Summit Therapeutics (SMMT) 10-Q1 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Cover

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2024	Apr. 22, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-36866
Entity Registrant Name	Summit Therapeutics Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	37-1979717
Entity Address, Address Line One	601 Brickell Key Drive, Suite 1000
Entity Address, City or Town	Miami
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	33131
City Area Code	650
Local Phone Number	460-8308
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	SMMT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		701,979,596
Entity Central Index Key	0001599298
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 61,294	$ 71,425
Restricted cash	317	0
Short-term investments	95,386	114,817
Prepaid expenses and other current assets	5,323	2,622
Research and development tax credit receivable	945	848
Total current assets	163,265	189,712
Non-current assets:
Property and equipment, net	181	204
Right-of-use assets	9,373	5,859
Goodwill	1,875	1,893
Research and development tax credit receivable	212	959
Other assets	1,875	4,322
Total assets	176,781	202,949
Current liabilities:
Accounts payable	6,371	2,667
Accrued liabilities	6,547	8,783
Accrued compensation	6,033	5,429
Lease liabilities	3,699	2,809
Other current liabilities	788	717
Total current liabilities	23,438	20,405
Non-current liabilities:
Lease liabilities, net of current portion	5,823	3,290
Other non-current liabilities	3,310	1,562
Promissory note payable to a related party	100,000	100,000
Total liabilities	$ 132,571	$ 125,257
Notes Payable, Noncurrent, Related and Nonrelated Party Status [Extensible Enumeration]	Related Party	Related Party
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.01 par value, 20,000,000 shares authorized; none issued and outstanding at March 31, 2024 and December 31, 2023, respectively	0	0
Common stock, $0.01 par value: 1,000,000,000 shares authorized; 701,974,596 and 701,660,053 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	7,020	7,017
Additional paid-in capital	1,076,370	1,066,381
Accumulated other comprehensive loss	(2,449)	(2,448)
Accumulated deficit	(1,036,731)	(993,258)
Total stockholders' equity	44,210	77,692
Total liabilities and stockholders' equity	$ 176,781	$ 202,949

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	701,974,596	701,660,053
Common stock, shares outstanding (in shares)	701,974,596	701,660,053

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating expenses:
Research and development	$ 30,873	$ 9,883
In-process research and development	0	520,915
General and administrative	11,729	6,940
Total operating expenses	42,602	537,738
Other operating income, net	213	584
Operating loss	(42,389)	(537,154)
Other expense, net	(1,084)	(5,222)
Net loss	$ (43,473)	$ (542,376)
Net loss per share:
Basic (in dollars per share)	$ (0.06)	$ (1.43)
Diluted (in dollars per share)	$ (0.06)	$ (1.43)
Weighted-average shares used to compute net loss per share:
Basic (in shares)	701,785,250	378,163,980
Diluted (in shares)	701,785,250	378,163,980
Comprehensive loss:
Net loss	$ (43,473)	$ (542,376)
Other comprehensive (loss) income:
Foreign currency translation adjustments	(12)	(51)
Reclassification of cumulative currency translation gain to other expense, net	0	(419)
Net changes related to short-term investments	11	968
Comprehensive loss	$ (43,474)	$ (541,878)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022		211,091,425
Beginning balance at Dec. 31, 2022	$ 126,654	$ 2,110	$ 504,767	$ (1,893)	$ (378,330)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock purchase plans and exercise of stock options (in shares)		403,469
Issuance of common stock under stock purchase plans and exercise of stock options	651	$ 4	647
Rights offering of common stock, net of offering costs (in shares)		476,190,471
Rights offering of common stock, net of offering costs	499,381	$ 4,762	494,619
Issuance of common stock in lieu of cash for Akeso upfront payment (in shares)		10,000,000
Issuance of common stock in lieu of cash for Akeso upfront payment	45,900	$ 100	45,800
Stock-based compensation	2,775		2,775
Net other comprehensive (loss) income	497			497
Net loss	(542,376)				(542,376)
Ending balance (in shares) at Mar. 31, 2023		697,685,365
Ending balance at Mar. 31, 2023	$ 133,482	$ 6,976	1,048,608	(1,396)	(920,706)
Beginning balance (in shares) at Dec. 31, 2023	701,660,053	701,660,053
Beginning balance at Dec. 31, 2023	$ 77,692	$ 7,017	1,066,381	(2,448)	(993,258)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock purchase plans and exercise of stock options (in shares)		314,543
Issuance of common stock under stock purchase plans and exercise of stock options	485	$ 3	482
Stock-based compensation	9,507		9,507
Net other comprehensive (loss) income	(1)			(1)
Net loss	$ (43,473)				(43,473)
Ending balance (in shares) at Mar. 31, 2024	701,974,596	701,974,596
Ending balance at Mar. 31, 2024	$ 44,210	$ 7,020	$ 1,076,370	$ (2,449)	$ (1,036,731)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Statement of Stockholders' Equity [Abstract]
Offering costs	$ 619

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (43,473)	$ (542,376)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash interest expense	0	6,063
Amortization of discount on short-term investments	(402)	0
Unrealized foreign exchange loss (gain)	9	(470)
Reclassification of currency translation gain	0	(419)
Impairment of fixed assets	0	474
Depreciation	27	90
Stock-based compensation	9,507	2,775
In-process research and development	0	520,915
Change in operating assets and liabilities:
Accounts receivable	0	350
Prepaid expenses	(2,792)	331
Other current and long-term assets	2,531	508
Research and development tax credit receivable	632	850
Accounts payable	3,704	308
Accrued liabilities	(2,154)	730
Other long- term liabilities	1,763	0
Accrued compensation	606	(3,238)
Operating lease right-of-use assets and lease liabilities, net	(92)	(22)
Net cash used in operating activities	(30,134)	(13,131)
Cash flows from investing activities:
Purchases of property and equipment	(4)	(53)
Purchase of short-term investments	(92,982)	(169,995)
Maturities and sales of short-term investments	112,857	0
Payments to Akeso for upfront milestone payments and associated direct transaction costs	0	(475,015)
Net cash provided by (used in) investing activities	19,871	(645,063)
Cash flows from financing activities:
Proceeds from the issuance of common stock for rights offering	0	104,686
Transaction costs related to the issuance of common stock for rights offering	0	(539)
Repayment of related party promissory notes	0	(24,686)
Proceeds received related to employee stock awards	485	651
Net cash provided by financing activities	485	80,112
Effect of exchange rate changes on cash	(36)	444
Decrease in cash and cash equivalents	(9,814)	(577,638)
Cash, cash equivalents and restricted cash at beginning of period	71,425	648,607
Cash, cash equivalents and restricted cash at end of period	61,611	70,969
Supplemental Disclosure of Cash Flow Information:
Cash paid for interest on related party promissory notes	1,501	1,306
Transaction costs included in accrued expenses	0	80
Lease assets obtained in exchange for operating lease liabilities	4,216	0
Rights offering
Issuance of common stock	0	395,314
Akeso License Agreement
Issuance of common stock	$ 0	$ 45,900

Nature of Business and Operatio

Nature of Business and Operations	3 Months Ended
Nature of Business and Operations	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Operations	Nature of Business and Operations Nature of Business and Operations Summit Therapeutics Inc. (“we”, “Summit” or the “Company”) is a biopharmaceutical company focused on the discovery, development, and commercialization of patient-, physician-, caregiver- and societal-friendly medicinal therapies intended to improve quality of life, increase potential duration of life, and resolve serious unmet medical needs. The Company’s current lead development candidate is ivonescimab, a novel, potential first-in-class bispecific antibody intending to combine the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects of an anti-VEGF compound into a single molecule. On December 5, 2022, the Company entered into a Collaboration and License Agreement (the “License Agreement”) with Akeso, Inc. and its affiliates (“Akeso”) pursuant to which the Company has in-licensed ivonescimab as further described in Note 7 . Through the License Agreement, the Company obtained the rights to develop and commercialize ivonescimab in the United States, Canada, Europe, and Japan (the “Licensed Territory”). The License Agreement and transaction closed in January 2023 following customary waiting periods. The Company’s operations will be focused on the development of ivonescimab and other future activities, as the Company determines. The Company has begun its development for ivonescimab in non-small cell lung cancer (“NSCLC”), specifically launching Phase III clinical trials in the following indications: a) ivonescimab combined with chemotherapy in patients with epidermal growth factor receptor (“EGFR”)-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with a third-generation EGFR tyrosine kinase inhibitor (“TKI”) (“HARMONi”); and b) ivonescimab combined with chemotherapy in first-line metastatic squamous NSCLC patients (“HARMONi-3”) As of the date of these financial statements, both studies are enrolling patients. The entry into the License Agreement with Akeso represents a significant change in the Company’s strategy and its future operations will be focused on the development of ivonescimab and other future activities as the Company determines. The Company’s portfolio also includes ridinilazole, a product candidate for treating patients suffering from Clostridioides difficile infection, also known as C. difficile infection, or CDI, and SMT-738, the first of a novel class of precision antibiotics for combating multidrug resistant infections, specifically carbapenem-resistant Enterobacteriaceae (“CRE”) infections. All prior development activities related to ridinilazole and SMT-738 have been terminated; the Company will continue to pursue partnerships for both assets.

Basis of Presentation and Use o

Basis of Presentation and Use of Estimates	3 Months Ended
Basis of Presentation and Use of Estimates	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission. Accordingly, certain information and disclosures required by U.S. GAAP for complete consolidated financial statements are not included herein. All intercompany accounts and transactions have been eliminated in consolidation. The interim financial data as of March 31, 2024 and for the three months ended March 31, 2024 are unaudited; however, in the opinion of management, the interim data includes all adjustments, consisting of normal recurring adjustments, necessary for a fair statement of the results for the interim periods. The condensed consolidated balance sheet presented as of December 31, 2023 has been derived from the consolidated audited financial statement as of that date. The results of the period are not necessarily indicative of full year results or any other interim period. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto of the Company which are included in the Company's Annual Report on Form 10-K for the year ended December 31, 2023 filed with the Securities and Exchange Commission on February 20, 2024. The financial results of the Company's activities are reported in United States Dollars Our accounting policies are consistent with the Notes to the Consolidated Financial Statement in the Company's Annual Report on Form 10-K filed with the Securities and Exchange Commission, except as updated below: Cash Equivalents Cash equivalents consist of non-interest-bearing deposits denominated in the U.S. dollar and British pound, and the Company invested cash in money market funds and U.S. treasury securities. All highly liquid investments with a maturity date of 90 days or less at the date of purchase are considered to be cash equivalents. The appropriate classification of investments in securities as to whether it is classified as a cash equivalent is determined by the Company at the time of purchase. Marketable Securities Marketable securities consist of investments with original maturities greater than ninety days from the date of acquisition. The Company classifies investments with maturities of greater than 90 days as short-term, based on the liquid nature of the securities and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of investments as available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices or other observable inputs. Unrealized gains and losses are recorded as a component of other comprehensive income (loss). Realized gains and losses are determined on a specific identification basis and are included in other (expense) income. Amortization and accretion of discounts and premiums is also recorded in other (expense) income. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made, this estimate is limited to the amount by which fair value is less than amortized cost. The credit-related impairment amount is recognized in the condensed consolidated statements of operations and comprehensive loss and the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive income (loss) in shareholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of the allowance account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis the allowance for credit loss is written off and the excess of the amortized cost basis of the asset over its fair value is recorded in the condensed consolidated statements of operations and comprehensive loss.. Use of Estimates The preparation of these unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the date of the unaudited condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going basis, management evaluates its estimates and judgments, including those related to accrued research and development expenses, stock-based compensation, goodwill, other long-lived assets and income taxes. Management bases its estimates and judgments on historical experience and on various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

Summary of Significant Accounti

Summary of Significant Accounting Policies and Recently Issued or Adopted Accounting Pronouncements	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Recently Issued or Adopted Accounting Pronouncements	Summary of Significant Accounting Policies and Recently Issued or Adopted Accounting Pronouncements Summary of Accounting Policies The significant accounting policies used in the preparation of these condensed consolidated financial statements for the three months ended March 31, 2024 are consistent with those discussed in Note 4 to the consolidated financial statements in the Company's Annual Report on Form 10-K for the year ended December 31, 2023. Recently Issued or Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies that the Company adopts as of the specified effective date. The Company does not believe that the adoption of recently issued standards have or may have a material impact on the accompanying unaudited condensed consolidated financial statements.

Liquidity and Capital Resources

Liquidity and Capital Resources	3 Months Ended
Liquidity and Capital Resources	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Liquidity and Capital Resources	Liquidity and Capital Resources During the three months ended March 31, 2024, the Company incurred a net loss of $43,473 and cash flows used in operating activities for the three months ended March 31, 2024 was $30,134. As of March 31, 2024, the Company had an accumulated deficit of $1,036,731, cash and cash equivalents of $61,294, short-term investments in U.S. treasury securities of $95,386 and current and long-term U.K. research and development tax credits receivable of $1,157. The Company expects to continue to generate operating losses for the foreseeable future. The Company has evaluated whether its cash, cash equivalents and U.K. research and development tax credits provide sufficient cash to fund its operating cash needs for the next twelve months from the date of issuance of these quarterly financials. The Company is investing in the clinical development of ivonescimab, including its ongoing clinical trials. In addition, the Company has a $100,000 promissory note and interest payable to a related party (refer to Note 14 for further details) that matures on April 1, 2025. In order to repay this promissory note, the Company intends to raise additional capital. As of the date of issuance of these condensed consolidated financial statements, additional capital has not yet been secured. These conditions raise substantial doubt about the Company’s ability to continue as a going concern for at least one year from the date these condensed consolidated financial statements are issued. Until the Company can generate substantial revenue and achieve profitability, the Company will need to raise additional capital to fund its ongoing operations and capital needs. The Company continues to evaluate options to further finance its operating cash needs for its product candidates through a combination of some, or all, of the following: equity and debt offerings, collaborations, strategic alliances, grants and clinical trial support from government entities, philanthropic, non-government and not-for-profit organizations, and marketing, distribution or licensing arrangements. There is no assurance, however, that additional financing will be available when needed or that management of the Company will be able to obtain financing on terms acceptable to the Company. If the Company is unable to obtain funding when required in the future, the Company could be required to delay, reduce, or eliminate research and development programs, product portfolio expansion, or future commercialization efforts, which could adversely affect its business prospects. The accompanying condensed consolidated financial statements are prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and satisfaction of liabilities in the normal course of the business. The condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classifications of liabilities that might result from the outcome of this uncertainty.

Segment Reporting

Segment Reporting	3 Months Ended
Segment Reporting	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company's chief operating decision makers (the "CODM function"), which are the Company's CEOs, Mr. Duggan and Dr. Zanganeh, utilize consolidated financial information to make decisions about allocating resources and assessing performance for the entire Company. The CODM function approves of key operating and strategic decisions, including key decisions in clinical development and clinical operating activities, entering into significant contracts, such as revenue contracts and collaboration agreements and approves the Company's consolidated operating budget. The CODM function views the Company's operations and manages its business as a single reportable operating segment. The Company's single operating segment covers the Company’s research and development activities, primarily comprising of oncology product research activities (including ivonescimab). As the Company operates as one operating segment, all required financial segment information can be found in these condensed consolidated financial statements. The Company operates in two geographic regions: the U.K. and the U.S. The following table summarizes the Company's long-lived assets, which include the Company's property and equipment, net and right-of-use assets by geography: March 31, 2024 December 31, 2023 United Kingdom $ 742 $ 808 United States (1) 8,812 5,254 $ 9,554 $ 6,062 (1) The increase in long-lived assets as of March 31, 2024 as compared to December 31, 2023, is primarily due to $4,106 of net right-of use assets recorded as a result of the Company entering into a new lease agreement for their Miami, FL headquarters, partially offset by $534 of amortization expense for right-of-use assets relating to lease agreements for its office space in Menlo Park, CA.

Other Operating Income, Net

Other Operating Income, Net	3 Months Ended
Other Operating Income, Net	Mar. 31, 2024
Other Income and Expenses [Abstract]
Other Operating Income, Net	Other Operating Income, net The following table sets forth the components of other operating income, net by category: Three Months Ended Other operating income, net by category: 2024 2023 Research and development tax credits 213 542 Grant income from CARB-X (as defined below) — 34 Other income — 8 $ 213 $ 584 Research and development tax credits Income from tax credits, consist of R&D tax credits received in the U.K. The Company benefits from the Small and Medium Enterprise Program ("SME Program") U.K. research and development tax credit cash rebate regime, and The Research and Development Expenditure Credit ("The RDEC scheme"), a UK government tax incentive that promotes innovation amongst UK's larger businesses. Qualifying expenditures largely comprise of employment costs for research staff, consumables, a proportion of relevant, permitted sub-contract costs and certain internal overhead costs incurred as part of research projects for which the Company does not receive income. Tax credits related to the SME Program and The RDEC scheme are recorded as other operating income in the consolidated statements of operations and other comprehensive loss. Under these scheme, the Company receives cash payments that are not dependent on the Company’s pre-tax net income levels. Based on criteria established by His Majesty’s Revenue and Customs ("HMRC"), a portion of expenditures being carried out in relation to the Company's pipeline research and development, clinical trials management and third-party manufacturing development activities are eligible for the SME regime and the Company expects such elements of research and development expenditure incurred in its UK entities will also continue to be eligible for the SME regime for future periods. As of March 31, 2024, the current and non-current research and development tax credit receivable was $945 and $212, respectively. As of December 31, 2023, the current and non-current research and development tax credit receivable was $848 and $959, respectively. CARB-X (as defined below)

Akeso Collaboration and License

Akeso Collaboration and License Agreement	3 Months Ended
Akeso Collaboration and License Agreement	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Akeso Collaboration and License Agreement	Akeso Collaboration and License Agreement On December 5, 2022, the Company entered into a Collaboration and License Agreement (the “License Agreement”) with Akeso, Inc. and its affiliates (“Akeso”) pursuant to which the Company is in-licensing its breakthrough bispecific antibody, ivonescimab. The License Agreement and transaction closed in January 2023 following customary waiting periods. Ivonescimab, known as AK112 in China and Australia, and also as SMT112 in the United States, Canada, Europe, and Japan, is a novel, potential first-in-class bispecific antibody intending to combine the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects of an anti-VEGF into a single molecule. Ivonescimab was engineered to bring two well established oncology targeted mechanisms together. Ivonescimab is currently in clinical development and, pursuant to the terms of the License Agreement, Summit will design and conduct the clinical trial activities to support regulatory filings in the Licensed Territory that Summit will submit. Pursuant to the terms of the License Agreement, Summit will have final decision-making authority with respect to clinical development strategy and execution in the Licensed Territory. For co-joined studies in which both Summit and Akeso participate, mutual agreement is required for material decisions; Summit retains the exclusive decision making with respect to participating in, and continuing its participation in, co-joined studies. Pursuant to the terms of the License Agreement, Summit will have final decision making authority with respect to commercial strategy, pricing and reimbursement and other commercialization matters in the Licensed Territory. In connection with the License Agreement, the Company has also entered into a Supply Agreement with Akeso, pursuant to which Summit agrees to purchase a certain portion of drug substance for clinical and commercial supply. Summit is not assuming any liabilities (including contingent liabilities), acquiring any physical assets or trade names, or hiring or acquiring any employees from Akeso in connection with the License Agreement. Through the License Agreement, the Company obtained the rights to develop and commercialize ivonescimab in the United States, Canada, Europe, and Japan (the “Licensee Territory”). In exchange for the rights obtained, an upfront payment of $500,000 was made to Akeso, of which $274,900 was paid in cash and, pursuant to the License Agreement and Issuance Agreement, Akeso elected to receive 10,000,000 shares of the Company's common stock in lieu of $25,100 cash. The remaining $200,000 amount of the upfront payment was paid on March 6, 2023. The Company has accounted for the License Agreement to acquire the rights to develop and commercialize ivonescimab as the acquisition of an asset. All of the consideration relates to ivonescimab and technological feasibility of the asset has not yet been established since ivonescimab is in clinical development. As such, the Company has expensed the consideration as in-process research and development upon closing of the transaction in the condensed consolidated statement of comprehensive loss. In-process research and development expense for the three months ended March 31, 2023 was $520,915, which is comprised of the $474,900 paid in cash, the fair value of the 10,000,000 shares of common stock on the date of closing the transaction of $45,900, and $115 of direct transactions costs incurred.

Other Expense, net

Other Expense, net	3 Months Ended
Other Expense, net	Mar. 31, 2024
Other Income and Expenses [Abstract]
Other Expense, net	Other Expense, net The following table sets forth the components of other (expense) income: Three Months Ended March 31, 2024 2023 Foreign currency gains $ 208 $ 508 Interest expense on promissory notes payable to related parties (3,121) (8,327) Investment income 1,829 1,761 Reclassification of cumulative currency translation gain (1) — 419 Other expense, net — 417 $ (1,084) $ (5,222) (1) During the three months ended March 31, 2023, the Company dissolved certain dormant entities and as a result, $419 of cumulative foreign currency translation adjustments were re-classified from accumulated other comprehensive loss relating to these entities. For the three months ended March 31, 2024, other expense, net primarily consisted of loan interest expense incurred related to the $100,000 promissory note and for the three months ended March 31, 2023, other expense, net primarily consisted of loan interest expense incurred related to the $520,000 promissory notes, as described in Note 14. These amounts for both periods are partially offset by investment income related to the Company's money market funds and short-term investments in U.S. treasury securities.

Net Loss per Share

Net Loss per Share	3 Months Ended
Net Loss per Share	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share The following table sets forth the computation of basic and diluted net loss per share: Three Months Ended 2024 2023 Net loss $ (43,473) $ (542,376) Basic weighted average number of shares of common stock outstanding 701,785,250 378,163,980 Diluted weighted average number of shares of common stock outstanding 701,785,250 378,163,980 Basic net loss per share $ (0.06) $ (1.43) Diluted net loss per share $ (0.06) $ (1.43) Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the diluted net loss by the weighted-average number of common shares outstanding for the period, including potentially dilutive common shares. Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share for all periods, as the inclusion of all potential common share equivalents outstanding would have been anti-dilutive. The following potentially dilutive securities were excluded from the computation of the diluted net loss per share of common stock for the periods presented because their effect would have been anti-dilutive: March 31, 2024 2023 Options to purchase common stock 54,851,855 20,179,822 Warrants 5,015,642 5,821,137 Shares expected to be purchased under employee stock purchase plan 127,978 206,772 59,995,475 26,207,731 Stock options that are outstanding and contain performance-based or market-based vesting criteria for which the performance or market conditions have not been met are excluded from the presentation of common stock equivalents outstanding in the chart above

Fair Value Measurements and Sho

Fair Value Measurements and Short-Term Investments	3 Months Ended
Fair Value Measurements and Short-Term Investments	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements and Short-Term Investments	Fair Value Measurements and Short-Term Investments In accordance with the provisions of fair value accounting, a fair value measurement assumes that the transaction to sell an asset or transfer a liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability and defines fair value based on the exit price model. The fair value measurement guidance establishes a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The guidance describes three levels of inputs that may be used to measure fair value: Level 1 Quoted prices in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments or securities or derivative contracts that are valued using a pricing model with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the Company categorizes such assets and liabilities based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset. The following tables sets forth the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023: Fair Value Measurements as of March 31, 2024 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 16,946 $ — $ — $ 16,946 U.S. Government treasury bills — 40,157 — 40,157 Short-term investments: . U.S. Government treasury bills — 95,386 — 95,386 Total financial assets $ 16,946 $ 135,543 $ — $ 152,489 Fair Value Measurements as of December 31, 2023 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 21,016 $ — $ — $ 21,016 U.S. Government treasury bills — 39,341 — 39,341 Short-term investments U.S. Government treasury bills — 114,817 — 114,817 Total financial assets $ 21,016 $ 154,158 $ — $ 175,174 The tables above do not include cash at March 31, 2024 and December 31, 2023 of $4,191 and $11,068, respectively. The Company believes that the carrying amounts of prepaid expenses, other current assets, accounts payable, and accrued expenses approximates their fair values due to the short-term nature of those instruments. The carrying value of the Company’s promissory note approximates its fair value and the current interest rate of the note outstanding when compared to market interest rates (which represents a Level 2 measurement). Refer to Note 14 for further details. The following table sets forth the Company’s short-term investments as of March 31, 2024 and December 31, 2023, which have a contractual maturity of less than one year: March 31, 2024 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Credit (Loss) Fair Value Assets U.S. Government treasury bills $ 95,375 $ 11 $ — $ 95,386 Total $ 95,375 $ 11 $ — $ — $ 95,386 December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Credit (Loss) Fair Value Assets U.S. Government treasury bills $ 114,781 $ 36 $ — $ — $ 114,817 Total $ 114,781 $ 36 $ — $ — $ 114,817

Goodwill

Goodwill	3 Months Ended
Goodwill	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Goodwill As of March 31, 2024 and December 31, 2023, goodwill was $1,875 and $1,893, respectively. Changes in the gross carrying amount of goodwill during the three months ended March 31, 2024 as compared to December 31, 2023, are the result of changes in foreign currency. As of December 31, 2023, the Company performed its annual impairment assessment of goodwill and determined that it is more likely than not that the fair value of the reporting unit exceeds its carrying amount. There have been no cumulative goodwill impairments recognized during the three months ended March 31, 2024.

Leases

Leases	3 Months Ended
Leases	Mar. 31, 2024
Leases [Abstract]
Leases	Leases The Company has operating leases for real estate. The Company does not have any finance leases. During the three months ended March 31, 2024, the Company recorded $4,216 of additional right-of-use assets related to a new lease for office space that commenced during the period for its Miami, Florida headquarter location. Total future lease payments as of March 31, 2024, which include base rent and sales tax are approximately $4,814 on an undiscounted basis. This lease commenced on February 1, 2024 and has a term of 64 months. As of March 31, 2024 the Company has $317 of restricted cash associated with an irrevocable letter of credit required by the landlord to enter into this lease. There were no new right-of-use assets recorded during the three month period ended March 31, 2023. The carrying value of the right-of-use assets as of March 31, 2024 and December 31, 2023 was $9,373 and $5,859, respectively.

Research and Development Prepai

Research and Development Prepaid Expenses and Accrued Liabilities	3 Months Ended
	Mar. 31, 2024
Research and Development [Abstract]
Research and Development Prepaid Expenses and Accrued Liabilities	Research and Development Prepaid Expenses and Accrued Liabilities Included within prepaid expenses and other current assets at March 31, 2024 and December 31, 2023 is $4,351 and $1,466, respectively, of prepayments relating to research and development expenditures. Included within accrued liabilities at March 31, 2024 and December 31, 2023 is $6,074 and $7,289, respectively, relating to research and development expenditures. These amounts are determined based on the estimated costs to complete each study or activity, the estimation of the current stage of completion and the invoices received, as well as predetermined milestones which are not reflective of the current stage of development for prepaid expenses. However, prepaid expenses decrease and accrued liabilities increase as the activities progress, and if actual costs incurred exceed the prepaid expense, an accrual will be recorded for the liability. The key sensitivity is the estimated current stage of completion of each study or activity, which is based on information received from the supplier and the Company’s operational knowledge of the work completed under those contracts.

Promissory Note Payable to Rela

Promissory Note Payable to Related Parties	3 Months Ended
Promissory Note Payable to Related Parties	Mar. 31, 2024
Related Party Transactions [Abstract]
Promissory Note Payable to Related Parties	Promissory Note Payable to Related Parties Non-current promissory note payable to related parties was $100,000 as of March 31, 2024 and December 31, 2023. December 2022 Promissory Note On December 6, 2022, the Company entered into a Note Purchase Agreement (the "Note Purchase Agreement"), with Mr. Duggan and Dr. Zanganeh, pursuant to which the Company agreed to sell to each of Mr. Duggan and Dr. Zanganeh unsecured promissory notes in the aggregate amount of $520,000. Pursuant to the Note Purchase Agreement, the Company issued to Mr. Duggan and Dr. Zanganeh unsecured promissory notes in the amount of $400,000 (the "Duggan February Note") and $20,000 (the "Zanganeh Note"), respectively, which would mature and become due on February 15, 2023 and an unsecured promissory note to Mr. Duggan in the amount of $100,000 (the “Duggan September Note” and together with the Duggan February Note and the Zanganeh Note, the “December 2022 Notes”), which was originally due on September 15, 2023. The maturity dates of the December 2022 Notes could be extended one or more times at the Company’s election, but in no event to a date later than September 6, 2024. In addition, if the Company consummates a public offering, then upon the later to occur of (i) five On January 19, 2023, the Company provided notice to extend the term of the Duggan February Note and Duggan September Note to a maturity date of September 6, 2024. Furthermore, on January 19, 2023, the Company and Mr. Duggan rectified the Duggan February Note and Duggan September Note in order to correctly reflect the parties’ intent that the Company may only prepay (i) the Duggan February Note following the completion of a public rights offering to be conducted by Summit in the approximate amount of $500,000, or a similar capital raise, in an amount equal to the lesser of (x) the net proceeds of the Rights Offering or such capital raise or (y) the full amount outstanding of the Duggan February Note, and (ii) Duggan September Note following the completion of a capital raising transaction subsequent to the 2023 Rights Offering in an amount equal to the lesser of (A) the net proceeds of such capital raise or (B) the full amount outstanding of the Duggan September Note. Following the issuance of the two new Promissory Notes (the “Duggan Promissory Notes”), the Duggan February Note and Duggan September Note were marked as “cancelled” on their face and replaced in their entirety by the Duggan Promissory Notes (together with the Zanganeh Note, the "Notes"). On February 15, 2023, the $20,000 Zanganeh Note matured and the Company repaid the outstanding principal balance. In connection with the closing of the 2023 Rights Offering, the $400,000 Duggan Promissory Note matured and became due, and the Company satisfied all principal and accrued interest thereunder using a combination of a portion of the cash proceeds from the 2023 Rights Offering and the extinguishment of a portion of the amount due equal to the subscription price for shares subscribed by Mr. Duggan in the 2023 Rights Offering. The Notes accrued interest at an initial rate of 7.5%. All interest on the Notes was paid on the date of signing for the period through February 15, 2023. Such prepaid interest was paid in a number of shares of the Company’s common stock, par value $0.01 (“Common Stock”) equal to the dollar amount of such prepaid interest, divided by $0.7913 (the consolidated closing bid price immediately preceding the time the Company entered into the Note Purchase Agreement, plus $0.01), which was 9,720,291 shares. For all applicable periods following February 15, 2023, interest shall accrue on the outstanding principal balance of the Notes at the US prime interest rate, as reported in the Wall Street Journal, plus 50 basis points, as adjusted monthly, for three months immediately following February 15, 2023, and thereafter at the US prime rate plus 300 basis points, as adjusted monthly. Such accrued interest shall be paid in cash, quarterly in arrears, on each of March 31, June 30, September 30 and December 31. Debt issuance costs associated with the Notes were $44 and were capitalized as part of the carrying value of the promissory notes payable to related parties. On February 17, 2024, the Duggan February Note was amended and restated to extend the maturity date from September 6, 2024 to April 1, 2025. For all applicable periods commencing February 17, 2024, interest shall accrue on the outstanding principal balance at the greater of 12% or the US prime interest rate, as reported in the Wall Street Journal plus 350 basis points, as adjusted monthly, compounded quarterly. Interest shall be paid upon maturity of the loan. The debt discount is amortized to interest expense using an effective interest rate method. The effective interest rate of the Duggan February Note and Zanganeh Note was 8.9% and the effective interest rate of the Duggan September Note is 12.4%. During the three months ended March 31, 2024 and 2023, the Company incurred interest expense of $3,121 and $8,327, respectively. Interest expense incurred during the three months ended March 31, 2023 included amortized imputed interest of $761. As of March 31, 2024, accrued interest was $1,740 and was recorded in other long-term liabilities. As of December 31, 2023, accrued interest was $120 and was recorded in accrued liabilities. The estimated future principal payments are $0 and $100,000 for 2024 and 2025, respectively, as the note matures on April 1, 2025. July 25, 2022 First Amendment to Sublease Agreement with Maky Zanganeh and Associates, Inc. On July 25, 2022 the Company entered into a first amendment, dated July 19, 2022, to its existing sublease agreement with Maky Zanganeh and Associates, Inc. ("MZA"), consisting of 4,500 square feet of office space at 2882 Sand Hill Road, Menlo Park, California. The existing sublease term, which was set to expire on September 30, 2022, was extended for a period of thirty-nine months from October 1, 2022 through December 31, 2025. The rent payable under the terms of the sublease is equivalent to the proportionate share of the net payable by MZA to the third-party landlord, based on the square footage of office space sublet by the Company, and no mark-up has been applied. During the three months ended March 31, 2024 and 2023, payments of $195 and $189, respectively, were made pursuant to the first amendment to the Sublease Agreement. July 29, 2022 Second Amendment to Sublease Agreement with Maky Zanganeh and Associates, Inc. On July 29, 2022, the Company entered into a second amendment, dated August 1, 2022, to its existing sublease agreement with MZA, described above. The second amendment was effective as of August 1, 2022 and expires on December 31, 2025. The second amendment includes an additional 1,277 square feet (the "Expansion Premises") of office space at 2882 Sand Hill Road, Menlo Park, California. The rent payable under the terms of the sublease is equivalent to the proportionate share of the net payable by MZA to the third-party landlord, based on the square footage of office space sublet by the Company, and no mark-up has been applied. During the three months ended March 31, 2024 and 2023, payments of $55 and $54 respectively, were made pursuant to the second amendment to the Sublease Agreement. December 6, 2022 Note Purchase Agreement Refer to Note 14 for a discussion of the promissory note payable to a related party. Akeso License Agreement Upon the closing of the License Agreement, the Board of Directors (the “Board”) of the Company appointed Dr. Yu (Michelle) Xia to serve as a member of the Board pursuant to the terms of the License Agreement. Dr. Xia is the founder of Akeso, Inc. ("Akeso"), and has been the chairwoman, president and CEO of Akeso since its inception in 2012. For details on the License Agreement, see Note 7. Furthermore, in connection with the License Agreement, the Company also entered into a Supply Agreement with Akeso, pursuant to which Summit agreed to purchase a certain portion of drug substance for clinical and commercial supply (the “Supply Agreement”). 2023 Rights Offering On December 6, 2022, the Company announced a rights offering for its existing shareholders to participate in the purchase of additional shares of its Common Stock for $1.05 per share. The 2023 Rights Offering commenced on February 7, 2023 and the associated subscription rights expired on March 1, 2023. Aggregate gross proceeds from the 2023 Rights Offering were $500,000 from the sale of 476,190,471 shares of the Company's common stock and issuance costs were $619. Mr. Duggan and Dr. Zanganeh fully subscribed to their respective basic subscription rights at a price of $1.05 per share. To satisfy the $395,314 subscription price for the shares subscribed by Mr. Duggan in the 2023 Rights Offering, Mr. Duggan agreed with the Company to extinguish a portion of the amount due and payable to him by the Company at the closing of the 2023 Rights Offering pursuant to the $400,000 Duggan Promissory Note in an amount equal to the subscription price. Private Placement On October 16, 2023, the Company announced the appointment of Mr. Manmeet Soni as its Chief Operating Officer, effective immediately. Mr. Soni has been a part of the Company's Board of Directors since 2019. He will remain a member of the Board of Directors. In conjunction with his appointment, Mr. Soni entered into a share purchase agreement with the Company to invest $5,000 in shares of common stock via a private placement. The transaction was effective October 13, 2023 with a closing price of $1.68, resulting in the purchase of 2,976,190 shares of the Company's common stock.

Stock-Based Compensation and Wa

Stock-Based Compensation and Warrants	3 Months Ended
Stock-Based Compensation and Warrants	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation and Warrants	Stock-Based Compensation and Warrants The Company currently grants stock options to employees and directors under the 2020 Stock Incentive Plan (the "2020 Plan") and formerly, the Company granted stock options under the 2016 Long Term Incentive Plan (the "2016 Plan"). The 2020 Plan is administered by the Compensation Committee of the Company's Board of Directors. The 2020 Plan is intended to attract and retain employees and directors and provide an incentive for these individuals to assist the Company to achieve long-range performance goals and to enable these individuals to participate in the long-term growth of the Company. On October 12, 2023, the Company's stockholders approved an increase in the number of shares of the Company's common stock issuable under the Plan by 70,000,000 shares. The following table summarizes the Company's time-based stock option activity for the three months ended March 31, 2024: Number of Options Weighted average exercise price Outstanding at December 31, 2023 54,209,289 $ 2.28 Granted 1,503,876 3.49 Forfeited (780,500) 2.51 Exercised (80,810) 1.99 Outstanding at March 31, 2024 54,851,855 $ 2.31 Exercisable at March 31, 2024 6,002,166 $ 4.79 The total intrinsic value of all outstanding time-based stock options and exercisable stock options at March 31, 2024 was $113,727 and $3,146, respectively The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The following table summarizes the Company's performance-based stock option activity for the three months ended March 31, 2024: Number of Options Weighted average exercise price Outstanding at December 31, 2023 46,654,220 $ 1.62 Granted 150,000 $ 3.77 Forfeited (275,000) $ 1.76 Exercised — $ — Outstanding at March 31, 2024 46,529,220 $ 1.63 Exercisable at March 31, 2024 — $ — The total intrinsic value of all performance-based stock options at March 31, 2024 was $117,019. As of March 31, 2024, total unrecognized compensation expense related to performance-based stock options that were deemed probable of vesting was approximately $11,313 which excludes 37,223,376 of unvested performance-based stock options that were deemed not-probable of vesting totaling unrecognized stock-based compensation expense of $44,816. The total stock-based compensation expense included in the Company's condensed consolidated statements of operations and comprehensive loss was as follows: Three Months Ended March 31, 2024 2023 Research and development $ 2,414 $ 1,086 General and administrative 7,093 $ 1,689 Total stock-based compensation expense $ 9,507 $ 2,775 The following summarizes share-based compensation expense associated with each of the Company's stock-based compensation arrangements: Three Months Ended March 31, 2024 2023 Time-based stock options $ 8,115 $ 2,671 Performance-based stock options 1,321 48 Employee stock purchase plan 71 56 Total stock-based compensation expense $ 9,507 $ 2,775 Warrants The Company had outstanding and exercisable 5,015,642 warrants with a weighted average exercise price of $1.57 as of March 31, 2024 and December 31, 2023.

Related Party Transactions

Related Party Transactions	3 Months Ended
Related Party Transactions	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	Promissory Note Payable to Related Parties Non-current promissory note payable to related parties was $100,000 as of March 31, 2024 and December 31, 2023. December 2022 Promissory Note On December 6, 2022, the Company entered into a Note Purchase Agreement (the "Note Purchase Agreement"), with Mr. Duggan and Dr. Zanganeh, pursuant to which the Company agreed to sell to each of Mr. Duggan and Dr. Zanganeh unsecured promissory notes in the aggregate amount of $520,000. Pursuant to the Note Purchase Agreement, the Company issued to Mr. Duggan and Dr. Zanganeh unsecured promissory notes in the amount of $400,000 (the "Duggan February Note") and $20,000 (the "Zanganeh Note"), respectively, which would mature and become due on February 15, 2023 and an unsecured promissory note to Mr. Duggan in the amount of $100,000 (the “Duggan September Note” and together with the Duggan February Note and the Zanganeh Note, the “December 2022 Notes”), which was originally due on September 15, 2023. The maturity dates of the December 2022 Notes could be extended one or more times at the Company’s election, but in no event to a date later than September 6, 2024. In addition, if the Company consummates a public offering, then upon the later to occur of (i) five On January 19, 2023, the Company provided notice to extend the term of the Duggan February Note and Duggan September Note to a maturity date of September 6, 2024. Furthermore, on January 19, 2023, the Company and Mr. Duggan rectified the Duggan February Note and Duggan September Note in order to correctly reflect the parties’ intent that the Company may only prepay (i) the Duggan February Note following the completion of a public rights offering to be conducted by Summit in the approximate amount of $500,000, or a similar capital raise, in an amount equal to the lesser of (x) the net proceeds of the Rights Offering or such capital raise or (y) the full amount outstanding of the Duggan February Note, and (ii) Duggan September Note following the completion of a capital raising transaction subsequent to the 2023 Rights Offering in an amount equal to the lesser of (A) the net proceeds of such capital raise or (B) the full amount outstanding of the Duggan September Note. Following the issuance of the two new Promissory Notes (the “Duggan Promissory Notes”), the Duggan February Note and Duggan September Note were marked as “cancelled” on their face and replaced in their entirety by the Duggan Promissory Notes (together with the Zanganeh Note, the "Notes"). On February 15, 2023, the $20,000 Zanganeh Note matured and the Company repaid the outstanding principal balance. In connection with the closing of the 2023 Rights Offering, the $400,000 Duggan Promissory Note matured and became due, and the Company satisfied all principal and accrued interest thereunder using a combination of a portion of the cash proceeds from the 2023 Rights Offering and the extinguishment of a portion of the amount due equal to the subscription price for shares subscribed by Mr. Duggan in the 2023 Rights Offering. The Notes accrued interest at an initial rate of 7.5%. All interest on the Notes was paid on the date of signing for the period through February 15, 2023. Such prepaid interest was paid in a number of shares of the Company’s common stock, par value $0.01 (“Common Stock”) equal to the dollar amount of such prepaid interest, divided by $0.7913 (the consolidated closing bid price immediately preceding the time the Company entered into the Note Purchase Agreement, plus $0.01), which was 9,720,291 shares. For all applicable periods following February 15, 2023, interest shall accrue on the outstanding principal balance of the Notes at the US prime interest rate, as reported in the Wall Street Journal, plus 50 basis points, as adjusted monthly, for three months immediately following February 15, 2023, and thereafter at the US prime rate plus 300 basis points, as adjusted monthly. Such accrued interest shall be paid in cash, quarterly in arrears, on each of March 31, June 30, September 30 and December 31. Debt issuance costs associated with the Notes were $44 and were capitalized as part of the carrying value of the promissory notes payable to related parties. On February 17, 2024, the Duggan February Note was amended and restated to extend the maturity date from September 6, 2024 to April 1, 2025. For all applicable periods commencing February 17, 2024, interest shall accrue on the outstanding principal balance at the greater of 12% or the US prime interest rate, as reported in the Wall Street Journal plus 350 basis points, as adjusted monthly, compounded quarterly. Interest shall be paid upon maturity of the loan. The debt discount is amortized to interest expense using an effective interest rate method. The effective interest rate of the Duggan February Note and Zanganeh Note was 8.9% and the effective interest rate of the Duggan September Note is 12.4%. During the three months ended March 31, 2024 and 2023, the Company incurred interest expense of $3,121 and $8,327, respectively. Interest expense incurred during the three months ended March 31, 2023 included amortized imputed interest of $761. As of March 31, 2024, accrued interest was $1,740 and was recorded in other long-term liabilities. As of December 31, 2023, accrued interest was $120 and was recorded in accrued liabilities. The estimated future principal payments are $0 and $100,000 for 2024 and 2025, respectively, as the note matures on April 1, 2025. July 25, 2022 First Amendment to Sublease Agreement with Maky Zanganeh and Associates, Inc. On July 25, 2022 the Company entered into a first amendment, dated July 19, 2022, to its existing sublease agreement with Maky Zanganeh and Associates, Inc. ("MZA"), consisting of 4,500 square feet of office space at 2882 Sand Hill Road, Menlo Park, California. The existing sublease term, which was set to expire on September 30, 2022, was extended for a period of thirty-nine months from October 1, 2022 through December 31, 2025. The rent payable under the terms of the sublease is equivalent to the proportionate share of the net payable by MZA to the third-party landlord, based on the square footage of office space sublet by the Company, and no mark-up has been applied. During the three months ended March 31, 2024 and 2023, payments of $195 and $189, respectively, were made pursuant to the first amendment to the Sublease Agreement. July 29, 2022 Second Amendment to Sublease Agreement with Maky Zanganeh and Associates, Inc. On July 29, 2022, the Company entered into a second amendment, dated August 1, 2022, to its existing sublease agreement with MZA, described above. The second amendment was effective as of August 1, 2022 and expires on December 31, 2025. The second amendment includes an additional 1,277 square feet (the "Expansion Premises") of office space at 2882 Sand Hill Road, Menlo Park, California. The rent payable under the terms of the sublease is equivalent to the proportionate share of the net payable by MZA to the third-party landlord, based on the square footage of office space sublet by the Company, and no mark-up has been applied. During the three months ended March 31, 2024 and 2023, payments of $55 and $54 respectively, were made pursuant to the second amendment to the Sublease Agreement. December 6, 2022 Note Purchase Agreement Refer to Note 14 for a discussion of the promissory note payable to a related party. Akeso License Agreement Upon the closing of the License Agreement, the Board of Directors (the “Board”) of the Company appointed Dr. Yu (Michelle) Xia to serve as a member of the Board pursuant to the terms of the License Agreement. Dr. Xia is the founder of Akeso, Inc. ("Akeso"), and has been the chairwoman, president and CEO of Akeso since its inception in 2012. For details on the License Agreement, see Note 7. Furthermore, in connection with the License Agreement, the Company also entered into a Supply Agreement with Akeso, pursuant to which Summit agreed to purchase a certain portion of drug substance for clinical and commercial supply (the “Supply Agreement”). 2023 Rights Offering On December 6, 2022, the Company announced a rights offering for its existing shareholders to participate in the purchase of additional shares of its Common Stock for $1.05 per share. The 2023 Rights Offering commenced on February 7, 2023 and the associated subscription rights expired on March 1, 2023. Aggregate gross proceeds from the 2023 Rights Offering were $500,000 from the sale of 476,190,471 shares of the Company's common stock and issuance costs were $619. Mr. Duggan and Dr. Zanganeh fully subscribed to their respective basic subscription rights at a price of $1.05 per share. To satisfy the $395,314 subscription price for the shares subscribed by Mr. Duggan in the 2023 Rights Offering, Mr. Duggan agreed with the Company to extinguish a portion of the amount due and payable to him by the Company at the closing of the 2023 Rights Offering pursuant to the $400,000 Duggan Promissory Note in an amount equal to the subscription price. Private Placement On October 16, 2023, the Company announced the appointment of Mr. Manmeet Soni as its Chief Operating Officer, effective immediately. Mr. Soni has been a part of the Company's Board of Directors since 2019. He will remain a member of the Board of Directors. In conjunction with his appointment, Mr. Soni entered into a share purchase agreement with the Company to invest $5,000 in shares of common stock via a private placement. The transaction was effective October 13, 2023 with a closing price of $1.68, resulting in the purchase of 2,976,190 shares of the Company's common stock.

Commitment and Contingencies

Commitment and Contingencies	3 Months Ended
Commitment and Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments There were no material changes to the Company's lease commitments that were disclosed in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the Securities and Exchange Commission on February 20, 2024, other than the new lease for the Miami, FL headquarter location as described in Note 12. Debt Commitments Refer to Note 14 for a discussion of the promissory note payable to a related party. Other Commitments The Company enters into contracts in the normal course of business with various third parties for clinical trials, preclinical research studies and testing, manufacturing and other services and products for operating purposes. Most contracts provide for termination upon notice, and therefore are cancellable contracts. The majority of these commitments are due within one year. There have been no material changes to the Company's other contractual commitments that were disclosed in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2023. Indemnifications The Company's certificate of incorporation provides that it will indemnify the directors and officers to the fullest extent permitted by Delaware law. In addition, the Company has entered into indemnification agreements with all of the directors and executive officers. These indemnification agreements may require the Company, among other things, to indemnify each such director or executive officer for some expenses, including attorneys’ fees, judgments, fines, and settlement amounts incurred by him or her in any action or proceeding arising out of his or her service as one of the Company's directors or executive officers. The Company believes the fair value for these indemnification obligations is minimal. Accordingly, the Company has not recognized any liabilities relating to these obligations as of March 31, 2024 and December 31, 2023. Legal Proceedings The Company is not currently subject to any material legal proceedings.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Recently Issued or Adopted Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission. Accordingly, certain information and disclosures required by U.S. GAAP for complete consolidated financial statements are not included herein. All intercompany accounts and transactions have been eliminated in consolidation. The interim financial data as of March 31, 2024 and for the three months ended March 31, 2024 are unaudited; however, in the opinion of management, the interim data includes all adjustments, consisting of normal recurring adjustments, necessary for a fair statement of the results for the interim periods. The condensed consolidated balance sheet presented as of December 31, 2023 has been derived from the consolidated audited financial statement as of that date. The results of the period are not necessarily indicative of full year results or any other interim period. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes thereto of the Company which are included in the Company's Annual Report on Form 10-K for the year ended December 31, 2023 filed with the Securities and Exchange Commission on February 20, 2024. The financial results of the Company's activities are reported in United States Dollars
Cash equivalents	Cash Equivalents Cash equivalents consist of non-interest-bearing deposits denominated in the U.S. dollar and British pound, and the Company invested cash in money market funds and U.S. treasury securities. All highly liquid investments with a maturity date of 90 days or less at the date of purchase are considered to be cash equivalents. The appropriate classification of investments in securities as to whether it is classified as a cash equivalent is determined by the Company at the time of purchase.
Marketable securities	Marketable Securities Marketable securities consist of investments with original maturities greater than ninety days from the date of acquisition. The Company classifies investments with maturities of greater than 90 days as short-term, based on the liquid nature of the securities and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of investments as available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices or other observable inputs. Unrealized gains and losses are recorded as a component of other comprehensive income (loss). Realized gains and losses are determined on a specific identification basis and are included in other (expense) income. Amortization and accretion of discounts and premiums is also recorded in other (expense) income. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made, this estimate is limited to the amount by which fair value is less than amortized cost. The credit-related impairment amount is recognized in the condensed consolidated statements of operations and comprehensive loss and the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive income (loss) in shareholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of the allowance account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis the allowance for credit loss is written off and the excess of the amortized cost basis of the asset over its fair value is recorded in the condensed consolidated statements of operations and comprehensive loss..
Use of Estimates	Use of Estimates The preparation of these unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the date of the unaudited condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going basis, management evaluates its estimates and judgments, including those related to accrued research and development expenses, stock-based compensation, goodwill, other long-lived assets and income taxes. Management bases its estimates and judgments on historical experience and on various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.
Recently Issued or Adopted Accounting Pronouncements	Recently Issued or Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies that the Company adopts as of the specified effective date. The Company does not believe that the adoption of recently issued standards have or may have a material impact on the accompanying unaudited condensed consolidated financial statements.

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
Segment Reporting (Tables)	Mar. 31, 2024
Segment Reporting [Abstract]
Summary of long-lived assets by geography	The following table summarizes the Company's long-lived assets, which include the Company's property and equipment, net and right-of-use assets by geography: March 31, 2024 December 31, 2023 United Kingdom $ 742 $ 808 United States (1) 8,812 5,254 $ 9,554 $ 6,062 (1) The increase in long-lived assets as of March 31, 2024 as compared to December 31, 2023, is primarily due to $4,106 of net right-of use assets recorded as a result of the Company entering into a new lease agreement for their Miami, FL headquarters, partially offset by $534 of amortization expense for right-of-use assets relating to lease agreements for its office space in Menlo Park, CA.

Other Operating Income, Net (Ta

Other Operating Income, Net (Tables)	3 Months Ended
Other Operating Income, Net (Tables)	Mar. 31, 2024
Other Income and Expenses [Abstract]
Schedule of other operating income, net	The following table sets forth the components of other operating income, net by category: Three Months Ended Other operating income, net by category: 2024 2023 Research and development tax credits 213 542 Grant income from CARB-X (as defined below) — 34 Other income — 8 $ 213 $ 584

Other Expense, net (Tables)

Other Expense, net (Tables)	3 Months Ended
Other Expense, net (Tables)	Mar. 31, 2024
Other Income and Expenses [Abstract]
Schedule of other (expense) income, net	The following table sets forth the components of other (expense) income: Three Months Ended March 31, 2024 2023 Foreign currency gains $ 208 $ 508 Interest expense on promissory notes payable to related parties (3,121) (8,327) Investment income 1,829 1,761 Reclassification of cumulative currency translation gain (1) — 419 Other expense, net — 417 $ (1,084) $ (5,222) (1) During the three months ended March 31, 2023, the Company dissolved certain dormant entities and as a result, $419 of cumulative foreign currency translation adjustments were re-classified from accumulated other comprehensive loss relating to these entities.

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
Net Loss per Share (Tables)	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of net loss per share	The following table sets forth the computation of basic and diluted net loss per share: Three Months Ended 2024 2023 Net loss $ (43,473) $ (542,376) Basic weighted average number of shares of common stock outstanding 701,785,250 378,163,980 Diluted weighted average number of shares of common stock outstanding 701,785,250 378,163,980 Basic net loss per share $ (0.06) $ (1.43) Diluted net loss per share $ (0.06) $ (1.43)
Schedule of potentially dilutive securities excluded from the computation of loss per share	The following potentially dilutive securities were excluded from the computation of the diluted net loss per share of common stock for the periods presented because their effect would have been anti-dilutive: March 31, 2024 2023 Options to purchase common stock 54,851,855 20,179,822 Warrants 5,015,642 5,821,137 Shares expected to be purchased under employee stock purchase plan 127,978 206,772 59,995,475 26,207,731

Fair Value Measurements and S_2

Fair Value Measurements and Short-Term Investments (Tables)	3 Months Ended
Fair Value Measurements and Short-Term Investments (Tables)	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of assets measured at fair value on a recurring basis	The following tables sets forth the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023: Fair Value Measurements as of March 31, 2024 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 16,946 $ — $ — $ 16,946 U.S. Government treasury bills — 40,157 — 40,157 Short-term investments: . U.S. Government treasury bills — 95,386 — 95,386 Total financial assets $ 16,946 $ 135,543 $ — $ 152,489 Fair Value Measurements as of December 31, 2023 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 21,016 $ — $ — $ 21,016 U.S. Government treasury bills — 39,341 — 39,341 Short-term investments U.S. Government treasury bills — 114,817 — 114,817 Total financial assets $ 21,016 $ 154,158 $ — $ 175,174
Schedule of short-term investments	The following table sets forth the Company’s short-term investments as of March 31, 2024 and December 31, 2023, which have a contractual maturity of less than one year: March 31, 2024 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Credit (Loss) Fair Value Assets U.S. Government treasury bills $ 95,375 $ 11 $ — $ 95,386 Total $ 95,375 $ 11 $ — $ — $ 95,386 December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Credit (Loss) Fair Value Assets U.S. Government treasury bills $ 114,781 $ 36 $ — $ — $ 114,817 Total $ 114,781 $ 36 $ — $ — $ 114,817

Stock-Based Compensation and _2

Stock-Based Compensation and Warrants (Tables)	3 Months Ended
Stock-Based Compensation and Warrants (Tables)	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of stock option activity	The following table summarizes the Company's time-based stock option activity for the three months ended March 31, 2024: Number of Options Weighted average exercise price Outstanding at December 31, 2023 54,209,289 $ 2.28 Granted 1,503,876 3.49 Forfeited (780,500) 2.51 Exercised (80,810) 1.99 Outstanding at March 31, 2024 54,851,855 $ 2.31 Exercisable at March 31, 2024 6,002,166 $ 4.79 The following table summarizes the Company's performance-based stock option activity for the three months ended March 31, 2024: Number of Options Weighted average exercise price Outstanding at December 31, 2023 46,654,220 $ 1.62 Granted 150,000 $ 3.77 Forfeited (275,000) $ 1.76 Exercised — $ — Outstanding at March 31, 2024 46,529,220 $ 1.63 Exercisable at March 31, 2024 — $ —
Schedule of stock-based compensation expense	The total stock-based compensation expense included in the Company's condensed consolidated statements of operations and comprehensive loss was as follows: Three Months Ended March 31, 2024 2023 Research and development $ 2,414 $ 1,086 General and administrative 7,093 $ 1,689 Total stock-based compensation expense $ 9,507 $ 2,775 The following summarizes share-based compensation expense associated with each of the Company's stock-based compensation arrangements: Three Months Ended March 31, 2024 2023 Time-based stock options $ 8,115 $ 2,671 Performance-based stock options 1,321 48 Employee stock purchase plan 71 56 Total stock-based compensation expense $ 9,507 $ 2,775

Liquidity and Capital Resourc_2

Liquidity and Capital Resources (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net loss	$ 43,473	$ 542,376
Net cash flows used in operating activities	30,134	$ 13,131
Accumulated deficit	1,036,731		$ 993,258
Cash and cash equivalents	61,294		71,425
Short-term investments	95,386		114,817
Current and long-term research and development tax credits	1,157
Promissory note payable to a related party	$ 100,000		$ 100,000

Segment Reporting - Narrative (

Segment Reporting - Narrative (Details)	3 Months Ended
Segment Reporting - Narrative (Details)	Mar. 31, 2024 segment country
Segment Reporting [Abstract]
Number of operating segments \| segment	1
Number of geographic regions in which the Company operates \| country	2

Segment Reporting - Long-lived

Segment Reporting - Long-lived assets by geography (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 9,554	$ 6,062
Right-of-use assets	9,373	5,859
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	742	808
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	8,812	$ 5,254
Florida
Revenues from External Customers and Long-Lived Assets [Line Items]
Right-of-use assets	4,106
California
Revenues from External Customers and Long-Lived Assets [Line Items]
Amortization of operating right-of-use assets	$ 534

Other Operating Income, Net - S

Other Operating Income, Net - Summary by Category (Details) - USD ($) $ in Thousands	3 Months Ended		35 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024
Other Income and Expenses [Abstract]
Research and development tax credits	$ 213	$ 542
Grant income from CARB-X	0	34	$ 2,920
Other income	0	8
Other operating income, net	$ 213	$ 584

Other Operating Income, Net - N

Other Operating Income, Net - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		35 Months Ended
	May 31, 2021	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Dec. 31, 2023
Other Income and Expenses [Abstract]
Current research and development tax credit receivable		$ 945		$ 945	$ 848
Non-current research and development tax credit receivable		212		212	$ 959
Maximum funding value	$ 4,100
Funding increase based on achievement of future milestones	$ 3,700
Income earned		$ 0	$ 34	$ 2,920

Akeso Collaboration and Licen_2

Akeso Collaboration and License Agreement (Details) - USD ($) $ in Thousands		1 Months Ended	2 Months Ended	3 Months Ended
	Mar. 06, 2023	Jan. 31, 2023	Mar. 06, 2023	Mar. 31, 2024	Mar. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
In-process research and development				$ 0	$ 520,915
Issuance of common stock in lieu of cash for Akeso upfront payment					$ 45,900
Collaborative arrangement, transaction with party to collaborative arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangement, upfront payment			$ 500,000
Cash payment for collaborative arrangement, upfront payment			474,900
Collaborative arrangement, direct transaction costs			$ 115
Collaborative arrangement, additional potential milestone payments		$ 4,500,000
Collaborative arrangement, potential regulatory milestone payments		1,050,000
Collaborative arrangement, potential commercial milestone payments		3,450,000
Collaborative arrangement, transaction with party to collaborative arrangement, upfront payment one
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cash payment for collaborative arrangement, upfront payment		$ 274,900
Collaborative arrangement, common stock issued in lieu of cash upfront payment (in shares)		10,000,000
Collaborative arrangement, upfront payment, paid in shares		$ 25,100
Issuance of common stock in lieu of cash for Akeso upfront payment		$ 45,900
Collaborative arrangement, transaction with party to collaborative arrangement, upfront payment two
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cash payment for collaborative arrangement, upfront payment	$ 200,000

Other Expense, net (Details)

Other Expense, net (Details) - USD ($) $ in Thousands	3 Months Ended
Other Expense, net (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023	Dec. 06, 2022
Other Income and Expenses [Abstract]
Foreign currency gains	$ 208	$ 508
Interest expense on promissory notes payable to related parties	(3,121)	(8,327)
Investment income	1,829	1,761
Reclassification of cumulative currency translation gain	0	419
Other expense, net	0	417
Other expense, net	$ (1,084)	$ (5,222)
Note Purchase Agreement \| Chief Executive Officer and Chief Executive Officer and President
Related Party Transaction [Line Items]
Promissory note			$ 520,000
Duggan September Note \| Chief Executive Officer
Related Party Transaction [Line Items]
Promissory note			$ 100,000

Net Loss per Share - Computatio

Net Loss per Share - Computation of net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net loss	$ (43,473)	$ (542,376)
Weighted average number of shares of common stock outstanding
Basic (in shares)	701,785,250	378,163,980
Diluted (in shares)	701,785,250	378,163,980
Basic net loss per share (in dollars per share)	$ (0.06)	$ (1.43)
Diluted net loss per share (in dollars per share)	$ (0.06)	$ (1.43)

Net Loss per Share - Securities

Net Loss per Share - Securities excluded from the computation of net loss per share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	59,995,475	26,207,731
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	54,851,855	20,179,822
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	5,015,642	5,821,137
Shares expected to be purchased under employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	127,978	206,772

Fair Value Measurements and S_3

Fair Value Measurements and Short-Term Investments - Measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 95,386	$ 114,817
Total financial assets	152,489	175,174
U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	95,386	114,817
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	16,946	21,016
U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	40,157	39,341
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	16,946	21,016
Level 1 \| U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Level 1 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	16,946	21,016
Level 1 \| U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	135,543	154,158
Level 2 \| U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	95,386	114,817
Level 2 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Level 2 \| U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	40,157	39,341
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 3 \| U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Level 3 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Level 3 \| U.S. Government treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

Fair Value Measurements and S_4

Fair Value Measurements and Short-Term Investments - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Cash	$ 4,191	$ 11,068

Fair Value Measurements and S_5

Fair Value Measurements and Short-Term Investments - Summary of short-term investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 95,375	$ 114,781
Gross Unrealized Gains	11	36
Gross Unrealized (Losses)	0	0
Credit (Loss)	0	0
Fair Value	95,386	114,817
U.S. Government treasury bills
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	95,375	114,781
Gross Unrealized Gains	11	36
Gross Unrealized (Losses)		0
Credit (Loss)	0	0
Fair Value	$ 95,386	$ 114,817

Goodwill (Details)

Goodwill (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 1,875,000	$ 1,893,000
Cumulative goodwill impairments	$ 0

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	3 Months Ended
Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Additional right-of-use assets recorded	$ 4,216	$ 0
Restricted cash	317		$ 0
Right-of-use assets	9,373		$ 5,859
Florida
Lessee, Lease, Description [Line Items]
Additional right-of-use assets recorded	4,216
Total lease payments	$ 4,814
Lease term	64 months
Right-of-use assets	$ 4,106

Research and Development Prep_2

Research and Development Prepaid Expenses and Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Research and Development [Abstract]
Prepaid research and development expenditures	$ 4,351	$ 1,466
Accrued research and development expenditure	$ 6,074	$ 7,289

Promissory Note Payable to Re_2

Promissory Note Payable to Related Parties (Details) $ / shares in Units, $ in Thousands					3 Months Ended
	Feb. 17, 2024	Feb. 15, 2023 USD ($)	Jan. 19, 2023 USD ($) promissory_note	Dec. 06, 2022 USD ($) $ / shares shares	Mar. 31, 2024 USD ($) $ / shares	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) $ / shares
Related Party Transaction [Line Items]
Non-current promissory note payable to a related party					$ 100,000		$ 100,000
Repayment of promissory notes					$ 0	$ 24,686
Common stock par value (in dollars per share) \| $ / shares				$ 0.01	$ 0.01		$ 0.01
Interest expense					$ 3,121	8,327
Other non-current liabilities					3,310		$ 1,562
Accrued liabilities					$ 6,547		8,783
Chief Executive Officer and Chief Executive Officer and President \| Note Purchase Agreement
Related Party Transaction [Line Items]
Promissory note				$ 520,000
Interest rate				7.50%
Prepaid interest, conversion amount (in dollars per share) \| $ / shares				$ 0.7913
Prepaid interest, conversion amount base (in dollars per share) \| $ / shares				$ 0.01
Common stock issued for prepaid interest (in shares) \| shares				9,720,291
Debt issuance costs				$ 44
Chief Executive Officer and Chief Executive Officer and President \| Note Purchase Agreement \| Variable rate, three months immediately following February 15, 2023 \| Prime rate
Related Party Transaction [Line Items]
Interest rate margin				0.50%
Chief Executive Officer and Chief Executive Officer and President \| Note Purchase Agreement \| Variable rate, thereafter \| Prime rate
Related Party Transaction [Line Items]
Interest rate margin				3%
Chief Executive Officer and Chief Executive Officer and President \| Duggan February Note and Zanganeh Note
Related Party Transaction [Line Items]
Period from public offering				5 days
Public offering proceeds threshold percentage				100%
Chief Executive Officer \| Duggan Promissory Notes
Related Party Transaction [Line Items]
Promissory note, prepayment triggering event, public offering proceeds threshold			$ 500,000
New note issuances \| promissory_note			2
Chief Executive Officer \| Duggan February Note
Related Party Transaction [Line Items]
Promissory note				$ 400,000
Interest rate	12%
Effective interest rate					8.90%
Chief Executive Officer \| Duggan February Note \| Prime rate
Related Party Transaction [Line Items]
Interest rate margin	3.50%
Chief Executive Officer \| Duggan September Note
Related Party Transaction [Line Items]
Promissory note				100,000
Effective interest rate					12.40%
Chief Executive Officer and President \| Zanganeh Note
Related Party Transaction [Line Items]
Promissory note				$ 20,000
Repayment of promissory notes		$ 20,000
Effective interest rate					8.90%
Related Party \| Promissory Notes
Related Party Transaction [Line Items]
Non-current promissory note payable to a related party					$ 100,000		100,000
Interest expense					3,121	8,327
Amortized imputed interest						$ 761
Future principal payments for 2024					0
Future principal payments for 2025					100,000
Related Party \| Promissory Notes, Accrued Interest
Related Party Transaction [Line Items]
Other non-current liabilities					$ 1,740
Accrued liabilities							$ 120

Stock-Based Compensation and _3

Stock-Based Compensation and Warrants - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 12, 2023	Mar. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding (in shares)		5,015,642	5,015,642
Warrants exercisable (in shares)		5,015,642	5,015,642
Weighted average exercise price of warrants outstanding (in dollars per share)		$ 1.57	$ 1.57
Weighted average exercise price of warrants exercisable (in dollars per share)		$ 1.57	$ 1.57
Time-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value, outstanding options		$ 113,727
Aggregate intrinsic value, exercisable options		3,146
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value, outstanding options		117,019
Performance-based stock options probable of vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost for unvested stock options		11,313
Performance-based stock options not-probable of vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost for unvested stock options		$ 44,816
Unvested stock options (in shares)		37,223,376
2020 Stock Incentive Plan \| Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase to number of shares of common stock issuable (in shares)	70,000,000

Stock-Based Compensation and _4

Stock-Based Compensation and Warrants - Stock Option Activity (Details)	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Time-based stock options
Number of Options
Beginning balance (in shares) \| shares	54,209,289
Granted (in shares) \| shares	1,503,876
Forfeited (in shares) \| shares	(780,500)
Exercised (in shares) \| shares	(80,810)
Ending balance (in shares) \| shares	54,851,855
Weighted average exercise price
Beginning balance (in dollars per share) \| $ / shares	$ 2.28
Granted (in dollars per share) \| $ / shares	3.49
Forfeited (in dollars per share) \| $ / shares	2.51
Exercised (in dollars per share) \| $ / shares	1.99
Ending balance (in dollars per share) \| $ / shares	$ 2.31
Stock option activity, additional disclosures
Stock options, exercisable (in shares) \| shares	6,002,166
Weighted average exercise price, exercisable (in dollars per share) \| $ / shares	$ 4.79
Performance-based stock options
Number of Options
Beginning balance (in shares) \| shares	46,654,220
Granted (in shares) \| shares	150,000
Forfeited (in shares) \| shares	(275,000)
Exercised (in shares) \| shares	0
Ending balance (in shares) \| shares	46,529,220
Weighted average exercise price
Beginning balance (in dollars per share) \| $ / shares	$ 1.62
Granted (in dollars per share) \| $ / shares	3.77
Forfeited (in dollars per share) \| $ / shares	1.76
Exercised (in dollars per share) \| $ / shares	0
Ending balance (in dollars per share) \| $ / shares	$ 1.63
Stock option activity, additional disclosures
Stock options, exercisable (in shares) \| shares	0
Weighted average exercise price, exercisable (in dollars per share) \| $ / shares	$ 0

Stock-Based Compensation and _5

Stock-Based Compensation and Warrants - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 9,507	$ 2,775
Time-based stock options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	8,115	2,671
Performance-based stock options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,321	48
Employee stock purchase plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	71	56
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	2,414	1,086
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 7,093	$ 1,689

Related Party Transactions (Det

Related Party Transactions (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	Oct. 13, 2023 USD ($) $ / shares shares	Mar. 01, 2023 USD ($) $ / shares shares	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 06, 2022 USD ($)	Jul. 29, 2022 ft²	Jul. 25, 2022 ft²
Related Party Transaction [Line Items]
Proceeds from offering			$ 0	$ 104,686
Issuance costs			0	539
Rights offering
Related Party Transaction [Line Items]
Offering price (in dollars per share) \| $ / shares		$ 1.05
Proceeds from offering		$ 500,000
Shares issued in transaction (in shares) \| shares		476,190,471
Issuance costs		$ 619
Issuance of common stock			0	395,314
Affiliated entity \| First Amendment to Sublease Agreement
Related Party Transaction [Line Items]
Area of premises subleased \| ft²							4,500
Sublease extension term							39 months
Payments to related party			195	189
Affiliated entity \| Second Amendment to Sublease Agreement
Related Party Transaction [Line Items]
Area of premises subleased \| ft²						1,277
Payments to related party			$ 55	$ 54
Chief Executive Officer \| Rights offering
Related Party Transaction [Line Items]
Issuance of common stock		$ 395,314
Chief Executive Officer \| Duggan February Note
Related Party Transaction [Line Items]
Promissory note					$ 400,000
Chief Operating Officer
Related Party Transaction [Line Items]
Proceeds from private placement	$ 5,000
Chief Operating Officer \| Private placement
Related Party Transaction [Line Items]
Offering price (in dollars per share) \| $ / shares	$ 1.68
Shares issued in transaction (in shares) \| shares	2,976,190

Commitment and Contingencies (D

Commitment and Contingencies (Details)	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Period for which the majority of contractual commitments are to be paid	1 year