Aprea Therapeutics (APRE) 10-Q 12 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 12, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2021
Entity File Number	001-39069
Entity Registrant Name	Aprea Therapeutics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-2246769
Entity Address, Address Line One	535 Boylston Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02116
City Area Code	617
Local Phone Number	463-9385
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	APRE
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	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		21,186,827
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001781983
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 69,803,845	$ 89,017,686
Prepaid expenses and other current assets	1,494,453	3,399,019
Total current assets	71,298,298	92,416,705
Property and equipment, net	30,955	38,515
Right of use lease asset	191,098	320,616
Other noncurrent assets	29,379	29,383
Total assets	71,549,730	92,805,219
Current liabilities:
Accounts payable	2,361,318	4,503,619
Accrued expenses	8,037,524	10,571,237
Lease liability-current	199,219	256,309
Total current liabilities	10,598,061	15,331,165
Lease liability-noncurrent		78,847
Total liabilities	10,598,061	15,410,012
Commitments and contingencies (Note 7)
Stockholders' equity:
Common stock, $0.001 par value, 400,000,000 shares authorized, 21,186,827 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	21,187	21,187
Additional paid-in capital	235,104,416	231,418,356
Accumulated other comprehensive loss	(10,247,091)	(10,037,261)
Accumulated deficit	(163,926,843)	(144,007,075)
Total stockholders' equity	60,951,669	77,395,207
Total liabilities and stockholders' equity	$ 71,549,730	$ 92,805,219

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	21,186,827	21,186,827
Common stock, shares outstanding	21,186,827	21,186,827

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating expenses:
Research and development	$ 6,654,257	$ 10,694,029	$ 13,418,105	$ 19,790,151
General and administrative	3,343,325	3,786,886	6,769,158	6,563,354
Total operating expenses	9,997,582	14,480,915	20,187,263	26,353,505
Other income (expense):
Interest (expense) income, net	(588)	2,678	(1,645)	227,120
Foreign currency (loss) gain	(252,843)	(1,889,690)	269,140	358,201
Total other (expense) income	(253,431)	(1,887,012)	267,495	585,321
Net loss	(10,251,013)	(16,367,927)	(19,919,768)	(25,768,184)
Other comprehensive loss:
Foreign currency translation	193,020	1,756,783	(209,830)	(667,870)
Total comprehensive loss	$ (10,057,993)	$ (14,611,144)	$ (20,129,598)	$ (26,436,054)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.48)	$ (0.78)	$ (0.94)	$ (1.22)
Weighted-average common shares outstanding, basic and diluted (in shares)	21,186,827	21,107,056	21,186,827	21,079,891

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock	Additional Paid-in capital	Accumulated other comprehensive loss	Accumulated deficit	Total
Equity, beginning balance at Dec. 31, 2019	$ 21,023	$ 226,284,548	$ (11,533,778)	$ (90,528,263)	$ 124,243,530
Equity, beginning balance (in shares) at Dec. 31, 2019	21,022,752
Increase (Decrease) in Stockholders' Equity
Exercise of stock options	$ 32	29,491			29,523
Exercise of stock options (in shares)	32,090
Stockbased compensation		905,471			905,471
Foreign currency translation			(2,424,653)		(2,424,653)
Net loss				(9,400,257)	(9,400,257)
Equity, ending balance at Mar. 31, 2020	$ 21,055	227,219,510	(13,958,431)	(99,928,520)	113,353,614
Equity, ending balance (in shares) at Mar. 31, 2020	21,054,842
Equity, beginning balance at Dec. 31, 2019	$ 21,023	226,284,548	(11,533,778)	(90,528,263)	124,243,530
Equity, beginning balance (in shares) at Dec. 31, 2019	21,022,752
Increase (Decrease) in Stockholders' Equity
Foreign currency translation					(667,870)
Net loss					(25,768,184)
Equity, ending balance at Jun. 30, 2020	$ 21,187	228,597,264	(12,201,648)	(116,296,447)	100,120,356
Equity, ending balance (in shares) at Jun. 30, 2020	21,186,827
Equity, beginning balance at Mar. 31, 2020	$ 21,055	227,219,510	(13,958,431)	(99,928,520)	113,353,614
Equity, beginning balance (in shares) at Mar. 31, 2020	21,054,842
Increase (Decrease) in Stockholders' Equity
Exercise of stock options	$ 132	121,294			121,426
Exercise of stock options (in shares)	131,985
Stockbased compensation		1,256,460			1,256,460
Foreign currency translation			1,756,783		1,756,783
Net loss				(16,367,927)	(16,367,927)
Equity, ending balance at Jun. 30, 2020	$ 21,187	228,597,264	(12,201,648)	(116,296,447)	100,120,356
Equity, ending balance (in shares) at Jun. 30, 2020	21,186,827
Equity, beginning balance at Dec. 31, 2020	$ 21,187	231,418,356	(10,037,261)	(144,007,075)	77,395,207
Equity, beginning balance (in shares) at Dec. 31, 2020	21,186,827
Increase (Decrease) in Stockholders' Equity
Stockbased compensation		1,822,562			1,822,562
Foreign currency translation			(402,850)		(402,850)
Net loss				(9,668,755)	(9,668,755)
Equity, ending balance at Mar. 31, 2021	$ 21,187	233,240,918	(10,440,111)	(153,675,830)	69,146,164
Equity, ending balance (in shares) at Mar. 31, 2021	21,186,827
Equity, beginning balance at Dec. 31, 2020	$ 21,187	231,418,356	(10,037,261)	(144,007,075)	77,395,207
Equity, beginning balance (in shares) at Dec. 31, 2020	21,186,827
Increase (Decrease) in Stockholders' Equity
Foreign currency translation					(209,830)
Net loss					(19,919,768)
Equity, ending balance at Jun. 30, 2021	$ 21,187	235,104,416	(10,247,091)	(163,926,843)	60,951,669
Equity, ending balance (in shares) at Jun. 30, 2021	21,186,827
Equity, beginning balance at Mar. 31, 2021	$ 21,187	233,240,918	(10,440,111)	(153,675,830)	69,146,164
Equity, beginning balance (in shares) at Mar. 31, 2021	21,186,827
Increase (Decrease) in Stockholders' Equity
Stockbased compensation		1,863,498			1,863,498
Foreign currency translation			193,020		193,020
Net loss				(10,251,013)	(10,251,013)
Equity, ending balance at Jun. 30, 2021	$ 21,187	$ 235,104,416	$ (10,247,091)	$ (163,926,843)	$ 60,951,669
Equity, ending balance (in shares) at Jun. 30, 2021	21,186,827

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (19,919,768)	$ (25,768,184)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	6,723	7,866
Stockbased compensation	3,686,060	2,161,931
Amortization of right of use lease asset	129,518	108,164
Foreign currency (gain)	(269,140)	(358,201)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,904,566	1,480,655
Accounts payable	(2,142,301)	3,266,274
Accrued expenses and other liabilities	(2,533,713)	2,185,307
Lease liability	(135,934)	(263,750)
Net cash used in operating activities	(19,273,989)	(17,179,938)
Cash flows from investing activities:
Purchases of property and equipment		(10,144)
Net cash used in investing activities		(10,144)
Cash flows from financing activities:
Proceeds from the exercise of stock options		150,949
Net cash provided by financing activities		150,949
Decrease in cash and cash equivalents	(19,273,989)	(17,039,133)
Effect of exchange rate changes on cash	60,148	(188,232)
Cash and cash equivalents-beginning of year	89,017,686	130,088,869
Cash and cash equivalents-end of period	$ 69,803,845	$ 112,861,504

Nature of business and basis of

Nature of business and basis of presentation	6 Months Ended
	Jun. 30, 2021
Nature of business and basis of presentation
Nature of business and basis of presentation	1. Nature of business and basis of presentation Nature of business TP53 Corporate reorganization Each share of common stock of Aprea Therapeutics AB ($0.11 par value) was also exchanged on a one for one basis into shares of common stock of the Company ($0.001 par value). Basis of presentation and management plans Since its inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, and raising capital, and has financed its operations through the issuance of convertible preferred stock and common stock. The Company is subject to risks common to companies in the biopharmaceutical industry. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be maintained, that any therapeutic products developed will obtain required regulatory approval or that any approved or consumer products will be commercially viable. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will generate significant product sales. The Company believes that the June 30, 2021 cash balance of approximately $69.8 million will be sufficient to fund the Company’s operations into 2023. In the event that additional funds are not available thereafter, management would expect to significantly reduce expenditures to conserve cash, which would involve scaling back or curtailing new development activity.

Summary of significant accounti

Summary of significant accounting policies	6 Months Ended
	Jun. 30, 2021
Summary of significant accounting policies
Summary of significant accounting policies	2. Summary of significant accounting policies The Company's complete listing of significant accounting policies are described in Note 2 to the Company's audited consolidated financial statements as of December 31, 2020 included in its annual report on Form 10-K filed with the Securities and Exchange Commission (or the “SEC”). Principles of consolidation Unaudited interim consolidated financial statements footnote disclosure normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. These unaudited condensed interim financial statements should be read in conjunction with the audited financial statements and related notes included in the Company’s annual report on Form 10-K for the year ended December 31, 2020 filed with the SEC. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements, and in management’s opinion, include all adjustments, consisting of only normal recurring adjustments, necessary for the fair presentation of the financial information for the interim periods have been made. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results to be expected for the full fiscal year or any future period. Use of estimates Foreign currency and currency translation Cash and cash equivalents— Fair value of financial instruments ● Level 1 inputs: Quoted prices in active markets for identical assets or liabilities. ● Level 2 inputs: Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. ● Level 3 inputs: Unobservable inputs developed using estimates or assumptions developed by the Company, which reflect those that a market participant would use in pricing the asset or liability. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in 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 Company’s financial instruments consist of cash and cash equivalents and accounts payable. The carrying amount of accounts payable is considered a reasonable estimate of fair value due to the short-term maturity. Accounting for leases package At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on specific facts and circumstances, the existence of an identified asset(s), if any, and the Company’s control over the use of the identified asset(s), if applicable. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of future lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. The Company’s incremental borrowing rate ranged from approximately 3.0% to 4.3% based on the remaining lease term of the applicable leases. The Company has elected not to separate lease and non-lease components as a single component. Operating leases are recognized on the balance sheet as ROU lease assets, lease liabilities current and lease liabilities non-current. Fixed rents are included in the calculation of the lease balances while variable costs paid for certain operating and pass-through costs are excluded. Lease expense is recognized over the expected term on a straight-line basis. Stock-based compensation For stock-based awards granted to non-employees, compensation expense is recognized over the period during which services are rendered by such non-employees until completed in accordance with the FASB issued ASU No. 2018-07, Compensation Stock Compensation (Topic 718): Improvements to Nonemployee Share Based Payment Accounting. The new standard largely aligns the accounting for share based payment awards issued to employees and nonemployees by expanding the scope of ASC 718 to apply to nonemployee share based transactions, as long as the transaction is not effectively a form of financing. The Company estimates the fair value of each stock option grant on the date of grant using the Black Scholes option pricing model, which uses as inputs the fair value of the Company’s common stock and assumptions the Company makes for the volatility of its common stock, the expected term of its stock options, the risk-free interest rate for a period that approximates the expected term of its stock options and its expected dividend yield. The Company also awards restricted stock units (“RSUs”) to employees and directors. RSUs are generally subject to forfeiture if employment terminates prior to the completion of the vesting restrictions. The Company expenses the cost of the RSUs, which is determined to be the fair market value of the shares of common stock underlying the RSUs at the date of grant, ratably over the period during which the vesting restrictions lapse. Net loss per share Company computes diluted net loss per common share after giving consideration to all potentially dilutive common shares, including options to purchase common stock, outstanding during the period determined using the treasury-stock and if-converted methods, except where the effect of including such securities would be antidilutive. Because the Company has reported net losses since inception, these potential common shares have been anti-dilutive and basic and diluted loss per share have been the same. The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti-dilutive (in common stock equivalent shares): ​ ​ ​ ​ ​ ​ ​ Six months ended June 30, ​ 2021 2020 Options to purchase common stock 4,821,759 3,755,959 Unvested restricted stock units ​ 507,050 ​ — Total shares of common stock equivalents 5,328,809 3,755,959 ​ Recently issued accounting pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that the Company adopts as of the specified effective date. Management does not believe that any recently issued, but not yet effective accounting pronouncements, if adopted, would have a material impact on the accompanying financial statements.

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases
Leases	3. Leases The Company is party to two operating leases for office and laboratory space. The Company’s finance leases are immaterial both individually and in the aggregate. The Company has elected to apply the short-term lease exception to all leases of one year or less. Rent expense for three and six months ended June 30, 2021 was $84,401 and $176,087, respectively. Rent expense for the three and six months ended June 30, 2020 was $77,500 and $157,325, respectively. The Company has an operating lease in Boston, Massachusetts for office space which was amended effective July 1, 2021. The lease will now expire in December 2022 and does not have any renewal options. The Company also has an operating lease for office and laboratory space in Solna, Sweden that expires in June 2022. Quantitative information regarding the Company’s leases for the three and six months ended June 30, 2021 and 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended June 30, ​ Six months ended June 30, Lease Cost 2021 2020 ​ 2021 2020 Operating lease cost ​ $ 58,481 ​ $ 27,265 ​ $ 116,404 ​ $ 54,223 Other Information ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows paid for amounts included in the measurement of lease liabilities ​ $ 63,482 ​ $ 62,909 ​ $ 126,966 ​ $ 125,818 Operating lease liabilities arising from obtaining right‑of‑use assets ​ $ — ​ $ — ​ $ — ​ $ — Weighted average remaining lease term (years) ​ ​ 0.5 - 1.0 ​ ​ 1.5 - 2.0 ​ 0.5 - 1.0 ​ 1.5 - 2.0 Weighted average discount rate ​ ​ 3.0 - 4.3% ​ ​ 3.0 - 4.3% ​ ​ 3.0 - 4.3% ​ 3.0 - 4.3% ​ ​ Future lease payments under noncancelable leases are as follows at June 30, 2021: ​ ​ ​ ​ ​ Operating Future Lease Payments ​ Leases 2021 ​ $ 132,675 2022 ​ 69,563 Total Lease Payments ​ $ 202,238 Less: Imputed Interest ​ (3,019) Total Lease Liabilities ​ $ 199,219 ​ As most of the Company’s leases do not provide an implicit rate, the Company used its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The Company uses the incremental borrowing rate on January 1, 2019 for operating leases that commenced prior to that date.

Accrued expenses

Accrued expenses	6 Months Ended
	Jun. 30, 2021
Accrued expenses
Accrued expenses	4. Accrued expenses Accrued expenses consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 Professional fees ​ $ 480,828 ​ $ 224,424 Compensation and benefits ​ 872,665 ​ 1,515,312 Research and development ​ 6,532,487 ​ 8,158,302 Other ​ 151,544 ​ 673,199 Total accrued expenses ​ $ 8,037,524 ​ $ 10,571,237 ​

Stockholders' equity

Stockholders' equity	6 Months Ended
	Jun. 30, 2021
Stockholders' equity
Stockholders' equity	5. Stockholders’ equity The total number of shares of all classes of capital stock that the Company is authorized to issue is 440,000,000 shares, consisting of 400,000,000 shares of common stock, par value $0.001 per share and 40,000,000 shares of preferred stock, par value $0.001 per share. Common Stock The holders of common stock are entitled to one vote for each share of common stock. In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company, after the payment or provision for payment of all debts and liabilities of the Company, the holders of common stock shall be entitled to share in the remaining assets of the Company available for distribution, if any. Shelf Registration Statement On November 12, 2020, the Company filed a universal shelf registration statement with the SEC for the issuance of common stock, preferred stock, warrants, rights, debt securities and units up to an aggregate of $350.0 million. On November 30, 2020, the Shelf Registration Statement was declared effective by the SEC. The universal shelf registration statement includes an at-the-market (“ATM”) offering program for the sale of up to $50.0 million of shares of the Company’s common stock. As of June 30, 2021, no sales of any equity or debt securities occurred under the ATM. Stock-Based Compensation Expense The Company recorded stock-based compensation expense of $1,863,498, and $3,686,060 for the three and six months ended June 30, 2021, respectively. The Company recorded stock-based compensation expense of for the three and six months ended June 30, 2020, respectively. . ​

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Taxes
Income Taxes	6. Income Taxes ​ The Company has no income tax expense due to operating losses incurred for the three and six months ended June 30, 2021 and 2020. The Company has provided a valuation allowance for the full amount of the net deferred tax assets as, based on all available evidence, it is considered more likely than not that all the recorded deferred tax assets will not be realized in a future period. Realization of the future tax benefits is dependent on may factors, including the Company’s ability to generate taxable income within the net operating loss carryforward period. Under the provisions of the U.S. Internal Revenue Code and Sweden tax law, certain substantial changes in the Company’s ownership, including a sale of the Company or significant changes in ownership due to sales of equity, may have limited, or may limit in the future, the amount of net operating loss carryforwards that could be used annually to offset future taxable income. For U.S. and Swedish income tax purposes, the Company has not completed a study to assess whether a change of control has occurred or whether there have been changes of control since the Company’s formation due to the complexity and cost associated with such study and because there could be additional changes of control in the future. As a result, the Company is not able to estimate the effect of the change in control, if any, on the Company’s ability to utilize U.S. or Swedish net operating losses or other tax attribute carryforwards in the future. For Swedish income tax purposes, the Company’s net operating losses may be subject to limitations in accordance with the country’s group contribution restriction laws. ​ The Company files tax returns in Sweden, the United States and Massachusetts, and all tax years since inception remain open to examination by the major taxing jurisdictions to which the Company is subject, as carryforward attributes generated in years past may still be adjusted upon examination by the Internal Revenue Service (IRS) or other authorities if they have or will be used in a future period. The Company is not currently under examination by the IRS or any other jurisdictions for any tax years. As tax law is complex and often subject to varied interpretations, it is uncertain whether some of the Company’s tax positions will be sustained upon examination. Tax liabilities associated with uncertain tax positions represent unrecognized tax benefits, which arise when the estimated benefit recorded in the Company’s financial statements differs from the amounts taken or expected to be taken in a tax return because of the uncertainties described above. If recognized, the Company’s uncertain tax positions would all be absorbed by net operating losses. As of June 30, 2021 and December 31, 2020, the Company had approximately $0.8 million of liabilities related to uncertain tax positions. As the Company’s uncertain tax positions can be offset by available net operating losses, the Company did not recognize interest and penalties for 2021 and 2020.

Commitments and contingencies

Commitments and contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and contingencies
Commitments and contingencies	7. Commitments and contingencies The Company records a provision for contingent losses when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. As of June 30, 2021, the Company has not recorded a provision for any contingent losses.

Summary of significant accoun_2

Summary of significant accounting policies (Policies)	6 Months Ended
	Jun. 30, 2021
Summary of significant accounting policies
Principles of consolidation	Principles of consolidation
Unaudited interim condensed consolidated financial statements	Unaudited interim consolidated financial statements footnote disclosure normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. These unaudited condensed interim financial statements should be read in conjunction with the audited financial statements and related notes included in the Company’s annual report on Form 10-K for the year ended December 31, 2020 filed with the SEC. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements, and in management’s opinion, include all adjustments, consisting of only normal recurring adjustments, necessary for the fair presentation of the financial information for the interim periods have been made. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results to be expected for the full fiscal year or any future period.
Use of estimates	Use of estimates
Foreign currency and currency translation	Foreign currency and currency translation
Cash and cash equivalents	Cash and cash equivalents—
Fair value of financial instruments	Fair value of financial instruments ● Level 1 inputs: Quoted prices in active markets for identical assets or liabilities. ● Level 2 inputs: Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. ● Level 3 inputs: Unobservable inputs developed using estimates or assumptions developed by the Company, which reflect those that a market participant would use in pricing the asset or liability. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in 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 Company’s financial instruments consist of cash and cash equivalents and accounts payable. The carrying amount of accounts payable is considered a reasonable estimate of fair value due to the short-term maturity.
Accounting for leases	Accounting for leases package At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on specific facts and circumstances, the existence of an identified asset(s), if any, and the Company’s control over the use of the identified asset(s), if applicable. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of future lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. The Company’s incremental borrowing rate ranged from approximately 3.0% to 4.3% based on the remaining lease term of the applicable leases. The Company has elected not to separate lease and non-lease components as a single component. Operating leases are recognized on the balance sheet as ROU lease assets, lease liabilities current and lease liabilities non-current. Fixed rents are included in the calculation of the lease balances while variable costs paid for certain operating and pass-through costs are excluded. Lease expense is recognized over the expected term on a straight-line basis.
Stock based compensation	Stock-based compensation For stock-based awards granted to non-employees, compensation expense is recognized over the period during which services are rendered by such non-employees until completed in accordance with the FASB issued ASU No. 2018-07, Compensation Stock Compensation (Topic 718): Improvements to Nonemployee Share Based Payment Accounting. The new standard largely aligns the accounting for share based payment awards issued to employees and nonemployees by expanding the scope of ASC 718 to apply to nonemployee share based transactions, as long as the transaction is not effectively a form of financing. The Company estimates the fair value of each stock option grant on the date of grant using the Black Scholes option pricing model, which uses as inputs the fair value of the Company’s common stock and assumptions the Company makes for the volatility of its common stock, the expected term of its stock options, the risk-free interest rate for a period that approximates the expected term of its stock options and its expected dividend yield. The Company also awards restricted stock units (“RSUs”) to employees and directors. RSUs are generally subject to forfeiture if employment terminates prior to the completion of the vesting restrictions. The Company expenses the cost of the RSUs, which is determined to be the fair market value of the shares of common stock underlying the RSUs at the date of grant, ratably over the period during which the vesting restrictions lapse.
Net loss per share	Net loss per share Company computes diluted net loss per common share after giving consideration to all potentially dilutive common shares, including options to purchase common stock, outstanding during the period determined using the treasury-stock and if-converted methods, except where the effect of including such securities would be antidilutive. Because the Company has reported net losses since inception, these potential common shares have been anti-dilutive and basic and diluted loss per share have been the same. The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti-dilutive (in common stock equivalent shares): ​ ​ ​ ​ ​ ​ ​ Six months ended June 30, ​ 2021 2020 Options to purchase common stock 4,821,759 3,755,959 Unvested restricted stock units ​ 507,050 ​ — Total shares of common stock equivalents 5,328,809 3,755,959
Recently issued accounting pronouncements	Recently issued accounting pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that the Company adopts as of the specified effective date. Management does not believe that any recently issued, but not yet effective accounting pronouncements, if adopted, would have a material impact on the accompanying financial statements.

Summary of significant accoun_3

Summary of significant accounting policies (Tables)	6 Months Ended
	Jun. 30, 2021
Summary of significant accounting policies
Schedule of potentially dilutive securities excluded from calculation of diluted net loss per share	The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti-dilutive (in common stock equivalent shares): ​ ​ ​ ​ ​ ​ ​ Six months ended June 30, ​ 2021 2020 Options to purchase common stock 4,821,759 3,755,959 Unvested restricted stock units ​ 507,050 ​ — Total shares of common stock equivalents 5,328,809 3,755,959

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases
Summary of quantitative information regarding the Company's leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended June 30, ​ Six months ended June 30, Lease Cost 2021 2020 ​ 2021 2020 Operating lease cost ​ $ 58,481 ​ $ 27,265 ​ $ 116,404 ​ $ 54,223 Other Information ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows paid for amounts included in the measurement of lease liabilities ​ $ 63,482 ​ $ 62,909 ​ $ 126,966 ​ $ 125,818 Operating lease liabilities arising from obtaining right‑of‑use assets ​ $ — ​ $ — ​ $ — ​ $ — Weighted average remaining lease term (years) ​ ​ 0.5 - 1.0 ​ ​ 1.5 - 2.0 ​ 0.5 - 1.0 ​ 1.5 - 2.0 Weighted average discount rate ​ ​ 3.0 - 4.3% ​ ​ 3.0 - 4.3% ​ ​ 3.0 - 4.3% ​ 3.0 - 4.3%
Schedule of future lease payments under noncancellable leases	Future lease payments under noncancelable leases are as follows at June 30, 2021: ​ ​ ​ ​ ​ Operating Future Lease Payments ​ Leases 2021 ​ $ 132,675 2022 ​ 69,563 Total Lease Payments ​ $ 202,238 Less: Imputed Interest ​ (3,019) Total Lease Liabilities ​ $ 199,219

Accrued expenses (Tables)

Accrued expenses (Tables)	6 Months Ended
	Jun. 30, 2021
Accrued expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 Professional fees ​ $ 480,828 ​ $ 224,424 Compensation and benefits ​ 872,665 ​ 1,515,312 Research and development ​ 6,532,487 ​ 8,158,302 Other ​ 151,544 ​ 673,199 Total accrued expenses ​ $ 8,037,524 ​ $ 10,571,237

Nature of business and basis _2

Nature of business and basis of presentation (Details)	1 Months Ended
	Sep. 30, 2019$ / shares	Jun. 30, 2021USD ($)$ / shares	Dec. 31, 2020USD ($)$ / shares
Cash balance | $		$ 69,803,845	$ 89,017,686
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Aprea Therapeutics AB
Common stock, par value (in dollars per share)	$ 0.11
Convertible preferred stock | Aprea Therapeutics AB
Conversion ratio	1
Common Stock | Aprea Therapeutics AB
Conversion ratio	1

Summary of significant accoun_4

Summary of significant accounting policies - Leases (Details)	6 Months Ended
	Jun. 30, 2021
Leases
Leases, election of practical expedients package	true
Minimum
Leases
Incremental borrowing rate (as a percent)	3.00%
Maximum
Leases
Incremental borrowing rate (as a percent)	4.30%

Summary of significant accoun_5

Summary of significant accounting policies - Potentially dilutive securities (Details) - shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Potentially dilutive securities
Total shares of common stock equivalents	5,328,809	3,755,959
Options to purchase common stock
Potentially dilutive securities
Total shares of common stock equivalents	4,821,759	3,755,959
Restricted stock units
Potentially dilutive securities
Total shares of common stock equivalents	507,050

Leases - Summary (Details)

Leases - Summary (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)lease	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)lease	Jun. 30, 2020USD ($)
Leases
Number of operating leases | lease	2		2
Rent expense | $	$ 84,401	$ 77,500	$ 176,087	$ 157,325

Leases - Quantitative Informati

Leases - Quantitative Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Quantitative information regarding the Company's leases
Operating lease cost	$ 58,481	$ 27,265	$ 116,404	$ 54,223
Other Information
Operating cash flows paid for amounts included in the measurement of lease liabilities	$ 63,482	$ 62,909	$ 126,966	$ 125,818
Minimum
Other Information
Weighted average remaining lease term (years)	6 months	1 year 6 months	6 months	1 year 6 months
Weighted average discount rate	3.00%	3.00%	3.00%	3.00%
Maximum
Other Information
Weighted average remaining lease term (years)	1 year	2 years	1 year	2 years
Weighted average discount rate	4.30%	4.30%	4.30%	4.30%

Leases - Future lease payments

Leases - Future lease payments (Details)	Jun. 30, 2021USD ($)
Future Lease Payments
2021	$ 132,675
2022	69,563
Total Lease Payments	202,238
Less: Imputed Interest	(3,019)
Total Lease Liabilities	$ 199,219

Accrued expenses (Details)

Accrued expenses (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Accrued expenses
Professional fees	$ 480,828	$ 224,424
Compensation and benefits	872,665	1,515,312
Research and development	6,532,487	8,158,302
Other	151,544	673,199
Total accrued expenses	$ 8,037,524	$ 10,571,237

Stockholders' equity (deficit)

Stockholders' equity (deficit) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)Vote$ / sharesshares	Jun. 30, 2020USD ($)	Dec. 31, 2020$ / sharesshares	Nov. 12, 2020USD ($)	Sep. 30, 2019$ / shares
Stockholders' equity
Aggregate number of authorized shares for all classes of equity | shares	440,000,000		440,000,000
Common stock, shares authorized | shares	400,000,000		400,000,000		400,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.001		$ 0.001		$ 0.001		$ 0.001
Preferred stock, shares authorized | shares	40,000,000		40,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.001		$ 0.001
Number of voting rights per common share | Vote			1
Maximum amount to be issued under universal shelf registration statement						$ 350,000,000
Maximum amount to be issued under at-the-market offering program						$ 50,000,000
Amount of equity or debt securities sold under at-the-market offering program	$ 0		$ 0
Stock based compensation expense	$ 1,863,498	$ 1,256,460	$ 3,686,060	$ 2,161,931

Income taxes - Narrative (Detai

Income taxes - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Income Taxes
Income tax expense	$ 0	$ 0	$ 0	$ 0
Uncertain tax positions	$ 800,000		$ 800,000		$ 800,000

Commitments and contingencies (

Commitments and contingencies (Details)	6 Months Ended
	Jun. 30, 2021USD ($)
Commitments and contingencies
Provision for contingent losses	$ 0