NexImmune (NEXI) 10-Q 12 Nov 21 2021 Q3 Quarterly report Financial data

Cover

Cover	9 Months Ended
	Sep. 30, 2021shares
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-40045
Entity Registrant Name	NEXIMMUNE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	42-2518457
Entity Address, Address Line One	9119 Gaither Road
Entity Address, City or Town	Gaithersburg,
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20877
City Area Code	301
Local Phone Number	825-9810
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	NEXI
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	22,711,247
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2021
Entity Central Index Key	0001538210

Balance Sheets

Balance Sheets - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 37,256,427	$ 5,031,079
Marketable securities	55,986,355	0
Restricted cash	67,500	67,500
Prepaid expenses and other current assets	5,416,575	3,293,858
Total current assets	98,726,857	8,392,437
Property and equipment, net	4,287,254	2,885,260
Other non-current assets	1,527,596	23,373
Total assets	104,541,707	11,301,070
Current liabilities:
Accounts payable	3,501,098	2,760,129
Accrued expenses	3,931,449	2,603,027
Derivative liability	0	1,702,359
Other current liabilities	0	843,619
Convertible notes issued to related parties	0	7,324,267
Convertible notes	0	11,793,397
Total current liabilities	7,432,547	27,026,798
Deferred rent, net of current portion	0	23,529
Other non-current liabilities	0	4,935
Total liabilities	7,432,547	27,055,262
Commitments and contingencies
Redeemable convertible preferred stock
Total redeemable convertible preferred stock	0	53,620,749
Stockholders’ equity (deficit)
Common Stock, $0.0001 par value, 250,000,000 shares authorized, 22,711,247 issued and outstanding as of September 30, 2021 and 1,256,609 shares issued and outstanding as of December 31, 2020.	2,271	126
Additional paid-in-capital	209,324,044	8,206,938
Accumulated other comprehensive income	702	0
Accumulated deficit	(112,217,857)	(77,582,005)
Total stockholders’ equity (deficit)	97,109,160	(69,374,941)
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	104,541,707	11,301,070
Series A Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock
Total redeemable convertible preferred stock	0	35,047,435
Series A-2 Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock
Total redeemable convertible preferred stock	0	7,685,865
Series A-3 Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock
Total redeemable convertible preferred stock	$ 0	$ 10,887,449

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Authorized common stock (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	22,711,247	1,256,609
Common stock, shares outstanding (in shares)	22,711,247	1,256,609
Series A Redeemable Convertible Preferred Stock
Temporary equity, per share (in dollars per share)	$ 0.0001	$ 0.0001
Temporary equity, shares outstanding (in shares)	0	121,735,303
Temporary equity, shares authorized (in shares)		121,735,303
Temporary equity, shares issued (in shares)		121,735,303
Temporary equity, liquidation preference (in shares)		$ 42,314,789
Series A-2 Redeemable Convertible Preferred Stock
Temporary equity, per share (in dollars per share)	$ 0.0001	$ 0.0001
Temporary equity, shares outstanding (in shares)	0	22,047,361
Temporary equity, shares authorized (in shares)		28,384,899
Temporary equity, shares issued (in shares)		22,047,361
Temporary equity, liquidation preference (in shares)		$ 8,683,746
Series A-3 Redeemable Convertible Preferred Stock
Temporary equity, per share (in dollars per share)	$ 0.0001	$ 0.0001
Temporary equity, shares outstanding (in shares)	0	31,209,734
Temporary equity, shares authorized (in shares)		34,061,879
Temporary equity, shares issued (in shares)		31,209,734
Temporary equity, liquidation preference (in shares)		$ 11,699,176

Statements Of Operations

Statements Of Operations - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	11,331,189	4,913,055	25,468,770	13,394,483
General and administrative	4,159,196	2,752,251	12,254,838	7,406,054
Total operating expenses	15,490,385	7,665,306	37,723,608	20,800,537
Loss from operations	(15,490,385)	(7,665,306)	(37,723,608)	(20,800,537)
Other income (expense):
Interest income	19,855	812	30,319	20,680
Change in fair value of derivative liability	0	(397,244)	2,424,877	(397,244)
Gain on extinguishment of debt	843,619	0	843,619	0
Interest expense	(1,106)	(559,325)	(905,326)	(743,996)
Other (expense) income	(19,095)	12,328	(45,791)	66,329
Other income (expense)	843,273	(943,429)	2,347,698	(1,054,231)
Net loss	(14,647,112)	(8,608,735)	(35,375,910)	(21,854,768)
Accumulated dividends on Redeemable Convertible Preferred Stock	0	(824,781)	(377,562)	(2,456,413)
Net loss attributable to common stockholders	$ (14,647,112)	$ (9,433,516)	$ (35,753,472)	$ (24,311,181)
Basic net loss attributable to common stockholders per common share (in dollars per share)	$ (0.65)	$ (7.52)	$ (1.85)	$ (19.38)
Diluted net loss attributable to common stockholders per common share (in dollars per share)	$ (0.65)	$ (7.52)	$ (1.85)	$ (19.38)
Basic weighted average number of common shares outstanding (in shares)	22,653,410	1,254,808	19,335,170	1,254,724
Diluted weighted-average number of common shares outstanding (in shares)	22,653,410	1,254,808	19,335,170	1,254,724

Statements Of Comprehensive Los

Statements Of Comprehensive Loss - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (14,647,112)	$ (8,608,735)	$ (35,375,910)	$ (21,854,768)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale marketable securities, net of tax	3,619	0	702	(506)
Comprehensive loss	$ (14,643,493)	$ (8,608,735)	$ (35,375,208)	$ (21,855,274)

Statements Of Changes In Redeem

Statements Of Changes In Redeemable Convertible Preferred Stock And Stockholders' Equity (Deficit) - USD ($)	Total	Cumulative effect of adoption of accounting standard	Series A Redeemable Convertible Preferred Stock	Series A-2 Redeemable Convertible Preferred Stock	Series A-3 Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Additional Paid-in CapitalCumulative effect of adoption of accounting standard	Accumulated Deficit	Accumulated DeficitCumulative effect of adoption of accounting standard	Accumulated Other Comprehensive Income/ (Loss)
Balance at Dec. 31, 2019	$ (43,009,568)		$ 35,047,435	$ 7,685,865	$ 10,887,449	$ 126	$ 4,705,808		$ (47,716,008)		$ 506
Balance (in shares) at Dec. 31, 2019			121,735,303	22,047,361	31,209,734	1,254,681
Exercise of stock options (in shares)						271
Exercise of stock options	838						838
Stock-based compensation	943,210						943,210
Change in unrealized gains on marketable available-for-sale securities	(506)										(506)
Beneficial conversion feature on convertible notes	1,065,632						1,065,632
Net loss	(21,854,768)								(21,854,768)
Balance at Sep. 30, 2020	(62,855,162)		$ 35,047,435	$ 7,685,865	$ 10,887,449	$ 126	6,715,488		(69,570,776)		0
Balance (in shares) at Sep. 30, 2020			121,735,303	22,047,361	31,209,734	1,254,952
Balance at Jun. 30, 2020	(54,562,092)		$ 35,047,435	$ 7,685,865	$ 10,887,449	$ 126	6,399,823		(60,962,041)		0
Balance (in shares) at Jun. 30, 2020			121,735,303	22,047,361	31,209,734	1,254,681
Exercise of stock options (in shares)						271
Exercise of stock options	838						838
Stock-based compensation	284,458						284,458
Change in unrealized gains on marketable available-for-sale securities	0
Beneficial conversion feature on convertible notes	30,369						30,369
Net loss	(8,608,735)								(8,608,735)
Balance at Sep. 30, 2020	(62,855,162)		$ 35,047,435	$ 7,685,865	$ 10,887,449	$ 126	6,715,488		(69,570,776)		0
Balance (in shares) at Sep. 30, 2020			121,735,303	22,047,361	31,209,734	1,254,952
Balance at Dec. 31, 2020	(69,374,941)	$ (1,537,274)	$ 35,047,435	$ 7,685,865	$ 10,887,449	$ 126	8,206,938	$ (2,277,332)	(77,582,005)	$ 740,058	0
Balance (in shares) at Dec. 31, 2020			121,735,303	22,047,361	31,209,734	1,256,609
Issuance of Series A redeemable preferred stock upon exercise of warrants (in shares)			145,000
Issuance of Series A redeemable preferred stock upon exercise of warrants	0		$ 1,450
Conversion of preferred stock into common stock, Temporary equity (in shares)			(121,880,303)	(22,047,361)	(31,209,734)
Conversion of preferred stock into common stock			$ (35,048,885)	$ (7,685,865)	$ (10,887,449)
Conversion of preferred stock into common stock (in shares)						10,144,041
Conversion of preferred stock into common stock	53,622,199					$ 1,014	53,621,185
Conversion of convertible debt into common stock (in shares)						3,669,010
Conversion of convertible debt into common stock	30,252,056					$ 367	30,251,689
Issuance of common stock in connection with the initial public offering. net of transaction costs (in shares)						7,441,650
Issuance of common stock in connection with the initial public offering. net of transaction costs	$ 114,551,315					$ 744	114,550,571
Exercise of stock options (in shares)	197,041					197,041
Exercise of stock options	$ 661,657					$ 20	661,637
Exercise of warrants (in shares)						2,896
Stock-based compensation	4,309,356						4,309,356
Change in unrealized gain on marketable available-for-sale securities	702										702
Change in unrealized gains on marketable available-for-sale securities	702
Net loss	(35,375,910)								(35,375,910)
Balance at Sep. 30, 2021	97,109,160		$ 0	$ 0	$ 0	$ 2,271	209,324,044		(112,217,857)		702
Balance (in shares) at Sep. 30, 2021			0	0	0	22,711,247
Balance at Jun. 30, 2021	109,909,420		$ 0	$ 0	$ 0	$ 2,263	207,480,819		(97,570,745)		(2,917)
Balance (in shares) at Jun. 30, 2021			0	0	0	22,628,007
Exercise of stock options (in shares)						83,240
Exercise of stock options	214,802					$ 8	214,794
Stock-based compensation	1,628,431						1,628,431
Change in unrealized gain on marketable available-for-sale securities	3,619										3,619
Change in unrealized gains on marketable available-for-sale securities	3,619
Net loss	(14,647,112)								(14,647,112)
Balance at Sep. 30, 2021	$ 97,109,160		$ 0	$ 0	$ 0	$ 2,271	$ 209,324,044		$ (112,217,857)		$ 702
Balance (in shares) at Sep. 30, 2021			0	0	0	22,711,247

Statements Of Cash Flows

Statements Of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (35,375,910)	$ (21,854,768)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	627,043	448,108
Loss on asset disposal	7,877	(152)
Stock-based compensation	4,309,356	943,210
Non-cash interest expense	903,919	555,449
Change in fair value of derivative liability	(2,424,877)	397,244
Gain on extinguishment of debt	(843,619)	0
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(4,549,572)	(909,163)
Accounts payable	1,522,406	817,769
Accrued expenses, deferred rent and other	1,476,699	389,388
Net cash used in operating activities	(34,346,678)	(19,212,915)
Cash flows from investing activities
Purchase of property and equipment	(1,834,709)	(638,857)
Proceeds from disposal of equipment	464	550
Collections on employee advances	0	80,224
Purchase of marketable securities	(55,976,987)	0
Proceeds from maturities and sales of available-for-sale marketable securities	0	1,006,371
Net cash (used in) provided by investing activities	(57,811,232)	448,288
Cash flows from financing activities
Proceeds from initial public offering, net of transaction costs	114,721,518	0
Proceeds from the exercise of stock options	661,657	838
Proceeds from the exercise of warrants	1,450	0
Principal payments on capital leases	(12,260)	(14,773)
Proceeds from the issuance of convertible notes from related parties	56,500	2,900,460
Proceeds from the issuance of convertible notes	8,974,980	8,017,826
Issuance costs associated with convertible notes	(20,587)	(132,017)
Proceeds from the issuance of short-term debt	0	843,619
Net cash provided by financing activities	124,383,258	11,615,953
Net increase (decrease) in cash, cash equivalents and restricted cash	32,225,348	(7,148,674)
Net cash, cash equivalents and restricted cash at beginning of period	5,098,579	9,196,487
Net cash, cash equivalents and restricted cash at end of period	37,323,927	2,047,813
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	457	1,871
Supplemental disclosure of noncash investing and financing activities:
Gain on extinguishment of debt from PPP loan forgiveness	843,619	0
Property and equipment purchases included in accounts payable and accrued expenses	$ 272,844	$ 112,417

Nature of the business

Nature of the business	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the business	Nature of the businessNexImmune, Inc. (“Company”, “we”, “us” or “NexImmune”), a Delaware corporation headquartered in Gaithersburg, Maryland, was incorporated on June 7, 2011. The Company is an emerging biopharmaceutical company advancing a new generation of immunotherapies based on its proprietary Artificial Immune Modulation (AIM) technology. The AIM nanotechnology platform, originally developed at Johns Hopkins University, is the foundation for an innovative approach to immunotherapy in which the body’s own immune system is stimulated to orchestrate a targeted T cell response against a disease. Central to the AIM technology are AIM nanoparticles, which act as synthetic dendritic cells. These AIM nanoparticles can be programmed to present specific antigens and co-stimulatory signals to specific T cells, generating an immune response that can be directed toward any foreign substance or cell type in a patient’s body. The Company’s first two products, both for the treatment of different types of cancer, entered clinical trials in 2020.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited financial statements were prepared in accordance with the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, they do not include all of the information required by U.S. generally accepted accounting principles (“GAAP”) for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). These financial statements should be read in conjunction with our audited financial statements and the accompanying notes to our financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the SEC on March 31, 2021. In management’s opinion, the accompanying financial statements contain all adjustments, including normal, recurring adjustments, necessary to fairly present our financial position as of September 30, 2021 and December 31, 2020, and our statements of operations and comprehensive income, statements of changes in redeemable convertible preferred stock and stockholders’ equity (deficit), and statement of cash flows for the three and nine month periods ended September 30, 2021 and 2020. Interim results are not necessarily indicative of results for an entire year. Recent accounting standards and pronouncements Recently Adopted In August 2020, the FASB issued ASU 2020-06, an update to ASC Topic 470, Subtopic - 20, Debt - Debt with Conversion and Other Options, and ASC Topic 815, Subtopic - 4, Derivatives and Hedging - Contracts in Entity’s Own Equity . ASU 2020-06 simplifies the guidance for certain financial instruments with characteristics of liability and equity, including convertible instruments and contracts on an entity’s own equity by reducing the number of accounting models for convertible instruments and amends guidance in ASC Topic 260, Earnings Per Share, relating to the computation of earnings per share for convertible instruments and contracts on an entity’s own equity. ASU 2020-06 is effective for interim and annual reporting periods in fiscal years that begin after December 15, 2021, with early adoption permitted for fiscal years that begin after December 15, 2020. The Company early adopted this standard effective January 1, 2021 using the modified retrospective method. Under this standard, only conversion features embedded in the debt instrument that are accounted for as derivatives in accordance with ASC 815 or under the substantial premium model in ASC 470, require separate accounting. Prior to the adoption of this standard, the Company had recorded a beneficial conversion feature as a discount to convertible notes issued. Upon adoption of this standard, the beneficial conversion feature is no longer separately accounted. As a result of applying the modified retrospective method, the Company recognized a transition adjustment of $0.7 million recorded in accumulated deficit, a reduction of additional paid-in capital of $2.2 million and an increase to the carrying value of the convertible notes of $1.5 million on January 1, 2021. Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (ASC 842). The guidance amends the existing accounting standards for lease accounting, including requirements for lessees to recognize assets and liabilities related to long-term leases on the balance sheet and expanding disclosure requirements regarding leasing arrangements. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. In July 2018, the FASB issued additional guidance, which offers a transition option to entities adopting ASC 842 in which entities can elect to apply the new guidance using a modified retrospective approach at the beginning of the year in which the new lease standard is adopted.. The Company currently expects to utilize this transition option whereby financial information for prior periods presented before the ASC 842 effective date will not be updated. In November 2019, the FASB issued ASU 2019-10 deferring the effective date for private entities for fiscal years beginning after December 15, 2020 and interim periods within fiscal years beginning after December 15, 2021. In June 2020, the FASB issued ASU 2020-05 which further defers the effective date for private entities for fiscal years beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022. The Company will adopt the new leasing guidance on January 1, 2022 and is currently evaluating the effect ASC 842 will have on its financial statements and related disclosures. ASC 842 provides a number of optional practical expedients in transition. The Company expects to apply the ‘package of practical expedients’ which allow us to not reassess i) whether existing or expired arrangements contain a lease, ii) the lease classification of existing or expired leases, or iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. The Company currently expects the recognition of lease liabilities and right-of-use assets to impact its consolidated balance sheet and lease-related disclosures in the footnotes to the financial statements. The Company does not currently expect ASC 842 to have a material impact to its statements of operations or cash flows. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) , which modifies the measurement of expected credit losses on certain financial instruments. In addition, for available-for-sale debt securities, the standard eliminates the concept of other-than-temporary impairment and requires the recognition of an allowance for credit losses rather than reductions in the amortized cost of the securities. The standard is effective for fiscal year beginning after December 15, 2022, and interim periods beginning after December 15, 2022 and requires a modified-retrospective approach with a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period. Early adoption is permitted. Based on the composition of the Company’s investment portfolio, current market conditions and historical credit loss activity, the adoption of ASU 2016-13 is not expected to have a material impact on its financial position, results of operations or the related disclosures.

Cash and Cash Equivalents, Rest

Cash and Cash Equivalents, Restricted cash, and Marketable Securities	9 Months Ended
	Sep. 30, 2021
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and Cash Equivalents, Restricted cash, and Marketable Securities	Cash and Cash Equivalents, Restricted cash, and Marketable Securities The following table presents the Company’s cash and cash equivalents and restricted cash as of September 30, 2021 and December 31, 2020: September 30, 2021 December 31, 2020 Recurring Fair Cash and cash equivalents: Cash $ 307,646 $ 105,888 Money market funds 21,950,061 4,925,191 Level 1 Fixed income debt securities 14,998,720 — Level 2 Total Cash and cash equivalents 37,256,427 5,031,079 Restricted cash 67,500 67,500 Total cash, cash equivalents, and restricted cash $ 37,323,927 $ 5,098,579 The Company considers all investments in highly liquid financial instruments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents are stated at amortized cost, plus accrued interest, which approximates fair value. Amounts included in restricted cash represent those required as collateral on corporate credit cards. Marketable Securities Marketable securities consist of fixed-income debt securities with an original maturity in excess of ninety days. These investments are classified as available-for-sale and are carried at fair value. Unrealized gains and losses, net of taxes, are reported as a component of other comprehensive income or loss. Realized gains and losses are reported as other income (expense) within the statement of operations. The specific identification method is used to determine the cost basis of the marketable securities sold. There were no realized gains or losses on the sale of marketable securities for the three and nine month ended periods ended September 30, 2021 and 2020. The Company regularly monitors and evaluates the fair value of its investments to identify other-than-temporary declines in value. The Company determined that any decline in fair value of these investments is temporary as the Company does not intend to sell these securities and it is not likely that the Company will be required to sell the securities before the recovery of their amortized cost basis. As of September 30, 2021, the Company’s marketable securities consisted of only fixed-income securities that mature within one year. The amortized cost of these securities amounted to $56.0 million, and the estimated fair value amounted to $56.0 million as of September 30, 2021. The gross unrealized gains and gross unrealized losses on these marketable securities were not material as of September 30, 2021. All marketable securities are measured as Level 2 investments. As of December 31, 2020, the Company did not hold any marketable securities.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company’s financial instruments include cash and cash equivalents, marketable securities, accounts payable, accrued expenses, convertible notes and derivative liabilities. The fair values of the cash and cash equivalents, accounts payable and accrued expenses approximated their carrying values as of September 30, 2021 and December 31, 2020 due to their short-term maturities. The Convertible Notes as discussed in Note 10 contain embedded derivative features that were required to be bifurcated and remeasured to fair value at each reporting period while those instruments were outstanding. The Company accounts for recurring and nonrecurring fair value measurements in accordance with ASC 820, Fair Value Measurements (“ASC 820”). ASC 820 defines fair value, establishes a fair value hierarchy for assets and liabilities measured at fair value, and requires expanded disclosures about fair value measurements. The ASC hierarchy ranks the quality of reliability of inputs, or assumptions, used in the determination of fair value, and requires assets and liabilities carried at fair value to be classified and disclosed in one of the following three categories: Level 1 - Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities. Level 2 - Fair value is determined by using inputs, other than Level 1 quoted prices that are directly and indirectly observable. Inputs can include quoted prices for similar assets and liabilities in active markets or quoted prices for identical assets and liabilities in inactive markets. Related inputs can also include those used in valuation or other pricing models that can be corroborated by observable market data. Level 3 - Fair value is determined by inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant judgments to be made by a reporting entity. In instances where the determination of the fair value measurement is based on inputs from different levels of fair value hierarchy, the fair value measurement will fall within the lowest level input that is significant to the fair value measurement in its entirety. The Company periodically evaluates financial assets and liabilities subject to fair value measurements to determine the appropriate level at which to classify them each reporting period. This determination requires the Company to make judgments as to the significance of inputs used in determining fair value and where such inputs lie within the ASC 820 hierarchy. The Company’s derivative liability related to certain features embedded within the Company’s Convertible Notes as discussed in Note 10. The derivative was accounted for as a liability and remeasured to fair value as of each balance sheet date until the Convertible Notes were converted into shares of common stock upon the Company’s completion of the Initial Public Offering (“IPO”) on February 11, 2021. The related remeasurement adjustments are recognized in the accompanying statements of operations. During the period ended September 30, 2021 and December 31, 2020 the Company did not have any transfers between levels. There were no Level 3 recurring fair value measurements as of September 30, 2021. The following table presents activity related to the Company’s fair value measurements categorized as Level 3 of the valuation hierarchy, valued on a recurring basis: Balance as of December 31, 2020 $ 1,702,359 Fair value of derivative liabilities issued 722,518 Incremental expense related to fair value changes in derivative liabilities (2,424,877) Balance as of September 30, 2021 $ — The following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis: September 30, 2021 December 31, 2020 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets Money market funds $ 21,950,061 $ — $ — $ — $ — $ — Fixed income debt securities — 70,985,075 — — — — $ 21,950,061 $ 70,985,075 $ — $ — $ — $ — Liability Derivative liability — — — — — $ 1,702,359 $ — $ — $ — $ — $ — $ 1,702,359 The fair value of the derivative liability was determined using a binomial lattice model by calculating and comparing the fair value of the Convertible Notes with and without the embedded features. Key inputs into this valuation model are ( l) the probability of various events which result in conversion prior to the maturity of the Convertible Notes; (2) the estimated timing of conversion; (3) time period to maturity; (4) the fair value of the Company’s stock underlying the Convertible Notes within each scenario; (5) the expected volatility of the Company’s stock through the various events resulting in conversion; (6) the risk-adjusted discount rate; and (7) the Company’s stock dividend yield. The recurring Level 3 fair value measurements of the embedded features of the Convertible Notes issued in January 2021 include the following significant unobservable inputs: Unobservable Input Assumptions Probabilities of conversion provisions 5%-50% Estimated timing of conversion (years) 0.13-0.31 Time period to maturity (years) 0.31 Fair value of the Company’s stock $0.45-$0.56 Stock price volatility 76-90% Risk-adjusted discount rate 25.56% Dividend yield 0% Significant changes to these assumptions would result in increases or decreases to the fair value of the derivative liability. There were no Convertible Notes issued after January 2021. Immediately before the conversion of the Convertible Notes on February 11, 2021, the derivative liability was remeasured to fair value which the Company concluded was immaterial. The derivative liability was remeasured to zero. There were no derivative instruments after February 11, 2021.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following at September 30, 2021 and December 31, 2020: September 30, December 31, Prepaid research and development expenses $ 3,774,527 $ 1,894,785 Prepaid maintenance agreements 184,910 144,575 Prepaid insurance 1,223,944 98,421 Prepaid other 201,715 124,929 Deferred financing costs — 952,633 Other current assets 31,479 78,515 Total prepaid expenses and other current assets $ 5,416,575 $ 3,293,858

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment consist of the following at September 30, 2021 and December 31, 2020: September 30, December 31, Laboratory equipment $ 5,615,829 $ 3,801,545 Computer equipment and software 456,063 305,214 Furniture and fixtures 47,877 47,877 Leasehold improvements 214,373 153,965 6,334,142 4,308,601 Less accumulated depreciation and amortization (2,046,888) (1,423,341) Total Property and equipment, net $ 4,287,254 $ 2,885,260 Depreciation and amortization expense was $240,708 and $157,359 for the three months ended September 30, 2021 and 2020, and $635,709 and $448,109 for the nine months ended September 30, 2021 and 2020, respectively. Laboratory equipment includes $0.5 million in equipment received but not yet placed into service.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses A summary of the components of accrued expenses is as follows as of September 30, 2021 and December 31, 2020: September 30, December 31, Accrued research and development costs $ 1,189,543 $ — Accrued professional fees 385,874 135,033 Accrued salaries, benefits and related expenses 2,298,245 1,924,405 Accrued severance — 26,724 Accrued interest — 408,315 Other accrued expenses 57,787 108,550 Total accrued expenses $ 3,931,449 $ 2,603,027

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Maryland Biotechnology Center Grant The Company entered into a Translational Research Award Agreement effective May 23, 2012 with the Department of Business & Economic Development with the State of Maryland, Maryland Biotechnology Center (“MBC”). The mission of MBC is to integrate entrepreneurial strategies to stimulate the transformation of scientific discovery and intellectual assets into capital formation and business development. Under the agreement, MBC provided $200,000 to NexImmune for research on its artificial aAPC for cancer immunotherapy. In 2013, an amendment increased the amount by $125,000 for a total grant of $325,000. This grant was recorded as income in 2012 and 2013, as the Company incurred the expenses which qualified it for the grant. The Company must repay the funds through annual payments calculated at 3% of annual revenues for the preceding year. Payments shall continue for 10 years after the first payment date and may total up to 200% of the total grant amount. The end date of the agreement is defined as January 31, 2024, or when any and all repayments due to MBC have been made. If the Company does not earn any revenue, the grant does not need to be repaid. Through September 30, 2021, no revenue has been recorded, therefore, no payments to MBC are due. Johns Hopkins University Exclusive License Agreement The Company entered into an Exclusive License Agreement with Johns Hopkins University (“JHU”) effective June 2011, which was amended and restated in January 2017, referred to as the A&R JHU License Agreement, under which there are license fees, royalties, and milestone payments. As part of the agreement, the Company acquired a perpetual, exclusive license from JHU covering its invention related to Antigen Specific T cells. In consideration for the Exclusive License Agreement, the Company made an upfront payment of $155,000 and issued 26,918 shares of Common Stock. JHU was also entitled to milestone fees of $75,000 in connection with clinical trial milestones. For the first licensed product or licensed service in the therapeutic field, the Company may be required to pay JHU additional aggregate milestone fees of $1.6 million for clinical and regulatory milestone fees. The Company may be required to pay JHU reduced milestone fees for the second and third licensed products or licensed services in the therapeutic field in connection with clinical and regulatory milestones. In the diagnostic field, the Company may be required to pay JHU aggregate milestone fees of $400,000 for the first licensed product, or licensed service and reduced milestone fees for the second and third licensed products, or licensed services in connection with regulatory and commercial milestones. The Company may be required to pay JHU aggregate milestone fees of $100,000 for commercial milestones for the first licensed product or licensed service in the non-clinical field. In the aggregate, the Company may be required to pay JHU additional milestone fees of up to $4.2 million for all clinical, regulatory and commercial milestones for all licensed products or licensed services in the therapeutic field, the diagnostic field and the non-clinical field. The Company may also be required to pay royalties in the low to upper mid-single digits on net sales of therapeutic products, diagnostic products and non-clinical products. The Company is required to make minimum annual royalty payments of $100,000 to JHU for the remainder of the term of under the A&R JHU License Agreement; the amount of the minimum annual royalty payment started in the low five figures in the first year of the agreement and increased to $100,000 in the third year of the agreement. The Company may also be required to pay JHU a low double digit percentage of any non-royalty sublicense consideration we receive. The Company has incurred $400,000 in cumulative minimum royalties from inception, which royalties offset future royalties per above owed to JHU. Future annual minimum royalties consist of $100,000 due each year during the remaining term of the A&R JHU License Agreement. The Company records milestones, royalties and minimum royalties at the time when payments become probable. During the three and nine months ended September 30, 2021 and 2020, the Company incurred $25,000 and $75,000, respectively, related to minimum royalties owed, included in research and development expenses on the accompanying statement of operations. The Company has accrued royalties of $25,000 as of September 30, 2021. The Company will record a liability when such events become probable of occurring. The Company has not reached any of the milestones or transacted its first commercial sale as of September 30, 2021. Paycheck Protection Program Loan On April 23, 2020, the Company applied for an unsecured $843,619 loan under the Paycheck Protection Program (“PPP Loan”). The Paycheck Protection Program (or “PPP”) was established under the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) and is administered by the U.S. Small Business Administration (“SBA”). On May 1, 2020, the PPP Loan was approved and funded. The Company entered into a promissory note of $843,619, which is recorded within other current liabilities in the accompanying balance sheet. The Company treats the PPP Loan as debt under ASC 470. The use of loan proceeds must be for payroll costs, payment of interest on covered mortgage obligations, rent and utility costs over either an eight-week or 24-week period, at the Company’s option. The PPP Loan had a maturity date of April 23, 2022 and accrued interest at an annual rate of 0.98%. Interest and principal payments were deferred for the first six months of the loan. Thereafter, monthly interest and principal payments were due until the loan is fully satisfied. The promissory note evidencing the PPP Loan contained customary events of default resulting from, among other things, default in the payments. The PPP Loan indebtedness may be forgiven in whole or in part upon request and the Company must provide documentation in accordance with the SBA requirements and the Company must certify that the amounts requested to be forgiven qualify under those requirements. The SBA may approve or deny the Company’s loan forgiveness application, in whole or part. The amount of potential loan forgiveness may be reduced if the Company fails to maintain employee and salary levels during the applicable eight-week or 24-week period following receipt of the loan proceeds. The Company submitted the PPP Loan forgiveness application in March 2021 and received full forgiveness of the $843,619 PPP Loan in July 2021. The Company recognized the $843,619 forgiveness as a gain on extinguishment of debt for the three and nine months ended September 30, 2021. Contingencies From time to time, the Company may be subject to various litigation and related matters arising in the ordinary course of business. The Company records a provision for a liability when it believes that it is both probable that a liability has been

Convertible Notes

Convertible Notes	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Convertible Notes	Convertible Notes In April 2020, the Company entered into Convertible Note Purchase Agreement (“Agreement”) for the sale of up to $15,000,000 of convertible promissory notes with 6% interest rate (“Convertible Notes”). The Agreement specified an initial closing date of April 23, 2020 and allowed additional closings within 90 days of the initial closing. The Convertible Notes were scheduled to mature on April 23, 2021. During the three and nine months ended September 30, 2020, the Company issued convertible notes with a principal amount of $4,380,000 and $10,918,286, respectively. The terms of the Convertible Notes require a mandatory conversion upon certain qualified financing events (“Mandatory Conversion”) and allowed for conversion at the option of the holder upon certain non-qualified financing events (“Optional Conversion 1”). Upon Mandatory Conversion and Optional Conversion 1, the outstanding principal amount and all accrued and unpaid interest would automatically convert into the Company’s preferred stock of the same series issued in such equity financing and will be equal to the number of preferred stock obtained by dividing (a) all principal and accrued but unpaid interest under such Convertible Note by (b) the price per share paid by the other purchasers of the preferred stock sold in such equity financing multiplied by 80%. If the Mandatory Conversion and Optional Conversion 1 did not occur by the maturity date, the outstanding principal amount plus all accrued and unpaid interest would be converted at the option of the holder into Company’s common stock at the price per share obtained by dividing $85 million by the Company’s fully-diluted capitalization (“Optional Conversion 2”). If the Company (i) consummates a change in control or (ii) the Company’s common stock becomes publicly listed on a stock exchange, the outstanding principal amount plus all accrued and unpaid interest would automatically convert into shares of the Company’s most senior series of capital stock outstanding at the time of such change in control or public listing, at a price equal to the lower of (a) 90% of the price per share paid by the purchasers of such stock in such a transaction and (b) the price per share obtained by dividing $125 million by the Company’s fully-diluted capitalization (“Change in Control”). The Agreement was amended in July 2020 to increase the aggregate principal amount to $50,000,000 convertible notes and to allow for additional closings within 150 days of the initial closing date. The Agreement was amended in September 2020 to allow for additional closings within 190 days of the initial closing date. In addition, the provisions of Mandatory Conversion and Optional Conversion 1 were amended to allow for conversion upon an equity financing at a price equal to the lower of (a) 80% of the price per share paid by the purchasers of such stock in such a transaction and (b) the price per share obtained by dividing $125,000,000 by the Company’s fully-diluted capitalization. The Company evaluated the amendments and concluded that the amendments represented a debt modification. In October 2020, the Agreement was further amended to allow additional closings through December 31, 2020, and in January 2021 it was amended again to allow closings through January 31, 2021. In January 2021, the Company issued convertible notes with a principal amount of $9,031,480. The Company evaluated the Convertible Notes and determined that the Mandatory Conversion feature, Optional Conversion 1 feature and Change in Control meet the definition of an embedded derivative liability that is required to be bifurcated from the host instrument and measured at fair value. The fair value of the derivative liability for the convertible notes issued in January 2021 was $722,518 and $803,908 and $879,492 for the convertible notes issued during the three and nine months ended September 30, 2020, respectively. The Company recognized debt issuance costs of $256,212 and a debt discount of $1,982,594 from of the initial value of the derivative liability on Convertible Notes outstanding during the nine months ended September 30, 2021. No amounts were recognized during the three months ended September 30, 2021 as no Convertible Notes were outstanding during the period. The Company recognized debt issuance costs of $93,998 and a debt discount of $185,976, comprising the additional value of the derivative liability discount of $185,976 and the beneficial conversion feature of $0 on Convertible Notes outstanding during the three months ended September 30, 2020. The Company recognized debt issuance costs of $183,892 and a debt discount of $1,547,880, comprising the total value of the derivative liability discount of $482,248 and the beneficial conversion feature of $1,065,632 on Convertible Notes outstanding during the nine months ended September 30, 2020. The debt issuance costs and debt discount are amortized over the term of the Convertible Notes using the effective interest method. Amortization expense for the three and nine months ended September 30, 2021 was $0 and $613,770, respectively. Amortization expense for the three and nine months ended September 30, 2020 was $414,622 and $555,450, respectively. The debt issuance costs and debt discount amortization expense is included in interest expense in the accompanying statements of operations. The interest expense at 6% of the Convertible Notes’ principal amount for the three and nine months ended September 30, 2021 was $0 and $217,593, respectively. The interest expense at 6% of the Convertible Notes’ principal amount for the three and nine months ended September 30, 2020 was $140,818 and $183,182, respectively. The effective interest rate during the three and nine months ended September 30, 2021 and 2020 was 25% and 27% respectively. The unamortized debt issuance costs and debt discount on the Convertible Notes as of September 30, 2020 were $134,238 and $1,042,090, respectively and as of December 31, 2020, were $116,636 and $2,383,986, respectively. The Company completed an IPO on February 11, 2021, which triggered the mandatory conversion of all the outstanding Convertible Notes plus accrued interest into 3,669,010 shares of common stock (Note 10). Upon conversion of the Convertible Notes, the outstanding Convertible notes principal plus accrued interest thereon, net of unamortized debt discounts totaling $30,252,056 was reclassified to stockholders’ equity (deficit).

Series A Redeemable Convertible

Series A Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit)	9 Months Ended
	Sep. 30, 2021
Redeemable Convertible Preferred Stock And Stockholders Equity Disclosure [Abstract]
Series A Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit)	Series A Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) Issuances of Common Stock On February 11, 2021, the Company completed its IPO, pursuant to which it issued and sold 7,441,650 shares of its common stock at a public offering price of $17.00 per share, resulting in net proceeds of $114,551,315, after deducting underwriting discounts and commissions and other offering expenses. Upon the closing of the IPO, all of the 175,137,398 outstanding shares of the Company’s Redeemable Convertible Preferred Stock automatically converted into 10,144,052 shares of common stock after giving effect to the reverse stock split, and all of the outstanding convertible debt and accrued but unpaid interest thereon of $31,272,224 converted to 3,669,010 shares of common stock. Upon completion of the offering on February 11, 2021, the Company’s authorized capital stock consists of 250,000,000 shares of common stock, par value $0.0001 per share, and 10,000,000 shares of preferred stock, par value $0.0001 per share, all of which shares of preferred stock are undesignated. In January 2021, 145,000 warrants were exercised at an exercise price of $0.01 and 145,000 shares of Series A redeemable convertible stock were issued and then converted into common stock upon the closing of the IPO. The remaining outstanding warrants outstanding as of December 31, 2020 were exercised and settled in January 2021 with 2,896 shares of common stock issued in a cashless exercise.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation During January 2017, the Company adopted the 2017 Equity Incentive Plan (“2017 Plan”), which provides for granting of restricted stock, options to purchase shares of common stock and other awards to employees, directors and consultants. In March 2017, the Company amended the 2017 Plan to increase the number of available shares to 660,838. In September 2018, the Company adopted the 2018 Equity Incentive Plan (“2018 Plan”) which provides for granting of restricted stock, options to purchase shares of common stock, and other awards to employees, directors and consultants, and reserved 1,741,770 shares for this purpose. The 2018 Plan was amended in July 2018 to increase the number of available shares to 1,809,143. In February 2021, the Company adopted the 2021 Equity Incentive Plan (“2021 Plan”) and reserved 2,757,556 shares under the plan. No further shares will be issued under the 2017 and 2018 plans. There are 1,256,043 shares available for issuance under the 2021 plan. The number of options to be granted under the 2021 Plan, the option exercise prices, and other terms of the options are determined by the Board of Directors in accordance with the terms of the 2021 Plan Generally, stock options are granted at fair value, become exercisable over a period of one Stock-based compensation expense was recorded in the following financial statement line items within the statement of operations for the period ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development expenses $ 719,768 $ 62,383 $ 1,572,882 $ 228,833 General and administrative expenses 908,662 222,075 2,736,474 714,377 Total stock-based compensation expense $ 1,628,430 $ 284,458 $ 4,309,356 $ 943,210 The following is a summary of option activity under the Company’s Stock Option Plans: Stock Options Weighted Weighted Aggregate Outstanding as of January 1, 2021 2,233,185 $ 3.52 Granted 1,503,013 16.78 Exercised (197,041) 3.37 Cancelled (1,699) 4.78 Forfeited (196,831) 4.94 Outstanding as of September 30, 2021 3,340,627 $ 9.41 7.9 22.0 Vested or expected to vest as of September 30, 2021 3,340,627 $ 9.41 7.9 22.0 Exercisable as of September 30, 2021 1,672,745 $ 3.35 6.5 19.8 Shares unvested as of September 30, 2021 1,667,862 $ 15.49 9.3 2.2 The weighted average fair value of the options granted during the nine months ended September 30, 2021 and 2020 was $11.40 and $4.01, respectively. The options were valued using the Black-Scholes option-pricing model for the nine months ended September 30, 2021 and 2020 with the following assumptions: 2021 2020 Expected volatility 79.5% to 81.1% 100 % Risk-free interest rate 0.6% to 1.1% 0.7% to 0.74 % Expected dividend yield 0 % 0 % Expected term 5.5 to 6.0 years 5.3 to 6.0 years The total fair value of stock options vested during the nine months ended September 30, 2021 and 2020 was approximately $1.2 million, and $0.7 million, respectively. The intrinsic value of stock options exercised for the nine months ended September 30, 2021 and 2020 was approximately $2.0 million and $0, respectively.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common StockholdersBasic net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common stock and common stock equivalents outstanding for the period. The Company adjusts net loss to arrive at the net loss attributable to common stockholders to reflect the amount of dividends accumulated during the period on the Company’s redeemable convertible preferred stock. Such dividends are only payable if and when declared by the Board of Directors. The treasury stock method is used to determine the dilutive effect of the Company’s stock option grants and warrants and the if-converted method is used to determine the dilutive effect of the Company’s redeemable convertible preferred stock and Convertible Notes. For the three and nine months ended September 30, 2021 and 2020, the Company had a net loss attributable to common stockholders, and as such, all outstanding stock options and shares of redeemable convertible preferred stock were excluded from the calculation of diluted loss per share. Under the if-converted method, convertible instruments that are in the money, are assumed to have been converted as of the beginning of the period or when issued, if later. Additionally, the effects of any interest expense and changes in fair value of bifurcated derivatives is added back to the numerator of the diluted net loss per share calculation if the conversion of the Convertible Notes is dilutive. The following table sets forth the computation of basic and diluted earnings per share for the three and nine months ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ (14,647,112) $ (8,608,735) $ (35,375,910) $ (21,854,768) Accumulated dividends on Redeemable Convertible Preferred Stock — (824,781) (377,562) (2,456,413) Net loss attributable to common stockholders $ (14,647,112) $ (9,433,516) $ (35,753,472) $ (24,311,181) Basic and diluted net loss per common share $ (0.65) $ (7.52) $ (1.85) $ (19.38) Basic and diluted weighted average common shares outstanding 22,653,410 1,254,808 19,335,170 1,254,724 The following potentially dilutive securities outstanding at September 30, 2021 and 2020 have been excluded from the computation of diluted weighted average common shares outstanding, as the effect would be anti-dilutive: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Stock options 3,340,627 2,237,420 3,340,627 2,237,420 Redeemable convertible preferred stock — 10,135,735 1,560,635 10,135,735 Convertible debt — 1,542,484 679,404 674,746 Warrants — 14,480 201 14,480 Total 3,340,627 13,930,119 5,580,867 13,062,381 Shares of redeemable convertible preferred stock also participate in dividends with shares of common stock (if and when declared) and therefore are deemed participating securities. The holders of redeemable convertible preferred stock do not contractually share in losses and therefore no additional net loss per share has been disclosed under the two-class method.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company has not recorded any tax provision or benefit for the three and nine months ended September 30, 2021 and 2020. The Company has provided a valuation allowance for the full amount of its net deferred tax assets since realization of any future benefit from deductible temporary differences, net operating loss carryforwards, and research and development credits is not more-likely-than-not to be realized at September 30, 2021 and December 31, 2021. The effective tax rate for the three and nine months ended September 30, 2021 and 2020 is 0%. The Company has not recorded any accruals related to uncertain tax positions as of September 30, 2021 and December 31, 2020. Income tax returns are filed in federal and state jurisdictions and generally subject to a three-year statute of limitations. The years that are subject to examination by tax authorities are tax years 2017 through 2020, although tax years dating back to 2015 remain open to the tax attribute amounts carried forward for future use.

Employee Benefit Plan

Employee Benefit Plan	9 Months Ended
	Sep. 30, 2021
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit PlanThe Company has a defined contribution plan under the Internal Revenue Code Section 401(k). The plan covers all employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. The Company may contribute a matching contribution at its discretion. During the three and nine months ended September 30, 2021, the Company made contributions of $54,506 and $184,476, respectively, to the plan. During the three and nine months ended September 30, 2020, the Company made contributions of $37,071, and $125,553, respectively, to the plan.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited financial statements were prepared in accordance with the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, they do not include all of the information required by U.S. generally accepted accounting principles (“GAAP”) for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). These financial statements should be read in conjunction with our audited financial statements and the accompanying notes to our financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the SEC on March 31, 2021. In management’s opinion, the accompanying financial statements contain all adjustments, including normal, recurring adjustments, necessary to fairly present our financial position as of September 30, 2021 and December 31, 2020, and our statements of operations and comprehensive income, statements of changes in redeemable convertible preferred stock and stockholders’ equity (deficit), and statement of cash flows for the three and nine month periods ended September 30, 2021 and 2020. Interim results are not necessarily indicative of results for an entire year.
Recent Accounting Standards and Pronouncements	Recent accounting standards and pronouncements Recently Adopted In August 2020, the FASB issued ASU 2020-06, an update to ASC Topic 470, Subtopic - 20, Debt - Debt with Conversion and Other Options, and ASC Topic 815, Subtopic - 4, Derivatives and Hedging - Contracts in Entity’s Own Equity . ASU 2020-06 simplifies the guidance for certain financial instruments with characteristics of liability and equity, including convertible instruments and contracts on an entity’s own equity by reducing the number of accounting models for convertible instruments and amends guidance in ASC Topic 260, Earnings Per Share, relating to the computation of earnings per share for convertible instruments and contracts on an entity’s own equity. ASU 2020-06 is effective for interim and annual reporting periods in fiscal years that begin after December 15, 2021, with early adoption permitted for fiscal years that begin after December 15, 2020. The Company early adopted this standard effective January 1, 2021 using the modified retrospective method. Under this standard, only conversion features embedded in the debt instrument that are accounted for as derivatives in accordance with ASC 815 or under the substantial premium model in ASC 470, require separate accounting. Prior to the adoption of this standard, the Company had recorded a beneficial conversion feature as a discount to convertible notes issued. Upon adoption of this standard, the beneficial conversion feature is no longer separately accounted. As a result of applying the modified retrospective method, the Company recognized a transition adjustment of $0.7 million recorded in accumulated deficit, a reduction of additional paid-in capital of $2.2 million and an increase to the carrying value of the convertible notes of $1.5 million on January 1, 2021. Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (ASC 842). The guidance amends the existing accounting standards for lease accounting, including requirements for lessees to recognize assets and liabilities related to long-term leases on the balance sheet and expanding disclosure requirements regarding leasing arrangements. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. In July 2018, the FASB issued additional guidance, which offers a transition option to entities adopting ASC 842 in which entities can elect to apply the new guidance using a modified retrospective approach at the beginning of the year in which the new lease standard is adopted.. The Company currently expects to utilize this transition option whereby financial information for prior periods presented before the ASC 842 effective date will not be updated. In November 2019, the FASB issued ASU 2019-10 deferring the effective date for private entities for fiscal years beginning after December 15, 2020 and interim periods within fiscal years beginning after December 15, 2021. In June 2020, the FASB issued ASU 2020-05 which further defers the effective date for private entities for fiscal years beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022. The Company will adopt the new leasing guidance on January 1, 2022 and is currently evaluating the effect ASC 842 will have on its financial statements and related disclosures. ASC 842 provides a number of optional practical expedients in transition. The Company expects to apply the ‘package of practical expedients’ which allow us to not reassess i) whether existing or expired arrangements contain a lease, ii) the lease classification of existing or expired leases, or iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. The Company currently expects the recognition of lease liabilities and right-of-use assets to impact its consolidated balance sheet and lease-related disclosures in the footnotes to the financial statements. The Company does not currently expect ASC 842 to have a material impact to its statements of operations or cash flows. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) , which modifies the measurement of expected credit losses on certain financial instruments. In addition, for available-for-sale debt securities, the standard eliminates the concept of other-than-temporary impairment and requires the recognition of an allowance for credit losses rather than reductions in the amortized cost of the securities. The standard is effective for fiscal year beginning after December 15, 2022, and interim periods beginning after December 15, 2022 and requires a modified-retrospective approach with a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period. Early adoption is permitted. Based on the composition of the Company’s investment portfolio, current market conditions and historical credit loss activity, the adoption of ASU 2016-13 is not expected to have a material impact on its financial position, results of operations or the related disclosures.
Fair Value Measurement	Fair Value Measurements The Company’s financial instruments include cash and cash equivalents, marketable securities, accounts payable, accrued expenses, convertible notes and derivative liabilities. The fair values of the cash and cash equivalents, accounts payable and accrued expenses approximated their carrying values as of September 30, 2021 and December 31, 2020 due to their short-term maturities. The Convertible Notes as discussed in Note 10 contain embedded derivative features that were required to be bifurcated and remeasured to fair value at each reporting period while those instruments were outstanding. The Company accounts for recurring and nonrecurring fair value measurements in accordance with ASC 820, Fair Value Measurements (“ASC 820”). ASC 820 defines fair value, establishes a fair value hierarchy for assets and liabilities measured at fair value, and requires expanded disclosures about fair value measurements. The ASC hierarchy ranks the quality of reliability of inputs, or assumptions, used in the determination of fair value, and requires assets and liabilities carried at fair value to be classified and disclosed in one of the following three categories: Level 1 - Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities. Level 2 - Fair value is determined by using inputs, other than Level 1 quoted prices that are directly and indirectly observable. Inputs can include quoted prices for similar assets and liabilities in active markets or quoted prices for identical assets and liabilities in inactive markets. Related inputs can also include those used in valuation or other pricing models that can be corroborated by observable market data. Level 3 - Fair value is determined by inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant judgments to be made by a reporting entity. In instances where the determination of the fair value measurement is based on inputs from different levels of fair value hierarchy, the fair value measurement will fall within the lowest level input that is significant to the fair value measurement in its entirety. The Company periodically evaluates financial assets and liabilities subject to fair value measurements to determine the appropriate level at which to classify them each reporting period. This determination requires the Company to make judgments as to the significance of inputs used in determining fair value and where such inputs lie within the ASC 820 hierarchy. The Company’s derivative liability related to certain features embedded within the Company’s Convertible Notes as discussed in Note 10. The derivative was accounted for as a liability and remeasured to fair value as of each balance sheet date until the Convertible Notes were converted into shares of common stock upon the Company’s completion of the Initial Public Offering (“IPO”) on February 11, 2021. The related remeasurement adjustments are recognized in the accompanying statements of operations.
Earnings Per Share	Net Loss Per Share Attributable to Common StockholdersBasic net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common stock and common stock equivalents outstanding for the period. The Company adjusts net loss to arrive at the net loss attributable to common stockholders to reflect the amount of dividends accumulated during the period on the Company’s redeemable convertible preferred stock. Such dividends are only payable if and when declared by the Board of Directors. The treasury stock method is used to determine the dilutive effect of the Company’s stock option grants and warrants and the if-converted method is used to determine the dilutive effect of the Company’s redeemable convertible preferred stock and Convertible Notes.

Cash and Cash Equivalents, Re_2

Cash and Cash Equivalents, Restricted cash, and Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2021
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Summary of reconciliation of cash, cash equivalents, and restricted cash	The following table presents the Company’s cash and cash equivalents and restricted cash as of September 30, 2021 and December 31, 2020: September 30, 2021 December 31, 2020 Recurring Fair Cash and cash equivalents: Cash $ 307,646 $ 105,888 Money market funds 21,950,061 4,925,191 Level 1 Fixed income debt securities 14,998,720 — Level 2 Total Cash and cash equivalents 37,256,427 5,031,079 Restricted cash 67,500 67,500 Total cash, cash equivalents, and restricted cash $ 37,323,927 $ 5,098,579

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Summary of fair value measurements categorized as Level 3	The following table presents activity related to the Company’s fair value measurements categorized as Level 3 of the valuation hierarchy, valued on a recurring basis: Balance as of December 31, 2020 $ 1,702,359 Fair value of derivative liabilities issued 722,518 Incremental expense related to fair value changes in derivative liabilities (2,424,877) Balance as of September 30, 2021 $ —
Schedule of fair value assets and liabilities measured on recurring basis	The following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis: September 30, 2021 December 31, 2020 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets Money market funds $ 21,950,061 $ — $ — $ — $ — $ — Fixed income debt securities — 70,985,075 — — — — $ 21,950,061 $ 70,985,075 $ — $ — $ — $ — Liability Derivative liability — — — — — $ 1,702,359 $ — $ — $ — $ — $ — $ 1,702,359
Summary of fair value measurements of the convertible notes	The recurring Level 3 fair value measurements of the embedded features of the Convertible Notes issued in January 2021 include the following significant unobservable inputs: Unobservable Input Assumptions Probabilities of conversion provisions 5%-50% Estimated timing of conversion (years) 0.13-0.31 Time period to maturity (years) 0.31 Fair value of the Company’s stock $0.45-$0.56 Stock price volatility 76-90% Risk-adjusted discount rate 25.56% Dividend yield 0%

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of prepaid expenses and other current assets	Prepaid expenses and other current assets consist of the following at September 30, 2021 and December 31, 2020: September 30, December 31, Prepaid research and development expenses $ 3,774,527 $ 1,894,785 Prepaid maintenance agreements 184,910 144,575 Prepaid insurance 1,223,944 98,421 Prepaid other 201,715 124,929 Deferred financing costs — 952,633 Other current assets 31,479 78,515 Total prepaid expenses and other current assets $ 5,416,575 $ 3,293,858

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Summary of property and equipment	Property and equipment consist of the following at September 30, 2021 and December 31, 2020: September 30, December 31, Laboratory equipment $ 5,615,829 $ 3,801,545 Computer equipment and software 456,063 305,214 Furniture and fixtures 47,877 47,877 Leasehold improvements 214,373 153,965 6,334,142 4,308,601 Less accumulated depreciation and amortization (2,046,888) (1,423,341) Total Property and equipment, net $ 4,287,254 $ 2,885,260

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Summary of the components of accrued expenses	A summary of the components of accrued expenses is as follows as of September 30, 2021 and December 31, 2020: September 30, December 31, Accrued research and development costs $ 1,189,543 $ — Accrued professional fees 385,874 135,033 Accrued salaries, benefits and related expenses 2,298,245 1,924,405 Accrued severance — 26,724 Accrued interest — 408,315 Other accrued expenses 57,787 108,550 Total accrued expenses $ 3,931,449 $ 2,603,027

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Summary of stock-based compensation expense	Stock-based compensation expense was recorded in the following financial statement line items within the statement of operations for the period ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development expenses $ 719,768 $ 62,383 $ 1,572,882 $ 228,833 General and administrative expenses 908,662 222,075 2,736,474 714,377 Total stock-based compensation expense $ 1,628,430 $ 284,458 $ 4,309,356 $ 943,210
Summary of option activity	The following is a summary of option activity under the Company’s Stock Option Plans: Stock Options Weighted Weighted Aggregate Outstanding as of January 1, 2021 2,233,185 $ 3.52 Granted 1,503,013 16.78 Exercised (197,041) 3.37 Cancelled (1,699) 4.78 Forfeited (196,831) 4.94 Outstanding as of September 30, 2021 3,340,627 $ 9.41 7.9 22.0 Vested or expected to vest as of September 30, 2021 3,340,627 $ 9.41 7.9 22.0 Exercisable as of September 30, 2021 1,672,745 $ 3.35 6.5 19.8 Shares unvested as of September 30, 2021 1,667,862 $ 15.49 9.3 2.2
Summary of black-scholes option pricing model	The options were valued using the Black-Scholes option-pricing model for the nine months ended September 30, 2021 and 2020 with the following assumptions: 2021 2020 Expected volatility 79.5% to 81.1% 100 % Risk-free interest rate 0.6% to 1.1% 0.7% to 0.74 % Expected dividend yield 0 % 0 % Expected term 5.5 to 6.0 years 5.3 to 6.0 years

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Summary of basic and diluted earnings per share	The following table sets forth the computation of basic and diluted earnings per share for the three and nine months ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ (14,647,112) $ (8,608,735) $ (35,375,910) $ (21,854,768) Accumulated dividends on Redeemable Convertible Preferred Stock — (824,781) (377,562) (2,456,413) Net loss attributable to common stockholders $ (14,647,112) $ (9,433,516) $ (35,753,472) $ (24,311,181) Basic and diluted net loss per common share $ (0.65) $ (7.52) $ (1.85) $ (19.38) Basic and diluted weighted average common shares outstanding 22,653,410 1,254,808 19,335,170 1,254,724
Summary of antidilutive securities outstanding	The following potentially dilutive securities outstanding at September 30, 2021 and 2020 have been excluded from the computation of diluted weighted average common shares outstanding, as the effect would be anti-dilutive: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Stock options 3,340,627 2,237,420 3,340,627 2,237,420 Redeemable convertible preferred stock — 10,135,735 1,560,635 10,135,735 Convertible debt — 1,542,484 679,404 674,746 Warrants — 14,480 201 14,480 Total 3,340,627 13,930,119 5,580,867 13,062,381

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail) - USD ($)	Sep. 30, 2021	Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transition adjustment recorded in accumulated deficit	$ 97,109,160	$ 109,909,420		$ (69,374,941)	$ (62,855,162)	$ (54,562,092)	$ (43,009,568)
Convertible notes	0			11,793,397
Cumulative effect of adoption of accounting standard
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transition adjustment recorded in accumulated deficit				(1,537,274)
Convertible notes			$ 1,500,000
Accumulated Deficit
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transition adjustment recorded in accumulated deficit	(112,217,857)	(97,570,745)		(77,582,005)	(69,570,776)	(60,962,041)	(47,716,008)
Accumulated Deficit | Cumulative effect of adoption of accounting standard
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transition adjustment recorded in accumulated deficit			700,000	740,058
Additional Paid-in Capital
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transition adjustment recorded in accumulated deficit	$ 209,324,044	$ 207,480,819		8,206,938	$ 6,715,488	$ 6,399,823	$ 4,705,808
Additional Paid-in Capital | Cumulative effect of adoption of accounting standard
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transition adjustment recorded in accumulated deficit			$ (2,200,000)	$ (2,277,332)

Cash and Cash Equivalents, Re_3

Cash and Cash Equivalents, Restricted cash, and Marketable Securities - Summary of Reconciliation of Cash, Cash Equivalents And Restricted Cash (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Line Items]
Cash	$ 307,646	$ 105,888
Cash and cash equivalents	37,256,427	5,031,079
Cash, cash equivalents, and restricted cash	37,323,927	5,098,579
Money market funds | Level 1
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	21,950,061	4,925,191
Fixed income debt securities | Level 2
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	14,998,720	0
Restricted cash
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	$ 67,500	$ 67,500

Cash and Cash Equivalents, Re_4

Cash and Cash Equivalents, Restricted cash, and Marketable Securities - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Line items [Line Items]
Realized gains or losses on the sale of marketable securities	$ 0	$ 0	$ 0	$ 0
Amortized cost of marketable securities	56,000,000		56,000,000
Estimated fair value of marketable securities	$ 56,000,000		$ 56,000,000
Investment positions in marketable securities					$ 0
Fixed income debt securities
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Line items [Line Items]
Marketable securities maturity date	90 days		90 days
Marketable securities maturity year			1 year

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value Measurements Categorized As Level 3 (Detail) - Embedded Derivative Financial Instruments - Recurring basis	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance as of December 31, 2020	$ 1,702,359
Fair value of derivative liabilities issued	722,518
Incremental expense related to fair value changes in derivative liabilities	(2,424,877)
Balance as of September 30, 2021	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Liability
Derivative liability	$ 0
Level 1 | Recurring basis
Assets
Total assets	21,950,061	$ 0
Liability
Total liabilities	0	0
Level 1 | Recurring basis | Derivative liability
Liability
Derivative liability	0	0
Level 1 | Money market funds | Recurring basis
Assets
Money market funds	21,950,061	0
Level 1 | Fixed income debt securities | Recurring basis
Assets
Fixed income debt securities	0	0
Level 2 | Recurring basis
Assets
Total assets	70,985,075	0
Liability
Total liabilities	0	0
Level 2 | Recurring basis | Derivative liability
Liability
Derivative liability	0	0
Level 2 | Money market funds | Recurring basis
Assets
Money market funds	0	0
Level 2 | Fixed income debt securities | Recurring basis
Assets
Fixed income debt securities	70,985,075	0
Level 3 | Recurring basis
Assets
Total assets	0	0
Liability
Total liabilities	0	1,702,359
Level 3 | Recurring basis | Derivative liability
Liability
Derivative liability	0	1,702,359
Level 3 | Money market funds | Recurring basis
Assets
Money market funds	0	0
Level 3 | Fixed income debt securities | Recurring basis
Assets
Fixed income debt securities	$ 0	$ 0

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Fair Value Measurements of the Convertible Notes (Detail) - Embedded Derivative Financial Instruments - Level 3	Feb. 11, 2021$ / sharesyr
Probabilities of conversion provisions | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.50
Probabilities of conversion provisions | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.05
Estimated timing of conversion (years) | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.31
Estimated timing of conversion (years) | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.13
Time period to maturity (years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.31
Fair value of the company's stock (in dollars per share) | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input | $ / shares	0.56
Fair value of the company's stock (in dollars per share) | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input | $ / shares	0.45
Stock price volatility | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.90
Stock price volatility | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.76
Risk-adjusted discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0.2556
Dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Input	0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	Sep. 30, 2021USD ($)
Fair Value Disclosures [Abstract]
Derivative liability	$ 0
Derivative instruments	$ 0

Prepaid Expenses And Other Cu_3

Prepaid Expenses And Other Current Assets - Summary of Prepaid Expenses And Other Current Assets (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid research and development expenses	$ 3,774,527	$ 1,894,785
Prepaid maintenance agreements	184,910	144,575
Prepaid insurance	1,223,944	98,421
Prepaid other	201,715	124,929
Deferred financing costs	0	952,633
Other current assets	31,479	78,515
Total prepaid expenses and other current assets	$ 5,416,575	$ 3,293,858

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 240,708	$ 157,359	$ 635,709	$ 448,109
Property plant and equipment gross	6,334,142		6,334,142		$ 4,308,601
Laboratory equipment received but not placed into service
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	$ 500,000		$ 500,000

Property and Equipment - Summar

Property and Equipment - Summary of Property And Equipment (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	$ 6,334,142	$ 4,308,601
Less accumulated depreciation and amortization	(2,046,888)	(1,423,341)
Total Property and equipment, net	4,287,254	2,885,260
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	5,615,829	3,801,545
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	456,063	305,214
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	47,877	47,877
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	$ 214,373	$ 153,965

Accrued Expenses - Summary of C

Accrued Expenses - Summary of Components of Accrued Expenses (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued research and development costs	$ 1,189,543	$ 0
Accrued professional fees	385,874	135,033
Accrued salaries, benefits and related expenses	2,298,245	1,924,405
Accrued severance	0	26,724
Accrued interest	0	408,315
Other accrued expenses	57,787	108,550
Accrued expenses	$ 3,931,449	$ 2,603,027

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	May 01, 2020	Jan. 01, 2017	May 23, 2013	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Apr. 23, 2020	May 23, 2012
Research and development arrangement contract to perform for others compensation earned			$ 125,000
Accrued royalties				$ 25,000		$ 25,000
Deferred interest and principal payments	6 months
Gain on extinguishment of debt from PPP loan forgiveness						843,619	$ 0
Loss contingency accrual				0		0		$ 0
Other Current Liabilities
Notes payable, current	$ 843,619
Paycheck Protection Program Loan
PPP loan face amount									$ 843,619
PPP loan interest rate	0.98%
Gain on extinguishment of debt from PPP loan forgiveness				843,619		843,619
Research and development expenses | Minimum
Royalty expense				25,000	$ 75,000	25,000	$ 75,000
Maryland Biotechnology Center | Translational Research Award Agreement
Research and development arrangement contract to perform for others liability			$ 325,000	0		0				$ 200,000
Research and development arrangement annual payment percentage			3.00%
Research and development arrangement contractual payment period			10 years
Research and development arrangement contractual payment percentage			200.00%
Revenue from contract with customer, including assessed tax						0
Johns Hopkins University | Exclusive License Agreement
Upfront payment		$ 155,000
Stock issued during period for services (in shares)		26,918
Milestone fees		$ 4,200,000
Minimum annual royalty payments						100,000
Cumulative minimum royalties				$ 400,000		$ 400,000
Johns Hopkins University | Exclusive License Agreement | Clinical Trial Milestones
Milestone fees		75,000
Johns Hopkins University | Exclusive License Agreement | Therapeutic Field
Milestone fees		1,600,000
Johns Hopkins University | Exclusive License Agreement | Regulatory and Commercial Milestones
Milestone fees		400,000
Johns Hopkins University | Exclusive License Agreement | Non-clinical field
Milestone fees		$ 100,000

Convertible Notes - Additional

Convertible Notes - Additional Information (Detail) - USD ($)	Feb. 11, 2021	Jan. 31, 2021	Sep. 30, 2020	Jul. 31, 2020	Apr. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Derivative liability						$ 0		$ 0
Amortization of debt issuance costs and discounts						$ 0	$ 414,622	$ 613,770	$ 555,450
Convertible Debt
Debt Instrument [Line Items]
PPP loan face amount		$ 9,031,480			$ 15,000,000
PPP loan interest rate			6.00%		6.00%	6.00%	6.00%	6.00%	6.00%
Additional closing period (in days)			190 days	150 days	90 days
Proceeds from issuance of convertible debt							$ 4,380,000		$ 10,918,286
Convertible note price percentage					80.00%
Convertible note fully diluted capitalization					$ 85,000,000
Convertible note redemption price, percentage of principal amount redeemed			80.00%		90.00%
Convertible note redemption amount			$ 125,000,000	$ 50,000,000	$ 125,000,000		125,000,000		125,000,000
Fair value of derivative liability of convertible notes		$ 722,518					803,908		879,492
Debt issuance costs						$ 0	93,998	$ 256,212	183,892
Debt discount						0	185,976	1,982,594	1,547,880
Long term debt						0		0
Amortization of derivative liability discount							185,976		482,248
Beneficial conversion feature	$ 31,272,224						0		1,065,632
Interest expense						$ 0	$ 140,818	$ 217,593	$ 183,182
Effective interest rate during the period			27.00%			25.00%	27.00%	25.00%	27.00%
Unamortized debt issuance costs			$ 134,238				$ 134,238		$ 134,238	$ 116,636
Debt discount on convertible notes			$ 1,042,090				$ 1,042,090		$ 1,042,090	$ 2,383,986
Convertible notes outstanding converted into common stock (in shares)	3,669,010
Convertible notes outstanding, net of unamortized discounts, reclassified to stockholders' equity	$ 30,252,056

Series A Redeemable Convertib_2

Series A Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - Additional Information (Detail) - USD ($)	Feb. 11, 2021	Jan. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Class of Stock [Line Items]
Proceeds From Issuance Of IPO				$ 114,721,518	$ 0
Authorized common stock (in shares)	250,000,000			250,000,000		250,000,000
Common stock, par value (in dollars per share)	$ 0.0001			$ 0.0001		$ 0.0001
Authorized preferred stock (in shares)	10,000,000
Preferred stock, par value (in dollars per share)	$ 0.0001
Warrants exercised (in shares)		2,896
Exercise price of warrants (in dollars per share)		$ 0.01
Convertible Debt
Class of Stock [Line Items]
Beneficial conversion feature	$ 31,272,224		$ 0		$ 1,065,632
Convertible notes outstanding converted into common stock (in shares)	3,669,010
Common Class A | IPO
Class of Stock [Line Items]
Stock issued during period (in shares)	7,441,650
Public offering price (in dollars per share)	$ 17
Proceeds From Issuance Of IPO	$ 114,551,315
Redeemable convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock outstanding (in shares)	175,137,398
Converted common stock (in shares)	10,144,052
Series A Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Converted common stock (in shares)		145,000
Warrants exercised (in shares)		145,000
Issuance of Series A redeemable preferred stock upon exercise of warrants (in shares)		145,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended	9 Months Ended
	Feb. 28, 2021	Sep. 30, 2021	Sep. 30, 2020	Jul. 31, 2018	Jun. 30, 2018	Mar. 01, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares reserved (in shares)	2,757,556				1,741,770
Shares available for issuance (in shares)	1,256,043
Weighted average fair value of the options granted		$ 11.40	$ 4.01
Fair value of stock options vested		$ 1,200,000	$ 700,000
Intrinsic value of stock options exercised		2,000,000	$ 0
Unrecognized compensation expense		$ 14,200,000
Stock options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized compensation expense period for recognition		2 years 8 months 12 days
The 2017 Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares reserved (in shares)						660,838
The 2018 Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares reserved (in shares)				1,809,143
The 2021 Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award expiration period	10 years
The 2021 Plan | Minimum
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period	1 year
The 2021 Plan | Maximum
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period	4 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Based Compensation Expense (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 1,628,430	$ 284,458	$ 4,309,356	$ 943,210
Research and development expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	719,768	62,383	1,572,882	228,833
General and administrative expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 908,662	$ 222,075	$ 2,736,474	$ 714,377

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Option Activity (Detail) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2021
Number of Shares
Outstanding as of beginning of period (in shares)	2,233,185
Granted (in shares)	1,503,013
Exercised (in shares)	(197,041)
Cancelled (in shares)	(1,699)
Forfeited (in shares)	(196,831)
Outstanding as of end of period (in shares)	3,340,627
Vested or expected to vest by period end (in shares)	3,340,627
Exercisable as of period end (in shares)	1,672,745
Shares unvested as of period end (in shares)	1,667,862
Weighted Average Exercise Price
Outstanding as of beginning of period (in dollars per share)	$ 3.52
Granted (in dollars per share)	16.78
Exercised (in dollars per share)	3.37
Cancelled (in dollars per share)	4.78
Forfeited (in dollars per share)	4.94
Outstanding as of end of period (in dollars per share)	9.41
Vested or expected to vest as of end of period (in dollars per share)	9.41
Exercisable as of end of period (in dollars per share)	3.35
Shares unvested as of end of period (in dollars per share)	$ 15.49
Weighted Average Remaining Contractual Term (years)
Outstanding as of end of period (in years)	7 years 10 months 24 days
Vested or expected to vest as of end of period (in years)	7 years 10 months 24 days
Exercisable as of end of period (in years)	6 years 6 months
Shares unvested as of end of period (in years)	9 years 3 months 18 days
Aggregate Intrinsic Value (millions)
Outstanding as of September 30, 2021	$ 22
Vested or expected to vest as of September 30, 2021	22
Exercisable as of September 30, 2021	19.8
Shares unvested as of September 30, 2021	$ 2.2

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Black-Scholes Option Pricing Model (Detail)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Expected volatility	79.50%
Expected volatility	81.10%
Expected volatility		100.00%
Risk-free interest rate	0.60%	0.70%
Risk-free interest rate	1.10%	0.74%
Expected dividend yield	0.00%	0.00%
Minimum
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Expected term	5 years 6 months	5 years 3 months 18 days
Maximum
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Expected term	6 years	6 years

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Summary of Basic and Diluted Earnings Per Share (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (14,647,112)	$ (8,608,735)	$ (35,375,910)	$ (21,854,768)
Accumulated dividends on Redeemable Convertible Preferred Stock	0	(824,781)	(377,562)	(2,456,413)
Net loss attributable to common stockholders	$ (14,647,112)	$ (9,433,516)	$ (35,753,472)	$ (24,311,181)
Basic net loss per common share (in dollars per share)	$ (0.65)	$ (7.52)	$ (1.85)	$ (19.38)
Diluted net loss per common share (in dollars per share)	$ (0.65)	$ (7.52)	$ (1.85)	$ (19.38)
Basic weighted average common shares outstanding (in shares)	22,653,410	1,254,808	19,335,170	1,254,724
Diluted weighted average common shares outstanding (in shares)	22,653,410	1,254,808	19,335,170	1,254,724

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Summary of Antidilutive Securities Outstanding (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	3,340,627	13,930,119	5,580,867	13,062,381
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	3,340,627	2,237,420	3,340,627	2,237,420
Redeemable convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	0	10,135,735	1,560,635	10,135,735
Convertible debt
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	0	1,542,484	679,404	674,746
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	0	14,480	201	14,480

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income tax provision (benefit)	$ 0	$ 0	$ 0	$ 0
Effective tax rate	0.00%	0.00%	0.00%	0.00%
Accruals related to uncertain tax positions	$ 0		$ 0		$ 0

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Retirement Benefits [Abstract]
Employer discretionary contribution amount	$ 54,506	$ 37,071	$ 184,476	$ 125,553