Cytokinetics (CYTK) 10-Q 6 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 04, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
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		85,652,213
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	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 115,422	$ 112,666
Short-term investments	493,552	358,972
Accounts receivable	6,056	51,819
Prepaid expenses and other current assets	8,496	12,215
Total current assets	623,526	535,672
Long-term investments	77,083	152,050
Property and equipment, net	75,740	73,271
Operating lease right-of-use assets	72,646	73,138
Other assets	7,258	7,188
Total assets	856,253	841,319
Current liabilities:
Accounts payable	19,836	21,087
Accrued liabilities	29,477	34,370
Short-term operating lease liabilities	14,490	14,863
Other current liabilities	3,044	1,540
Total current liabilities	66,847	71,860
Term loan, net	61,165	47,367
Convertible notes, net	134,511	95,471
Liabilities related to revenue participation right purchase agreements, net	275,235	179,072
Long-term deferred revenue	87,000	87,000
Long-term operating lease liabilities	112,023	112,229
Other non-current liabilities	3,211	4,457
Total liabilities	739,992	597,456
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value	0	0
Common stock, $0.001 par value	85	84
Additional paid-in capital	1,406,249	1,452,268
Accumulated other comprehensive loss	(3,589)	(869)
Accumulated deficit	(1,286,484)	(1,207,620)
Total stockholders’ equity	116,261	243,863
Total liabilities and stockholders’ equity	$ 856,253	$ 841,319

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Common stock, par value	$ 0.001	$ 0.001

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Total revenues	$ 1,148	$ 6,548
Operating expenses:
Research and development	45,935	31,561
General and administrative	33,070	15,598
Total operating expenses	79,005	47,159
Operating loss	(77,857)	(40,611)
Interest expense	(2,746)	(3,988)
Loss on extinguishment of debt	(2,693)	0
Non-cash interest expense on liabilities related to revenue participation right purchase agreements	(6,564)	(2,795)
Interest and other income, net	415	290
Net loss	$ (89,445)	$ (47,104)
Net loss per share - basic and diluted	$ (1.05)	$ (0.66)
Weighted-average number of shares used in computing net loss per share - basic and diluted	84,996	71,195
Other comprehensive loss:
Unrealized loss on available-for-sale securities, net	$ (2,720)	$ (99)
Comprehensive loss	(92,165)	(47,203)
Research and Development Revenues [Member]
Revenues:
Total revenues	$ 1,148	$ 6,548

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2020	$ 113,383	$ 70	$ 1,105,470	$ 149	$ (992,306)
Beginning Balance, shares at Dec. 31, 2020		71,015,183
Exercise of stock options, value	1,272	$ 1	1,271	0	0
Exercise of stock options, shares		187,807
Vesting of restricted stock units, net of taxes withheld, value	(4,449)	$ 0	(4,449)	0	0
Vesting of restricted stock units, net of taxes withheld, shares		360,050
Net share settlement	(418)	$ 0	(418)	0	0
Stock-based compensation	5,261	0	5,261	0	0
Other comprehensive income (Loss)	(99)	0	0	(99)	0
Net loss	(47,104)	0	0	0	(47,104)
Ending Balance at Mar. 31, 2021	67,846	$ 71	1,107,135	50	(1,039,410)
Ending Balance, shares at Mar. 31, 2021		71,563,040
Beginning Balance at Dec. 31, 2021	243,863	$ 84	1,452,268	(869)	(1,207,620)
Beginning Balance (ASU 2020-06) at Dec. 31, 2021	(38,895)		(49,476)	0	10,581
Beginning Balance, shares at Dec. 31, 2021		84,799,542
Exercise of stock options, value	4,075	$ 1	4,074	0	0
Exercise of stock options, shares		374,242
Vesting of restricted stock units, net of taxes withheld, value	(9,602)	$ 0	(9,602)	0	0
Vesting of restricted stock units, net of taxes withheld, shares		403,169
Stock-based compensation	8,985		8,985	0	0
Other comprehensive income (Loss)	(2,720)	$ 0	0	(2,720)	0
Net loss	(89,445)	0	0	0	(89,445)
Ending Balance at Mar. 31, 2022	$ 116,261	$ 85	$ 1,406,249	$ (3,589)	$ (1,286,484)
Ending Balance, shares at Mar. 31, 2022		85,576,953

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (89,445)	$ (47,104)
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	6,592	2,822
Non-cash stock-based compensation expense	8,985	5,261
Non-cash lease expense	227	1,124
Depreciation and amortization of property and equipment	1,341	537
Interest receivable and amortization on investments	1,004	933
Non-cash interest expense related to debt	1,300	1,676
Loss on extinguishment of debt	2,693	0
Changes in operating assets and liabilities:
Accounts receivable	50,763	(94)
Prepaid and other assets	(1,422)	2,677
Accounts payable	(3,080)	(4,047)
Accrued and other liabilities	(3,522)	(3,120)
Operating lease liabilities	(579)	9,816
Other non-current liabilities	(1,668)	0
Net cash used in operating activities	(26,811)	(29,519)
Cash flows from investing activities:
Purchases of investments	(193,127)	(66,200)
Maturities of investments	129,790	64,250
Sales of investments	0	3,300
Purchases of property and equipment	(942)	(6,626)
Net cash used in investing activities	(64,279)	(5,276)
Cash flows from financing activities:
Repayments of finance lease liabilities	(148)	0
Repayment of term loan	(47,651)	0
Debt extinguishment costs	(2,409)	0
Proceeds from 2020 RPI Transactions, net	149,581	0
Proceeds from and payments for stock-based award activities, net	(5,527)	(3,596)
Net cash provided by (used in) financing activities	93,846	(3,596)
Net increase in cash and cash equivalents	2,756	(38,391)
Cash and cash equivalents, beginning of period	112,666	82,985
Cash and cash equivalents, end of period	115,422	44,594
Non-cash investing and financing activities:
Cash paid for interest	2,714	868
Right-of-use assets recognized in exchange for lease obligations	0	77,887
Right-of-use assets recognized in exchange for finance lease obligations	703	0
Amounts unpaid for purchases of property and equipment	$ 1,829	$ 3,763

Organization and Significant Ac

Organization and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Significant Accounting Policies	Note 1 — Organization and Significant Accounting Policies Cytokinetics, Incorporated (the “Company”, “we” or “our”) 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 $ 1,286.5 million since inception and there can be no assurance that we will attain profitability. The Company anticipates that it will have operating losses and net cash outflows in future periods. We are subject to risks common to late stage biopharmaceutical companies including, but not limited to, development of new drug candidates, dependence on key personnel, and the ability to obtain additional capital as needed to fund our future plans. Our liquidity will be impaired if sufficient additional capital is not available on terms acceptable to us. To date, we have funded operations primarily through sales of our common stock, contract payments under our collaboration agreements, sales of future revenues and royalties, debt financing arrangements, government grants and interest income. Until we achieve profitable operations, we intend to continue to fund operations through payments from strategic collaborations, additional sales of equity securities, grants and debt financings. We have never generated revenues from commercial sales of our drugs and may not have drugs to market for at least several years, if ever. Our success is dependent on our ability to enter into new strategic collaborations and/or raise additional capital and to successfully develop and market one or more of our drug candidates. We cannot be certain that sufficient funds will be available from such a financing or through a collaborator when required or on satisfactory terms. Additionally, there can be no assurance that our drug candidates will be accepted in the marketplace or that any future products can be developed or manufactured at an acceptable cost. These factors could have a material adverse effect on our future financial results, financial position and cash flows. Based on the current status of our research and development activities, we believe that our existing cash, cash equivalents and investments will be sufficient to fund cash requirements for at least the next 12 months from the filing date 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 subsidiary. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“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, 2021 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, 2021 , as filed with the Securities and Exchange Commission. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires us 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 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. Recent Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt-Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging-Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). Under ASU 2020-06 the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives under Topic 815, Derivatives and Hedging, or that do not result in substantial premiums accounted for as paid-in capital. Consequently, a convertible debt instrument will be accounted for as a single liability measured at its amortized cost and convertible preferred stock will be accounted for as a single equity instrument measured at its historical cost, as long as no other features require bifurcation and recognition as derivatives. By removing those separation models, the interest rate of convertible debt instruments typically will be closer to the coupon interest rate. ASU 2020-06 also provides for certain disclosures with regard to convertible instruments and associated fair values. ASU 2020-06 is effective for annual reporting periods after December 15, 2021 and interim periods within those annual periods and early adoption is permitted. ASU 2020-06 provides companies with the option to adopt the new standard using either the full retrospective or modified retrospective method. We adopted this new guidance using the modified retrospective method as of January 1, 2022, with respect to our convertible senior notes due 2026 (the “2026 Notes”). The cumulative effect of initially applying the new standard was recognized as an adjustment to accumulated deficit. The following table summarizes the adjustments made to our condensed consolidated balance sheet as of January 1, 2022, upon adoption of the new standard: Balance sheet account description Ending Balance ASU 2020-06 Adjustments Beginning Balance Convertible notes, net $ 95,471 $ 38,895 $ 134,366 Additional paid-in capital 1,452,268 ( 49,476 ) 1,402,792 Accumulated deficit ( 1,207,620 ) 10,581 ( 1,197,039 ) The adoption of this new guidance resulted in an increase in the carrying value of the 2026 Notes to reflect the full principal amount of the convertible notes outstanding, net of issuance costs, a decrease in additional paid-in capital to remove the equity component separately recorded for the conversion feature associated with the convertible notes, a cumulative-effect adjustment to the beginning balance of our accumulated deficit as of January 1, 2022 to reverse the accretion of discount that resulted from the bifurcation of the equity component of the 2026 Notes, and a reversal of the related deferred tax liability of $ 8.3 million with a corresponding increase in our deferred tax asset valuation allowance. The adoption of this new guidance has reduced non-cash interest expense for the year ending December 31, 2022 and will continue to do so until the 2026 Notes have been settled. The remaining debt issuance costs will continue to be amortized over the term of the notes. We have recognized $ 1.5 million of interest expense of the 2026 Notes for the three months ended March 31, 2022, which is $ 1.4 million less than under the previous accounting standards. Without the adoption of ASU 2020-06, our reported net loss and net loss per share would increase by $ 1.4 million and $ 0.02 per share, respectively.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2022
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): March 31, 2022 March 31, 2021 Options to purchase common stock 10,855 9,508 Warrants to purchase common stock 47 48 Restricted stock and performance units 1,520 1,154 Shares issuable related to the ESPP 31 45 Shares issuable upon conversion of convertible notes 16,675 16,675 Total shares 29,128 27,430

Research and Development Arrang

Research and Development Arrangements	3 Months Ended
	Mar. 31, 2022
Research And Development [Abstract]
Research and Development Arrangements	Note 3 — Research and Development Arrangements 2021 Ji Xing and RTW Transactions The Ji Xing OM License Agreement, as defined below, and the sales of common stock to the RTW Investors, as defined below, in December 2021, as described below, (together the “2021 RTW Transactions”) were entered into with parties that were at the time of our entry into the 2021 RTW Transactions affiliated and in contemplation of one another and, accordingly, we have assessed the accounting for these transactions in the aggregate. Unconstrained arrangement consideration under the 2021 RTW Transactions totaled $ 70.0 million and was allocated in accordance with ASC 820 and ASC 606 as follows (in thousands): Allocated Units of Accounting: License and collaboration $ 54,856 Common stock (fair value) 15,144 Total consideration $ 70,000 Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement On December 20, 2021, we entered into a License and Collaboration Agreement (the “Ji Xing OM License Agreement”) with Ji Xing Pharmaceuticals Limited (“Ji Xing”), pursuant to which we granted to Ji Xing an exclusive license to develop and commercialize omecamtiv mecarbil in the People's Republic of China (including the Hong Kong and Macau Special Administrative Districts) (together “China”) and Taiwan. Under the terms of the Ji Xing OM License Agreement, we are the beneficiary of a nonrefundable $ 50.0 million payment obligation from Ji Xing comprised of a $ 40.0 million payment as consideration for the rights granted by us to Ji Xing and $ 10.0 million attributable to our having submitted to the U.S. Food and Drug Administration (the “FDA”) a new drug application (“NDA”) for omecamtiv mecarbil. The $ 50 million payment was received by the Company in January 2022. We may be eligible to receive from Ji Xing additional payments totaling up to $ 330.0 million for the achievement of certain commercial milestone events in connection to omecamtiv mecarbil. In addition, Ji Xing will pay us tiered royalties in the mid-teens to the low twenties range on the net sales of pharmaceutical products containing omecamtiv mecarbil in China and Taiwan, subject to certain reductions for generic competition, patent expiration and payments for licenses to third party patents. Ji Xing will be responsible for the development and commercialization of omecamtiv mecarbil at its own cost and is required to use diligent efforts to develop and commercialize omecamtiv mecarbil in China and Taiwan. The development of omecamtiv mecarbil will be initially focused on heart failure with reduced ejection fraction (“HFrEF”), and Ji Xing will have the opportunity to participate in Cytokinetics’ global clinical trials of omecamtiv mecarbil. Cytokinetics will supply omecamtiv mecarbil to Ji Xing either as a finished product or as an active pharmaceutical ingredient. The Ji Xing OM License Agreement, unless terminated earlier, will continue on a market-by-market basis until expiration of the relevant royalty term. Ji Xing has the right to terminate the Ji Xing OM License Agreement for convenience. Each party may terminate the Ji Xing OM License Agreement for the other party’s uncured material breach, insolvency, or failure to perform due to extended force majeure events. Cytokinetics may also terminate the Ji Xing OM License Agreement if Ji Xing challenges Cytokinetics’ patents or undergoes certain change of control transactions. Rights granted to Ji Xing in relation to omecamtiv mecarbil will revert to Cytokinetics upon termination, and, under certain circumstances, subject to a low single digit royalty payment by the Company to Ji Xing on the net sales of the products containing the compound omecamtiv mecarbil in China and Taiwan. We assessed this arrangement in accordance with ASC 606 and concluded that there is one performance obligation relating to the license of functional intellectual property. The performance obligation was satisfied, and we recognized the residual allocation of arrangement consideration as revenue of $ 54.9 million for 2021. Due to the nature of development, including the inherent risk of development and approval by regulatory authorities, we are unable to estimate if and when the development milestone payments could be achieved or become due and, accordingly, we consider the milestone payments to be fully constrained and excluded any potential milestone payments from the initial transaction price. The consideration related to sales-based milestone payments, including royalties, will be recognized when the related sales occur under the sales- and usage-based royalty exception as these amounts have been determined to relate predominantly to the license. We re-evaluate the probability of achievement of development milestones and any related constraints each reporting period. We will include consideration, without constraint, in the transaction price to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur. Common Stock Purchase Agreements On December 20, 2021, as part of the 2021 RTW Transactions, we entered into common stock purchase agreements with each of RTW Master Fund, Ltd., RTW Innovation Master Fund, Ltd. and RTW Venture Fund Limited (collectively, the “RTW Investors”). These common stock purchase agreements provided for the sale and issuance of an aggregate of 511,182 shares of our common stock at a price per share of $ 39.125 and an aggregate purchase price of $ 20.0 million. The closing occurred on December 20, 2021 . The RTW Investors have agreed to certain trading and other restrictions with respect to the shares of common stock they purchased pursuant to these agreements, including a restriction on sales or other transfers of the shares, subject to certain exceptions, for a period of one year from the closing date. The restrictions resulted in a premium paid by the RTW Investors of $ 4.9 million, which represents the excess amount paid over the fair value of the shares of common stock purchased. The premium was determined by analyzing the restrictions discount applied to the closing stock price as of December 20, 2021, which is a Level 2 fair value input. The cash received less the calculated premium is the $ 15.1 million fair value of the common stock recorded. 2020 Ji Xing and RTW Transactions On July 14, 2020, we entered into a series of transactions as described below with RTW Royalty Holdings Designated Activity Company (“RTW Royalty Holdings”) and Ji Xing, related to aficamten, our proprietary small molecule cardiac myosin inhibitor product, a novel cardiac myosin inhibitor, and other assets (together, the “2020 RTW Transactions”). The 2020 RTW Transactions include entering into a licensing and collaboration agreement with Ji Xing, the sale of Cytokinetics common stock to the RTW Investors, an agreement to sell to RTW Royalty Holdings our interest in certain future royalties on net sales of products containing the compound mavacamten that is being developed by Bristol-Myers Squibb Company (formerly by MyoKardia, Inc.), and the ability for the Company to obtain additional funding in the future from RTW Royalty Holdings, upon the achievement of certain clinical trial milestones, in exchange for future royalty payments as further discussed below. As a result, we have received and expect to receive a combination of license fees, milestone revenues and sale proceeds from the RTW Investors, RTW Royalty Holdings and Ji Xing. The 2020 RTW Transactions were entered into with parties that were at the time of our entry into the 2020 RTW Transactions affiliated and in contemplation of one another and, accordingly, we have assessed the accounting for these transactions in the aggregate. We concluded that there were three units of accounting in the 2020 RTW Transactions as further described below. The Company allocated the total consideration in accordance with ASC 820, Fair Value Measurement, and ASC 606, Revenue from Contracts with Customers, as follows (in thousands): Allocated Units of Accounting: License and collaboration (residual) $ 36,501 Royalty (fair value) 87,000 Common stock (fair value) 36,499 Total consideration $ 160,000 Ji Xing Aficamten License and Collaboration Agreement On July 14, 2020, we entered into a License and Collaboration Agreement (the “Ji Xing Aficamten License Agreement”) with Ji Xing, pursuant to which we granted to Ji Xing an exclusive license to develop and commercialize aficamten in China and Taiwan. Under the terms of the Ji Xing Aficamten License Agreement, we received from Ji Xing a nonrefundable upfront payment of $ 25.0 million. We may be eligible to receive from Ji Xing milestone payments totaling up to $ 200.0 million for the achievement of certain development and commercial milestone events in connection to aficamten in the field of obstructive hypertrophic cardiomyopathy (“oHCM”) and/or non-obstructive hypertrophic cardiomyopathy (“nHCM”) and other indications. In addition, Ji Xing will pay us tiered royalties in the low-to-high teens range on the net sales of the products containing aficamten in China and Taiwan, subject to certain reductions for generic competition, patent expiration and payments for licenses to third party patents. Ji Xing will be responsible for the development and commercialization of aficamten at its own cost and is required to use diligent efforts to develop and commercialize aficamten in China and Taiwan. The development of aficamten will be initially focused on hypertrophic cardiomyopathy, and Ji Xing will have the opportunity to participate in Cytokinetics’ global pivotal clinical trials of aficamten. Cytokinetics or a designated supplier will supply aficamten to Ji Xing either as a finished product or as an active pharmaceutical ingredient. The Ji Xing Aficamten License Agreement, unless terminated earlier, will continue on a market-by-market basis until expiration of the relevant royalty term. Ji Xing has the right to terminate the Ji Xing Aficamten License Agreement for convenience. Each party may terminate the Ji Xing Aficamten License Agreement for the other party’s uncured material breach, insolvency, or failure to perform due to extended force majeure events. Cytokinetics may also terminate the Ji Xing Aficamten License Agreement if Ji Xing challenges Cytokinetics’ patents or undergoes certain change of control transactions. Rights granted to Ji Xing in relation to aficamten will revert to Cytokinetics upon termination, and, under certain circumstances, subject to a low single digit royalty payment by the Company to Ji Xing on the net sales of the products containing the compound aficamten in China and Taiwan. We assessed this arrangement in accordance with ASC 606 and concluded that there is one performance obligation relating to the license of functional intellectual property. The performance obligation was satisfied, and we recognized the residual allocation of arrangement consideration as revenue of $ 36.5 million for 2020. No license revenue was recognized in 2021 related to the Ji Xing Aficamten License Agreement. Due to the nature of development, including the inherent risk of development and approval by regulatory authorities, we are unable to estimate if and when the development milestone payments could be achieved or become due and, accordingly, we consider the milestone payments to be fully constrained and exclude the milestone payments from the initial transaction pric e. 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 $ 5.0 million milestone from Ji Xing during the third quarter of 2021 for initiation of a phase 3 clinical trial for aficamten in oHCM. Although our contractual right to payment had not arisen under the Ji Xing Aficamten License Agreement, we determined recognition of the milestone in accordance with ASC 606 during the third quarter of 2021 was appropriate based on our expected initiation of a phase 3 clinical trial of aficamten in oHCM and was recorded as a corresponding contract asset in other current assets in our consolidated balance sheet as of December 31, 2021. The $ 5.0 million was reclassed to accounts receivable since we had a contractual right to payment as of March 31, 2022. Royalty Purchase Agreement On July 14, 2020, we entered into a Royalty Purchase Agreement (the “RTW Royalty Purchase Agreement”) with RTW Royalty Holdings, pursuant to which we sold our right to receive certain payments on the net sales of products containing the compound mavacamten, a cardiac myosin inhibitor (the “Mavacamten Royalty”), under the Research Collaboration Agreement, dated August 24, 2012, between us and MyoKardia, Inc. to RTW Royalty Holdings for a one-time payment of $ 85.0 million. The RTW Royalty Purchase Agreement transaction closed on November 13, 2020. On March 31, 2021, RTW Royalty Holdings assigned its rights and obligations under the RTW Royalty Purchase Agreement to its affiliate, RTW Investments ICAV for RTW Fund 1 (“RTW ICAV”). The allocation of the consideration for the 2020 RTW Transactions resulted in $ 87.0 million being allocated to the RTW Royalty Purchase Agreement representing its fair value. The fair value was determined using an income approach method based on ma nagement’s estimates of the discounted cash flows to be received over the term of the related royalty agreement, which are Level 3 fair value inputs. Management’s estimates included significant unobservable inputs. These inputs are derived using internal management estimates developed based on third party data and reflect management’s judgements, current market conditions surrounding competing products, and forecasts. The significant unobservable inputs include the estimated patient population, estimated selling price, estimated peak sales and sales ramp, the expected term of the royalty stream, and timing of the expected launch. The $ 87.0 million recorded as deferred revenue will be amortized using the units-of-revenue method. We will recognize revenue related to the sale of the Mavacamten Royalty using the units-of-revenue method when the product is commercialized. Under the units-of-revenue method, the revenue to be recognized for a period is calculated by computing a ratio of the Mavacamten Royalty paid to RTW Royalty Holdings for a given period to the total payments expected to be made to RTW Royalty Holdings over the term of the agreement, and then applying that ratio to the period's cash payment. We will record any adjustments due to changes in the underlying royalties on a cumulative catch-up basis. Common Stock Purchase Agreements On July 14, 2020, we entered into common stock purchase agreements with each of the RTW Investors. These common stock purchase agreements provided for the sale and issuance of an aggregate of 2.0 million shares of common stock of Cytokinetics at a price per share of $ 25.00 and an aggregate purchase price of $ 50.0 million. The closing occurred on July 14, 2020. The RTW Investors have agreed to certain trading and other restrictions with respect to the shares of common stock they purchased pursuant to these agreements, including a restriction on sales or other transfers of the shares, subject to certain exceptions, for a period of two years from the closing date, which period will be extended if certain conditions are met. The restrictions resulted in a premium paid by RTW investors of $ 13.5 million which represents the excess amount paid over the fair value of the shares of common stock purchased. The premium was determined by analyzing the holding period discount applied to the 30-day average stock price as of July 14, 2020 , which is a Level 2 fair value input. The cash received less the calculated premium is the $ 36.5 million fair value of the common stock recorded. Funding Agreement During July 2020, we also entered into a Funding Agreement (the “Funding Agreement”) with RTW Royalty Holdings. Pursuant to the Funding Agreement, RTW Royalty Holdings had committed to provide up to $ 90.0 million (the “RTW Funding Commitment”) to fund our development and commercialization of aficamten in nHCM and oHCM. On January 7, 2022, we announced that we h ad elected to unilaterally terminate the Funding Agreement in connection with our entry into the RP Aficamten RPA (as defined below). At the time of its termination, we had not exercised any rights to sell any revenue interest in aficamten under the Funding Agreement. Astellas Pharma Inc. (“Astellas”) Our strategic alliance with Astellas to advance novel therapies for diseases and medical conditions associated with skeletal muscle impairment and weakness commenced in 2013 under the License and Collaboration Agreement, dated June 21, 2013 between the parties (the “Astellas Agreement”). On April 23, 2020, we and Astellas entered into the two agreements referenced below which, taken together, amend and restate the Company’s research, development and commercialization collaboration with Astellas under the Astellas Agreement. Fast Skeletal Regulatory Activator Agreement The Company and Astellas entered into a Fast Skeletal Regulatory Activator Agreement, dated April 23, 2020 (the “Astellas FSRA Agreement”). 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 fast skeletal regulatory activator (collectively “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. In addition, Astellas agreed to non-cash contributions to the Company, which include the transfer of its existing inventories of active pharmaceutical ingredient of reldesemtiv and CK-601. Astellas has also agreed to the continued conduct of ongoing stability studies pertaining to such existing inventories of active pharmaceutical ingredient, at Astellas’ cost. In exchange, the Company will pay Astellas a low- to mid- single digit royalty on sales of reldesemtiv in the United States, Canada, United Kingdom and the European Union until the later of (i) ten years following the first commercial sale of such product in a major market country, or (ii) December 31, 2034, subject to certain royalty reduction provisions. The Company will not owe Astellas royalties on sales of reldesemtiv in any other country, or on the sale of any FSRA compounds or related products other than reldesemtiv. License and Collaboration Agreement for Other Skeletal Sarcomere Activators The Company and Astellas also entered into that certain License and Collaboration Agreement for Other Skeletal Sarcomere Activators, dated April 23, 2020 (the “Astellas OSSA Agreement”), which is an amendment and restatement of the Astellas Agreement and removes the FSRA compounds and related products from the collaboration. On April 27, 2021, we received written notice of termination from Astellas of the Astellas OSSA Agreement. The termination of the Astellas OSSA Agreement was effective November 1, 2021. We recognized research revenue for reimbursements from Astellas of internal costs of certain full-time employee equivalents, supporting collaborative research and development programs, and of other costs related to those programs through March 31, 2021 when the research term of the Astellas OSSA Agreement expired. Research and development revenue from Astellas was $ 1.1 million and $ 1.7 million for the three months ended March 31, 2022 and 2021, respectively. We had accounts receivable from Astellas of $ 1.1 million as of March 31, 2022 and $ 1.8 million as of December 31, 2021. Amgen Inc. (“Amgen”) On November 23, 2020, we received written notice of termination from Amgen of that certain Collaboration and Option Agreement, dated December 29, 2006, as amended (the “Amgen Agreement”) pertaining to the discovery, development and commercialization of novel small molecule therapeutics, including omecamtiv mecarbil, a novel cardiac myosin activator, and CK-136 (formerly AMG 594), a novel cardiac troponin activator. The termination of the Amgen Agreement was effective May 20, 2021. We recognized research and development revenue for reimbursements from Amgen of both internal costs of certain full-time employee equivalents and other costs related to the Amgen Agreement, which terminated effective May 20, 2021. There was no research and development revenue from Amgen for the three months ended March 31, 2022 and 2021.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
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): March 31, 2022 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 65,445 $ — $ — $ 65,445 U.S. Treasury securities Level 1 244,527 — ( 1,330 ) 243,197 U.S. and non-U.S. government agency bonds Level 2 24,892 — ( 162 ) 24,730 Commercial paper Level 2 188,023 — ( 264 ) 187,759 U.S. and non-U.S. corporate obligations Level 2 163,234 — ( 1,833 ) 161,401 $ 686,121 $ — $ ( 3,589 ) $ 682,532 December 31, 2021 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 115,937 $ — $ — $ 115,937 U.S. Treasury securities Level 1 133,498 1 ( 268 ) 133,231 U.S. and non-U.S. government agency bonds Level 2 33,489 — ( 53 ) 33,436 Commercial paper Level 2 169,622 6 ( 19 ) 169,609 U.S. and non-U.S. corporate obligations Level 2 175,282 — ( 536 ) 174,746 $ 627,828 $ 7 $ ( 876 ) $ 626,959 The available-for-sale securities in our condensed consolidated balance sheet are as follows (in thousands): March 31, 2022 December 31, 2021 Cash equivalents $ 111,897 $ 115,937 Short-term investments 493,552 358,972 Long-term investments 77,083 152,050 $ 682,532 $ 626,959 Interest income, net was $ 0.4 million and $ 0.3 million for three months ended March 31, 2022 and 2021, respectively. No credit losses on debt securities were recognized during the three months ended March 31, 2022 or 2021. In its evaluation to determine expected credit losses, management considered all available historical and current information, expectations of future economic conditions, the type of security, the credit rating of the security, and the size of the loss position, as well as other relevant information. The Company does not intend to sell, and is unlikely to be required to sell, any of these available-for-sale investments before their effective maturity or market price recovery. The carrying amount of our accounts receivable and accounts payable approximate fair value due to the short-term nature of these instruments. There were no transfers between Level 1, Level 2, and Level 3 during the periods presented.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	Note 5 — Balance Sheet Components Accrued liabilities were as follows (in thousands): March 31, 2022 December 31, 2021 Accrued liabilities: Clinical and preclinical costs $ 14,790 $ 13,872 Compensation related 9,824 14,930 Other accrued expenses 4,863 5,568 Total accrued liabilities $ 29,477 $ 34,370

Agreements with Royalty Pharma

Agreements with Royalty Pharma	3 Months Ended
	Mar. 31, 2022
Agreements With Royalty Pharma [Abstract]
Agreements with Royalty Pharma	Note 6 — Ag reements with Royalty Pharma On January 7, 2022, we announced that we had entered into the Development Funding Loan Agreement (the “RP Loan Agreement”) and the Revenue Participation Right Purchase Agreement (the “RP Aficamten RPA”) with Royalty Pharma Development Funding, LLC (“RPDF”) and Royalty Pharma Investments 2019 ICAV (“RPI ICAV”) (“2022 RPI Transactions”) respectively, each of which are affiliated with Royalty Pharma International plc. The RP Loan Agreement and the RP Aficamten RPA described below, are determined to be debt instruments subsequently measured at amortized cost and were entered into with parties that were at the time of our entry into the 2022 RPI Transactions affiliated and in contemplation of one another. We used the relative fair value method and made separate estimates of the fair value of each freestanding financial instrument and then allocated the proceeds in proportion to those fair value amounts. Arrangement consideration for the RP Loan Agreement and the RP Aficamten RPA totaled $ 150 million, consisting of the two $ 50 million upfront payments for the signing of the RP Loan Agreement and the RP Aficamten RPA and milestone of $ 50 million for initiation of the first pivotal trial in oHCM for aficamten that was deemed probable at the signing of the agreements. The total consideration was allocated as follows (in thousands): Fair Value Proceeds Allocation Units of Accounting: Revenue Participation Right Purchase Agreement $ 69,498 $ 100,000 $ 89,571 Development Funding Loan Agreement 46,887 50,000 60,429 Total consideration $ 116,385 $ 150,000 $ 150,000 2022 RP Loan Agreement Under the RP Loan Agreement, we are 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 is 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 December 31, 2022 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 December 31, 2022; • $ 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 a new drug application (“NDA”) for aficamten, subject to the conditions to the tranche 4 term loans having occurred on or prior to September 30, 2024. Each term loan under the RP Loan Agreement matures on the 10 year anniversary of the funding date for such term loan and is repayable in quarterly installments of principal, interest and fees commencing on the last business day of the seventh full calendar quarter following the calendar quarter of the applicable funding date for such term loan, with the aggregate amount payable in respect of each term loan (including interest and other applicable fees) equal to 190 % of the principal amount of the term loan (such amount with respect to each term loan, “Final Payment Amount”). We accounted for amounts drawn under the RP Loan Agreement using the effective interest method which resulted in an effective interest rate of 7.65 % over the ten year term. Upon the prepayment or maturity of the term loan (or upon the date such prepayment or repayment is required to be paid), we are required to pay an additional amount equal to $ 34.6 million. We may prepay the term loans in full (but not in part) at any time at our option by paying an amount equal to the unpaid portion of Final Payment Amount for the outstanding term loans under the RP Loan Agreement; provided that if the conditions for either the tranche 4 term loans or the tranche 5 term loans have been met, we must have borrowed at least $ 25 million principal amount of the tranche 4 or 5 term loans. In addition, the term loans under the RP Loan Agreement are repayable in full at the option of either us or the lender in an amount equal to the unpaid portion of Final Payment Amount for the outstanding term loans upon a change of control of Cytokinetics. Future minimum payments under the RP Loan Agreement are (in thousands): Years ending December 31: 2022 remainder $ — 2023 1,440 2024 10,080 2025 11,520 2026 11,520 Thereafter 60,480 Future minimum payments 95,040 Less: Unamortized interest and loan costs ( 33,875 ) Term Loan, net $ 61,165 As of March 31, 2022, the fair value of our RP Loan approximated its carrying va lue of $ 61.2 million ba sed upon a market observable interest rate, which is a Level 2 input. Interest expense for the RP Loan Agreement was $ 1.2 million for the three months ended March 31, 2022. Commensurate with our entry into the RP Loan Agreement, we terminated the Term Loan Agreement with Silicon Valley Bank and Oxford Finance LLC and repaid all amounts outstanding thereunder as further described in Note 7. 2022 RP Aficamten Royalty Purchase Agreement In addition, on January 7, 2022, we entered into the RP Aficamten RPA with RPI ICAV, pursuant to which RPI ICAV purchased rights to certain revenue streams from net sales of pharmaceutical products containing aficamten by us, our affiliates and our licensees in exchange for up to $ 150.0 million in consideration, $ 50.0 million of which was paid on the closing date, $ 50.0 million of which was paid to us in March 2022 following the initiation of the first pivotal trial in oHCM for aficamten and $ 50.0 million of which is payable following the initiation of the first pivotal clinical trial in nHCM for aficamten. The RP Aficamten RPA also provides that the parties will negotiate terms for additional funding if we achieve proof of concept results in certain other indications for aficamten, with a reduction in the applicable royalty if we and RPI ICAV fail to agree on such terms in certain circumstances. Pursuant to the RP Aficamten RPA, RPI ICAV purchased the right to receive a percentage of net sales equal to 4.5 % for annual worldwide net sales of pharmaceutical products containing aficamten up to $ 1 billion and 3.5 % for annual worldwide net sales of pharmaceutical products containing aficamten in excess of $ 1 billion, subject to reduction in certain circumstances (the “RP Aficamten Liability”). We account for the RP Aficamten Liability as a liability primarily because we have significant continuing involvement in generating the related revenue stream from which the liability will be repaid. If and when aficamten is commercialized and royalties become due, we will recognize the portion of royalties paid to RPI ICAV as a decrease to the RP Aficamten Liability and a corresponding reduction in cash. The carrying amount of the RP Aficamten Liability is based on our estimate of the future royalties to be paid to RPI ICAV over the life of the arrangement as discounted using an imputed rate of interest. The imputed rate of interest on the unamortized portion of the RP Aficamten Liability wa s approximately 11.7 % as of March 31, 2022. 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 RPI Finance Trust (“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. A s a result of the termination of the Amgen Agreement and pursuant to our obligations under the RP OM RPA, we and RPFT entered into Amendment No. 1 to Royalty Purchase Agreement, dated January 7, 2022 to preserve RPFT’s rights under the RP OM RPA by providing for direct payments by us to RPFT of 4.5 % of our and our affiliates and licensees worldwide net sales of omecamtiv mecarbil, subject to a potential increase of up to an additional 1 % under certain circumstances (if FDA approves omecamtiv mecarbil on its target PDUFA date of November 30, 2022, the royalty owed to RPFT will be 4.9 % of worldwide net sales of omecamtiv mecarbil). Amendment No. 1 to Royalty Purchase Agreement, dated January 7, 2022 had no impact on the original accounting for the $ 92.3 million associated with the RP OM Liability established in February 201 7. We account for the RP OM Liability as a liability primarily because we have significant continuing involvement in generating the related revenue stream from which the liability will be repaid. If and when omecamtiv mecarbil is commercialized and royalties become due, we will recognize the portion of royalties paid to RPFT as a decrease to the RP OM Liability and a corresponding reduction in cash. The carrying amount of the RP OM Liability is based on our estimate of the future royalties to be paid to RPFT over the life of the arrangement as discounted using an imputed rate of interest. The excess of future estimated royalty payments over the $92.3 million of allocated proceeds, less issuance costs, is recognized as non-cash interest expense using the effective interest method. The imputed rate of interest on the unamortized portion of the RP OM Liability was approximately 10 % as of March 31, 2022 and December 31, 2021. During the year ended December 31, 2021, we updated our analyses for the amount and timing of sales and royalties associated with omecamtiv mecarbil as a result of ongoing market research in the U.S. and to reflect other adjustments in connection with our anticipated commercialization plans. Our estimates regarding the amount of future royalty payments decreased and the time periods within which we anticipated that such payments will be due changed. Each of these adjustments is accounted for on a prospective basis in our liability calculation and resulted in a decline in our imputed interest rate and noncash interest expenses from 15 % and $ 22.7 million in 2020 to 10 % and $ 12.9 million in 2021, respectively. In 2021, the change in estimate had no impact on revenue and reduced the net loss by $ 11.5 million. The change in accounting estimate reduced net loss per share by $ 0.15 in 2021 . Accounting for the Royalty Pharma Royalty Purchase Agreements We periodically assess the amount and timing of expected royalty payments using a combination of internal projections and forecasts from external sources. To the extent such payments are greater or less than our initial estimates or the timing of such payments is materially different than its original estimates, we will prospectively adjust the amortization of the RP OM Liability and 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, most of which are not within our control. The RP OM Liability and RP Aficamten Liability are recognized using significant unobservable inputs. These inputs are derived using internal management estimates developed based on third party data, including competitor sales data, and reflect management’s judgements, current market conditions surrounding competing products, and forecasts. The significant unobservable inputs include the estimated patient population, estimated selling price, estimated peak sales and sales ramp, the expected term of the royalty stream, timing of the expected launch and its impact on the royalty rate as well as the overall probability of success. A significant change in unobservable inputs could result in a material increase or decrease to the effective interest rate of the RP OM Liability and RP Aficamten Liability. 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): 2022 2021 RP Aficamten Liability RP OM Liability RP OM Liability Beginning balance, January 1 $ — $ 179,072 $ 166,068 Initial carrying value 89,571 — — Interest accretion 2,286 4,278 2,795 Amortization of issuance costs — 28 27 Ending balance, March 31 91,857 183,378 168,890 As of March 31, 2022, the fair value of the liabilities related to the sale of future royalties to RPFT and RPI ICAV are consistent with its carrying value of $ 91.8 million and $ 183.4 million, respectively, and is based on our current estimates of future royalties expected to be paid to RPF T and RPI ICAV under the RP OM RPA and RP Aficamten RPA, respectively, as defined above, over the life of the arrangement, which are considered Level 3 inputs. We recognized $ 6.6 million and $ 2.8 million in non-cash interest expense for the three months ended March 31, 2022 and 2021 , respectively, related to the RP Aficamten RPA and the RP OM RPA.

Debt

Debt	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Debt	Note 7 — Debt Silicon Valley Bank and Oxford Finance Term Loans Prior to January 7, 2022, we maintained a loan and security agreement dated as of October 19, 2015, as amended (the “Term Loan Agreement”), with Silicon Valley Bank and Oxford Finance LLC (“Oxford”) (the “Lenders”). Both borrowings under the Term Loan Agreement were subject to interest at an annual rate equal to the greater of (a) 8.05 % or (b) the sum of 6.81 % plus the 30-day U.S. LIBOR rate . The borrowing under the Term Loan Agreement was repayable in monthly interest-only payments through December 31, 2020. The interest-only period was automatically extended until July 1, 2021 as a result of the Company’s initiation of a Phase 2 trial for aficamten in oHCM and was extended through December 31, 2021 as a result of the achievement of positive results in GALACTIC-HF, the trial of omecamtiv mecarbil in chronic heart failure as announced on October 8, 2020. The ultimate interest-only period was to be followed by equal monthly payments of principal and interest to the maturity date in December 2023 . We were required to make a final payment upon loan maturity of 6.00 % of the notes payable, which we accreted over the life of the Term Loan Agreement. Our obligations under the Term Loan Agreement were secured by substantially all our current and future assets, other than our intellectual property. The Term Loan Agreement was terminated and all amounts thereunder repaid in connection to our entry into that certain Development Funding Loan Agreement, dated January 7, 2022 (the “RP Loan Agreement”), between us and Royalty Pharma Development Funding, LLC (“RPDF”), as further described below. Amounts outstanding under the Term Loan Agreement were classified as non-current in our condensed consolidated balance sheet as of December 31, 2021, because short-term obligations expected to be refinanced on a long-term basis are not expected to require the use of working capital during the ensuing fiscal year. As a result of the termination of the Term Loan Agreement and the repayment to the Lenders, during the three months ended March 31, 2022 , we recorded $ 2.7 million in loss on debt extinguishment in the condensed consolidated statements of operations and comprehensive loss, consisting of the premium on debt repayments and the write-off of the remaining term loan fees and debt issuance costs. Interest expense for the Term Loan Agreement was $ 1.2 million for the three months ended March 31, 2021. Convertible Notes On November 13, 2019, the Company issued $ 138.0 million aggregate principal amount of 4.0 % convertible senior notes due 2026 (the “2026 Notes”). The 2026 Notes are unsecured obligations and bear interest at an annual rate of 4.0 % per year, payable semi-annually on May 15 and December 15 of each year, beginning May 15, 2020 . The 2026 Notes are governed by an indenture between the Company and U.S. Bank National Association, as trustee. The 2026 Notes will mature on November 15, 2026 , unless earlier repurchased or redeemed by the Company or converted at the option of the holders. The Company may redeem the 2026 Notes prior to the maturity date but is not required to and no sinking fund is provided for the 2026 Notes. The 2026 Notes may be converted, under certain circumstances as described below, based on an initial conversion rate of 94.7811 shares of common stock per $ 1,000 principal amount (which represents an initial conversion price of $ 10.55 per share). The conversion rate for the 2026 Notes will be subject to adjustment upon the occurrence of certain specified events. In addition, upon the occurrence of a make-whole fundamental change (as defined in the indenture), the Company 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 Company received approximately $ 133.9 million in net proceeds, after deducting the initial purchasers’ discount, from the issuance of the 2026 Notes. The 2026 Notes may be converted at the option of the holder under any of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2020 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 127.5 % of the last reported sale price of the Company’s common stock on November 7, 2019; (2) during the 5 consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $ 1,000 principal amount of 2026 Notes for each trading day of the measurement period was less than 98 % of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; (4) if the Company calls the 2026 Notes for redemption; and (5) at any time from, and including, July 15, 2026 until the close of business on the scheduled trading day immediately before the maturity date, November 15, 2026. The Company will settle conversions by paying or delivering, as applicable, cash, shares of the Company’s common stock, or a combination of cash and shares of the Company’s common stock, at the Company’s election, based on the applicable conversion rate. The 2026 Notes will be redeemable, in whole or in part, at the Company’s option at any time, and from time to time, on or after November 20, 2023 and, in the case of any partial redemption, on or before the 60th scheduled trading day before the maturity date, at a cash redemption price equal to the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date but only if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price on (1) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (2) the trading day immediately before the date the Company sends such notice. If a “fundamental change” (as defined in the indenture) occurs, then, subject to certain exceptions, holders may require the Company to repurchase their 2026 Notes at a cash repurchase price equal to the principal amount of the 2026 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. As discussed in Note 1, effective January 1, 2022, the Company adopted ASU 2020-06 using the modified retrospective method and, as a result, it is no longer required to separately account for the liability and equity components of the 2026 Notes, and, instead, account for the 2026 Notes wholly as debt. The following table presents the total amo unt of interest cost recognized relating to the 2026 Notes (in thousands): Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Contractual interest expense $ 1,380 $ 1,380 Amortization of debt discount — 1,371 Amortization of debt issuance costs 145 14 Total interest expense recognized $ 1,525 $ 2,765 The effective interest rate of the 2026 Notes was 4.6 % for the period ended March 31, 2022. As o f March 31, 2022, the unamortized debt issuance cost for the 2026 Notes was $ 3.5 million and will be amortized over approximately 4.7 years. If the 2026 Notes were to be converted on March 31, 2022, the holders of the 2026 Notes would receive common shares of 16.7 million with an aggregate value of $ 613.8 million based on the Company’s closing stock price of $ 36.81 as of March 31, 2022. The if-converted value of the 2026 Notes exceeded its principal amount by $ 475.8 million as of March 31, 2022. Future minimum payments under the 2026 Notes are (in thousands): Years ending December 31: 2022 remainder $ 5,520 2023 5,520 2024 5,520 2025 5,520 2026 5,520 Thereafter 138,000 Future minimum payments 165,600 Less: Interest ( 27,600 ) The 2026 Notes, principal amount 138,000 Less: Debt costs on the 2026 Notes ( 3,489 ) Net carrying amount of the 2026 Notes $ 134,511 As of March 31, 2022, the estimated fair value of our convertible notes was $ 489.8 million and was based upon observable, Level 2 inputs, including pricing information from recent trades of the convertible notes. Capped Call Transactions In connection with the offering of the 2026 Notes, the Company entered into privately-negotiated capped call transactions with one of the underwriters in the offering or its affiliate. The Company used approximately $ 13.4 million of the net proceeds from the offering of the 2026 Notes to pay the cost of the capped call transactions. The capped call transactions are expected generally to reduce potential dilution to the Company’s common stock upon any conversion of the 2026 Notes and/or offset any cash payments the Company is required to make in excess of the principal amount of converted 2026 Notes, as the case may be, in the event that the market value per share of the Company’s common stock, as measured under the terms of the capped call transactions at the time of exercise, is greater than the strike price of the capped call transactions (which initially corresponds to the initial conversion price of the 2026 Notes, and is subject to certain adjustments), with such reduction and/or offset subject to a cap initially equal to approximately $ 14.07 per share (which represents a premium of approximately 70 % over the last reported sale price of the Company’s common stock on November 7, 2019), subject to certain adjustments. The capped call transactions are separate transactions, entered into by the Company and are not part of the terms of the 2026 Notes. Given that the transactions meet certain accounting criteria, the convertible note capped call transactions are recorded in stockholders’ equity, and they are not accounted for as derivatives and are not remeasured each reporting period. As of March 31, 2022 , the Company had not purchased any shares under the convertible note capped call transactions.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Stockholders' Equity	Note 8 — Stockholders’ Equity Equity Incentive Plan Our Amended and Restated 2004 Equity Incentive Plan (the “2004 Plan”) provides for us to grant incentive stock options, nonstatutory 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 . In May 2019, our stockholders approved an amendment to the 2004 Plan to increase the number of authorized shares reserved for issuance under the 2004 Plan by 4.1 million shares. In May 2020, our board of directors approved an amendment to the 2004 Plan to increase the number of authorized shares reserved for issuance under the 2004 Plan by 0.8 million shares for inducement grants to new employees. In May 2021, our stockholders approved an amendment to the 2004 Plan to increase the number of authorized shares reserved for issuance under the 2004 Plan by 5.2 million shares to 21.5 million shares (excluding an additional 0.8 million then authorized for issuance as inducement grants to new employees). In August 2021, the Company’s board of directors approved another amendment to the 2004 plan and increased the number of shares reserved for issuance for inducement grants to new employees from the 0.8 million to 1.9 million. We started granting inducement grants in September 2020. As of March 31, 2022, the total authorized shares under the 2004 Plan of 3.0 million were available for grant. Performance Stock Units In May 2021, the Compensation and Talent Committee of the Company’s Board of Directors (“the Compensation Committee”) granted a total of 375,000 Performance Stock Units (“PSUs”) to certain employees with a weighted average grant date fair value of $ 25.32 per unit. 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 PSUs consist of two equal tranches with 50 % of each tranche vesting upon achieving certain performance criteria and 50 % vesting at the one-year anniversary of such achievement provided the recipient has been continuously employed by the Company. The first tranche vests upon certification by the Compensation Committee that the NDA for omecamtiv mecarbil has been filed and accepted by the FDA and the second tranche vests upon certification by the Compensation Committee that the FDA approval of the NDA is with an approved label that is consistent with the expectations underlying the Company’s commercial launch plans for omecamtiv mecarbil in effect immediately prior to such approval. As the FDA accepted our NDA for omecamtiv mecarbil subsequent to the year ended 2021, it resulted in a change of estimate of the probability of meeting the performance conditions for the PSU grants during the fourth quarter of 2021. The previous estimate was based on assumptions that were the best available information at the time. The change of estimate resulted in a cancellation of 91,250 PSUs and decrease of $ 0.5 million in stock-based compensation expense for the year ended December 31, 2021. During the three months ended March 31, 2022 , the performance target for the first tranche of PSUs was met. As a result, the Company recognized expense of $ 0.3 million for the first tranche of PSUs. No expense has been recognized for the second tranche to date. As of March 31, 2022 , there was $ 0.5 million unamortized stock-based compensation which may vest and recognized with respect to the achievement of the performance goals and service period. The Company will assess the likelihood of achieving the performance conditions quarterly and the expense recognized will be adjusted accordingly . Warrants As of March 31, 2022 we had outstanding warrants issued pursuant to the Term Loan Agreement with a weighted average exercise price of $ 9.12 per share to purchase 47,772 shares of our common stock.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 9 — Commitments and Contingencies Operating Leases In May 2021, we amended the lease agreement for buildings 250, 256 and 280 East Grand Avenue, South San Francisco, California for our existing facilities and extended the lease term until June 30, 2022 , which was accounted for as a lease modification in accordance with Topic 842. Pursuant to such guidance, the Company remeasured the modified lease using the revised term as of the modification date. Adjustments were made to reflect the remeasured liability with the offset to the right-of-use asset. The lease includes rental payments and payment of certain operating expenses. Under the lease terms, we have minimum rental fee payment obligations of $ 0.5 million per month through the remaining term. During the fourth quarter of 2021, we officially relocated from our existing headquarters located at 250, 256, and 280 East Grand Avenue, South San Francisco to our new facilities at Oyster Point. As a result of the relocation, we considered ceasing use of the existing headquarters, which triggered an impairment assessment. No expense was recognized for the first quarter of 2022 due to the impairment that was recorded in 2021. We are subject to the fixed rental fee payments for the existing headquarters through the remaining term until June 2022. As of March 31, 2022, the remaining lease term is 0.3 years and the discount rate used to determine the operating lease liability was 6.8 % for buildings 250, 256 and 280 East Grand Avenue, South San Francisco, California. In July 2019, we entered into a lease agreement for approximately 234,892 square feet of office and laboratory space at a facility located in South San Francisco, California and in May 2020, January 2021 and November 2021, we entered into first, second and third amendments to the lease (collectively the “Oyster Point Lease”). The Oyster Point Lease commenced on March 31, 2021 and upon commencement, we recognized a right-of-use asset of $ 77.9 million, a short-term lease liability of $ 3.7 million and a long-term lease liability of $ 85.3 million. The long-term lease liability includes $ 11.1 million of tenant improvement reimbursements as of March 31, 2021. The Oyster Point Lease had an initial expiration date of September 30, 2033 and we have two consecutive five-year options to extend the lease. The options to extend the lease term were not included as part of the right-of-use asset or lease liability as the exercise of the options were not reasonably assured at the inception of the lease. During the third quarter of 2021, we amended the lease payment schedule and will be required to start making rent payments in January 2022. The lease term is extended until October 31, 2033. The amendment was accounted for as a lease modification in accordance with Topic 842. As of March 31, 2022, the remaining lease term of the Oyster Point Lease is 11.6 years and the discount rate used to determine the related lease liability was 10.1 % . We paid a total security deposit of $ 5.1 million in December 2019 and December 2020. The landlord has provided a tenant improvement allowance of $ 43.6 million in aggregate for costs relating to the initial design and construction of the improvements. As of March 31, 2022, the total commitment of undiscounted lease payments for the Oyster Point Lease was $ 227.4 million . Cash paid for amounts included in the measurement of operating lease liabilities for the three months ended March 31, 2022 and 2021 was $ 7.2 million and $ 1.1 million , respectively, and was included in net cas h used in operating activities in our condensed consolidated statements of cash flows. Finance Leases During the third quarter of 2021, we entered into a master lease agreement for laboratory equipment leases that commenced in the fourth quarter of 2021. The leases have an initial term of 3 years and are expected to commence through the second quarter of 2022. The master lease agreement provides a purchase option with a bargain purchase price, which we expect to exercise at the end of the term. The Company classified the leases as finance leases. Finance leases are accounted for on the condensed consolidated balance sheets with right-of-use assets and lease liabilities recognized in property and equipment, other current liabilities, and other non-current liabilities, respectively. The finance lease cost is recognized as a combination of the amortization expense for the right-of-use assets calculated on a straight-line basis over the five-year estimated useful life for laboratory equipment and interest expense for the outstanding lease liabilities using the determined discount rates. As of March 31, 2022 , we have recognized finance lease right-of-use assets of $ 2.4 million, short-term finance lease liabilities of $ 0.9 million, and long-term finance lease liabilities of $ 1.4 million. As of March 31, 2022, the weighted average remaining lease term for the finance leases is 4.7 years and the weighted average discount rate used to determine the finance lease liabilities is 9.47 % . The cash paid for amounts included in the measurement of finance lease liabilities for the three months ended March 31, 2022 was $ 0.1 million and was included in net cas h provided by fin ancing activities in our condensed consolidated statements of cash flows. The undiscounted future non-cancellable lease payments under all our lease agreements as of March 31, 2022 is as follows (in thousands): Years ending December 31: Operating Leases Finance Leases 2022 remainder $ 11,052 $ 713 2023 17,060 843 2024 17,620 843 2025 18,199 165 2026 18,799 — Thereafter 146,193 — Total undiscounted future lease payments 228,923 2,564 Less: Present value adjustments ( 102,410 ) ( 282 ) Total lease liability $ 126,513 $ 2,282 The lease obligations for the finance leases that have not yet commenced as of March 31, 2022, is approximately $ 0.8 million , which are not included in the table above. These leases will commence in the second quarter of 2022 and expire in 2025. Rent expenses for operating leases and finance leases were $ 5.6 million and $ 1.5 million for the three months ended March 31, 2022 and 2021 , respectively.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Note 10 — Subsequent Events On April 25, 2022, the Mavacamten Royalty was extinguished pursuant to a letter agreement between the Company, RTW Investments ICAV, and MyoKardia, Inc. We are evaluating the impact of this termination on our financial statements.

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	Cytokinetics, Incorporated (the “Company”, “we” or “our”) 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 $ 1,286.5 million since inception and there can be no assurance that we will attain profitability. The Company anticipates that it will have operating losses and net cash outflows in future periods. We are subject to risks common to late stage biopharmaceutical companies including, but not limited to, development of new drug candidates, dependence on key personnel, and the ability to obtain additional capital as needed to fund our future plans. Our liquidity will be impaired if sufficient additional capital is not available on terms acceptable to us. To date, we have funded operations primarily through sales of our common stock, contract payments under our collaboration agreements, sales of future revenues and royalties, debt financing arrangements, government grants and interest income. Until we achieve profitable operations, we intend to continue to fund operations through payments from strategic collaborations, additional sales of equity securities, grants and debt financings. We have never generated revenues from commercial sales of our drugs and may not have drugs to market for at least several years, if ever. Our success is dependent on our ability to enter into new strategic collaborations and/or raise additional capital and to successfully develop and market one or more of our drug candidates. We cannot be certain that sufficient funds will be available from such a financing or through a collaborator when required or on satisfactory terms. Additionally, there can be no assurance that our drug candidates will be accepted in the marketplace or that any future products can be developed or manufactured at an acceptable cost. These factors could have a material adverse effect on our future financial results, financial position and cash flows. Based on the current status of our research and development activities, we believe that our existing cash, cash equivalents and investments will be sufficient to fund cash requirements for at least the next 12 months from the filing date 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 subsidiary. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“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, 2021 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, 2021 , 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 us 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 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt-Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging-Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). Under ASU 2020-06 the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives under Topic 815, Derivatives and Hedging, or that do not result in substantial premiums accounted for as paid-in capital. Consequently, a convertible debt instrument will be accounted for as a single liability measured at its amortized cost and convertible preferred stock will be accounted for as a single equity instrument measured at its historical cost, as long as no other features require bifurcation and recognition as derivatives. By removing those separation models, the interest rate of convertible debt instruments typically will be closer to the coupon interest rate. ASU 2020-06 also provides for certain disclosures with regard to convertible instruments and associated fair values. ASU 2020-06 is effective for annual reporting periods after December 15, 2021 and interim periods within those annual periods and early adoption is permitted. ASU 2020-06 provides companies with the option to adopt the new standard using either the full retrospective or modified retrospective method. We adopted this new guidance using the modified retrospective method as of January 1, 2022, with respect to our convertible senior notes due 2026 (the “2026 Notes”). The cumulative effect of initially applying the new standard was recognized as an adjustment to accumulated deficit. The following table summarizes the adjustments made to our condensed consolidated balance sheet as of January 1, 2022, upon adoption of the new standard: Balance sheet account description Ending Balance ASU 2020-06 Adjustments Beginning Balance Convertible notes, net $ 95,471 $ 38,895 $ 134,366 Additional paid-in capital 1,452,268 ( 49,476 ) 1,402,792 Accumulated deficit ( 1,207,620 ) 10,581 ( 1,197,039 ) The adoption of this new guidance resulted in an increase in the carrying value of the 2026 Notes to reflect the full principal amount of the convertible notes outstanding, net of issuance costs, a decrease in additional paid-in capital to remove the equity component separately recorded for the conversion feature associated with the convertible notes, a cumulative-effect adjustment to the beginning balance of our accumulated deficit as of January 1, 2022 to reverse the accretion of discount that resulted from the bifurcation of the equity component of the 2026 Notes, and a reversal of the related deferred tax liability of $ 8.3 million with a corresponding increase in our deferred tax asset valuation allowance. The adoption of this new guidance has reduced non-cash interest expense for the year ending December 31, 2022 and will continue to do so until the 2026 Notes have been settled. The remaining debt issuance costs will continue to be amortized over the term of the notes. We have recognized $ 1.5 million of interest expense of the 2026 Notes for the three months ended March 31, 2022, which is $ 1.4 million less than under the previous accounting standards. Without the adoption of ASU 2020-06, our reported net loss and net loss per share would increase by $ 1.4 million and $ 0.02 per share, respectively.

Organization and Significant _3

Organization and Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Adjustments made to Condensed Consolidated Balance Sheet upon Adoption of New Standard	The following table summarizes the adjustments made to our condensed consolidated balance sheet as of January 1, 2022, upon adoption of the new standard: Balance sheet account description Ending Balance ASU 2020-06 Adjustments Beginning Balance Convertible notes, net $ 95,471 $ 38,895 $ 134,366 Additional paid-in capital 1,452,268 ( 49,476 ) 1,402,792 Accumulated deficit ( 1,207,620 ) 10,581 ( 1,197,039 )

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2022
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): March 31, 2022 March 31, 2021 Options to purchase common stock 10,855 9,508 Warrants to purchase common stock 47 48 Restricted stock and performance units 1,520 1,154 Shares issuable related to the ESPP 31 45 Shares issuable upon conversion of convertible notes 16,675 16,675 Total shares 29,128 27,430

Research and Development Arra_2

Research and Development Arrangements (Tables)	3 Months Ended
	Mar. 31, 2022
Research And Development [Abstract]
Schedule of Allocated Consideration	The Ji Xing OM License Agreement, as defined below, and the sales of common stock to the RTW Investors, as defined below, in December 2021, as described below, (together the “2021 RTW Transactions”) were entered into with parties that were at the time of our entry into the 2021 RTW Transactions affiliated and in contemplation of one another and, accordingly, we have assessed the accounting for these transactions in the aggregate. Unconstrained arrangement consideration under the 2021 RTW Transactions totaled $ 70.0 million and was allocated in accordance with ASC 820 and ASC 606 as follows (in thousands): Allocated Units of Accounting: License and collaboration $ 54,856 Common stock (fair value) 15,144 Total consideration $ 70,000 The 2020 RTW Transactions were entered into with parties that were at the time of our entry into the 2020 RTW Transactions affiliated and in contemplation of one another and, accordingly, we have assessed the accounting for these transactions in the aggregate. We concluded that there were three units of accounting in the 2020 RTW Transactions as further described below. The Company allocated the total consideration in accordance with ASC 820, Fair Value Measurement, and ASC 606, Revenue from Contracts with Customers, as follows (in thousands): Allocated Units of Accounting: License and collaboration (residual) $ 36,501 Royalty (fair value) 87,000 Common stock (fair value) 36,499 Total consideration $ 160,000

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
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): March 31, 2022 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 65,445 $ — $ — $ 65,445 U.S. Treasury securities Level 1 244,527 — ( 1,330 ) 243,197 U.S. and non-U.S. government agency bonds Level 2 24,892 — ( 162 ) 24,730 Commercial paper Level 2 188,023 — ( 264 ) 187,759 U.S. and non-U.S. corporate obligations Level 2 163,234 — ( 1,833 ) 161,401 $ 686,121 $ — $ ( 3,589 ) $ 682,532 December 31, 2021 Fair Value Amortized Unrealized Unrealized Fair Money market funds Level 1 $ 115,937 $ — $ — $ 115,937 U.S. Treasury securities Level 1 133,498 1 ( 268 ) 133,231 U.S. and non-U.S. government agency bonds Level 2 33,489 — ( 53 ) 33,436 Commercial paper Level 2 169,622 6 ( 19 ) 169,609 U.S. and non-U.S. corporate obligations Level 2 175,282 — ( 536 ) 174,746 $ 627,828 $ 7 $ ( 876 ) $ 626,959 The available-for-sale securities in our condensed consolidated balance sheet are as follows (in thousands): March 31, 2022 December 31, 2021 Cash equivalents $ 111,897 $ 115,937 Short-term investments 493,552 358,972 Long-term investments 77,083 152,050 $ 682,532 $ 626,959

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Accrued Liabilities	Accrued liabilities were as follows (in thousands): March 31, 2022 December 31, 2021 Accrued liabilities: Clinical and preclinical costs $ 14,790 $ 13,872 Compensation related 9,824 14,930 Other accrued expenses 4,863 5,568 Total accrued liabilities $ 29,477 $ 34,370

Agreements with Royalty Pharma

Agreements with Royalty Pharma (Tables)	3 Months Ended
	Mar. 31, 2022
Agreements With Royalty Pharma [Abstract]
Schedule of Total Consideration	The total consideration was allocated as follows (in thousands): Fair Value Proceeds Allocation Units of Accounting: Revenue Participation Right Purchase Agreement $ 69,498 $ 100,000 $ 89,571 Development Funding Loan Agreement 46,887 50,000 60,429 Total consideration $ 116,385 $ 150,000 $ 150,000
Schedule of Future Minimum Payments under Term Loan Agreement	Future minimum payments under the RP Loan Agreement are (in thousands): Years ending December 31: 2022 remainder $ — 2023 1,440 2024 10,080 2025 11,520 2026 11,520 Thereafter 60,480 Future minimum payments 95,040 Less: Unamortized interest and loan costs ( 33,875 ) Term Loan, net $ 61,165
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): 2022 2021 RP Aficamten Liability RP OM Liability RP OM Liability Beginning balance, January 1 $ — $ 179,072 $ 166,068 Initial carrying value 89,571 — — Interest accretion 2,286 4,278 2,795 Amortization of issuance costs — 28 27 Ending balance, March 31 91,857 183,378 168,890

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Schedule of Interest Cost Relating to 2026 Notes	The following table presents the total amo unt of interest cost recognized relating to the 2026 Notes (in thousands): Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Contractual interest expense $ 1,380 $ 1,380 Amortization of debt discount — 1,371 Amortization of debt issuance costs 145 14 Total interest expense recognized $ 1,525 $ 2,765
Schedule of Maturities of 2026 Notes	Future minimum payments under the 2026 Notes are (in thousands): Years ending December 31: 2022 remainder $ 5,520 2023 5,520 2024 5,520 2025 5,520 2026 5,520 Thereafter 138,000 Future minimum payments 165,600 Less: Interest ( 27,600 ) The 2026 Notes, principal amount 138,000 Less: Debt costs on the 2026 Notes ( 3,489 ) Net carrying amount of the 2026 Notes $ 134,511

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Schedule of Undiscounted Future Non-cancellable Lease Payments under the Lease Agreements	The undiscounted future non-cancellable lease payments under all our lease agreements as of March 31, 2022 is as follows (in thousands): Years ending December 31: Operating Leases Finance Leases 2022 remainder $ 11,052 $ 713 2023 17,060 843 2024 17,620 843 2025 18,199 165 2026 18,799 — Thereafter 146,193 — Total undiscounted future lease payments 228,923 2,564 Less: Present value adjustments ( 102,410 ) ( 282 ) Total lease liability $ 126,513 $ 2,282

Organization and Significant _4

Organization and Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Jan. 01, 2022	Dec. 31, 2021
Cumulative Effect Period of Adoption Adjustment [Line Items]
Accumulated deficit incurred	$ (1,286,484)		$ (1,197,039)	$ (1,207,620)
Cash requirements term	12 months
Interest expense	$ 2,746	$ 3,988
ASU 2020-06 [Member]
Cumulative Effect Period of Adoption Adjustment [Line Items]
Accumulated deficit incurred			10,581
Deferred tax liability reversal			$ 8,300
Increase in net loss	$ 1,400
Increase in net loss per share	$ 0.02
ASU 2020-06 [Member] | 2026 Notes [Member]
Cumulative Effect Period of Adoption Adjustment [Line Items]
Interest expense	$ 1,500
Decrease in interest expense	$ 1,400

Organization and Significant _5

Organization and Significant Accounting Policies - Summary of Adjustments made to Condensed Consolidated Balance Sheet upon Adoption of New Standard (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Jan. 01, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Convertible notes, net		$ 134,366	$ 95,471
Additional paid-in capital		1,402,792	1,452,268
Accumulated deficit	$ (1,286,484)	(1,197,039)	$ (1,207,620)
ASU 2020-06 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Convertible notes, net		38,895
Additional paid-in capital		(49,476)
Accumulated deficit		$ 10,581

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	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	29,128	27,430
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	10,855	9,508
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	47	48
Restricted Stock and Performance Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	1,520	1,154
Shares Issuable Related to the ESSP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	31	45
Shares Issuable Upon Conversion of Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	16,675	16,675

Research and Development Arra_3

Research and Development Arrangements - Additional Information (Details) - USD ($)	Dec. 20, 2021	Jul. 14, 2020	Apr. 23, 2020	Dec. 31, 2021	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues					$ 1,148,000		$ 6,548,000
Accounts receivable				$ 51,819,000	6,056,000			$ 51,819,000
Amount received as milestone payment						$ 5,000,000
Amount reclassed to accounts receivable as milestone payment					5,000,000
Long-term deferred revenue				87,000,000	87,000,000			87,000,000
Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Nonrefundable payment obligation	$ 50,000,000
Amount received as milestone payment	$ 50,000,000
Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received		$ 25,000,000
Royalty Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sale of interest in future royalties		$ 85,000,000
Fair Value of Royalty									$ 87,000,000
Long-term deferred revenue					87,000,000
Common Stock Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock upon private placement, shares	511,182	2,000,000
Shares Issued, price per share	$ 39.125	$ 25
Net proceeds of issuance of common stock	$ 20,000,000	$ 50,000,000
Common stock purchase agreement date	Dec. 20, 2021	Jul. 14, 2020
Excess amount paid over the fair value of the shares	$ 4,900,000	$ 13,500,000
Fair value of common stock	15,100,000	36,500,000
Maximum [Member] | Ji Xing Omecamtiv Mecarbil License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential additional payments receivable	330,000,000
Maximum [Member] | Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential additional payments receivable		200,000,000
Maximum [Member] | Funding Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone receivable		$ 90,000,000
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
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 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues								54,900,000
License [Member] | Ji Xing Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues								0	$ 36,500,000
Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues					1,148,000		6,548,000
RTW [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Allocation of unconstrained arrangement consideration				70,000,000				70,000,000
Amgen | Research And Development Milestone Grant And Other Revenues Net
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues					0		0
Astellas [Member] | Accounting Standards Update 2014-09
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable				$ 1,800,000	1,100,000			$ 1,800,000
Astellas [Member] | Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues					$ 1,100,000		$ 1,700,000

Research and Development Arra_4

Research and Development Arrangements - Schedule of Allocated Consideration (Details) - USD ($) $ in Thousands	Jul. 14, 2020	Dec. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Total revenues			$ 1,148	$ 6,548
RTW [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Total consideration		$ 70,000			$ 70,000
RTW [Member] | Collaborative Arrangement [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Total consideration	$ 160,000
RTW [Member] | Common Stock [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Fair value of common stock		15,144
RTW [Member] | Common Stock [Member] | Collaborative Arrangement [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Fair value of common stock	36,499
RTW [Member] | License and Collaboration [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Total revenues		$ 54,856
RTW [Member] | License and Collaboration [Member] | Collaborative Arrangement [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Total revenues	36,501
RTW [Member] | Royalty [Member] | Collaborative Arrangement [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Fair Value of Royalty	$ 87,000

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) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	$ 682,532	$ 626,959
Long-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	77,083	152,050
Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	111,897	115,937
Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	493,552	358,972
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	686,121	627,828
Unrealized Gains	0	7
Unrealized Losses	(3,589)	(876)
Fair Value	682,532	626,959
Money Market Funds [Member] | Fair Value Measurements Using Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	65,445	115,937
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	65,445	115,937
U.S. Treasury Securities [Member] | Fair Value Measurements Using Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	244,527	133,498
Unrealized Gains	0	1
Unrealized Losses	(1,330)	(268)
Fair Value	243,197	133,231
U.S. and Non-U.S. Government Agency Bonds [Member] | Fair Value Measurements Using Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	24,892	33,489
Unrealized Gains	0	0
Unrealized Losses	(162)	(53)
Fair Value	24,730	33,436
Commercial Paper [Member] | Fair Value Measurements Using Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	188,023	169,622
Unrealized Gains	0	6
Unrealized Losses	(264)	(19)
Fair Value	187,759	169,609
U.S. and Non-U.S. Corporate Obligations [Member] | Fair Value Measurements Using Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	163,234	175,282
Unrealized Gains	0	0
Unrealized Losses	(1,833)	(536)
Fair Value	$ 161,401	$ 174,746

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Interest Income	$ 400,000	$ 300,000
Credit losses on debt securities	0	$ 0
Fair value of liabilities transferred from level 1 to level 2	0
Fair value of liabilities transferred from level 2 to level 1	0
Fair value of liabilities transferred into level 3	0
Fair value of liabilities transferred from level 3	$ 0

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued liabilities:
Clinical and preclinical costs	$ 14,790	$ 13,872
Compensation related	9,824	14,930
Other accrued expenses	4,863	5,568
Total accrued liabilities	$ 29,477	$ 34,370

Agreements with Royalty Pharm_2

Agreements with Royalty Pharma - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 07, 2022	Feb. 28, 2017	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Nov. 30, 2022
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Arrangement consideration of debt transaction	$ 150,000
Interest expense			$ 2,746	$ 3,988
Liabilities			739,992		$ 597,456
Liabilities related to revenue participation right purchase agreements, net			275,235		$ 179,072
RP Aficamten RPA, RPI ICAV [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Liabilities related to revenue participation right purchase agreements, net			183,400
RP Loan Agreement [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt			61,165
RP OM RPA [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Non-cash interest expense recognized				2,800
RPI Finance Trust [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Liabilities related to revenue participation right purchase agreements, net			91,800
RP Aficamten RPA [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Non-cash interest expense recognized			$ 6,600
2022 Royalty Pharma Transactions [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Milestone payment	50,000
2022 Royalty Pharma Transactions [Member] | RP Aficamten RPA, RPI ICAV [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Upfront payment	50,000
Purchased rights to certain revenue streams from net sales in consideration payment	$ 50,000
Percentage of net sales payable	4.50%
4.5% of net revenue to be receivable from annual worldwide net sales	$ 1,000,000
Percentage of net sales payable for excess of annual worldwide net sales	3.50%
3.5% of net sales payable for excess of annual worldwide net sales	$ 1,000,000
Imputed rate interest on unamortized portion of liability			11.70%
2022 Royalty Pharma Transactions [Member] | RP Aficamten RPA, RPI ICAV [Member] | oHCM [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Amount payable 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]
Amount payable 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 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
Long term debt			$ 61,200
Term loan, maturity year	10 years
Debt instrument effective interest rate	7.65%
Repayable loan percentage to principal amount Including interest and other fees	190.00%
Applicable prepayment charges on term loan	$ 34,600
Debt Instrument Face Amount	25,000
Interest expense			$ 1,200
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
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
2022 Royalty Pharma Transactions [Member] | RP Loan Agreement [Member] | Term Loan Tranche 5 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt	100,000
2022 Royalty Pharma Transactions [Member] | RP Loan Agreement [Member] | Term Loan Tranche 4 [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Long term debt	$ 75,000
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
Imputed rate of interest on unamortized liability			10.00%		10.00%
Liabilities related to revenue participation right purchase agreements, net			$ 183,378	$ 168,890	$ 179,072	$ 166,068
Royalty Purchase Finance Trust Agreement [Member] | Change in Accounting Estimate [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Imputed rate of interest on unamortized liability					10.00%	15.00%
Non-cash interest expense recognized					$ 12,900	$ 22,700
Reduction in net loss					$ 11,500
Reduction in net loss per share					$ 0.15
Royalty Purchase Finance Trust Agreement [Member] | Maximum [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Additional percent of royalty on net sale		1.00%
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%
Royalty Purchase Finance Trust Agreement [Member] | Forecast [Member] | Minimum [Member]
Liabilities Related to Revenue Participation Right Purchase Agreements [Line Items]
Percent of royalty on net sale							4.90%

Agreements with Royalty Pharm_3

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

Agreements with Royalty Pharm_4

Agreements with Royalty Pharma - Schedule of Future Minimum Payments under Term Loan Agreement (Detail) - RP Loan Agreement [Member] $ in Thousands	Mar. 31, 2022USD ($)
Debt Instrument [Line Items]
2023	$ 1,440
2024	10,080
2025	11,520
2026	11,520
Thereafter	60,480
Future minimum payments	95,040
Less: Unamortized interest and loan costs	(33,875)
Term Loan, net	$ 61,165

Agreements with Royalty Pharm_5

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		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Royalty Liability [Line Items]
Liabilities related to revenue participation right purchase agreements, net beginning balance	$ 179,072
Liabilities related to revenue participation right purchase agreements, net ending balance	275,235		$ 179,072
RPOM Liability
Royalty Liability [Line Items]
Liabilities related to revenue participation right purchase agreements, net beginning balance	179,072	$ 166,068	166,068
Interest accretion	4,278	2,795
Amortization of issuance costs	28	27
Liabilities related to revenue participation right purchase agreements, net ending balance	183,378	$ 168,890	$ 179,072
RP Aficamten Liability
Royalty Liability [Line Items]
Initial carrying value	89,571
Interest accretion	2,286
Liabilities related to revenue participation right purchase agreements, net ending balance	$ 91,857

Debt - Additional Information (

Debt - Additional Information (Detail)	Nov. 13, 2019USD ($)$ / sharesshares	Nov. 07, 2019$ / shares	Mar. 31, 2022USD ($)Days$ / sharesshares	Mar. 31, 2021USD ($)
Debt Instrument [Line Items]
Interest expense			$ 2,746,000	$ 3,988,000
Convertible debt, fair value			489,800,000
Loss on extinguishment of debt			(2,693,000)	0
Purchase of capped call options associated with convertible notes			13,400,000
Cap price of capped call transactions | $ / shares		$ 14.07
Capped call premium percentage of sale price of common stock		70.00%
Oxford and Silicon Valley Bank [Member] | Term Loan Agreement [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt			$ 2,700,000
Oxford and Silicon Valley Bank [Member] | 2019 Term Loan [Member] | Term Loan Agreement [Member]
Debt Instrument [Line Items]
Interest expense				$ 1,200,000
Oxford and Silicon Valley Bank [Member] | 2019 Term Loan [Member] | Amended Loan Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, applicable interest rate for scenario 1			8.05%
Debt instrument, base interest rate for scenario 2			6.81%
Interest rate description			Both borrowings under the Term Loan Agreement were subject to interest at an annual rate equal to the greater of (a) 8.05% or (b) the sum of 6.81% plus the 30-day U.S. LIBOR rate
Oxford and Silicon Valley Bank [Member] | 2019 Term Loan [Member] | New Loan and Security Agreement [Member]
Debt Instrument [Line Items]
Loan repayment terms			The borrowing under the Term Loan Agreement was repayable in monthly interest-only payments through December 31, 2020. The interest-only period was automatically extended until July 1, 2021 as a result of the Company’s initiation of a Phase 2 trial for aficamten in oHCM and was extended through December 31, 2021 as a result of the achievement of positive results in GALACTIC-HF, the trial of omecamtiv mecarbil in chronic heart failure as announced on October 8, 2020. The ultimate interest-only period was to be followed by equal monthly payments of principal and interest to the maturity date in December 2023
Final payment fee percentage			6.00%
2026 Notes [Member]
Debt Instrument [Line Items]
Principal amount of original loan	$ 138,000,000		$ 138,000,000
Number of instalments description			payable semi-annually on May 15 and December 15 of each year, beginning May 15, 2020
Convertible notes, maturity date	Nov. 15, 2026
Convertible notes, interest rate	4.00%
Convertible notes, sinking fund	$ 0
Convertible notes, shares issued | shares	94.7811
Convertible notes, principal amount	$ 1,000
Convertible notes, initial conversion price | $ / shares	$ 10.55
Convertible notes, type of equity security issued			common stock
Net proceeds from convertible notes, net of debt discount and issuance costs	$ 133,900,000
Convertible notes, conversion description			The 2026 Notes may be converted at the option of the holder under any of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2020 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 127.5% of the last reported sale price of the Company’s common stock on November 7, 2019; (2) during the 5 consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of 2026 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; (4) if the Company calls the 2026 Notes for redemption; and (5) at any time from, and including, July 15, 2026 until the close of business on the scheduled trading day immediately before the maturity date, November 15, 2026. The Company will settle conversions by paying or delivering, as applicable, cash, shares of the Company’s common stock, or a combination of cash and shares of the Company’s common stock, at the Company’s election, based on the applicable conversion rate.
Convertible notes, redemption description			The 2026 Notes will be redeemable, in whole or in part, at the Company’s option at any time, and from time to time, on or after November 20, 2023 and, in the case of any partial redemption, on or before the 60th scheduled trading day before the maturity date, at a cash redemption price equal to the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date but only if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price on (1) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (2) the trading day immediately before the date the Company sends such notice. If a “fundamental change” (as defined in the indenture) occurs, then, subject to certain exceptions, holders may require the Company to repurchase their 2026 Notes at a cash repurchase price equal to the principal amount of the 2026 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date.
Debt instrument, unamortized debt issuance cost			$ 3,500,000
Unamortized debt discount amortization period			4 years 8 months 12 days
If-converted value in excess of principal amount			$ 475,800,000
Conversion of units | shares			16,700,000
Conversion of units			$ 613,800,000
Stock price | $ / shares			$ 36.81
2026 Notes [Member] | Liability [Member]
Debt Instrument [Line Items]
Debt instrument effective interest rate			4.60%
2026 Notes [Member] | Debt Instrument Convertible Covenant One [Member]
Debt Instrument [Line Items]
Convertible notes, percentage of conversion price			127.50%
Convertible notes, trading days | Days			20
Convertible notes, consecutive trading days | Days			30
2026 Notes [Member] | Debt Instrument Convertible Covenant Two [Member]
Debt Instrument [Line Items]
Convertible notes, percentage of last reported sale price of common stock			98.00%
Convertible notes, trading days | Days			5
Convertible notes, consecutive trading days | Days			10

Debt - Schedule of Interest Cos

Debt - Schedule of Interest Cost Relating to 2026 Notes (Detail) - 2026 Notes [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Contractual interest expense	$ 1,380	$ 1,380
Amortization of debt discount	0	1,371
Amortization of debt issuance costs	145	14
Total interest expense recognized	$ 1,525	$ 2,765

Debt - Schedule of Future Minim

Debt - Schedule of Future Minimum Payments under 2026 Notes (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Nov. 13, 2019
Debt Instrument [Line Items]
Net carrying amount of the 2026 Notes	$ 134,511	$ 95,471
2026 Notes [Member]
Debt Instrument [Line Items]
2022 remainder	5,520
2023	5,520
2024	5,520
2025	5,520
2026	5,520
Thereafter	138,000
Term Loan, net	165,600
Less: Interest	(27,600)
The 2026 Notes, principal amount	138,000		$ 138,000
Less: Debt costs on the 2026 Notes	(3,489)
Net carrying amount of the 2026 Notes	$ 134,511

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	1 Months Ended	3 Months Ended		12 Months Ended
	May 31, 2021Tranche$ / sharesshares	Mar. 31, 2022USD ($)$ / sharesshares	Dec. 31, 2021shares	Dec. 31, 2021USD ($)	Aug. 31, 2021shares	May 31, 2020shares	May 31, 2019shares
2004 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term to grant nonstatutory stock options and incentive stock options		10 years
Option grant prices as percentage of the fair market value of the common stock		100.00%
Percentage of options grant to new employees		25.00%
Number of authorized shares reserved for issuance	21,500,000
Shares available for grant		3,000,000
Increase in number of authorized shares reserved for issuance	5,200,000				1,900,000	800,000	4,100,000
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
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	375,000
Per unit weighted average grant date fair value | $ / shares	$ 25.32
Number of tranche | Tranche	2
Number of shares cancelled			91,250
Decrease in allocated share based compensation expense | $				$ 500,000
Unamortized/unrecognized stock-based compensation expense | $		$ 500,000
Performance Stock Units | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share based payment award award vesting rights percentage	50.00%
Allocated share based compensation expense | $		300,000
Performance Stock Units | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share based payment award award vesting rights percentage	50.00%
Allocated share based compensation expense | $		$ 0
Oxford and Silicon Valley Bank [Member] | New Loan and Security Agreement [Member] | 2019 Term Loan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding warrants, weighted average exercise price | $ / shares		$ 9.12
Outstanding warrants		47,772

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)ft²	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Lessee Lease Description [Line Items]
Operating lease, right-of-use assets	$ 72,646		$ 73,138
Operating lease, short-term lease liability	14,490		14,863
Operating lease, long-term lease liability	$ 112,023		$ 112,229
Finance lease, contractual lease term	3 years
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities Current
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent
Lease obligations for finance leases not yet commenced	$ 800
Rent expenses for the operating leases and finance leases	5,600	$ 1,500
Lease Agreement
Lessee Lease Description [Line Items]
Operating lease, cash paid included in net cash used in operating activities	$ 7,200	$ 1,100
Financial lease estimated life	5 years
Finance Lease, Right-of-Use Asset	$ 2,400
Short term finance lease liability	900
Long term finance lease liability	$ 1,400
Finance lease, weighted average remaining lease term	4 years 8 months 12 days
Finance lease, weighted average discount rate	9.47%
Finance lease payments	$ 100
Current Lease [Member]
Lessee Lease Description [Line Items]
Operating lease, lease expiration date	Jun. 30, 2022
Operating lease, weighted average remaining lease term	3 months 18 days
Operating lease, weighted average discount rate	6.80%
Current Lease [Member] | Minimum [Member]
Lessee Lease Description [Line Items]
Operating lease, payments monthly	$ 500
Oyster Point Lease [Member] | California [Member]
Lessee Lease Description [Line Items]
Operating lease, lease expiration date	Sep. 30, 2033
Operating lease, area of land under lease agreement | ft²	234,892
Operating lease, commencement period	2021-03
Operating lease, right-of-use assets	$ 77,900
Operating lease, short-term lease liability	3,700
Operating lease, long-term lease liability	85,300
Operating lease, tenant improvement reimbursements	$ 11,100
Operating lease, weighted average remaining lease term	11 years 7 months 6 days
Operating lease, weighted average discount rate	10.10%
Operating lease, security deposit liability				$ 5,100	$ 5,100
Operating lease agreement allowances for tenant improvements	$ 43,600
Operating lease undiscounted lease payments	$ 227,400
Operating lease, term description	we have two consecutive five-year options to extend the lease.

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Undiscounted Future Non-cancellable Lease Payments under the Lease Agreements (Detail) $ in Thousands	Mar. 31, 2022USD ($)
Leases [Abstract]
2022 remainder	$ 11,052
2023	17,060
2024	17,620
2025	18,199
2026	18,799
Thereafter	146,193
Total undiscounted future lease payments	228,923
Less: Present value adjustments	(102,410)
Total lease liability	126,513
2022 remainder	713
2023	843
2024	843
2025	165
2026	0
Thereafter	0
Total undiscounted future lease payments	2,564
Less: Present value adjustments	(282)
Total lease liability	$ 2,282