,494

62,494

$ 62,494

RP Multi Tranche Loan [Member] | Term Loan Tranche 6 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Long term debt

$ 41,857

$ 41,857

$ 41,857

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%

4.50%

4.5% of net revenue to be receivable from annual worldwide net sales

$ 5,000,000

$ 1,000,000

Percentage of net sales payable for excess of annual worldwide net sales

1%

3.50%

1% of net sales payable for excess of annual worldwide net sales

$ 5,000,000

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

24.30%

24.30%

19%

24.30%

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 Multi Tranche Loan [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Term loan, maturity year

10 years

2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 1 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Estimated fair value of long term debt

$ 51,200

$ 51,200

$ 51,200

2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 4 [Member] | Minimum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Debt Instrument, Face Amount

$ 50,000

2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 6 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Estimated fair value of long term debt

$ 40,200

$ 40,200

$ 40,200

2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Tranche 1 and Tranche 6 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Weighted-average effective rate of interest

11.60%

11.60%

11.60%

2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 1 Tranche 4 Tranche 5 Tranche 6 and Tranche 7 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Repayable loan percentage to principal amount Including interest and other fees

190%

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

2024 RPI Transactions [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Consideration fair value allocation

$ 200,000

Additional carrying value

$ 33,300

Modification in 2024 RPI transactions

33,300

2024 RPI Transactions [Member] | RP OM Loan Agreement [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Change in fair value of liabilities

$ 200

2024 RPI Transactions [Member] | RP CK-586 RPA, RPI ICAV [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Change in fair value of liabilities

$ 0

Royalty Purchase Finance Trust Agreement [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Modification in 2024 RPI transactions

$ 0

$ 0

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

0.10%

0.10%

2.90%

0.10%

Non-cash interest expense recognized

$ 92,300

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]

Term loan, remaining borrowing capacity

75,000

Term loan, drawn amount

75,000

Long term debt

75,000

CRL Option [Member] | 2022 Royalty Pharma Transactions [Member] | RP Loan Agreement [Member] | Term Loan Tranche 4 [Member] | Minimum [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Term loan, current borrowing capacity

50,000

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]

Term loan, remaining borrowing capacity

$ 100,000

Long term debt

$ 100,000

CRL Option [Member] | 2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 6 and 7 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Term loan, maximum borrowing capacity

225,000

CRL Option [Member] | 2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 6 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Term loan, drawn amount

50,000

CRL Option [Member] | 2022 Royalty Pharma Transactions [Member] | RP Multi Tranche Loan [Member] | Term Loan Tranche 7 [Member]

Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]

Term loan, maximum 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%

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%

Agreements with Royalty Pharm_3

Agreements with Royalty Pharma - Additional Information (Detail 1) - USD ($) $ / shares in Units, $ in Thousands			6 Months Ended
	Aug. 20, 2024	May 28, 2024	Jun. 30, 2024	Jun. 30, 2023
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Net proceeds from issuance of private placement			$ 50,000	$ 0
RP Stock Purchase Agreement [Member] | Private Placement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Issuance of shares of common stock		980,392
Public offering price per share		$ 51
Gross proceeds from issuance of private placement		$ 50,000
RP Stock Purchase Agreement [Member] | Forecast [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Aggregate purchase price	$ 50,000
Gross proceeds from issuance of common stock	$ 250,000

Agreements with Royalty Pharm_4

Agreements with Royalty Pharma - Schedule of Transactions Consideration (Detail) - 2024 RPI Transactions [Member] $ in Thousands	May 22, 2024 USD ($)
Debt Instrument [Line Items]
Consideration allocation	$ 200,000
RP Aficamten RPA [Member]
Debt Instrument [Line Items]
Consideration allocation	33,300
Tranche 6 of RP Multi Tranche Loan Agreement [Member]
Debt Instrument [Line Items]
Consideration allocation	41,200
Tranche 6 of RP Multi Tranche Loan Agreement - Embedded Derivatives [Member]
Debt Instrument [Line Items]
Consideration allocation	4,400
Tranche 4 of RP Multi Tranche Loan Agreement - Embedded Derivatives
Debt Instrument [Line Items]
Consideration allocation	3,700
RP CK-568 RPA [Member]
Debt Instrument [Line Items]
Consideration allocation	12,700
RP OM Loan Agreement [Member]
Debt Instrument [Line Items]
Consideration allocation	$ 104,700

Agreements with Royalty Pharm_5

Agreements with Royalty Pharma - Schedule of Future Minimum Payments of Principal Amount with Repayment (Detail) $ in Thousands	Jun. 30, 2024 USD ($)
Debt Instrument [Line Items]
2024 remainder	$ 9,873
2025	19,745
2026	40,878
2027	558,900
RP OM Loan Agreement [Member]
Debt Instrument [Line Items]
2024 remainder	0
2025	0
2026	0
2027	0
2028	20,682
Thereafter	206,818
Future minimum payments	$ 227,500

Agreements with Royalty Pharm_6

Agreements with Royalty Pharma - Summary of Changes of Fair Value of Liabilities (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
RP CK-586 RPA, RPI ICAV [Member]
Debt Instrument [Line Items]
Change in fair value		$ (200)
RP OM Loan Agreement [Member]
Debt Instrument [Line Items]
Change in fair value		(200)
2024 RPI Transactions [Member] | RP CK-586 RPA, RPI ICAV [Member]
Debt Instrument [Line Items]
Beginning balance	$ 12,700
Change in fair value	0
Ending balance	12,700	12,700
2024 RPI Transactions [Member] | RP OM Loan Agreement [Member]
Debt Instrument [Line Items]
Beginning balance	104,700
Change in fair value	(200)
Ending balance	$ 104,500	$ 104,500

Agreements with Royalty Pharm_7

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				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
RP Aficamten Liability [Member]
Royalty Liability [Line Items]
Liabilities related to revenue participation right purchase agreements, net beginning balance	$ 190,830	$ 180,591	$ 110,480	$ 105,117	$ 180,591	$ 105,117
Modification in 2024 RPI transactions	33,300		0
Interest accretion	11,525	10,239	4,903	5,363
Amortization of issuance costs	0	0	0	0
Liabilities related to revenue participation right purchase agreements, net ending balance	235,655	190,830	115,383	110,480	235,655	115,383
RPOM Liability [Member]
Royalty Liability [Line Items]
Liabilities related to revenue participation right purchase agreements, net beginning balance	199,389	199,384	196,334	195,384	199,384	195,384
Modification in 2024 RPI transactions	0		0
Interest accretion	42	(21)	1,419	917
Amortization of issuance costs	26	26	27	33
Liabilities related to revenue participation right purchase agreements, net ending balance	$ 199,457	$ 199,389	$ 197,780	$ 196,334	$ 199,457	$ 197,780

Agreements with Royalty Pharm_8

Agreements with Royalty Pharma - Schedule of Future Minimum Payments under Loan Agreement (Detail) $ in Thousands	Jun. 30, 2024 USD ($)
Debt Instrument [Line Items]
2024 remainder	$ 9,873
2025	19,745
2026	40,878
2027	558,900
Less: Unamortized interest and loan costs	(10,533)
Term Loan, net	629,396
RP Multi Tranche Loan [Member] | Term Loan Tranche 1 [Member]
Debt Instrument [Line Items]
2024 remainder	5,760
2025	11,520
2026	11,520
2027	11,520
2028	11,520
Thereafter	37,440
Future minimum payments	89,280
Less: Unamortized interest and loan costs	(26,786)
Term Loan, net	62,494
RP Multi Tranche Loan [Member] | Term Loan Tranche 6 [Member]
Debt Instrument [Line Items]
2024 remainder	0
2025	0
2026	8,640
2027	11,520
2028	11,520
Thereafter	63,320
Future minimum payments	95,000
Less: Unamortized interest and loan costs	(53,143)
Term Loan, net	$ 41,857

Agreements with Royalty Pharm_9

Agreements with Royalty Pharma - Summary of Changes of Fair Value of Derivative Liabilities (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Derivatives, Fair Value [Line Items]
Change in fair value		$ (600)	$ 0	$ (600)	$ 0
RP Multi Tranche Loan Agreement Derivatives
Derivatives, Fair Value [Line Items]
Beginning balance	$ 12,600
Change in fair value	600
Ending balance	$ 13,200	$ 13,200		$ 13,200

Debt - Additional Information (

Debt - Additional Information (Detail)			6 Months Ended
	Jul. 06, 2022 USD ($) $ / shares shares	Nov. 13, 2019 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) Days	Jun. 30, 2023
Debt Instrument [Line Items]
Principal amount of original loan			$ 561,133,000
2026 Notes [Member]
Debt Instrument [Line Items]
Principal amount of original loan		$ 138,000,000	21,133,000
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
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		Nov. 15, 2026
Convertible debt, fair value			$ 109,700,000
Convertible notes, interest rate		4%
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
Convertible notes, percentage of conversion price			130%
Convertible notes, trading days | Days			20
Convertible notes, consecutive trading days | Days			30
Convertible notes, redemption description			The 2026 Notes are redeemable, in whole or in part, at our option at any time, and from time to time, 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 (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.
Debt instrument, unamortized debt issuance cost			$ 300,000
Unamortized debt discount amortization period			2 years 4 months 24 days
2026 Notes [Member] | Liability [Member]
Debt Instrument [Line Items]
Debt instrument effective interest rate			4.60%	4.60%
2027 Notes [Member]
Debt Instrument [Line Items]
Principal amount of original loan	540,000,000		$ 540,000,000
Payment associated with convertible notes	$ 140,300,000
Aggregate principal amount remaining			$ 540,000,000
Number of instalments description			payable semi-annually on May 15 and December 15 of each year, beginning May 15, 2020
Convertible notes, maturity date	Jul. 01, 2027
Convertible debt, fair value			$ 705,400,000
Convertible notes, interest rate	3.50%
Convertible notes, shares issued | shares	19.5783
Convertible notes, principal amount	$ 1,000
Convertible notes, initial conversion price | $ / shares	$ 51.08
Convertible notes, type of equity security issued	common stock
Convertible notes, conversion description	Holders of the 2027 Notes have the option to convert their convertible notes only in the following circumstances: (i) if the last reported sale price per share of our common stock exceeds 130% of the conversion price for at least 20 trading days within a 30-day period starting from the last trading day of the preceding quarter after September 30, 2022; (ii) within 5 consecutive business days following any 10 consecutive trading day period if the trading price per $1,000 principal amount of 2027 Notes during such period falls below 98% of the product of the last reported sale price per share of our common stock and the conversion rate; (iii) upon certain corporate events or distributions on our common stock outlined in the 2027 Indenture; (iv) upon our call for redemption of the 2027 Notes; and (v) from March 1, 2027, until the scheduled trading day immediately preceding the maturity date. Circumstance (i) defined above was not triggered upon the calculation completed for July 1, 2024.		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.
Convertible notes, redemption description			Consequently the 2027 Notes are not redeemable at the option of the holders for the second quarter of 2024. This calculation will continue to be re-evaluated on a quarterly basis. 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.
Debt instrument, unamortized debt issuance cost			$ 10,200,000
Unamortized debt discount amortization period			3 years
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]
Convertible notes, percentage of conversion price			130%
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%
Convertible notes, trading days | Days			5
Convertible notes, consecutive trading days | Days			10

Debt - Schedule of Interest Cos

Debt - Schedule of Interest Cost Relating to 2026 and 2027 Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
2026 Notes [Member]
Debt Instrument [Line Items]
Contractual interest expense	$ 211	$ 211	$ 423	$ 422
Amortization of debt issuance costs	28	27	56	50
Total interest expense recognized	239	238	479	472
2027 Notes [Member]
Debt Instrument [Line Items]
Contractual interest expense	4,725	4,725	9,450	9,449
Amortization of debt issuance costs	782	749	1,555	1,431
Total interest expense recognized	$ 5,507	$ 5,474	$ 11,005	$ 10,880

Debt - Schedule of Future Minim

Debt - Schedule of Future Minimum Payments under 2026 Notes and 2027 Notes (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jul. 06, 2022	Nov. 13, 2019
Debt Instrument [Line Items]
2024 remainder	$ 9,873
2025	19,745
2026	40,878
2027	558,900
Future minimum payments	629,396
Less: Interest	(68,263)
Convertible notes, principal amount	561,133
Less: Debt issuance costs on the convertible notes	(10,533)
Net carrying amount of the convertible notes	550,600	$ 548,989
2026 Notes [Member]
Debt Instrument [Line Items]
2024 remainder	423
2025	845
2026	21,978
2027	0
Future minimum payments	23,246
Less: Interest	(2,113)
Convertible notes, principal amount	21,133			$ 138,000
Less: Debt issuance costs on the convertible notes	(290)
Net carrying amount of the convertible notes	20,843
2027 Notes [Member]
Debt Instrument [Line Items]
2024 remainder	9,450
2025	18,900
2026	18,900
2027	558,900
Future minimum payments	606,150
Less: Interest	(66,150)
Convertible notes, principal amount	540,000		$ 540,000
Less: Debt issuance costs on the convertible notes	(10,243)
Net carrying amount of the convertible notes	$ 529,757

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)		1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended
	May 28, 2024 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) $ / shares shares	May 31, 2024 $ / shares shares	Mar. 31, 2024 $ / shares shares	Jun. 30, 2024 USD ($) shares	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) Tranche shares	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Mar. 01, 2023 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation expense					$ 24,622,000	$ 18,668,000	$ 46,234,000	$ 33,862,000
Unamortized/unrecognized stock-based compensation expense related to PSUs		$ 10,900,000			$ 10,900,000		$ 10,900,000
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 | shares		1,237,460			1,237,460		1,237,460		5,016,170
Net proceeds of issuance of common stock					$ 0		$ 93,600,000		$ 164,200,000
Maximum offering price of common stock under At The Market agreement										$ 300,000,000
Maximum percentage commission to be paid on gross proceedings under at the market agreement										3%
Public Offering [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Gross proceeds from issuance of common stock	$ 575,000,000
Net proceeds of issuance of common stock	563,200,000						$ 563,204,000	$ 0
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%
Percentage of options grant to new employees							25%
Shares available for grant | shares		5,300,000			5,300,000		5,300,000
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
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant | shares		5,537	75,036	359,992	5,537		5,537
Per unit weighted average grant date fair value | $ / shares		$ 54.18	$ 48.51	$ 63.75
Number of tranche | Tranche							2
Allocated share based compensation expense					$ 2,200,000		$ 2,500,000
Performance Stock Units [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share based payment award award vesting rights percentage							50%
Performance Stock Units [Member] | Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share based payment award award vesting rights percentage							50%
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Gross proceeds from issuance of private placement	$ 50,000,000
Common Stock [Member] | Private Placement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of shares of common stock | shares	980,392
Public offering price per share | $ / shares	$ 51
Common Stock [Member] | Public Offering [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of shares of common stock | shares	9,803,922				11,274,510
Public offering price per share | $ / shares	$ 51
Common Stock [Member] | Maximum [Member] | Underwriters Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of shares of common stock | shares	1,470,588

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Options and Restricted Stock Units Granted (Details)	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Employee Stock Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock options, Grants | shares	932,778
Stock options, Weighted average date fair value per share | $ / shares	$ 64.54
Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock units, Grants | shares	1,037,398
Restricted stock units, Weighted average date fair value per share | $ / shares	$ 63.77

Stockholder's Equity - Summary

Stockholder's Equity - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share based compensation expense	$ 24,622	$ 18,668	$ 46,234	$ 33,862
Research and Development [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share based compensation expense	11,475	8,202	20,103	14,648
General and Administrative [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share based compensation expense	$ 13,147	$ 10,466	$ 26,131	$ 19,214

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - Oyster Point Lease [Member] - California [Member]		6 Months Ended
	Mar. 31, 2021	Jun. 30, 2024
Lessee Lease Description [Line Items]
Operating lease, lease expiration date		Oct. 31, 2033
Operating lease, commencement date	Mar. 31, 2021