0000950170-24-038059 | 10-K | XBRL Viewer

Warrants	12 Months Ended
Dec. 31, 2023
Warrants and Rights Note Disclosure [Abstract]
Warrants	10. Warrants The Company issued warrants exercisable for 1,500 shares of common stock on June 15, 2015 with an exercise price of $2.70 per share, which warrants expired at the end of their 7-year term on June 15, 2022. The Company issued another tranche of warrants exercisable for an aggregate of 882,071 shares of common stock with an exercise price of $9.38 per share when issued on December 27, 2017, which warrants expired at the end of their 5-year term on December 26, 2022. On November 16, 2022 the Company issued 9,188,406 warrants with an exercise price of $3.93 and a 5-year term and 1,531,440 Pre-Funded Warrants at a nominal exercise price of $0.0001 per share. These November 2022 warrants remain outstanding at December 31, 2023 and 2022. Each tranche of warrants was evaluated under ASC 480, Distinguishing Liabilities from Equity, and ASC 815, Derivatives and Hedging, and the Company determined that equity classification was appropriate. The Company determined equity classification for both warrants and pre-funded warrants as they do not embody an obligation for the Company to repurchase its shares and permit the holders to receive a fixed number of shares of common stock upon exercise. Per ASC 815-40-25, the Company accounts for the warrants and pre-funded warrants as equity, as the Company does not provide the holder a fixed or guaranteed return. The Company recorded cash received from 7,656,966 shares of common stock, 9,188,406 warrants to purchase shares of common stock and 1,531,440 Pre-Funded Warrants to additional paid in capital in the amount of $27,394,687, net of placement fees of $2,597,649 during the year ended December 31, 2022. The Company recorded placement fees and expenses related to the sale of shares of common stock, warrants to purchase shares of common stock and Pre-Funded Warrants as a debit to additional paid in capital in the consolidated balance sheet.

Warrants

12 Months Ended

Dec. 31, 2023

Warrants and Rights Note Disclosure [Abstract]

10. Warrants

The Company issued warrants exercisable for 1,500 shares of common stock on June 15, 2015 with an exercise price of $2.70 per share, which warrants expired at the end of their 7-year term on June 15, 2022. The Company issued another tranche of warrants exercisable for an aggregate of 882,071 shares of common stock with an exercise price of $9.38 per share when issued on December 27, 2017, which warrants expired at the end of their 5-year term on December 26, 2022.

On November 16, 2022 the Company issued 9,188,406 warrants with an exercise price of $3.93 and a 5-year term and 1,531,440 Pre-Funded Warrants at a nominal exercise price of $0.0001 per share. These November 2022 warrants remain outstanding at December 31, 2023 and 2022.

Each tranche of warrants was evaluated under ASC 480, Distinguishing Liabilities from Equity, and ASC 815, Derivatives and Hedging, and the Company determined that equity classification was appropriate. The Company determined equity classification for both warrants and pre-funded warrants as they do not embody an obligation for the Company to repurchase its shares and permit the holders to receive a fixed number of shares of common stock upon exercise. Per ASC 815-40-25, the Company accounts for the warrants and pre-funded warrants as equity, as the Company does not provide the holder a fixed or guaranteed return.

The Company recorded cash received from 7,656,966 shares of common stock, 9,188,406 warrants to purchase shares of common stock and 1,531,440 Pre-Funded Warrants to additional paid in capital in the amount of $27,394,687, net of placement fees of $2,597,649 during the year ended December 31, 2022. The Company recorded placement fees and expenses related to the sale of shares of common stock, warrants to purchase shares of common stock and Pre-Funded Warrants as a debit to additional paid in capital in the consolidated balance sheet.

Subsequent Events - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	Mar. 28, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
Issuance of common stock from public offerings, net of underwriter discounts, Shares		7,656,966
Agreement2 [Member] \| Transaction Expense [Member]
Subsequent Event [Line Items]
Proceeds from sale of common stock		$ 3.4
Issuance of common stock from public offerings, net of underwriter discounts, Shares		1,428,200
Agreement2 [Member] \| Transaction Expense [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from sale of common stock	$ 40.4
Issuance of common stock from public offerings, net of underwriter discounts, Shares	9,028,573

Loan with First Citizens Bank (formerly with Silicon Valley Bank) (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Maturities of Long-Term Debt [Table Text Block]


The following table presents the aggregate maturities of Long-term debt as of December 31, 2023 (in thousands):

Year
2024	$	4,000
2025		4,000
Total	$	8,000

The following table presents long-term and current portions of debt as of December 31, 2023 (in thousands):

Long-term debt	$	4,000
Accretion of final payment		239
Less: unamortized debt issuance costs		(37	)
Long-term debt, net	$	4,202
Current portion of long-term debt	$	4,000
Less: unamortized debt issuance costs		(37	)
Current portion of long-term debt, net	$	3,963

CONSOLIDATED BALANCE SHEETS - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 48,514,000	$ 51,614,000
Marketable securities	0	24,675,000
Accounts receivable	1,698,000	57,000
Prepaid expenses and other current assets	1,242,000	841,000
Total current assets	51,454,000	77,187,000
Property and equipment, net	795,000	1,499,000
Operating lease right-of-use assets	6,323,000	9,203,000
Deposits	2,690,000	3,116,000
Restricted cash	151,000	150,000
Other long term assets	117,000	128,000
Total assets	61,530,000	91,283,000
Current liabilities:
Accounts payable	3,501,000	2,731,000
Accrued expenses	4,137,000	3,554,000
Research and development contract liability, current portion	2,112,000	0
Operating lease liabilities, current portion	3,368,000	3,300,000
Current portion of long-term debt, net	3,963,000	1,963,000
Total current liabilities	17,081,000	11,548,000
Operating lease liabilities, net of current portion	3,162,000	6,018,000
Long-term debt, net	4,202,000	8,035,000
Total liabilities	24,445,000	25,601,000
Commitments and contingencies (NOTE 15)
Stockholders’ equity:
Preferred stock, $0.001 par value, authorized – 10,000,000 shares; issued and outstanding – none	0	0
Common stock, $0.001 par value; authorized - 100,000,000 shares; issued and outstanding - 43,042,548 shares and 43,042,548 shares at December 31, 2023 and 2022, respectively	47,000	43,000
Additional paid in capital	338,228,000	316,192,000
Accumulated other comprehensive income	0	(96,000)
Accumulated deficit	(301,190,000)	(250,457,000)
Total stockholders’ equity	37,085,000	65,682,000
Total liabilities and stockholders’ equity	$ 61,530,000	$ 91,283,000

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (50,733,000)	$ (53,010,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	556,000	922,000
Stock-based compensation	8,180,000	9,496,000
Decrease in the carrying amount of right-of-use assets	2,880,000	884,000
Amortization of premium/discount on purchased securities	(234,000)	(321,000)
Gain on right-of-use asset modification	0	(277,000)
Loss on disposal of fixed asset	157,000	4,000
Amortization of debt issuance costs	37,000	31,000
Accretion of final payment of term loan	130,000	109,000
Changes in operating assets and liabilities:
Account receivable	(1,641,000)	3,085,000
Prepaid expenses and other current assets	(401,000)	34,000
Deposits	426,000	(395,000)
Accounts payable	770,000	83,000
Accrued expenses	588,000	(1,071,000)
Research and development contract liability, current portion	2,112,000	(645,000)
Operating lease liability	(2,788,000)	(735,000)
Net cash used in operating activities	(39,961,000)	(41,806,000)
Cash flows from investing activities:
Purchases of property and equipment	0	(171,000)
Cash received from sale of fixed asset	2,000	6,000
Redemption of marketable securities	25,000,000	5,000,000
Purchases of marketable securities	0	(29,445,000)
Net cash provided by investing activities	25,002,000	(24,610,000)
Cash flows from financing activities:
Proceeds from ATM offering, net of sales agent commission and fees	13,387,000	16,598,000
Proceeds from common stock issuance, net of transaction costs	0	22,702,000
Proceeds from pre-funded warrant issuance, net of transaction costs	0	4,700,000
Proceeds from borrowing under term loan	0	10,000,000
Payment of term loan	(2,000,000)	0
Proceeds from the exercise of stock options	473,000	0
Payment of debt issuance costs	0	(141,000)
Restricted stock awards withheld at vesting to cover taxes	0	(200,000)
Net cash provided by financing activities	11,860,000	53,659,000
Net decrease in cash, cash equivalents, and restricted cash	(3,099,000)	(12,757,000)
Cash, cash equivalents, and restricted cash at beginning of year	51,764,000	64,521,000
Cash, cash equivalents, and restricted cash at end of year	48,665,000	51,764,000
Supplemental disclosures of cash flow information:
Purchases of property and equipment in accounts payable or accrued expenses	0	57,000
Cash paid for interest	1,003,000	570,000
Right-of-use asset and lease liability (new lease)	0	10,733,000
Operating lease modification	$ 0	$ 8,083,000

Loan with First Citizens Bank (formerly with Silicon Valley Bank) - Summary of Future Principal Debt Payments on Term Loan Agreement (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instruments [Abstract]
2024	$ 4,000
2025	4,000
Total maturities	8,000
Long-term debt	4,000
Accretion of final payment	239
Less: unamortized debt issuance costs	(37)
Long-term debt, net	4,202	$ 8,035
Current portion of long-term debt	4,000
Less: unamortized debt issuance costs	(37)
Current portion of long-term debt, net	$ 3,963	$ 1,963

Collaboration Revenue

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Collaboration Revenue

11. Collaboration Revenue

The Company recognizes collaboration revenue under certain of the Company’s license or collaboration agreements that are within the scope of ASC 606. The Company’s contracts with customers typically include promises related to licenses to intellectual property and research and development services. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and if, over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. The Company’s contracts may include options to acquire additional goods and/or services.

The terms of the Company’s arrangements with customers typically include the payment of one or more of the following: (i) non-refundable, up-front payment, and pass through costs related to research activities, (ii) development, regulatory and commercial milestone payments, (iii) future options and (iv) royalties on net sales of licensed products. Accordingly, the transaction price is generally comprised of a fixed fee due at contract inception and variable consideration in the form of pass through costs and milestone payments due upon the achievement of specified events and tiered royalties earned when customers recognize net sales of licensed products. The Company measures the transaction price based on the amount of consideration to which it expects to be entitled in exchange for transferring the promised goods and/or services to the customer. The Company utilizes the “expected value method” method to estimate the amount of variable consideration, to predict the amount of consideration to which it will be entitled for its one open contract. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Milestone payments that are not within the control of the Company or the licensee, such as those dependent upon receipt of regulatory approval, are not considered to be probable of achievement until the triggering event occurs. At the end of each reporting period, the Company reevaluates the probability of achievement of each milestone and any related constraint, and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment.

For arrangements that include sales-based royalties, including milestone payments based upon the achievement of a certain level of product sales, the Company recognizes revenue upon the later of: (i) when the related sales occur or (ii) when the performance obligation to which some or all of the payment has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any development, regulatory or commercial milestones or royalty revenue resulting from any of its collaboration arrangements. Consideration that would be received for optional goods and/or services is excluded from the transaction price at contract inception.

The Company allocates the transaction price to each performance obligation identified in the contract on a relative standalone selling price basis, when applicable. However, certain components of variable consideration are allocated specifically to one or more particular performance obligations in a contact to the extent both of the following criteria are met: (i) the terms of the payment relate specifically to the efforts to satisfy the performance obligation or transfer the distinct good or service and (ii) allocating the variable amount of consideration entirely to the performance obligation or the distinct good or service is consistent with the allocation objective of the standard whereby the amount allocated depicts the amount of consideration to which the entity expects to be entitled in exchange for transferring the promised goods or services. The Company develops assumptions that require judgment to determine the standalone selling price for each performance obligation identified in each contract. The key assumptions utilized in determining the standalone selling price for each performance obligation may include forecasted revenues, development timelines, estimated research and development costs, discount rates, likelihood of exercise and probabilities of technical and regulatory success.

Revenue is recognized based on the amount of the transaction price that is allocated to each respective performance obligation when or as the performance obligation is satisfied by transferring a promised good and/or service to the customer. For performance obligations that are satisfied over time, the Company recognizes revenue by measuring the progress toward complete satisfaction of the performance obligation using a single method of measuring progress which depicts the performance in transferring control of the associated goods and/or services to the customer. The Company uses input methods to measure progress toward the complete satisfaction of performance obligations satisfied over time. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. The Company measures progress toward satisfaction of the performance obligation over time as effort is expended.

Collaboration Agreement with LG Chem

On November 6, 2018, the Company entered into a collaboration agreement (the “LG Chem Collaboration Agreement”) with LG Chem Ltd. (“LG Chem”) related to the development of the Company’s Immuno-STATs focused in the field of

oncology. Pursuant to the LG Chem Collaboration Agreement, the Company granted LG Chem an exclusive license to develop, manufacture and commercialize the Company’s lead product, CUE-101, as well as Immuno-STATs that target T cells against two additional cancer antigens, in certain Asian countries (collectively, the “LG Chem Territory”). On April 30, 2021, LG Chem’s option pursuant to the Global License and Collaboration Agreement entered into between the Company and LG Chem on December 18, 2019 and as amended on November 5, 2020 (the "Global License and Collaboration Agreement"), expired, and accordingly the Company no longer has any material obligations under the Global License and Collaboration Agreement. In June 2021, after ongoing discussions regarding the selection of the second of the two additional cancer antigens, LG Chem and the Company agreed to let the selection period expire without a second antigen being selected. The Company retains rights to develop and commercialize all assets included in the LG Chem Collaboration Agreement in the United States and in global markets outside of the LG Chem Territory. In exchange for the licenses and other rights granted to LG Chem under the LG Chem Collaboration Agreement, LG Chem made a $5.0 million equity investment in common stock of the Company and a $5.0 million nonrefundable up-front cash payment. The Company is also eligible to receive up to an additional $400.0 million in research, development, regulatory and sales milestones. In addition, the LG Chem Collaboration Agreement also provides that LG Chem will pay the Company tiered single-digit percentage royalties on net sales of commercialized drug product candidates in the LG Chem Territory.

On May 16, 2019, LG Chem paid the Company a $2.5 million milestone payment for the U.S. Food and Drug Administration’s (“FDA”) acceptance of the investigational new drug application (“IND”) for the Company’s lead drug product candidate, CUE-101, pursuant to the LG Chem Collaboration Agreement. The $2.5 million milestone payment was recorded as a contract liability upon receipt of payment as it requires deferral of revenue recognition to a future period until the Company performs its obligations under the arrangement. Of the $2.5 million milestone payment, approximately $412,500 was recognized as tax withholding, shown as income tax expense on the consolidated statement of operations and other comprehensive loss.

On December 7, 2020, the Company earned a $1.25 million milestone payment on the selection of a pre-clinical candidate pursuant to the LG Chem Collaboration Agreement. The $1.25 million milestone payment was recorded as a contract liability upon receipt. Revenue related to this milestone payment was recognized by the Company pursuant to the Company’s revenue recognition policy in relation to the performance of its obligations related to the development of this pre-clinical candidate. Of the $1.25 million milestone payment, approximately $206,250 was withheld as payment of foreign tax withholding and shown as income tax expense on the consolidated statement of operations and other comprehensive loss.

On November 23, 2021, the Company earned a $3 million milestone payment for the selection of a clinical product candidate in partnership with LG Chem. The $3 million milestone payment was recorded as a contract liability upon receipt. Revenue related to this milestone payment was recognized by the Company pursuant to the Company’s revenue recognition policy in relation to the performance of its obligations related to the development of this preclinical candidate. Of the $3 million milestone payment, approximately $495,000 was withheld as payment of foreign tax withholding and shown as income tax expense on the consolidated statements of operations and comprehensive loss. Cash was collected in relation to this milestone payment in February 2022.

Aside from the $6.75 million in milestone payments earned to date, the Company does not believe that any variable consideration should be included in the transaction price as of December 31, 2023. Such assessment considered the application of the constraint to ensure that estimates of variable consideration would be included in the transaction price only to the extent the Company had a high degree of confidence that revenue would not be reversed in a subsequent reporting period. The Company will re-evaluate the transaction price, including the estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as other changes in circumstances occur. For the years ended December 31, 2023 and 2022, the Company recognized revenue of approximately $324,000 and approximately $1,245,000, respectively, related to the LG Chem Collaboration Agreement. The Company did not record short or long-term research and development liabilities on its balance sheet dated December 31, 2023 and December 31, 2022, as the performance obligation was met and completed. Research and development cost sharing provisions under the agreement expired on March 31, 2022, thereafter the Company recognized revenue on intellectual patent filing passthrough costs in the LG Chem territory.

Collaboration and Option Agreement with Ono

On February 22, 2023, the Company entered into a strategic collaboration agreement (the "Ono Collaboration and Option Agreement") with Ono Pharmaceutical Co., Ltd. ("Ono") to further develop CUE-401 and provide dedicated resources and capabilities to help advance CUE-401 toward the clinic. Under the terms of the Ono Collaboration and Option Agreement, Ono paid the Company an upfront payment and agreed to fully fund all research activities related to CUE-401 through a specified option period. During this option period, the Company will be responsible for the research and development of

CUE-401. Upon Ono’s exercise of its option to license CUE-401, the Company will receive an option exercise payment and be eligible for development and commercial milestone payments up to an aggregate of approximately $220 million, as well as tiered royalties on sales. Upon any such exercise, Ono will receive worldwide rights to develop and commercialize CUE-401, with the Company retaining a 50% co-development and co-commercialization right in the United States. The Company’s decision to elect the co-development and co-commercialization option may be made within 30 days of Ono’s option exercise to license CUE-401. The amount paid by Ono to the Company for the option exercise and future milestone payments will vary based upon the Company’s decision to exercise the co-development and co-commercialization option.

Under the terms of the Ono Collaboration and Option Agreement, the Company will perform research activities related to CUE-401 through a specified option period of 24 months (the “Research Term”). During this Research Term, the Company will be responsible for the execution of scientific investigation, nonclinical, preclinical, and clinical drug research and development activities designed to progress CUE-401 toward a potential IND and regulatory approval (such activities, collectively referred to as “R&D”). Ono is responsible for the funding of R&D activities performed by the Company. Per the agreement, as consideration for the R&D activities performed by the Company, Ono (i) made a one-time, non-refundable, non-creditable upfront payment of $3.0 million to the Company and (ii) will reimburse the Company for all costs incurred in conducting research, including (a) pass through costs from third party contractors and (b) full time employee salaries capped at $2.1 million in the first 18 months of the Research Term. The term of the Ono Collaboration and Option Agreement extends until the expiration of the Research Term which cannot exceed a 24-month period. The Company has forecasted that it will be able to complete the R&D activities in the first 18 months of the Research Term based on the initial research and development plans it has established. The Company received the $3.0 million upfront payment in March 2023.

Aside from the $3.0 million upfront payment and funding related to pass through costs, the Company does not believe that any variable consideration should be included in the transaction price as of December 31, 2023. Such assessment considered the application of the constraint to ensure that estimates of variable consideration would be included in the transaction price only to the extent the Company had a high degree of confidence that revenue would not be reversed in a subsequent reporting period. The Company will re-evaluate the transaction price, including the estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as other changes in circumstances occur. For the years ended December 31, 2023 and 2022, the Company recognized revenue of approximately $5,166,000 and $0, respectively, related to the Ono Collaboration and Option Agreement. The Company recorded short-term research and development liabilities on its balance sheet dated December 31, 2023, of approximately $2,112,000. The Company did not recognize short or long-term research and development liabilities on its balance sheet as of December 31, 2022, as the agreement was executed in February 2023.

Capitalization of Contract Costs

The Company considered the capitalization of contract costs under the guidance in ASC 340-40, Other Assets and Deferred Costs: Contracts with Customers. As it related to the LG Chem Collaboration Agreement, the Company capitalized license expenses of approximately $908,000 as of December 31, 2022, paid to Einstein pursuant to the Einstein License Agreement which requires the Company to pay a percentage of sublicenses related to the Company’s patent rights for components of its core technology that is licensed from Einstein. This amount is comprised of approximately $438,000 of capitalized license expenses related to the up-front payment received from LG Chem in December 2018, approximately $313,000 in capitalized license expenses related to the milestone payment received in June 2019, and approximately $157,000 in capitalized license expenses related to the milestone payment received in December 2020, net of accumulated amortization of approximately $908,000. As of December 31, 2023 and 2022, no capitalized license expenses net of accumulated amortization were included in prepaid expenses and other short-term assets related to the LG Chem Collaboration Agreement. The Company has not capitalized license expenses related to the Ono Collaboration and Option Agreement, as CUE-401 does not contain components of the core technology licensed from Einstein.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Lease - Schedule of Other Information of Operating Leases (Details)	Dec. 31, 2023	Dec. 31, 2022
Cash Paid For Amounts Included In Measurement Of Lease Liabilities [Abstract]
Weighted average remaining lease term	2 years 1 month 28 days	3 years 1 month 9 days
Weighted average discount rate	6.25%	6.41%

Commitments and Contingencies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2015 SupportingTechnology
Commitments And Contingencies [Line Items]
Type of Cost, Good or Service [Extensible List]	us-gaap:LicenseMember
Einstein License
Commitments And Contingencies [Line Items]
Number of supporting technologies \| SupportingTechnology			2
Costs incurred	$ 7,000	$ 0
Type of Cost, Good or Service [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember
Albert Einstein College Of Medicine \| Einstein License And Service Agreement
Commitments And Contingencies [Line Items]
Milestone payments for each product, process or service	$ 1,850
Milestone payments for each new indication of licensed product	1,850
Aggregate amount of additional milestone payments	$ 5,750

Organization and Basis of Presentation

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Basis of Presentation

1. Organization and Basis of Presentation

Cue Biopharma, Inc. (the "Company") is a clinical-stage biopharmaceutical company engineering a novel class of injectable therapeutics to selectively engage and modulate targeted, disease relevant T cells directly within the patient’s body. The Company's vision is to translate nature's signals, or "cues", into protein therapeutics by generating a new class of T cell engagers for selective modulation of disease specific T cells. The Company’s corporate office and research facilities are located in Boston, Massachusetts.

The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. The Company is in the development stage and has incurred recurring losses and negative cash flows from operations since inception. As of December 31, 2023, the Company had cash and cash equivalents of approximately $48.5 million. Management believes that current cash and cash equivalents on hand at December 31, 2023 are sufficient to fund operations into the first quarter of 2025; however, the future viability of the Company is dependent on its ability to raise additional capital to finance its operations and to fund research and development costs in order to seek approval for commercialization of its drug product candidates. The Company is exploring raising additional capital through a combination of equity offerings, collaborations, and other strategic alliances, and, depending on the availability and level of additional financings, and cash expenditure reduction, there is no guarantee that we will be successful in these mitigation efforts. The Company’s failure to raise capital as and when needed would have a negative impact on its financial condition and its ability to pursue its business strategies as this capital is necessary for the Company to perform the research and development activities required to develop and commercialize the Company’s drug product candidates in order to generate future revenue streams. Therefore, management has determined that the Company’s accumulated deficit, history of losses, negative cash flows from operations and future expected losses raise substantial doubt about the Company’s ability to continue as a going concern within one year of the issuance date of these financial statements.

Einstein License and Service Agreement - Additional Information (Details)			12 Months Ended
	Dec. 27, 2017 shares	Jan. 14, 2015	Dec. 31, 2023 USD ($) SupportingTechnology shares	Dec. 31, 2022 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Shares of common stock \| shares			7,656,966
Type of Cost, Good or Service [Extensible List]			us-gaap:LicenseMember
Prepaid expenses and other current assets			$ 1,242,000	$ 841,000
Other long term assets			$ 117,000	$ 128,000
Einstein License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement entered date		Jan. 14, 2015
Number of supporting technology \| SupportingTechnology			2
Nonrefundable milestone payments			$ 1,233,000
Shares of common stock \| shares	671,572

Stock-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Details) - Restricted Stock Units	Aug. 21, 2020 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Nonvested balance as of December 31, 2021	100,000
Number of Shares, Nonvested balance at December 31, 2022	20,000

- Definition

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

+ References

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+ Details

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of Future Minimum Lease Payments for Operating Lease

Future minimum lease payments under these leases at December 31, 2023 are as follows:


Year	(in thousands)
2024		3,368
2025		2,799
2026		818
Total lease payments		6,985
Less: present value discount		(455	)
Present value of lease payments	$	6,530

Lease, Cost [Table Text Block]

Other information pertaining to the Company’s operating leases for the twelve months ended December 31, 2023 is summarized in the table below.

The weighted average remaining lease term and discount rate related to the Company's leases were as follows:


	December 31,
	2023			2022
Weighted average remaining lease term (years)		2.16			3.11
Weighted average discount rate		6.25	%		6.41	%

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Presentation

The accompanying consolidated financial statements for the years ended December 31, 2023 and 2022, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and Generally Accepted Accounting Principles in the United States (“U.S. GAAP”) for financial information, which prescribes elimination of all significant intercompany accounts and transactions in the accounts of the Company and its wholly owned subsidiary, Cue Biopharma Securities Corp., which was incorporated in the Commonwealth of Massachusetts in December 2018. In the opinion of management, these financial statements reflect all adjustments which are necessary for a fair statement of the Company’s financial position and results of its operations, as of and for the periods presented.

Public Offerings

In October 2021, the Company entered into an open market sale agreement (the “October 2021 ATM Agreement”) with Jefferies LLC ("Jefferies"), as agent, to sell shares of the Company’s common stock for aggregate gross proceeds of up to $80 million, from time to time, through an at-the-market equity offering program. The October 2021 ATM Agreement will terminate upon the earliest of (a) the sale of $80 million of shares of the Company’s common stock pursuant to the October 2021 ATM Agreement or (b) the termination of the October 2021 ATM Agreement by the Company or Jefferies. During the year ended December 31, 2023, the Company sold 4,006,966 shares of common stock under the October 2021 ATM Agreement for proceeds of approximately $13.4 million, net of commission paid, but excluding transaction expense. As of December 31, 2023, the Company sold an aggregate of 7,600,373 shares of common stock under the October 2021 ATM Agreement for proceeds of approximately $37.0 million, net of commission paid, but excluding transaction expenses, since its inception.

Issuance of Securities through a Private Placement

On November 14, 2022, the Company entered into securities purchase agreements with accredited investors pursuant to which, on November 16, 2022, the Company issued and sold to such investors in a private placement an aggregate of

7,656,966 shares of common stock and, in lieu of shares of common stock to certain investors, pre-funded warrants ("Pre-Funded Warrants") to purchase an aggregate of 1,531,440 shares of common stock, and, in each case, accompanying warrants ("Warrants") to purchase an aggregate of up to 9,188,406 additional shares of common stock (or Pre-Funded Warrants in lieu thereof) at a price of $3.265 per share and accompanying Warrant (or $3.2649 per Pre-Funded Warrant and accompanying Warrant), (such financing, the "PIPE Financing"). The exercise price of the Warrants is $3.93 per share, or if exercised for a Pre-Funded Warrant in lieu thereof, $3.9299 per Pre-Funded Warrant. The Warrants are exercisable at any time after they are issued and ending on the fifth anniversary of the closing. The Pre-Funded Warrants are exercisable at any time after they are issued and will not expire. The Company received aggregate gross proceeds from the PIPE Financing of approximately $30 million, before deducting placement agent fees and offering expenses of approximately $2.6 million. Piper Sandler & Co. acted as lead placement agent and Public Ventures LLC acted as co-placement agent for the PIPE Financing.

The Warrants are classified as a component of permanent equity because they are freestanding financial instruments that are legally detachable and separately exercisable from the shares of common stock with which they were issued, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, and permit the holders to receive a fixed number of shares of common stock upon exercise. In addition, the Warrants do not provide any guarantee of value or return at December 31, 2023, the weighted average exercise price is $3.93 and the weighted average contractual life is five years. The Pre-Funded Warrants do not have an expiration date.

The Pre-Funded Warrants met the permanent equity criteria classification. The Pre-Funded Warrants are classified as a component of permanent equity because they are freestanding financial instruments that are legally detachable and separately exercisable from the shares of common stock with which they were issued, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, and permit the holders to receive a fixed number of shares of common stock upon exercise. In addition, the Pre-Funded Warrants do not provide any guarantee of value or return.

Consolidation

The accompanying consolidated financial statements include the Company and its wholly owned subsidiary, Cue Biopharma Securities Corp. The Company has eliminated all intercompany transactions.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates include estimates related to collaboration revenue, the accounting for potential liabilities and accrued expenses, the assumptions utilized in valuing stock-based compensation issued for services, the realization of deferred tax assets, and the useful life with respect to long-lived assets and intangibles. Actual results could differ from those estimates.

Cash Concentrations

The Company maintains its cash balances with financial institutions in federally insured accounts and may periodically have cash balances in excess of insurance limits. The Company maintains its accounts with financial institutions with a high credit rating. The Company has not experienced any losses to date from our deposits with these financial institutions and believes that it is not exposed to any significant credit risk on cash.

Cash and Cash Equivalents

The Company considers all highly liquid investments with a maturity of three months or less at the date of purchase to be cash equivalents. The Company currently invests available cash in money market funds.

Marketable Securities

Marketable securities consist of investments with original maturities greater than ninety days and less than one year from the balance sheet date. The Company classifies all of its investments as available-for-sale securities. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are recognized and determined on a specific identification basis and are included in other comprehensive loss. Realized gains and losses are determined on a specific identification basis and are included in other income on the consolidated statement of operations and other comprehensive loss. Amortization and accretion of discounts and premiums is recorded in interest income. At December 31, 2023, the Company has invested available cash in money market funds, and at December 31, 2022 the Company invested available cash in U.S. Treasury securities.

Restricted Cash

The Company had approximately $150,000 in restricted cash deposited with separate commercial banks to collateralize company credit cards as of December 31, 2023 and 2022.

Property and Equipment

Property and equipment is recorded at cost. Major improvements are capitalized, while maintenance and repairs are charged to expense as incurred. Gains and losses from dispositions of property and equipment are included in income and expense when realized. Amortization of leasehold improvements is provided using the straight-line method over the shorter of the lease term or the useful life of the underlying assets. Depreciation of property and equipment is provided using the straight-line method over the following estimated useful lives:


Laboratory equipment		5 years
Computer equipment		3 years
Furniture and fixtures		3-8 years

The Company recognizes depreciation and amortization expense in general and administrative expenses and in research and development expenses in the Company’s consolidated statements of operations and comprehensive loss, depending on how each category of property and equipment is utilized in the Company’s business activities.

Trademark

Trademark consists of the Company’s right, title and interest to the CUE BIOLOGICS Mark, and any derivative mark incorporating CUE, throughout the world, together with all associated goodwill and common law rights appurtenant thereto, including, but not limited to, any right, title and interest in any corporate name, company name, business, name, trade name, dba, domain name, or other source identifier incorporating CUE.

The Company has classified the trademark as a component of other long-term assets, having a useful life of 15 years. The Company evaluates the status of this intangible asset for amortization and impairment at each quarter end and year end reporting date. The Company recorded $11,000 in amortization related to the trademark at December 31, 2023 and 2022.

Debt Issuance Costs

Revenue Recognition

The Company recognizes collaboration revenue under certain of the Company’s license and collaboration agreements that are within the scope of Accounting Standards Codification (“ASC”), Topic 606, Revenue from Contracts with Customers (“ASC 606”). The Company’s contracts with customers typically include promises related to licenses to intellectual property and research and development services. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. Accordingly, the transaction price is generally comprised of a fixed fee due at contract inception and variable consideration in the form of milestone payments due upon the achievement of specified events and tiered royalties earned when customers recognize net sales of licensed products. The Company measures the transaction price based on the amount of consideration to which it expects to be entitled in exchange for transferring the promised goods and/or services to the customer. The Company utilizes the “expected value method” method to estimate the amount of variable consideration, to predict the amount of consideration to which it will be entitled for its one open contract. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. At the inception of each arrangement that includes development and regulatory milestone payments, the Company evaluates whether

the associated event is considered probable of achievement and estimates the amount to be included in the transaction price using the expected value method.

Research and Development Expenses

Research and development expenses consist primarily of compensation costs, fees paid to consultants, outside service providers and organizations (including research institutes at universities), facility costs, and development and clinical trial costs with respect to the Company’s drug product candidates.

Research and development expenses incurred under contracts are expensed ratably over the life of the underlying contracts, unless the achievement of milestones, the completion of contracted work, or other information indicates that a different pattern of performance is more appropriate. Other research and development expenses are charged to operations as incurred.

Nonrefundable advance payments are recognized as an expense as the related services are performed. The Company evaluates whether it expects the services to be rendered at each quarter end and year end reporting date. If the Company does not expect the services to be rendered, the advance payment is charged to expense. Nonrefundable advance payments for research and development services are included in prepaid and other current assets on the balance sheet. To the extent that a nonrefundable advance payment is for contracted services to be performed within 12 months from the reporting date, such advance is included in current assets; otherwise, such advance is included in non-current assets.

The Company evaluates the status of its research and development agreements and contracts, and the carrying amount of the related assets and liabilities, at each quarter end and year end reporting date, and adjusts the carrying amounts and their classification on the balance sheet as appropriate.

Patent Expenses

The Company is the exclusive worldwide licensee of, and has patent applications pending for, numerous domestic and foreign patents. Due to the significant uncertainty associated with the successful development of one or more commercially viable drug product candidates based on the Company’s research efforts and any related patent applications, all patent costs, including patent-related legal fees, filing fees and other costs are charged to general and administrative expense as incurred. For the years ended December 31, 2023 and 2022, patent expenses were approximately $2,473,000 and $2,142,000, respectively.

Licensing Fees and Costs

Licensing fees and costs consist primarily of costs relating to the acquisition of the Company’s license agreement (the “Einstein License Agreement”) with the Albert Einstein College of Medicine (“Einstein”), including related royalties, maintenance fees, milestone payments and product development costs. Licensing fees and costs are charged to research and development expense as incurred.

Long-Lived Assets

The Company reviews long-lived assets, consisting of property and equipment, for impairment when events or changes in circumstances indicate the carrying value of these assets may exceed their current fair values. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset exceeds the fair value of the assets. Assets to be disposed of are separately presented in the balance sheet and reported at the lower of the carrying amount or fair value less costs to sell and are no longer depreciated. The Company has not historically recorded any impairment to its long-lived assets. In the future, if events or market conditions affect the estimated fair value to the extent that a long-lived asset is impaired, the Company will adjust the carrying value of these long-lived assets in the period in which the impairment occurs. During the year ended December 31, 2023, the Company sold furniture and fixtures and lab equipment with an acquisition cost of $41,000 and collected cash of $2,000 and disposed of gross assets of approximately $1,289,000. The Company recorded a loss on the sale and disposal of fixed assets of $157,000, which is presented in other income on the consolidated statement of operations and other comprehensive loss. During the year ended December 31, 2022, the Company sold furniture and fixtures and lab equipment with an acquisition cost of $43,000 and collected cash of $6,200. The Company recorded a loss on the sale of fixed assets of $4,000, which is presented in other income on the consolidated statement of operations and other comprehensive loss.

Leases

The Company accounts for leases under ASC 842 Leases, which requires a lessee to record a right-of-use asset and a corresponding lease liability for most lease arrangements on the balance sheet. Under the standard, disclosure of key information about leasing arrangements to assist users of the financial statements with assessing the amount, timing and uncertainty of cash flows arising from leases are required.

Stock-Based Compensation

The Company periodically issues stock-based awards to officers, directors, employees, Scientific and Clinical Advisory Board members and consultants for services rendered. Such issuances vest and expire according to terms established at the issuance date.

Stock-based payments to officers, directors, employees, Scientific and Clinical Advisory Board members and consultants, including grants of employee stock options, are recognized in the financial statements based on their grant date fair values. Stock option grants, which are generally time-vested, are measured at the grant date fair value and charged to operations on a straight-line basis over the service period, which generally approximates the vesting term. The Company also grants performance-based awards periodically to officers of the Company. The Company recognizes compensation costs related to performance awards over the requisite service period if and when the Company concludes that it is probable that the performance condition will be achieved.

The fair value of stock options and restricted stock units is determined utilizing the Black-Scholes option-pricing model, which is affected by several variables, including the risk-free interest rate, the expected dividend yield, the life of the equity award, the exercise price of the stock option as compared to the fair value of the common stock on the grant date, and the estimated volatility of the common stock over the term of the equity award.

The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant. Until the Company has established a trading history for its common stock that approximates the expected term of the options, estimated volatility is based on the average historical volatility of comparable public companies in a similar industry. The expected dividend yield is based on the current yield at the grant date; the Company has never declared or paid dividends and has no plans to do so for the foreseeable future. As permitted by Staff Accounting Bulletin No. 107, due to the Company’s limited trading history and option activity, management utilizes the simplified method to estimate the expected term of options at the date of grant. The exercise price is determined based on the fair value of our common stock at the date of grant. The Company accounts for forfeitures as they occur.

The Company recognizes the fair value of stock-based compensation in general and administrative expenses and in research and development expenses in the Company’s consolidated statements of operations and comprehensive loss, depending on the type of services provided by the recipient of the equity award.

Income Taxes

The Company accounts for income taxes under an asset and liability approach for financial accounting and reporting for income taxes. Accordingly, the Company recognizes deferred tax assets and liabilities for the expected impact of differences between the financial statements and the tax basis of assets and liabilities.

The Company accounts for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by U.S. GAAP. The tax effects of a position are recognized only if it is “more-likely-than-not” to be sustained by the taxing authority as of the reporting date. If the tax position is not considered “more-likely-than-not” to be sustained, then no benefits of the position are recognized.

The Company records a valuation allowance to reduce its deferred tax assets to the amount that is more likely than not to be realized. In the event the Company was to determine that it would be able to realize its deferred tax assets in the future in excess of its recorded amount, an adjustment to the deferred tax assets would be credited to operations in the period such determination was made. Likewise, should the Company determine that it would not be able to realize all or part of its deferred tax assets in the future, an adjustment to the deferred tax assets would be charged to operations in the period such determination was made.

The Company is subject to U.S. federal and Massachusetts state income taxes. As the Company’s net operating losses have yet to be utilized, all previous tax years remain open to examination by federal and state taxing authorities in which the Company currently operates.

For the years ended December 31, 2023 and 2022, there is no provision for income taxes in the U.S. because the Company has historically incurred net operating losses and maintains a full valuation allowance against its net deferred assets. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in valuation allowance.

The Company recognizes interest accrued relative to unrecognized tax benefits in interest expense and penalties in operating expense. During the years ended December 31, 2023 and 2022, the Company did not recognize any income tax related interest and penalties. The Company did not have any accruals for income tax related interest and penalties at December 31, 2023 and 2022.

Comprehensive Income (Loss)

Components of comprehensive income or loss, including net income or loss, are reported in the financial statements in the period in which they are recognized. Other comprehensive income or loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources. Net income (loss) and other comprehensive income (loss) are reported net of any related tax effect to arrive at comprehensive income (loss). Comprehensive income (loss) includes net income (loss) as well as changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) in periods presented was unrealized gain or loss on available-for-sale securities.

Earnings (Loss) Per Share

The Company’s computation of earnings (loss) per share (“EPS”) for the respective periods includes basic and diluted EPS. Basic EPS is measured as the income (loss) attributable to common stockholders divided by the weighted average number of common shares outstanding for the period. Diluted EPS is similar to basic EPS but presents the dilutive effect on a per share basis of potential common shares that would result from the exercise of outstanding stock options and warrants as if they had been exercised at the beginning of the periods presented, or issuance date, if later. Potential common shares that have an anti-dilutive effect (i.e., those that increase income per share or decrease loss per share) are excluded from the calculation of diluted EPS. Basic and diluted loss per common share is the same for all periods presented because all outstanding stock options and warrants are anti-dilutive.

Per ASC 260-10-45-13, shares issuable for little to no consideration should be included in the number of outstanding shares used for basic EPS. The Financial Accounting Standards Board (“FASB”) proposed that warrants or options exercisable for little to no cost (sometimes referred to as “penny warrants”) be included in the denominator of basic EPS (and therefore diluted EPS) once there were no further vesting conditions or contingencies associated with them. The Company included 1,531,440 pre-funded warrants in the denominator of basic EPS at December 31, 2023.

At December 31, 2023 and 2022, the Company excluded the outstanding securities summarized below, which entitled the holders thereof to acquire shares of common stock, from its calculation of EPS, as their effect would have been anti-dilutive.


	December 31,
	2023		2022
Common stock warrants		10,719,846		10,719,846
Common stock options		10,800,379		6,740,122
Total		21,520,225		17,459,968

Fair Value of Financial Instruments

The authoritative guidance with respect to fair value established a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels and requires that assets and liabilities carried at fair value be classified and disclosed in one of three categories, as presented below.

Level 1. Observable inputs such as quoted prices in active markets for an identical asset or liability that the Company has the ability to access as of the measurement date. Financial assets and liabilities utilizing Level 1 inputs include active exchange-traded securities and exchange-based derivatives.

Level 2. Inputs, other than quoted prices included within Level 1, which are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. Financial assets and liabilities utilizing Level 2 inputs include fixed income securities, non-exchange-based derivatives, mutual funds, and fair-value hedges.

Level 3. Unobservable inputs in which there is little or no market data for the asset or liability which requires the reporting entity to develop its own assumptions. Financial assets and liabilities utilizing Level 3 inputs include infrequently traded non-exchange-based derivatives and commingled investment funds and are measured using present value pricing models.

The Company determines the level in the fair value hierarchy within which each fair value measurement falls in its entirety, based on the lowest level input that is significant to the fair value measurement in its entirety. In determining the appropriate levels, the Company performs an analysis of the assets and liabilities at each reporting period end.

The Company had approximately $39,148,000 in cash equivalents and $0 in short-term marketable securities that were measured and recorded at fair value on the Company’s balance sheet at December 31, 2023. The Company had approximately $45,423,000 in cash equivalents and $24,675,000 in short-term marketable securities that were measured and recorded at fair value on the Company’s balance sheet at December 31, 2022.

The carrying value of financial instruments (consisting of cash, a certificate of deposit, debt, accounts payable, accrued compensation and accrued expenses) is considered to be representative of their respective fair values due to the short-term nature of those instruments.

Recent Accounting Pronouncements

In June 2016, the FASB issued Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments- Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326) (CECL). The new standard requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. The new standard is effective for annual reporting periods beginning after December 15, 2022, including interim reporting periods within each annual reporting period for smaller reporting companies. The Company adopted ASU 2016-13 but there was no financial impact to the Company's consolidated financial statements for the years ended December 31, 2023 and 2022.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). The guidance in ASU 2023-09 improves the transparency of income tax disclosures by greater disaggregation of information in the rate reconciliation and income taxes paid disaggregated by jurisdiction. The standard is effective for public companies for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact that the adoption of ASU 2023-09 may have on its consolidated financial statements.

Management does not believe that any other recently issued, but not yet effective, authoritative guidance, if currently adopted, would have a material impact on the Company’s financial statement presentation or disclosures.

Marketable Securities - Schedule of Fair Value of Available-for-Sale Marketable Securities (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		$ 24,771,000
Fair Value	$ 0	24,675,000
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		24,771,000
Gross Unrealized Gains		0
Gross Unrealized Losses		(96,000)
Fair Value		$ 24,675,000

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

16. Leases

On March 28, 2022, the Company entered into a License Agreement (the “License”) with MIL 40G, LLC (the “Licensor”), pursuant to which the Company leases approximately 13,000 square feet of office, research and development and laboratory space located at 40 Guest Street, Boston, Massachusetts 02135 (the “Premises”). The Company relocated its corporate headquarters to the Premises in April 2022. On March 28, 2022, the Company terminated its office and lab space lease in Cambridge Massachusetts (the "Laboratory and Office Lease") effective April 30, 2022. The Company performed an analysis of the accounting implications of this termination based on ASC 360 Impairments and Abandonments guidance. For the year ended December 31, 2022, the Company recorded an adjustment to decrease the right-of-use asset and lease liability of approximately $8,124,000 and $8,382,000, respectively, and recorded a gain on right-of-use asset included in the consolidated statement of operations and comprehensive loss of approximately $258,000.

The Company recognized a right of use asset of approximately $9,056,000 and an operating lease liability of approximately $9,056,000 which were recorded as of the Term Commencement Date (as defined below) related to the License.

The term of the License commenced on April 15, 2022 (the “Term Commencement Date”) and expires on April 14, 2026 (the “Term”). The License has a monthly rental rate of $200,700 for the first year of the Term, $208,728 for the second year of the Term, $217,077 for the third year of the Term and $225,760 for the remainder of the Term. Pursuant to the License, the Company prepaid two months of rent and a security deposit. The Licensor is obligated under the License to provide certain services to the Company, including providing certain gases, chemicals and equipment to the Premises’ laboratory space, IT support, security, office support and health and safety training. The Licensor has the right to terminate the License for Cause (as defined in the License).

On May 3, 2022, the Company entered into the First Amendment to the License ("First Amendment”) with the Licensor, pursuant to which the License was expanded to include an additional room effective July 15, 2022. In consideration of the First Amendment, the security deposit was increased from $225,760 to $235,884 effective July 15, 2022. Upon execution of the First Amendment, the Company prepaid three months of rent, two of which will be held in escrow and credited against future rent payments and the other of which was applied to the first month’s rent. Effective July 15, 2022, the monthly rental rate under the First Amendment increased to $209,700 from $200,700. During the year ended December 31, 2022, the Company recognized a right of use asset of approximately $369,000 and a short and long term operating lease liability of approximately $100,300 and $260,600, respectively, using the weighted average discount rate of 8%, which were recorded as of the Term Commencement Date related to the License.

On May 31, 2022, the Company entered into an operating lease for additional laboratory space at 40 Guest Street, Boston, Massachusetts for the period from December 1, 2022, through December 1, 2024 (the “40G Additional Laboratory Lease”). The 40G Additional Laboratory Lease contains escalating payments during the lease period. The monthly rental rate under the 40G Additional Laboratory Lease is $59,152 for the first 12 months and $61,519 for the remainder of the term. Under the terms of this lease agreement, the Company prepaid three months of rent, two of which are held in escrow and will be credited against future rent payments and the other of which was applied to the first month’s rent. During the year ended December 31, 2022, the Company recognized a right of use asset of approximately $1,307,000 and a short and long term operating lease liability of approximately $712,000, and $535,000, respectively, using the weighted average discount rate of 10%, which were recorded as of the Term Commencement Date related to the 40G Additional Laboratory Lease.

On September 9, 2022, the Company terminated its lab space lease in Cambridge, Massachusetts with MIL 21E, LLC with an effective termination date of December 6, 2022. The Company performed an analysis of the accounting implications of this termination based on ASC 360 Impairments and Abandonments guidance. During the year ended December 31, 2022, the Company recorded an entry to remove the remaining lease liability and right of use asset of $963,000 and $945,000, respectively. The difference between the carrying amounts of the right of use asset and lease liability of $19,000 was recorded to gain on right of use asset and included in the consolidated statement of operations and comprehensive loss.

For the year ended December 31, 2023, the Company recorded approximately $512,000 in interest expense to the lease liability.

At December 31, 2023, the Company recorded approximately $6,323,000 to operating lease right-of-use asset, and approximately $3,368,000 and $3,162,000 to the short-term and long-term operating lease liability, respectively. At December 31, 2022, the Company recorded approximately $9,203,000 to operating lease right-of-use asset, and approximately $3,300,000 and $6,018,000 to the short-term and long-term operating lease liability, respectively. As of December 31, 2023 and 2022, a security deposit of approximately of $595,000 and $794,000, respectively, included in deposits on the Company’s consolidated balance sheet related to the 40G Additional Laboratory Lease.

Future minimum lease payments under these leases at December 31, 2023 are as follows:


Year	(in thousands)
2024		3,368
2025		2,799
2026		818
Total lease payments		6,985
Less: present value discount		(455	)
Present value of lease payments	$	6,530

Total rent expense of approximately $3,421,000 and $4,182,000 was included in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2023 and 2022, respectively. Other information pertaining to the Company’s operating leases for the twelve months ended December 31, 2023 is summarized in the table below.

The weighted average remaining lease term and discount rate related to the Company's leases were as follows:


	December 31,
	2023			2022
Weighted average remaining lease term (years)		2.16			3.11
Weighted average discount rate		6.25	%		6.41	%

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

Public Offerings

Issuance of Securities through a Private Placement

Consolidation

The accompanying consolidated financial statements include the Company and its wholly owned subsidiary, Cue Biopharma Securities Corp. The Company has eliminated all intercompany transactions.

Use of Estimates

Cash Concentrations

Cash and Cash Equivalents

Marketable Securities

Restricted Cash

The Company had approximately $150,000 in restricted cash deposited with separate commercial banks to collateralize company credit cards as of December 31, 2023 and 2022.

Property and Equipment


Laboratory equipment		5 years
Computer equipment		3 years
Furniture and fixtures		3-8 years

Trademark

Debt Issuance Costs

Revenue Recognition

the associated event is considered probable of achievement and estimates the amount to be included in the transaction price using the expected value method.

Research and Development Expenses

Patent Expenses

Licensing Fees and Costs

Long-Lived Assets

Leases

Stock-Based Compensation

Income Taxes

Comprehensive Income (Loss)

Earnings (Loss) Per Share


	December 31,
	2023		2022
Common stock warrants		10,719,846		10,719,846
Common stock options		10,800,379		6,740,122
Total		21,520,225		17,459,968

Fair Value of Financial Instruments

Recent Accounting Pronouncements

Summary of Significant Accounting Policies - Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	21,520,225	17,459,968
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	10,719,846	10,719,846
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	10,800,379	6,740,122

Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Outstanding Beginning Balance	6,173,867	5,654,168
Number of shares, granted	2,591,900	828,500
Number of Shares, Exercised	(165,602)	0
Number of Shares, Cancelled	(1,107,248)	(308,801)
Number of Shares, Outstanding Ending Balance	7,492,917	6,173,867	5,654,168
Number of Shares, Exercisable	4,597,265	4,397,991
Weighted Average Exercise Price, Outstanding Beginning Balance	$ 9.6	$ 10.08
Weighted Average Exercise Price, Granted	3.64	6.99
Weighted Average Exercise Price, Exercised	2.86	0
Weighted Average Exercise Price, Cancelled	4.76	11.32
Weighted Average Exercise Price, Outstanding Ending Balance	8.41	9.6	$ 10.08
Weighed Average Exercise Price, Exercisable	$ 10.18	$ 9.04
Weighted Average Remaining Contractual Life (in Years)	6 years 1 month 13 days	5 years 18 days	5 years 5 months 23 days
Weighted Average Remaining Contractual Life (in Years), Exercisable	4 years 6 months
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, granted	320,000

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Depreciation	$ 11,000	$ 11,000
Amortization of capitalized license expense		80,000
Disposal of Gross Assets	2,000	6,000
Laboratory Equipment
Property Plant And Equipment [Line Items]
Disposal of property and equipment, gross	41,000	43,000
Disposal of Gross Assets	1,289,000
Property, Plant and Equipment, Disposals	2,000	6,000
Laboratory Equipment \| Other Income
Property Plant And Equipment [Line Items]
Gain (loss) on disposal of property and equipment	$ 157,000	$ 4,000

Stock-Based Compensation - Schedule of Estimated Fair Value of Each Stock Option Award (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	3.40%	1.53%
Risk-free interest rate, maximum	4.21%	2.92%
Expected dividend yield	0.00%	0.00%
Expected volatility, minimum	97.00%	92.10%
Expected volatility, maximum	114.21%	95.70%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life	5 years 6 months	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life	6 years 3 months	6 years 3 months

- Definition

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

+ References

+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

15. Commitments and Contingencies

Einstein License Agreement

In 2015, the Company entered into the Einstein License Agreement with Einstein for certain patent rights relating to the Company’s core technology platform for the engineering of biologics to control T cell activity, precision, immune-modulatory drug product candidates, and two supporting technologies that enable the discovery of costimulatory signaling molecules (ligands) and T cell targeting peptides. The Company entered into an amended and restated license agreement on July 31, 2017, as amended on October 2018, which modified certain obligations of the parties under the Einstein License Agreement. For the years ended December 31, 2023 and 2022, the Company incurred approximately $7,000 and $0, respectively, in fees payable to Einstein in relation to this license.

The Company’s remaining commitments with respect to the Einstein License are based on the attainment of future milestones. The aggregate amount of milestone payments made under the Einstein License may equal up to $1.85 million for each Licensed Product, and up to $1.85 million for each new indication of a Licensed Product. Additionally, the aggregate amount of one-time milestone payments based on cumulative sales of all Licensed Products may equal up to $5.75 million. The Company is also party to a service agreement with Einstein to support the Company’s ongoing research and development activities.

Collaboration Agreement with LG Chem

See discussion of the LG Chem Collaboration Agreement in Note 11.

Collaboration Agreement with Ono

See discussion of the Ono Collaboration and Option Agreement in Note 11.

Contingencies

The Company accrues contingent liabilities to the extent that the liability is probable and estimable. There are no accruals for contingent liabilities in these consolidated financial statements.

The Company may be subject to various legal proceedings from time to time as part of its business. As of December 31, 2023, the Company was not a party to any legal proceedings or threatened legal proceedings, the adverse outcome of which, individually or in the aggregate, would have a material adverse effect on its business, financial condition or results of operations.

Income Taxes - Schedule of Reconciliation of Gross Uncertain Tax Position (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Balance at the beginning of year	$ 2,491	$ 2,068
Additions for current year tax provisions	424	401
Additions for prior year tax provisions	14	58
Reductions of prior year tax provisions	(2)	(36)
Balance as of end of year	$ 2,927	$ 2,491

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (50,733)	$ (53,010)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (f)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment	$ 4,411	$ 5,741
Less accumulated depreciation	(3,616)	(4,242)
Property and equipment, net	795	1,499
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	4,069	5,246
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	81	81
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	143	296
Leasehold-Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 118	$ 118

Collaboration Revenue - Additional Information (Details) - USD ($)				1 Months Ended		3 Months Ended	12 Months Ended
	Nov. 23, 2021	Dec. 07, 2020	May 16, 2019	Dec. 31, 2020	Jun. 30, 2019	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2018	Feb. 22, 2023	Nov. 06, 2018
Disaggregation Of Revenue [Line Items]
Milestone payment associated with contract liability	$ 3,000,000	$ 1,250,000	$ 2,500,000
Collaboration revenue							$ 5,490,000	$ 1,245,000
Short-term research and development contract liability						$ 2,112,000	2,112,000	0
Prepaid expenses and other short-term assets						1,242,000	1,242,000	841,000
Other long-term assets						117,000	117,000	128,000
Ono Collaboration and Option Agreement [Member]
Disaggregation Of Revenue [Line Items]
Milestone payments received						3,000,000	3,000,000
Collaboration revenue							5,166,000	0
Short-term research and development contract liability						2,112,000	2,112,000
Development and commercial milestone payment payable cuo biopharma											$ 220,000,000
Percentage of right to development and commercialized											50.00%
OneTimeUpFrontPaymentPayableAsConsiderationRDActivities						$ 3,000,000	$ 3,000,000
First Research Term Processed Milestone Payment Under Agreement						18 months	18 months
Maximum \| Ono Collaboration and Option Agreement [Member]
Disaggregation Of Revenue [Line Items]
Full time employe salary payable in first research term						$ 2,100,000	$ 2,100,000
Collaboration Agreement with LG Chem Life Sciences \| LG Chem Life Sciences
Disaggregation Of Revenue [Line Items]
Milestone payments received	3,000,000	1,250,000	2,500,000				6,750,000
Milestone payment associated with contract liability	3,000,000	1,250,000	2,500,000
Collaboration revenue							324,000,000	1,245,000,000
Equity investment nonrefundable upfront cash payment												$ 5,000,000
Equity investment for research collaboration agreement												5,000,000
Income tax expense	$ 495,000	$ 206,250	$ 412,500
Collaboration Agreement with LG Chem Life Sciences \| LG Chem Life Sciences \| Maximum
Disaggregation Of Revenue [Line Items]
Additional amount receivable research development regulatory and sales milestones												$ 400,000,000
Collaboration Agreement with LG Chem Life Sciences \| Einstein
Disaggregation Of Revenue [Line Items]
Prepaid expenses and other short-term assets						$ 0	$ 0	0
Einstein License And Service Agreement \| Einstein
Disaggregation Of Revenue [Line Items]
Patent expenses				$ 157,000	$ 313,000			$ 908,000		$ 438,000
Amortization of Intangible Assets									$ 908,000

Stock-Based Compensation - Schedule of Stock-Based Compensation Included in Statement of Operations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	$ 8,180	$ 9,496
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	3,687	4,615
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	$ 4,493	$ 4,881

Fair Value

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value

3. Fair Value

The Company accounts for its financial assets and liabilities using fair value measurements. The authoritative accounting guidance defines fair value, establishes a framework for measuring fair value under U.S. GAAP and enhances disclosures about fair value measurements. Fair value is defined as the exchange price that would be received for an asset or

paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.

The following table presents information about the Company’s assets that are measured at fair value on a recurring basis as of December 31, 2023 and 2022 and indicate the level of the fair value hierarchy utilized to determine such fair value:


	Fair Value Measurements as of December 31, 2023
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	39,148	$	—	$	—	$	39,148
Marketable securities		—		—		—		—
Total	$	39,148	$	—	$	—	$	39,148

	Fair Value Measurements as of December 31, 2022
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	45,423	$	—	$	—	$	45,423
Marketable securities		24,675		—		—		24,675
Total	$	70,098	$	—	$	—	$	70,098

As of December 31, 2023, the Company reported approximately $39,148,000 and $0 in cash equivalents and marketable securities, respectively. The Company measures the cash equivalents that are invested in money market funds using Level 1 inputs for identical securities. The Company measures the fair value of marketable securities that are invested in U.S. Treasury securities using Level 2 inputs and primarily relies on quoted prices in active markets for similar marketable securities. As of December 31, 2022, the Company reported approximately $45,423,000 and $24,675,000 in cash equivalents and marketable securities, respectively. During the years ended December 31, 2023 and 2022, there were no transfers between Level 2 and Level 3.

- Definition

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

+ References + Details

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Estimated Fair Value of Each Stock Option Award

For stock options requiring an assessment of value during the years ended December 31, 2023 and 2022, the fair value of each stock option award was estimated using the Black-Scholes option-pricing model utilizing the following assumptions:


	December 31,
	2023	2022
Risk-free interest rate	3.40 to 4.21%	1.53 to 2.92%
Expected dividend yield	0%	0%
Expected volatility	97.0-114.21%	92.1-95.7%
Expected life	5.5 to 6.25 years	5.5 to 6.25 years

Summary of Stock Option Activity

A summary of stock option activity for the years ended December 31, 2023 and 2022 is as follows:


	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in Years)
Stock options outstanding at December 31, 2021		5,654,168		$	10.08		5.48
Granted		828,500			6.99
Exercised		—			—
Cancelled		(308,801	)		11.32
Stock options outstanding at December 31, 2022		6,173,867			9.60		5.05
Granted		2,591,900			3.64
Exercised		(165,602	)		2.86
Cancelled		(1,107,248	)		4.76
Stock options outstanding at December 31, 2023		7,492,917			8.41		6.12
Stock options exercisable at December 31, 2023		4,597,265		$	10.18		4.50

Schedule of Stock-Based Compensation Included in Statement of Operations and Comprehensive Loss

Stock-based compensation for the years ended December 31, 2023 and 2022 was included in the consolidated statements of operations and comprehensive loss as follows:


	December 31,
(In thousands)	2023		2022
General and administrative	$	3,687	$	4,615
Research and development		4,493		4,881
Total	$	8,180	$	9,496

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Summary of Property and Equipment

Property and equipment, net as of December 31, 2023 and 2022 consisted of the following:


	December 31,
	2023			2022
	(in thousands)
Laboratory equipment	$	4,069		$	5,246
Furniture and fixtures		81			81
Computer equipment		143			296
Leasehold-Improvements		118			118
Total property and equipment		4,411			5,741
Less accumulated depreciation		(3,616	)		(4,242	)
Property and equipment, net	$	795		$	1,499

Summary of Depreciation Expense

Depreciation expense for the year ended December 31, 2023 was included in the consolidated statements of operations and comprehensive loss as follows, excluding trademark amortization of $11,000. Depreciation expense for the year ended December 31, 2022 was included in the consolidated statements of operations and comprehensive loss as follows, excluding trademark amortization of $11,000 and amortization of capitalized license expenses of $80,000.


	Years Ended December 31,
	2023		2022
	(in thousands)
General and administrative	$	19	$	15
Research and development		526		816
Depreciation total	$	545	$	831

Property and Equipment - Summary of Depreciation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Depreciation Total	$ 545	$ 831
General and Administrative Expense
Property Plant And Equipment [Line Items]
Depreciation Total	19	15
Research and Development
Property Plant And Equipment [Line Items]
Depreciation Total	$ 526	$ 816

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2023

Accrued Liabilities, Current [Abstract]

Summary of Accrued Expenses

Accrued expenses as of December 31, 2023 and 2022 is summarized as follows:


	December 31,
(In thousands)	2023		2022
Employee and board compensation	$	2,219	$	2,273
Contract research services		1,411		1,038
Professional services		344		243
Contract manufacturing services		163		—
Total	$	4,137	$	3,554

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-based compensation

9. Stock-Based Compensation

Effective March 23, 2016, the Company adopted the 2016 Omnibus Incentive Plan (the “Omnibus Plan”) and the 2016 Non-Employee Equity Incentive Plan (the “Non-Employee Plan”), which are intended to allow the Company to compensate and retain the services of key employees, non-employees, Scientific and Clinical Advisory Board members, and outside advisors and consultants. The plans are under the administration of the Company’s Board of Directors. Under the plans, the Company, at its discretion, may grant stock option awards to certain employees and non-employees through March 23, 2026. The Omnibus Plan and the Non-Employee Plan initially provided for the grant of a total of 2,000,000 shares of common stock and 500,000 shares of common stock, respectively.

On August 13, 2017, the Company’s Board of Directors approved an amendment and restatement of the Company’s Omnibus Plan to increase the number of shares authorized for issuance under such plan by 800,000 shares, from 2,000,000 shares to 2,800,000 shares, subject to stockholder approval of such amendment within 12 months following board approval thereof. The Company’s stockholders approved the plan in December 2017. Additionally, on May 17, 2019, the Company’s Board of Directors approved Amendment No. 1 to the Omnibus Plan to increase the number of shares that may be issued as incentive stock options under the plan, which the Company’s stockholders approved on August 6, 2019. The Omnibus Plan, as

amended and restated, provides that on the first day of each fiscal year of the Company during the period beginning in fiscal year ended December 31, 2018 and ending on the second day of fiscal year ending December 31, 2027, the number of shares of common stock authorized to be issued under such plan shall be increased by an amount equal to the lesser of (i) the number of shares necessary such that the aggregate number of shares available to be issued under the plan equals 20% of the number of fully diluted outstanding shares on such date (assuming the conversion of all outstanding shares of preferred stock and other outstanding convertible securities and exercise of all outstanding options and warrants to purchase shares) and (ii) an amount to be determined by the Company’s Board of Directors.

Pursuant to the plans, during the year ended December 31, 2023, the Company granted stock options to purchase 2,591,900 shares of the Company’s common stock, 165,602 shares of common stock were exercised, 1,107,248 shares of common stock were cancelled. At December 31, 2023, stock options for 10,924,521 shares of common stock and 320,000 restricted stock units had been granted and 3,302,062 shares of common stock were reserved for future grants under the Omnibus Plan, and stock options for 494,600 shares of common stock had been granted and 5,400 shares of common stock were reserved for future grants under the Non-Employee Plan. In the aggregate, at December 31, 2023, stock options for a total of 11,419,121 shares of common stock and 320,000 restricted stock units had been granted and 3,307,462 shares of common stock were reserved for future grants. Such grants are accounted for as share-based compensation in accordance with ASC 718, Compensation - Stock Compensation, and ASC 505-50, Equity-Based Payments to Non-Employees.

Stock Option Valuation


	December 31,
	2023	2022
Risk-free interest rate	3.40 to 4.21%	1.53 to 2.92%
Expected dividend yield	0%	0%
Expected volatility	97.0-114.21%	92.1-95.7%
Expected life	5.5 to 6.25 years	5.5 to 6.25 years

The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected term of the stock option award; as permitted by Staff Accounting Bulletin 107, due to insufficient history of stock option activity, management has utilized the simplified approach to estimate the expected term of the stock options, which represents the period of time that stock options granted are expected to be outstanding; the expected volatility is based upon historical volatilities of comparable companies in a similar industry; and the expected dividend yield based upon the Company’s current dividend rate and future expectations.

A summary of stock option activity for the years ended December 31, 2023 and 2022 is as follows:


	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in Years)
Stock options outstanding at December 31, 2021		5,654,168		$	10.08		5.48
Granted		828,500			6.99
Exercised		—			—
Cancelled		(308,801	)		11.32
Stock options outstanding at December 31, 2022		6,173,867			9.60		5.05
Granted		2,591,900			3.64
Exercised		(165,602	)		2.86
Cancelled		(1,107,248	)		4.76
Stock options outstanding at December 31, 2023		7,492,917			8.41		6.12
Stock options exercisable at December 31, 2023		4,597,265		$	10.18		4.50

The Company recognized $8,180,030 and $8,649,803, in stock-based compensation expense during the years ended December 31, 2023 and 2022, respectively. As of December 31, 2023, total unrecognized stock-based compensation was approximately $10,049,000, which is expected to be recognized as an operating expense in the Company’s consolidated statements of operations and comprehensive loss through December 2025 or 2 years.

The aggregate intrinsic value of exercisable but unexercised in-the-money stock options of 4,597,265 at December 31, 2023 was approximately $594 based on a weighted average exercise price of $10.18 per share. The aggregate intrinsic value of options is calculated as the difference of the market close price of $2.64 on December 31, 2023, and the weighted average exercise price of $10.18, with a weighted average remaining contractual term of 4.5 years.

The aggregate intrinsic value of exercisable but unexercised in-the-money stock options of 4,397,991 at December 31, 2022 was approximately $0 based on a weighted average exercise price of $9.04 per share. The aggregate intrinsic value of options is calculated as the difference of the market close price of $2.85 on December 31, 2022, and the weighted average exercise price of $9.04, with a weighted average remaining contractual term of 3.74 years.

Restricted Stock Units

On October 3, 2019, the Company granted 100,000 restricted stock units (“RSUs”) with time-based vesting conditions to an executive officer having an average grant date fair value of $7.53 per share. The RSUs vested in three equal installments beginning on the grant date, and annually on each anniversary of the grant date thereafter. Compensation expense is recognized on a straight-line basis.

On February 5, 2020, the Company granted 150,000 RSUs with time-based vesting conditions to an executive officer. One-half of the RSUs vested on September 30, 2021, and the balance vested on March 31, 2022. On March 31, 2020, the Company granted 50,000 RSUs with time-based vesting conditions to an executive officer. The RSUs vested in three equal installments beginning on the grant date, and annually on each anniversary of the grant date thereafter. Compensation expense is recognized on a straight-line basis.

On August 21, 2020, the Company granted 20,000 RSUs with time-based vesting conditions to an executive officer. The RSUs vest in three equal installments beginning on the grant date, and annually on each anniversary of the grant date thereafter, subject to the recipient’s continued service on each applicable vesting date. Compensation expense is recognized on a straight-line basis.

The Company recognized $0 and $846,073 in stock-based compensation during the years ended December 31, 2023 and 2022, respectively, related to RSU activity. As of December 31, 2023, total unrecognized stock-based compensation related to RSU activity was $0.

Stock-based Compensation

Stock-based compensation for the years ended December 31, 2023 and 2022 was included in the consolidated statements of operations and comprehensive loss as follows:


	December 31,
(In thousands)	2023		2022
General and administrative	$	3,687	$	4,615
Research and development		4,493		4,881
Total	$	8,180	$	9,496

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Percentage of valuation allowance against deferred tax assets	100.00%
Unrecognized tax benefits	$ 2,927,000	$ 2,491,000	$ 2,068,000
Federal
Income Taxes [Line Items]
Operating loss carryforwards	$ 196,100,000
Operating loss carryforwards expiration start year	2035
Net operating losses indefinite carryforward amount	$ 167,500,000
State
Income Taxes [Line Items]
Operating loss carryforwards	$ 193,500,000
Research Tax Credit \| Federal
Income Taxes [Line Items]
Operating loss carryforwards expiration start year	2035
Tax credits	$ 8,400,000
Research Tax Credit \| State
Income Taxes [Line Items]
Tax credits	2,400,000
Tax Credit Indefinite Carryforward Amount	$ 100,000
Tax credits carryforward expiration start year	2033
Maximum [Member] \| Research Tax Credit \| Federal
Income Taxes [Line Items]
Unrecognized tax benefits	$ 2,927,000	$ 2,491,000

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Gain	Accumulated Deficit
Balance at Dec. 31, 2021	$ 65,492	$ 32	$ 262,907		$ (197,447)
Balance, Shares at Dec. 31, 2021		32,202,496
Issuance of common stock from ATM offering, net of sales agent commission and fees, Shares		3,117,220
Issuance of common stock from ATM offering, net of sales agent commission and fees, Amount	16,598	$ 3	16,595
Stock-based compensation	$ 9,496		9,496
Exercise of stock options, Shares	0
Restricted stock awards	$ 0	$ 0	(0)
Restricted stock award, Shares		98,335
Repurchase of restricted stock awards	(200)	$ 0	(200)
Repurchase of restricted stock awards, Shares		(42,018)
Issuance of common stock upon exercise of warrants, net, Shares		9,549
Issuance of common stock upon exercise of warrants, net, Amount		$ 0	(0)
Unrealized gains from available-for-sale securities	(96)			$ (96)
Issuance of common stock and pre-funded warrants, net of issuance costs (In Shares)		7,656,966
Issuance of common stock and pre-funded warrants, net of issuance costs	27,402	$ 8	27,394
Net Income (Loss)	(53,010)				(53,010)
Balance at Dec. 31, 2022	65,682	$ 43	316,192	(96)	(250,457)
Balance, Shares at Dec. 31, 2022		43,042,548
Stock-based compensation	8,180		8,180
Exercise of stock options	$ 473		473
Exercise of stock options, Shares	165,602	165,602
Issuance of common stock from public offerings, net of underwriter commissions and fees	$ 13,387	$ 4	13,383
Issuance of common stock from public offerings, net of underwriter discounts, Shares	7,656,966	4,006,966
Unrealized gains from available-for-sale securities	$ 96			96
Net Income (Loss)	(50,733)				(50,733)
Balance at Dec. 31, 2023	$ 37,085	$ 47	$ 338,228	$ 0	$ (301,190)
Balance, Shares at Dec. 31, 2023		47,215,116

Stockholders' Equity - Additional Information (Details) - $ / shares		12 Months Ended
	Nov. 14, 2022	Dec. 31, 2023	Dec. 31, 2022	Nov. 16, 2022
Preferred stock, shares authorized		10,000,000	10,000,000
Preferred stock, par value		$ 0.001	$ 0.001
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, shares authorized		100,000,000	100,000,000
Common stock, par value		$ 0.001	$ 0.001
Common stock, shares issued		43,042,548	47,215,116
Common stock, shares outstanding		43,042,548	47,215,116
Stock Issued During Period, Shares, New Issues		7,656,966
Common Stock, Par or Stated Value Per Share		$ 0.001	$ 0.001
Common Stock [Member]
Common stock, shares issued		47,215,116
Common stock, shares outstanding		47,215,116
Sale of Stock, Price Per Share	$ 3.265
Stock Issued During Period, Shares, New Issues		4,006,966
Warrant [Member]
Common stock, shares issued	1,531,440
Purchase of Additional Shares Of Common Stock	9,188,406
Sale of Stock, Price Per Share	$ 3.2649
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 3.93			$ 3.93
Private Placement [Member] \| Common Stock [Member] \| Investor [Member]
Common stock, shares issued	7,656,966
Private Placement [Member] \| Warrant [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 3.9299

Fair Value - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value assets transfers between Level 2 and Level 3	$ 0	$ 0
Cash equivalents and marketable securities	39,148,000	45,423,000
Marketable securities	0	$ 24,675,000
Marketable securities	$ 0

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Schedule of Fair Value of Available-for-Sale Marketable Securities

As of December 31, 2023, the Company did not hold any marketable securities. The fair value of the Company's marketable securities was $24,675,000 at December 31, 2022. The following table presents the Company's marketable securities at December 31, 2022:


	December 31, 2022
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury Securities	$	24,771	$	—	$	(96	)	$	24,675

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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-Section 50
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+ Details

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Estimated Useful Lives of Assets

Depreciation of property and equipment is provided using the straight-line method over the following estimated useful lives:


Laboratory equipment		5 years
Computer equipment		3 years
Furniture and fixtures		3-8 years

Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share


	December 31,
	2023		2022
Common stock warrants		10,719,846		10,719,846
Common stock options		10,800,379		6,740,122
Total		21,520,225		17,459,968

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Income Taxes - Schedule of Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 53,376	$ 49,708
Research and other credits	7,482	5,841
R&D Capitalization	16,181	8,183
Reserves and accruals	8,519	8,574
Other	270	291
Total gross deferred tax assets	85,828	72,597
Less valuation allowance	(84,039)	(70,010)
Total deferred tax assets	1,789	2,587
Deferred tax liability:
Depreciation	(1,789)	(2,587)
Other	0	0
Deferred Tax Assets, Net	$ 0	$ 0

Fair Value (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Fair Value Assets Measured on Recurring Basis


	Fair Value Measurements as of December 31, 2023
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	39,148	$	—	$	—	$	39,148
Marketable securities		—		—		—		—
Total	$	39,148	$	—	$	—	$	39,148

	Fair Value Measurements as of December 31, 2022
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	45,423	$	—	$	—	$	45,423
Marketable securities		24,675		—		—		24,675
Total	$	70,098	$	—	$	—	$	70,098

Related Party Transactions

12 Months Ended

Dec. 31, 2023

Related Party Transactions

13. Related Party Transactions

Information with respect to payments under the Einstein License is described in Note 8.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

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+ Details

Stockholders' Equity

12 Months Ended

Dec. 31, 2023

Equity, Attributable to Parent [Abstract]

Stockholders' Equity

12. Stockholders’ Equity

Preferred Stock

The Company has authorized a total of 10,000,000 shares of preferred stock, par value $0.001 per share, none of which were outstanding at December 31, 2023 and 2022. The Company’s Board of Directors has the authority to issue preferred stock and to determine the rights, preferences, privileges, and restrictions, including voting rights.

Common Stock

The Company has authorized a total of 100,000,000 shares of common stock, par value $0.001 per share, of which 47,215,116 shares and 43,042,548 shares were issued and outstanding at December 31, 2023 and 2022, respectively.

Warrants

Information with respect to warrants and pre-funded warrants issued is described in Note 10.

- Definition

The entire disclosure for equity.

+ References

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

Cue Biopharma 401(k) Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Company Contribution	$ 272,000	$ 245,000

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2023	Mar. 25, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	CUE
Entity Registrant Name	Cue Biopharma, Inc.
Entity Central Index Key	0001645460
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		48,643,316
Entity Public Float			$ 154.4
Entity Interactive Data Current	Yes
ICFR Auditor Attestation Flag	false
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-38327
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3324577
Entity Address, Address Line One	40 Guest Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02135
City Area Code	617
Local Phone Number	949-2680
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	The registrant intends to file a definitive proxy statement pursuant to Regulation 14A within 120 days after the end of the fiscal year ended December 31, 2023. Portions of such proxy statement are incorporated by reference into Part III of this Form 10-K.
Auditor Name	RSM US LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	49
Document Financial Statement Error Correction [Flag]	false

Summary of Significant Accounting Policies - Summary of Estimated Useful Lives of Assets (Details)	Dec. 31, 2023
Laboratory Equipment
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Estimated useful lives	3 years
Furniture and Fixtures \| Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	3 years
Furniture and Fixtures \| Maximum
Property Plant And Equipment [Line Items]
Estimated useful lives	8 years

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	43,042,548	47,215,116
Common stock, shares outstanding	43,042,548	47,215,116

Marketable Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable securities	$ 24,675,000	$ 0
Marketable securities of investments	24,771,000
Unrealized gain on investments	$ 96,000
Marketable securities, Maturity period	12 months

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Collaboration revenue	$ 5,490	$ 1,245
Operating expenses (income):
General and administrative	16,680	16,169
Research and development	40,802	38,578
Loss (gain) on fixed asset disposal and right-of-use asset termination	157	(277)
Total operating expenses	57,639	54,470
Loss from operations	(52,149)	(53,225)
Other income (expense):
Interest income	2,661	928
Interest expense	(1,245)	(713)
Total other income	1,416	215
Net loss	(50,733)	(53,010)
Unrealized loss from available-for-sale securities	96	(96)
Comprehensive loss	$ (50,637)	$ (53,106)
Net loss per common share - basic	$ (1.11)	$ (1.49)
Net loss per common share - diluted	$ (1.11)	$ (1.49)
Weighted average common shares outstanding, basic	45,754,794	35,649,134
Weighted average common shares outstanding, diluted	45,754,794	35,649,134

Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Employee and board compensation	$ 2,219	$ 2,273
Contract manufacturing services	163	0
Professional services	344	243
Contract research services	1,411	1,038
Accrued expenses	$ 4,137	$ 3,554

Marketable Securities

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

4. Marketable Securities


	December 31, 2022
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury Securities	$	24,771	$	—	$	(96	)	$	24,675

At December 31, 2023, the Company did not have marketable securities. At December 31, 2022, the Company's marketable securities consisted of $24,771,000 of investments that matured within 12 months and the Company recorded an unrealized loss on investments of $96,000 for the year ended December 31, 2022.

Stock-Based Compensation - Additional Information (Details) - USD ($)				1 Months Ended	12 Months Ended
	Feb. 05, 2020	Oct. 03, 2019	Aug. 13, 2017	Mar. 31, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Aug. 21, 2020	Aug. 12, 2017	Mar. 23, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					2,591,900	828,500
Number of Shares, Exercised					(165,602)	0
Number of Shares, Cancelled					(1,107,248)	(308,801)
Common stock reserved for issuance					3,307,462
Stock options exercisable					4,597,265	4,397,991
Stock-based compensation					$ 8,180	$ 9,496
Unrecognized stock-based compensation					10,049,000
Intrinsic value of exercisable stock options					$ 594	$ 0
Intrinsic value of exercisable fair value per share					$ 10.18	$ 9.04
Fair value of option					2.64	2.85
Weighed Average Exercise Price, Exercisable					$ 10.18	$ 9.04
Stock based payment options outstanding weighted average remaining term					6 years 1 month 13 days	5 years 18 days	5 years 5 months 23 days
Stock-based compensation					$ 8,180,000	$ 9,496,000
Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation					$ 8,180,030	$ 8,649,803
Stock based payment options outstanding weighted average remaining term					2 years
Stock Option \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based payment options outstanding weighted average remaining term					4 years 6 months	3 years 8 months 26 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation					$ 0
Unvested share purchase		100,000							20,000
Weighted average grant date fair value per share		$ 7.53
Stock-based compensation					$ 0	$ 846,073
Restricted Stock Units \| February2020 Awarded And Granted
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	150,000
Restricted Stock Units \| March2020 Awarded And Granted
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted				50,000
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					320,000
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					2,591,900
Number of Shares, Exercised					(165,602)
Number of Shares, Cancelled					(1,107,248)
Common Stock \| Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					11,419,121
Two Thousand Sixteen Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance					3,302,062
Two Thousand Sixteen Omnibus Incentive Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					320,000
Two Thousand Sixteen Omnibus Incentive Plan \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized											2,000,000
Number of shares, granted					10,924,521
2016 Non-Employee Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					494,600
Common stock reserved for issuance					5,400
2016 Non-Employee Equity Incentive Plan \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized											500,000
Omnibus Plan \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized			2,800,000							2,000,000
Number of additional shares authorized for issuance			800,000
Percentage of number of common stock outstanding								20.00%

Leases - Schedule of Future Minimum Lease Payments on Operating Leases (Details)	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 3,368
2025	2,799
2026	818
Total lease payments	6,985
Less: present value discount	(455)
Present value of lease payments	$ 6,530

Einstein License and Service Agreement

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Einstein License and Service Agreement

8. Einstein License and Service Agreement

License Agreement

On January 14, 2015, the Company entered into a license agreement, as amended on June 2, 2015 (the “Einstein License”), with Albert Einstein College of Medicine (“Einstein”) for certain patent rights relating to the Company’s core technology platform for the engineering of biologics to control T cell activity, precision, immune-modulatory drug product candidates, and two supporting technologies that enable the discovery of costimulatory signaling molecules (ligands) and T-cell targeting peptides. On July 31, 2017, the Company entered into an amended and restated license agreement which modified certain obligations of the parties under the Einstein License.

Under the Einstein License, the Company holds an exclusive worldwide license, with the right to sublicense, import, make, have made, use, provide, offer to sell, and sell all products, processes and services that use the patents covered by the Einstein License, including certain technology received from Einstein relating thereto (the “Licensed Products”). Under the Einstein License, the Company is required to:

•

Pay royalties and amounts based on a certain percentage of proceeds, as defined in the Einstein License, from sales of Licensed Products and sublicense agreements.

•

Pay escalating annual maintenance fees, which are nonrefundable, but are creditable against the amount due to Einstein for royalties.

•

Make significant payments based upon the achievement of certain milestones, as defined in the Einstein License. Payments made upon achievement of milestones are nonrefundable and are not creditable against any other payment due to Einstein. At December 31, 2023, the Company has made aggregate payments totaling $1,233,000 since inception with respect to achievement of these milestones.

•

Incur minimum product development costs until the first commercial sale of the first licensed product.

The Company was in compliance with its obligations under the Einstein License at December 31, 2023 and 2022.

The Einstein License expires upon the expiration of the Company’s last obligation to make royalty payments to Einstein which may be due with respect to certain Licensed Products, unless terminated earlier under the provisions thereof. The Einstein License includes certain termination provisions if the Company fails to meet its obligations thereunder.

Pursuant to the Einstein License, the Company issued to Einstein 671,572 shares of the Company’s common stock in connection with the consummation of the initial public offering of its common stock on December 27, 2017.

The Company accounts for license fees incurred in connection with the Einstein License in accordance with ASC 730, Research and Development. Please refer to Note 11 Collaboration Revenue.

Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Nov. 16, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 26, 2022	Nov. 14, 2022	Jun. 15, 2022	Dec. 27, 2017	Jun. 15, 2015
Class Of Warrant Or Right [Line Items]
Common stock warrants expiration date		Jun. 15, 2015
Common stock, shares issued		43,042,548	47,215,116
Shares of common stock		7,656,966
Warrants purchase shares of common stock		9,188,406
Pre Funded Warrants		1,531,440
Tranche 1
Class Of Warrant Or Right [Line Items]
Common stock warrants outstanding								1,500
Exercise price of common stock warrants								$ 2.7
Common stock warrants life						7 years
Common stock warrants expiration date		Jun. 15, 2022
Warrant
Class Of Warrant Or Right [Line Items]
Common stock warrants outstanding	9,188,406
Exercise price of common stock warrants	$ 3.93				$ 3.93
Common stock warrants life	5 years
Common stock, shares issued					1,531,440
Tranche 2
Class Of Warrant Or Right [Line Items]
Common stock warrants outstanding							882,071
Exercise price of common stock warrants							$ 9.38
Common stock warrants life				5 years
Common stock warrants expiration date		Dec. 26, 2022
Tranche 3
Class Of Warrant Or Right [Line Items]
Pre Funded Warrants		1,531,440
Pre-Funded Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of common stock warrants	$ 0.0001	$ 3.93
Additional Paid In Capital Warrant Issued		$ 27,394,687
Pre Funded Warrants	1,531,440
Placement fees		$ 2,597,649

Income Taxes - Schedule of Reconciliation of Federal Statutory Rate and Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U. S. federal statutory tax rate	(21.00%)	(21.00%)
State taxes	(6.00%)	(6.00%)
Change in valuation allowance	28.00%	29.00%
Tax credits	(3.00%)	(4.00%)
Stock based compensation	2.00%	1.00%
Foreign withholding taxes	0.00%	0.00%
Other	0.00%	1.00%
Effective tax rate	0.00%	0.00%

Subsequent Events

12 Months Ended

Dec. 31, 2023

Subsequent Events [Abstract]

Subsequent Events

18. Subsequent Events

ATM Sales

Subsequent to December 31, 2023, the Company sold 1,428,200 shares of common stock under the October 2021 ATM Agreement for proceeds of approximately $3.4 million, net of commissions paid, but excluding transactions expenses. As of March 28, 2024, aggregate sales under the October 2021 ATM Agreement totaled 9,028,573 shares of common stock sold for approximately $40.4 million, net of commissions paid, but excluding estimated transaction expenses.

Organization and Basis of Presentation - Additional Information (Details) $ in Millions	Dec. 31, 2023 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Marketable Securities	$ 48.5

Property and Equipment

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment

5. Property and Equipment, Net

Property and equipment, net as of December 31, 2023 and 2022 consisted of the following:


	December 31,
	2023			2022
	(in thousands)
Laboratory equipment	$	4,069		$	5,246
Furniture and fixtures		81			81
Computer equipment		143			296
Leasehold-Improvements		118			118
Total property and equipment		4,411			5,741
Less accumulated depreciation		(3,616	)		(4,242	)
Property and equipment, net	$	795		$	1,499


	Years Ended December 31,
	2023		2022
	(in thousands)
General and administrative	$	19	$	15
Research and development		526		816
Depreciation total	$	545	$	831

During the year ended December 31, 2023, the Company sold fully depreciated lab equipment with an acquisition cost of $41,000 and collected cash of $2,000, and disposed of gross assets of $1,289,000. The Company recorded a loss on the sale of fixed assets of $157,000, which is presented in operating expenses on the consolidated statements of operations and comprehensive loss. During the year ended December 31, 2022, the Company sold furniture and fixtures and lab equipment with an acquisition cost of $43,000 and collected cash of $6,000, and recorded a loss on the sale of fixed assets of $4,000.

Loan with First Citizens Bank (formerly with Silicon Valley Bank)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Loan with First Citizens Bank (formerly with Silicon Valley Bank)

6. Loan with First Citizens Bank (formerly with Silicon Valley Bank)

On February 15, 2022 (the “Closing Date”), the Company entered into a Loan and Security Agreement (the “Loan Agreement”), with Silicon Valley Bank, as lender (“SVB”). The Company drew $10,000,000 in term loans under the Loan Agreement (the "Term Loans") on the Closing Date. The Loan Agreement was amended in April 2023.

The Term Loans bear interest at a floating rate per annum equal to the greater of (A) the prime rate (as published in the money rates section of The Wall Street Journal) plus 2.25% and (B) 5.50%. The Term Loans were interest only from the Closing Date through June 30, 2023, after which the Company is required to pay 30 equal monthly installments of principal. At December 31, 2023, the interest rate was 10.75% which is based on the prime rate plus 2.25%.

The Term Loans may be prepaid in full prior to February 15, 2024 with payment of a 2.00% prepayment premium, on or after which they may be prepaid in full with payment of a 1.00% prepayment premium. Upon prepayment or repayment in full of the Term Loans, the Company will be required to pay a one-time final payment fee equal to 5.00% of the original principal amount of any funded Term Loans being repaid. This one-time final payment fee is recorded to interest expense using the effective interest method over the period of the Term Loans in the consolidated statements of operation and other comprehensive loss.

The Term Loans and related obligations under the Loan Agreement are secured by substantially all of the Company’s properties, rights and assets, except for its intellectual property which is subject to a negative pledge under the Loan Agreement.

The Loan Agreement contains customary representations, warranties, events of default and covenants, including a requirement that the Company maintain in accounts of the Company at SVB unrestricted and unencumbered cash equal to the lesser of all of the Company’s cash or $20,000,000. On March 10, 2023, SVB was closed and the FDIC was appointed receiver for the bank. The FDIC created a successor bridge bank, and all deposits and loans of SVB were transferred to the bridge bank under a systemic risk exception approved by the United States Department of the Treasury, the Federal Reserve and the FDIC. On March 27, 2023, First Citizens Bank & Trust Company (“First Citizens Bank”), assumed all of SVB’s deposits and certain other liabilities and acquired substantially all of SVB’s loans and certain other assets from the FDIC. First Citizens Bank continues to hold the Company’s Term Loans under the same existing terms and covenants which were in place with SVB.

During the years ended December 31, 2023 and 2022, the Company recognized interest expense related to the Term Loans of $1,003,000 and $570,000, respectively, and $130,000 and $109,000, respectively, in interest expense related to accretion of the final repayment.


The following table presents the aggregate maturities of Long-term debt as of December 31, 2023 (in thousands):

Year
2024	$	4,000
2025		4,000
Total	$	8,000

The following table presents long-term and current portions of debt as of December 31, 2023 (in thousands):

Long-term debt	$	4,000
Accretion of final payment		239
Less: unamortized debt issuance costs		(37	)
Long-term debt, net	$	4,202
Current portion of long-term debt	$	4,000
Less: unamortized debt issuance costs		(37	)
Current portion of long-term debt, net	$	3,963

Debt Issuance Costs

Debt issuance costs are deferred and presented as a reduction to long-term debt. Debt issuance costs are amortized using the effective interest rate method over the term of the loan. Amortization of deferred debt issuance costs are included in interest expense in the consolidated statements of operations and comprehensive loss. The Company incurred approximately $142,000 in debt issuance costs related to the Loan Agreement. For the years ended December 31, 2023 and 2022, the Company recorded approximately $37,000 and $31,000, respectively, in amortization of debt issuance costs to interest expense in the consolidated statements of operations and comprehensive loss. The Company recorded $37,000 to both short- and long-term debt issuance costs contra-liabilities as of December 31, 2023.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
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-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1B
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 1B
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1E
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (a)
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 1I
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

14. Income Taxes

The Company accounts for income taxes under the provision of ASC 740, Income Taxes. The Company did not report a tax provision for the years ended December 31, 2023 and 2022 due to historically incurred net operating losses.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets as of December 31, 2023 and 2022 are as follows:


	December 31,
(In thousands)	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	53,376		$	49,708
Research and other credits		7,482			5,841
R&D capitalization		16,181			8,183
Reserves and accruals		8,519			8,574
Other		270			291
Total gross deferred tax assets		85,828			72,597
Less valuation allowance		(84,039	)		(70,010	)
Total deferred tax assets		1,789			2,587
Deferred tax liability:
Depreciation		(1,789	)		(2,587	)
Other		—			—
Net deferred tax assets	$	—		$	—

In assessing the potential realization of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the Company attaining future taxable income during the periods in which those temporary differences become deductible. As of December 31, 2023, and 2022, management was unable to determine if it is more likely than not that the Company’s deferred tax assets will be realized and has therefore recorded a 100% valuation allowance against deferred tax assets at such dates.

No Federal tax provision has been provided for the years ended December 31, 2023 and 2022 due to the losses incurred during such periods. A reconciliation of the difference between the income tax rate computed by applying the U.S. Federal statutory rate and the effective tax rate for the years ended December 31, 2023 and 2022 is as follows:


	December 31,
	2023			2022
U. S. federal statutory tax rate		(21	)%		(21	)%
State taxes		(6	)%		(6	)%
Change in valuation allowance		28	%		29	%
Tax credits		(3	)%		(4	)%
Stock-based compensation		2	%		1	%
Foreign withholding taxes		0	%		0	%
Other		0	%		1	%
Effective tax rate		0	%		0	%

On October 4, 2023, Massachusetts enacted tax law changes which included the adoption of a single sales apportionment factor effective on January 1, 2025. As required under ASC 740, the Company has accounted for the deferred tax impacts of this tax law change in the period the tax law was enacted, which resulted in an insignificant increase in state deferred tax assets and offset with a valuation allowance.

The Company has applied the provisions of ASC 740, which clarifies the accounting for uncertainty in tax positions and requires the recognition of the impact of a tax position in the financial statements if that position is more likely than not of being sustained on a tax return, based on the technical merits of the position, upon examination by the relevant taxing authority. At December 31, 2023 and 2022, the Company had unrecognized tax benefits related to Federal and state research tax credits of approximately $2,927,000 and $2,491,000, respectively. The Company is subject to Federal and state income tax examinations by tax authorities for all years since its incorporation in 2014. The Company is currently not under examination by any tax authority.

At December 31, 2023, the Company has available net operating loss carryforwards for Federal and state income tax purposes of approximately $196.1 million and $193.5 million, respectively, which, if not utilized earlier, will begin to expire in 2035. Approximately $167.5 million of the federal net operating losses have an indefinite carryforward. The Company has Federal research credits of approximately $8.4 million, which, if not utilized earlier, will begin to expire in 2035, and state research credits of approximately $2.4 million, which, if not utilized earlier, will begin to expire in 2033. Approximately $0.1 million of the state research credits have an indefinite carryforward.

The following is a reconciliation of the Company’s gross uncertain tax position at December 31, 2023 and 2022:


	December 31,
(In thousands)	2023			2022
Balance at the beginning of year	$	2,491		$	2,068
Additions for current year tax provisions		424			401
Additions for prior year tax provisions		14			58
Reductions of prior year tax provisions		(2	)		(36	)
Balance as of end of year	$	2,927		$	2,491

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
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-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Loan with First Citizens Bank (formerly with Silicon Valley Bank) - Additional Information (Details) - USD ($)			12 Months Ended
	Feb. 15, 2025	Feb. 15, 2024	Dec. 31, 2023	Dec. 31, 2022	Feb. 15, 2022
Line of Credit Facility [Line Items]
Short-Term Debt			$ 37,000
Interest Expense			130,000	$ 109,000
Cash Obligation			20,000,000
Interest Expense, Other			1,003,000	570,000
Debt Issuance Costs, Net, Total			142,000
Amortization of Debt Issuance Costs			$ 37,000	$ 31,000
Silicon Valley Bank [Member]
Line of Credit Facility [Line Items]
Prepayment premium rate	1.00%	2.00%
Debt Instrument Final Fee		5.00%
Silicon Valley Bank [Member] \| Tranche A loan [Member]
Line of Credit Facility [Line Items]
Monthly installments			30 months
Silicon Valley Bank [Member] \| Term Loan Agreement [Member]
Line of Credit Facility [Line Items]
Short-Term Debt					$ 10,000,000
Debt Instrument, Basis Spread on Variable Rate			2.25%
Debt Instrument, Convertible, Conversion Date			Jun. 30, 2023
Interest rate			10.75
Silicon Valley Bank [Member] \| Term Loan Agreement [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate			5.50%
Silicon Valley Bank [Member] \| Term Loan Agreement [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate			2.25%

Leases - Additional Information (Details)	12 Months Ended
Leases - Additional Information (Details)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	May 31, 2022 USD ($)	May 03, 2022 USD ($)	Mar. 28, 2022 USD ($) ft²
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	$ 6,323,000	$ 9,203,000
Operating Lease, Liability	$ 6,530
Weighted average discount rate	6.25%	6.41%
Operating Lease, Liability, Current	$ 3,368,000	$ 3,300,000
Operating Lease, Liability, Noncurrent	3,162,000	6,018,000
Operating Leases, Rent Expense, Net	3,421,000	4,182,000
Finance Lease, Interest Expense	512,000
Gain On Right Of Use Asset Termination	(157,000)	$ 277,000
License Agreement Terms [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	9,056,000
Operating Lease, Liability	9,056,000
Weighted average discount rate		8.00%
Security Deposit Liability				$ 225,760
License monthly rental rate first year					$ 200,700
License monthly rental rate second year					208,728
License monthly rental rate third year					217,077
License monthly rental rate remainder of the term				200,700	$ 225,760
Increase in security deposit				235,884
License monthly rental rate				$ 209,700
ASU 2016-02
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	6,323,000	$ 9,203,000
Operating Lease, Liability, Current	3,368,000	3,300,000
Operating Lease, Liability, Noncurrent	3,162,000	6,018,000
Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Office space for lease \| ft²					13,000
Additional Laboratory Lease Fourth Amendment Member
Lessee, Lease, Description [Line Items]
Loss on Right Of Use Asset		258,000
Adjustment related to right of use asset		8,124,000
Adjustment related to lease liability		8,382,000
Lab Space Lease [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset		945,000
Operating Lease, Cost		963,000
Gain On Right Of Use Asset Termination	19,000
First Amendment [Member] \| License Agreement Terms [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset		369,000
Operating Lease, Liability, Current		100,300
Operating Lease, Liability, Noncurrent		260,600
Operating Lease Agreement For Additional Laboratory Space [Member] \| Boston [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset		$ 1,307,000
Lessee operating lease monthly rental payments for remaining term			$ 61,519
Lessee Operating Lease Monthly Rental Payments			$ 59,152
Weighted average discount rate		10.00%
Operating Lease, Liability, Current		$ 712,000
Operating Lease, Liability, Noncurrent		535,000
Forty G Office and Additional Laboratory [Member]
Lessee, Lease, Description [Line Items]
Security Deposit Liability	$ 595,000	$ 794,000

Cue Biopharma 401(k) Plan

12 Months Ended

Dec. 31, 2023

Retirement Benefits [Abstract]

Cue Biopharma 401(k) Plan

17. Cue Biopharma 401(k) Plan

Effective as of January 1, 2017, the Company adopted the Cue Biopharma 401(k) Plan (the “Plan”) for all employees of the Company. Employees may participate in the Plan upon complying with the Plan’s eligibility requirements, subject to limitations imposed by the Internal Revenue Service. Under the Plan, the Company may match employee contributions at its discretion. The Company made contributions of approximately $272,000 and $245,000 to the Plan during the years ended December 31, 2023 or 2022, respectively.

Fair Value - Schedule of Fair Value Assets Measured on Recurring Basis (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 39,148,000	$ 45,423,000
Marketable securities	0	24,675,000
Cash equivalents and marketable securities	39,148,000	45,423,000
Fair Value Measurements, Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	39,148,000	45,423,000
Marketable securities	0	24,675,000
Cash equivalents and marketable securities	39,148,000	70,098,000
Fair Value Measurements, Recurring Basis \| Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	39,148,000	45,423,000
Marketable securities	0	24,675,000
Cash equivalents and marketable securities	39,148,000	70,098,000
Fair Value Measurements, Recurring Basis \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Cash equivalents and marketable securities	0	0
Fair Value Measurements, Recurring Basis \| Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Cash equivalents and marketable securities	$ 0	$ 0

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets as of December 31, 2023 and 2022 are as follows:


	December 31,
(In thousands)	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	53,376		$	49,708
Research and other credits		7,482			5,841
R&D capitalization		16,181			8,183
Reserves and accruals		8,519			8,574
Other		270			291
Total gross deferred tax assets		85,828			72,597
Less valuation allowance		(84,039	)		(70,010	)
Total deferred tax assets		1,789			2,587
Deferred tax liability:
Depreciation		(1,789	)		(2,587	)
Other		—			—
Net deferred tax assets	$	—		$	—

Schedule of Reconciliation of Federal Statutory Rate and Effective Tax Rate


	December 31,
	2023			2022
U. S. federal statutory tax rate		(21	)%		(21	)%
State taxes		(6	)%		(6	)%
Change in valuation allowance		28	%		29	%
Tax credits		(3	)%		(4	)%
Stock-based compensation		2	%		1	%
Foreign withholding taxes		0	%		0	%
Other		0	%		1	%
Effective tax rate		0	%		0	%

Schedule of Reconciliation of Gross Uncertain Tax Position

The following is a reconciliation of the Company’s gross uncertain tax position at December 31, 2023 and 2022:


	December 31,
(In thousands)	2023			2022
Balance at the beginning of year	$	2,491		$	2,068
Additions for current year tax provisions		424			401
Additions for prior year tax provisions		14			58
Reductions of prior year tax provisions		(2	)		(36	)
Balance as of end of year	$	2,927		$	2,491

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)			12 Months Ended
	Nov. 16, 2022	Nov. 14, 2022	Dec. 31, 2023	Dec. 31, 2022
Summary Of Significant Accounting Policies [Line Items]
Shares of common stock			7,656,966
Pre Funded Warrants			1,531,440
Acquired intangible asset, useful life			15 years
Type of Cost, Good or Service [Extensible List]			us-gaap:LicenseMember
Disposal of Gross Assets			$ 2,000	$ 6,000
Operating lease, right-of-use asset			6,323,000	9,203,000
Operating lease, liability			6,530
Cash equivalents			39,148,000	45,423,000
Marketable securities			0	$ 24,675,000
Marketable securities			$ 0
Common stock, par value			$ 0.001	$ 0.001
Proceed From Pre Funded Warrants Financing		$ 30,000,000
Placement Agent Fees And Offering Expenses		$ 2,600,000
Common stock, shares issued			43,042,548	47,215,116
Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Shares of common stock			4,006,966
Common stock, shares issued			47,215,116
Sale of Stock, Price Per Share		$ 3.265
Warrant [Member]
Summary Of Significant Accounting Policies [Line Items]
Common stock, shares issued		1,531,440
Sale of Stock, Price Per Share		$ 3.2649
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 3.93	$ 3.93
Purchase of Additional Shares Of Common Stock		9,188,406
Pre-Funded Warrants [Member]
Summary Of Significant Accounting Policies [Line Items]
Pre Funded Warrants	1,531,440
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.0001		$ 3.93
Private Placement [Member] \| Common Stock [Member] \| Investor [Member]
Summary Of Significant Accounting Policies [Line Items]
Common stock, shares issued		7,656,966
Private Placement [Member] \| Warrant [Member]
Summary Of Significant Accounting Policies [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 3.9299
Trademarks
Summary Of Significant Accounting Policies [Line Items]
Amortization related to trademark			$ 11,000	$ 11,000
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease, right-of-use asset			6,323,000	9,203,000
Laboratory Equipment
Summary Of Significant Accounting Policies [Line Items]
Disposals of property and equipment			41,000	43,000,000
Disposal of Gross Assets			1,289,000
Gain (loss) on disposal of property and equipment			(157,000)	4,000,000
Cash collected from sale of assets			2,000	6,200,000
General and Administrative Expense
Summary Of Significant Accounting Policies [Line Items]
Patent expenses			2,473,000	2,142,000
Certificate of Deposit
Summary Of Significant Accounting Policies [Line Items]
Short-term restricted cash			150,000,000	$ 150,000,000
Sales Agreement October 2021 \| Transaction Expense
Summary Of Significant Accounting Policies [Line Items]
Proceeds From Sale Of Common Stock Net Commission Paid			$ 37,000,000
Sale of Stock, Number of Shares Issued in Transaction			7,600,373
Jefferies LLC \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Proceeds from Issuance Initial Public Offering			$ 80,000,000
Jefferies LLC \| Transaction Expense
Summary Of Significant Accounting Policies [Line Items]
Proceeds From Sale Of Common Stock Net Commission Paid			$ 80,000,000
Jefferies LLC \| Sales Agreement October 2021 \| Transaction Expense
Summary Of Significant Accounting Policies [Line Items]
Shares of common stock			4,006,966
Proceeds From Sale Of Common Stock Net Commission Paid			$ 13,400,000

Accrued Expenses

12 Months Ended

Dec. 31, 2023

Accrued Liabilities, Current [Abstract]

Accrued Expenses

7. Accrued Expenses

Accrued expenses as of December 31, 2023 and 2022 is summarized as follows:


	December 31,
(In thousands)	2023		2022
Employee and board compensation	$	2,219	$	2,273
Contract research services		1,411		1,038
Professional services		344		243
Contract manufacturing services		163		—
Total	$	4,137	$	3,554