0001564590-21-042136 | 10-Q | XBRL Viewer

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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2021	Aug. 02, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	CYTK
Entity Registrant Name	CYTOKINETICS, INCORPORATED
Entity Central Index Key	0001061983
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	000-50633
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3291317
Entity Address, Address Line One	280 East Grand Avenue
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		83,512,670
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 Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 37,154	$ 82,985
Short-term investments	313,147	381,075
Accounts receivable	2,701	4,420
Prepaid expenses and other current assets	11,227	5,741
Total current assets	364,229	474,221
Long-term investments	73,672	36,954
Property and equipment, net	36,942	13,346
Operating lease right-of-use assets	83,006	2,924
Other assets	6,453	6,358
Total assets	564,302	533,803
Current liabilities:
Accounts payable	14,928	8,050
Accrued liabilities	22,394	19,315
Current portion of long-term debt	11,250	0
Short-term lease liabilities	12,190	2,785
Other current liabilities	1,004	1,049
Total current liabilities	61,766	31,199
Term loan, net	35,538	46,209
Convertible notes, net	92,348	89,504
Liability related to the sale of future royalties, net	171,790	166,068
Long-term deferred revenue	87,000	87,000
Long-term lease and other non-current liabilities	99,371	440
Total liabilities	547,813	420,420
Commitments and contingencies	0	0
Stockholders’ equity:
Preferred stock, $0.001 par value	0	0
Common stock, $0.001 par value	72	70
Additional paid-in capital	1,117,403	1,105,470
Accumulated other comprehensive (loss) income	(22)	149
Accumulated deficit	(1,100,964)	(992,306)
Total stockholders’ equity	16,489	113,383
Total liabilities and stockholders’ equity	$ 564,302	$ 533,803

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Common stock, par value	$ 0.001	$ 0.001

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Total revenues	$ 2,843	$ 3,593	$ 9,391	$ 7,418
Operating expenses:
Research and development	36,443	21,790	68,004	43,528
General and administrative	21,197	14,161	36,795	26,610
Total operating expenses	57,640	35,951	104,799	70,138
Operating loss	(54,797)	(32,358)	(95,408)	(62,720)
Interest expense	(4,073)	(3,892)	(8,061)	(7,969)
Non-cash interest expense on liability related to the sale of future royalties	(2,871)	(5,912)	(5,666)	(11,601)
Interest and other income, net	187	1,382	477	2,105
Net loss	$ (61,554)	$ (40,780)	$ (108,658)	$ (80,185)
Net loss per share — basic and diluted	$ (0.86)	$ (0.68)	$ (1.52)	$ (1.35)
Weighted-average number of shares used in computing net loss per share — basic and diluted	71,754	59,605	71,476	59,438
Other comprehensive loss:
Unrealized (loss) gain on available-for-sale securities, net	$ (72)	$ (276)	$ (171)	$ 658
Comprehensive loss	(61,626)	(41,056)	(108,829)	(79,527)
Research and Development Revenues [Member]
Revenues:
Total revenues	$ 2,843	$ 3,593	$ 9,391	$ 7,418

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2019	$ (10,937,000)	$ 59,000	$ 853,341,000	$ 679,000	$ (865,016,000)
Beginning Balance, shares at Dec. 31, 2019		59,172,124
Exercise of stock options, value	93,000	$ 0	93,000	0	0
Exercise of stock options, shares		12,165
Vesting of restricted stock units, net of taxes withheld, value	(2,255,000)	$ 0	(2,255,000)	0	0
Vesting of restricted stock units, net of taxes withheld, shares		274,563
Claims settlement under Section 16(b)	2,151,000	$ 0	2,151,000	0	0
Issuance of warrants	184,000	0	184,000	0	0
Stock-based compensation	3,524,000	0	3,524,000	0	0
Other comprehensive loss	934,000	0	0	934,000	0
Net loss	(39,405,000)	0	0	0	(39,405,000)
Ending Balance at Mar. 31, 2020	(45,711,000)	$ 59,000	857,038,000	1,613,000	(904,421,000)
Ending Balance, shares at Mar. 31, 2020		59,458,852
Beginning Balance at Dec. 31, 2019	(10,937,000)	$ 59,000	853,341,000	679,000	(865,016,000)
Beginning Balance, shares at Dec. 31, 2019		59,172,124
Net loss	(80,185,000)
Ending Balance at Jun. 30, 2020	(78,080,000)	$ 60,000	865,724,000	1,337,000	(945,201,000)
Ending Balance, shares at Jun. 30, 2020		59,942,070
Beginning Balance at Mar. 31, 2020	(45,711,000)	$ 59,000	857,038,000	1,613,000	(904,421,000)
Beginning Balance, shares at Mar. 31, 2020		59,458,852
Exercise of stock options, value	3,334,000	$ 1,000	3,333,000	0	0
Exercise of stock options, shares		396,379
Stock-based compensation	4,527,000	$ 0	4,527,000	0	0
Issuance of common stock under Employee Stock Purchase Plan	826,000	$ 0	826,000	0	0
Issuance of common stock under Employee Stock Purchase Plan		86,839
Other comprehensive loss	(276,000)	$ 0	0	(276,000)	0
Net loss	(40,780,000)	0	0	0	(40,780,000)
Ending Balance at Jun. 30, 2020	(78,080,000)	$ 60,000	865,724,000	1,337,000	(945,201,000)
Ending Balance, shares at Jun. 30, 2020		59,942,070
Beginning Balance at Dec. 31, 2020	113,383,000	$ 70,000	1,105,470,000	149,000	(992,306,000)
Beginning Balance, shares at Dec. 31, 2020		71,015,183
Exercise of stock options, value	1,272,000	$ 1,000	1,271,000	0	0
Exercise of stock options, shares		187,807
Vesting of restricted stock units, net of taxes withheld, value	(4,449,000)	$ 0	(4,449,000)	0	0
Vesting of restricted stock units, net of taxes withheld, shares		360,050
Net share settlement	(418,000)	$ 0	(418,000)	0	0
Stock-based compensation	5,261,000	0	5,261,000	0	0
Other comprehensive loss	(99,000)	0	0	(99,000)	0
Net loss	(47,104,000)	0	0	0	(47,104,000)
Ending Balance at Mar. 31, 2021	67,846,000	$ 71,000	1,107,135,000	50,000	(1,039,410,000)
Ending Balance, shares at Mar. 31, 2021		71,563,040
Beginning Balance at Dec. 31, 2020	113,383,000	$ 70,000	1,105,470,000	149,000	(992,306,000)
Beginning Balance, shares at Dec. 31, 2020		71,015,183
Net loss	(108,658,000)
Ending Balance at Jun. 30, 2021	16,489,000	$ 72,000	1,117,403,000	(22,000)	(1,100,964,000)
Ending Balance, shares at Jun. 30, 2021		71,904,805
Beginning Balance at Mar. 31, 2021	67,846,000	$ 71,000	1,107,135,000	50,000	(1,039,410,000)
Beginning Balance, shares at Mar. 31, 2021		71,563,040
Exercise of stock options, value	2,207,000	$ 1,000	2,206,000	0	0
Exercise of stock options, shares		276,790
Stock-based compensation	7,093,000	$ 0	7,093,000	0	0
Issuance of common stock under Employee Stock Purchase Plan	969,000	$ 0	969,000	0	0
Issuance of common stock under Employee Stock Purchase Plan		64,975
Other comprehensive loss	(72,000)	$ 0	0	(72,000)	0
Net loss	(61,554,000)	0	0	0	(61,554,000)
Ending Balance at Jun. 30, 2021	$ 16,489,000	$ 72,000	$ 1,117,403,000	$ (22,000)	$ (1,100,964,000)
Ending Balance, shares at Jun. 30, 2021		71,904,805

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (108,658)	$ (80,185)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash interest expense on liability related to sale of future royalties	5,722	11,638
Non-cash stock-based compensation expense	12,354	8,051
Depreciation and amortization of property and equipment	1,080	824
Interest receivable and amortization on investments	2,016	27
Non-cash interest expense related to debt	3,425	3,301
Changes in operating assets and liabilities:
Accounts receivable	1,719	2,909
Prepaid and other assets	(5,581)	(160)
Operating lease right-of-use assets	3,126	2,058
Accounts payable	(2,380)	(5,240)
Accrued and other liabilities	3,034	1,454
Operating lease and other non-current liabilities	25,128	(2,251)
Net cash used in operating activities	(59,015)	(57,574)
Cash flows from investing activities:
Purchases of investments	(171,861)	(27,866)
Maturities of investments	197,584	107,897
Sales of investments	3,300	0
Purchases of property and equipment	(15,418)	(1,905)
Net cash provided by investing activities	13,605	78,126
Cash flows from financing activities:
Proceeds from and payments for stock-based award activities, net	(421)	1,998
Claims settlement under Section 16(b)	0	2,151
Net cash (used in) provided by financing activities	(421)	4,149
Net (decrease) increase in cash and cash equivalents	(45,831)	24,701
Cash and cash equivalents, beginning of period	82,985	36,433
Cash and cash equivalents, end of period	37,154	61,134
Non-cash investing and financing activities:
Right-of-use assets recognized in exchange for lease obligations	83,208	1,106
Amounts unpaid for purchases of property and equipment	$ 9,258	$ 0

Organization and Significant Accounting Policies

6 Months Ended

Jun. 30, 2021

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 $1,101.0 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, sale of future 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, 2020 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, 2020, 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 March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04’). ASU 2020-04 provides optional guidance for a limited period of time to ease the potential burden associated with the expected market transition from the London Inter-Bank Offer Rate ("LIBOR") to alternative reference rates. Companies can apply ASU 2020-04 immediately, however the guidance will only be available until December 31, 2022. The Company’s term loan utilizes LIBOR as the reference rate and we are currently evaluating the impact that adopting this new accounting standard will have on our Condensed Consolidated Financial Statements and related disclosures.

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”). ASU 2020-06 amends the guidance on convertible instruments and the derivatives scope exception for contracts in an entity's own equity, and also improves and amends the related earnings per share guidance. ASU 2020-06 will be effective for annual reporting periods after December 15, 2021 and interim periods within those annual periods and early adoption is permitted. We are currently evaluating the impact that adopting this new accounting standard will have on our Condensed Consolidated Financial Statements and related disclosures.

Net Loss Per Share

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Net Loss Per Share

Note 2 — Net Loss Per Share

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

	June 30, 2021		June 30, 2020
Options to purchase common stock		9,463		8,868
Warrants to purchase common stock		48		187
Restricted stock and performance units		1,562		1,130
Shares issuable related to the ESPP		10		8
Shares issuable upon conversion of convertible notes		16,675		16,675
Total shares		27,758		26,868

Research and Development Arrangements

6 Months Ended

Jun. 30, 2021

Research And Development [Abstract]

Research and Development Arrangements

Note 3 — Research and Development Arrangements

Amgen Inc. (“Amgen”)

On November 20, 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.

Omecamtiv mecarbil is an investigational cardiac myosin activator, developed for the potential treatment of heart failure with reduced ejection fraction (“HFrEF”), and was recently studied in GALACTIC-HF (Global Approach to Lowering Adverse Cardiac Outcomes Through Improving Contractility in Heart Failure), a positive Phase 3 cardiovascular outcomes clinical trial, and is the subject of an ongoing Phase 3 clinical trial, METEORIC-HF (Multicenter Exercise Tolerance Evaluation of Omecamtiv Mecarbil Related to Increased Contractility in Heart Failure), a Phase 3 clinical trial intended to evaluate the potential of omecamtiv mecarbil to increase exercise performance. CK-136, a novel mechanism cardiac troponin activator, was recently studied in a Phase 1 clinical study.

We recognize 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 as of May 20, 2021. Research and development revenue from Amgen of $2.5 million and $2.1 million for the three months ended June 30, 2021 and 2020, respectively, and $7.4 million and $4.4 million for the six months ended June 30, 2021 and 2020, respectively, consists of reimbursement of costs we incurred related to METEORIC-HF.

We had net accounts receivable of $2.5 million from Amgen as of June 30, 2021 and $1.7 million as of December 31, 2020.

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”).

In 2014, we and Astellas amended and restated the Astellas Agreement (the “2014 Astellas Amendment”) and expanded the objective of the collaboration to include spinal muscular atrophy (“SMA”) and potentially other neuromuscular indications for reldesemtiv and other fast skeletal muscle troponin activators (“FSTAs”). License revenues in 2018 related to our performance obligations under the 2014 Astellas Amendment. In 2018, we completed all our deliverables for the 2014 Astellas Amendment.

In 2016, we and Astellas amended the Astellas Agreement (the “2016 Astellas Amendment”) to expand the collaboration to include the development of reldesemtiv for the potential treatment of amyotrophic lateral sclerosis (“ALS”), as well as the possible development in ALS of other FSTAs previously licensed by us to Astellas, and Astellas paid us a $35.0 million non-refundable upfront amendment fee and an accelerated $15.0 million milestone payment for the initiation of the first Phase 2 clinical trial of reldesemtiv in ALS that was otherwise provided for in the Astellas Agreement, as if such milestone had been achieved upon the execution of the 2016 Astellas Amendment, and committed research and development consideration of $44.2 million, for total consideration of $94.2 million.

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 that certain 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 has agreed to pay one-third of the out-of-pocket clinical development costs which may be incurred in connection with the Company’s potential Phase 3 clinical trial of reldesemtiv in ALS, up to a maximum contribution by Astellas of $12 million. In addition, Astellas has 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 would 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, which is effective as of 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 $0.3 million and $1.2 million for the three months ended June 30, 2021 and 2020 respectively, and $2.0 million and $2.7 million for the six months ended June 30, 2021 and 2020, respectively.

We had accounts receivable from Astellas of $0.2 million as of June 30, 2021 and $2.7 million as of December 31, 2020.

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 Pharmaceuticals Limited (“Ji Xing”), related to aficamten, our proprietary small molecule cardiac myosin inhibitor product also referred to as CK-3773274 or CK-274, a novel cardiac myosin inhibitor, and other assets (together, the “RTW Transactions”). The RTW Transactions include entering into a licensing and collaboration agreement with Ji Xing, the sale of Cytokinetics common stock to the RTW Investors (as defined below), 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 or expect to receive a combination of committed capital, funding and sale proceeds from the RTW Investors, RTW Royalty Holdings and Ji Xing.

The RTW Transactions were entered into with parties that are 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 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 Consideration
Units of Accounting:
License and collaboration (residual)	$	36,501
Royalty (fair value)		87,000
Common stock (fair value)		36,499
Total consideration	$	160,000

License and Collaboration Agreement

We entered into a License and Collaboration Agreement (the “Ji Xing License Agreement”) with Ji Xing, pursuant to which we granted to Ji Xing an exclusive license to develop and commercialize aficamten in People’s Republic of China (including the Hong Kong SAR and Macau SAR) (together “China”) and Taiwan. Under the terms of the Ji Xing 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 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 License Agreement for convenience. Each party may terminate the Ji Xing 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 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.

License revenues and milestone revenues for 2020 were $36.5 million and $2.5 million, respectively. No license revenues or milestone revenues were recognized for the three and six months ended June 30, 2021.

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 for the three and six months ended June 30, 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 exclude the milestone payments from the initial transaction price.

The consideration related to sales-based milestone payments, including royalties, will be recognized when the related sales occur under the sales- and usage-based royalty exception 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 earned a $2.5 million milestone from Ji Xing as of December 31, 2020 for the first patient dosed in Cohort 2 of REDWOOD-HCM (Randomized Evaluation of Dosing With CK-274 in Obstructive Outflow Disease in HCM). We determined recognition of the milestone during 2020 based on clinical trial progress. Our determination that we expected to earn the $2.5 million milestone resulted in a change in the overall transaction price of the collaboration agreement, as it was probable that a significant reversal of cumulative revenue would not occur. A corresponding contract asset was recorded in other current assets in our condensed consolidated balance sheet as of December 31, 2020 and was released in the first quarter of 2021 upon receipt of cash.

Royalty Purchase Agreement

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”).

We accounted for the sale of our rights to the Mavacamten Royalty as deferred revenue under ASC 470, Debt, since the arrangement is a sale of our future right to receive royalties and not a sale of the underlying patents or related intangibles. Further, we do not have any significant continuing involvement in the further development, commercialization or sale of mavacamten, the one-time payment is not required to be paid back to RTW Royalty Holdings, the investor’s return is not limited and will be driven by net sales, and RTW Royalty Holdings does not have any recourse to the Company’s assets.

The allocation of the consideration for the RTW Transactions resulted in $87.0 million being allocated to the RTW Royalty Purchase Agreement representing its fair value. The fair value was determined using an income approach method based on management’s estimates of the discounted cash flows to be received over the term of the related royalty agreement, which are Level 3 fair value inputs. Management’s estimates included significant unobservable inputs. These inputs are derived using internal management estimates developed based on third party data and reflect management’s 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. 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 Agreement

On July 14, 2020, we entered into Common Stock Purchase Agreements (each, a “CSPA”) with each of RTW Master Fund, Ltd., RTW Innovation Master Fund, Ltd. and RTW Venture Fund Limited (collectively, the “RTW Investors”). The CSPAs provided for the sale and issuance of an aggregate of 2.0 million shares of common stock of Cytokinetics (the “Shares”) 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, 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. 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

We entered into a Funding Agreement (the “Funding Agreement”) with RTW Royalty Holdings. Pursuant to the Funding Agreement, RTW Royalty Holdings has committed to provide up to $90.0 million (the “Funding Commitment”) to fund our development and commercialization of aficamten in nHCM and oHCM. Half of the Funding Commitment will be available, at our option, if certain clinical trial milestones of aficamten for oHCM are achieved by January 14, 2023, and the remaining $45.0 million of the Funding Commitment will be available, at our option, if certain clinical trial milestones of aficamten for nHCM are achieved by January 14, 2024. If we develop aficamten in another indication, we will negotiate an additional funding commitment from RTW to fund our development and commercialization of aficamten in such other indication (other than oHCM or nHCM).

In exchange for the Funding Commitment and upon receipt of such funding from RTW Royalty Holdings, we have agreed to make payments to RTW Royalty Holdings equal to 2%, if RTW Royalty Holdings funds $45.0 million of the Funding Commitment, or 4%, if RTW Royalty Holdings funds the full $90.0 million of the Funding Commitment, in each case in respect of net sales of aficamten by us and any of our licensees in the United States, the European Union, Switzerland, the United Kingdom and certain other countries in Europe (collectively referred to as the “Aficamten Territory”). In addition, should we exercise our option draw borrowings pursuant to the Funding Agreement, such agreement contains certain covenants applicable to us, including, among other things, development and commercialization diligence obligations in connection to the Aficamten Territory, use of proceeds, reporting and encumbrances. There are no performance obligations related to the Funding Agreement, as access to the Funding Commitment is at the option of the Company and based upon the achievement of certain development milestones.

The Funding Agreement contains customary conditions to disbursement, which may include the consent of our Lenders at the time of disbursement. On July 16, 2020, we entered into an amendment to the Term Loan Agreement, which permits, subject to entry into an intercreditor agreement between Oxford (as security agent for the Lenders) and RTW Royalty Holdings in form and substance reasonably satisfactory to the Lenders and RTW Royalty Holdings, the draw of funding under the Funding Agreement and the grant of a security interest to RTW Royalty Holdings in the intellectual property located in the United States and accounts receivable related to aficamten thereunder.

The Company granted RTW Royalty Holdings a security interest in all of its rights, title and interest in, to certain intellectual property, accounts receivable and any proceeds from such collateral. The security interest will automatically terminate when total net payments made to RTW Royalty Holdings exceed a certain agreed threshold.

On March 31, 2021, RTW Royalty Holdings assigned its rights and obligations under the Funding Agreement to its affiliate, RTW ICAV.

Fair Value Measurements

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 4 — Fair Value Measurements

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

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

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

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

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

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

Fair value of financial assets:

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

		June 30, 2021
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	35,401	$	—	$	—		$	35,401
U.S. Treasury securities	Level 1		174,077		31		(6	)		174,102
Agency bonds	Level 2		43,907		11		(3	)		43,915
Commercial paper	Level 2		51,444		10		(1	)		51,453
Corporate obligations	Level 2		117,413		8		(72	)		117,349
		$	422,242	$	60	$	(82	)	$	422,220

		December 31, 2020
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	80,050	$	—	$	—		$	80,050
U.S. Treasury securities	Level 1		274,407		147		(8	)		274,546
Agency bonds	Level 2		51,581		15		(3	)		51,593
Commercial paper	Level 2		49,500		3		(1	)		49,502
Corporate obligations	Level 2		42,392		7		(11	)		42,388
		$	497,930	$	172	$	(23	)	$	498,079

The available-for-sale securities in our condensed consolidated balance sheet are as follows (in thousands):

	June 30, 2021		December 31, 2020
Cash equivalents	$	35,401	$	80,050
Short-term investments		313,147		381,075
Long-term investments		73,672		36,954
	$	422,220	$	498,079

Interest income, net was $0.2 million and $1.4 million for three months ended June 30, 2021 and 2020, respectively, and $0.5 million and $2.1 million for the six months ended June 30, 2021 and 2020, respectively.

No credit losses on debt securities were recorded during the six months ended June 30, 2021 or 2020. 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 approximates fair value due to the short-term nature of these instruments.

Fair value of financial liabilities:

As of June 30, 2021, the fair value of our term loan approximated its carrying value of $46.8 million based upon a market observable interest rate, which is a Level 2 input (see Note 6 – “Debt”).

As of June 30, 2021, the estimated fair value of our convertible notes was $310.7 million and was based upon observable, Level 2 inputs, including pricing information from recent trades of the convertible notes (see Note 6 – “Debt”).

As of June 30, 2021, the fair value of the liability related to the sale of future royalties to RPI Finance Trust (“RPI”) is consistent with its carrying value of $171.8 million, and is based on our current estimates of future royalties expected to be paid to RPI under the Royalty Purchase Agreement dated February 1, 2017 between us and RPI (the “RPI Royalty Purchase Agreement”), over the life of the arrangement, which are considered Level 3 inputs (See Note 7 – “Liability Related to Sale of Future Royalties”).

There were no transfers between Level 1, Level 2, and Level 3 during the periods presented.

- Definition

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

+ References + Details

Balance Sheet Components

6 Months Ended

Jun. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Balance Sheet Components

Note 5 — Balance Sheet Components

Accrued liabilities were as follows (in thousands):

	June 30, 2021		December 31, 2020
Accrued liabilities:
Clinical and preclinical costs	$	10,921	$	6,124
Compensation related		8,779		11,787
Other accrued expenses		2,694		1,404
Total accrued liabilities	$	22,394	$	19,315

Debt

6 Months Ended

Jun. 30, 2021

Debt Disclosure [Abstract]

Debt

Note 6 — Debt

Term Loan

Prior to May 17, 2019 we maintained a loan and security agreement dated as of October 19, 2015, as amended (the “Original Loan Agreement”) with Oxford Finance LLC (“Oxford”) and Silicon Valley Bank (“SVB”) (Oxford and SVB, collectively the “Lenders”) to fund our working capital and other general corporate needs.

On May 17, 2019, we entered into a new loan and security agreement (the “Term Loan Agreement”) with the Lenders for $45.0 million (the “Term Loan”) and terminated the Original Loan Agreement. The proceeds of the Term Loan were used in part to repay in full all of the outstanding term loans under the Original Loan Agreement in an aggregate principal amount of $42.0 million. On November 6, 2019 and November 7, 2019, the Company entered into a First Amendment and a Second Amendment to the Term Loan Agreement. The Term Loan Agreement, as amended, permits the issuance of the Convertible Notes and Capped Call Transactions discussed below. On July 16, 2020, the Company and the Lenders entered into the Third Amendment to the Term Loan Agreement, which amended the Term Loan Agreement to permit (i) the sale of the Mavacamten Royalty under the RTW Royalty Purchase Agreement and (ii) subject to entry into an intercreditor agreement between Oxford (as security agent for the Lenders) and RTW Royalty Holdings in form and substance reasonably satisfactory to the Lenders and RTW Royalty Holdings, permits the draw of funding under the Funding Agreement and the grant of a security interest to RTW Royalty Holdings in the intellectual property located in the United States and accounts receivable related to aficamten.

The Term Loan was accounted for as a debt modification in a non-troubled debt restructuring based on a comparison of the present value of the cash flows under the terms of the debt immediately before and after the effective date of the Term Loan, which resulted in a change of less than 10%. As a result, issuance costs paid to the Lenders in connection with the Term Loan were recorded as a reduction of the carrying amount of the debt liability and were not significant. Unamortized issuance costs as of the date of the modification were amortized to interest expense over the repayment term of Term Loan.

Both borrowings under the Original Loan Agreement and Term Loan bear 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 Original Loan Agreement was repayable in monthly interest-only payments through November 2019 followed by 35 months of monthly payments of interest and principal. The borrowing under the Term Loan is 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 cardiomyopathy and has been 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 will be followed by equal monthly payments of principal and interest to the maturity date in December 2023. We are required to make a final payment upon loan maturity of 6.00% of the notes payable, which we accrete over the life of the Term Loan. Our obligations under the Term Loan Agreement are secured by substantially all our current and future assets, other than our intellectual property.

Interest expense for the Term Loan was $1.2 million for the three months ended June 30, 2021 and 2020, and $2.4 million and $2.5 million for the six months ended June 30, 2021 and 2020, respectively. As of June 30, 2021, the interest rate applicable to borrowings under the Term Loan was 8.05%.

The Term Loan Agreement contains customary representations and warranties and customary affirmative and negative covenants applicable to us and includes customary events of default, including but not limited to the nonpayment of principal or interest, violations of covenants and material adverse changes. Upon an event of default, the Lenders may, among other things, accelerate the loans and foreclose on the collateral. Our obligations under the Term Loan Agreement are secured by substantially all our current and future assets, other than our intellectual property. If the Term Loan becomes subject to mandatory prepayment under these provisions, we are subject to certain prepayment premiums of 3.00% in the first year, 2.00% in the second year and 1.00% in the third year and thereafter. We determined that these contingent prepayment provisions were an embedded component that qualified as a derivative which should be bifurcated from the Term Loan and accounted for separately from the host contract. As of June 30, 2021, the fair value of this embedded derivative was immaterial.

Future minimum payments under the Term Loan Agreement are (in thousands):

Years ending December 31:
2021 remainder	$	1,841
2022		25,330
2023		28,080
Future minimum payments		55,251
Less: Interest and final payment		(10,251	)
Term Loan, gross	$	45,000

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.

In accounting for the issuance of the 2026 Notes, the Company separated the 2026 Notes into liability and equity components. The carrying amount of the liability component of approximately $84.2 million was calculated by using a discount rate of 12.0%, which was estimated to be the Company’s borrowing rate on the date of the issuance of the notes for a similar debt instrument without the conversion feature. The carrying amount of the equity component of approximately $49.5 million, representing the conversion option, was determined by deducting the fair value of the liability component from the par value of the 2026 Notes. The equity component of the 2026 Notes is included in additional paid-in capital in the consolidated balance sheets and is not remeasured as long as it continues to meet the conditions for equity classification. The difference between the principal amount of the 2026 Notes and the liability component (the “debt discount”) is amortized to interest expense using the effective interest method over the term of the 2026 Notes.

Debt issuance costs for the issuance of the 2026 Notes were approximately $5.0 million, consisting of initial purchasers' discount and other issuance costs. In accounting for the transaction costs, the Company allocated the total amount incurred to the liability and equity components using the same proportions as the proceeds from the 2026 Notes. Transaction costs attributable to the liability component were approximately $3.1 million, were recorded as debt issuance cost (presented as contra debt in the consolidated balance sheet) and are being amortized to interest expense over the term of the 2026 Notes. The transaction costs attributable to the equity component were approximately $1.9 million and were netted with the equity component in stockholders’ equity. As of June 30, 2021, the unamortized debt issuance cost for the 2026 Notes was $2.6 million.

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

	Three Months Ended June 30, 2021		Six Months Ended June 30, 2021
Contractual interest expense	$	1,380	$	2,760
Amortization of debt discount		1,445		2,816
Amortization of debt issuance costs		14		28
Total interest costs recognized	$	2,839	$	5,604

The effective interest rate on the liability component of the 2026 Notes was 12.5% for the period ended June 30, 2021, which remains unchanged from the date of issuance. The remaining unamortized debt discount was $43.0 million as of June 30, 2021 and will be amortized over approximately 5.5 years. If the 2026 Notes were to be converted on June 30, 2021, the holders of the 2026 Notes would receive common shares of 16,675 with an aggregate value of $330.0 million based on the Company’s closing stock price of $19.79 as of June 30, 2021. The if-converted value of the 2026 Notes exceeded its principal amount by $192.0 million as of June 30, 2021.

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

Years ending December 31:
2021 remainder	$	2,760
2022		5,520
2023		5,520
2024		5,520
2025		5,520
Thereafter		143,520
Future minimum payments		168,360
Less: Interest		(30,360	)
The 2026 Notes, principal amount		138,000
Less: Debt discount and debt issuance costs on the 2026 Notes		(45,652	)
Net carrying amount of the 2026 Notes	$	92,348

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 June 30, 2021, the Company had not purchased any shares under the convertible note capped call transactions.

Liability Related to Sale of Future Royalties

6 Months Ended

Jun. 30, 2021

Royalty Liability [Abstract]

Note 7 — Liability Related to Sale of Future Royalties

In February 2017, we entered into the RPI Royalty Purchase Agreement under which we sold a portion of our right to receive royalties on potential net sales of omecamtiv mecarbil (and potentially other compounds with the same mechanism of action) under the Amgen Agreement to RPI for a payment of $90.0 million, which is non-refundable even if omecamtiv mecarbil is never commercialized. Concurrently, we entered into a common stock purchase agreement with RPI through which RPI 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 the liability related to the sale of future royalties (the “RPI Liability”) and the common stock, which resulted in the RPI Liability being initially recognized at $92.3 million.

The RPI Royalty Purchase Agreement further provides that in the event Amgen elects to terminate the Amgen Agreement, we are obliged to enter into an agreement with RPI to preserve RPI’s rights under the RPI Royalty Purchase Agreement, which includes the payment by Cytokinetics of 4.5% of its worldwide net sales of omecamtiv mecarbil and other Amgen Alliance Compounds, subject to a potential increase of up to an additional 1% under certain circumstances (delay in US marketing approval). Our obligation to enter into a new agreement with RPI does not impact our accounting treatment of the RPI Liability or our estimates.

We account for the RPI Liability as a liability primarily because we have significant continuing involvement in generating the royalty stream. If and when omecamtiv mecarbil is commercialized and royalties become payable, we will recognize the portion of royalties paid to RPI as a decrease to the RPI Liability with a corresponding reduction in cash.

The carrying amount of the RPI Liability is based on our estimate of the future royalties to be paid to RPI 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 RPI Liability was approximately 7% as of June 30, 2021 and 15% as of December 31, 2020.

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 RPI 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 RPI Liability is recognized using significant unobservable inputs. These inputs are derived using internal management estimates developed based on third party data, including data historically provided by Amgen, 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 RPI Liability.

During the three months ended June 30, 2021, there were no changes to the significant unobservable inputs, however for the six months ended June 30, 2021 we updated our analyses to reflect current assumptions resulting from ongoing market research in the U.S. and to reflect other adjustments in connection with our anticipated commercialization plans in other key markets outside of the U.S. 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 was 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 $5.7 million for the three months ended December 31, 2020 to 7% and $2.8 million for the three months ended March 31, 2021, respectively. During the three months ended June 30, 2021, there were no changes to the significant unobservable inputs used to recognize the RPI Liability. During the six months ended June 30, 2021, the change in estimate had no impact on revenue and reduced the net loss by $2.8 million. The change in accounting estimate reduced the net loss per share by $0.04 during the six months ended June 30, 2021. Our estimates may change in the future as we refine and reassess our assumptions.

Changes to the RPI Liability related to the sale of future royalties are as follows (in thousands):

	2021		2020
Beginning balance, January 1	$	166,068	$	143,276
Interest accretion		2,795		5,689
Amortization of issuance costs		27		18
Ending balance, March 31		168,890		148,983
Interest accretion		2,871		5,912
Amortization of issuance costs		29		19
Ending balance, June 30	$	171,790	$	154,914

We recognized $2.9 million and $5.9 million in non-cash interest expense for the three months ended June 30, 2021 and 2020, respectively, and $5.7 million and $11.6 million for the six months ended June 30, 2021 and 2020, respectively, related to the RPI Agreement.

Stockholders' Equity

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Stockholders' Equity

Note 8 — Stockholders’ Equity

Warrants

During the first quarter of 2020, in connection with the Term Loan Agreement further described in Note 6 - Debt, we issued a warrant with an exercise price of $10.42 per share to purchase 21,595 shares of our common stock. The warrant was issued in connection with achieving the interest-only extension milestone 1 in the Term Loan Agreement. The warrant was fully exercisable and expires in January 2030. The $0.2 million fair value of the warrant related to the Term Loan was recorded as interest expense during the first quarter of 2020.

Claims settlement

In the first quarter of 2020, we received $2.2 million from a claims settlement with certain institutional investors that were beneficial owners of our common stock related to the disgorgement of short swing profits pursuant to Section 16(b) of the Securities Exchange Act of 1934, as amended. This settlement was recognized in equity as additional paid-in capital.

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 new drug application (“NDA”) for omecamtiv mecarbil has been filed and accepted by the U.S. Food and Drug Administration (“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. During the three-months ended June 30, 2021, the Company recognized expense of $0.7 million for the first tranche of PSUs. No expense has been recognized for the second tranche. The Company will assess the likelihood of achieving the performance conditions quarterly and the expense recognized will be adjusted accordingly.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 9 — Commitments and Contingencies

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. As of June 30, 2021, the remaining lease term is 1.0 years, and the discount rate used to determine the operating lease liability was 6.8%.

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 and January 2021, we entered into first and second 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 expires on 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. We will be required to start making rent payments in October 2021. As of June 30, 2021, the remaining lease term of the Oyster Point Lease is 12.3 years and the discount rate used to determine the related lease liability was 9.8%. We paid a total security deposit of $5.1 million in December 2019 and December 2020. The landlord will provide a tenant improvement allowance of $43.6 million in aggregate for costs relating to the initial design and construction of the improvements. As of June 30, 2021, we had $32.4 million in construction in progress related to the Oyster Point Lease and the total commitment of undiscounted lease payments for the Oyster Point Lease was $230.5 million.

The undiscounted future non-cancellable lease payments under all our lease agreements as of June 30, 2021 is as follows (in thousands):

Years ending December 31:
2021 remainder	$	4,133
2022		16,098
2023		17,216
2024		17,668
2025		18,249
Thereafter		163,434
Total undiscounted future lease payments		236,798
Less: Present value adjustments		(128,895	)
Total lease liability	$	107,903

As of June 30, 2021, the weighted average remaining lease term is 12.0 years and the weighted average discount rate used to determine the operating lease liability is 9.8%.

Cash paid for amounts included in the measurement of lease liabilities for the six months ended June 30, 2021 and 2020 was $2.6 million and $3.6 million, respectively, and was included in net cash used in operating activities in our condensed consolidated statements of cash flows.

Rent expense was $5.3 million and $1.4 million for the three months ended June 30, 2021 and 2020, respectively, and $6.7 million and $2.8 million for the six months ended June 30, 2021 and 2020, respectively.

Subsequent Events

6 Months Ended

Jun. 30, 2021

Subsequent Events [Abstract]

Subsequent Events

Note 10 – Subsequent Events

Public Offering of Common Stock

On July 23, 2021, we closed an underwritten public offering of 11,500,000 shares of our common stock at a public offering price of $27.50, which included the exercise in full by the underwriters of their option to purchase up to 1,500,000 shares of our common stock at the same price. The gross proceeds were $316.3 million and net proceeds were approximately $297.3 million, after deducting the applicable underwriting discounts and commissions.

Organization and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
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 $1,101.0 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, sale of future 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, 2020 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, 2020, 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 March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04’). ASU 2020-04 provides optional guidance for a limited period of time to ease the potential burden associated with the expected market transition from the London Inter-Bank Offer Rate ("LIBOR") to alternative reference rates. Companies can apply ASU 2020-04 immediately, however the guidance will only be available until December 31, 2022. The Company’s term loan utilizes LIBOR as the reference rate and we are currently evaluating the impact that adopting this new accounting standard will have on our Condensed Consolidated Financial Statements and related disclosures. 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”). ASU 2020-06 amends the guidance on convertible instruments and the derivatives scope exception for contracts in an entity's own equity, and also improves and amends the related earnings per share guidance. ASU 2020-06 will be effective for annual reporting periods after December 15, 2021 and interim periods within those annual periods and early adoption is permitted. We are currently evaluating the impact that adopting this new accounting standard will have on our Condensed Consolidated Financial Statements and related disclosures.

Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Instruments Excluded from the Computation of Diluted Net Loss Per Share

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

	June 30, 2021		June 30, 2020
Options to purchase common stock		9,463		8,868
Warrants to purchase common stock		48		187
Restricted stock and performance units		1,562		1,130
Shares issuable related to the ESPP		10		8
Shares issuable upon conversion of convertible notes		16,675		16,675
Total shares		27,758		26,868

Research and Development Arrangements (Tables)

6 Months Ended

Jun. 30, 2021

Research And Development [Abstract]

Schedule of Allocated Consideration

	Allocated Consideration
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)

6 Months Ended

Jun. 30, 2021

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

		June 30, 2021
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	35,401	$	—	$	—		$	35,401
U.S. Treasury securities	Level 1		174,077		31		(6	)		174,102
Agency bonds	Level 2		43,907		11		(3	)		43,915
Commercial paper	Level 2		51,444		10		(1	)		51,453
Corporate obligations	Level 2		117,413		8		(72	)		117,349
		$	422,242	$	60	$	(82	)	$	422,220

		December 31, 2020
	Fair Value Hierarchy Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	Level 1	$	80,050	$	—	$	—		$	80,050
U.S. Treasury securities	Level 1		274,407		147		(8	)		274,546
Agency bonds	Level 2		51,581		15		(3	)		51,593
Commercial paper	Level 2		49,500		3		(1	)		49,502
Corporate obligations	Level 2		42,392		7		(11	)		42,388
		$	497,930	$	172	$	(23	)	$	498,079

The available-for-sale securities in our condensed consolidated balance sheet are as follows (in thousands):

	June 30, 2021		December 31, 2020
Cash equivalents	$	35,401	$	80,050
Short-term investments		313,147		381,075
Long-term investments		73,672		36,954
	$	422,220	$	498,079

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Accrued Liabilities

Accrued liabilities were as follows (in thousands):

	June 30, 2021		December 31, 2020
Accrued liabilities:
Clinical and preclinical costs	$	10,921	$	6,124
Compensation related		8,779		11,787
Other accrued expenses		2,694		1,404
Total accrued liabilities	$	22,394	$	19,315

Debt (Tables)

6 Months Ended

Jun. 30, 2021

Debt Disclosure [Abstract]

Schedule of Future Minimum Payments under Term Loan Agreement

Future minimum payments under the Term Loan Agreement are (in thousands):

Years ending December 31:
2021 remainder	$	1,841
2022		25,330
2023		28,080
Future minimum payments		55,251
Less: Interest and final payment		(10,251	)
Term Loan, gross	$	45,000

Schedule of Interest Cost Relating to 2026 Notes

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

	Three Months Ended June 30, 2021		Six Months Ended June 30, 2021
Contractual interest expense	$	1,380	$	2,760
Amortization of debt discount		1,445		2,816
Amortization of debt issuance costs		14		28
Total interest costs recognized	$	2,839	$	5,604

Schedule of Maturities of 2026 Notes

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

Years ending December 31:
2021 remainder	$	2,760
2022		5,520
2023		5,520
2024		5,520
2025		5,520
Thereafter		143,520
Future minimum payments		168,360
Less: Interest		(30,360	)
The 2026 Notes, principal amount		138,000
Less: Debt discount and debt issuance costs on the 2026 Notes		(45,652	)
Net carrying amount of the 2026 Notes	$	92,348

Liability Related to Sale of Future Royalties (Tables)

6 Months Ended

Jun. 30, 2021

Royalty Liability [Abstract]

Schedule of Activity within Liabilities Related to Sale of Future Royalties

Changes to the RPI Liability related to the sale of future royalties are as follows (in thousands):

	2021		2020
Beginning balance, January 1	$	166,068	$	143,276
Interest accretion		2,795		5,689
Amortization of issuance costs		27		18
Ending balance, March 31		168,890		148,983
Interest accretion		2,871		5,912
Amortization of issuance costs		29		19
Ending balance, June 30	$	171,790	$	154,914

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2021

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 June 30, 2021 is as follows (in thousands):

Years ending December 31:
2021 remainder	$	4,133
2022		16,098
2023		17,216
2024		17,668
2025		18,249
Thereafter		163,434
Total undiscounted future lease payments		236,798
Less: Present value adjustments		(128,895	)
Total lease liability	$	107,903

Organization and Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Accumulated deficit incurred	$ (1,100,964)	$ (992,306)
Cash requirements term	12 months

Net Loss Per Share - Instruments Excluded from the Computation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	27,758	26,868
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	9,463	8,868
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	48	187
Restricted Stock and Performance Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	1,562	1,130
Shares Issuable Related to the ESSP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares	10	8
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 Arrangements - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions			3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 14, 2020	Apr. 23, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2016	Jan. 14, 2024
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 2,843,000	$ 3,593,000	$ 9,391,000	$ 7,418,000
Accounts receivable			2,701,000		2,701,000		$ 4,420,000
Amount received as milestone payment							2,500,000
Long-term deferred revenue			87,000,000		87,000,000		87,000,000
License And Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront Payment Received	$ 25,000,000.0
Royalty Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sale of interest in future royalties							85,000,000.0
Fair Value of Royalty	$ 87,000,000.0
Long-term deferred revenue			87,000,000.0		87,000,000.0
Common Stock Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock upon private placement, shares	2.0
Shares Issued, price per share	$ 25.00
Net proceeds of issuance of common stock	$ 50,000,000.0
Common stock purchase agreement date	Jul. 14, 2020
Excess amount paid over the fair value of the shares	$ 13,500,000
Fair value of common stock	36,500,000
Funding Agreement [Member] \| Forecast
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone receivable									$ 45,000,000.0
Maximum [Member] \| License And Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone receivable	200,000,000.0
Maximum [Member] \| Funding Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone receivable	$ 90,000,000.0
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
Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			2,843,000	3,593,000	9,391,000	7,418,000
License [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			0		0		36,500,000
Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues					0		2,500,000
Amgen \| Research And Development Milestone Grant And Other Revenues Net
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			2,500,000	2,100,000	7,400,000	4,400,000
Accounts receivable			2,500,000		2,500,000		1,700,000
Astellas [Member] \| Accounting Standards Update 2014-09
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable			200,000		200,000		$ 2,700,000
Astellas [Member] \| 2016 Astellas Amendment [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognition, Non-refundable upfront amendment fee								$ 35,000,000.0
Amount received as milestone payment								15,000,000.0
Revenue recognition over performance period								44,200,000
Allocated consideration								$ 94,200,000
Astellas [Member] \| Research and Development Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 300,000	$ 1,200,000	$ 2,000,000.0	$ 2,700,000

Research and Development Arrangements - Schedule of Allocated Consideration (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jul. 14, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
License and collaboration (residual)		$ 2,843	$ 3,593	$ 9,391	$ 7,418
Collaborative Arrangement [Member] \| RTW [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Total consideration	$ 160,000
Collaborative Arrangement [Member] \| RTW [Member] \| Common Stock [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Common stock (fair value)	36,499
Collaborative Arrangement [Member] \| RTW [Member] \| License and Collaboration [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
License and collaboration (residual)	36,501
Collaborative Arrangement [Member] \| RTW [Member] \| Royalty [Member]
Allocated Transaction Prices Of Collaborative Arrangements [Line Items]
Royalty (fair value)	$ 87,000

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	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	$ 422,220	$ 498,079
Long-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	73,672	36,954
Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	35,401	80,050
Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	313,147	381,075
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	422,242	497,930
Unrealized Gains	60	172
Unrealized Losses	(82)	(23)
Fair Value	422,220	498,079
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	35,401	80,050
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	35,401	80,050
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	174,077	274,407
Unrealized Gains	31	147
Unrealized Losses	(6)	(8)
Fair Value	174,102	274,546
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	43,907	51,581
Unrealized Gains	11	15
Unrealized Losses	(3)	(3)
Fair Value	43,915	51,593
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	51,444	49,500
Unrealized Gains	10	3
Unrealized Losses	(1)	(1)
Fair Value	51,453	49,502
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	117,413	42,392
Unrealized Gains	8	7
Unrealized Losses	(72)	(11)
Fair Value	$ 117,349	$ 42,388

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Interest Income	$ 200,000	$ 1,400,000	$ 500,000	$ 2,100,000
Credit losses on debt securities			0	0
Long-term debt, fair value	46,800,000		46,800,000
Convertible debt, fair value	310,700,000		310,700,000
Liability related to the sale of future royalties, net	171,790,000	$ 154,914,000	171,790,000	$ 154,914,000	$ 168,890,000	$ 166,068,000	$ 148,983,000	$ 143,276,000
Fair value of liabilities transferred from level 1 to level 2	0		0
Fair value of liabilities transferred from level 2 to level 1	$ 0		0
Fair value of liabilities transferred into level 3			0
Fair value of liabilities transferred from level 3			$ 0

Balance Sheet Components - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued liabilities:
Clinical and preclinical costs	$ 10,921	$ 6,124
Compensation related	8,779	11,787
Other accrued expenses	2,694	1,404
Total accrued liabilities	$ 22,394	$ 19,315

Debt - Additional Information (Detail)			3 Months Ended		6 Months Ended
Debt - Additional Information (Detail)	Nov. 13, 2019 USD ($) $ / shares shares	Nov. 07, 2019 $ / shares	Jun. 30, 2021 USD ($) $ / shares	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Installment Day $ / shares shares	Jun. 30, 2020 USD ($)	May 17, 2019 USD ($)
Debt Instrument [Line Items]
Interest expense			$ 4,073,000	$ 3,892,000	$ 8,061,000	$ 7,969,000
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]
Principal amount of original loan							$ 45,000,000.0
Oxford and Silicon Valley Bank [Member] \| 2019 Term Loan [Member] \| Term Loan Agreement [Member]
Debt Instrument [Line Items]
Principal amount of original loan							$ 42,000,000.0
Interest expense			$ 1,200,000	$ 1,200,000	$ 2,400,000	$ 2,500,000
Stated interest rate on the amounts borrowed under the Agreement			8.05%		8.05%
Prepayment fee percentage in fiscal year					3.00%
Prepayment fee percentage in year two					2.00%
Prepayment fee percentage in year three					1.00%
Oxford and Silicon Valley Bank [Member] \| 2019 Term Loan [Member] \| Amended Loan Agreement [Member]
Debt Instrument [Line Items]
Loan repayment terms					The borrowing under the Original Loan Agreement was repayable in monthly interest-only payments through November 2019 followed by 35 months of monthly payments of interest and principal
Number of instalments description					35 months of monthly payments of interest and principal
Number of instalments \| Installment					35
Debt instrument, applicable interest rate for scenario 1			8.05%		8.05%
Debt instrument, base interest rate for scenario 2			6.81%		6.81%
Interest rate description					Both borrowings under the Original Loan Agreement and Term Loan bear 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.
Debt instrument, maturity year and month					Dec. 31, 2023
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 is 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 cardiomyopathy and has been 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 will be followed by equal monthly payments of principal and interest to the maturity date in December 2023
Final payment fee percentage					6.00%
Convertible Notes 2026 [Member]
Debt Instrument [Line Items]
Principal amount of original loan	$ 138,000,000.0		$ 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
Debt instrument, maturity year and month	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
Carrying amount of the liability component	84,200,000
Carrying amount of the equity component	$ 49,500,000
Debt instrument interest, discount rate	12.00%
Debt issuance costs	$ 5,000,000.0
Unamortized debt issuance cost			2,600,000		$ 2,600,000
Debt instrument, unamortized discount			$ 43,000,000.0		$ 43,000,000.0
Unamortized debt discount amortization period					5 years 6 months
If-converted value in excess of principal amount					$ 192,000,000.0
Conversion of units, share \| shares					16,675
Conversion of units					$ 330,000,000.0
Stock price \| $ / shares			$ 19.79		$ 19.79
Convertible Notes 2026 [Member] \| Equity [Member]
Debt Instrument [Line Items]
Debt issuance costs	1,900,000
Convertible Notes 2026 [Member] \| Liability [Member]
Debt Instrument [Line Items]
Debt issuance costs	$ 3,100,000
Debt instrument effective interest rate			12.50%		12.50%
Convertible Notes 2026 [Member] \| Debt Instrument Convertible Covenant One [Member]
Debt Instrument [Line Items]
Convertible notes, percentage of conversion price					127.50%
Convertible notes, trading days \| Day					20
Convertible notes, consecutive trading days \| Day					30
Convertible Notes 2026 [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 \| Day					5
Convertible notes, consecutive trading days \| Day					10

Debt - Schedule of Future Minimum Payments under Term Loan Agreement (Detail) - Term Loan Agreement [Member] - Oxford and Silicon Valley Bank [Member] $ in Thousands	Jun. 30, 2021 USD ($)
Debt Instrument [Line Items]
2021 remainder	$ 1,841
2022	25,330
2023	28,080
Future minimum payments	55,251
Long-term debt, alternative
Future minimum payments	55,251
Less: Interest and final payment	(10,251)
Term Loan, gross	$ 45,000

Debt - Schedule of Interest Cost Relating to 2026 Notes (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021
Debt Instrument [Line Items]
Amortization of debt issuance costs	$ 29	$ 27	$ 19	$ 18
Convertible Notes 2026 [Member]
Debt Instrument [Line Items]
Contractual interest expense	1,380				$ 2,760
Amortization of debt discount	1,445				2,816
Amortization of debt issuance costs	14				28
Total interest costs recognized	$ 2,839				$ 5,604

Debt - Schedule of Future Minimum Payments under 2026 Notes (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Nov. 13, 2019
Debt Instrument [Line Items]
Net carrying amount of the 2026 Notes	$ 92,348	$ 89,504
Convertible Notes 2026 [Member]
Debt Instrument [Line Items]
2021 remainder	2,760
2022	5,520
2023	5,520
2024	5,520
2025	5,520
Thereafter	143,520
Future minimum payments	168,360
Less: Interest	(30,360)
The 2026 Notes, principal amount	138,000		$ 138,000
Less: Debt discount and debt issuance costs on the 2026 Notes	(45,652)
Net carrying amount of the 2026 Notes	$ 92,348

Liability Related to Sale of Future Royalties - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended				6 Months Ended
	Feb. 28, 2017	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Liability Related to Sale of Future Royalties [Line Items]
Liabilities		$ 547,813		$ 420,420		$ 547,813
Non-cash interest expense recognized						5,722	$ 11,638
Change in Accounting Estimate [Member]
Liability Related to Sale of Future Royalties [Line Items]
Imputed rate of interest on unamortized liability			7.00%	15.00%
Non-cash interest expense recognized			$ 2,800	$ 5,700
Reduction in net loss						$ (2,800)
Reduction in net loss per share						$ 0.04
Royalty Purchase Agreement [Member]
Liability Related to Sale of Future Royalties [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		7.00%		15.00%		7.00%
Non-cash interest expense recognized		$ 2,900			$ 5,900	$ 5,700	$ 11,600
Royalty Purchase Agreement [Member] \| Minimum [Member]
Liability Related to Sale of Future Royalties [Line Items]
Percent of royalty on net sale	4.50%
Royalty Purchase Agreement [Member] \| Maximum [Member]
Liability Related to Sale of Future Royalties [Line Items]
Additional percent of royalty on net sale	1.00%

Liability Related to Sale of Future Royalties - Schedule Represents Allocation of Transaction Consideration on a Relative Fair Value Basis to the Liability and the Common Stock (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021
Royalty Liability [Abstract]
Liability related to sale of future royalties beginning balance	$ 168,890	$ 166,068	$ 148,983	$ 143,276	$ 166,068
Interest accretion	2,871	2,795	5,912	5,689
Amortization of issuance costs	29	27	19	18
Liability related to sale of future royalties ending balance	$ 171,790	$ 168,890	$ 154,914	$ 148,983	$ 171,790

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2021 Tranche $ / shares shares	Jun. 30, 2021 USD ($)	Mar. 31, 2020 USD ($) $ / shares shares	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Claims settlement			$ 2,200	$ 0	$ 2,151
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]
Warrants outstanding to purchase upon exercise of common stock \| shares			21,595
Warrants exercise price \| $ / shares			$ 10.42
Warrants expiration date			2030-01
Amortization of discount on debt			$ 200
Performance Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted \| shares	375,000
Per unit weighted average grant date fair value \| $ / shares	$ 25.32
Number of tranche \| Tranche	2
Performance Stock Units \| Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sharebased compensation arrangement by share based payment award award vesting rights percentage	50.00%
Allocated share based compensation expense		$ 700
Performance Stock Units \| Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sharebased compensation arrangement by share based payment award award vesting rights percentage	50.00%
Allocated share based compensation expense		$ 0

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) ft²	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) ft²	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Weighted average remaining lease term	12 years		12 years
Weighted average discount rate	9.80%		9.80%
Operating lease right-of-use assets	$ 83,006		$ 83,006		$ 2,924
Short-term lease liability	12,190		12,190		2,785
Cash paid included in net cash used in operating activities			2,600	$ 3,600
Rent expense	$ 5,300	$ 1,400	$ 6,700	$ 2,800
Current Lease [Member]
Lessee Lease Description [Line Items]
Lease expiration date			Jun. 30, 2022
Weighted average remaining lease term	1 year		1 year
Weighted average discount rate	6.80%		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]
Lease expiration date			Sep. 30, 2033
Weighted average remaining lease term	12 years 3 months 18 days		12 years 3 months 18 days
Weighted average discount rate	9.80%		9.80%
Operating lease, term description			We have two consecutive five-year options to extend the lease.
Area of land under lease agreement \| ft²	234,892		234,892
Operating lease commencement period			2021-03
Operating lease right-of-use assets	$ 77,900		$ 77,900
Short-term lease liability	3,700		3,700
Long-term lease liability	85,300		85,300
Tenant improvement reimbursements	11,100		11,100
Security Deposit Liability					$ 5,100	$ 5,100
Lease agreement allowances for tenant improvements			43,600
Construction in progress	32,400		32,400
Undiscounted lease payments	$ 230,500		$ 230,500

Commitments and Contingencies - Schedule of Undiscounted Future Non-cancellable Lease Payments under the Lease Agreements (Detail) $ in Thousands	Jun. 30, 2021 USD ($)
Leases [Abstract]
2021 remainder	$ 4,133
2022	16,098
2023	17,216
2024	17,668
2025	18,249
Thereafter	163,434
Total undiscounted future lease payments	236,798
Less: Present value adjustments	(128,895)
Total lease liability	$ 107,903

Subsequent Events - Additional Information (Detail) - Underwritten Public Offering [Member] - Subsequent Event [Member] $ / shares in Units, $ in Millions	Jul. 23, 2021 USD ($) $ / shares shares
Subsequent Event [Line Items]
Sales of common stock, number of shared issued \| shares	11,500,000
Sale of stock, price per share \| $ / shares	$ 27.50
Common stock, shares issued \| shares	1,500,000
Gross proceeds, consideration received on transaction \| $	$ 316.3
Net proceeds, consideration received on transaction \| $	$ 297.3