NextCure (NXTC) 10-Q 4 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 03, 2021
Cover Abstract
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-38905
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		27,626,227
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 36,664	$ 32,772
Marketable securities	198,672	250,676
Restricted cash	39	1,706
Prepaid expenses and other current assets	7,661	2,824
Total current assets	243,036	287,978
Property and equipment, net	14,208	15,809
Other assets	581	2,857
Total assets	257,825	306,644
Current liabilities:
Accounts payable	2,946	3,901
Accrued liabilities	4,232	4,627
Deferred rent, current portion	198	130
Term loan, current portion		1,667
Total current liabilities	7,376	10,325
Deferred rent, net of current portion	2,223	792
Term loan, net of current portion		1,806
Total liabilities	9,599	12,923
Stockholders' equity
Preferred stock; par value of $0.001 per share; 10,000,000 shares authorized at September 30, 2021 and December 31, 2020, no shares issued and outstanding at September 30, 2021 and December 31, 2020
Common stock, par value of $0.001 per share; 100,000,000 shares authorized at September 30, 2021 and December 31, 2020; 27,619,763 and 27,568,802 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	28	28
Additional paid-in capital	418,414	410,551
Accumulated other comprehensive (loss) income	(129)	779
Accumulated deficit	(170,087)	(117,637)
Total stockholders' equity	248,226	293,721
Total liabilities and stockholders' equity	$ 257,825	$ 306,644

CONDENSED BALANCE SHEETS - (Par

CONDENSED BALANCE SHEETS - (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
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	27,619,763	27,568,802
Common stock, shares outstanding	27,619,763	27,568,802

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
Revenue from former research and development arrangement				$ 22,378
Revenue, Product and Service [Extensible List]			us-gaap:TechnologyServiceMember
Operating expenses:
Research and development	$ 13,597	$ 12,740	$ 37,928	34,448
General and administrative	4,911	4,659	15,766	12,918
Total operating expenses	18,508	17,399	53,694	47,366
(Loss) from operations	(18,508)	(17,399)	(53,694)	(24,988)
Other income, net	578	1,032	1,244	3,846
Net loss	$ (17,930)	$ (16,367)	$ (52,450)	$ (21,142)
(Loss) earnings per share
Basic (in dollars per share)	$ (0.65)	$ (0.59)	$ (1.90)	$ (0.77)
Diluted (in dollars per share)	$ (0.65)	$ (0.59)	$ (1.90)	$ (0.77)
Weighted average shares outstanding - basic and diluted
Basic (in shares)	27,615,038	27,547,737	27,607,685	27,524,350
Diluted (in shares)	27,615,038	27,547,737	27,607,685	27,524,350
Comprehensive loss:
Net loss	$ (17,930)	$ (16,367)	$ (52,450)	$ (21,142)
Unrealized gain (loss) on marketable securities	66	(637)	(908)	1,298
Total comprehensive loss	$ (17,864)	$ (17,004)	$ (53,358)	$ (19,844)

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, 2019	$ 27	$ 402,529	$ (38)	$ (81,034)	$ 321,484
Balance at the beginning (in shares) at Dec. 31, 2019	27,499,260
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		1,008			1,008
Exercise of stock options	$ 1	36			37
Exercise of stock options (in shares)	17,142
Unrealized gain (loss) on marketable securities, net of tax $0			(505)		(505)
Net loss				9,733	9,733
Balance at the end at Mar. 31, 2020	$ 28	403,573	(543)	(71,301)	331,757
Balance at the end (in shares) at Mar. 31, 2020	27,516,402
Balance at the beginning at Dec. 31, 2019	$ 27	402,529	(38)	(81,034)	321,484
Balance at the beginning (in shares) at Dec. 31, 2019	27,499,260
Increase (Decrease) in Stockholders' Deficit
Net loss					(21,142)
Balance at the end at Sep. 30, 2020	$ 28	408,189	1,298	(102,176)	307,339
Balance at the end (in shares) at Sep. 30, 2020	27,553,089
Balance at the beginning at Mar. 31, 2020	$ 28	403,573	(543)	(71,301)	331,757
Balance at the beginning (in shares) at Mar. 31, 2020	27,516,402
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,187			2,187
Exercise of stock options		3			3
Exercise of stock options (in shares)	4,248
Unrealized gain (loss) on marketable securities, net of tax $0			2,478		2,478
Net loss				(14,508)	(14,508)
Balance at the end at Jun. 30, 2020	$ 28	405,763	1,935	(85,809)	321,917
Balance at the end (in shares) at Jun. 30, 2020	27,520,650
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,372			2,372
Exercise of stock options		54			54
Exercise of stock options (in shares)	32,439
Unrealized gain (loss) on marketable securities, net of tax $0			(637)		(637)
Net loss				(16,367)	(16,367)
Balance at the end at Sep. 30, 2020	$ 28	408,189	1,298	(102,176)	307,339
Balance at the end (in shares) at Sep. 30, 2020	27,553,089
Balance at the beginning at Dec. 31, 2020	$ 28	410,551	779	(117,637)	$ 293,721
Balance at the beginning (in shares) at Dec. 31, 2020	27,568,802				27,568,802
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,508			$ 2,508
Exercise of stock options		63			63
Exercise of stock options (in shares)	35,615
Unrealized gain (loss) on marketable securities, net of tax $0			(600)		(600)
Net loss				(16,533)	(16,533)
Balance at the end at Mar. 31, 2021	$ 28	413,122	179	(134,170)	279,159
Balance at the end (in shares) at Mar. 31, 2021	27,604,417
Balance at the beginning at Dec. 31, 2020	$ 28	410,551	779	(117,637)	$ 293,721
Balance at the beginning (in shares) at Dec. 31, 2020	27,568,802				27,568,802
Increase (Decrease) in Stockholders' Deficit
Net loss					$ (52,450)
Balance at the end at Sep. 30, 2021	$ 28	418,414	(129)	(170,087)	$ 248,226
Balance at the end (in shares) at Sep. 30, 2021	27,619,763				27,619,763
Balance at the beginning at Mar. 31, 2021	$ 28	413,122	179	(134,170)	$ 279,159
Balance at the beginning (in shares) at Mar. 31, 2021	27,604,417
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,787			2,787
Exercise of stock options		13			13
Exercise of stock options (in shares)	7,138
Unrealized gain (loss) on marketable securities, net of tax $0			(374)		(374)
Net loss				(17,987)	(17,987)
Balance at the end at Jun. 30, 2021	$ 28	415,922	(195)	(152,157)	263,598
Balance at the end (in shares) at Jun. 30, 2021	27,611,555
Increase (Decrease) in Stockholders' Deficit
Stock based compensation		2,483			2,483
Exercise of stock options		9			9
Exercise of stock options (in shares)	8,208
Unrealized gain (loss) on marketable securities, net of tax $0			66		66
Net loss				(17,930)	(17,930)
Balance at the end at Sep. 30, 2021	$ 28	$ 418,414	$ (129)	$ (170,087)	$ 248,226
Balance at the end (in shares) at Sep. 30, 2021	27,619,763				27,619,763

CONDENSED STATEMENTS OF STOCK_2

CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY
Unrealized loss on marketable securities, tax	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (52,450)	$ (21,142)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, amortization and other	5,093	2,423
Stock-based compensation	7,778	5,567
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(4,365)	(690)
Accounts payable	(955)	(1,675)
Accrued liabilities	(395)	(1,117)
Deferred rent	1,499	336
Deferred revenue		(22,378)
Net cash used in operating activities	(43,795)	(38,676)
Cash flows from investing activities:
Maturities of marketable securities	171,037	129,169
Purchase of marketable securities	(121,900)	(95,992)
Purchase of property and equipment	(1,535)	(6,152)
Net cash provided by investing activities	47,602	27,025
Cash flows from financing activities:
Proceeds from exercise of stock options	85	94
Payments of the term loan	(3,473)	(1,111)
Net cash used in financing activities	(3,388)	(1,017)
Net increase (decrease) in cash, cash equivalents and restricted cash	419	(12,668)
Cash, cash equivalents and restricted cash - beginning of period	36,284	39,130
Cash, cash equivalents and restricted cash - end of period	36,703	26,462
Supplemental disclosures of cash flow information:
Cash paid for interest	$ 139	130
Supplemental disclosures of noncash investing and financing activities:
Purchase of property and equipment included in accrued liabilities		$ 134

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2021
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, 2021, 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 (see Note 6). The Company expects to incur additional operating losses and negative operating cash flows for the foreseeable future. Risks and Uncertainties COVID-19 In March 2020, the World Health Organization declared the novel coronavirus disease 2019 (“COVID-19”), outbreak a pandemic. In order to mitigate the spread of COVID-19, governments have imposed unprecedented restrictions on business operations, travel, and gatherings, resulting in a global economic downturn and other adverse economic and societal impacts. The COVID-19 pandemic has also overwhelmed or otherwise led to changes in the operations of many healthcare facilities, including clinical trial sites. However, the Company’s laboratories have continued operations throughout the pandemic mostly without interruption. The impact of the COVID-19 pandemic (including the impact of emerging variant strains of the COVID-19 virus) on the Company’s business and financial performance is uncertain and depends on various factors, including the scope and duration of the pandemic, the efficacy and global distribution of vaccines, government restrictions and other actions, including relief measures, implemented to address the impact of the pandemic, and resulting impacts on the financial markets and overall economy. The imposition of “lockdown,” “social distancing” and “shelter in place” directives and other restrictions on business operations, travel and gatherings by state and federal governments in the United States, as well as governments in other regions of the world in response to the COVID-19 pandemic, has placed significant strain on the Company’s clinical trial sites, has raised concerns around monitoring patient safety, and has caused enrollment to slow in the Company’s clinical trials. Any rise of COVID-19 infection rates, especially in the United States, could continue to negatively affect enrollment going forward. The Company continues to closely monitor the COVID-19 situation and any potential impact to the Company’s planned activities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies There have been no material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. Basis of Presentation The unaudited condensed financial statements include the accounts of NextCure 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 Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (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. In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02 (Topic 842), Leases (“ASC 842”). ASC 842 supersedes the lease recognition requirements in ASC 840, Leases. ASC 842 clarifies the definition of a lease and requires lessees to recognize right-of-use assets and lease liabilities for all leases, including those classified as operating leases under previous lease accounting guidance. For public entities, ASC 842 was effective for fiscal years beginning after December 15, 2018, including interim periods within that year. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASC 842 will be effective for the Company on January 1, 2022. Originally, entities were required to adopt ASC 842 using a modified retrospective transition method. However, in July 2018, the FASB issued ASU 2018-11 (Topic 842), Leases: Targeted Improvements, which provides entities with an additional transition method. Under ASU 2018-11, entities have the option of initially applying ASC 842 at the adoption date, rather than at the beginning of the earliest period presented and recognizing the cumulative effect of applying the new standard as an adjustment to beginning retained earnings in the year of adoption while continuing to present all prior periods under previous lease accounting guidance. The Company is currently evaluating the impact of adopting this guidance on the Company’s financial statements. The Company currently expects that its operating lease commitments will be subject to the new standard and recognized as right-of-use assets and operating lease liabilities upon adoption of this standard, which will increase the total assets and total liabilities that it reports relative to such amounts presented prior to adoption. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 will require credit losses to be reported using an expected losses model rather than the incurred losses model that is currently used and will require additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, this standard will require allowances to be recorded instead of reducing the amortized cost of the investment. ASU 2016-13 is effective for non-EGCs for fiscal years beginning December 15, 2019, and interim periods within those fiscal years, and will be effective for the Company for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years, assuming the Company remains an EGC. The Company adopted this standard early, effective January 1, 2021. The adoption of this standard did not have a material impact on the Company’s financial statements. The Company considers the applicability and impact of all ASUs issued by the 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.

Restricted Cash

Restricted Cash	9 Months Ended
	Sep. 30, 2021
Restricted Cash.
Restricted Cash	3. Restricted Cash In August 2021, the Company fully paid the remaining principal balance of $2.4 million of its $5.0 million term loan (the “Term Loan”). As a result of this payment, the Company has no restricted cash held in support of the Term Loan. The required Term Loan reserve totaled $0 and $3.5 million as of September 30, 2021 and December 31, 2020, respectively. These amounts are presented in part as restricted cash and in part as other assets on the accompanying condensed balance sheets. The following table reconciles cash and cash equivalents and restricted cash per the balance sheet to the condensed statement of cash flows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, (in thousands) 2021 2020 ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 36,664 ​ $ 32,772 Restricted cash (including $0 and $1,806 in other assets as of September 30, 2021 and December 31, 2020, respectively) ​ 39 ​ 3,512 Total ​ $ 36,703 ​ $ 36,284 ​

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2021
Marketable Securities
Marketable Securities	4. Marketable Securities Marketable securities consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 198,801 ​ $ 43 ​ $ (172) ​ $ 198,672 Total ​ $ 198,801 ​ $ 43 ​ $ (172) ​ $ 198,672 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 242,900 ​ $ 854 ​ $ (75) ​ $ 243,679 Commercial paper ​ 6,997 ​ — ​ — ​ 6,997 Total ​ $ 249,897 ​ $ 854 ​ $ (75) ​ $ 250,676 ​ ​ The Company uses the specific identification method when calculating realized gains and losses. For the nine months ended September 30, 2021 and 2020, respectively, the Company recorded $57 thousand and $70 thousand 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. The Company has analyzed the unrealized losses and determined that market conditions were the primary factor driving these changes. After analyzing the securities in an unrealized loss position, the portion of these losses that relate 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, 2021 : ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ ​ ​ ​ Fair (in thousands) Cost Value Maturities: ​ ​ ​ ​ ​ ​ Within 1 year ​ $ 96,103 ​ $ 96,114 Between 1 to 2 years ​ 102,698 ​ 102,558 Total investments available for sale ​ $ 198,801 ​ $ 198,672 ​ ​ The Company has classified all its investments available-for-sale, 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
	Sep. 30, 2021
Fair Value Measurements
Fair Value Measurements	5. 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, 2021 and December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 21,271 ​ $ 21,271 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 198,672 ​ ​ — ​ ​ 198,672 ​ ​ — Total ​ $ 219,943 ​ $ 21,271 ​ $ 198,672 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 11,155 ​ $ 11,155 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 243,679 ​ ​ — ​ ​ 243,679 ​ ​ — Commercial paper ​ ​ 6,997 ​ ​ — ​ ​ 6,997 ​ ​ — Total ​ $ 261,831 ​ $ 11,155 ​ $ 250,676 ​ $ — ​ ​ The Company did not transfer any assets measured at fair value on a recurring basis between levels during the three and nine months ended September 30, 2021 and 2020.

Former Agreement with Eli Lilly

Former Agreement with Eli Lilly and Company	9 Months Ended
	Sep. 30, 2021
Former Agreement with Eli Lilly and Company
Former Agreement with Eli Lilly and Company	6. Former Agreement with Eli Lilly and Company On November 2, 2018, the Company entered into a multi-year research and development collaboration agreement (the “Lilly Agreement”) with Eli Lilly and Company (“Lilly”), pursuant to which the Company agreed to use its proprietary FIND-IO platform to identify novel oncology targets for additional collaborative research and drug discovery by the Company and Lilly. Effective March 3, 2020, Lilly terminated the Lilly Agreement without cause. The Company recognized revenue under the Lilly Agreement of $22.4 million for the nine months ended September 30, 2020. Effective with the termination of the agreement, no further quarterly research and development support payments are payable to the Company. ​

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2021
Stock-Based Compensation
Stock-Based Compensation	7. 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. The number of shares reserved for issuance under the 2019 Plan automatically increase each January 1st during the term of the 2019 Plan by 4% of the number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year or such lesser number of shares determined by the Board. As of September 30, 2021, 2,369,673 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, 2020 3,112,376 ​ $ 16.95 8.2 ​ $ 10,810 Granted ​ 1,916,450 ​ $ 11.11 ​ — ​ ​ — Exercised ​ (50,961) ​ $ 1.66 ​ — ​ ​ — Forfeited ​ (433,483) ​ $ 21.82 ​ — ​ ​ — Outstanding as of September 30, 2021 ​ 4,544,382 ​ $ 14.20 ​ 8.3 ​ $ 3,606 Exercisable as of September 30, 2021 1,848,180 ​ $ 12.19 7.2 ​ $ 3,405 (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, 2021 and December 31, 2020. The weighted average grant date fair value of stock options granted to employees for the nine months ended September 30, 2021 was $7.61. The aggregate intrinsic value of stock options exercised during the nine months ended September 30, 2021 was $0.3 million. As of September 30, 2021, there was $25.7 million of total unrecognized compensation expense related to unvested options under the Plans that will be recognized over a weighted-average period of approximately 2.9 years. The aggregate grant date fair value of stock options and restricted stock vested during the nine months ended September 30, 2021 and 2020 was approximately $11.9 million and $33.8 million, respectively. Stock-based compensation expense was classified on the statements of operations as follows for the three and nine months ended September 30, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ (in thousands) 2021 2020 2021 2020 ​ Research and development ​ $ 1,054 ​ $ 897 ​ $ 3,068 ​ $ 2,245 ​ General and administrative ​ 1,429 ​ 1,475 ​ 4,710 ​ 3,322 ​ Total stock-based compensation expense ​ $ 2,483 ​ $ 2,372 ​ $ 7,778 ​ $ 5,567 ​ ​ ​ 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, ​ ​ 2021 2020 ​ Expected term 5.5 - 6.08 years ​ 5.4 - 6.08 years ​ Expected volatility 79.7 % ​ 69.7 - 81.1 % ​ Risk free interest rate 0.8 - 1.4 % ​ 0.3 - 1.0 % ​ 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 certain employees of the Company to purchase shares of Company stock at a discounted price. As of September 30, 2021, 790,680 shares were reserved for purchase under the ESPP.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2021
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 Loss per share 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 stock option 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, ​ 2021 2020 2021 2020 Net loss (Numerator): ​ ​ ​ ​ ​ ​ Net loss - basic and diluted ​ $ (17,930) ​ $ (16,367) ​ $ (52,450) ​ $ (21,142) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares (Denominator): ​ ​ ​ ​ Weighted-average shares outstanding - basic and diluted ​ 27,615,038 ​ 27,547,737 ​ 27,607,685 ​ 27,524,350 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss per share - basic and diluted ​ $ (0.65) ​ $ (0.59) ​ $ (1.90) ​ $ (0.77) ​ ​ For the three and nine months ended September 30, 2021, all shares of 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, ​ 2021 2020 Outstanding options to purchase common stock ​ 4,544,382 ​ 3,149,641 Total ​ 4,544,382 ​ 3,149,641 ​

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Taxes
Income Taxes	9. Income Taxes The Company did not record a provision or benefit for income taxes during the three and nine months ended September 30, 2021 and 2020. 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 (“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. On March 27, 2020, the Coronavirus Aid, Relief and Economic Security Act (the “CARES Act”) was signed into law. The CARES Act includes various income and payroll tax provisions. The Company has analyzed the tax provisions of the CARES Act and determined they have no significant financial impact to the Company’s condensed financial statements. On March 11, 2021, the American Rescue Plan Act of 2021 (“ARPA 2021”) was signed into law. ARPA 2021 included various income and payroll tax provisions. The Company has analyzed the tax provisions of ARPA 2021 and determined they have no significant financial impact to the Company’s condensed financial statements.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
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.). 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, with respect to statements made regarding our lead product candidate, NC318, 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 discovery is stayed pending resolution of that motion. 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, 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 of 1933. 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 derivative lawsuit pending resolution of the Ye Zhou action’s motion to dismiss. The Company intends to vigorously defend the Ye Zhou and Liu actions and believes these cases are without merit. Based on the Company’s assessment of the facts underlying these claims, the uncertainty of litigation, and the preliminary stage of these cases, the Company cannot estimate the reasonably possible loss or range of loss that may result from these actions.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Summary of Significant Accounting Policies
Basis of Presentation and Unaudited Financial Information	Basis of Presentation The unaudited condensed financial statements include the accounts of NextCure 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 Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (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. In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02 (Topic 842), Leases (“ASC 842”). ASC 842 supersedes the lease recognition requirements in ASC 840, Leases. ASC 842 clarifies the definition of a lease and requires lessees to recognize right-of-use assets and lease liabilities for all leases, including those classified as operating leases under previous lease accounting guidance. For public entities, ASC 842 was effective for fiscal years beginning after December 15, 2018, including interim periods within that year. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASC 842 will be effective for the Company on January 1, 2022. Originally, entities were required to adopt ASC 842 using a modified retrospective transition method. However, in July 2018, the FASB issued ASU 2018-11 (Topic 842), Leases: Targeted Improvements, which provides entities with an additional transition method. Under ASU 2018-11, entities have the option of initially applying ASC 842 at the adoption date, rather than at the beginning of the earliest period presented and recognizing the cumulative effect of applying the new standard as an adjustment to beginning retained earnings in the year of adoption while continuing to present all prior periods under previous lease accounting guidance. The Company is currently evaluating the impact of adopting this guidance on the Company’s financial statements. The Company currently expects that its operating lease commitments will be subject to the new standard and recognized as right-of-use assets and operating lease liabilities upon adoption of this standard, which will increase the total assets and total liabilities that it reports relative to such amounts presented prior to adoption. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 will require credit losses to be reported using an expected losses model rather than the incurred losses model that is currently used and will require additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, this standard will require allowances to be recorded instead of reducing the amortized cost of the investment. ASU 2016-13 is effective for non-EGCs for fiscal years beginning December 15, 2019, and interim periods within those fiscal years, and will be effective for the Company for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years, assuming the Company remains an EGC. The Company adopted this standard early, effective January 1, 2021. The adoption of this standard did not have a material impact on the Company’s financial statements. The Company considers the applicability and impact of all ASUs issued by the 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.

Restricted Cash (Tables)

Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2021
Restricted Cash.
Summary of reconciliation cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, (in thousands) 2021 2020 ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 36,664 ​ $ 32,772 Restricted cash (including $0 and $1,806 in other assets as of September 30, 2021 and December 31, 2020, respectively) ​ 39 ​ 3,512 Total ​ $ 36,703 ​ $ 36,284

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2021
Marketable Securities
Schedule of marketable securities	Marketable securities consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 198,801 ​ $ 43 ​ $ (172) ​ $ 198,672 Total ​ $ 198,801 ​ $ 43 ​ $ (172) ​ $ 198,672 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (in thousands) Cost Gain Loss Fair Value Corporate bonds ​ $ 242,900 ​ $ 854 ​ $ (75) ​ $ 243,679 Commercial paper ​ 6,997 ​ — ​ — ​ 6,997 Total ​ $ 249,897 ​ $ 854 ​ $ (75) ​ $ 250,676
Schedule of available-for-sale maturities	The following table summarizes maturities of the Company’s investments available-for-sale as of September 30, 2021 : ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ ​ ​ ​ Fair (in thousands) Cost Value Maturities: ​ ​ ​ ​ ​ ​ Within 1 year ​ $ 96,103 ​ $ 96,114 Between 1 to 2 years ​ 102,698 ​ 102,558 Total investments available for sale ​ $ 198,801 ​ $ 198,672

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
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, 2021 and December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 21,271 ​ $ 21,271 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 198,672 ​ ​ — ​ ​ 198,672 ​ ​ — Total ​ $ 219,943 ​ $ 21,271 ​ $ 198,672 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 11,155 ​ $ 11,155 ​ $ — ​ $ — Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ ​ 243,679 ​ ​ — ​ ​ 243,679 ​ ​ — Commercial paper ​ ​ 6,997 ​ ​ — ​ ​ 6,997 ​ ​ — Total ​ $ 261,831 ​ $ 11,155 ​ $ 250,676 ​ $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
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, 2020 3,112,376 ​ $ 16.95 8.2 ​ $ 10,810 Granted ​ 1,916,450 ​ $ 11.11 ​ — ​ ​ — Exercised ​ (50,961) ​ $ 1.66 ​ — ​ ​ — Forfeited ​ (433,483) ​ $ 21.82 ​ — ​ ​ — Outstanding as of September 30, 2021 ​ 4,544,382 ​ $ 14.20 ​ 8.3 ​ $ 3,606 Exercisable as of September 30, 2021 1,848,180 ​ $ 12.19 7.2 ​ $ 3,405 (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, 2021 and December 31, 2020.
Summary of stock based compensation expense recorded	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ (in thousands) 2021 2020 2021 2020 ​ Research and development ​ $ 1,054 ​ $ 897 ​ $ 3,068 ​ $ 2,245 ​ General and administrative ​ 1,429 ​ 1,475 ​ 4,710 ​ 3,322 ​ Total stock-based compensation expense ​ $ 2,483 ​ $ 2,372 ​ $ 7,778 ​ $ 5,567 ​
Summary of assumptions used in the Black Scholes option pricing model for stock options granted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, ​ ​ 2021 2020 ​ Expected term 5.5 - 6.08 years ​ 5.4 - 6.08 years ​ Expected volatility 79.7 % ​ 69.7 - 81.1 % ​ Risk free interest rate 0.8 - 1.4 % ​ 0.3 - 1.0 % ​ Expected dividend yield — % ​ — % ​

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2021
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, ​ 2021 2020 2021 2020 Net loss (Numerator): ​ ​ ​ ​ ​ ​ Net loss - basic and diluted ​ $ (17,930) ​ $ (16,367) ​ $ (52,450) ​ $ (21,142) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares (Denominator): ​ ​ ​ ​ Weighted-average shares outstanding - basic and diluted ​ 27,615,038 ​ 27,547,737 ​ 27,607,685 ​ 27,524,350 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss per share - basic and diluted ​ $ (0.65) ​ $ (0.59) ​ $ (1.90) ​ $ (0.77)
Summary of shares excluded from the computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ 2021 2020 Outstanding options to purchase common stock ​ 4,544,382 ​ 3,149,641 Total ​ 4,544,382 ​ 3,149,641

Restricted Cash (Details)

Restricted Cash (Details) - USD ($)	1 Months Ended
	Aug. 31, 2021	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Restricted Cash
Face amount		$ 5,000,000
Restricted cash required reserve		0	$ 3,500,000
Reconciliation of cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows
Repayment of principal debt balance	$ 2,400,000
Cash and cash equivalents		36,664,000	32,772,000
Restricted cash (including $0 and $1,806 in other assets as of September 30, 2021 and December 31, 2020, respectively)		39,000	3,512,000
Total		36,703,000	36,284,000	$ 26,462,000	$ 39,130,000
Other assets, restricted cash		$ 0	$ 1,806,000

Marketable Securities - (Detail

Marketable Securities - (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Investments
Amortized Cost	$ 198,801		$ 249,897
Gross Unrealized Gain	43		854
Gross Unrealized Loss	(172)		(75)
Estimated Fair Value	198,672		250,676
Gross realized gains	57	$ 70
Cost Maturities:
Within 1 year	96,103
Between 1 to 2 years	102,698
Total investments available for sale	198,801
Fair Value Maturities:
Within 1 year	96,114
Between 1 to 2 years	102,558
Total investments available for sale	198,672
Corporate bonds
Investments
Amortized Cost	198,801		242,900
Gross Unrealized Gain	43		854
Gross Unrealized Loss	(172)		(75)
Estimated Fair Value	$ 198,672		243,679
Commercial Paper
Investments
Amortized Cost			6,997
Estimated Fair Value			$ 6,997

Fair Value Measurements - (Deta

Fair Value Measurements - (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Fair value of the Company's financial assets
Marketable Securities	$ 198,672,000		$ 198,672,000		$ 250,676,000
Assets transferred into level 3	0	$ 0	0	$ 0
Assets transferred out of level 3	0	$ 0	0	$ 0
Fair Value
Fair value of the Company's financial assets
Total financial assets	219,943,000		219,943,000		261,831,000
Fair Value | Quoted Prices in Active Markets (Level 1)
Fair value of the Company's financial assets
Total financial assets	21,271,000		21,271,000		11,155,000
Fair Value | Significant Other Observable Inputs (Level 2)
Fair value of the Company's financial assets
Total financial assets	198,672,000		198,672,000		250,676,000
Money market funds (cash equivalents) | Fair Value
Fair value of the Company's financial assets
Money market funds (cash equivalents)	21,271,000		21,271,000		11,155,000
Money market funds (cash equivalents) | Fair Value | Quoted Prices in Active Markets (Level 1)
Fair value of the Company's financial assets
Money market funds (cash equivalents)	21,271,000		21,271,000		11,155,000
Corporate bonds | Fair Value
Fair value of the Company's financial assets
Marketable Securities	198,672,000		198,672,000		243,679,000
Corporate bonds | Fair Value | Significant Other Observable Inputs (Level 2)
Fair value of the Company's financial assets
Marketable Securities	$ 198,672,000		$ 198,672,000		243,679,000
Commercial Paper | Fair Value
Fair value of the Company's financial assets
Marketable Securities					6,997,000
Commercial Paper | Fair Value | Significant Other Observable Inputs (Level 2)
Fair value of the Company's financial assets
Marketable Securities					$ 6,997,000

Former Agreement with Eli Lil_2

Former Agreement with Eli Lilly and Company (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Collaborative Arrangements
Revenue from former research and development arrangement	$ 22,378
Lilly Agreement
Collaborative Arrangements
Revenue from former research and development arrangement	$ 22,400

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	May 03, 2019	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
2015 Plan
Number of Shares
Outstanding at the beginning (in shares)		3,112,376
Granted (in shares)		1,916,450
Exercised (in shares)		(50,961)
Forfeitures (in shares)		(433,483)
Outstanding at the end (in shares)		4,544,382		3,112,376
Exercisable at the end (in shares)		1,848,180
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)		$ 16.95
Granted (in dollars per share)		11.11
Exercised (in dollars per share)		1.66
Forfeited (in dollars per share)		21.82
Outstanding at the end (in dollars per share)		14.20		$ 16.95
Exercisable at the end (in dollars per share)		$ 12.19
Weighted Average Remaining Contractual Life (Years) And Aggregate Intrinsic Value
Outstanding (in years)		8 years 3 months 18 days		8 years 2 months 12 days
Exercisable at the end (in years)		7 years 2 months 12 days
Outstanding at the beginning (in dollars)		$ 10,810
Outstanding at the end (in dollars)		3,606		$ 10,810
Exercisable at the end (in dollars)		$ 3,405
Weighted average grant date fair value per share of stock options granted		$ 7.61
Aggregate intrinsic value of stock options exercised		$ 300
Aggregate grant date fair value		11,900	$ 33,800
Share Based Compensation Expense Not Recognized
Unrecognized compensation cost		$ 25,700
Compensation expense recognition period		2 years 10 months 24 days
Omnibus Incentive Plan
Stock Based Compensation
Number of shares reserved for issuance under the plan	2,900,000
Annual increase in number of share reserved for issuance (as percent)	4.00%
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		2,369,673
2019 Employee Stock Purchase Plan
Stock Based Compensation
Number of shares reserved for issuance under the plan		790,680

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock based compensation expense
Total stock-based compensation expense	$ 2,483	$ 2,372	$ 7,778	$ 5,567
Research and development
Stock based compensation expense
Total stock-based compensation expense	1,054	897	3,068	2,245
General and administrative
Stock based compensation expense
Total stock-based compensation expense	$ 1,429	$ 1,475	$ 4,710	$ 3,322

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions (Details)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Fair value assumptions
Expected volatility	79.70%
Minimum
Fair value assumptions
Expected term	5 years 6 months	5 years 4 months 24 days
Expected volatility		69.70%
Risk free interest rate	0.80%	0.30%
Maximum
Fair value assumptions
Expected term	6 years 29 days	6 years 29 days
Expected volatility		81.10%
Risk free interest rate	1.40%	1.00%

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, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Income (loss) (Numerator):
Net loss for basic and diluted	$ (17,930)	$ (17,987)	$ (16,533)	$ (16,367)	$ (14,508)	$ 9,733	$ (52,450)	$ (21,142)
Shares (Denominator):
Weighted-average number of common shares outstanding (in shares)	27,615,038			27,547,737			27,607,685	27,524,350
Weighted-average shares for diluted EPS (in shares)	27,615,038			27,547,737			27,607,685	27,524,350
Basic EPS (in dollars per share)	$ (0.65)			$ (0.59)			$ (1.90)	$ (0.77)
Diluted EPS (in dollars per share)	$ (0.65)			$ (0.59)			$ (1.90)	$ (0.77)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Anti-dilutive effect (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities
Antidilutive securities excluded from computation of diluted net loss per share	4,544,382	3,149,641
Option to purchase common stock
Antidilutive Securities
Antidilutive securities excluded from computation of diluted net loss per share	4,544,382	3,149,641

Income Taxes - (Details)

Income Taxes - (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Taxes
Provision or benefit from income taxes	$ 0	$ 0	$ 0	$ 0