0001564590-21-011777 | 10-K | XBRL Viewer

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2020	Mar. 01, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
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	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		30,457,250
Entity Public Float			$ 695.1
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	21 Erie Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
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, 2020. Portions of such proxy statement are incorporated by reference into Part III of this Form 10-K.

CONSOLIDATED BALANCE SHEETS - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 74,866,133	$ 44,290,030
Marketable securities	10,002,550	15,119,925
Accounts receivable	1,417,482	754,898
Prepaid expenses and other current assets	1,241,239	860,107
Total current assets	87,527,404	61,024,960
Property and equipment, net	2,108,024	1,846,922
Operating lease right-of-use	6,774,229	5,337,026
Deposits	2,572,476	2,572,476
Restricted cash	150,000	150,000
Other long term assets	401,667	673,625
Total assets	99,533,800	71,605,009
Current liabilities:
Accounts payable	2,070,303	882,666
Accrued expenses	2,787,211	2,227,352
Research and development contract liability, current portion	6,681,025	4,097,443
Operating lease liability, current portion	4,777,427	4,447,787
Total current liabilities	16,315,966	11,655,248
Research and development contract liability, net of current portion	1,937,575	4,017,894
Operating lease liability, net of current portion	2,368,787	1,347,971
Total liabilities	20,622,328	17,021,113
Commitments and contingencies (NOTE 14)
Stockholders’ equity:
Preferred stock, $0.001 par value, authorized – 10,000,000 shares; issued and outstanding – none
Common stock, $0.001 par value; authorized – 100,000,000 shares; issued and outstanding – 30,351,366 shares and 26,562,178 shares at December 31, 2020 and 2019, respectively	30,351	26,562
Additional paid in capital	232,159,029	163,067,773
Accumulated other comprehensive income (loss)	7,131	(10,321)
Accumulated deficit	(153,285,039)	(108,500,118)
Total stockholders’ equity	78,911,472	54,583,896
Total liabilities and stockholders’ equity	$ 99,533,800	$ 71,605,009

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
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	30,351,366	26,562,178
Common stock, shares outstanding	30,351,366	26,562,178

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Collaboration revenue	$ 3,154,325	$ 3,458,331
Operating expenses:
General and administrative	14,651,205	12,740,093
Research and development	33,545,705	27,487,485
Total operating expenses	48,196,910	40,227,578
Loss from operations	(45,042,585)	(36,769,247)
Other income:
Interest income, net	463,914	482,790
Total other income	463,914	482,790
Loss before provision for income taxes	(44,578,671)	(36,286,457)
Provision for income taxes	(206,250)	(412,500)
Net loss	(44,784,921)	(36,698,957)
Unrealized gains from available-for-sale securities	17,452	637
Comprehensive loss	$ (44,767,469)	$ (36,698,320)
Net loss per common share – basic and diluted	$ (1.56)	$ (1.66)
Weighted average common shares outstanding – basic and diluted	28,688,625	22,041,792

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($)	Total	Common Stock	Additional Paid-in Capital	AOCI Attributable to Parent	Accumulated Deficit
Balance at Dec. 31, 2018	$ 33,971,469	$ 20,697	$ 105,762,891	$ (10,958)	$ (71,801,161)
Balance, Shares at Dec. 31, 2018		20,697,453
Issuance of common stock from public offerings, net of underwriter commissions and fees	48,998,907	$ 5,314	48,993,593
Issuance of common stock from public offerings, net of underwriter discounts, Shares		5,314,055
Stock-based compensation	6,520,982		6,520,982
Exercise of stock options	$ 1,881,873	$ 485	1,881,388
Exercise of stock options, Shares	485,105	485,105
Issuance of common stock upon cashless exercise of warrants, net of shares withheld		$ 45	(45)
Issuance of common stock upon exercise of warrants, net, Shares		44,319
Restricted stock awards	$ 12	$ 33	(21)
Restricted stock awards, Shares		33,333
Repurchase of restricted stock awards	(91,027)	$ (12)	(91,015)
Repurchase of restricted stock awards, Shares		(12,087)
Unrealized gains from available-for-sale securities	637			637
Net loss	(36,698,957)				(36,698,957)
Balance at Dec. 31, 2019	54,583,896	$ 26,562	163,067,773	(10,321)	(108,500,118)
Balance, Shares at Dec. 31, 2019		26,562,178
Issuance of common stock from public offerings, net of underwriter commissions and fees	56,682,236	$ 3,017	56,679,219
Issuance of common stock from public offerings, net of underwriter discounts, Shares		3,016,901
Stock-based compensation	10,480,782		10,480,782
Exercise of stock options	$ 2,203,061	$ 454	2,202,607
Exercise of stock options, Shares	454,497	454,497
Issuance of common stock upon cashless exercise of warrants, net of shares withheld		$ 278	(278)
Issuance of common stock upon exercise of warrants, net, Shares		278,179
Restricted stock awards	$ 17	$ 57	(40)
Restricted stock awards, Shares		56,665
Repurchase of restricted stock awards	(271,051)	$ (17)	(271,034)
Repurchase of restricted stock awards, Shares		(17,054)
Unrealized gains from available-for-sale securities	17,452			17,452
Net loss	(44,784,921)				(44,784,921)
Balance at Dec. 31, 2020	$ 78,911,472	$ 30,351	$ 232,159,029	$ 7,131	$ (153,285,039)
Balance, Shares at Dec. 31, 2020		30,351,366

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (44,784,921)	$ (36,698,957)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,057,458	810,782
Stock-based compensation	10,480,782	6,520,982
Loss on disposal of fixed asset		54,274
Other non cash charges	(563,232)
Amortization of premium/discount on purchased securities	83,694	(72,464)
Changes in operating assets and liabilities:
Account receivable	(662,584)	(754,898)
Prepaid expenses and other current assets	(381,132)	487,182
Operating lease right-of-use asset	(4,202,480)	4,354,810
Other assets	(4,971)	123,437
Deposits		(1,559,704)
Accounts payable	741,265	(1,152,688)
Accrued expenses	559,859	439,290
Research and development contract liability	503,263	928,588
Operating lease liability	4,678,965	(4,277,544)
Net cash used in operating activities	(32,494,034)	(30,796,910)
Cash flows from investing activities:
Purchases of property and equipment	(595,259)	(46,353)
Redemption of short term investments	15,000,000	18,500,000
Purchases of marketable securities	(9,948,867)	(15,134,324)
Cash received from sale of fixed asset		127,500
Net cash provided by investing activities	4,455,874	3,446,823
Cash flows from financing activities:
Proceeds from the public offering of common stock, net of underwriter's commission and fees	56,682,236	48,998,907
Restricted stock repurchase at vesting to cover taxes	(271,051)	(91,027)
Proceeds from the exercise of stock options	2,203,061	1,881,873
Net cash provided by financing activities	58,614,263	50,789,765
Net increase in cash, cash equivalents, and restricted cash	30,576,103	23,439,678
Cash, cash equivalents, and restricted cash at beginning of year	44,440,030	21,000,352
Cash, cash equivalents, and restricted cash at end of year	75,016,133	44,440,030
Supplemental disclosures of cash flow information:
Income taxes		412,500
Purchases of property and equipment in accounts payable or accrued expenses	446,372
Operating lease modification	5,639,000
Restricted Stock
Cash flows from financing activities:
Issuance of restricted stock awards	$ 17,000	$ 12,000

Organization and Basis of Presentation

12 Months Ended

Dec. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Basis of Presentation

1.	Organization and Basis of Presentation

Cue Biopharma, Inc. (the “Company”) was incorporated in the State of Delaware on December 31, 2014 under the name Imagen Biopharma, Inc., and completed its organization, formation and initial capitalization activities effective as of January 1, 2015. In October 2016, the Company changed its name to Cue Biopharma, Inc. The Company’s corporate office and research facilities are located in Cambridge, Massachusetts.

The Company is a clinical-stage biopharmaceutical company engineering a novel class of injectable biologics to selectively engage and modulate targeted T cells within the patient’s body to treat a broad range of cancers, chronic infectious diseases, and autoimmune disorders.

The Company is in the development stage and has incurred recurring losses and negative cash flows from operations. As of December 31, 2020, the Company had unrestricted cash, cash equivalents and marketable securities of approximately $84.9 million. Management believes that current cash, cash equivalents and marketable securities on hand at December 31, 2020 are sufficient to fund operations for at least the next twelve months from the date of issuance of these financial statements; however, the future viability of the Company is dependent on its ability to raise additional capital to finance its operations and to fund increased research and development costs in order to seek approval for commercialization of its drug product candidates. 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 the Company’s drug product candidates in order to generate future revenue streams.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements for the years ended December 31, 2020 and 2019, 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 Corporation, Inc., 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 June 2019, the Company entered into an “at-the-market” (“ATM”) equity offering sales agreement (the “June 2019 ATM Agreement”) with Stifel Nicolaus & Company, Inc. (“Stifel”) to sell shares of the Company’s common stock for aggregate gross proceeds of up to $30 million, from time to time, through an ATM equity offering program under which Stifel acted as sales agent. As of December 31, 2020, the Company had sold 3,584,945 shares of common stock under the June 2019 ATM Agreement for proceeds of approximately $29.4 million, net of commissions paid, but excluding transaction expenses, and terminated this equity offering upon completion.

In November 2019, the Company entered into an ATM equity offering sales agreement with Stifel (the “November 2019 ATM Agreement”) to sell shares of the Company’s common stock for aggregate gross proceeds of up to $20 million, from time to time, through an ATM equity offering program under which Stifel acted as sales agent. As of December 31, 2020, the Company had sold 1,729,110 common shares under the November 2019 ATM Agreement for proceeds of approximately $19.6 million, net of commissions paid, but excluding estimated transaction expenses, and terminated this equity offering upon completion.

In March 2020, the Company entered into an ATM equity offering sales agreement with Stifel (the “March 2020 ATM Agreement”) to sell shares of the Company’s common stock for aggregate gross proceeds of up to $35 million, from time to time, through an ATM equity offering program under which Stifel would act as sales agent. As of December 31, 2020, the Company had sold a total of 1,824,901 shares of common stock under the March 2020 ATM Agreement for proceeds of approximately $34.3 million, net of commissions paid, but excluding estimated transaction expenses. Due to the issuance and sale of all the shares of common stock subject thereto, the March 2020 ATM Agreement terminated in accordance with its terms.

In June 2020, the Company entered into an ATM equity offering sales agreement with Stifel (the “June 2020 ATM Agreement”) to sell shares of the Company’s common stock for aggregate gross proceeds of up to $40 million, from time to time, through an ATM equity offering program under which Stifel acts as sales agent. The June 2020 ATM Agreement will terminate upon the earliest of (a) the sale of $40 million of shares of the Company’s common stock or (b) the termination of the June 2020 ATM Agreement by the Company or Stifel. As of December 31, 2020, the Company had sold 1,192,000 shares of common stock under the June 2020 ATM Agreement for proceeds of approximately $22.4 million, net of commissions paid, but excluding estimated transaction expenses.

Consolidation

The accompanying consolidated financial statements include the Company and its wholly owned subsidiary, Cue Biopharma Securities Corporation, Inc. The Company has eliminated all intercompany transactions for the years presented.

Reclassifications

Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations.

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

Cash and Cash Equivalents

The Company considers all 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 are recognized and are included in other comprehensive income (loss). Realized gains are recognized and determined on a specific identification basis and are included in other income (loss) on the income statement. Amortization and accretion of discounts and premiums is recorded in interest income. The Company currently invests in United States Treasury obligations.

Restricted Cash

The Company purchased a $150,000 certificate of deposit to collateralize a credit card account with a commercial bank that was classified as short-term certificate of deposit as of December 31, 2020.

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 disposition 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 in and 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.

As the Company can renew the underlying rights to the CUE BIOLOGICS Mark indefinitely at nominal cost, this acquired intangible asset has been classified as a component of other long term assets, having a useful life of 15 years. The Company recorded $11,666 and $11,667 in amortization related to the trademark at December 31, 2020 and 2019, respectively.

Revenue Recognition

The Company follows the provisions of Accounting Standards Codification 606, Revenue from Contracts with Customers (“ASC 606”). The Company generates revenue solely through collaboration arrangements with strategic partners for the development and commercialization of drug product candidates. The core principle of ASC 606 is that an entity should recognize revenue to depict the transfer of promised goods and/or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and/or services. To determine the appropriate amount of revenue to be recognized for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following steps: (i) Identify the contract(s) with the customer, (ii) Identify the performance obligations in the contract, (iii) Determine the transaction price, (iv) Allocate the transaction price to the performance obligations in the contract and (v) Recognize revenue when (or as) each performance obligation is satisfied.

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 judgement 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 “most likely amount” 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 most likely amount method. Currently, the Company has one contract with an option to acquire additional goods and/or services in the form of additional research and development services for additional drug product candidates which it evaluated and determined that it was not a material right related to the LG Chem agreement.

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 operations as incurred. For the years ended December 31, 2020 and 2019, patent expenses were $1,879,000 and $1,934,000, respectively. Patent expenses are included in general and administrative expenses in the Company’s consolidated statements of operations and comprehensive loss.

Licensing Fees and Costs

Licensing fees and costs consist primarily of costs relating to the acquisition of the Company’s license agreement with Einstein, including related royalties, maintenance fees, milestone payments and product development costs. Licensing fees and costs are charged to operations as incurred.

Long-Lived Assets

The Company reviews long-lived assets, consisting of property and equipment and a trademark, for impairment at each fiscal year end or 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, 2019, the Company sold lab equipment with a net book value of approximately $181,000 that was being decommissioned and recognized a loss of approximately $54,000. There were no sales of lab equipment or capital equipment during the year ended December 31, 2020.

Leases

In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-02, Leases (ASC 842) (“ASU-2016-02”), which supersedes the existing guidance for lease accounting, Leases (ASC 840). ASU 2016-02 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 to assess the amount, timing and uncertainty of cash flows arising from leases are required. The standard is effective for fiscal years beginning after December 15, 2018.

The adoption of ASC 842 on January 1, 2019 resulted in the recognition of approximately $9,692,000 of right-of-use asset and $9,347,000 of lease liabilities on the Company’s balance sheet. The adoption did not have a material net impact on the Company’s consolidated statements of operations or accumulated deficit. Please refer to Note 14 for more detail.

Stock-Based Compensation

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

Stock-based payments to officers, directors, members of the Company’s Scientific and Clinical Advisory Board, non-employees and outside consultants and employees, 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 volatilities 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 the Company’s 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 statements of operations, 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.

The Company recognized approximately, $206,250 and $412,500 of income tax expense related to the foreign taxes withheld from an upfront payment received from LG Chem, Ltd. (“LG Chem”) pursuant to a collaboration agreement with LG Chem (the “LG Chem Agreement”) during the year ended December 31, 2020 and 2019, respectively.

The Company recognizes interest accrued relative to unrecognized tax benefits in interest expense and penalties in operating expense. During the years ended December 31, 2020 and 2019, 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, 2020 and 2019.

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 loss includes net loss as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive loss in all periods presented, other than its net loss, was unrealized gains and losses 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.

At December 31, 2020 and 2019, the Company excluded the outstanding securities summarized below, which entitle the holders thereof to acquire shares of common stock, from its calculation of earnings per share, as their effect would have been anti-dilutive.

	December 31,
	2020		2019
Common stock warrants		861,969		1,189,827
Common stock options		5,030,899		4,793,253
Nonvested restricted stock units		230,002		66,667
Total		6,122,870		6,049,747

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.

Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company has determined that its financial assets are currently classified within Level 1 and that its financial liabilities are currently all classified within Level 3 in the fair value hierarchy. In determining the appropriate levels, the Company performs an analysis of the assets and liabilities at each reporting period end.

The Company had $72,943,275 in cash equivalents and $10,002,550 in short-term marketable securities that were measured and recorded at fair value on the Company’s balance sheet at December 31, 2020. The Company had $39,303,609 in cash equivalents and $15,119,925 in short-term marketable securities that were measured and recorded at fair value on the Company’s balance sheet at December 31, 2019.

The carrying value of financial instruments (consisting of cash, a certificate of deposit, 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 ASU No. 2016-13, Financial Instruments- Credit Losses: Measurement of Credit Losses on Financial Instruments (ASC 326) (CECL). The 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 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 is still evaluating the impact of ASU 2016-13 on the Company’s consolidated financial statements, if any.

In December 2019, the FASB issued ASU No. 2019-12, “Income Taxes (ASC 740): Simplifying the Accounting for Income Taxes,” which is intended to simplify various aspects related to accounting for income taxes. The pronouncement is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. ASU No. 2019-12 is effective for us beginning in the fiscal year ending December 31, 2021. The Company is currently in the process of evaluating the effects of this pronouncement on the 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.

Fair Value

12 Months Ended

Dec. 31, 2020

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 generally accepted accounting principles 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, 2020 and 2019 and indicate the level of the fair value hierarchy utilized to determine such fair value:

	Fair Value Measurements as of December 31, 2020
	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	72,943,275	$	—	$	—	$	72,943,275
Marketable securities		—		10,002,550		—		10,002,550
Total	$	72,943,275	$	10,002,550	$	—	$	82,945,825

	Fair Value Measurements as of December 31, 2019
	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	39,303,609	$	—	$	—	$	39,303,609
Marketable securities		—		15,119,925		—		15,119,925
Total	$	39,303,609	$	15,119,925	$	—	$	54,423,534

As of December 31, 2020 and 2019, the Company’s cash equivalents that are invested in money market funds valued using Level 1 inputs for identical securities. The Company measures the fair value of marketable securities that are invested in United States Treasury securities using Level 2 inputs and primarily relies on quoted prices in active markets for similar marketable securities. During the year ended December 31, 2020 and 2019, 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

Marketable Securities

12 Months Ended

Dec. 31, 2020

Investments Debt And Equity Securities [Abstract]

Marketable Securities

4.	Marketable Securities

As of December 31, 2020 and 2019, the fair value of available-for-sale marketable securities by type of security was as follows:

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury Securities	$	9,995,419	$	7,131	$	—		$	10,002,550
	$	9,995,419	$	7,131	$	—		$	10,002,550

	December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury Securities	$	15,130,246	$	—	$	(10,321	)	$	15,119,925
	$	15,130,246	$	—	$	(10,321	)	$	15,119,925

At December 31, 2020, marketable securities consisted of $10,002,550 of investments that mature within twelve months. The Company recorded an unrealized gain on investments of $17,452 for the year ended December 31, 2020. At December 31, 2019, the Company marketable securities consisted of $15,119,925 of investments that mature within twelve months. The Company recognized an unrealized gain on investments of $637 for the year ended December 31, 2019.

Property and Equipment

12 Months Ended

Dec. 31, 2020

Property Plant And Equipment [Abstract]

Property and Equipment

5.	Property and Equipment

Property and equipment as of December 31, 2020 and 2019 is summarized as follows:

	December 31,
	2020			2019
Laboratory equipment	$	4,148,426		$	3,587,559
Furniture and fixtures		93,321			93,321
Computer equipment		267,837			192,092
Construction in progress		405,019			—
		4,914,603			3,872,972
Less accumulated depreciation		(2,806,579	)		(2,026,050	)
Net property and equipment	$	2,108,024		$	1,846,922

Depreciation expense for the year ended December 31, 2020 was included in the consolidated statements of operations and comprehensive loss as follows, excluding trademark amortization of $11,666 and amortization of capitalized license expenses of $265,263. Depreciation expense for the year ended December 31, 2019 was included in the consolidated statements of operations and comprehensive loss as follows, excluding trademark amortization of $11,667.

	Years Ended December 31,
	2020		2019
General and administrative	$	20,301	$	60,974
Research and development		760,228		738,140
Total	$	780,529	$	799,114

During the year ended December 31, 2019, the Company sold lab equipment with an acquisition cost of $320,778 and accumulated depreciation of $139,003, and realized a loss of $54,274. The Company did not sell lab equipment or other capital equipment during the year ended December 31, 2020.

Accrued Expenses

12 Months Ended

Dec. 31, 2020

Accrued Liabilities Current [Abstract]

Accrued Expenses

6.	Accrued Expenses

Accrued expenses as of December 31, 2020 and 2019 is summarized as follows:

	December 31,
	2020		2019
Accrued compensation	$	1,963,983	$	1,575,821
Contract manufacturing services		108,880		150,250
Professional Services		326,028		383,910
Contract research services		388,320		117,371
	$	2,787,211	$	2,227,352

Einstein License and Service Agreement

12 Months Ended

Dec. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Einstein License and Service Agreement

7.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 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 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, 2020, $150,000 had been paid by the Company towards 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, 2020 and 2019.

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 the costs incurred in connection with the Einstein License in accordance with ASC 730, Research and Development. For the years ended December 31, 2020 and 2019, costs aggregated $75,000 and $565,659, respectively resulting from LG milestone payments earned with respect to the Einstein License. For the years ended December 31, 2020 and 2019, $75,000 and $50,000 were included in research and development expenses in the consolidated statements of operations and comprehensive loss. As of December 31, 2020, the Company capitalized $416,855 net of amortization with respect to the Einstein License pursuant to ASC 606 and ASC 340-40, Other Assets and Deferred Costs: Contracts with Customers in prepaid expenses and other current assets. As of December 31, 2019, the Company capitalized $525,554 with respect to the Einstein License pursuant to ASC 606 and ASC 340. The Company recorded $265,262 and $260,292 in prepaid expenses and other current assets and other long term assets, respectively.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

8.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 provide 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, 2020, the Company granted stock options to purchase 981,800 shares of the Company’s common stock and 220,000 restricted stock units. At December 31, 2020, stock options for 4,459,301 shares of common stock and 320,000 restricted stock units had been granted and 750,325 shares of common stock were reserved for future grants under the Omnibus Plan, and stock options for 481,600 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, 2020, stock options for a total of 4,940,901 shares of common stock and 320,000 restricted stock units had been granted and 755,725 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

For stock options requiring an assessment of value during the years ended December 31, 2020 and 2019, the fair value of each stock option award was estimated using the Black-Scholes option-pricing model utilizing the following assumptions:

	December 31,
	2020	2019
Risk-free interest rate	0.38 to 1.56%	1.75 to 2.58%
Expected dividend yield	0%	0%
Expected volatility	93.4-99.6%	88.0-94.0%
Expected life	5.5 to 6.25 years	4.0 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, 2020 is as follows:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in Years)
Stock options outstanding at December 31, 2018		4,540,321		$	7.08		5.16
Granted		1,288,100
Exercised		(485,105	)
Cancelled		(550,063	)
Stock options outstanding at December 31, 2019		4,793,253		$	7.10		5.64
Granted		981,800			17.31
Exercised		(454,497	)		4.86
Cancelled		(289,657	)		10.14
Stock options outstanding at December 31, 2020		5,030,899		$	9.10		5.51
Stock options exercisable at December 31, 2020		2,920,318		$	7.05		4.03

The Company recognized, $8,861,760 and $6,208,949, in stock-based compensation during the years ended December 31, 2020 and 2019, respectively related to stock option activity. As of December 31, 2020, total unrecognized stock-based compensation was approximately $15,605,021, which is expected to be recognized as an operating expense in the Company’s consolidated statements of operations and comprehensive loss through June 2022.

The aggregate intrinsic value of exercisable but unexercised in-the-money stock options at December 31, 2020 was approximately $16,869,399 based on a weighted average exercise price of $7.05 per share. The aggregate intrinsic value of options is calculated as the difference of the market close price of $12.51 on December 31, 2020, and the weighted average exercise price of $7.05, with a weighted average remaining contractual term of 4.03 years.

The aggregate intrinsic value of exercisable but unexercised in-the-money stock options at December 31, 2019 was approximately $19,471,155, based on a weighted average exercise price of $6.26 per share at December 31, 2019.

Option Amendments- Modification of Incentive Stock Options

During the year ended December 31, 2020, the following event resulted in the amendment to terms of outstanding stock option awards:

On January 22, 2020, an employee who was employed for a particular role pursuant to an employment agreement that prescribed certain separation benefits to the employee was separated from that role. Per the employment agreement, upon termination (i) all unvested stock options would accelerate and become vested as of the termination date, and (ii) the options would remain exercisable, to the extent applicable, following the date of termination for the period prescribed in the equity award plan. As of January 21, 2020, the terminated employee held outstanding options to purchase an aggregate of 215,000 shares of the Company's common stock at a weighted average exercise price of $6.22 per share, including unvested options to purchase 94,375 shares at a weighted average exercise price of $7.83 per share. On January 21, 2020, the unvested portion of the outstanding options vested, and the post-employment option exercise period was extended from 90 days, as prescribed to the equity award plan, to 12 months from the date of the termination. In May 2020, the final separation agreement was amended to extend the post-employment option exercise period from 12 months to 36 months.

The Company calculated the change in stock-based compensation cost associated with the previously described stock option modifications pursuant to the applicable guidance in ASC 718. The change in compensation cost was determined by calculating the difference between (a) the estimated fair value of each option award immediately prior to the modifications and (b) the estimated fair value of each option award immediately after the modifications. The fair value of each option award immediately prior to and immediately after modification was estimated using the Black-Scholes option-pricing model to determine an incremental fair value, consistent with and in accordance with the Company’s existing accounting policy for stock compensation. The total additional compensation cost associated with the previously described modifications was determined to be approximately $344,850, which was expensed in the year ended December 31, 2020.

Restricted Stock Units

On October 3, 2019, the Company granted 100,000 restricted stock units (“RSUs”) with time-based vesting conditions to certain executives. During the year ended December 31, 2019, the Company awarded 100,000 RSUs at an average grant date fair value of $7.53 per share. The RSUs vest in three substantially equal installments beginning on grant date, and annually 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 vest on September 30, 2021, and the balance vest on March 31, 2022, subject to the recipient’s continued service on each applicable vesting date. On March 31, 2020, the Company granted 50,000 RSUs with time-based vesting conditions to an executive officer. The RSUs vest in three substantially equal installments beginning on the grant date, and annually thereafter, subject to the recipient’s continued service on each applicable vesting date. 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 substantially equal installments beginning on the grant date, and annually thereafter, subject to the recipient’s continued service on each applicable vesting date. Compensation expense is recognized on a straight-line basis.

The following table summarizes the RSU activity for the under the Omnibus Plan for the year ending December 31, 2020:

Restricted Securities	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance as of December 31, 2019		66,667		$	7.53
Granted		220,000			17.96
Vested/Released		(56,665	)		10.94
Forfeited		—			—
Nonvested balance at December 31, 2020		230,002		$	16.66

The Company recognized $1,619,022 and $312,032 in stock-based compensation during the years ended December 31, 2020 and 2019, respectively, related to restricted stock unit activity. As of December 31, 2020, total unrecognized stock-based compensation was approximately $2,772,845, which is expected to be recognized as an operating expense in the Company’s consolidated statements of operations and comprehensive loss through June 2022.

Stock-based Compensation

Stock-based compensation for the years ended December 31, 2020 and 2019 was included in the consolidated statements of operations and comprehensive loss as follows:

	December 31,
	2020		2019
General and administrative	$	4,093,542	$	2,109,335
Research and development		6,387,240		4,411,647
Total	$	10,480,782	$	6,520,982

Warrants

12 Months Ended

Dec. 31, 2020

Warrants And Rights Note Disclosure [Abstract]

Warrants

The Company has two tranches of common stock warrants outstanding at December 31, 2020. The first tranche was exercisable for 370,370 shares of common stock issued on June 15, 2015 with an exercise price of $2.70 per share. These warrants were issued with a 7 year term and expire on June 15, 2022. The second tranche was exercisable for 882,071 shares of common stock issued on December 27, 2017 with an exercise price of $9.38 per share. These warrants were issued with a 5 year term and expire on December 26, 2022. The intrinsic value of exercisable but unexercised in-the-money common stock warrants at December 31, 2020 was approximately $3,187,000 based on a fair value of $12.51 per share on December 31, 2020.

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 following table summarizes common stock warrant activity for the year ended December 31, 2020:

	Warrant Issued June 15, 2015 Tranche 1			Warrant Issued December 27, 2017 Tranche 2			Total
Balance at December 31, 2019		322,259			867,568			1,189,827
Issued via cashless exercises		(227,184	)		(50,995	)		(278,179	)
Withheld as payment to cover issued shares		(22,464	)		(27,215	)		(49,679	)
Balance at December 31, 2020		72,611			789,358			861,969

Revenue Recognition

12 Months Ended

Dec. 31, 2020

Revenue From Contract With Customer [Abstract]

Revenue Recognition

10.	Revenue Recognition

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, (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 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 “most likely amount” 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 judgement 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 the 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.

On November 14, 2017, the Company entered into a collaboration agreement (the “Merck Agreement”) with Merck Sharp & Dohme Corp. (“Merck”) for a partnership to research and develop certain of the Company’s proprietary biologics that target certain autoimmune disease indications (the “Initial Indications”). The Company views the Merck Agreement as a component of its development strategy since it will allow the Company to advance its autoimmune programs in partnership with a world class pharmaceutical company, while also continuing its focus on its more advanced cancer programs. The research program outlined in the Merck Agreement entails (1) the Company’s research, discovery and development of certain Immuno-STAT^TM drug candidates up to the point of demonstration of certain biologically relevant effects (“Proof of Mechanism”) and (2) the further development by Merck of the Immuno-STAT drug candidates that have demonstrated Proof of Mechanism (the “Proposed Drug Product Candidates”) up to the point of demonstration of all or substantially all of the properties outlined in such Proposed Drug Product Candidates’ profiles as described in the Merck Agreement.

In exchange for the licenses and other rights granted to Merck under the Merck Agreement, Merck paid to the Company a $2.5 million nonrefundable up-front payment. Additionally, the Company may be eligible to receive funding in developmental milestone payments, as well as tiered royalties, if all research, development, regulatory and commercial milestones agreed upon by both parties are successfully achieved. Excluding the up-front payment described above, the Company is eligible to earn up to $101 million for the achievement of certain research and development milestones, $120 million for the achievement of certain regulatory milestones and $150 million for the achievement of certain commercial milestones, in addition to tiered royalties on sales, if all pre-specified milestones associated with multiple products across the primary disease indication areas are achieved. The Merck Agreement requires the Company to use the first $2.5 million milestone payment it receives under the agreement to fund contract research. The amount of the royalty payments is a percentage of product sales ranging in the single digits based on the amount of such sales.

As it relates to the Merck Agreement, the Company recognized the upfront payment associated with its one open contract 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. Amounts expected to be recognized as revenue within the twelve months following the balance sheet date are classified in current liabilities. Amounts not expected to be recognized as revenue within the twelve months following the balance sheet date are classified as contract liabilities, net of current portion. The Company determined that there was one performance obligation: consisting of the license and research development services. Thus, the transaction price of $2.5 million was allocated to the single performance obligation.

On November 18, 2020, the Company entered into a First Amendment to the Merck Agreement (the “Amendment”) with Merck. Pursuant to rights granted to Merck under the Merck Agreement, the Amendment extends the term of the research program under the Merck Agreement for an additional year, until December 31, 2021. Under the terms of the Amendment, Merck will reimburse the Company for specified expenses and provide additional financial research support to further study and develop preclinical biologics with the objective of identifying clinical candidates subject, in each case, to specified maximum amounts, with any amounts in excess of such maximum amounts to be borne by the Company. On November 18, 2020, the Company earned a milestone payment related to this Amendment in the amount of $300,000. The $300,000 milestone payment was recorded as a contract liability upon receipt. The Company will recognize revenue related to this milestone payment pursuant to its revenue recognition policy in relation to the performance of its obligations related to the development of Immuno-STAT drug candidates under the arrangement.

Aside from the $300,000 milestone payment earned to date, the Company does not believe that any variable consideration should be included in the transaction price at December 31, 2020. 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 by assessing the effort and expense expended during the period. For the year ended December 31, 2020, the Company recognized approximately $177,000 in collaboration revenue related to this agreement and recorded short and long-term research and development liabilities on its balance sheet dated December 31, 2020 of $606,771 and $0, respectively. For the year ended December 31, 2019, the Company recognized approximately $874,000 in collaboration revenue related to this agreement and recorded short and long-term research and development liabilities on its balance sheet dated December 31, 2019 of $483,515 and $0, respectively.

On November 6, 2018, the Company entered into the LG Chem Agreement with LG Chem related to the development of the Company’s Immuno-STATs focused in the field of oncology. Pursuant to the LG Chem 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 (the “LG Chem Territory”). Pursuant to a global license and collaboration agreement, dated December 18, 2019, as amended on November 5, 2020, LG Chem has the option to elect one additional Immuno-STAT for an oncology target on or prior to April 30, 2021 for a worldwide development and commercialization license, and the Company will retain an option to co-develop and co-commercialize the additional program worldwide. The Company retains rights to develop and commercialize all assets included in the agreement in the United States and in global markets outside of Asia. In exchange for the licenses and other rights granted to LG Chem under the LG Chem Agreement, LG Chem made a $5.0 million equity investment in common stock of the Company and a $5.0 million nonrefundable upfront cash payment. The Company is also eligible to receive up to an additional $400 million in research, development, regulatory and sales milestones. In addition, the LG Chem 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 FDA acceptance of the IND for the Company’s lead drug candidate, CUE-101, pursuant to the LG Chem 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 statements of operations and 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 Agreement. The $1.25 million milestone payment was recorded as a contract liability upon receipt. Revenue related to this milestone payment will be 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 comprehensive loss.

The Company recorded short and long-term research and development liabilities on its balance sheet dated of $6,074,254 and $1,937,575, respectively, for the year ended December 31, 2020.

Aside from the $3.75 million 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, 2020. 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, 2020 and 2019, the Company recognized revenue of approximately $2,978,000 and $2,584,000, respectively, related to the LG Chem Agreement.

The Company considered the capitalization of contract costs under the guidance in ASC 340. There were no contract costs identified in the Merck Agreement. As it related to the LG Chem Agreement, the Company capitalized license expenses of approximately $907,600 as of December 31, 2020, pursuant to the Einstein License 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 upfront 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 $156,600 in capitalized license expenses related to the milestone payment received in December 2020, net of accumulated amortization of approximately $490,700. For the year ended December 31, 2020, approximately $416,900 was included in prepaid expenses and other short-term assets and $0 is included in other long-term assets.

- 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

+ Details

Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Stockholders Equity [Abstract]

Stockholders' Equity

11.	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, 2020 and 2019. 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 30,351,366 shares and 26,562,178 shares were issued and outstanding at December 31, 2020 and 2019, respectively.

Related Party Transactions

12 Months Ended

Dec. 31, 2020

Related Party Transactions

12.	Related Party Transactions

Information with respect to payments under the Einstein License is described in Note 7.

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

13.	Income Taxes

The Company accounts for income taxes under the provision of ASC 740, Income Taxes. The Company reported a $206,250 tax provision for the year ended December 31, 2020 related to foreign withholding taxes paid.

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, 2020 and 2019 are as follows:

	2020			2019
Deferred tax assets:
Net operating loss carryforwards	$	34,539,000		$	23,348,000
Research and other credits		2,312,000			2,069,000
Reserves and accruals		7,446,000			5,281,000
Other		—			3,000
Total gross deferred tax assets		44,297,000			30,701,000
Less valuation allowance		(42,321,000	)		(29,095,000	)
Total deferred tax assets		1,976,000			1,606,000
Deferred tax liability:
Depreciation		(1,974,000	)		(1,606,000	)
Other		(2,000	)		—
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, 2020, and 2019, 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, 2020, 2019, and 2018, 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, 2020, 2019, and 2018 is as follows:

	Years Ended December 31,
	2020			2019
U. S. Federal statutory tax rate		(21	)%		(21	)%
State Taxes		(7	)%		(6	)%
Change in valuation allowance		30	%		27	%
Tax credits		(1	)%		(2	)%
Stock based compensation		(2	)%		1	%
Tax reform		0	%		0	%
Foreign withholding taxes		0	%		1	%
Other		1	%		1	%
Effective tax rate		0	%		1	%

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, 2020 and 2019, the Company had unrecognized tax benefits related to Federal and state research tax credits of approximately $1,675,000 and $1,334,000, 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, 2020, the Company has available net operating loss carryforwards for Federal and state income tax purposes of approximately $126,941,033 and $126,360,676, respectively, which, if not utilized earlier, will begin to expire in 2035. Approximately, $98,429,255 of the federal net operating losses have an indefinite carryforward. The Company has Federal research credits of approximately $2,993,000, which, if not utilized earlier, will begin to expire in 2035, and state research credits of approximately $1,151,000, which, if not utilized earlier, will begin to expire in 2031. At December 31, 2020 the Company recorded $250,000 in research credits as prepaid to be offset against payroll tax liabilities associated with research and development personnel in 2020 in addition to the approximately $250,000 in research and development credits remaining in prepaid from 2019.

Ownership changes, as defined in the Internal Revenue Code, including those resulting from the issuance of common stock in connection with our public offerings, may limit the amount of net operating loss and tax credit carryforwards that can be utilized to offset future taxable income or tax liability. The amount of the limitation is determined in accordance with Section 382 of the Internal Revenue Code. We have performed an analysis of ownership changes through December 31, 2020. Based on this analysis, we do not believe that any of our tax attributes will expire unutilized due to Section 382 limitations.

The following is a reconciliation of the Company’s gross uncertain tax position at December 31, 2020 and 2019:

	Year Ended December 31,
	2020		2019
Balance at the beginning of year	$	1,334,000	$	972,000
Additions for current year tax provisions		341,000		294,000
Additions for prior year tax provisions		—		81,000
Reductions of prior year tax provisions		—		(13,000	)
Balance as of end of year	$	1,675,000	$	1,334,000

- 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 + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

14.	Commitments and Contingencies

Einstein License and Service Agreement

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 Merck

See discussion of the Merck Agreement in Note 10.

Collaboration Agreement with LG Chem Life Sciences

See discussion of the LG Chem Agreement in Note 10.

Leased Facilities

The Company leases approximately 19,900 square feet of office space in Cambridge, Massachusetts under a lease that began in May 2018 and is scheduled to expire on April 14, 2021 (the “Lease”), as discussed further below. Upon adoption of ASU 2016-02, the Company recorded a right-of-use asset and corresponding lease liability for the Lease on January 1, 2019, by calculating the present value of lease payments, discounted at 6%, the Company’s estimated incremental borrowing rate annually, over the 2.3-year remaining term.

On January 18, 2018, the Company entered into an operating lease agreement for its laboratory and office space in Cambridge, Massachusetts for the period from May 1, 2018 through April 30, 2021 (the “Laboratory and Office Lease”). The lease contains escalating payments during the lease period. Upon execution of this lease agreement the Company prepaid three months of rent, two of which will be held in escrow and credited against future rent payments and that the other of which was applied to the first months’ rent. The Company also prepaid seven and one half months’ rent pursuant to an amendment to the lease agreement executed on June 18, 2018. These amounts were recorded to deposits and prepaid expenses, respectively, at December 31, 2020.

On June 18, 2018, the Company entered into an amendment to the Laboratory and Office Lease that provided the Company with a reduction in rental fees for its office and laboratory space in exchange for prepayment of a portion of the fees. This amendment was effective beginning on May 15, 2018 and expires on April 14, 2021.

The monthly rent payment due under the Laboratory and Office Lease is currently $330,550 until April 2021 and will increase to $375,174 for the remainder of the term.

On September 20, 2018, the Company entered into an operating lease for additional laboratory space at 21 Erie Street, Cambridge, Massachusetts for the period from October 15, 2018 through April 14, 2021(the “Additional Laboratory Lease”). The lease contains escalating payments during the lease period. The monthly rental rate under the Additional Laboratory Lease was $72,600 for the first 12 months and $78,600 for the remainder of the term. Upon execution of this lease agreement the Company prepaid 12 months’ rent pursuant to the lease agreement executed on September 20, 2018.

On September 19, 2019, the Company entered into a second amendment to the Additional Laboratory Lease that removed one holding room from the additional laboratory space. The amendment was effective beginning on October 1, 2019 and expires on April 14, 2021. The monthly rental rate under the Additional Laboratory Lease decreased from $78,600 to $58,995, for the remainder of the lease term. The partial termination of the lease did not change the classification of the lease and remained accounted for as an operating lease. The weighted-average discount rate remained the same at 6%. The Company accounted for the lease modification under ASC 842 that removed one holding room by electing Approach 1, which remeasured the right-of-use asset on the basis of the amount of the liability change. The modification of the partial termination resulted in a reduction to right-of-use asset and lease liability of $335,465 and $327,079, respectively. The difference of $8,386 was recorded as a loss to the right-of-use asset as of December 31, 2019.

On June 24, 2020, the Company entered into a second amendment to the Laboratory and Office Lease. Pursuant to the amendment (1) the term of the lease was extended to June 14, 2022 and (2) the monthly rental rate for the last 14 months of the lease term was increased to $375,174. The Company determined that the amendment should be accounted for as a lease modification applicable under ASC 842, not as a separate contract, with an effective date of lease modification of May 14, 2020. At the effective date of modification, the Company recorded an adjustment to the right-of-use asset and lease liability in the amount of approximately $4,826,000.

On July 20, 2020, the Company entered into a third amendment to the Additional Laboratory Lease. Pursuant to the amendment the term of the lease was extended to June 14, 2022. The Company determined that the amendment should be accounted for as a lease modification applicable under ASC 842, not as a separate contract, with an effective date of lease modification of August 4, 2020, when the agreement was fully executed. At the effective date of modification, the Company recorded an adjustment to the right-of-use asset and lease liability in the amount of approximately $813,000.

At December 31, 2020, the Company recorded approximately $6,774,000 to operating right-of-use asset, and approximately $4,777,000 and $2,369,000 to short and long-term operating lease liability, respectively. At December 31, 2020 the remaining lease term was 1.46 years.

Future minimum lease payments under these leases at December 31, 2020 are as follows:

Year
2021		5,079,642
2022		2,407,692
Total lease payments		7,487,334
Less: present value discount		(341,121	)
Present value of lease payments	$	7,146,213

Total rent expense of approximately $4,593,000 and $4,474,000 was included in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2020 and 2019, respectively.

Contingencies

The Company accrues for 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, 2020, 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.

Cue Biopharma 401(k) Plan

12 Months Ended

Dec. 31, 2020

Compensation And Retirement Disclosure [Abstract]

Cue Biopharma 401(k) Plan

15.	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 did not make any contributions to the Plan during the year ended December 31, 2020 or 2019.

Subsequent Events

12 Months Ended

Dec. 31, 2020

Subsequent Events [Abstract]

Subsequent Events

16.	Subsequent Events

The Company has evaluated subsequent events through the date on which the consolidated financial statements were issued, to ensure that this submission includes appropriate disclosure of events both recognized in the consolidated financial statements and events which occurred subsequently but were not recognized in the consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Basis of Presentation

Public Offerings

Consolidation

Reclassifications

Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations.

Use of Estimates

Cash Concentrations

Cash and Cash Equivalents

Marketable Securities

Restricted Cash

The Company purchased a $150,000 certificate of deposit to collateralize a credit card account with a commercial bank that was classified as short-term certificate of deposit as of December 31, 2020.

Property and Equipment

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

Trademark

Revenue Recognition

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,
	2020		2019
Common stock warrants		861,969		1,189,827
Common stock options		5,030,899		4,793,253
Nonvested restricted stock units		230,002		66,667
Total		6,122,870		6,049,747

Fair Value of Financial Instruments

Recent Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

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,
	2020		2019
Common stock warrants		861,969		1,189,827
Common stock options		5,030,899		4,793,253
Nonvested restricted stock units		230,002		66,667
Total		6,122,870		6,049,747

Fair Value (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value Assets Measured on Recurring Basis

	Fair Value Measurements as of December 31, 2020
	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	72,943,275	$	—	$	—	$	72,943,275
Marketable securities		—		10,002,550		—		10,002,550
Total	$	72,943,275	$	10,002,550	$	—	$	82,945,825

	Fair Value Measurements as of December 31, 2019
	Level 1		Level 2		Level 3		Fair Value
Cash equivalents	$	39,303,609	$	—	$	—	$	39,303,609
Marketable securities		—		15,119,925		—		15,119,925
Total	$	39,303,609	$	15,119,925	$	—	$	54,423,534

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2020

Investments Debt And Equity Securities [Abstract]

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

As of December 31, 2020 and 2019, the fair value of available-for-sale marketable securities by type of security was as follows:

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury Securities	$	9,995,419	$	7,131	$	—		$	10,002,550
	$	9,995,419	$	7,131	$	—		$	10,002,550

	December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury Securities	$	15,130,246	$	—	$	(10,321	)	$	15,119,925
	$	15,130,246	$	—	$	(10,321	)	$	15,119,925

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property Plant And Equipment [Abstract]

Summary of Property and Equipment

Property and equipment as of December 31, 2020 and 2019 is summarized as follows:

	December 31,
	2020			2019
Laboratory equipment	$	4,148,426		$	3,587,559
Furniture and fixtures		93,321			93,321
Computer equipment		267,837			192,092
Construction in progress		405,019			—
		4,914,603			3,872,972
Less accumulated depreciation		(2,806,579	)		(2,026,050	)
Net property and equipment	$	2,108,024		$	1,846,922

Summary of Depreciation Expense

	Years Ended December 31,
	2020		2019
General and administrative	$	20,301	$	60,974
Research and development		760,228		738,140
Total	$	780,529	$	799,114

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2020

Accrued Liabilities Current [Abstract]

Summary of Accrued Expenses

Accrued expenses as of December 31, 2020 and 2019 is summarized as follows:

	December 31,
	2020		2019
Accrued compensation	$	1,963,983	$	1,575,821
Contract manufacturing services		108,880		150,250
Professional Services		326,028		383,910
Contract research services		388,320		117,371
	$	2,787,211	$	2,227,352

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Schedule of Estimated Fair Value of Each Stock Option Award

	December 31,
	2020	2019
Risk-free interest rate	0.38 to 1.56%	1.75 to 2.58%
Expected dividend yield	0%	0%
Expected volatility	93.4-99.6%	88.0-94.0%
Expected life	5.5 to 6.25 years	4.0 to 6.25 years

Summary of Stock Option Activity

A summary of stock option activity for the years ended December 31, 2020 is as follows:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in Years)
Stock options outstanding at December 31, 2018		4,540,321		$	7.08		5.16
Granted		1,288,100
Exercised		(485,105	)
Cancelled		(550,063	)
Stock options outstanding at December 31, 2019		4,793,253		$	7.10		5.64
Granted		981,800			17.31
Exercised		(454,497	)		4.86
Cancelled		(289,657	)		10.14
Stock options outstanding at December 31, 2020		5,030,899		$	9.10		5.51
Stock options exercisable at December 31, 2020		2,920,318		$	7.05		4.03

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

Stock-based compensation for the years ended December 31, 2020 and 2019 was included in the consolidated statements of operations and comprehensive loss as follows:

	December 31,
	2020		2019
General and administrative	$	4,093,542	$	2,109,335
Research and development		6,387,240		4,411,647
Total	$	10,480,782	$	6,520,982

Two Thousand Sixteen Omnibus Incentive Plan

Schedule of Nonvested Restricted Stock Units Activity

The following table summarizes the RSU activity for the under the Omnibus Plan for the year ending December 31, 2020:

Restricted Securities	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance as of December 31, 2019		66,667		$	7.53
Granted		220,000			17.96
Vested/Released		(56,665	)		10.94
Forfeited		—			—
Nonvested balance at December 31, 2020		230,002		$	16.66

Warrants (Table)

12 Months Ended

Dec. 31, 2020

Warrants And Rights Note Disclosure [Abstract]

Summary of Common Stock Warrant Activity

The following table summarizes common stock warrant activity for the year ended December 31, 2020:

	Warrant Issued June 15, 2015 Tranche 1			Warrant Issued December 27, 2017 Tranche 2			Total
Balance at December 31, 2019		322,259			867,568			1,189,827
Issued via cashless exercises		(227,184	)		(50,995	)		(278,179	)
Withheld as payment to cover issued shares		(22,464	)		(27,215	)		(49,679	)
Balance at December 31, 2020		72,611			789,358			861,969

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets as of December 31, 2020 and 2019 are as follows:

	2020			2019
Deferred tax assets:
Net operating loss carryforwards	$	34,539,000		$	23,348,000
Research and other credits		2,312,000			2,069,000
Reserves and accruals		7,446,000			5,281,000
Other		—			3,000
Total gross deferred tax assets		44,297,000			30,701,000
Less valuation allowance		(42,321,000	)		(29,095,000	)
Total deferred tax assets		1,976,000			1,606,000
Deferred tax liability:
Depreciation		(1,974,000	)		(1,606,000	)
Other		(2,000	)		—
Net deferred tax assets	$	—		$	—

Schedule of Reconciliation of Federal Statutory Rate and Effective Tax Rate

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, 2020, 2019, and 2018 is as follows:

	Years Ended December 31,
	2020			2019
U. S. Federal statutory tax rate		(21	)%		(21	)%
State Taxes		(7	)%		(6	)%
Change in valuation allowance		30	%		27	%
Tax credits		(1	)%		(2	)%
Stock based compensation		(2	)%		1	%
Tax reform		0	%		0	%
Foreign withholding taxes		0	%		1	%
Other		1	%		1	%
Effective tax rate		0	%		1	%

Schedule of Reconciliation of Gross Uncertain Tax Position

The following is a reconciliation of the Company’s gross uncertain tax position at December 31, 2020 and 2019:

	Year Ended December 31,
	2020		2019
Balance at the beginning of year	$	1,334,000	$	972,000
Additions for current year tax provisions		341,000		294,000
Additions for prior year tax provisions		—		81,000
Reductions of prior year tax provisions		—		(13,000	)
Balance as of end of year	$	1,675,000	$	1,334,000

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments for Operating Lease

Future minimum lease payments under these leases at December 31, 2020 are as follows:

Year
2021		5,079,642
2022		2,407,692
Total lease payments		7,487,334
Less: present value discount		(341,121	)
Present value of lease payments	$	7,146,213

Organization and Basis of Presentation - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Date of incorporation	Dec. 31, 2014
Cash, cash equivalents and marketable securities	$ 84.9

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Summary Of Significant Accounting Policies [Line Items]
Acquired intangible asset, useful life		15 years
Amortization related to trademark		$ 11,666	$ 11,667
Operating lease, right-of-use asset		6,774,229	5,337,026
Operating lease, liability		7,146,213
Income tax expense		206,250	412,500
Cash equivalents		72,943,275	39,303,609
Short-term marketable securities		10,002,550	15,119,925
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease, right-of-use asset		6,774,000		$ 9,692,000
Operating lease, liability				$ 9,347,000
Laboratory Equipment
Summary Of Significant Accounting Policies [Line Items]
Disposals of property and equipment		0	181,000
Loss on disposal of property and equipment			(54,000)
General and Administrative Expense
Summary Of Significant Accounting Policies [Line Items]
Patent expenses		$ 1,879,000	$ 1,934,000
Type of Cost, Good or Service [Extensible List]		us-gaap:LicenseMember	us-gaap:LicenseMember
Certificate of Deposit
Summary Of Significant Accounting Policies [Line Items]
Short-term restricted cash		$ 150,000
Stifel Nicolaus and Company Inc. \| Sales Agreement June 2019
Summary Of Significant Accounting Policies [Line Items]
Stock Issued During Period, Shares, New Issues		3,584,945
Proceeds from sale of common stock		$ 29,400,000
Stifel Nicolaus and Company Inc. \| Sales Agreement June 2019 \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Proceeds from Issuance Initial Public Offering		$ 30,000,000
Stifel Nicolaus and Company Inc. \| Sales Agreement November 2019 \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Proceeds from Issuance Initial Public Offering	$ 20,000,000
Stifel Nicolaus and Company Inc. \| Sales Agreement November 2019 \| Transaction Expense
Summary Of Significant Accounting Policies [Line Items]
Stock Issued During Period, Shares, New Issues		1,729,110
Proceeds from sale of common stock		$ 19,600,000
Stifel Nicolaus and Company Inc. \| Sales Agreement March 2020 \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Proceeds from Issuance Initial Public Offering		$ 35,000,000
Stifel Nicolaus and Company Inc. \| Sales Agreement March 2020 \| Transaction Expense
Summary Of Significant Accounting Policies [Line Items]
Stock Issued During Period, Shares, New Issues		1,824,901
Proceeds from sale of common stock		$ 34,300,000
Stifel Nicolaus and Company Inc. \| Sales Agreement June 2020 \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Proceeds from Issuance Initial Public Offering		$ 40,000,000
Stifel Nicolaus and Company Inc. \| Sales Agreement June 2020 \| Transaction Expense
Summary Of Significant Accounting Policies [Line Items]
Stock Issued During Period, Shares, New Issues		1,192,000
Proceeds from sale of common stock		$ 22,400,000

Summary of Significant Accounting Policies - Summary of Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2020
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

Summary of Significant Accounting Policies - Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	6,122,870	6,049,747
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	861,969	1,189,827
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,030,899	4,793,253
Nonvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	230,002	66,667

Fair Value - Schedule of Fair Value Assets Measured on Recurring Basis (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 72,943,275	$ 39,303,609
Marketable securities	10,002,550	15,119,925
Fair Value Measurements, Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	72,943,275	39,303,609
Marketable securities	10,002,550	15,119,925
Total	82,945,825	54,423,534
Fair Value Measurements, Recurring Basis \| Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	72,943,275	39,303,609
Total	72,943,275	39,303,609
Fair Value Measurements, Recurring Basis \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	10,002,550	15,119,925
Total	$ 10,002,550	$ 15,119,925

Fair Value - Additional Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value assets transfers between Level 2 and Level 3	$ 0	$ 0

Marketable Securities - Schedule of Fair Value of Available-for-Sale Marketable Securities (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 9,995,419	$ 15,130,246
Gross Unrealized Gains	7,131
Gross Unrealized Losses		(10,321)
Fair Value	10,002,550	15,119,925
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	9,995,419	15,130,246
Gross Unrealized Gains	7,131
Gross Unrealized Losses		(10,321)
Fair Value	$ 10,002,550	$ 15,119,925

Marketable Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Marketable securities	$ 10,002,550	$ 15,119,925
Unrealized gain on investments	$ 17,452	$ 637

Property and Equipment - Summary of Property and Equipment (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 4,914,603	$ 3,872,972
Less accumulated depreciation	(2,806,579)	(2,026,050)
Net property and equipment	2,108,024	1,846,922
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	4,148,426	3,587,559
Less accumulated depreciation		(139,003)
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	93,321	93,321
Computer Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	267,837	$ 192,092
Construction in Progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 405,019

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Depreciation	$ 11,666	$ 11,667
Amortization of capitalized license expense	265,263
Accumulated depreciation and amortization	2,806,579	2,026,050
Laboratory Equipment
Property Plant And Equipment [Line Items]
Disposal of property and equipment, gross		320,778
Accumulated depreciation and amortization		139,003
Loss on disposal of property and equipment		$ 54,274
Disposals of property and equipment	$ 0

Property and Equipment - Summary of Depreciation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Depreciation expense	$ 780,529	$ 799,114
General and Administrative Expense
Property Plant And Equipment [Line Items]
Depreciation expense	20,301	60,974
Research and Development
Property Plant And Equipment [Line Items]
Depreciation expense	$ 760,228	$ 738,140

Summary of Accrued Expenses (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Accrued compensation	$ 1,963,983	$ 1,575,821
Contract manufacturing services	108,880	150,250
Professional services	326,028	383,910
Contract research services	388,320	117,371
Accrued expenses	$ 2,787,211	$ 2,227,352

Einstein License and Service Agreement - Additional Information (Details)			12 Months Ended
	Dec. 27, 2017 shares	Jan. 14, 2015	Dec. 31, 2020 USD ($) SupportingTechnology	Dec. 31, 2019 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Prepaid expenses and other current assets			$ 1,241,239	$ 860,107
Other long term assets			$ 401,667	673,625
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			$ 150,000
Stock Issued During Period, Shares, New Issues \| shares	671,572
Costs incurred			75,000	565,659
Capitalized costs incurred			416,855	525,554
Prepaid expenses and other current assets				265,262
Other long term assets				260,292
Einstein License Agreement \| Research and Development
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Costs incurred			$ 75,000	$ 50,000
Type of Cost, Good or Service [Extensible List]			cue:LicensedProductsMember	cue:LicensedProductsMember

Stock-Based Compensation - Additional Information (Details) - USD ($)			1 Months Ended		12 Months Ended
	Jan. 21, 2020	Aug. 13, 2017	May 31, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Aug. 21, 2020	Oct. 03, 2019	Aug. 12, 2017	Mar. 23, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					981,800	1,288,100
Common stock reserved for issuance					755,725
Stock-based compensation					$ 10,480,782	$ 6,520,982
Unrecognized stock-based compensation					15,605,021
Intrinsic value of exercisable stock options					$ 16,869,399	$ 19,471,155
Intrinsic value of exercisable fair value per share					$ 7.05	$ 6.26
Fair value of option					12.51
Weighed Average Exercise Price, Exercisable					$ 7.05
Weighted Average Remaining Contractual Life (in Years), Exercisable					4 years 10 days
Number of Shares, Granted					981,800	1,288,100
Unvested weighted average exercise price	$ 7.83
Unvested share purchase	94,375
Post-employment options exercise period	12 months		36 months
Stock-based compensation					$ 10,480,782	$ 6,520,982
Equity Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation					8,861,760	6,208,949
Additional compensation modification cost					$ 344,850
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					220,000
Unrecognized stock-based compensation						$ 2,772,845
Number of Shares, Granted					220,000
Unvested share purchase						100,000	20,000	100,000
Weighted average grant date fair value per share						$ 7.53
Stock-based compensation					$ 1,619,022	$ 312,032
Restricted Stock Units \| February2020 Awarded And Granted
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					150,000
Number of Shares, Granted					150,000
Restricted Stock Units \| March2020 Awarded And Granted
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted				50,000
Number of Shares, Granted				50,000
Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					320,000
Number of Shares, Granted					320,000
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted	215,000				981,800
Number of Shares, Granted	215,000				981,800
Weighted average exercise price	$ 6.22
Common Stock \| Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					4,940,901
Number of Shares, Granted					4,940,901
Two Thousand Sixteen Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance					750,325
Two Thousand Sixteen Omnibus Incentive Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					320,000
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
Stock option granted					4,459,301
Number of Shares, Granted					4,459,301
2016 Non-Employee Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted					481,600
Common stock reserved for issuance					5,400
Number of Shares, Granted					481,600
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 \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested weighted average exercise price					$ 16.66	$ 7.53
Unvested share purchase					230,002	66,667
Weighted average grant date fair value per share					$ 17.96
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%

Stock-Based Compensation - Schedule of Estimated Fair Value of Each Stock Option Award (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.75%	2.43%
Risk-free interest rate, maximum	2.58%	2.95%
Expected dividend yield	0.00%	0.00%
Expected volatility, minimum	88.00%	82.00%
Expected volatility, maximum	94.00%	83.60%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life	5 years 6 months	4 years
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life	6 years 3 months	6 years 3 months

Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Number of Shares, Outstanding Beginning Balance	4,793,253	4,540,321
Number of Shares, Granted	981,800	1,288,100
Number of Shares, Exercised	(454,497)	(485,105)
Number of Shares, Cancelled	(289,657)	(550,063)
Number of Shares, Outstanding Ending Balance	5,030,899	4,793,253	4,540,321
Number of Shares, Exercisable	2,920,318
Weighted Average Exercise Price, Outstanding Beginning Balance	$ 7.10	$ 7.08
Weighted Average Exercise Price, Granted	17.31
Weighted Average Exercise Price, Exercised	4.86
Weighted Average Exercise Price, Cancelled	10.14
Weighted Average Exercise Price, Outstanding Ending Balance	9.10	$ 7.10	$ 7.08
Weighed Average Exercise Price, Exercisable	$ 7.05
Weighted Average Remaining Contractual Life (in Years)	5 years 6 months 3 days	5 years 7 months 20 days	5 years 1 month 28 days
Weighted Average Remaining Contractual Life (in Years), Exercisable	4 years 10 days

Stock-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Details) - Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Nonvested balance as of December 31, 2018	100,000
Number of Shares, Nonvested balance at December 31, 2019		100,000
Weighted average grant date fair value per share		$ 7.53
Omnibus Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Nonvested balance as of December 31, 2018	66,667
Number of Shares, Granted	220,000
Number of Shares, Vested/Released	(56,665)
Number of Shares, Nonvested balance at December 31, 2019	230,002	66,667
Weighted Average Grant Date Fair Value Per Share, Nonvested balance as of December 31, 2018	$ 7.53
Weighted average grant date fair value per share	17.96
Weighted Average Grant Date Fair Value Per Share, Vested/Released	10.94
Weighted Average Grant Date Fair Value Per Share, Nonvested balance at December 31, 2019	$ 16.66	$ 7.53

Stock-Based Compensation - Schedule of Stock-Based Compensation Included in Statement of Operations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	$ 10,480,782	$ 6,520,982
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	4,093,542	2,109,335
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	$ 6,387,240	$ 4,411,647

Warrants - Additional Information (Details)	12 Months Ended
Warrants - Additional Information (Details)	Dec. 31, 2020 USD ($) Tranche $ / shares shares	Dec. 31, 2019 shares	Dec. 27, 2017 $ / shares shares	Jun. 15, 2015 $ / shares
Class Of Warrant Or Right [Line Items]
Number of tranches \| Tranche	2
Common stock warrants outstanding \| shares	861,969	1,189,827
First tranche
Class Of Warrant Or Right [Line Items]
Common stock warrants outstanding \| shares	370,370
Exercise price of common stock warrants \| $ / shares				$ 2.70
Common stock warrants life				7 years
Common stock warrants expiration date	Jun. 15, 2022
Warrant
Class Of Warrant Or Right [Line Items]
Fair value of common stock \| $ / shares	$ 12.51
Intrinsic value of common stock warrants \| $	$ 3,187,000
Second tranche
Class Of Warrant Or Right [Line Items]
Common stock warrants outstanding \| shares			882,071
Exercise price of common stock warrants \| $ / shares			$ 9.38
Common stock warrants life	5 years
Common stock warrants expiration date	Dec. 26, 2022

Warrants - Summary of Common Stock Warrant Activity (Details)	12 Months Ended
	Dec. 31, 2020 shares
Class Of Warrant Or Right [Line Items]
Balance at December 31, 2019	1,189,827
Issued via cashless exercises	(278,179)
Withheld as payment to cover issued shares	(49,679)
Balance at December 31, 2020	861,969
First tranche
Class Of Warrant Or Right [Line Items]
Balance at December 31, 2019	322,259
Issued via cashless exercises	(227,184)
Withheld as payment to cover issued shares	(22,464)
Balance at December 31, 2020	72,611
Warrant Tranche 2
Class Of Warrant Or Right [Line Items]
Balance at December 31, 2019	867,568
Issued via cashless exercises	(50,995)
Withheld as payment to cover issued shares	(27,215)
Balance at December 31, 2020	789,358

Revenue Recognition - Additional Information (Details) - USD ($)					1 Months Ended		12 Months Ended
	Dec. 07, 2020	Nov. 18, 2020	May 16, 2019	Nov. 14, 2017	Dec. 31, 2020	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 06, 2018
Disaggregation Of Revenue [Line Items]
Transaction price recorded in liabilities					$ 2,500,000		$ 2,500,000
Collaboration revenue							3,154,325	$ 3,458,331
Short-term research and development contract liability					6,681,025		6,681,025	4,097,443
Long-term research and development contract liability					1,937,575		1,937,575	4,017,894
Income tax expense							206,250	412,500
Prepaid expenses and other short-term assets					1,241,239		1,241,239	860,107
Other long-term assets					401,667		401,667	673,625
Amortization of Intangible Assets							11,666	11,667
Collaboration Agreement with Merck \| Merck
Disaggregation Of Revenue [Line Items]
Up front non refundable payment				$ 2,500,000
Achievement of certain research and development milestones				120,000,000
Achievement of certain commercial milestones				150,000,000
Milestone payments received				2,500,000
Collaboration revenue							177,000	874,000
Short-term research and development contract liability					606,771		606,771	483,515
Long-term research and development contract liability					0		0	0
Collaboration Agreement with Merck \| Merck \| Maximum
Disaggregation Of Revenue [Line Items]
Eligible to earn achievement of certain research and development milestones				$ 101,000,000
First Amendment to Merck
Disaggregation Of Revenue [Line Items]
Milestone payments received		$ 300,000
Milestone payment associated with contract liability		$ 300,000
Collaboration Agreement with LG Chem Life Sciences \| LG Chem Life Sciences
Disaggregation Of Revenue [Line Items]
Milestone payments received	$ 1,250,000		$ 2,500,000
Milestone payment associated with contract liability	1,250,000		2,500,000
Collaboration revenue							2,978,000	$ 2,584,000
Short-term research and development contract liability					6,074,254		6,074,254
Long-term research and development contract liability					1,937,575		1,937,575
Equity investment nonrefundable upfront cash payment										$ 5,000,000.0
Equity investment for research collaboration agreement										5,000,000.0
Income tax expense	$ 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
Einstein License And Service Agreement \| Einstein
Disaggregation Of Revenue [Line Items]
License expenses					156,600	$ 313,000	907,600		$ 438,000
Prepaid expenses and other short-term assets					416,900		416,900
Other long-term assets					$ 0		0
Amortization of Intangible Assets							$ 490,700

Revenue Recognition - Additional Information (Details1) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-07-01	Dec. 31, 2020
Current Liabilities \| Maximum
Disaggregation Of Revenue [Line Items]
Revenue expected to be recognized	12 months
Contract Liabilities \| Minimum [Member]
Disaggregation Of Revenue [Line Items]
Revenue expected to be recognized	12 months

Stockholders' Equity - Additional Information (Details) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Stockholders Equity [Abstract]
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares issued	0	0
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares issued	30,351,366	26,562,178
Common stock, shares outstanding	30,351,366	26,562,178

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Tax provision related to foreign withholding tax	$ 206,250	$ 412,500
Percentage of valuation allowance against deferred tax assets	100.00%	100.00%
Unrecognized tax benefits	$ 1,675,000	$ 1,334,000	$ 972,000
Federal
Income Taxes [Line Items]
Operating loss carryforwards	$ 126,941,033
Operating loss carryforwards expiration start year	2035
Net operating losses indefinite carryforward amount	$ 98,429,255
State
Income Taxes [Line Items]
Operating loss carryforwards	$ 126,360,676
Operating loss carryforwards expiration start year	2035
Research Tax Credit
Income Taxes [Line Items]
Prepaid amount to be offset against payroll tax liabilities	$ 250,000
Prepaid amount to be offset against payroll tax liabilities remaining from previous year	250,000
Research Tax Credit \| Federal
Income Taxes [Line Items]
Unrecognized tax benefits	1,675,000
Tax credits	$ 2,993,000
Tax credits carryforward expiration start year	2035
Research Tax Credit \| State
Income Taxes [Line Items]
Unrecognized tax benefits		$ 1,334,000
Tax credits	$ 1,151,000
Tax credits carryforward expiration start year	2031

Income Taxes - Schedule of Components of Deferred Tax Assets (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 34,539,000	$ 23,348,000
Research and other credits	2,312,000	2,069,000
Reserves and accruals	7,446,000	5,281,000
Other	(2,000)	3,000
Total gross deferred tax assets	44,297,000	30,701,000
Less valuation allowance	(42,321,000)	(29,095,000)
Total deferred tax assets	1,976,000	1,606,000
Deferred tax liability:
Depreciation	(1,974,000)	(1,606,000)
Other	$ (2,000)	$ 3,000

Income Taxes - Schedule of Reconciliation of Federal Statutory Rate and Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
U. S. Federal statutory tax rate	(21.00%)	(21.00%)
State Taxes	(7.00%)	(6.00%)
Change in valuation allowance	30.00%	27.00%
Tax credits	(1.00%)	(2.00%)
Stock based compensation	(2.00%)	1.00%
Tax reform	0.00%	0.00%
Foreign withholding taxes	0.00%	1.00%
Other	1.00%	1.00%
Effective tax rate	0.00%	1.00%

Income Taxes - Schedule of Reconciliation of Gross Uncertain Tax Position (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance at the beginning of year	$ 1,334,000	$ 972,000
Additions for current year tax provisions	341,000	294,000
Additions for prior year tax provisions		81,000
Reductions of prior year tax provisions		(13,000)
Balance as of end of year	$ 1,675,000	$ 1,334,000

Commitments and Contingencies - Additional Information (Details)								12 Months Ended
	Jul. 20, 2020	Jun. 24, 2020 USD ($)	Oct. 01, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 20, 2018 USD ($)	Jun. 18, 2018	May 01, 2018	Dec. 31, 2020 USD ($) ft²	Dec. 31, 2019 USD ($)	Dec. 31, 2018	Jan. 01, 2019 USD ($)
Commitments And Contingencies [Line Items]
Lease agreement description							Upon execution of this lease agreement the Company prepaid three months of rent, two of which will be held in escrow and credited against future rent payments and that the other of which was applied to the first months’ rent. The Company also prepaid seven and one half months’ rent pursuant to an amendment to the lease agreement executed on June 18, 2018. These amounts were recorded to deposits and prepaid expenses, respectively, at December 31, 2020
Additional lease agreement description										The monthly rental rate under the Additional Laboratory Lease was $72,600 for the first 12 months and $78,600 for the remainder of the term. Upon execution of this lease agreement the Company prepaid 12 months’ rent pursuant to the lease agreement executed on September 20, 2018.
Rent expense								$ 4,593,000	$ 4,474,000
Operating lease right-of-use								$ 6,774,229	$ 5,337,026
ASU 2016-02
Commitments And Contingencies [Line Items]
Lease term								1 year 5 months 15 days
Reduction to right-of-use asset			$ 335,465
Decrease In Lease Liability			327,079
Loss on Right Of Use Asset			$ 8,386
Operating lease right-of-use								$ 6,774,000			$ 9,692,000
Operating lease liability short term								4,777,000
Operating lease liability long term								2,369,000
Operating Lease Agreement
Commitments And Contingencies [Line Items]
Lease expiration date					Apr. 14, 2021		Apr. 30, 2021
Lease agreement effective date					Oct. 15, 2018		May 01, 2018
Lessee operating lease monthly rental rate								330,550
Lessee operating lease monthly rental payments for remaining term					$ 78,600			$ 375,174
Lessee operating lease monthly rental payments for first twelve months					$ 72,600
Amended Lease Agreement
Commitments And Contingencies [Line Items]
Lease expiration date			Apr. 14, 2021			Apr. 14, 2021
Lease agreement effective date			Oct. 01, 2019			May 15, 2018
Rent expense			$ 58,995	$ 78,600
Operating lease, weighted average discount rate								6.00%
Laboratory And Office Lease \| ASU 2016-02
Commitments And Contingencies [Line Items]
Lease agreement description		Pursuant to the amendment (1) the term of the lease was extended to June 14, 2022 and (2) the monthly rental rate for the last 14 months of the lease term was increased to $375,174. The Company determined that the amendment should be accounted for as a lease modification applicable under ASC 842, not as a separate contract, with an effective date of lease modification of May 14, 2020.
Lease monthly rental payments		$ 375,174
Adjustment related to right of use asset lease liability								$ 4,826,000
Lease extended date		Jun. 14, 2022
Lease modification date		May 14, 2020
Additional Laboratory Lease Third Amendment \| ASU 2016-02
Commitments And Contingencies [Line Items]
Lease agreement description	On July 20, 2020, the Company entered into a third amendment to the Additional Laboratory Lease. Pursuant to the amendment the term of the lease was extended to June 14, 2022. The Company determined that the amendment should be accounted for as a lease modification applicable under ASC 842, not as a separate contract, with an effective date of lease modification of August 4, 2020, when the agreement was fully executed
Adjustment related to right of use asset lease liability								$ 813,000
Lease extended date	Jun. 14, 2022
Lease modification date	Aug. 04, 2020
Cambridge, Massachusetts
Commitments And Contingencies [Line Items]
Office space for lease \| ft²								19,900
Leases beginning date								May 31, 2018
Lease expiration date								Apr. 14, 2021
Present value of lease payments, discounting rate											6.00%
Lease term									2 years 3 months 18 days
Albert Einstein College Of Medicine \| Einstein License And Service Agreement
Commitments And Contingencies [Line Items]
Milestone payments for each product, process or service								$ 1,850,000
Milestone payments for each new indication of licensed product								1,850,000
Aggregate amount of additional milestone payments								$ 5,750,000

Commitments and Contingencies - Schedule of Future Minimum Lease Payments on Operating Leases (Details)	Dec. 31, 2020 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2021	$ 5,079,642
2022	2,407,692
Total lease payments	7,487,334
Less: present value discount	(341,121)
Present value of lease payments	$ 7,146,213

Cue Biopharma 401(k) Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Company Contribution	$ 0	$ 0

- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References + Details