NextCure (NXTC) 10-Q 7 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 01, 2024
Cover Abstract
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Securities Act 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		28,006,684
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 27,702	$ 13,082
Marketable securities	47,606	95,217
Prepaid expenses and other current assets	3,385	4,426
Total current assets	78,693	112,725
Property and equipment, net	6,167	9,033
Right of use assets	3,415	4,398
Other assets	2,070	1,882
Total assets	90,345	128,038
Current liabilities:
Accounts payable	3,613	2,330
Accrued liabilities and other liabilities	5,059	4,553
Total current liabilities	8,672	6,883
Lease liabilities, long term	5,388	5,949
Other long-term liabilities	693	785
Total liabilities	14,753	13,617
Stockholders' equity:
Preferred stock, par value of $0.001 per share; 10,000,000 shares authorized at September 30, 2024 and December 31, 2023; No shares issued and outstanding at September 30, 2024 and December 31, 2023
Common stock, par value of $0.001 per share; 100,000,000 shares authorized at September 30, 2024 and December 31, 2023; 27,975,840 and 27,903,027 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively	28	28
Additional paid-in capital	444,021	439,097
Accumulated other comprehensive income (loss)	76	(222)
Accumulated deficit	(368,533)	(324,482)
Total stockholders' equity	75,592	114,421
Total liabilities and stockholders' equity	$ 90,345	$ 128,038

CONDENSED BALANCE SHEETS - (Par

CONDENSED BALANCE SHEETS - (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
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	27,975,840	27,903,027
Common stock, shares outstanding	27,975,840	27,903,027

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses:
Research and development	$ 8,770	$ 11,010	$ 32,586	$ 36,104
General and administrative	3,725	4,608	12,165	15,743
Restructuring and asset impairment charges			2,542
Total operating expenses	12,495	15,618	47,293	51,847
Loss from operations	(12,495)	(15,618)	(47,293)	(51,847)
Other income, net	955	1,317	3,242	3,591
Net loss	$ (11,540)	$ (14,301)	$ (44,051)	$ (48,256)
Net loss per common share
Basic (in dollars per share)	$ (0.41)	$ (0.51)	$ (1.58)	$ (1.73)
Diluted (in dollars per share)	$ (0.41)	$ (0.51)	$ (1.58)	$ (1.73)
Weighted average shares outstanding
Basic (in shares)	27,975,840	27,839,968	27,950,634	27,814,655
Diluted (in shares)	27,975,840	27,839,968	27,950,634	27,814,655
Comprehensive loss:
Net Income (Loss)	$ (11,540)	$ (14,301)	$ (44,051)	$ (48,256)
Unrealized gain on marketable securities	162	322	298	891
Total comprehensive loss	$ (11,378)	$ (13,979)	$ (43,753)	$ (47,365)

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, 2022	$ 28	$ 430,755	$ (1,494)	$ (261,759)	$ 167,530
Balance at the beginning (in shares) at Dec. 31, 2022	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 Income (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
Increase (Decrease) in Stockholders' Deficit
Net Income (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
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 Income (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 Income (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
Balance at the beginning at Dec. 31, 2023	$ 28	439,097	(222)	(324,482)	$ 114,421
Balance at the beginning (in shares) at Dec. 31, 2023	27,903,027				27,903,027
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		1,693			$ 1,693
Exercise of stock options		1			1
Exercise of stock options (in shares)	600
Unrealized gain (loss) on marketable securities, net of tax $0			40		40
Net Income (Loss)				(17,107)	(17,107)
Balance at the end at Mar. 31, 2024	$ 28	440,791	(182)	(341,589)	99,048
Balance at the end (in shares) at Mar. 31, 2024	27,903,627
Balance at the beginning at Dec. 31, 2023	$ 28	439,097	(222)	(324,482)	$ 114,421
Balance at the beginning (in shares) at Dec. 31, 2023	27,903,027				27,903,027
Increase (Decrease) in Stockholders' Deficit
Net Income (Loss)					$ (44,051)
Balance at the end at Sep. 30, 2024	$ 28	444,021	76	(368,533)	$ 75,592
Balance at the end (in shares) at Sep. 30, 2024	27,975,840				27,975,840
Balance at the beginning at Mar. 31, 2024	$ 28	440,791	(182)	(341,589)	$ 99,048
Balance at the beginning (in shares) at Mar. 31, 2024	27,903,627
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		1,594			1,594
Exercise of stock options		22			22
Exercise of stock options (in shares)	13,985
Issuance of shares under ESPP		46			46
Issuance of shares under ESPP (in shares)	41,077
Issuance of shares at-the-market sales, net of expenses		39			39
Issuance of shares from at-the-market sales, net of expenses (in shares)	17,151
Unrealized gain (loss) on marketable securities, net of tax $0			96		96
Net Income (Loss)				(15,404)	(15,404)
Balance at the end at Jun. 30, 2024	$ 28	442,492	(86)	(356,993)	85,441
Balance at the end (in shares) at Jun. 30, 2024	27,975,840
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		1,529			1,529
Unrealized gain (loss) on marketable securities, net of tax $0			162		162
Net Income (Loss)				(11,540)	(11,540)
Balance at the end at Sep. 30, 2024	$ 28	$ 444,021	$ 76	$ (368,533)	$ 75,592
Balance at the end (in shares) at Sep. 30, 2024	27,975,840				27,975,840

CONDENSED STATEMENTS OF STOCK_2

CONDENSED STATEMENTS OF STOCKHOLDERS EQUITY (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
CONDENSED STATEMENTS OF STOCKHOLDERS EQUITY
Unrealized gain (loss) on marketable securities, tax expense (benefit)	$ 0	$ 0	$ 0	$ 0

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (44,051)	$ (48,256)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,191	2,860
Amortization of premiums and discounts on marketable securities	(947)	(432)
Stock-based compensation	4,816	6,204
Asset impairment	1,786
Noncash operating lease expense	422	426
Changes in operating assets and liabilities:
Prepaid expenses and other assets	811	38
Accounts payable	1,283	(1,668)
Accrued liabilities and other liabilities	506	(907)
Lease liabilities	(561)	(485)
Other long-term liabilities	(92)	(84)
Net cash used in operating activities	(33,836)	(42,304)
Cash flows from investing activities:
Sales and maturities of marketable securities	88,965	97,605
Purchases of marketable securities	(40,109)	(61,688)
Purchases of property and equipment	(508)	(807)
Net cash provided by investing activities	48,348	35,110
Cash flows from financing activities:
Net proceeds from at-the-market sales	39
Proceeds from exercise of stock options	23	5
Proceeds from shares issued under ESPP	46	78
Net cash provided by financing activities	108	83
Net increase (decrease) in cash and cash equivalents	14,620	(7,111)
Cash and cash equivalents - beginning of period	13,082	26,630
Cash and cash equivalents - end of period	27,702	19,519
Supplemental disclosures of cash flow information:
Cash paid for interest	$ 55	$ 62

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2024
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 focused on advancing innovative medicines that treat cancer patients that do not respond to, or have disease progression on, current therapies, through the use of differentiated mechanisms of actions including antibody-drug conjugates, antibodies and proteins. We focus on advancing therapies that leverage our core strengths in understanding biological pathways and biomarkers, the interactions of cells, including in the tumor microenvironment, and the role each interaction plays in a biologic response. Since inception, the Company has devoted substantially all of its efforts and financial resources to discovery, research and development activities for the Company’s product candidates, identifying business development opportunities, raising capital and securing intellectual property rights related to the Company’s product candidates. 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, 2024, 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, 2024, the Company had cash, cash equivalents and marketable securities of $75.3 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
	Sep. 30, 2024
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The following significant accounting policies are 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, 2023 (the “Annual Report”). Restructuring Charges • contractual or other employee termination benefits provided that the obligations result from services already rendered based on rights that vested or accumulate when the payment of benefits becomes probable and the amount can be reasonably estimated; • one-time employee termination benefits to the employees provided that management has committed to a plan of termination, the plan identifies the employees and their expected termination dates, the details of termination benefits are complete, and it is unlikely that changes to the plan will be made or the plan will be withdrawn; • contract termination costs when the Company cancels a contract in accordance with its terms; and • costs to be incurred over the remaining contract term without economic benefit to the Company at the cease-use date. For one-time employee terminations benefits, the Company recognizes the liability in full on the communication date when future services are not required or amortizes the liability ratably over the service period, if required. The fair value of termination benefits reflects the Company’s estimate of expected utilization of certain Company-funded post-employment benefits. ​ Long-Lived Asset Impairment Assessments Long-lived assets, including operating lease assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The recoverability of assets to be held and used is measured by a comparison of the carrying amount of the asset group to future net cash flows estimated by the Company to be generated by such assets. If such asset group is considered to be impaired, the impairment to be recognized is the amount by which the carrying amount of the asset group exceeds the fair value of the asset group. 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 will cease to be an EGC effective December 31, 2024, meaning it will have to comply with all applicable SEC requirements for non-EGC’s starting with its next Form 10-K filing. 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
	Sep. 30, 2024
Marketable Securities
Marketable Securities	​ 3. Marketable Securities Marketable securities consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 39,586 ​ $ 72 ​ $ (2) ​ $ 39,656 U.S. Treasury and Government agencies ​ ​ 7,944 ​ ​ 6 ​ ​ — ​ ​ 7,950 Total ​ $ 47,530 ​ $ 78 ​ $ (2) ​ $ 47,606 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 73,334 ​ $ 36 ​ $ (210) ​ $ 73,160 U.S. Treasury and Government agencies ​ ​ 22,105 ​ ​ 5 ​ ​ (53) ​ ​ 22,057 Total ​ $ 95,439 ​ $ 41 ​ $ (263) ​ $ 95,217 ​ ​ The Company uses the specific identification method when calculating realized gains and losses. The Company did not realize any gains or losses on available-for-sale securities for the three and nine months ended September 30, 2024 and 2023. 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, 2024, the Company had investments with a total fair market value of $6.6 million in an immaterial unrealized loss position, of which none were in a continuous unrealized loss position for more than twelve months. The Company analyzed the unrealized losses and determined that market conditions 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, 2024 : ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ ​ ​ Fair (in thousands) Cost Value Maturities: ​ ​ ​ ​ ​ ​ Within 1 year ​ $ 40,992 ​ $ 41,042 Over 1 year ​ 6,538 ​ 6,564 Total investments available-for-sale ​ $ 47,530 ​ $ 47,606 ​ The Company has elected to report interest receivable from its marketable securities with prepaid expenses and other current assets on its balance sheet. Interest receivable included in prepaid expenses and other current assets totaled $0.3 million and $0.8 million as of September 30, 2024 and December 31, 2023, respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
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, 2024 and December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 27,346 ​ $ 27,346 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 39,656 ​ ​ — ​ ​ 39,656 ​ ​ — U.S. Treasury and Government agencies ​ ​ 7,950 ​ ​ — ​ ​ 7,950 ​ ​ — Total ​ $ 74,952 ​ $ 27,346 ​ $ 47,606 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 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 ​ $ 12,582 ​ $ 12,582 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 73,160 ​ ​ — ​ ​ 73,160 ​ ​ — U.S. Treasury and Government agencies ​ ​ 22,057 ​ ​ — ​ ​ 22,057 ​ ​ — Total ​ $ 107,799 ​ $ 12,582 ​ $ 95,217 ​ $ — ​ ​ The Company did

Leases

Leases	9 Months Ended
	Sep. 30, 2024
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 Accounting Standards Codification (“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 $253,000 and $272,000 for the three months ended September 30, 2024 and September 30, 2023, respectively. Operating lease expense was $779,000 and $816,000 for the nine months ended September 30, 2024 and September 30, 2023, respectively. Operating cash flows used for operating leases during the nine months ended September 30, 2024 and September 30, 2023 were $843,000 and $757,000 , respectively. As of September 30, 2024, the weighted-average remaining lease term was 5.5 years, and the weighted average discount rate was 7.47% . As of September 30, 2024, 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2024 ​ $ 284 ​ ​ ​ 2025 ​ 1,214 ​ ​ ​ 2026 ​ 1,355 ​ ​ ​ 2027 ​ 1,396 ​ ​ ​ 2028 ​ ​ 1,438 ​ ​ ​ Thereafter ​ 1,857 ​ ​ ​ Total future minimum payments ​ $ 7,544 ​ ​ ​ Less: present value discount ​ ​ (1,424) ​ ​ ​ Present value of lease liabilities ​ $ 6,120 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2024
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, 2024, 1,221,931 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, 2023 6,817,102 ​ $ 8.83 7.3 ​ $ 52 Granted ​ 2,974,950 ​ $ 1.65 ​ — ​ ​ — Exercised ​ (14,585) ​ $ 1.55 ​ — ​ ​ — Forfeitures ​ (885,459) ​ $ 3.43 ​ — ​ ​ — Outstanding as of September 30, 2024 ​ 8,892,008 ​ $ 6.98 ​ 7.3 ​ ​ 303 Exercisable as of September 30, 2024 4,844,594 ​ $ 10.82 6.0 ​ $ 101 (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 December 31, 2023 and September 30, 2024. The weighted average grant date fair value of stock options granted to employees for the nine months ended September 30, 2024 was $1.19 using the Black-Scholes option pricing model. There were 14,585 stock options exercised during the nine months ended September 30, 2024. As of September 30, 2024, there was $5.4 million of total unrecognized compensation expense related to unvested options under the Plans that will be recognized over a weighted-average period of approximately 1.6 years. The aggregate grant date fair value of stock options vested during the nine months ended September 30, 2024 and 2023 was approximately $4.0 million and $7.2 million, respectively. Stock-based compensation expense was classified on the statements of operations as follows for the three and nine months ended September 30, 2024 and 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ (in thousands) 2024 2023 2024 2023 ​ Research and development ​ $ 689 ​ $ 721 ​ $ 2,072 ​ $ 2,184 ​ General and administrative ​ 840 ​ 1,280 ​ 2,744 ​ 4,020 ​ Total stock-based compensation expense ​ $ 1,529 ​ $ 2,001 ​ $ 4,816 ​ $ 6,204 ​ ​ ​ 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, ​ ​ 2024 2023 ​ Expected term 5.8 years ​ 6.1 years ​ Expected volatility 83.3 % ​ 81.4 % ​ Risk free interest rate 4.1 % ​ 3.5 - 4.1 % ​ 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, 2024, 214,094 shares of common stock had been issued pursuant to the ESPP and 855,616 shares were reserved for future issuance thereunder.

Collaboration Agreements

Collaboration Agreements	9 Months Ended
	Sep. 30, 2024
Collaboration Agreements
Collaboration Agreements	7. Collaboration Agreement with LigaChem Biosciences, Inc. (“LigaChem”), formerly known as LegoChem Biosciences In November 2022, the Company entered into a Research Collaboration and Co-Development Agreement (“Agreement”) with LigaChem 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 LigaChem 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 LigaChem. If and when a co-development product becomes commercialized, the Company and LigaChem 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 LigaChem 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 pursuant to the Agreement are expensed as incurred and recognized within research and development expenses on the statement of operations. As of September 30, 2024, LNCB74 was the lone co-development product and was in the early stages of development. During the three and nine months ended September 30, 2024, the Company incurred more costs than LigaChem under the Agreement, and recorded a reduction in costs of $0.3 million and $1.7 million, respectively, reflecting the 50-50 cost sharing terms under the Agreement. Further, the Company and LigaChem finalized the cost sharing adjustments from the fourth quarter of 2023, resulting in an additional reduction in costs of $1.6 million that was recorded in the first quarter of 2024. As of September 30, 2024, the Company recorded a receivable from LigaChem of $0.5 million.

Restructuring and Asset Impairm

Restructuring and Asset Impairment	9 Months Ended
	Sep. 30, 2024
Restructuring and Asset Impairment
Restructuring and Asset Impairment	8. Restructuring and Asset Impairment On March 19, 2024, the Board approved a restructuring plan and prioritization (the “2024 Restructuring”) of its clinical portfolio to focus on what the Company believes to be its highest-value opportunities in NC410 (ovarian and colorectal cancer) and LNCB74 (B7-H4 ADC). In addition to prioritizing these programs, the Company paused its internal manufacturing operations and reduced its workforce by approximately 37%. Employees affected by the reduction in force under the 2024 Restructuring were entitled to receive severance payments and Company-funded medical insurance for a specified time. During the three months ended March 31, 2024, the Company recognized $0.8 million for employees who had no requirements for future service upon approval of the 2024 Restructuring. This $0.8 million was paid out in full during the three months ended June 30, 2024, and there is no remaining liability as of September 30, 2024. The Company also completed an evaluation of the impact of the 2024 Restructuring on the carrying value of its long-lived assets. Our evaluation determined that indicators of impairment were present within right of use assets and property and equipment. Where impairment indicators existed, the Company evaluated the identified asset group and separately compared the estimated undiscounted cash flow for each asset group to the net book value of the related long-term asset. Based on this evaluation, the Company determined an impairment was present and then calculated the amount of the impairment by developing a fair value estimate of the asset group that was compared to the carrying value. The Company recorded $1.8 million of impairment charges related to a facility operating lease asset and accelerated depreciation on manufacturing equipment for the three months ended March 31, 2024. No additional impairment charges were recorded for the three months ended September 30, 2024. Assumptions used in this analysis included current real estate trends, length of time to enter into a sublease and the discount rate used to develop the present value estimate. Other assumptions included an estimate of the salvage value for manufacturing equipment that is no longer in use. These assumptions are considered nonrecurring Level 3 estimates.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2024
Net Loss per Share Attributable to Common Stockholders
Net Loss per Share Attributable to Common Stockholders	9. 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, ​ ​ 2024 2023 2024 2023 ​ Net loss (Numerator): ​ ​ ​ ​ ​ ​ Net loss - basic and diluted ​ $ (11,540) ​ $ (14,301) ​ $ (44,051) ​ $ (48,256) ​ Shares (Denominator): ​ ​ ​ ​ ​ Weighted-average shares outstanding - basic and diluted ​ 27,975,840 ​ 27,839,968 ​ 27,950,634 ​ 27,814,655 ​ Loss per share - basic and diluted ​ $ (0.41) ​ $ (0.51) ​ $ (1.58) ​ $ (1.73) ​ ​ ​ For the three and nine months ended September 30, 2024 and 2023, 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, ​ 2024 2023 Outstanding options to purchase common stock ​ 8,892,008 ​ 6,913,348 Total ​ 8,892,008 ​ 6,913,348 ​

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Taxes
Income Taxes	10. Income Taxes The Company did not record a provision or benefit for income taxes during the three and nine month periods ended September 30, 2024 and 2023. 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
	Sep. 30, 2024
Commitments and Contingencies.
Commitments and Contingencies	11. Commitments and Contingencies Legal Proceedings From time to time, the Company is a party to litigation or legal proceedings arising in the ordinary course of business. The Company is not currently a party to any litigation or legal proceeding, nor is management aware of any pending or threatened litigation that, in the opinion of the Company’s management, is likely to materially affect the Company’s business or financial results. At each reporting date, the Company evaluates whether a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses the costs related to its legal proceedings as incurred.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (11,540)	$ (15,404)	$ (17,107)	$ (14,301)	$ (17,859)	$ (16,096)	$ (44,051)	$ (48,256)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Summary of Significant Accounting Policies
Restructuring Charges	Restructuring Charges • contractual or other employee termination benefits provided that the obligations result from services already rendered based on rights that vested or accumulate when the payment of benefits becomes probable and the amount can be reasonably estimated; • one-time employee termination benefits to the employees provided that management has committed to a plan of termination, the plan identifies the employees and their expected termination dates, the details of termination benefits are complete, and it is unlikely that changes to the plan will be made or the plan will be withdrawn; • contract termination costs when the Company cancels a contract in accordance with its terms; and • costs to be incurred over the remaining contract term without economic benefit to the Company at the cease-use date. For one-time employee terminations benefits, the Company recognizes the liability in full on the communication date when future services are not required or amortizes the liability ratably over the service period, if required. The fair value of termination benefits reflects the Company’s estimate of expected utilization of certain Company-funded post-employment benefits.
Long-Lived Asset Impairment Assessments	Long-Lived Asset Impairment Assessments Long-lived assets, including operating lease assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The recoverability of assets to be held and used is measured by a comparison of the carrying amount of the asset group to future net cash flows estimated by the Company to be generated by such assets. If such asset group is considered to be impaired, the impairment to be recognized is the amount by which the carrying amount of the asset group exceeds the fair value of the asset group.
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 will cease to be an EGC effective December 31, 2024, meaning it will have to comply with all applicable SEC requirements for non-EGC’s starting with its next Form 10-K filing. 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
	Sep. 30, 2024
Marketable Securities
Schedule of marketable securities	Marketable securities consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 39,586 ​ $ 72 ​ $ (2) ​ $ 39,656 U.S. Treasury and Government agencies ​ ​ 7,944 ​ ​ 6 ​ ​ — ​ ​ 7,950 Total ​ $ 47,530 ​ $ 78 ​ $ (2) ​ $ 47,606 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 73,334 ​ $ 36 ​ $ (210) ​ $ 73,160 U.S. Treasury and Government agencies ​ ​ 22,105 ​ ​ 5 ​ ​ (53) ​ ​ 22,057 Total ​ $ 95,439 ​ $ 41 ​ $ (263) ​ $ 95,217
Schedule of available-for-sale maturities	The following table summarizes maturities of the Company’s investments available-for-sale as of September 30, 2024 : ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ ​ ​ Fair (in thousands) Cost Value Maturities: ​ ​ ​ ​ ​ ​ Within 1 year ​ $ 40,992 ​ $ 41,042 Over 1 year ​ 6,538 ​ 6,564 Total investments available-for-sale ​ $ 47,530 ​ $ 47,606

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
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, 2024 and December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 27,346 ​ $ 27,346 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 39,656 ​ ​ — ​ ​ 39,656 ​ ​ — U.S. Treasury and Government agencies ​ ​ 7,950 ​ ​ — ​ ​ 7,950 ​ ​ — Total ​ $ 74,952 ​ $ 27,346 ​ $ 47,606 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 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 ​ $ 12,582 ​ $ 12,582 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 73,160 ​ ​ — ​ ​ 73,160 ​ ​ — U.S. Treasury and Government agencies ​ ​ 22,057 ​ ​ — ​ ​ 22,057 ​ ​ — Total ​ $ 107,799 ​ $ 12,582 ​ $ 95,217 ​ $ —

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2024
Leases
Schedule of future minimum lease payments under non-cancellable leases	As of September 30, 2024, 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2024 ​ $ 284 ​ ​ ​ 2025 ​ 1,214 ​ ​ ​ 2026 ​ 1,355 ​ ​ ​ 2027 ​ 1,396 ​ ​ ​ 2028 ​ ​ 1,438 ​ ​ ​ Thereafter ​ 1,857 ​ ​ ​ Total future minimum payments ​ $ 7,544 ​ ​ ​ Less: present value discount ​ ​ (1,424) ​ ​ ​ Present value of lease liabilities ​ $ 6,120 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
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, 2023 6,817,102 ​ $ 8.83 7.3 ​ $ 52 Granted ​ 2,974,950 ​ $ 1.65 ​ — ​ ​ — Exercised ​ (14,585) ​ $ 1.55 ​ — ​ ​ — Forfeitures ​ (885,459) ​ $ 3.43 ​ — ​ ​ — Outstanding as of September 30, 2024 ​ 8,892,008 ​ $ 6.98 ​ 7.3 ​ ​ 303 Exercisable as of September 30, 2024 4,844,594 ​ $ 10.82 6.0 ​ $ 101 (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 December 31, 2023 and September 30, 2024.
Summary of stock based compensation expense recorded	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ (in thousands) 2024 2023 2024 2023 ​ Research and development ​ $ 689 ​ $ 721 ​ $ 2,072 ​ $ 2,184 ​ General and administrative ​ 840 ​ 1,280 ​ 2,744 ​ 4,020 ​ Total stock-based compensation expense ​ $ 1,529 ​ $ 2,001 ​ $ 4,816 ​ $ 6,204 ​
Summary of assumptions used in the Black Scholes option pricing model for stock options granted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, ​ ​ 2024 2023 ​ Expected term 5.8 years ​ 6.1 years ​ Expected volatility 83.3 % ​ 81.4 % ​ Risk free interest rate 4.1 % ​ 3.5 - 4.1 % ​ Expected dividend yield — % ​ — % ​

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2024
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, ​ ​ 2024 2023 2024 2023 ​ Net loss (Numerator): ​ ​ ​ ​ ​ ​ Net loss - basic and diluted ​ $ (11,540) ​ $ (14,301) ​ $ (44,051) ​ $ (48,256) ​ Shares (Denominator): ​ ​ ​ ​ ​ Weighted-average shares outstanding - basic and diluted ​ 27,975,840 ​ 27,839,968 ​ 27,950,634 ​ 27,814,655 ​ Loss per share - basic and diluted ​ $ (0.41) ​ $ (0.51) ​ $ (1.58) ​ $ (1.73) ​
Summary of shares excluded from the computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ 2024 2023 Outstanding options to purchase common stock ​ 8,892,008 ​ 6,913,348 Total ​ 8,892,008 ​ 6,913,348 ​

Nature of the Business - Liquid

Nature of the Business - Liquidity (Details) $ in Millions	Sep. 30, 2024 USD ($)
Nature of the Business
Cash, cash equivalents and marketable securities	$ 75.3

Marketable Securities - (Detail

Marketable Securities - (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Investments
Amortized Cost	$ 47,530,000		$ 47,530,000		$ 95,439,000
Gross Unrealized Gain	78,000		78,000		41,000
Gross Unrealized Loss	(2,000)		(2,000)		(263,000)
Estimated Fair Value	47,606,000		47,606,000		95,217,000
Unrealized losses in a continuous loss position for more than twelve consecutive months	0		0
Gross realized gains	0	$ 0	0	$ 0
Fair market value of investments in unrealized loss position	6,600,000		6,600,000
Accrued interest receivable	$ 300,000		$ 300,000		$ 800,000
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Current, Statement of Financial Position [Extensible Enumeration]	Prepaid Expense and Other Assets, Current		Prepaid Expense and Other Assets, Current		Prepaid Expense and Other Assets, Current
Cost Maturities:
Within 1 year	$ 40,992,000		$ 40,992,000
Over 1 year	6,538,000		6,538,000
Total investments available for sale	47,530,000		47,530,000
Fair Value Maturities:
Within 1 year	41,042,000		41,042,000
Over 1 year	6,564,000		6,564,000
Total investments available for sale	47,606,000		47,606,000
Corporate bonds
Investments
Amortized Cost	39,586,000		39,586,000		$ 73,334,000
Gross Unrealized Gain	72,000		72,000		36,000
Gross Unrealized Loss	(2,000)		(2,000)		(210,000)
Estimated Fair Value	39,656,000		39,656,000		73,160,000
U.S. Treasury and Government agencies
Investments
Amortized Cost	7,944,000		7,944,000		22,105,000
Gross Unrealized Gain	6,000		6,000		5,000
Gross Unrealized Loss					(53,000)
Estimated Fair Value	$ 7,950,000		$ 7,950,000		$ 22,057,000

Fair Value Measurements - (Deta

Fair Value Measurements - (Details) - USD ($)	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Fair value of the Company's financial assets
Marketable Securities	$ 47,606,000	$ 95,217,000
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	39,656,000	73,160,000
U.S. Treasury and Government agencies
Fair value of the Company's financial assets
Marketable Securities	7,950,000	22,057,000
Fair Value
Fair value of the Company's financial assets
Total financial assets	74,952,000	107,799,000
Fair Value | Money market funds (cash equivalents)
Fair value of the Company's financial assets
Money market funds (cash equivalents)	27,346,000	12,582,000
Fair Value | Corporate bonds
Fair value of the Company's financial assets
Marketable Securities	39,656,000	73,160,000
Fair Value | U.S. Government agencies
Fair value of the Company's financial assets
Marketable Securities		22,057,000
Fair Value | U.S. Treasury and Government agencies
Fair value of the Company's financial assets
Marketable Securities	7,950,000
Fair Value | Quoted Prices in Active Markets (Level 1)
Fair value of the Company's financial assets
Total financial assets	27,346,000	12,582,000
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)	27,346,000	12,582,000
Fair Value | Significant Other Observable Inputs (Level 2)
Fair value of the Company's financial assets
Total financial assets	47,606,000	95,217,000
Fair Value | Significant Other Observable Inputs (Level 2) | Corporate bonds
Fair value of the Company's financial assets
Marketable Securities	39,656,000	73,160,000
Fair Value | Significant Other Observable Inputs (Level 2) | U.S. Government agencies
Fair value of the Company's financial assets
Marketable Securities		$ 22,057,000
Fair Value | Significant Other Observable Inputs (Level 2) | U.S. Treasury and Government agencies
Fair value of the Company's financial assets
Marketable Securities	$ 7,950,000

Leases - Other Information (Det

Leases - Other Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Leases
Lease extension period	5 years		5 years
Lessee, Operating Lease, Existence of Option to Extend [true false]			true
Operating lease expense	$ 253,000	$ 272,000	$ 779,000	$ 816,000
Operating cash flows used for operating leases			$ 843,000	$ 757,000
Weighted=average remaining lease term	5 years 6 months		5 years 6 months
Weighted average discount rate (as a percent)	7.47%		7.47%

Leases - Maturities (Details)

Leases - Maturities (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Future minimum lease payments
2024	$ 284
2025	1,214
2026	1,355
2027	1,396
2028	1,438
Thereafter	1,857
Total future minimum payments	7,544
Less: present value discount	(1,424)
Present value of lease liabilities	$ 6,120

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended		12 Months Ended	65 Months Ended
	May 03, 2019	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Sep. 30, 2024
2015 Plan
Number of Shares
Outstanding at the beginning (in shares)		6,817,102
Granted (in shares)		2,974,950
Exercised (in shares)		(14,585)
Forfeitures (in shares)		(885,459)
Outstanding at the end (in shares)		8,892,008		6,817,102	8,892,008
Exercisable at the end (in shares)		4,844,594			4,844,594
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)		$ 8.83
Granted (in dollars per share)		1.65
Exercised (in dollars per share)		1.55
Forfeited (in dollars per share)		3.43
Outstanding at the end (in dollars per share)		6.98		$ 8.83	$ 6.98
Exercisable at the end (in dollars per share)		$ 10.82			$ 10.82
Weighted Average Remaining Contractual Life (Years) And Aggregate Intrinsic Value
Outstanding (in years)		7 years 3 months 18 days		7 years 3 months 18 days
Exercisable at the end (in years)		6 years
Outstanding at the beginning (in dollars)		$ 52
Outstanding at the end (in dollars)		303		$ 52	$ 303
Exercisable at the end (in dollars)		$ 101			101
Weighted average grant date fair value per share of stock options granted		$ 1.19
Aggregate grant date fair value		$ 4,000	$ 7,200
Share Based Compensation Expense Not Recognized
Unrecognized compensation cost		$ 5,400			$ 5,400
Compensation expense recognition period		1 year 7 months 6 days
Omnibus Incentive Plan
Stock Based Compensation
Total number of shares of common stock that may be issued		2,900,000			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		1,221,931			1,221,931
2019 Employee Stock Purchase Plan
Stock Based Compensation
Number of shares issued					214,094
Number of shares reserved for issuance under the plan		855,616			855,616

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Stock based compensation expense
Total stock-based compensation expense	$ 1,529	$ 2,001	$ 4,816	$ 6,204
Research and development
Stock based compensation expense
Total stock-based compensation expense	689	721	2,072	2,184
General and administrative
Stock based compensation expense
Total stock-based compensation expense	$ 840	$ 1,280	$ 2,744	$ 4,020

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions (Details)	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Fair value assumptions
Expected term	5 years 9 months 18 days
Expected volatility	83.30%	81.40%
Risk free interest rate	4.10%
Minimum
Fair value assumptions
Expected term		6 years 1 month 6 days
Risk free interest rate		3.50%
Maximum
Fair value assumptions
Risk free interest rate		4.10%

Collaboration Agreements (Detai

Collaboration Agreements (Details) - Research Collaboration and Co-Development Agreement $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2022 item	Sep. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)
Collaboration Agreements
Collaboration agreements cost sharing percentage (as a percent)		50%		50%
LigaChem Biosciences
Collaboration Agreements
Maximum number of antibody drug conjugates to be developed | item	3
Collaboration agreements cost sharing percentage (as a percent)	50%
Collaboration arrangement reduction in expenses		$ 0.3	$ 1.6	$ 1.7
Additional receivable on collaboration agreements, finalization of cost sharing		$ 0.5		$ 0.5

Restructuring and Asset Impai_2

Restructuring and Asset Impairment (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Mar. 19, 2024	Mar. 31, 2024	Sep. 30, 2024
Restructuring and Asset Impairment
Asset impairment		$ 1,800	$ 1,786
Cost Reduction Plan
Restructuring and Asset Impairment
Percent of workforce reduction	37%
Severance costs			$ 800

Restructuring and Asset Impai_3

Restructuring and Asset Impairment - Activity for accrued severance costs (Details) - Employee severance - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2024	Sep. 30, 2024
Activity for accrued severance costs
Cash payments	$ (0.8)
Severance accrual		$ 0

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, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Income loss (Numerator):
Net loss - basic and diluted	$ (11,540)	$ (15,404)	$ (17,107)	$ (14,301)	$ (17,859)	$ (16,096)	$ (44,051)	$ (48,256)
Shares (Denominator):
Weighted-average shares for basic EPS (in shares)	27,975,840			27,839,968			27,950,634	27,814,655
Weighted-average shares for diluted EPS (in shares)	27,975,840			27,839,968			27,950,634	27,814,655
Basic EPS (in dollars per share)	$ (0.41)			$ (0.51)			$ (1.58)	$ (1.73)
Diluted EPS (in dollars per share)	$ (0.41)			$ (0.51)			$ (1.58)	$ (1.73)

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Anti-dilutive effect (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities
Antidilutive securities excluded from computation of diluted net loss per share	8,892,008	6,913,348
Employee Stock Option
Antidilutive Securities
Antidilutive securities excluded from computation of diluted net loss per share	8,892,008	6,913,348

Income Taxes - (Details)

Income Taxes - (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Taxes
Provision or benefit from income taxes	$ 0	$ 0	$ 0	$ 0