View Filing Data

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2020	Aug. 13, 2020
Entity Registrant Name	HOOKIPA Pharma Inc.
Entity Central Index Key	0001760542
Document Type	10-Q
Document Period End Date	Jun. 30, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Interactive Data Current	Yes
Entity Ex Transition Period	true
Entity Shell Company	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Common stock
Entity Common Stock, Shares Outstanding		21,834,692
Class A common stock
Entity Common Stock, Shares Outstanding		3,819,732

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 92,857	$ 113,151
Accounts receivable	4,738	1,537
Receivable research incentives	10,950	8,190
Prepaid expenses and other current assets	9,348	5,139
Total current assets	117,893	128,017
Non-current assets:
Restricted cash	425	424
Property and equipment, net	6,030	5,126
Operating lease right of use assets	6,949	7,875
Finance lease right of use assets	1,399	1,602
Other non-current assets	572	701
Total non-current assets	15,375	15,728
Total assets	133,268	143,745
Current liabilities
Accounts payable	6,965	944
Deferred revenues	4,365	3,591
Operating lease liabilities, current	1,841	1,814
Accrued expenses and other current liabilities	5,400	8,406
Total current liabilities	18,571	14,755
Non-current liabilities
Loans payable, non-current	3,818	3,495
Operating lease liabilities, non-current	4,398	5,290
Deferred revenues, non-current	760	72
Other non-current liabilities	1,806	2,234
Total non-current liabilities	10,782	11,091
Total liabilities	29,353	25,846
Stockholders' equity:
Additional paid-in capital	229,828	225,568
Accumulated other comprehensive loss	(4,879)	(4,653)
Accumulated deficit	(121,037)	(103,019)
Total stockholders' equity	103,915	117,899
Total liabilities, convertible preferred stock and stockholders' equity	133,268	143,745
Common stock
Stockholders' equity:
Common stock	3	3
Class A common stock
Stockholders' equity:
Common stock	$ 0	$ 0

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	21,834,692	21,746,392
Common stock, shares outstanding	21,834,692	21,746,392
Class A common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	3,900,000	3,900,000
Common stock, shares issued	3,819,732	3,819,732
Common stock, shares outstanding	3,819,732	3,819,732

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Revenue from collaboration and licensing	$ 6,685	$ 4,051	$ 10,381	$ 6,286
Operating expenses:
Research and development	(11,564)	(13,929)	(23,090)	(24,108)
General and administrative	(4,347)	(3,751)	(8,976)	(6,462)
Total operating expenses	(15,911)	(17,680)	(32,066)	(30,570)
Loss from operations	(9,226)	(13,629)	(21,685)	(24,284)
Other income (expense):
Grant income	1,595	1,544	3,067	2,736
Interest income	59	511	371	575
Interest expense	(166)	(210)	(393)	(423)
Other income and expenses, net	646	(195)	622	88
Total other income, net	2,134	1,650	3,667	2,976
Net loss before tax	(7,092)	(11,979)	(18,018)	(21,308)
Income tax expense	0	(100)	0	(100)
Net loss	(7,092)	(12,079)	(18,018)	(21,408)
Other comprehensive loss:
Foreign currency translation gain (loss), net of tax	(133)	300	(226)	(435)
Comprehensive loss	$ (7,225)	$ (11,779)	$ (18,244)	$ (21,843)
Net loss per share - basic and diluted	$ (0.28)	$ (0.63)	$ (0.70)	$ (2.10)
Weighted average common shares outstanding — basic and diluted	25,647,819	19,240,977	25,638,913	10,174,157

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock Common stock	Common Stock Class A common stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Convertible preferred stock	Total
Balance at the beginning of the period at Dec. 31, 2018						$ 104,774
Balance at the beginning of the period (in shares) at Dec. 31, 2018						1,323,506
Increase (Decrease) in Temporary Equity
Issuance of Series D preferred stock, net of issuance costs of $158						$ 37,274
Issuance of Series D preferred stock, net of issuance costs of $158 (in shares)						257,000
Balance at the end of the period at Mar. 31, 2019						$ 142,048
Balance at the end of the period (in shares) at Mar. 31, 2019						1,580,506
Balance at the beginning of the period at Dec. 31, 2018	$ 0		$ 3,327	$ (3,720)	$ (59,982)		$ (60,375)
Balance at the beginning of the period (in shares) at Dec. 31, 2018	1,006,595
Increase (Decrease) in Stockholders' Equity
Foreign currency translation adjustment, net of tax				(736)			(736)
Stock-based compensation expense			383				383
Net loss					(9,329)		(9,329)
Balance at the end of the period at Mar. 31, 2019	$ 0		3,710	(4,456)	(69,311)		(70,057)
Balance at the end of the period (in shares) at Mar. 31, 2019	1,006,595
Balance at the beginning of the period at Dec. 31, 2018						$ 104,774
Balance at the beginning of the period (in shares) at Dec. 31, 2018						1,323,506
Balance at the beginning of the period at Dec. 31, 2018	$ 0		3,327	(3,720)	(59,982)		(60,375)
Balance at the beginning of the period (in shares) at Dec. 31, 2018	1,006,595
Increase (Decrease) in Stockholders' Equity
Foreign currency translation adjustment, net of tax							(435)
Net loss							(21,408)
Balance at the end of the period at Jun. 30, 2019	$ 3	$ 0	221,576	(4,156)	(81,390)		136,033
Balance at the end of the period (in shares) at Jun. 30, 2019	21,588,756	3,819,732
Balance at the beginning of the period at Dec. 31, 2018						$ 104,774
Balance at the beginning of the period (in shares) at Dec. 31, 2018						1,323,506
Balance at the beginning of the period at Dec. 31, 2018	$ 0		3,327	(3,720)	(59,982)		(60,375)
Balance at the beginning of the period (in shares) at Dec. 31, 2018	1,006,595
Increase (Decrease) in Stockholders' Equity
Net loss							(43,000)
Balance at the end of the period at Dec. 31, 2019	$ 3	$ 0	225,568	(4,653)	(103,019)		117,899
Balance at the end of the period (in shares) at Dec. 31, 2019	21,746,392	3,819,732
Balance at the beginning of the period at Mar. 31, 2019						$ 142,048
Balance at the beginning of the period (in shares) at Mar. 31, 2019						1,580,506
Increase (Decrease) in Temporary Equity
Conversion of Series A, B, C and D preferred stock into common stock upon initial public offering						$ (142,048)
Conversion of Series A, B, C and D preferred stock into common stock upon initial public offering (in shares)						(1,580,506)
Balance at the beginning of the period at Mar. 31, 2019	$ 0		3,710	(4,456)	(69,311)		(70,057)
Balance at the beginning of the period (in shares) at Mar. 31, 2019	1,006,595
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon initial public offering at $14.00 per share for cash, net of issuance costs of $9,386	$ 1		74,614				74,615
Issuance of common stock upon initial public offering at $14.00 per share for cash, net of issuance costs of $9,386(in shares)	6,000,000
Conversion of Series A, B, C and D preferred stock into common stock upon initial public offering	$ 2	$ 0	142,046				142,048
Conversion of Series A, B, C and D preferred stock into common stock upon initial public offering(in shares)	14,582,161	3,819,732
Foreign currency translation adjustment, net of tax				300			300
Stock-based compensation expense			1,206				1,206
Net loss					(12,079)		(12,079)
Balance at the end of the period at Jun. 30, 2019	$ 3	$ 0	221,576	(4,156)	(81,390)		136,033
Balance at the end of the period (in shares) at Jun. 30, 2019	21,588,756	3,819,732
Balance at the beginning of the period at Dec. 31, 2019	$ 3	$ 0	225,568	(4,653)	(103,019)		117,899
Balance at the beginning of the period (in shares) at Dec. 31, 2019	21,746,392	3,819,732
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options	$ 0		8				8
Issuance of common stock upon exercise of stock options (in shares)	78,598
Foreign currency translation adjustment, net of tax				(93)			(93)
Stock-based compensation expense			2,094				2,094
Net loss					(10,926)		(10,926)
Balance at the end of the period at Mar. 31, 2020	$ 3	$ 0	227,670	(4,746)	(113,945)		108,982
Balance at the end of the period (in shares) at Mar. 31, 2020	21,824,990	3,819,732
Balance at the beginning of the period at Dec. 31, 2019	$ 3	$ 0	225,568	(4,653)	(103,019)		$ 117,899
Balance at the beginning of the period (in shares) at Dec. 31, 2019	21,746,392	3,819,732
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options (in shares)							88,300
Foreign currency translation adjustment, net of tax							$ (226)
Net loss							(18,018)
Balance at the end of the period at Jun. 30, 2020	$ 3	$ 0	229,828	(4,879)	(121,037)		103,915
Balance at the end of the period (in shares) at Jun. 30, 2020	21,834,692	3,819,732
Balance at the beginning of the period at Mar. 31, 2020	$ 3	$ 0	227,670	(4,746)	(113,945)		108,982
Balance at the beginning of the period (in shares) at Mar. 31, 2020	21,824,990	3,819,732
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options	$ 0		7				7
Issuance of common stock upon exercise of stock options (in shares)	9,702
Foreign currency translation adjustment, net of tax				(133)			(133)
Stock-based compensation expense			2,151				2,151
Net loss					(7,092)		(7,092)
Balance at the end of the period at Jun. 30, 2020	$ 3	$ 0	$ 229,828	$ (4,879)	$ (121,037)		$ 103,915
Balance at the end of the period (in shares) at Jun. 30, 2020	21,834,692	3,819,732

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Series D convertible preferred stock
Issuance costs	$ 158

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities:
Net loss	$ (18,018)	$ (21,408)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	4,245	1,589
Depreciation expense	887	670
Non-cash operating lease expense	987	735
Other non-cash items	(29)	51
Changes in operating assets and liabilities:
Accounts receivable	(2,971)	1,892
Prepaid expenses and other current assets	(6,531)	(5,575)
Other non-current assets	127	204
Accounts payable	4,833	994
Deferred revenues	1,431	(2,265)
Operating lease liabilities	(927)	(1,698)
Accrued expenses and other liabilities	(1,668)	1,438
Other non-current liabilities	(39)	(80)
Net cash used in operating activities	(17,673)	(23,453)
Investing activities:
Purchases of property and equipment	(1,241)	(591)
Net cash used in investing activities	(1,241)	(591)
Financing activities:
Payments related to finance leases	(65)	(1,406)
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs		37,274
Proceeds from issuance of common stock, net of issuance costs	15	75,298
Payments for deferred offering costs	(128)
Repayments of borrowings	(1,256)	0
Net cash provided by (used in) financing activities	(1,434)	111,166
Net increase (decrease) in cash, cash equivalents and restricted cash	(20,348)	87,122
Cash, cash equivalents and restricted cash at beginning of period	113,575	48,580
Effect of exchange rate changes on cash, cash equivalents and restricted cash	55	(489)
Cash, cash equivalents and restricted cash at end of period	93,282	135,213
Supplemental disclosure of cash flow information:
Cash paid for interest	(47)	(32)
Cash paid for income taxes	0	(100)
Supplemental disclosure of non-cash investing activities:
Property and equipment additions in accounts payable and accrued expenses	$ (368)	$ (191)

Nature of the business and organization	6 Months Ended
Nature of the business and organization	Jun. 30, 2020
Nature of the business and organization
Nature of the business and organization	1. Nature of the business and organization HOOKIPA Pharma Inc. (“HOOKIPA” or the “Company”) is a clinical-stage biopharmaceutical company developing a new class of immunotherapeutics targeting infectious diseases and cancers based on its proprietary arenavirus platform that is designed to reprogram the body’s immune system. The Company was incorporated under the name of Hookipa Biotech, Inc. under the laws of the State of Delaware in February 2017 as a fully-owned subsidiary of Hookipa Biotech AG. In June 2018, the Company changed its name from Hookipa Biotech, Inc. to HOOKIPA Pharma Inc. and in order to effectuate the change of the jurisdiction of incorporation, the Company acquired all of the shares of Hookipa Biotech AG, now Hookipa Biotech GmbH. HOOKIPA is headquartered in New York, with European research and preclinical development operations headquartered in Vienna, Austria. In April 2019, the Company closed its initial public offering (“IPO”) and its common stock started trading on the Nasdaq Global Select Market under the ticker symbol “HOOK”. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, the ability to establish clinical- and commercial-scale manufacturing processes and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities and may not ultimately lead to a marketing approval and commercialization of a product. Even if the Company’s drug development efforts are successful, it is uncertain if and when the Company will realize significant revenue from product sales.

Summary of significant accounting policies

6 Months Ended

Jun. 30, 2020

Summary of significant accounting policies

Summary of significant accounting policies

2. Summary of significant accounting policies

Basis of presentation

The Company’s condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation.

The accompanying condensed consolidated balance sheet as of June 30, 2020, the condensed consolidated statements of operations, and comprehensive loss for the three and six months ended June 30, 2020 and 2019, the condensed consolidated statement of redeemable convertible preferred stock and stockholders’ deficit for the three and six months ended June 30, 2020 and 2019 and the condensed consolidated statements of cash flows for the six months ended June 30, 2020 and 2019 are unaudited.

The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement for interim reporting. Certain information and footnote disclosures typically included in annual financial statements prepared in accordance with GAAP have been condensed or omitted. Accordingly, these unaudited interim condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission. The results for any interim period are not necessarily indicative of results for any future period. Certain previous year amounts have been reclassified to conform to the current year presentation.

Going concern

Since inception, the Company’s activities have consisted primarily of performing research and development to advance its technologies. The Company is still in the development phase and has not been marketing its technologies to date. Through June 30, 2020, the Company has funded its operations with proceeds from sales of common stock in its IPO, sales of redeemable convertible preferred stock, collaboration and licensing agreements, grants and borrowings under various agreements with foreign public funding agencies. Since inception, the Company has incurred recurring losses, including net losses of $18.0 million for the six months ended June 30, 2020 and $43.0 million for the year ended December 31, 2019. As of June 30, 2020, the Company had an accumulated deficit of $121.0 million. The Company expects to continue to generate operating losses in the foreseeable future. As of August 13, 2020, the filing date of this Quarterly Report on Form 10‑Q, the Company expects that its cash and cash equivalents will be sufficient to fund its operating expenses, capital expenditure requirements and debt service payments through at least 12 months from the issuance date of the condensed consolidated financial statements.

The Company will seek additional funding in order to reach its development and commercialization objectives. The Company will seek funds through further equity financings, debt financings, collaborations, strategic alliances and marketing, distribution or licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects.

The accompanying condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. The condensed consolidated financial statements do not reflect any adjustments relating to the recoverability and classification of assets or the amounts and classification of liabilities that might be necessary if the Company is unable to continue as a going concern.

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 contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue, income and expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the recognition of revenue and income, the accrual of research and development expenses, the present value of lease right of use assets and corresponding liabilities, the valuation of common and preferred stock, the valuation of stock-based awards and the valuation of liabilities. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain it or treat COVID-19, as well as the economic impact on local, regional, national and international customers and markets. The Company’s accounting estimates and assumptions may change over time in response to COVID-19 and the change could be material in future periods. As of the date of issuance of these unaudited condensed consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update estimates, judgments or revise the carrying value of any assets or liabilities. Actual results may differ from those estimates or assumptions.

Deferred offering costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded in stockholders’ equity as a reduction of the additional paid-in capital on a pro-rata basis generated as a result of the offering. Should the in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations and comprehensive loss.

Concentrations of credit risk and of significant suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and short-term bank deposits held with banks in excess of publicly insured limits. The net proceeds from the Company’s offerings have been deposited in interest-bearing bank accounts with investment grade US financial institutions and have been partially invested in a money market fund as of June 30, 2020. The money market fund, held in U.S. dollar, is primarily invested in U.S. and foreign short-term debt obligations. As of December 31, 2019 and June 30, 2020, the Company’s cash and cash equivalents included smaller amounts of cash balances held in accounts with European banks at the Company’s Austrian subsidiary, partially in euros. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

The Company relies, and expects to continue to rely, on a small number of vendors to manufacture supplies and raw materials for its development programs. These programs could be adversely affected by a significant interruption in these manufacturing services or the availability of raw materials.

Cash equivalents

The Company considers all highly liquid investments with maturities of three months or less at the date of purchase to be cash equivalents. As of December 31, 2019 and June 30, 2020, cash equivalents consisted of money market funds.

Fair value measurements

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

Level 1 - Quoted prices in active markets for identical assets or liabilities.

Level 2 - Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The Company’s cash equivalents are carried at fair value, determined according to the fair value hierarchy described above (see Note 4).

Property and equipment

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful life of each asset as follows:


		Estimated useful life
Leasehold improvements		5 years
Laboratory equipment		3 - 10 years
Furniture and fixtures		3 - 10 years
Computer equipment and software		3 - 4 years

Costs for capital assets not yet placed into service are capitalized as construction-in-progress and depreciated once placed into service. Expenditures for repairs and maintenance are charged to expense as incurred.

Leases

The determination whether an arrangement qualifies as a lease is made at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the option will be exercised. The Company uses the implicit rate when readily determinable and uses its incremental borrowing rate when the implicit rate is not readily determinable based upon the information available at the commencement date in determining the present value of the lease payments. The incremental borrowing rate is determined using a secured borrowing rate for the same currency and term as the associated lease. The lease payments used to determine operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation when determinable and are recognized as operating lease assets on the consolidated balance sheets. In addition, certain of the Company’s arrangements contain lease and non-lease components. The Company generally separate lease payments from non-lease payments. Operating leases are reflected in operating lease assets, in accrued expenses and other current liabilities and in non-current operating lease liabilities in the consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. The right-of-use asset is tested for impairment in accordance with ASC 360.

Revenue recognition from contracts with customers

The Company entered into a collaboration and license agreement (the “Gilead Agreement”) with Gilead Sciences, Inc. (“Gilead”) whereby the parties agreed to collaborate with respect to two preclinical research programs to evaluate potential vaccine products for the treatment, cure, diagnosis or prevention of the hepatitis B virus (HBV) and the human immunodeficiency virus (HIV). The Company’s performance obligations under the terms of this agreement include one combined performance obligation for each research program (HBV and HIV) comprised of the transfer of intellectual property rights (licenses) and providing research and development services. The licenses do not represent distinct performance obligations, because they cannot be used without the research and development services. Payments to the Company under this agreement include a non-refundable up-front payment, payments for research and development activities, payments based upon the achievement of defined milestones, and if certain future conditions are met, payments for manufacturing services, commercial milestones and royalties on product sales.

The Company evaluates its collaboration and licensing arrangements pursuant to Accounting Standards Codification (ASC) 606. To determine the recognition of revenue from arrangements that fall within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation.

Under ASC 606, the Company applies significant judgement to evaluate whether the obligations under the collaboration and licensing arrangement, represent separate or one or more combined performance obligations, the allocation of the transaction price to identified performance obligations, and the determination of when milestone payments are probable of being received.

Upfront payment

The non-refundable upfront-payment received by the Company under the Gilead agreement is recorded as deferred revenue and allocated between the two research program performance obligations. Such amounts are recognized as revenue over the performance period of the respective services on a percent of completion basis using total estimated research and development labor hours (input method) for each of the obligations. The percent of completion basis using labor hours was considered the best measure of progress in which control of the combined performance obligations transfers to the customer, due to the short time intervals in which research results are shared with the collaboration partner and the nature of the work being performed.

Reimbursement for services

Under the Gilead Agreement, the Company incurs employee expenses as well as external costs for research and manufacturing activities presented as operating expenses or prepaid expenses. Based on the nature of the Company's responsibilities under the collaboration arrangement, reimbursement of those costs are presented as revenue and not deducted from expenses, as the Company controls the research activities. Amounts of consideration allocated to the performance of research or manufacturing services are recognized over the period in which services are performed. Reimbursements for external costs are recognized as revenues in the period in which the goods or services are received and external costs are recognized. Unpaid reimbursement amounts are presented as Accounts receivable.

Research and development milestones

The Gilead Agreement includes contingent milestone payments related to specified preclinical and clinical development milestones. These milestone payments represent variable consideration that are not initially recognized within the transaction price as they are fully constrained under the guidance in ASC 606, due to the scientific uncertainties and the required commitment from Gilead. The Company will continue to assess the probability of significant reversals for any amounts that become likely to be realized prior to recognizing the variable consideration associated with these payments within the transaction price.

Sales-based milestones and royalty payments

The Gilead Agreement also includes certain sales-based milestone and royalty payments upon successful commercialization of a licensed product. In accordance with ASC 606-10-55-65, the Company recognizes revenues from sales-based milestone and royalty payments at the later of (i) the occurrence of the subsequent sale; or (ii) the performance obligation to which some or all of the sales-based milestone or royalty payments has been allocated has been satisfied. The Company anticipates recognizing these milestones and royalty payments if and when subsequent sales are generated from a licensed product by the collaboration partner.

Cost to fulfill contracts

The Company incurs costs for personnel, supplies and other costs related to its laboratory operations as well as fees from third parties and license expenses in connection with its research and development obligations under the collaboration and licensing agreement. These costs are recognized as research and development expenses over the period in which services are performed. Sublicense fees triggered by the receipt of payments are capitalized as an asset when the obligation to pay the fee arises. The capitalized asset is amortized over the period in which the revenue from the triggering payment is recognized.

Redeemable convertible preferred stock

Upon the closing of the Company’s IPO on April 23, 2019, the Company’s outstanding redeemable convertible preferred stock automatically converted into shares of common stock or Class A common stock. Prior to the conversion, the Company had applied the guidance in ASC 480‑10‑S99‑3A, SEC Staff Announcement: Classification and Measurement of Redeemable Securities and had therefore classified the Series A, Series B, Series C and Series D redeemable convertible preferred stock as mezzanine equity. The redeemable convertible preferred stock was recorded outside of stockholders’ equity because, in the event of certain deemed liquidation events considered not solely within the Company’s control, such as a merger, acquisition and sale of all or substantially all of the Company’s assets, the convertible preferred stock would have become redeemable at the option of the holders. In the event of a change of control of the Company, proceeds received from the sale of such shares would have been distributed in accordance with the liquidation preferences set forth in the Company’s preferred stock agreements. The Company has determined not to adjust the carrying values of the redeemable convertible preferred stock to the liquidation preferences of such shares because of the uncertainty of whether or when such an event would occur.

Recent 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.

Adopted as of current period

In August 2018, the FASB issued ASU 2018‑15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350‑40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. The amendments in this update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this update. The standard became effective for the Company beginning on January 1, 2020. The adoption of this standard did not have a material impact on the Company’s consolidated financial statements and related disclosures.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses which was clarified and amended by the issuances of ASUs 2018-19, 2019-04, 2019-05 and 2019-11 in November 2018, April 2019, May 2019 and November 2019, respectively. The new standard requires that expected credit losses relating to financial assets measured on an amortized cost basis are measured using an expected-loss model, replacing the current incurred-loss model, and recorded through an allowance for credit losses. The guidance also establishes a new impairment model for available-for-sale debt securities. The Company adopted the new standard and the related amendments on January 1, 2020, on a modified retrospective basis, to the accounts receivable, contract asset balances and cash equivalents as of January 1, 2020. Under the current expected credit loss model, the Company adopted a provision matrix approach, utilizing historical loss rates based on the number of days past due, adjusted to reflect current economic conditions and forecasts of future economic conditions. The Company has never experienced a credit loss on its accounts receivable, contract assets or on the principal or interest receivable of its cash equivalents. Accordingly, the effect of the adoption on the financial statement line items of accounts receivable, contract assets and cash equivalents was not material as of January 1, 2020. As a result of the adoption, the cumulative-effect adjustment to reflect the incremental estimated lifetime expected credit losses on the accounts receivable balance as of January 1, 2020 is immaterial. Therefore, the Company recognized no cumulative-effect adjustment within retained earnings on its condensed consolidated balance sheet as of January 1, 2020. The Company has not presented the amortized cost basis within each credit quality indicator by year of origination as all of its accounts receivable are due within one year or less.

In August 2018, the FASB issued ASU 2018‑13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, (“ASU 2018‑13”). The new standard removes certain disclosures, modifies certain disclosures and adds additional disclosures related to fair value measurement. The adoption of this guidance on January 1, 2020 did not have a material impact on the Company’s consolidated financial statements.

In November 2018, the FASB issued ASU 2018-18, Clarifying the Interaction Between Topic 808 and 606, which clarifies when transactions between participants in a collaborative arrangement are within the scope of the FASB’s revenue standard, Topic 606. The adoption of this guidance on January 1, 2020 did not have a material impact on the Company’s consolidated financial statements.

Recently Issued Accounting Pronouncements

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), which eliminates certain exceptions related to the general principles in ASC 740 and makes amendments to other areas with the intention of simplifying various aspects related to accounting for income taxes. The pronouncement is effective for fiscal years, and for interim periods within those fiscal years beginning after December 15, 2020, with early adoption permitted. The Company is currently evaluating the potential impact of the adoption of these updates on its consolidated financial statements.

In March 2020, the FASB issued guidance which provides optional expedients and exceptions to address the impact of reference rate reform where contracts, hedging relationships and other transactions that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate need to be discontinued. This guidance was effective upon issuance and generally can be applied through December 31, 2022. The Company is currently assessing the impact that this guidance will have on its consolidated financial statements.

In August 2018, the FASB issued guidance which modifies the disclosure requirements for defined benefit pension plans and other postretirement plans. The guidance removes disclosures that no longer are considered cost beneficial, clarifies the specific requirements of disclosures, and adds disclosure requirements identified as relevant. This guidance is effective for fiscal years ending after December 15, 2020. Early adoption is permitted. The Company is currently assessing the impact that this guidance will have on its consolidated financial statements, however believes that the adoption of this guidance will not have a material impact on its consolidated financial statements.

Collaboration and Licensing Agreements	6 Months Ended
Collaboration and Licensing Agreements	Jun. 30, 2020
Collaboration and Licensing Agreements
Collaboration and Licensing Agreements	3. Collaboration and Licensing Agreements Gilead Collaboration and License Agreement In June 2018, the Company entered into the Gilead Agreement whereby the Company and Gilead agreed to collaborate with respect to two preclinical research programs to evaluate potential vaccine products for the treatment, cure, diagnosis or prevention of HBV and HIV. Under the Gilead Agreement, the Company granted Gilead an exclusive, royalty-bearing license to the Company’s technology platforms. Upon entering into the agreement, the Company received a non-refundable $10.0 million upfront payment from Gilead. Gilead is also obligated to make additional payments to the Company upon the achievement of pre-clinical, development and commercial milestones. The development milestones amount to a total of $280 million. The commercial milestones amount to a total of $100 million. Additionally, Gilead is obligated to pay royalties on net sales for each program. All payments from Gilead have a 60 days payment term. The $10.0 million upfront payment received in 2018 and a $4.0 million milestone payment received in the six months ended June 30, 2020 were initially recorded as deferred revenue in the consolidated balance sheet and are recognized as revenue when revenue recognition criteria are met. As of June 30, 2020, $4.1 million of upfront and milestone payments were included as a liability in deferred revenues, current and non-current. Approximately 56% of deferred revenue as of June 30, 2020 is expected to be recognized as revenue in the remainder of 2020, 38% in 2021 and the remaining 5% in 2022. In the three months ended June 30, 2020, the Company recognized $1.0 million of the upfront payment received in 2018 and $0.6 million of the $4.0 million milestone payment received earlier in 2020. In addition, the Company fully recognized a $1.0 million milestone payment for a milestone achieved in the three months ended June 30, 2020 and $4.1 million revenue from cost reimbursements for research and development services. For the three months ended June 30, 2019, revenue from reimbursement of research and development expenses was $0.7 million, and revenue from partial recognition of the upfront payment was $1.4 million. Additionally, the Company recognized a $2.0 million milestone payment for a milestone achieved in the three months ended June 30, 2019. In the six months ended June 30, 2020, the Company recognized $1.4 million of the upfront payment received in 2018 and $1.2 million of the $4.0 million milestone payment received earlier in 2020. In addition, the Company fully recognized a $1.0 million milestone payment for a milestone achieved in the six months ended June 30, 2020 and $6.8 million revenue from cost reimbursements for research and development services. For the six months ended June 30, 2019, revenue from reimbursement of research and development expenses was $2.0 million, and revenue from partial recognition of the upfront payment was $2.3 million. Additionally, the Company recognized a $2.0 million milestone payment for a milestone achieved in the six months ended June 30, 2019. Sublicense fees payable to certain licensors of technologies upon the receipt of the deferred upfront and milestone payments, were capitalized as a contract asset and will be amortized over the period in which the revenue from the triggering payment is recognized. As of June 30, 2020 and December 31, 2019, the contract asset and the liability relating to the sublicense payment was $0.2 million and $0.3 million, respectively.

Fair Value of Financial Assets

6 Months Ended

Jun. 30, 2020

Fair Value of Financial Assets

Fair Value of Financial Assets

4. Fair Value of Financial Assets

The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicating the level of the fair value hierarchy utilized to determine such fair values (in thousands):


	Fair Value Measurement at June 30, 2020 Using
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	35,384	$	—	$	—	$	35,384
Total	$	35,384	$	—	$	—	$	35,384


	Fair Value Measurement at December 31, 2019 Using
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	35,132	$	—	$	—	$	35,132
Total	$	35,132	$	—	$	—	$	35,132

During the six months ended June 30, 2020, there were no transfers between Level 1, Level 2 and Level 3.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Accrued expenses and other current liabilities

6 Months Ended

Jun. 30, 2020

Accrued expenses and other current liabilities

Accrued expenses and other current liabilities

5. Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	June 30,		December 31,
	2020		2019
Consulting fees	$	1,033	$	724
Salaries and bonuses		2,154		2,640
Social security contributions		278		177
Unearned grant income (current)		735		725
Loans		—		1,224
Invoices not yet received		1,023		2,673
Finance lease liabilities		155		159
Other accruals and liabilities		22		84
	$	5,400	$	8,406

Loans payable

6 Months Ended

Jun. 30, 2020

Loans payable

Loans payable

6. Loans payable

As of June 30, 2020 and December 31, 2019, loans payable consisted of the following (in thousands):


	June 30,		December 31,
	2020		2019
Loans from FFG	$	6,031	$	7,305
Unamortized debt discount		(2,213)		(2,586)
Total Loans payable, net	$	3,818	$	4,719

In connection with the funding agreements with the Austrian Research Promotion Agency, (Österreichische Forschungsförderungsgesellschaft, or “FFG”), the Company has received various loans (“FFG Loans”). The FFG Loans were made on a project-by-project basis. Amounts due under the FFG Loans bear interest at rates ranging from 0.75% to 1.0% per annum and mature at various dates between June 2022 and March 2024. Interest on amounts due under the loans is payable semi-annually in arrears, with all principal and remaining accrued interest due upon maturity.

The FFG Loans bear interest at rates that are below market rates of interest. The Company accounts for the imputed benefit arising from the difference between an estimated market rate of interest and the rate of interest charged by FFG as grant income from FFG. On the date that FFG loan proceeds are received, the Company recognizes the portion of the loan proceeds allocated to grant funding as a discount to the carrying value of the loan and as unearned income, which is recognized as grant income over the term of the funding agreement.

In November 2019, the Company agreed to an earlier repayment schedule for $3.3 million of the outstanding loans with FFG. As a result of the change, the Company reduced the deferred income attributable to the imputed benefit from below market interest by $0.3 million and increased the carrying value of the loans by the same amount.

No principal repayment was made in the three months ended June 30, 2020. A principal repayment of $1.3 million was made in the six months ended June 30, 2020. There were no principal payments due or paid under the FFG Loans during the three and six months ended June 30, 2019.

Redeemable convertible preferred stock	6 Months Ended
Redeemable convertible preferred stock	Jun. 30, 2020
Redeemable convertible preferred stock.
Redeemable convertible preferred stock	7. Redeemable convertible preferred stock Redeemable convertible preferred stock The Company previously issued Series A redeemable convertible preferred stock (the “Series A Preferred Stock”), Series B redeemable convertible preferred stock (the “Series B Preferred Stock”), Series C redeemable convertible preferred stock (the “Series C Preferred Stock”) and Series D redeemable convertible preferred stock (the “Series D Preferred Stock” and together with the Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock, the “Preferred Stock”). Upon the closing of the Company’s IPO in April 2019, the Company’s outstanding redeemable convertible preferred stock automatically converted into shares of common stock or, if elected by the holder, into Class A common stock. Prior to conversion, the Preferred Stock had certain contingent redemption features based upon the occurrence of events that were not solely within the control of the Company and was therefore classified as mezzanine equity. In February 2019, the Company issued and sold 257,000 shares of Series D Preferred Stock at an average price of $145.65 per share for gross proceeds of $37.4 million. The Company incurred issuance costs in connection with the Series D Preferred Stock of $0.2 million. Upon issuance of each class of Preferred Stock, the Company assessed the embedded conversion and liquidation features of the shares and determined that such features did not require the Company to separately account for these features. The Company also concluded that no beneficial conversion feature existed on the issuance date of each class of Preferred Stock. Upon the closing of the Company’s IPO, all 1,580,506 then outstanding shares of Preferred Stock converted into 14,582,161 shares of common stock and 3,819,732 shares of Class A common stock. The related book value of $142.0 million was reclassified to common stock and additional paid-in capital. As of June 30, 2020 and 2019, the Company had no shares of Preferred Stock outstanding. The Company is authorized to issue 10,000,000 shares of undesignated preferred stock.

Common stock and Class A common stock	6 Months Ended
Common stock and Class A common stock	Jun. 30, 2020
Common stock and Class A common stock
Common stock and Class A common stock	8. Common stock and Class A common stock In June 2018, the Company became the reporting entity in a transaction between entities under common control. In the accompanying condensed consolidated financial statements and notes, the common stock is retrospectively presented as if the Company had been the reporting entity for all periods during which the previous reporting entity was under common control. On April 23, 2019, the Company closed its IPO of 6,000,000 shares of common stock, at an offering price to the public of $14.00 per share. The Company received net proceeds of $74.6 million, after deducting $9.4 million in underwriting discounts and commissions and offering expenses. Upon the closing of the Company’s IPO, all then outstanding shares of Preferred Stock converted into 14,582,161 shares of common stock and 3,819,732 shares of Class A common stock. As of June 30, 2020, the Company was authorized to issue 100,000,000 shares of common stock and 3,900,000 shares of Class A common stock and had 21,834,692 shares of common stock and 3,819,732 shares of Class A common stock outstanding and issued. Holders of common stock are entitled to one vote for each share held on all matters submitted to a vote of the stockholders. The holders of Class A common stock are not entitled to vote, except as required by law. Each holder of Class A common stock has the right to convert each share of Class A common stock into one share of common stock at such holder's election. The holders of common stock and Class A common stock do not have any cumulative voting rights. Subject to any preferential dividend rights of any outstanding preferred stock, holders of common stock and Class A common stock are entitled to receive ratably any dividends declared by the board of directors out of funds legally available for that purpose. Holders of common stock and Class A common stock have no preemptive rights, conversion rights, or other subscription rights or redemption or sinking fund provisions. In the event of a liquidation, dissolution, or winding up of the Company, holders of common stock and Class A common stock will be entitled to share ratably in all assets remaining after payment of all debts and other liabilities, subject to the preferences that may be applicable to any outstanding shares of preferred stock.

Stock-based compensation

6 Months Ended

Jun. 30, 2020

Stock-based compensation

Stock-based compensation

9. Stock-based compensation

2018 Stock Option and Grant Plan

In connection with a transaction between entities under common control by which the Company became the reporting entity in June 2018, the Board of Directors approved the 2018 Stock Option and Grant Plan, by which options granted by the previous reporting entity under the 2016 Stock Option Plan and outstanding at the time of the effectiveness of the transaction were replaced at similar commercial terms. In the accompanying condensed consolidated financial statements and notes, options issued under previous stock option plans and respective compensation expenses are retrospectively presented as if such options had been issued and outstanding under the 2018 Stock Option and Grant Plan for all periods during which the previous reporting entity was under common control.

The exercise price for options granted as a replacement of the 2016 Stock Option Plan is the U.S. dollar equivalent of €0.09, except for 23,286 options granted to an US employee, for which the exercise price is $2.93 following a repricing of these options in December 2018. For any new options, the exercise price shall not be less than 100% of the fair market value of the common stock on the grant date.

Options granted under the 2018 Stock Option and Grant Plan generally vest over four years, with 25% of the options vesting upon the first anniversary of the grant date and the remaining 75% of the options vesting in 12 equal quarterly installments following the first anniversary of the grant date, provided the option holder continues to have an employment or service relationship with the Company on each vesting date. The options expire on the 10th anniversary of the grant date. As of June 30, 2020, 1,265,839 options granted under the 2018 Stock Option and Grant Plan remained outstanding. Any authorization to issue new options under the 2018 Stock Option and Grant Plan was cancelled upon the effectiveness of the 2019 Stock Option and Incentive Plan and no further awards will be granted under the 2018 Plan.

2019 Stock Option and Incentive Plan

On April 1, 2019, the Company’s stockholders approved the 2019 Stock Option and Incentive Plan, which became effective as of the effective date of the registration statement in connection with the Company’s IPO. The maximum number of shares of the Company’s common stock that may be issued under the Company’s 2019 Stock Option and Incentive Plan is 3,630,686, shares which shall be cumulatively increased each year by up to 4% of the then outstanding number of shares. Options granted under the 2019 Stock Option and Incentive Plan generally vest over four years, with 25% of the options vesting upon the first anniversary of the grant date and the remaining 75% of the options vesting in 12 equal quarterly installments following the first anniversary of the grant date, provided the option holder continues to have an employment or service relationship with the Company on each vesting date. Initial options granted to non-executive directors upon their election generally vest over a three-year term with 33% of the options vesting upon the first anniversary of the grant date and the remaining 67% of the options vesting in eight equal quarterly installments following the first anniversary of the grant date. Option re-grants to non-executive directors generally vest on the first anniversary of the grant date. The options expire on the 10th anniversary of the grant date. For each option, the beneficiary is entitled to receive one share of common stock upon the exercise of the option.

Stock option valuation

The Company estimates the option’s fair value on the date of grant using the Black-Scholes option-pricing model. Black-Scholes utilizes assumptions related to expected term, volatility, the risk-free interest rate, the dividend and employee exercise behavior. Forfeitures are accounted for when they occur. Expected volatilities utilized in the Black-Scholes model are based on historical volatilities of a group of comparable companies. The group of representative companies have characteristics similar to the Company, including the stage of product development and focus of the life science industry. Management believes that this represents the most accurate basis for estimating expected future volatilities under the current conditions. The risk-free interest rate is derived from the yields for U.S. Treasuries with a remaining term approximating the expected life of the options. The expected term represents the period of time that the options granted are expected to be outstanding.

The following table summarizes the assumptions used in the Black-Scholes option-pricing model for estimating the fair value of stock options granted during:



	Three and six months ended June 30,
	2020		2019

Risk-free interest rate	0.44	%	2.45	%
Expected term (in years)	6.0		6.1
Expected volatility	79.0	%	73.5	%
Expected dividends	—	%	—	%

For the 2020 and 2019 grants, the Company used the simplified method in developing an estimate of the expected term due to a lack of historical exercise data.

Stock option activity

The following table summarizes the Company’s stock option activity since January 1, 2020 (in thousands, except share and per share amounts):


				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value
				(in years)
Outstanding as of December 31, 2019	2,999,284	$	7.63	8.1	$	15,840
Granted	739,928		8.34
Exercised	(88,300)		0.16
Forfeited	(64,941)		9.40
Outstanding as of June 30, 2020	3,585,971	$	7.93	8.1	$	15,945

Options exercisable as of June 30, 2020	1,223,596	$	4.30	6.6	$	9,659
Options unvested as of June 30, 2020	2,362,375	$	9.80	8.9	$	6,286

The aggregate intrinsic value of stock options was calculated as the difference between the exercise price of the stock options and the estimated fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The estimated fair value per common stock used for calculating the intrinsic values as of June 30, 2020 and December 31, 2019, was $11.62 and $12.23, respectively.

Cash received from option exercise under share-based payment arrangements for the six months ended June 30, 2020 was $15 thousand. No cash from option exercise was received in the six months ended June 30, 2019.

Stock-based compensation

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands):


	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
Research and development expenses	$	771	$	401	$	1,448	$	662
General and administrative expenses		1,380		805		2,797		927
	$	2,151	$	1,206	$	4,245	$	1,589

Income taxes	6 Months Ended
Income taxes	Jun. 30, 2020
Income taxes
Income taxes	10. Income taxes Income tax expense during the three and six months ended June 30, 2020 and 2019 resulted from minimum tax obligations. During the three and six months ended June 30, 2020 and 2019, the Company recorded no income tax benefits for the net operating losses incurred, due to its uncertainty of realizing a benefit from those items. The Company’s losses before income taxes were generated in the United States and Austria. The Company has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets resulting from its net operating loss carryforwards. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of commercialization of any products or generation of any revenue from product sales since inception and has concluded that it is more likely than not that the Company will not realize the benefits of its deferred tax assets. Accordingly, a full valuation allowance has been established against the deferred tax assets as of June 30, 2020 and December 31, 2019. Management reevaluates the positive and negative evidence at each reporting period.

Commitments and contingencies	6 Months Ended
Commitments and contingencies	Jun. 30, 2020
Commitments and contingencies
Commitments and contingencies	11. Commitments and contingencies Operating and Finance Leases The Company leases real estate, including office and laboratory space and has entered into various other agreements with respect to assets used in conducting its business. The Company is required to maintain a cash balance of $0.4 million to secure letters of credit associated with real estate leases. This amount was classified as non-current restricted cash in the Company’s condensed consolidated balance sheet as of June 30, 2020. As of June 30, 2020 and December 31, 2019, the Company’s operating lease right-of-use assets were $6.9 million and $7.9 million, respectively, which are reported in operating lease right-of-use assets in the Company’s condensed consolidated balance sheets. As of June 30, 2020 and December 31, 2019, the Company’s finance lease right-of-use assets were $1.4 million and $1.6 million, respectively, which are reported in finance lease right-of-use assets in the Company’s condensed consolidated balance sheets. As of June 30, 2020, the Company had outstanding operating lease obligations of $6.2 million, of which $1.8 million is reported in operating lease liabilities, current portion and $4.4 million is reported in operating lease liabilities, non-current portion in the Company’s condensed consolidated balance sheets. As of June 30, 2020, the Company had outstanding finance lease obligations of $0.5 million, of which $0.2 million is reported in accrued expenses and other current liabilities and $0.3 million is reported in other non-current liabilities in the Company’s condensed consolidated balance sheets. As of December 31, 2019, the Company had outstanding operating lease obligations of $7.1 million, of which $1.8 million is reported in operating lease liabilities, current portion and $5.3 million is reported in operating lease liabilities, non-current portion in the Company’s condensed consolidated balance sheets. As of December 31, 2019, the Company had outstanding finance lease obligations of $0.5 million, of which $0.2 million is reported in accrued expenses and other current liabilities and $0.3 million is reported in other non-current liabilities in the Company’s condensed consolidated balance sheets. The Company’s weighted average discount rate and weighted average lease term remaining on operating lease liabilities is approximately 2.3% and 3.6 years, respectively. The Company’s weighted average discount rate and weighted average lease term remaining on finance lease liabilities is approximately 1.7% and 3.4 years, respectively. The Company subleases certain of its leased real estate that it does not currently utilize to a third party. The sublease has a remaining lease terms of 0.7 years without an option to renew and has been qualified as an operating lease. Contract manufacturing arrangements The Company has entered into arrangements with contract manufacturing organizations (“CMOs”) for manufacturing of materials for research and development purposes, including manufacturing of clinical trial materials. These contracts generally provide for non-cancellable obligations or cancellation penalties depending on the time of cancellation. As of June 30, 2020, the Company’s total non-cancellable obligations under contracts with CMOs, excluding embedded lease liabilities, were $7.7 million, of which $4.8 million relate to 2020 (remaining six months) deliverables and $2.9 million relate to 2021 deliverables. Intellectual property licenses The Company has entered into certain license agreements under which it is obligated to make milestone payments upon the achievement of certain development and regulatory milestones, to pay royalties on net sales of licensed products, and to pay a percentage of the sublicense fees which the Company receives from its sublicensees. In the three and six months ended June 30, 2020, the Company recorded $0.1 million and $0.2 million, respectively, in licensing fees from intellectual property licenses as research and development expenses. These amounts mainly related to the upfront payment and milestone payments received by the Company under the Gilead Agreement. The amounts recognized as expenses have been agreed to by the licensors but calculation of sublicensing fees on future payments may be subject to interpretation and may change until agreed to by the receiving party. Indemnification agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and senior management that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any claims under indemnification arrangements, and it has not accrued any liabilities related to such obligations in its condensed consolidated financial statements as of June 30, 2020 and December 31, 2019. Legal proceedings At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. While it is not feasible to predict the outcome of these matters with certainty, and some lawsuits, claims or proceedings may be disposed or decided unfavorably, the Company does not expect that any asserted or un-asserted legal claims or proceedings, individually or in the aggregate, will have a material adverse effect on the Company. The Company expenses the costs related to such legal proceedings as incurred.

Net loss per share

6 Months Ended

Jun. 30, 2020

Net loss per share

Net loss per share

12. Net loss per share

The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders (in thousands, except for per share amounts):


	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
Numerator:
Net loss	$	(7,092)	$	(12,079)	$	(18,018)	$	(21,408)

Denominator:
Weighted-average common shares outstanding, basic and diluted		25,647,819		19,240,977		25,638,913		10,174,157

Net loss per share, basic and diluted	$	(0.28)	$	(0.63)	$	(0.70)	$	(2.10)

Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share for all periods as the inclusion of all potential common shares (Common Stock and Class A Common Stock) outstanding would have been anti-dilutive. Potentially dilutive securities as of June 30, 2020 that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:


	Three and six months ended June 30,
	2020	2019
Options issued and outstanding	3,585,971	2,592,955
Total	3,585,971	2,592,955

Related parties	6 Months Ended
Related parties	Jun. 30, 2020
Related parties
Related parties	13. Related parties Following the expiry of the consultancy agreement between the Company and its Chief Scientific Officer, Daniel Pinschewer, on March 19, 2020 the Company entered into a new consultancy agreement with Daniel Pinschewer on March 20, 2020, pursuant to which he will serve as Scientific Advisor to the Chief Executive Officer. The Company is party to research and service arrangements with the University of Basel. Daniel Pinschewer, formerly Chief Scientific Officer, and his spouse are employees of the University of Basel and both involved in providing the services under these arrangements. In the three months ended June 30, 2020, the Company recorded no related party transactions. In the three months ended June 30, 2019, the Company recorded less than $0.1 million, in the six months ended June 30, 2020 and 2019, the Company recorded $0.3 million and $0.3 million, respectively, in research and development expenses for service fees paid to the University of Basel, which represented related party transactions. The University of Basel is also entitled to receive de minimis royalties on the net sales of any product that is based on a patent created by Daniel Pinschewer in the course of his consulting services to the Company. In the three and six months ended June 30, 2020 and 2019, no royalties were paid pursuant to the terms of this arrangement. During the six months ended June 30, 2019, the Company issued 50,670 shares of Series D Preferred Stock for total gross proceeds of $7.4 million and 1,303,750 shares of common stock as part of the Company’s IPO for total gross proceeds of $18.3 million to certain stockholders that were related parties.

Subsequent events	6 Months Ended
Subsequent events	Jun. 30, 2020
Subsequent events.
Subsequent events	14. Subsequent events Stock option grant On July 20, 2020, the Company granted options to employees to purchase 79,104 shares of common stock. All options granted on July 20, 2020 vest over four years, with 25% of the options vesting on May 15, 2021 and the remaining 75% of the options vesting in 12 equal quarterly installments following the first anniversary of the vesting date, provided the option holder continues to have an employment relationship with the Company on each vesting date. Restricted stock units grant On July 20, 2020, the Company granted 44,308 restricted stock units to certain executive officers and employees, vesting in four equal installments on March 20, 2021, May 15, 2021, August 15, 2021 and November 15, 2021. .

Summary of significant accounting policies (Policies)

6 Months Ended

Jun. 30, 2020

Summary of significant accounting policies

Basis of presentation

Going concern

Use of estimates

Deferred offering costs

Concentrations of credit risk and of significant suppliers

Cash equivalents

Fair value measurements

Level 1 - Quoted prices in active markets for identical assets or liabilities.

The Company’s cash equivalents are carried at fair value, determined according to the fair value hierarchy described above (see Note 4).

Property and equipment


		Estimated useful life
Leasehold improvements		5 years
Laboratory equipment		3 - 10 years
Furniture and fixtures		3 - 10 years
Computer equipment and software		3 - 4 years

Leases

Revenue recognition from contracts with customers

Upfront payment

Reimbursement for services

Research and development milestones

Sales-based milestones and royalty payments

Cost to fulfill contracts

Redeemable convertible preferred stock

Recent accounting pronouncements

Adopted as of current period

Recently Issued Accounting Pronouncements

Summary of significant accounting policies (Tables)

6 Months Ended

Jun. 30, 2020

Summary of significant accounting policies

Schedule of estimated useful life of each asset


		Estimated useful life
Leasehold improvements		5 years
Laboratory equipment		3 - 10 years
Furniture and fixtures		3 - 10 years
Computer equipment and software		3 - 4 years

Fair Value of Financial Assets (Tables)

6 Months Ended

Jun. 30, 2020

Fair Value of Financial Assets

Schedule of financial assets measured at fair value on a recurring basis


	Fair Value Measurement at June 30, 2020 Using
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	35,384	$	—	$	—	$	35,384
Total	$	35,384	$	—	$	—	$	35,384


	Fair Value Measurement at December 31, 2019 Using
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	35,132	$	—	$	—	$	35,132
Total	$	35,132	$	—	$	—	$	35,132

Accrued expenses and other current liabilities (Tables)

6 Months Ended

Jun. 30, 2020

Accrued expenses and other current liabilities

Schedule of accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	June 30,		December 31,
	2020		2019
Consulting fees	$	1,033	$	724
Salaries and bonuses		2,154		2,640
Social security contributions		278		177
Unearned grant income (current)		735		725
Loans		—		1,224
Invoices not yet received		1,023		2,673
Finance lease liabilities		155		159
Other accruals and liabilities		22		84
	$	5,400	$	8,406

Loans payable (Tables)

6 Months Ended

Jun. 30, 2020

Loans payable

Schedule of loans payable

As of June 30, 2020 and December 31, 2019, loans payable consisted of the following (in thousands):


	June 30,		December 31,
	2020		2019
Loans from FFG	$	6,031	$	7,305
Unamortized debt discount		(2,213)		(2,586)
Total Loans payable, net	$	3,818	$	4,719

Stock-based compensation (Tables)

6 Months Ended

Jun. 30, 2020

Stock-based compensation

Schedule of assumptions used in the Black-Scholes option-pricing model for estimating the fair value of stock options



	Three and six months ended June 30,
	2020		2019

Risk-free interest rate	0.44	%	2.45	%
Expected term (in years)	6.0		6.1
Expected volatility	79.0	%	73.5	%
Expected dividends	—	%	—	%

Schedule of summary of stock option activity

The following table summarizes the Company’s stock option activity since January 1, 2020 (in thousands, except share and per share amounts):


				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value
				(in years)
Outstanding as of December 31, 2019	2,999,284	$	7.63	8.1	$	15,840
Granted	739,928		8.34
Exercised	(88,300)		0.16
Forfeited	(64,941)		9.40
Outstanding as of June 30, 2020	3,585,971	$	7.93	8.1	$	15,945

Options exercisable as of June 30, 2020	1,223,596	$	4.30	6.6	$	9,659
Options unvested as of June 30, 2020	2,362,375	$	9.80	8.9	$	6,286

Schedule of stock-based compensation expense

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands):


	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
Research and development expenses	$	771	$	401	$	1,448	$	662
General and administrative expenses		1,380		805		2,797		927
	$	2,151	$	1,206	$	4,245	$	1,589

Net loss per share (Tables)

6 Months Ended

Jun. 30, 2020

Net loss per share

Schedule of basic and diluted net loss per share

The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders (in thousands, except for per share amounts):


	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
Numerator:
Net loss	$	(7,092)	$	(12,079)	$	(18,018)	$	(21,408)

Denominator:
Weighted-average common shares outstanding, basic and diluted		25,647,819		19,240,977		25,638,913		10,174,157

Net loss per share, basic and diluted	$	(0.28)	$	(0.63)	$	(0.70)	$	(2.10)

Schedule of potentially dilutive securities that were not included in the diluted per share calculations


	Three and six months ended June 30,
	2020	2019
Options issued and outstanding	3,585,971	2,592,955
Total	3,585,971	2,592,955

Summary of significant accounting policies - Going concern, Cash equivalents and Deferred offering costs (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Summary of significant accounting policies
Net losses	$ 7,092	$ 10,926	$ 12,079	$ 9,329	$ 18,018	$ 21,408	$ 43,000
Accumulated deficit	$ 121,037				$ 121,037		$ 103,019

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Summary of significant accounting policies - Property and equipment (Details)	6 Months Ended
	Jun. 30, 2020
Leasehold improvements
Property and equipment
Estimated useful life	5 years
Laboratory equipment \| Minimum
Property and equipment
Estimated useful life	3 years
Laboratory equipment \| Maximum
Property and equipment
Estimated useful life	10 years
Furniture and fixtures \| Minimum
Property and equipment
Estimated useful life	3 years
Furniture and fixtures \| Maximum
Property and equipment
Estimated useful life	10 years
Computer equipment and software \| Minimum
Property and equipment
Estimated useful life	3 years
Computer equipment and software \| Maximum
Property and equipment
Estimated useful life	4 years

Summary of significant accounting policies - Revenue recognition from contracts with customers (Details)	6 Months Ended
	Jun. 30, 2020 item Program
Summary of significant accounting policies
Number of preclinical research programs \| Program	2
Number of combined performance obligation for each research program	1
Number of research program performance obligations	2

Summary of significant accounting policies - Recent accounting pronouncements (Details) $ in Thousands	Jan. 01, 2020 USD ($)
ASU 2016-13 \| Accumulated Deficit
Summary of significant accounting policies
Cumulative-effect adjustment	$ 0

Collaboration and Licensing Agreements (Details) - Gilead Collaboration and License Agreement $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) item	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Collaboration and Licensing Agreements
Number of preclinical research programs \| item	2
Non-refundable, upfront payment	$ 10.0
Milestone payment received		$ 4.0		$ 4.0
Upfront payment recorded as revenue		1.0	$ 1.4	1.4	$ 2.3
Revenue recognized from milestone payments		1.0	2.0	1.0	2.0
Liability in deferred revenues		4.1		$ 4.1
Percentage of upfront payment included in deferred revenue expected to be recognized in 2020				56.00%
Percentage of upfront payment included in deferred revenue expected to be recognized in 2021				38.00%
Percentage of upfront payment included in deferred revenue expected to be recognized in 2022				5.00%
Payment term (in days)				60 days
Revenue recognized from cost reimbursements		4.1	$ 0.7	$ 6.8	$ 2.0
Upfront payment recorded as revenue		0.6		1.2
Contract asset relating to the sublicense payment		0.2		0.2		$ 0.3
Contract liability relating to sublicense payment		$ 0.2		0.2		$ 0.3
Development Milestones
Collaboration and Licensing Agreements
Total milestone amount				280.0
Commercial Milestones
Collaboration and Licensing Agreements
Total milestone amount				$ 100.0

Fair Value of Financial Assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Fair Value of Financial Assets
Transfers from Level 1 to Level 2	$ 0
Transfers from Level 2 to Level 1	0
Transfers from into Level 3	0
Transfers from out of Level 3	0
Recurring
Fair Value of Financial Assets
Total	35,384	$ 35,132
Recurring \| Money market funds
Fair Value of Financial Assets
Cash equivalents	35,384	35,132
Recurring \| Level 1
Fair Value of Financial Assets
Total	35,384	35,132
Recurring \| Level 1 \| Money market funds
Fair Value of Financial Assets
Cash equivalents	$ 35,384	$ 35,132

Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued expenses and other current liabilities
Consulting fees	$ 1,033	$ 724
Salaries and bonuses	2,154	2,640
Social security contributions	278	177
Unearned grant income (current)	735	725
Loans		1,224
Invoices not yet received	1,023	2,673
Finance lease liabilities	155	159
Other accruals and liabilities	22	84
Total	$ 5,400	$ 8,406

Loans payable (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
Loans payable (Details) - USD ($) $ in Thousands	Nov. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Loans payable
Loans from FFG		$ 6,031		$ 6,031		$ 7,305
Unamortized debt discount		(2,213)		(2,213)		(2,586)
Total Loans payable, net		3,818		3,818		$ 4,719
Scheduled early repayment	$ 3,300
Principal payment		$ 0	$ 0	$ 1,256	$ 0
Adjustment
Loans payable
Deferred income reduced	$ 300
Minimum
Loans payable
Interest rate (as a percent)		0.75%		0.75%
Maximum
Loans payable
Interest rate (as a percent)		1.00%		1.00%

Redeemable convertible preferred stock (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended
	Apr. 23, 2019	Feb. 28, 2019	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Redeemable convertible preferred stock
Average price (in dollars per sale)				$ 11.62	$ 12.23
Amount reclassified upon conversion of Preferred Stock			$ 142,048
Preferred Stock outstanding (in shares)			0	0
Undesignated Preferred Stock authorized (in shares)				10,000,000
IPO
Redeemable convertible preferred stock
Outstanding shares of Preferred Stock converted (in shares)	1,580,506
Amount reclassified upon conversion of Preferred Stock	$ 142,000
Common Stock \| IPO
Redeemable convertible preferred stock
Average price (in dollars per sale)	$ 14.00
Issuance costs	$ 9,400
Stock issued upon conversion of Preferred Stock (in shares)	14,582,161
Series D Preferred Stock
Redeemable convertible preferred stock
Preferred Stock issued (in shares)		257,000
Average price (in dollars per sale)		$ 145.65
Gross Proceeds from issuance of stock		$ 37,400
Issuance costs		$ 200
Class A common stock \| IPO
Redeemable convertible preferred stock
Stock issued upon conversion of Preferred Stock (in shares)	3,819,732
Class A common stock \| Common Stock
Redeemable convertible preferred stock
Stock issued upon conversion of Preferred Stock (in shares)			3,819,732
Amount reclassified upon conversion of Preferred Stock			$ 0

Common stock and Class A common stock (Details) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
	Apr. 23, 2019 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2020 Vote $ / shares shares	Dec. 31, 2019 $ / shares shares
Share Price \| $ / shares			$ 11.62	$ 12.23
Number of votes \| Vote			1
Common stock
Common stock, issued (in shares)			21,834,692	21,746,392
Common stock, outstanding (in shares)			21,834,692	21,746,392
Common stock, shares authorized			100,000,000	100,000,000
Class A common stock
Common stock, issued (in shares)			3,819,732	3,819,732
Common stock, outstanding (in shares)			3,819,732	3,819,732
Common stock, shares authorized			3,900,000	3,900,000
Number of common stock issued upon conversion of each share			1
Common Stock \| Common stock
Issuance of common stock upon initial public offering		6,000,000
Stock issued upon conversion of Preferred Stock (in shares)		14,582,161
Common Stock \| Class A common stock
Stock issued upon conversion of Preferred Stock (in shares)		3,819,732
IPO \| Common stock
Share Price \| $ / shares		$ 14.00
Offering costs \| $		$ 9,386
Stock issued upon conversion of Preferred Stock (in shares)	14,582,161
IPO \| Class A common stock
Stock issued upon conversion of Preferred Stock (in shares)	3,819,732
IPO \| Common Stock
Issuance of common stock upon initial public offering	6,000,000
Share Price \| $ / shares	$ 14.00
Proceeds from Issuance Initial Public Offering \| $	$ 74,600
Offering costs \| $	$ 9,400
Stock issued upon conversion of Preferred Stock (in shares)	14,582,161

Stock-based compensation - 2018 Stock Option and Grant Plan (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2020 installment € / shares shares	Dec. 31, 2018 shares	Dec. 31, 2019 shares
Stock-based compensation
Issuance of common stock upon exercise of stock options (in shares)	88,300
Number of shares granted to US employee	739,928
Options outstanding	3,585,971		2,999,284
2018 Stock Option and Grant Plan
Stock-based compensation
Options outstanding	1,265,839
Vesting period	4 years
2018 Stock Option and Grant Plan \| Vesting upon first anniversary
Stock-based compensation
Percentage of options vesting	25.00%
2018 Stock Option and Grant Plan \| Vesting in equal quarterly installments
Stock-based compensation
Percentage of options vesting	75.00%
Number of quarterly installments for vesting \| installment	12
2016 Stock Option Plan
Stock-based compensation
Percentage of share price with fair market value	100.00%
2016 Stock Option Plan \| Exercise price 0.09 euros
Stock-based compensation
Exercise price for options granted as a replacement \| € / shares	€ 0.09
Number of shares granted to US employee	23,286
2016 Stock Option Plan \| Exercise price $2.93
Stock-based compensation
Number of shares granted to US employee		2.93

Stock-based compensation - 2019 Stock Option and Incentive Plan (Details)	Apr. 01, 2019 installment shares
Stock-based compensation
Number of common stock entitled for each option upon the exercise of the option \| shares	1
2019 Stock Option and Incentive Plan
Stock-based compensation
Number stock option authorized \| shares	3,630,686
Number of shares outstanding were cumulatively increased	4.00%
Vesting period	4 years
2019 Stock Option and Incentive Plan \| Non Executive Directors
Stock-based compensation
Vesting period	3 years
2019 Stock Option and Incentive Plan \| Vesting upon first anniversary
Stock-based compensation
Percentage of options vesting	25.00%
2019 Stock Option and Incentive Plan \| Vesting upon first anniversary \| Non Executive Directors
Stock-based compensation
Percentage of options vesting	33.00%
2019 Stock Option and Incentive Plan \| Vesting in equal quarterly installments
Stock-based compensation
Percentage of options vesting	75.00%
Number of quarterly installments for vesting \| installment	12
2019 Stock Option and Incentive Plan \| Vesting in equal quarterly installments \| Non Executive Directors
Stock-based compensation
Percentage of options vesting	67.00%
Number of quarterly installments for vesting \| installment	8

Stock-based compensation - Stock option valuation (Details)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Assumptions used in the Black-Scholes option-pricing model
Risk-free interest rate	0.44%	2.45%
Expected term (in years)	6 years	6 years 1 month 6 days
Expected volatility	79.00%	73.50%

Stock-based compensation - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Number of Shares
Beginning balance	2,999,284
Granted	739,928
Exercised	(88,300)
Forfeited	(64,941)
Ending balance	3,585,971		2,999,284
Option exercisable	1,223,596
Option unvested	2,362,375
Weighted Averaged Exercise Price
Beginning balance	$ 7.63
Granted	8.34
Exercised	0.16
Forfeited	9.40
Ending balance	7.93		$ 7.63
Option exercisable	4.30
Option unvested	$ 9.80
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term (in years)	8 years 1 month 6 days		8 years 1 month 6 days
Weighted Average Remaining Contractual Term, option exercisable	6 years 7 months 6 days
Weighted Average Remaining Contractual Term, option unvested	8 years 10 months 24 days
Aggregate Intrinsic Value, beginning balance	$ 15,840
Aggregate Intrinsic Value, ending balance	15,945		$ 15,840
Aggregate Intrinsic Value, option exercisable	6,286
Aggregate Intrinsic Value, option unvested	$ 9,659
Average price (in dollars per sale)	$ 11.62		$ 12.23
Cash received from option exercise under share-based payment arrangements	$ 15	$ 0

Stock-based compensation - Stock-based compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock-based compensation
Stock-based compensation expense	$ 2,151	$ 1,206	$ 4,245	$ 1,589
Research and Development Expense
Stock-based compensation
Stock-based compensation expense	771	401	1,448	662
General and Administrative Expense
Stock-based compensation
Stock-based compensation expense	$ 1,380	$ 805	$ 2,797	$ 927

Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Income taxes (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income taxes
Income tax benefits for the net operating losses incurred	$ 0	$ 0	$ 0	$ 0

Commitments and contingencies - Operating and Finance Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Commitments and contingencies
Cash balance maintained to secure a letter of credit associated with a real estate lease	$ 425	$ 424
Operating lease right-of-use assets	6,949	7,875
Finance lease right-of-use assets	1,399	1,602
Outstanding operating lease obligations	6,200	7,100
Current operating lease liability	1,841	1,814
Non-current operating lease liability	4,398	5,290
Outstanding finance lease obligations	500	500
Current finance lease liability	$ 155	$ 159
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Expenses and Other Current Liabilities.	Hook:AccruedExpensesAndOtherCurrentLiabilities
Non-current finance lease liability	$ 300	$ 300
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Weighted average discount rate on operating lease liabilities (as a percent)	2.30%
Weighted average lease term remaining on operating lease liabilities (in years)	3 years 7 months 6 days
Weighted average discount rate on finance lease liabilities (as a percent)	1.70%
Weighted average lease term remaining on finance lease liabilities (in years)	3 years 4 months 24 days
Sublease, remaining lease term (in years)	8 months 12 days

Commitments and contingencies - Others (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Commitments and contingencies
Non-cancellable obligations	$ 7.7	$ 7.7
2020 deliverables (remaining six months)	4.8	4.8
2021 deliverables	2.9	2.9
Licensing fees from intellectual property licenses	$ 0.1	$ 0.2

Net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Numerator:
Net loss	$ (7,092)	$ (10,926)	$ (12,079)	$ (9,329)	$ (18,018)	$ (21,408)	$ (43,000)
Denominator:
Weighted-average common shares outstanding, basic and diluted	25,647,819		19,240,977		25,638,913	10,174,157
Net loss per share, basic and diluted (in USD per share)	$ (0.28)		$ (0.63)		$ (0.70)	$ (2.10)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Net loss per share - Antidilutive securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Anti-dilutive securities
Anti-dilutive shares	3,585,971	2,592,955	3,585,971	2,592,955
Options
Anti-dilutive securities
Anti-dilutive shares	3,585,971	2,592,955	3,585,971	2,592,955

Related parties (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Related parties (Details) - USD ($) $ in Millions	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Series D Preferred Stock
Related parties
Preferred shares issued				50,670
Proceeds from common stock issued				$ 7.4
Common stock
Related parties
Shares issued				1,303,750
Proceeds from shares issued				$ 18.3
University of Basel
Related parties
Research and development expenses	$ 0.0		$ 0.3	0.3
Royalties paid	$ 0.0	$ 0.0	$ 0.0	$ 0.0
University of Basel \| Maximum
Related parties
Research and development expenses		$ 0.1

Subsequent events (Details)		6 Months Ended
Subsequent events (Details)	Jul. 20, 2020 installment shares	Jun. 30, 2020 shares
Subsequent events
Granted		739,928
Subsequent events \| Options \| Employee
Subsequent events
Granted	79,104
Vesting period	4 years
Number of quarterly installments of vesting \| installment	12
Subsequent events \| Options \| Employee \| Vesting upon first anniversary
Subsequent events
Vesting percentage	25.00%
Subsequent events \| Options \| Employee \| Vesting in equal quarterly installments
Subsequent events
Vesting percentage	75.00%
Subsequent events \| Restricted stock units
Subsequent events
Granted	44,308
Number of equal installments of vesting \| installment	4