NextCure (NXTC) 10-Q2 Nov 232023 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2023	Oct. 30, 2023
Cover Abstract
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-38905
Entity Registrant Name	NextCure, Inc.
Entity Central Index Key	0001661059
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-5231247
Entity Address, Address Line One	9000 Virginia Manor Road
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Beltsville
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20705
City Area Code	240
Local Phone Number	399-4900
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	NXTC
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		27,903,027
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 19,519	$ 26,630
Marketable securities	98,687	133,281
Prepaid expenses and other current assets	4,478	4,072
Total current assets	122,684	163,983
Property and equipment, net	9,844	11,897
Right of use assets	4,557	5,016
Other assets	2,854	3,265
Total assets	139,939	184,161
Current liabilities:
Accounts payable	2,602	4,270
Accrued liabilities and other liabilities	3,950	4,857
Total current liabilities	6,552	9,127
Lease liabilities, long term	6,120	6,605
Other long-term liabilities	815	899
Total liabilities	13,487	16,631
Stockholders' equity
Preferred stock; par value of $0.001 per share; 10,000,000 shares authorized at September 30, 2023 and December 31, 2022, No shares issued and outstanding at September 30, 2023 and December 31, 2022
Common stock, par value of $0.001 per share; 100,000,000 shares authorized at September 30, 2023 and December 31, 2022. 27,839,968 and 27,774,536 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively	28	28
Additional paid-in capital	437,042	430,755
Accumulated other comprehensive loss	(603)	(1,494)
Accumulated deficit	(310,015)	(261,759)
Total stockholders' equity	126,452	167,530
Total liabilities and stockholders' equity	$ 139,939	$ 184,161

CONDENSED BALANCE SHEETS - (Par

CONDENSED BALANCE SHEETS - (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
CONDENSED BALANCE SHEETS
Preferred stock, par value per share	$ 0.001	$ 0.001
Preferred stock, number of shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, number of shares authorized	100,000,000	100,000,000
Common stock, shares issued	27,839,968	27,774,536
Common stock, shares outstanding	27,839,968	27,774,536

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating expenses:
Research and development	$ 11,010	$ 13,528	$ 36,104	$ 41,377
General and administrative	4,608	5,711	15,743	16,761
Total operating expenses	15,618	19,239	51,847	58,138
Loss from operations	(15,618)	(19,239)	(51,847)	(58,138)
Other income, net	1,317	328	3,591	705
Net loss	$ (14,301)	$ (18,911)	$ (48,256)	$ (57,433)
Net loss per common share
Basic (in dollars per share)	$ (0.51)	$ (0.68)	$ (1.73)	$ (2.07)
Diluted (in dollars per share)	$ (0.51)	$ (0.68)	$ (1.73)	$ (2.07)
Weighted average shares outstanding
Basic (in shares)	27,839,968	27,748,844	27,814,655	27,734,271
Diluted (in shares)	27,839,968	27,748,844	27,814,655	27,734,271
Comprehensive loss:
Net loss	$ (14,301)	$ (18,911)	$ (48,256)	$ (57,433)
Unrealized gain (loss) on marketable securities	322	(56)	891	(1,733)
Total comprehensive loss	$ (13,979)	$ (18,967)	$ (47,365)	$ (59,166)

CONDENSED STATEMENTS OF STOCKHO

CONDENSED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Balance at the beginning at Dec. 31, 2021	$ 28	$ 421,047	$ (663)	$ (187,026)	$ 233,386
Balance at the beginning (in shares) at Dec. 31, 2021	27,680,997
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,628			2,628
Exercise of stock options		60			60
Exercise of stock options (in shares)	44,165
Unrealized gain (loss) on marketable securities, net of tax $0			(1,536)		(1,536)
Net loss				(20,602)	(20,602)
Balance at the end at Mar. 31, 2022	$ 28	423,735	(2,199)	(207,628)	213,936
Balance at the end (in shares) at Mar. 31, 2022	27,725,162
Balance at the beginning at Dec. 31, 2021	$ 28	421,047	(663)	(187,026)	233,386
Balance at the beginning (in shares) at Dec. 31, 2021	27,680,997
Increase (Decrease) in Stockholders' Deficit
Net loss					(57,433)
Balance at the end at Sep. 30, 2022	$ 28	428,368	(2,396)	(244,459)	181,541
Balance at the end (in shares) at Sep. 30, 2022	27,748,844
Balance at the beginning at Mar. 31, 2022	$ 28	423,735	(2,199)	(207,628)	213,936
Balance at the beginning (in shares) at Mar. 31, 2022	27,725,162
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,242			2,242
Exercise of stock options		6			6
Exercise of stock options (in shares)	6,255
Issuance of shares under ESPP		73			73
Issuance of shares under ESPP (in shares)	17,427
Unrealized gain (loss) on marketable securities, net of tax $0			(141)		(141)
Net loss				(17,920)	(17,920)
Balance at the end at Jun. 30, 2022	$ 28	426,056	(2,340)	(225,548)	198,196
Balance at the end (in shares) at Jun. 30, 2022	27,748,844
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,312			2,312
Unrealized gain (loss) on marketable securities, net of tax $0			(56)		(56)
Net loss				(18,911)	(18,911)
Balance at the end at Sep. 30, 2022	$ 28	428,368	(2,396)	(244,459)	181,541
Balance at the end (in shares) at Sep. 30, 2022	27,748,844
Balance at the beginning at Dec. 31, 2022	$ 28	430,755	(1,494)	(261,759)	$ 167,530
Balance at the beginning (in shares) at Dec. 31, 2022	27,774,536				27,774,536
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,078			$ 2,078
Unrealized gain (loss) on marketable securities, net of tax $0			691		691
Net loss				(16,096)	(16,096)
Balance at the end at Mar. 31, 2023	$ 28	432,833	(803)	(277,855)	154,203
Balance at the end (in shares) at Mar. 31, 2023	27,774,536
Balance at the beginning at Dec. 31, 2022	$ 28	430,755	(1,494)	(261,759)	$ 167,530
Balance at the beginning (in shares) at Dec. 31, 2022	27,774,536				27,774,536
Increase (Decrease) in Stockholders' Deficit
Net loss					$ (48,256)
Balance at the end at Sep. 30, 2023	$ 28	437,042	(603)	(310,015)	$ 126,452
Balance at the end (in shares) at Sep. 30, 2023	27,839,968				27,839,968
Balance at the beginning at Mar. 31, 2023	$ 28	432,833	(803)	(277,855)	$ 154,203
Balance at the beginning (in shares) at Mar. 31, 2023	27,774,536
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,125			2,125
Exercise of stock options		5			5
Exercise of stock options (in shares)	5,057
Issuance of shares under ESPP		78			78
Issuance of shares under ESPP (in shares)	60,375
Unrealized gain (loss) on marketable securities, net of tax $0			(122)		(122)
Net loss				(17,859)	(17,859)
Balance at the end at Jun. 30, 2023	$ 28	435,041	(925)	(295,714)	138,430
Balance at the end (in shares) at Jun. 30, 2023	27,839,968
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,001			2,001
Unrealized gain (loss) on marketable securities, net of tax $0			322		322
Net loss				(14,301)	(14,301)
Balance at the end at Sep. 30, 2023	$ 28	$ 437,042	$ (603)	$ (310,015)	$ 126,452
Balance at the end (in shares) at Sep. 30, 2023	27,839,968				27,839,968

CONDENSED STATEMENTS OF STOCK_2

CONDENSED STATEMENTS OF STOCKHOLDERS EQUITY (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
CONDENSED STATEMENTS OF STOCKHOLDERS EQUITY
Unrealized gain (loss) on marketable securities, tax expense (benefit)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (48,256)	$ (57,433)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,860	3,117
Amortization of premiums and discounts on marketable securities	(432)	2,594
Stock-based compensation	6,204	7,182
Noncash operating lease expense	426
Changes in operating assets and liabilities:
Prepaid expenses and other assets	38	234
Accounts payable	(1,668)	(95)
Accrued liabilities and other liabilities	(907)	(536)
Lease liabilities	(485)
Other long-term liabilities	(84)
Net cash used in operating activities	(42,304)	(44,937)
Cash flows from investing activities:
Sales and maturities of marketable securities	97,605	78,029
Purchases of marketable securities	(61,688)	(13,267)
Purchases of property and equipment	(807)	(1,251)
Net cash provided by investing activities	35,110	63,511
Cash flows from financing activities:
Proceeds from exercise of stock options	5	66
Proceeds from shares issued under ESPP	78	73
Net cash provided by financing activities	83	139
Net increase (decrease) in cash and cash equivalents	(7,111)	18,713
Cash and cash equivalents - beginning of period	26,630	12,376
Cash and cash equivalents - end of period	19,519	31,089
Supplemental disclosures of cash flow information:
Cash paid for interest	$ 62	$ 68

Nature of the Business

Nature of the Business	9 Months Ended
Nature of the Business	Sep. 30, 2023
Nature of the Business
Nature of the Business	1. Nature of the Business Organization NextCure, Inc. (“NextCure” or the “Company”) was incorporated in Delaware in September 2015 and is headquartered in Beltsville, Maryland. The Company is a clinical-stage biopharmaceutical company committed to discovering and developing novel, first-in-class immunomedicines to treat cancer and other immune-related diseases by restoring normal immune function. Through its proprietary Functional, Integrated, NextCure Discovery in Immuno-Oncology (“FIND-IO”) platform, the Company studies various immune cells in order to discover and understand targets and structural components of immune cells and their functional impact in order to develop immunomedicines. Since inception, the Company has devoted substantially all its efforts and financial resources to organizing and staffing the Company, identifying business development opportunities, raising capital, securing intellectual property rights related to the Company’s product candidates, building and optimizing the Company’s manufacturing capabilities and conducting discovery, research and development activities for the Company’s product candidates, discovery programs and its FIND-IO platform. Liquidity The Company has not generated any revenue to date from product sales and does not expect to generate any revenues from product sales in the foreseeable future. Through September 30, 2023, the Company has funded its operations primarily with proceeds from public offerings of its common stock, private placements of its preferred stock and upfront fees received under the Company’s former agreement with Eli Lilly and Company, which was terminated in March 2020. The Company expects to incur additional operating losses and negative operating cash flows for the foreseeable future. As of September 30, 2023, the Company had cash, cash equivalents and marketable securities of $118.2 million. The Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund its planned operations for at least the next twelve months from the issuance of these financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2023
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The following significant accounting policy is in addition to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the “Annual Report”). Collaboration Arrangements A collaborative arrangement within the scope of ASC 808 may be partially (or entirely) within the scope of other guidance (including ASC 606). The Company evaluates the individual units of account (e.g., components) within a collaborative arrangement to assess the appropriate recognition and measurement. The Company accounts for components of a collaborative arrangement that are within the scope of other ASC guidance following the relevant provisions of that guidance rather than the guidance provided in ASC 808. ASC 808 states that a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer for a distinct good or service (i.e., a unit of account). That is, the Company is required to apply the unit-of-account guidance in ASC 606 to determine the distinct components of a collaborative arrangement. If the counterparty is a customer for that distinct good or service (or bundle of goods and/or services), it is accounted for under ASC 606. For units of account that are in the scope of ASC 606, all of the guidance in ASC 606 applies, including the guidance on recognition, measurement, presentation and disclosure. The Company accounts for collaborative arrangements or components of collaborative arrangements that are outside the scope of other guidance by analogy to the authoritative accounting literature or, if there is no appropriate analogy, by using a reasonable, rational and consistently applied accounting policy election. When evaluating an appropriate analogy to other accounting guidance or an accounting policy for a collaborative arrangement, the Company assesses the nature of the arrangement, the nature of its business operations and the contractual terms of the arrangement. The Company recognizes the shared costs incurred that are not within the scope of other accounting literature as a component of the related expense in the period incurred by analogy to ASC 730, Research and Development, and records reimbursements from counterparties as an offset to the related research and development costs. Basis of Presentation The unaudited condensed financial statements include the accounts of the Company and have been prepared by the Company in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto in the Annual Report. Unaudited Financial Information In the opinion of management, the information furnished reflects certain adjustments, all which are of a normal and recurring nature and are necessary for a fair presentation of the Company’s financial position as of the reported balance sheet date and of the Company’s results for the reported interim periods. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities as of the date of the condensed financial statements, and the reported amounts of revenues and expenses during the reporting periods. Although actual results could differ from those estimates, management does not believe that such differences would be material. Recently Issued Accounting Pronouncements The Company qualifies as an emerging growth company (“EGC”) as defined under the Jumpstart Our Business Startups Act (the “JOBS Act”). Using exemptions provided under the JOBS Act provided to EGCs, the Company has elected to defer compliance with new or revised financial accounting standards until it is required to comply with such standards, which is generally consistent with required adoption dates of private companies. The Company considers the applicability and impact of all Accounting Standards Updates (“ASUs”) issued by the Financial Accounting Standards Board (“FASB”). All other ASUs issued subsequent to the filing of the Company’s Annual Report were assessed and determined to be either inapplicable or not expected to have a material impact on the Company’s financial position or results of operations.

Marketable Securities

Marketable Securities	9 Months Ended
Marketable Securities	Sep. 30, 2023
Marketable Securities
Marketable Securities	3. Marketable Securities Marketable securities consist of the following: September 30, 2023 Gross Gross Amortized Unrealized Unrealized Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds $ 72,232 $ — $ (473) $ 71,759 U.S. Treasury and Government agencies 27,058 — (130) 26,928 Total $ 99,290 $ — $ (603) $ 98,687 December 31, 2022 Gross Gross Amortized Unrealized Unrealized Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds $ 133,163 $ — $ (1,457) $ 131,706 U.S. Treasury and Government agencies 1,612 — (37) 1,575 Total $ 134,775 $ — $ (1,494) $ 133,281 The Company uses the specific identification method when calculating realized gains and losses. For the three months ended September 30, 2023 and 2022, respectively, the Company recorded $0 and $7,000 in realized gains on available-for-sale securities, which is included in other income, net on the condensed statements of operations. For the nine months ended September 30, 2023 and 2022, respectively, the Company recorded $0 and $9,000 in realized gains on available-for-sale securities, which is included in other income, net on the condensed statements of operations. The Company reviewed all investments which were in a loss position at the respective balance sheet dates, as well as the remainder of the portfolio. As of September 30, 2023, the Company had investments with a total fair market value of $98.7 million in an unrealized loss position, of which $18.4 million were in a continuous unrealized loss position for more than twelve months. The Company analyzed the unrealized losses and determined that the prevailing high interest rates were the primary factor driving these changes, and such unrealized losses are temporary as the Company anticipates a full recovery of the amortized cost basis of these securities at maturity. After analyzing the securities in an unrealized loss position, the portion of these losses that relates to changes in credit quality is insignificant. The Company does not intend to sell these securities, nor is it more likely than not that the Company will be required to sell them prior to the end of their contractual terms. Furthermore, the Company does not believe that these securities expose the Company to undue market risk or counterparty credit risk. The following table summarizes maturities of the Company’s investments available-for-sale as of September 30, 2023 : September 30, 2023 Fair (in thousands) Cost Value Maturities: Within 1 year $ 97,274 $ 96,695 Between 1 to 2 years 2,016 1,992 Total investments available-for-sale $ 99,290 $ 98,687 The Company has classified all of its available-for-sale investments, including those with maturities beyond one year, as current assets on the accompanying condensed balance sheets based on the highly liquid nature of these investment securities and because these investment securities are considered available for use in current operations.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2023
Fair Value Measurements
Fair Value Measurements	4. Fair Value Measurements The Company has certain financial assets recorded at fair value, which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. Level 1—Quoted market prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The following tables set forth the fair value of the Company’s financial assets by level within the fair value hierarchy as of September 30, 2023 and December 31, 2022: September 30, 2023 Significant Quoted Prices in Other Active Markets or Observable Significant Identical Assets Inputs Unobservable (in thousands) Total (Level 1) (Level 2) (Level 3) Cash equivalents: Money market funds $ 19,332 $ 19,332 $ — $ — Marketable securities: Corporate bonds 71,759 — 71,759 — U.S. Treasury and Government agencies 26,928 — 26,928 — Total $ 118,019 $ 19,332 $ 98,687 $ — December 31, 2022 Significant Quoted Prices in Other Active Markets or Observable Significant Identical Assets Inputs Unobservable (in thousands) Total (Level 1) (Level 2) (Level 3) Cash equivalents: Money market funds $ 6,782 $ 6,782 $ — $ — Marketable securities: Corporate bonds 131,706 — 131,706 — U.S. Treasury and Government agencies 1,575 — 1,575 — Total $ 140,063 $ 6,782 $ 133,281 $ — The Company did

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2023
Leases
Leases	5. Leases The Company's lease portfolio consists of office space and laboratory facilities. All of the Company's leases are classified as operating leases. The terms of the Company's lease agreements currently extend through March 2030 and provide the Company with an option for a five-year extension. Under the terms of the leases, the Company pays base annual rent subject to fixed dollar increases each year and other normal operating expenses such as taxes, repairs, and maintenance. The Company evaluates renewal options at lease inception and on an ongoing basis and considers renewal options that the Company is reasonably certain to exercise in its expected lease terms when classifying leases and measuring lease liabilities in accordance with ASC 842. The leases do not require variable lease payments or residual value guarantees and do not contain restrictive covenants. The leases do not provide an implicit rate; therefore, the Company uses its incremental borrowing rate as the discount rate when measuring the operating lease liability. The incremental borrowing rate represents an estimate of the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of the lease. Operating lease expense was $272,000 and $816,000 for the three and nine months ended September 30, 2023, respectively. Operating cash flows used for operating leases during the three and nine months ended September 30, 2023 were $245,000 and $757,000 , respectively. As of September 30, 2023, the weighted-average remaining lease term was 6.50 years, and the weighted average discount rate was 7.46% . Rent expense under operating leases was $248,000 and $739,000 for the three and nine months ended September 30, 2022, respectively. As of September 30, 2023, the maturities of the Company’s operating lease liabilities were as follows (in thousands), which are included in Accrued liabilities and other liabilities and Lease liabilities, long term in the accompanying balance sheet: 2023 $ 276 2024 1,127 2025 1,214 2026 1,355 2027 1,396 Thereafter 3,295 Total future minimum payments 8,663 Less: present value discount (1,907) Present value of lease liabilities $ 6,756

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2023
Stock-Based Compensation
Stock-Based Compensation	6. Stock-Based Compensation Employee Equity Plans The NextCure, Inc. 2015 Omnibus Incentive Plan (the “2015 Plan”) was adopted in December 2015 and provides for the grant of awards of stock options, restricted stock awards, unrestricted stock awards and restricted stock units to employees, consultants, and directors of the Company. The NextCure, Inc. 2019 Omnibus Incentive Plan (the “2019 Plan”) became effective on May 8, 2019, the date on which the Company’s Registration Statement on Form S-1 filed in connection with the IPO was declared effective (the “Effective Date”). The Company’s board of directors (the “Board”) determined not to make additional awards under the 2015 Plan following the effectiveness of the 2019 Plan. The 2019 Plan provides for the grant of awards of stock options, stock appreciation rights, restricted stock, restricted stock units, deferred stock units, unrestricted stock, dividend equivalent rights, other equity-based awards and cash bonus awards to the Company’s officers, employees, non-employee directors and other key persons (including consultants). The number of shares of common stock reserved for issuance under the 2019 Plan is 2,900,000 plus the number of shares of stock related to awards outstanding under the 2015 Plan that subsequently terminate by expiration or forfeiture, cancellation or otherwise without the issuance of such shares. As of September 30, 2023, 2,108,622 shares were reserved for future grant under the 2019 Plan. Stock options granted under the 2015 Plan and 2019 Plan (together, the “Plans”) to employees generally vest over four years and expire after ten years. A summary of stock option activity for awards under the Plans is presented below: Options Outstanding and Exercisable Weighted Weighted Average Aggregate Average Remaining Intrinsic Number of Exercise Contractual Value (1) Shares Price Life (Years) (in thousands) Outstanding as of December 31, 2022 5,262,179 $ 11.44 7.6 $ 115 Granted 2,059,250 $ 1.55 — — Exercised (5,057) $ 0.99 — — Forfeited (403,024) $ 5.23 — — Outstanding as of September 30, 2023 6,913,348 $ 8.86 7.5 $ 79 Exercisable as of September 30, 2023 3,720,545 $ 12.43 6.3 $ 79 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at September 30, 2023 and December 31, 2022. The weighted average grant date fair value of stock options granted to employees for the nine months ended September 30, 2023 was $1.12 using the Black-Scholes option pricing model. There were 5,057 stock options exercised during the nine months ended September 30, 2023. As of September 30, 2023, there was $9.7 million of total unrecognized compensation expense related to unvested options under the Plans that will be recognized over a weighted-average period of approximately 1.9 years. The aggregate grant date fair value of stock options vested during the nine months ended September 30, 2023 and 2022 was approximately $7.2 million and $9.0 million, respectively. Stock-based compensation expense was classified on the statements of operations as follows for the three and nine months ended September 30, 2023 and 2022: Three Months Ended Nine Months Ended September 30, September 30, (in thousands) 2023 2022 2023 2022 Research and development $ 721 $ 779 $ 2,184 $ 2,274 General and administrative 1,280 1,533 4,020 4,908 Total stock-based compensation expense $ 2,001 $ 2,312 $ 6,204 $ 7,182 The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions in the following table for options issued during the period indicated: Nine Months Ended September 30, 2023 2022 Expected term 6.1 years 5.5 - 6.1 years Expected volatility 81.4 % 79.7 % Risk free interest rate 3.5 - 4.1 % 1.8 - 3.1 % Expected dividend yield — % — % Employee Stock Purchase Plan The NextCure, Inc. 2019 Employee Stock Purchase Plan (the “ESPP”) was approved in May 2019 and provides for eligible employees of the Company to purchase shares of Company stock at a discounted price. As of September 30, 2023, 109,958 shares of common stock had been issued pursuant to the ESPP and 680,722 shares were reserved for future issuance thereunder.

Collaboration Agreements

Collaboration Agreements	9 Months Ended
Collaboration Agreements	Sep. 30, 2023
Collaboration Agreements
Collaboration Agreements	7. Collaboration Agreement with LegoChem Biosciences, Inc. (“LegoChem”) In November 2022, the Company entered into a Research Collaboration and Co-Development Agreement (“Agreement”) with LegoChem to develop up to three antibody drug conjugates. Under the terms of the Agreement, both parties equally share the costs of developing the molecules and profits on commercialized products. The collaboration consists of up to three research programs for which a research plan will be developed. With respect to a research plan, each party shall use reasonable efforts to execute and perform the activities assigned to it. Each party shall be solely responsible for costs associated with its assigned activities as outlined in the research plan. Upon successful completion of a research plan, or as otherwise agreed, the parties may designate a research product as a co-development product. Upon designation of a co-development product, cost sharing on a 50-50 basis between the Company and LegoChem would begin. The activities associated with the research plan and co-development products will be coordinated by a joint steering committee, which is comprised of an equal number of representatives from the Company and LegoChem. If and when a co-development product becomes commercialized, the Company and LegoChem would equally share in the profits. There are no implied licenses or other rights created under this Agreement after designation of a co-development product. Effective April 1, 2023, the parties designated the initial co-development product under the Agreement. As such, cost sharing on a 50-50 basis commenced for the first co-development product under the Agreement. Given the involvement by both parties under this Agreement, management assessed the criteria under ASC 808 to determine if such agreement is within the scope of ASC 808. Based on the terms of the Agreement, the Company concluded that the Agreement meets the requirements of a collaboration within the guidance of ASC 808. The Company and LegoChem are active participants in the activities associated with the Agreement and are exposed to significant risks and rewards dependent on the commercial success of the activity. The Agreement is not reflective of a vendor-customer relationship and therefore not within the scope of ASC 606. Accordingly, the net costs associated with the co-development are expensed as incurred and recognized within research and development expenses on the statement of operations. As of September 30, 2023, there is only one co-development product that is in the early stages of development and costs incurred have not been material.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended
Net Loss per Share Attributable to Common Stockholders	Sep. 30, 2023
Net Loss per Share Attributable to Common Stockholders
Net Loss per Share Attributable to Common Stockholders	8. Net Loss Per Share Attributable to Common Stockholders The computation of basic loss per share is based on the weighted-average number of common shares outstanding, without consideration for dilutive common stock equivalents. The computation of diluted loss per share is based on the weighted-average number of common shares outstanding and dilutive potential common shares, which include shares that may be issued under the 2015 Plan and 2019 Plan, as determined using the treasury stock method. The computation for basic and diluted loss per share were as follows (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, 2023 2022 2023 2022 Net loss (Numerator): Net loss - basic and diluted $ (14,301) $ (18,911) $ (48,256) $ (57,433) Shares (Denominator): Weighted-average shares outstanding - basic and diluted 27,839,968 27,748,844 27,814,655 27,734,271 Loss per share - basic and diluted $ (0.51) $ (0.68) $ (1.73) $ (2.07) For the three and nine months ended September 30, 2023 and 2022, all options to purchase shares of the Company’s common stock were excluded from the computation of diluted net loss per share as the effect would have been anti-dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share attributable to common stockholders for the period indicated because including them would have had an anti-dilutive effect: September 30, 2023 2022 Outstanding options to purchase common stock 6,913,348 5,276,833

Income Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2023
Income Taxes
Income Taxes	9. Income Taxes The Company did not record a provision or benefit for income taxes during the three and nine month periods ended September 30, 2023 and 2022. The Company continues to maintain a full valuation allowance against its deferred tax assets. The Company has evaluated the positive and negative evidence involving its ability to realize its deferred tax assets. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of any commercially ready products. It has concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets. Management reevaluates the positive and negative evidence at each reporting period. Under the provisions of Sections 382 and 383 of the Internal Revenue Code of 1986, as amended (the “IRC”), certain substantial changes in the Company’s ownership may have limited, or may limit in the future, the amount of net operating loss and research and development credit carryforwards that can be used to reduce future income taxes. We have not performed a detailed analysis to determine whether an ownership change under Section 382 of the IRC occurred. The effect of an ownership change would be the imposition of an annual limitation on the use of losses and credits attributable to periods before the change and could result in a reduction in the total losses and credits available.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2023
Commitments and Contingencies
Commitments and Contingencies	10. Commitments and Contingencies Legal Proceedings On September 21, 2020, a putative stockholder class action was filed in the U.S. District Court for the Southern District of New York styled Ye Zhou v. NextCure, Inc., et. al., Case 1:20-cv-0772 (S.D.N.Y.) (the “Ye Zhou Action”). On February 26, 2021, the Lead Plaintiff filed a consolidated amended complaint that asserts claims against us, certain of our officers and members of our board of directors, and the underwriters in our May 2019 initial public offering and November 2019 underwritten secondary public offering. The complaint alleges that the defendants violated provisions of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the Securities Act of 1933, as amended (the “Securities Act”), with respect to statements made regarding the Company’s NC318 product candidate and the FIND-IO platform. The complaint seeks unspecified damages on behalf of a purported class of purchasers of our securities between May 8, 2019 and July 14, 2020. Defendants filed a motion to dismiss the consolidated amended complaint on April 27, 2021, and on July 12, 2023 the court issued a memorandum opinion and order granting defendants’ motion to dismiss against all counts of the consolidated amended complaint. On July 13, 2023, judgement on behalf of Company and the other named defendants was entered and the case for the Ye Zhou Action was closed by the court. No appeals were filed by plaintiffs in the Ye Zhou to contest the district court’s order dismissing all claims in favor of Company. On March 24, 2021, a purported shareholder derivative lawsuit was filed in the U.S. District Court for the District of Maryland, Southern Division, styled Zach Liu v. Richman et. al., Case:21-cv-00754 (the “Liu Action”), alleging breaches of fiduciary duty by officers and/or directors, unjust enrichment, abuse of control, gross mismanagement, waste of corporate assets, and violations of the Exchange Act and the Securities Act. The complaint seeks unspecified damages, attorneys’ fees and costs, declaratory relief, corporate governance changes, and restitution. On May 17, 2021, the Court granted the parties’ joint motion to stay the Liu Action pending resolution of the defendants’ motion to dismiss filed in respect of the Ye Zhou Action. On August 1, 2023, Company filed a notice with the court in the Liu Action advising of the result of the motion to dismiss an entry of judgement in the Ye Zhou Action. On August 22, 2023, the Liu Action plaintiff filed a stipulation with the court to dismiss voluntarily all claims against Company, and the court in response closed the case for the Liu Action.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2023
Summary of Significant Accounting Policies
Collaboration Arrangements	Collaboration Arrangements A collaborative arrangement within the scope of ASC 808 may be partially (or entirely) within the scope of other guidance (including ASC 606). The Company evaluates the individual units of account (e.g., components) within a collaborative arrangement to assess the appropriate recognition and measurement. The Company accounts for components of a collaborative arrangement that are within the scope of other ASC guidance following the relevant provisions of that guidance rather than the guidance provided in ASC 808. ASC 808 states that a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer for a distinct good or service (i.e., a unit of account). That is, the Company is required to apply the unit-of-account guidance in ASC 606 to determine the distinct components of a collaborative arrangement. If the counterparty is a customer for that distinct good or service (or bundle of goods and/or services), it is accounted for under ASC 606. For units of account that are in the scope of ASC 606, all of the guidance in ASC 606 applies, including the guidance on recognition, measurement, presentation and disclosure. The Company accounts for collaborative arrangements or components of collaborative arrangements that are outside the scope of other guidance by analogy to the authoritative accounting literature or, if there is no appropriate analogy, by using a reasonable, rational and consistently applied accounting policy election. When evaluating an appropriate analogy to other accounting guidance or an accounting policy for a collaborative arrangement, the Company assesses the nature of the arrangement, the nature of its business operations and the contractual terms of the arrangement. The Company recognizes the shared costs incurred that are not within the scope of other accounting literature as a component of the related expense in the period incurred by analogy to ASC 730, Research and Development, and records reimbursements from counterparties as an offset to the related research and development costs.
Basis of Presentation and Unaudited Financial Information	Basis of Presentation The unaudited condensed financial statements include the accounts of the Company and have been prepared by the Company in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto in the Annual Report. Unaudited Financial Information In the opinion of management, the information furnished reflects certain adjustments, all which are of a normal and recurring nature and are necessary for a fair presentation of the Company’s financial position as of the reported balance sheet date and of the Company’s results for the reported interim periods. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities as of the date of the condensed financial statements, and the reported amounts of revenues and expenses during the reporting periods. Although actual results could differ from those estimates, management does not believe that such differences would be material.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements The Company qualifies as an emerging growth company (“EGC”) as defined under the Jumpstart Our Business Startups Act (the “JOBS Act”). Using exemptions provided under the JOBS Act provided to EGCs, the Company has elected to defer compliance with new or revised financial accounting standards until it is required to comply with such standards, which is generally consistent with required adoption dates of private companies. The Company considers the applicability and impact of all Accounting Standards Updates (“ASUs”) issued by the Financial Accounting Standards Board (“FASB”). All other ASUs issued subsequent to the filing of the Company’s Annual Report were assessed and determined to be either inapplicable or not expected to have a material impact on the Company’s financial position or results of operations.

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
Marketable Securities (Tables)	Sep. 30, 2023
Marketable Securities
Schedule of marketable securities	Marketable securities consist of the following: September 30, 2023 Gross Gross Amortized Unrealized Unrealized Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds $ 72,232 $ — $ (473) $ 71,759 U.S. Treasury and Government agencies 27,058 — (130) 26,928 Total $ 99,290 $ — $ (603) $ 98,687 December 31, 2022 Gross Gross Amortized Unrealized Unrealized Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds $ 133,163 $ — $ (1,457) $ 131,706 U.S. Treasury and Government agencies 1,612 — (37) 1,575 Total $ 134,775 $ — $ (1,494) $ 133,281
Schedule of available-for-sale maturities	The following table summarizes maturities of the Company’s investments available-for-sale as of September 30, 2023 : September 30, 2023 Fair (in thousands) Cost Value Maturities: Within 1 year $ 97,274 $ 96,695 Between 1 to 2 years 2,016 1,992 Total investments available-for-sale $ 99,290 $ 98,687

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2023
Fair Value Measurements
Summary of fair value of the Company's financial assets	The following tables set forth the fair value of the Company’s financial assets by level within the fair value hierarchy as of September 30, 2023 and December 31, 2022: September 30, 2023 Significant Quoted Prices in Other Active Markets or Observable Significant Identical Assets Inputs Unobservable (in thousands) Total (Level 1) (Level 2) (Level 3) Cash equivalents: Money market funds $ 19,332 $ 19,332 $ — $ — Marketable securities: Corporate bonds 71,759 — 71,759 — U.S. Treasury and Government agencies 26,928 — 26,928 — Total $ 118,019 $ 19,332 $ 98,687 $ — December 31, 2022 Significant Quoted Prices in Other Active Markets or Observable Significant Identical Assets Inputs Unobservable (in thousands) Total (Level 1) (Level 2) (Level 3) Cash equivalents: Money market funds $ 6,782 $ 6,782 $ — $ — Marketable securities: Corporate bonds 131,706 — 131,706 — U.S. Treasury and Government agencies 1,575 — 1,575 — Total $ 140,063 $ 6,782 $ 133,281 $ —

Leases (Tables)

Leases (Tables)	9 Months Ended
Leases (Tables)	Sep. 30, 2023
Leases
Schedule of future minimum lease payments under non-cancellable leases	As of September 30, 2023, the maturities of the Company’s operating lease liabilities were as follows (in thousands), which are included in Accrued liabilities and other liabilities and Lease liabilities, long term in the accompanying balance sheet: 2023 $ 276 2024 1,127 2025 1,214 2026 1,355 2027 1,396 Thereafter 3,295 Total future minimum payments 8,663 Less: present value discount (1,907) Present value of lease liabilities $ 6,756

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
Stock-Based Compensation (Tables)	Sep. 30, 2023
Stock-Based Compensation
Summary of stock option activity	Options Outstanding and Exercisable Weighted Weighted Average Aggregate Average Remaining Intrinsic Number of Exercise Contractual Value (1) Shares Price Life (Years) (in thousands) Outstanding as of December 31, 2022 5,262,179 $ 11.44 7.6 $ 115 Granted 2,059,250 $ 1.55 — — Exercised (5,057) $ 0.99 — — Forfeited (403,024) $ 5.23 — — Outstanding as of September 30, 2023 6,913,348 $ 8.86 7.5 $ 79 Exercisable as of September 30, 2023 3,720,545 $ 12.43 6.3 $ 79 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at September 30, 2023 and December 31, 2022.
Summary of stock based compensation expense recorded	Three Months Ended Nine Months Ended September 30, September 30, (in thousands) 2023 2022 2023 2022 Research and development $ 721 $ 779 $ 2,184 $ 2,274 General and administrative 1,280 1,533 4,020 4,908 Total stock-based compensation expense $ 2,001 $ 2,312 $ 6,204 $ 7,182
Summary of assumptions used in the Black Scholes option pricing model for stock options granted	Nine Months Ended September 30, 2023 2022 Expected term 6.1 years 5.5 - 6.1 years Expected volatility 81.4 % 79.7 % Risk free interest rate 3.5 - 4.1 % 1.8 - 3.1 % Expected dividend yield — % — %

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2023
Net Loss per Share Attributable to Common Stockholders
Summary of computation of basic and diluted net loss per share attributable to common stockholders	The computation for basic and diluted loss per share were as follows (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, 2023 2022 2023 2022 Net loss (Numerator): Net loss - basic and diluted $ (14,301) $ (18,911) $ (48,256) $ (57,433) Shares (Denominator): Weighted-average shares outstanding - basic and diluted 27,839,968 27,748,844 27,814,655 27,734,271 Loss per share - basic and diluted $ (0.51) $ (0.68) $ (1.73) $ (2.07)
Summary of shares excluded from the computation of diluted net loss per share	September 30, 2023 2022 Outstanding options to purchase common stock 6,913,348 5,276,833

Nature of the Business - Liquid

Nature of the Business - Liquidity (Details) $ in Millions	Sep. 30, 2023 USD ($)
Nature of the Business
Cash, cash equivalents and marketable securities	$ 118.2

Marketable Securities - (Detail

Marketable Securities - (Details) - USD ($)	3 Months Ended		9 Months Ended
Marketable Securities - (Details) - USD ($)	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Investments
Amortized Cost	$ 99,290,000		$ 99,290,000		$ 134,775,000
Gross Unrealized Loss	(603,000)		(603,000)		(1,494,000)
Estimated Fair Value	98,687,000		98,687,000		133,281,000
Unrealized losses in a continuous loss position for more than twelve consecutive months	18,400,000		18,400,000
Gross realized gains	0	$ 7,000	0	$ 9,000
Fair market value of investments in unrealized loss position	98,700,000		98,700,000
Cost Maturities:
Within 1 year	97,274,000		97,274,000
Between 1 to 2 years	2,016,000		2,016,000
Total investments available for sale	99,290,000		99,290,000
Fair Value Maturities:
Within 1 year	96,695,000		96,695,000
Between 1 to 2 years	1,992,000		1,992,000
Total investments available for sale	98,687,000		98,687,000
Corporate bonds
Investments
Amortized Cost	72,232,000		72,232,000		133,163,000
Gross Unrealized Loss	(473,000)		(473,000)		(1,457,000)
Estimated Fair Value	71,759,000		71,759,000		131,706,000
U.S. Treasury and Government agencies
Investments
Amortized Cost	27,058,000		27,058,000		1,612,000
Gross Unrealized Loss	(130,000)		(130,000)		(37,000)
Estimated Fair Value	$ 26,928,000		$ 26,928,000		$ 1,575,000

Fair Value Measurements - (Deta

Fair Value Measurements - (Details) - USD ($)	9 Months Ended
Fair Value Measurements - (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Fair value of the Company's financial assets
Marketable Securities	$ 98,687,000	$ 133,281,000
Assets transferred into level 3	0
Assets transferred out of level 3	0
Corporate bonds
Fair value of the Company's financial assets
Marketable Securities	71,759,000	131,706,000
U.S. Treasury and Government agencies
Fair value of the Company's financial assets
Marketable Securities	26,928,000	1,575,000
Fair Value
Fair value of the Company's financial assets
Total financial assets	118,019,000	140,063,000
Fair Value \| Money market funds (cash equivalents)
Fair value of the Company's financial assets
Money market funds (cash equivalents)	19,332,000	6,782,000
Fair Value \| Corporate bonds
Fair value of the Company's financial assets
Marketable Securities	71,759,000	131,706,000
Fair Value \| U.S. Government agencies
Fair value of the Company's financial assets
Marketable Securities		1,575,000
Fair Value \| U.S. Treasury and Government agencies
Fair value of the Company's financial assets
Marketable Securities	26,928,000
Fair Value \| Quoted Prices in Active Markets (Level 1)
Fair value of the Company's financial assets
Total financial assets	19,332,000	6,782,000
Fair Value \| Quoted Prices in Active Markets (Level 1) \| Money market funds (cash equivalents)
Fair value of the Company's financial assets
Money market funds (cash equivalents)	19,332,000	6,782,000
Fair Value \| Significant Other Observable Inputs (Level 2)
Fair value of the Company's financial assets
Total financial assets	98,687,000	133,281,000
Fair Value \| Significant Other Observable Inputs (Level 2) \| Corporate bonds
Fair value of the Company's financial assets
Marketable Securities	71,759,000	131,706,000
Fair Value \| Significant Other Observable Inputs (Level 2) \| U.S. Government agencies
Fair value of the Company's financial assets
Marketable Securities		$ 1,575,000
Fair Value \| Significant Other Observable Inputs (Level 2) \| U.S. Treasury and Government agencies
Fair value of the Company's financial assets
Marketable Securities	$ 26,928,000

Leases - Other Information (Det

Leases - Other Information (Details) - USD ($)	3 Months Ended		9 Months Ended
Leases - Other Information (Details) - USD ($)	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Leases
Lease extension period	5 years		5 years
Lessee, Operating Lease, Existence of Option to Extend [true false]			true
Operating lease expense	$ 272,000		$ 816,000
Operating cash flows used for operating leases	$ 245,000		$ 757,000
Weighted=average remaining lease term	6 years 6 months		6 years 6 months
Weighted average discount rate (as a percent)	7.46%		7.46%
Rent expenses operating leases		$ 248,000		$ 739,000

Leases - Maturities (Details)

Leases - Maturities (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Future minimum lease payments
2023	$ 276
2024	1,127
2025	1,214
2026	1,355
2027	1,396
Thereafter	3,295
Total future minimum payments	8,663
Less: present value discount	(1,907)
Present value of lease liabilities	$ 6,756

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended		12 Months Ended	50 Months Ended
	May 03, 2019	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jun. 30, 2023
2015 Plan
Number of Shares
Outstanding at the beginning (in shares)		5,262,179
Granted (in shares)		2,059,250
Exercised (in shares)		(5,057)
Forfeitures (in shares)		(403,024)
Outstanding at the end (in shares)		6,913,348		5,262,179
Exercisable at the end (in shares)		3,720,545
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)		$ 11.44
Granted (in dollars per share)		1.55
Exercised (in dollars per share)		0.99
Forfeited (in dollars per share)		5.23
Outstanding at the end (in dollars per share)		8.86		$ 11.44
Exercisable at the end (in dollars per share)		$ 12.43
Weighted Average Remaining Contractual Life (Years) And Aggregate Intrinsic Value
Outstanding (in years)		7 years 6 months		7 years 7 months 6 days
Exercisable at the end (in years)		6 years 3 months 18 days
Outstanding at the beginning (in dollars)		$ 115
Outstanding at the end (in dollars)		79		$ 115
Exercisable at the end (in dollars)		$ 79
Weighted average grant date fair value per share of stock options granted		$ 1.12
Aggregate grant date fair value		$ 7,200	$ 9,000
Share Based Compensation Expense Not Recognized
Unrecognized compensation cost		$ 9,700
Compensation expense recognition period		1 year 10 months 24 days
Omnibus Incentive Plan
Stock Based Compensation
Total number of shares of common stock that may be issued		2,900,000
Annual increase in number of share reserved for issuance (as percent)	4%
2015 Plan and 2019 Employee Stock Purchase Plan
Stock Based Compensation
Vesting period		4 years
Expiration period		10 years
Number of shares reserved for issuance under the plan		2,108,622
2019 Employee Stock Purchase Plan
Stock Based Compensation
Number of shares issued					109,958
Number of shares reserved for issuance under the plan		680,722

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock based compensation expense
Total stock-based compensation expense	$ 2,001	$ 2,312	$ 6,204	$ 7,182
Research and development
Stock based compensation expense
Total stock-based compensation expense	721	779	2,184	2,274
General and administrative
Stock based compensation expense
Total stock-based compensation expense	$ 1,280	$ 1,533	$ 4,020	$ 4,908

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions (Details)	9 Months Ended
Stock-Based Compensation - Assumptions (Details)	Sep. 30, 2023	Sep. 30, 2022
Fair value assumptions
Expected term	6 years 1 month 6 days
Expected volatility	81.40%	79.70%
Minimum
Fair value assumptions
Expected term		5 years 6 months
Risk free interest rate	3.50%	1.80%
Maximum
Fair value assumptions
Expected term		6 years 1 month 6 days
Risk free interest rate	4.10%	3.10%

Collaboration Agreements (Detai

Collaboration Agreements (Details) - Research Collaboration and Co-Development Agreement - LegoChem Biosciences - item	1 Months Ended
	Nov. 30, 2022	Sep. 30, 2023
Collaboration Agreements
Maximum number of antibody drug conjugates to be developed	3
Collaboration agreements cost sharing percentage (as a percent)	50%
Number of co-developed product in early stage of development		1

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Other (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Income loss (Numerator):
Net loss - basic and diluted	$ (14,301)	$ (17,859)	$ (16,096)	$ (18,911)	$ (17,920)	$ (20,602)	$ (48,256)	$ (57,433)
Shares (Denominator):
Weighted-average shares for basic EPS (in shares)	27,839,968			27,748,844			27,814,655	27,734,271
Weighted-average shares for diluted EPS (in shares)	27,839,968			27,748,844			27,814,655	27,734,271
Basic EPS (in dollars per share)	$ (0.51)			$ (0.68)			$ (1.73)	$ (2.07)
Diluted EPS (in dollars per share)	$ (0.51)			$ (0.68)			$ (1.73)	$ (2.07)

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Anti-dilutive effect (Details) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Option to purchase common stock
Antidilutive Securities
Antidilutive securities excluded from computation of diluted net loss per share	6,913,348	5,276,833

Income Taxes - (Details)

Income Taxes - (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Income Taxes - (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Taxes
Provision or benefit from income taxes	$ 0	$ 0	$ 0	$ 0