0000950170-24-031156 | 10-K | XBRL Viewer | Arcturus Therapeutics Holdings INC

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Property and Equipment, Net (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 2,957	$ 1,527	$ 1,193

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2020	$ 396,553	$ 26	$ 540,343	$ (143,816)
Balance (in shares) at Dec. 31, 2020		26,192,000
Share-based compensation	28,915		28,915
Issuance of common stock related to acquired in-process research and development	5,000		5,000
Issuance of common stock related to acquired in-process research and development (in shares)		75,000
Issuance of common stock upon exercise of stock options	902		902
Issuance of common stock upon exercise of stock options (in shares)		92,000
Issuance of common stock under equity plans	515		515
Issuance of common stock under equity plans (in shares)		13,000
Net Income (Loss)	(203,674)			(203,674)
Balance at Dec. 31, 2021	228,211	$ 26	575,675	(347,490)
Balance (in shares) at Dec. 31, 2021		26,372,000
Share-based compensation	30,611		30,611
Issuance of common stock upon exercise of stock options	1,730	$ 1	1,729
Issuance of common stock upon exercise of stock options (in shares)		161,000
Issuance of common stock under equity plans	411		411
Issuance of common stock under equity plans (in shares)		22,000
Net Income (Loss)	9,349
Balance at Dec. 31, 2022	270,312	$ 27	608,426	(338,141)
Balance (in shares) at Dec. 31, 2022		26,555,000
Share-based compensation	34,649		34,649
Issuance of common stock upon exercise of stock options	$ 2,668		2,668
Issuance of common stock upon exercise of stock options (in shares)	237,820	238,000
Issuance of common stock under equity plans	$ 609		609
Issuance of common stock under equity plans (in shares)		35,000
Net Income (Loss)	(29,725)			(29,725)
Balance at Dec. 31, 2023	$ 278,513	$ 27	$ 646,352	$ (367,866)
Balance (in shares) at Dec. 31, 2023		26,828,000

Property and Equipment, Net

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

NOTE 6. Property and Equipment, Net

Property and equipment, net consisted of the following:


	December 31,
(in thousands)	2023			2022
Research equipment	$	16,046		$	10,251
Computers and software		1,275			1,154
Office equipment and furniture		958			958
Leasehold improvements		2,655			2,491
Construction in progress		233			3,344
Total	$	21,167		$	18,198
Less accumulated depreciation and amortization		(8,740	)		(5,783	)
Property and equipment, net	$	12,427		$	12,415

Depreciation and amortization expense was $3.0 million, $1.5 million and $1.2 million for the years ended December 31, 2023, 2022 and 2021, respectively. Construction in progress is primarily comprised of research equipment not yet placed in service.

Schedule of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 292,005	$ 391,883	$ 370,492
Restricted cash - current	55,000
Non-current Restricted cash	1,885	2,094	2,077
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 348,890	$ 393,977	$ 372,569	$ 463,002

Share-Based Compensation (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expenses	$ 34,649	$ 30,611	$ 28,915
Research and Development [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expenses	14,950	14,081	14,101
General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expenses	$ 19,699	$ 16,530	$ 14,814

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

Income Taxes (Details 5) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Details 5) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance of unrecognized tax benefits	$ 2.9	$ 2.4
Decrease for prior period tax positions	0.1	(0.5)
Increase for current period tax positions	0.6	1.0
Ending balance of unrecognized tax benefits	$ 3.6	$ 2.9

Accrued Liabilities Detail - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Accrued compensation	$ 5,918	$ 4,038
Cystic Fibrosis Foundation liability	7,633
Income tax payable	641	1,295
Current portion of operating lease liability	$ 4,309	$ 3,884
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total	Total
Clinical trial accruals	$ 2,333	$ 4,531
Vinbiocare contractual liabilities	2,514	7,468
Other accrued research and development expenses	8,533	9,016
Total	$ 31,881	$ 30,232

Related Party Transactions - Equity-Method Investment (Details Textual) - GRI Bio [Member]	Apr. 30, 2023 shares
Related Party Transaction [Line Items]
Number of shares owned	28,125
Percentage of owned shares	1.00%

- Definition

Percentage of investment owned to net assets.

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+ Details

Debt

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Debt

NOTE 7. Debt

Wells Fargo Credit Agreement

On April 21, 2023, the Company’s wholly-owned subsidiary, Arcturus Therapeutics, Inc. entered into a credit agreement with Wells Fargo whereby Wells Fargo will make a $50.0 million revolving credit line available to the Company (the “Loan”) and each Loan evidenced by a revolving line of credit note (the “Note”).

Borrowings under the agreement will bear interest at a rate of 1.00% above either the Daily Simple SOFR or Term SOFR (as such terms are defined in the Note), with “SOFR” being the rate per annum equal to the secured overnight financing rate as administered by the Federal Reserve Bank of New York. If an Event of Default (as defined in the agreement) occurs, then all Loans shall bear interest at a rate equal to 2.00% above the interest rate applicable immediately prior to the occurrence of the Event of Default.

The term of the agreement is two years, with an option for one-year renewals subject to Wells Fargo approval and the Company furnishing to Wells Fargo a non-refundable commitment fee equal to 0.25% of the Loan amount for each such renewal. There is no penalty for terminating the facility prior to the maturity date of the Note. As collateral, the Company has agreed to pledge $55.0 million in cash to be held at the Company’s securities accounts with Wells Fargo Securities, LLC, an affiliate of Wells Fargo, pursuant to a security agreement. No amounts were outstanding as of December 31, 2023.

Manufacturing Supply Agreement

On November 7, 2020, the Company’s wholly-owned subsidiary, Arcturus Therapeutics, Inc., entered into a Manufacturing Support Agreement (the “Support Agreement”) with the Economic Development Board of the

Republic of Singapore (the “EDB”). Pursuant to the Support Agreement, the EDB agreed to make a term loan (the “Singapore Loan”) of S$62.1 million to the Company, subject to the satisfaction of customary deliveries, to support the manufacture of the LUNAR-COV19 vaccine candidate (ARCT-021). The Singapore Loan accrues interest at a rate of 4.5% per annum calculated on a daily basis. The Company elected to borrow the full amount available under the Support Agreement of S$62.1 million ($46.6 million) on January 29, 2021.

During the first quarter of 2023, the EDB agreed to an extension of the reconciliation period to March 22, 2023, with unused funds not utilized for the manufacture of ARCT-021 as of such date returned to the EDB. As of December 31, 2022, the outstanding balance of the Singapore Loan, which includes accrued interest, was $50.4 million of which the Company paid S$22.8 million ($17.1 million) in March 2023. During the first quarter of 2023, the remaining principal portion of the Singapore Loan plus accrued interest, totaling $34.0 million, was forgiven and recorded as a gain on debt extinguishment in the consolidated statement of operations and comprehensive loss.

Total interest expenses related to the Singapore Loan was $0.5 million, $2.1 million and $1.9 million for the year ended December 31, 2023, 2022 and 2021, respectively. As of December 31, 2023, the Company no longer had debt or interest related to this agreement.

Termination of Agreement with Western Alliance Bank

On March 14, 2023, the Loan and Security Agreement, dated as of October 12, 2018 (as amended and supplemented, the “Western Alliance Agreement”) with Western Alliance Bank, an Arizona corporation (“Western Alliance”), was terminated (the “Termination”) upon the receipt by Western Alliance of a payoff amount of approximately $7.4 million from the Company. The Western Alliance Agreement provided for a collateralized term loan in the aggregate principal amount of up to $15.0 million, with interest at a floating rate ranging from 1.25% to 2.75% above the prime rate and a maturity date of October 30, 2023. The payoff amount was made by the Company to Western Alliance from available cash on hand, pursuant to a payoff letter, and included payment of (i) approximately $7.0 million in principal and interest, (ii) $0.3 million fee payable upon prepayment as a result of prior FDA approval of an IND and (iii) de minimis amounts in prepayment charges and various operational fees. The Company was released from all liens under the Western Alliance Agreement.

For the years ended December 31, 2023, 2022 and 2021, the Company recorded interest expense of $0.3 million, $0.9 million and $0.8 million, respectively.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Share-Based Compensation (Details 1) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Number of Shares, Outstanding	6,622,740
Number of Shares, Granted	2,140,206
Number of Shares, Exercised	(237,820)
Number of Shares, Forfeited/cancelled	(553,999)
Number of Shares, Outstanding	7,971,127	6,622,740
Number of Shares, Exercisable December 31, 2023	3,700,692
Number of Shares, Exercisable and expected to vest December 31, 2023	7,971,127
Weighted-Average Exercise Price, Outstanding	$ 34.78
Weighted-Average Exercise Price, Granted	27.38
Weighted-Average Exercise Price, Exercised	11.26
Weighted-Average Exercise Price, Forfeited/cancelled	34.31
Weighted-Average Exercise Price, Outstanding	33.55	$ 34.78
Weighted-Average Exercise Price, Exercisable - December 31, 2023	38.04
Weighted-Average Exercise Price, Exercisable and expected to vest -December 31, 2023	$ 33.55
Weighted-Average Remaining Contractual Term (Years), Outstanding	7 years 10 months 24 days	8 years 2 months 12 days
Weighted-Average Remaining Contractual Term (Years), Exercisable - December 31, 2023	6 years 7 months 6 days
Weighted-Average Remaining Contractual Term (Years), Exercisable and expected to vest - December 31, 2023	7 years 10 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 53,295	$ 10,721
Aggregate Intrinsic Value, Exercisable - December 31, 2023	31,142
Aggregate Intrinsic Value, Exercisable and expected to vest - December 31, 2023	$ 53,295

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Arcturus Therapeutics Holdings Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. These consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States (U.S. GAAP), which requires management to make estimates and assumptions regarding the valuation of certain debt and equity instruments, the equity method investment, share-based compensation, accruals for liabilities, income taxes, revenue and deferred revenue, leases, expense accruals, and other matters that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although these estimates are based on management’s knowledge of current events and actions the Company may undertake in the future, actual results could materially differ from those estimates.

Segment Information

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company and its chief operating decision-maker view the Company’s operations and manage its business in one operating segment which is the research and development of medical applications for the Company’s nucleic acid-focused technology.

Cash and Cash Equivalents

Cash equivalents are short-term highly liquid investments that are readily convertible to cash with original maturities of three months or less at the date of purchase.

Restricted Cash

Restricted cash

Restricted cash includes collateral pledged and held at the Company’s securities accounts pursuant to a security agreement with Wells Fargo Bank, National Association (“Wells Fargo”) (Note 7). At December 31, 2023, such collateral amounted to $55.0 million.

Restricted cash also includes cash required to be set aside as security for lease payments and to maintain a letter of credit for the benefit of the landlord for the Company’s offices. At December 31, 2023 and 2022, the Company had restricted cash of $1.9 million and $2.1 million in conjunction with property leases in San Diego, California, and such restriction is expected to be removed at the end of the lease term.

Fair Value Measurements

Fair value is defined as the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. A hierarchy has been established for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available.

Observable inputs are inputs that market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available under the circumstances. The hierarchy consists of three levels. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

Accounts Receivable

Accounts receivable are recorded at the net invoice value and are non-interest bearing. The Company considers receivables past due based on the contractual payment terms. The Company reserves for specific receivables if collectability is no longer reasonably assured. Estimates for allowances for doubtful accounts are

determined based on existing contractual obligations, historical payment patterns, and individual customer circumstances. The Company reevaluates such reserves on a regular basis and adjusts its reserves as needed. Once a receivable is deemed to be uncollectible, such balance is charged against the reserve. No reserves have been recorded as of December 31, 2023 or 2022.

Concentration of Credit Risk and Significant Customers

Financial instruments, which potentially subject the Company to concentrations of credit risk, consist of cash and cash equivalents. The Company limits its exposure to credit loss by placing its cash and cash equivalents with high credit quality financial institutions in instruments with short maturities.

There were two customers that comprised 100% of the total accounts receivable balance at December 31, 2023 and 2022.

For the year ended December 31, 2023, the Company’s top three customers collectively represented 99% of the Company’s total revenue. For the year ended December 31, 2022, the Company's top five customers collectively represented 99% of the Company’s total revenue. For the year ended December 31, 2021, there were four customers that collectively represented 99% of the Company’s total revenue.

Joint Ventures, Equity Method Investments and Variable Interest Entities

Investments for which the Company exercises significant influence, but does not have control are accounted for under the equity method. Equity method investment activity is related to the Company's joint venture in ARCALIS, Inc. with Axcelead, Inc. The Company’s share of the investees’ results is presented as either income or loss from equity method investees in the accompanying consolidated statements of operations and comprehensive income (loss).

Property and Equipment, net

Property and equipment are stated at cost, net of accumulated depreciation and amortization. The cost of property and equipment is depreciated or amortized using the straight-line method over the respective useful lives of the assets, ranging from three to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the estimated useful life of the asset or the lease term. Long-lived assets, including property and equipment are reviewed for impairment whenever events or circumstances indicate that the carrying amount of these assets may not be recoverable. The determinants used for this evaluation include management’s estimate of an asset’s ability to generate positive income from operations and positive cash flow in future periods, as well as the strategic significance of the assets to the Company’s business objectives. The Company did not recognize any impairment losses for the years ended December 31, 2023, 2022 or 2021.

Comprehensive Income/Loss

Comprehensive income/loss is defined as the change in stockholders’ equity during a period from transactions and other events and circumstances from non-owner sources. There was no other comprehensive loss in the years ended December 31, 2023, 2022 or 2021. There was no income tax effect related to unrealized losses for the years ended December 31, 2023, 2022, or 2021.

Revenue Recognition

At contract inception, the Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808). For collaboration arrangements within the scope of ASC 808 that contain multiple elements, the Company first determines which elements of the collaboration reflect a vendor-customer relationship and are therefore within the scope of ASC 606.

The Company determines revenue recognition for arrangements within the scope of Topic 606 by performing the following five steps: (i) identify the contract; (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.

The terms of the Company’s revenue agreements include license fees, upfront payments, milestone payments, reimbursement for research and development activities, option exercise fees, consulting and related technology transfer fees and royalties on sales of commercialized products. The event-based milestone payments represent variable consideration, and the Company uses the most likely amount method to estimate this variable consideration because the Company will either receive the milestone payment or will not, which makes the potential milestone payment a binary event. The most likely amount method requires the Company to determine the likelihood of earning the milestone payment. Given the high degree of uncertainty around achievement of these milestones, the Company determines the milestone amounts to be fully constrained and does not recognize revenue until the uncertainty associated with these payments is resolved. The Company will recognize revenue from sales-based royalty payments when or as the sales occur. The Company will re-evaluate the transaction price in each reporting period as uncertain events are resolved and other changes in circumstances occur.

A performance obligation is a promise in a contract to transfer a distinct good or service to the collaborative partner and is the unit of account in Topic 606. A contract’s transaction price is allocated to each distinct performance obligation based on relative standalone selling price and recognized as revenue when, or as, the performance obligation is satisfied.

For performance obligations that are recognized over time, the Company measures the progress using an input method. The input methods used are based on the effort expended or costs incurred toward the satisfaction of the performance obligation. The Company estimates the amount of effort expended, including the time estimated it will take to complete the activities, or costs incurred in a given period, relative to the estimated total effort or costs to satisfy the performance obligation. This approach requires the Company to make numerous estimates and use significant judgment. If estimates or judgments change over the course of the collaboration, a cumulative catch up of revenue is recognized in the period such changes are identified.

See “Note 3, Revenue” for specific details surrounding the Company’s arrangements.

Leases

The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For operating leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For the Company's operating leases, if the interest rate used to determine the present value of future lease payments is not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The Company's incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.

See “Note 11, Commitments and Contingencies” for specific details surrounding the Company’s leases.

Research and Development Costs, net

All research and development costs are expensed as incurred. Research and development costs consist primarily of salaries, employee benefits, costs associated with preclinical studies and clinical trials (including amounts paid to clinical research organizations and other professional services), in process research and development expenses and license agreement expenses, net of any grants and prelaunch inventory. Payments made prior to the receipt of goods or services to be used in research and development are capitalized until the goods are received or the services are performed.

The Company records accruals for estimated research and development costs, comprising payments for work performed by third party contractors, laboratories, participating clinical trial sites, and others. Some of these contractors bill monthly based on actual services performed, while others bill periodically based upon achieving certain contractual milestones. For the latter, the Company accrues the expenses as goods or services are used or rendered.

Clinical trial activities performed by third parties are accrued and expensed based upon estimates of the proportion of work completed over the life of the individual clinical trial and patient enrollment rates in accordance with agreements established with Clinical Research Organizations ("CROs") and clinical trial sites. Estimates are determined by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services.

Pre-Launch Inventory

Prior to obtaining initial regulatory approval for an investigational product candidate, the Company expenses costs relating to production of inventory as research and development expense in its consolidated statements of operations and comprehensive income (loss), in the period incurred. When the Company believes regulatory approval and subsequent commercialization of an investigational product candidate is probable, and the Company also expects future economic benefit from the sales of the investigational product candidate to be realized, it will then capitalize the costs of production as inventory.

Share-Based Compensation

The Company recognizes share-based compensation for equity awards granted to employees, consultants, officers and directors as an expense on the statements of operations and comprehensive income (loss). Share-based compensation is recognized over the requisite service period of the individual awards using the straight-line attribution method, which generally equals the vesting period. Employees and officers’ stock options have a ten-year life and generally vest 25% on the first anniversary of the grant and in 1/36th equal installments on each monthly anniversary thereafter, such that options are fully vested on the four-year anniversary of the date of grant. The exercisability and vesting periods of options granted to consultants and directors vary.

The fair value of stock options is estimated using a Black-Scholes valuation model on the date of grant. This method requires certain assumptions be used as inputs, such as the fair value of the underlying common stock, expected term of the option before exercise, expected volatility of the Company’s common stock, expected dividend yield, and a risk-free interest rate. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The expected volatility of stock options is based upon the historical volatility of a peer group of publicly traded companies. The Company has not declared or paid any dividends and does not currently expect to do so in the foreseeable future. The risk-free interest rates used are based on the implied yield currently available in United States Treasury securities at maturity with a term equivalent to the expected term of the stock options. The effect of forfeited awards is recorded when the forfeiture occurs.

Statement of Cash Flows

The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the consolidated balance sheets to the total of such amounts shown in the consolidated statement of cash flows:


	As of December 31,
(in thousands)	2023		2022		2021
Cash and cash equivalents	$	292,005	$	391,883	$	370,492
Restricted cash - current		55,000		—		—
Non-current Restricted cash		1,885		2,094		2,077
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$	348,890	$	393,977	$	372,569

Income Tax Expense

Income taxes are accounted for using an asset and liability approach that requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities at the applicable tax rates, along with net operating loss and tax credit carryovers. The Company records a valuation allowance against its deferred tax assets to reduce the net carrying value to an amount that it believes is more likely than not to be realized. Management has considered estimated taxable income and ongoing prudent and feasible tax planning strategies in assessing the

amount of the valuation allowance. Based upon the weight of available evidence, which includes the Company’s historical operating performance and limited potential to utilize tax credit carryforwards, the Company has determined that total deferred tax assets should be fully offset by a valuation allowance. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.

The Company is required to file federal and state income tax returns in the United States and various other state jurisdictions. The Company also files income tax returns in the foreign countries in which it operates. The preparation of these income tax returns requires the Company to interpret the applicable tax laws and regulations in effect in such jurisdictions, which could affect the amount of tax paid by the Company.

Additionally, the Company follows an accounting standard addressing the accounting for uncertainty in income taxes that prescribes rules for recognition, measurement, and classification in the consolidated financial statements of tax positions taken or expected to be taken in a tax return.

Net Income (Loss) per Share

Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding for the period, without consideration for common stock equivalents. Diluted net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive shares of common stock for the year ended December 31, 2023 were comprised of stock options and restricted stock units. Dilutive shares of stock for the years ended December 31, 2022 and 2021 were comprised of stock options.

No dividends were declared or paid during the reporting periods.

Recently Issued Accounting Standards Not Yet Adopted

From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. The Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the consolidated financial statements and disclosures.

Insider Trading Arrangements	12 Months Ended
Insider Trading Arrangements	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Rule 10b5-1 Trading Plans For the year ended December 31, 2023, none of our directors or officers adopted or terminated a "Rule 10b5-1 trading arrangement" (as defined in Item 408 of Regulation S-K of the Exchange Act) intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act, other than as follows: • Dr. Padmanabh Chivukula, Chief Scientific Officer and Chief Operating Officer, cancelled an existing Rule 10b5-1trading arrangement on November 18, 2023. Dr. Chivukula's trading arrangement provided for the sale of up to an aggregate of 100,000 shares of common stock. Subsequent to this, Dr. Chivukula entered into a new Rule 10b5-1 trading arrangement on December 14, 2023. The new trading arrangement provides for the sale of up to an aggregate of 152,000 shares, until September 15, 2025. • Keith C. Kummerfeld, Senior Vice President, Corporate Controller and Principal Accounting Officer, modified an existing Rule 10b5-1trading arrangement on August 24, 2023. Mr. Kummerfeld's trading arrangement provides for the exercise of up to an aggregate of 36,064 options to purchase common stock and subsequent sale of such underlying shares of common stock, until August 23, 2024. On February 20, 2024, Mr. Kummerfeld, informed the Company that he will resign from his position, effective March 15, 2024, to pursue another opportunity. There were no "non-Rule 10b5-1 trading arrangements" (as defined in Item 408 of Regulation S-K of the Exchange Act) adopted or terminated during the year ended December 31, 2023 by our directors and officers.
Dr. Padmanabh Chivukula [Member]
Trading Arrangements, by Individual
Name	Dr. Padmanabh Chivukula
Title	Chief Scientific Officer and Chief Operating Officer
Adoption Date	December 14, 2023
Aggregate Available	152,000
Expiration Date	September 15, 2025
Keith C. Kummerfeld [Member]
Trading Arrangements, by Individual
Name	Keith C. Kummerfeld
Title	Senior Vice President, Corporate Controller and Principal Accounting Officer
Aggregate Available	36,064
Expiration Date	August 23, 2024
Directors or Officers Except Chief Scientific Officer, COO, SVP, CC and PAO [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Commitments and Contingencies (Details Textual) - USD ($) $ in Millions		1 Months Ended		12 Months Ended			50 Months Ended
	Aug. 01, 2019	Sep. 30, 2021	Oct. 31, 2017	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 25, 2023	Feb. 29, 2020
Commitment And Contingencies [Line Items]
Operating lease costs				$ 5.6	$ 4.7	$ 1.9
February 2020 Lease Agreement [Member]
Commitment And Contingencies [Line Items]
Operating lease extended additional term								13 months
Lessee, operating leases, option to extend				the lease for one twelve-month period. In February 2021, the Company opted to extend the lease through March 2025 to coincide with the lease term of the Company’s headquarters
September 2021 Lease Agreement [Member]
Commitment And Contingencies [Line Items]
Operating lease extended additional term		10 years 8 months
Lessee, operating leases, option to extend				the Company will have the right to extend the term of the lease for an additional five-year period
Security deposit		$ 2.0
Underlying Agreement [Member] \| Cystic Fibrosis Foundation [Member]
Commitment And Contingencies [Line Items]
Contra expense remaining amount included in accrued expenses				$ 7.6
Contra expense included in research and development expense				$ 1.4	$ 5.2	$ 3.8
Minimum amount agreed to incur under research plan							$ 15.0
Underlying Agreement [Member] \| LUNAR-CF [Member] \| Cystic Fibrosis Foundation [Member]
Commitment And Contingencies [Line Items]
Payments for advance	$ 15.6						$ 24.6
October 2017 Lease Amendment [Member]
Commitment And Contingencies [Line Items]
Operating lease extended additional term			84 months
Lessee, operating lease, term of contract			4 months
Tenant improvement allowance			$ 0.1
Lessee, operating leases, option to extend				The lease may be extended for one five-year period at the then current market rate with annual escalations
Security deposit			$ 0.1
Maximum [Member] \| September 2021 Lease Agreement [Member]
Commitment And Contingencies [Line Items]
Monthly base rent		0.4
Minimum [Member] \| September 2021 Lease Agreement [Member]
Commitment And Contingencies [Line Items]
Monthly base rent		$ 0.3

Revenue (Details Textual) - USD ($) shares in Thousands		1 Months Ended		12 Months Ended
Revenue (Details Textual) - USD ($) shares in Thousands	Nov. 01, 2022	Feb. 28, 2023	Aug. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue [Line Items]
Collaboration revenue				$ 166,799,000	$ 205,999,000	$ 12,359,000
Deferred revenue				$ 87,325,000	$ 48,719,000
Purchase of common stock, shares				26,828	26,555
Revenue recognized				$ (166,799,000)
Seqirus Inc [Member]
Revenue [Line Items]
Collaboration revenue				147,900,000
Upfront payment received				200,000,000
BARDA [Member]
Revenue [Line Items]
Revenue recognized				9,100,000	$ 200,000
Total grant revenue			$ 63,200,000
Grant revenue outstanding				54,100,000
ASC 606 [Member] \| Vinbiocare [Member]
Revenue [Line Items]
Deferred revenue				0
Remaining performance obligation				0
Foreign Countries [Member]
Revenue [Line Items]
Collaboration revenue				154,900,000	192,700,000	5,000,000
Research Collaboration And License Agreement [Member] \| Seqirus Inc [Member]
Revenue [Line Items]
Upfront payment received	$ 200,000,000
Research Collaboration And License Agreement [Member] \| Seqirus Inc [Member] \| COVID-19 Vaccine [Member]
Revenue [Line Items]
Development milestones received advance payment				5,300,000
Net profits percentage	40.00%
Research Collaboration And License Agreement [Member] \| Seqirus Inc [Member] \| Manufacturing and Supply of ARCT-154 Drug Product [Member]
Revenue [Line Items]
Development milestones received advance payment				23,600,000
Research Collaboration And License Agreement [Member] \| Maximum [Member] \| Seqirus Inc [Member]
Revenue [Line Items]
Eligible to receive development milestone payment	$ 1,300,000,000
Eligible to receive commercial milestone payment	$ 3,000,000,000
Vinbiocare Agreement [Member]
Revenue [Line Items]
Upfront payment received						$ 40,000,000
Reserved upfront payment				11,800,000
Additional financial support		$ 2,100,000
Vinbiocare Agreement [Member] \| ASC 606 [Member] \| Vinbiocare [Member]
Revenue [Line Items]
Deferred revenue					0
CSL Collaboration Agreement [Member]
Revenue [Line Items]
Development milestones achieved				154,200,000
Achieved development milestone included accounts receivable				23,800,000
Deferred revenue				87,100,000	$ 45,600,000
CSL Collaboration Agreement [Member] \| Phase I Clinical Study [Member]
Revenue [Line Items]
Deferred revenue				15,100,000
Milestone payments				17,500,000
Remaining performance obligation				2,400,000
CSL Collaboration Agreement [Member] \| Maximum [Member] \| Phase I Clinical Study [Member]
Revenue [Line Items]
Additional payments upon meeting certain clinical milestones				1,500,000
Study Support Agreement [Member] \| ASC 606 [Member] \| Vinbiocare [Member] \| Short-Term Contract with Customer [Member]
Revenue [Line Items]
Accrued liabilities paid upon occurrence of specified events				2,500,000
Study Support Agreement [Member] \| ASC 606 [Member] \| Vinbiocare [Member] \| Long-Term Contract with Customer [Member]
Revenue [Line Items]
Accrued liabilities paid upon occurrence of specified events				$ 500,000

Organization

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization

Note 1. Organization

Description of Business

Arcturus Therapeutics Holdings Inc. (the “Company” or "Arcturus") is a clinical messenger RNA medicines company focused on the development of infectious disease vaccines and significant opportunities within liver and respiratory rare diseases. The Company became a clinical stage company during 2020 when it announced that its Investigational New Drug (“IND”) application for ornithine transcarbamylase (“OTC”) deficiency and its Clinical Trial Application (“CTA”) for candidate LUNAR-COV19 were approved by applicable health authorities.

Recent Developments

See “Note 3 Revenue – CSL Seqirus” for further information on the agreement with Seqirus, Inc. ("CSL Seqirus"), whereby CSL Seqirus and the Company continue to collaborate on research and development, manufacturing and global commercialization of vaccines.

Liquidity

The Company has incurred significant operating losses since its inception. As of December 31, 2023 and 2022, the Company had an accumulated deficit of $367.9 million and $338.1 million, respectively.

The Company’s activities since inception have consisted principally of research and development activities, general and administrative activities, and raising capital. The Company’s activities are subject to significant risks and uncertainties, including failing to secure additional funding before the Company achieves sustainable revenues and profit from operations. From the Company’s inception through the year ended December 31, 2023, the Company has funded its operations principally with the proceeds from revenues earned through collaboration agreements, including the $200.0 million upfront payment received from CSL Seqirus during 2022, the sale of capital stock and proceeds from long-term debt. During fiscal year 2023, the Company received milestone payments totaling $147.9 million from CSL Seqirus. Additionally, the Company received milestone payments of $23.8 million from CSL Seqirus subsequent to December 31, 2023. At December 31, 2023, the Company’s balance of cash and cash equivalents, including restricted cash, was $348.9 million.

Management believes that it has sufficient working capital on hand to fund operations through at least the next twelve months from the date these consolidated financial statements were available to be issued. There can be no assurance that the Company will be successful in acquiring additional funding, that the Company’s projections of its future working capital needs will prove accurate, or that any additional funding would be sufficient to continue operations in future years.

Revenue

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Revenue

NOTE 3. Revenue

The Company has entered into license agreements and collaborative research and development arrangements with pharmaceutical and biotechnology companies, as well as consulting, related technology transfer and product revenue agreements. Under these arrangements, the Company is entitled to receive license fees, consulting fees, product fees, technological transfer fees, upfront payments, milestone payments if and when certain research and development milestones, technology transfer milestones or success-based milestones are achieved, royalties on approved product sales and reimbursement for research and development activities. The Company’s costs of performing these services are included within research and development expenses. The Company’s milestone payments are typically defined by achievement of certain preclinical, clinical, and commercial success criteria. Preclinical milestones may include in vivo proof of concept in disease animal models, lead candidate identification, and completion of IND-enabling toxicology studies. Clinical milestones may, for example, include successful enrollment of the first patient in or completion of Phase 1, 2 and 3 clinical trials, and commercial milestones are often tiered based on net or aggregate sale amounts. The Company cannot guarantee the achievement of these milestones due to risks associated with preclinical and clinical activities required for development of nucleic acid medicine-based therapeutics and vaccines.

The following table presents changes in the balances of receivables and contract liabilities related to strategic collaboration agreements during the year ended December 31, 2023:


(in thousands)	December 31, 2022		Additions		Deductions			December 31, 2023
Contract Assets:
Accounts receivable	$	2,764	$	205,746	$	(176,446	)	$	32,064
Contract Liabilities:
Deferred revenue	$	48,719	$	205,405	$	(166,799	)	$	87,325

The following table summarizes the Company’s revenue for the periods indicated. Approximately $154.9 million, $192.7 million and $5.0 million of total revenue represents revenue derived from foreign countries for the years ended December 31, 2023, 2022 and 2021, respectively.


	For the Year Ended December 31,
(in thousands)	2023		2022		2021
Collaboration revenue:
CSL Seqirus	$	154,264	$	154,425	$	—
Vinbiocare		—		24,571		4,364
Janssen		660		9,201		3,129
Ultragenyx		1,837		3,739		3,700
Israel Ministry of Health		—		12,500		—
Other		987		1,319		1,166
Total collaboration revenue	$	157,748	$	205,755	$	12,359
Grant revenue:
BARDA	$	9,051	$	244	$	—
Total grant revenue	$	9,051	$	244	$	—

The following paragraphs provide information regarding the nature and purpose of the Company’s most significant revenue arrangements.

CSL Seqirus

On November 1, 2022, the Company entered into a Collaboration and License Agreement (as amended, the “CSL Collaboration Agreement”) with Seqirus, Inc., a part of CSL Limited (“CSL Severus”), for the global exclusive rights to research, develop, manufacture, and commercialize vaccines. Under the terms of the CSL Collaboration Agreement, the Company provides CSL Seqirus with an exclusive global license to its mRNA technology (including STARR®) and LUNAR® lipid-mediated delivery, along with mRNA drug substance and drug product manufacturing process. CSL Seqirus will lead development and commercialization of vaccines under the collaboration. The collaboration plans to advance vaccines against SARS-CoV-2 (COVID-19), influenza, pandemic preparedness as well as three other respiratory infectious diseases.

The Company received a $200.0 million upfront payment and is eligible to receive over $1.3 billion in development milestones if all products are registered in the licensed fields and entitled to potentially receive up to $3.0 billion in commercial milestones based on “net sale” of vaccines in the various fields. In addition, the Company is eligible to receive a 40% net profit share for COVID-19 vaccine products and up to low double-digit royalties for vaccines against flu, pandemic preparedness and three other respiratory pathogens. During 2023, the Company achieved $154.2 million of development milestones and a conditional payment related to the CSL Collaboration Agreement, of which $23.8 million was included in accounts receivable as of December 31, 2023.

In evaluating the CSL Collaboration Agreement in accordance with Accounting Standards Codification (“ASC”) Topic 606, the Company concluded that CSL Seqirus is a customer. The Company identified all promised goods/services within the CSL Collaboration Agreement, and when combining certain promised goods/services, the Company concluded that there are five distinct performance obligations. The nature of the performance obligations consists of delivery of the vaccine license, research and development services for COVID and non-COVID vaccines and regulatory activities for COVID vaccines. For each performance obligation, the Company estimated the standalone selling price based on 1) in the case of the license, the fair value using costs to recreate plus margin method and 2) in the case of research and development services and regulatory activities, cost plus margin for estimated full-time equivalent (“FTE”) costs, direct costs including laboratory supplies, contractors, and other out-of-pocket expenses for research and development services and regulatory activities.

As of December 31, 2023, the transaction price consisted of upfront consideration received and milestones achieved in 2023. Additional variable consideration was not included in the transaction price at December 31, 2023 because the Company could not conclude that it is probable that including the variable consideration will not result in a significant revenue reversal.

The Company allocated the transaction price to the performance obligations in proportion to their standalone selling price. The vaccine license was recognized at the point in time it was transferred in 2022. The research and development and regulatory activities performance obligations are recognized over a period of time based on the percentage of services rendered using the input method, meaning actual costs incurred divided by total costs budgeted to satisfy the performance obligation. Any consideration related to sales-based royalties will be recognized when the amounts are probable of non-reversal, provided that the reported sales are reliably measurable and the Company has no remaining promised goods/services, as they are constrained and therefore have also been excluded from the transaction price. The revenue recognized in 2023 and 2022 relates to the license delivered, milestones achieved and services performed through December 31, 2023.

Total deferred revenue as of December 31, 2023 and 2022 for the CSL Collaboration Agreement was $87.1 million and $45.6 million, respectively.

During 2023, the Company also received an advance payment of $23.6 million for the manufacturing and supply of ARCT-154 drug product. The advance payment was for specified manufacturing runs of ARCT-154 which include the drug substance utilized, as well as the reservation fees and related manufacturing requirements. The Company concluded that the promise to manufacture and supply ARCT-154 drug product is a customer option as part of the CSL Collaboration Agreement and is accounted for as a separate contract. The advance payment is included in deferred revenue as of December 31, 2023 and will be recognized as revenue when the drug product is transferred to CSL Seqirus.

During 2023, the Company entered into an amendment to the CSL Collaboration Agreement, pursuant to which the Company agreed to sponsor and conduct a Phase I clinical study in the influenza field. As part of the amendment, the Company received $17.5 million from CSL Seqirus. The amendment also provides for up to $1.5 million in additional payments which are achievable upon meeting certain clinical milestones relating to the Phase I clinical study in the influenza field. The Company previously concluded that the expansion of research and development support services under the CSL Collaboration Agreement represented an option that was not a material right. Therefore the Company concluded the promise to sponsor and conduct the Phase I clinical study is a separate contract and the sole performance obligation under the new arrangement. During the year ended December 31, 2023, the Company recognized $2.4 million related to the performance obligation and the remaining amount of $15.1 million is included in deferred revenue.

In December 2023, the Company also received an advance payment of $5.3 million from CSL Seqirus for manufacturing activities related to COVID-19 vaccine product. The Company concluded that the promise to perform manufacturing activities is a customer option as part of the CSL Collaboration Agreement and is accounted for as a separate contract. The advance payment is included in deferred revenue as of December 31, 2023 and will be recognized as revenue when the vaccine product is transferred to CSL Seqirus.

Vinbiocare

During 2021 the Company entered into certain agreements with Vinbiocare, a member of Vingroup Joint Stock Company, whereby the Company would provide technical expertise and support services to Vinbiocare to assist in the build out of a mRNA drug product manufacturing facility in Vietnam. The Company received an upfront payment in aggregate of $40.0 million as part of the Vinbiocare Agreement. In October 2022, the Company and Vinbiocare executed a letter agreement terminating the Technology License and Technical Support Agreement and the Framework Drug Substance Supply Agreement (collectively, the “License & Supply Agreements”). The Company incurred no financial penalties in connection with the termination of the License & Supply Agreements and has no further financial obligations to Vinbiocare under these terminated agreements.

In October 2022, in association with the termination of the License & Supply Agreements, the Company signed the Study Support Agreement with Vinbiocare which provides that Vinbiocare shall continue to serve as the regulatory and financial sponsor of clinical studies conducted in Vietnam of ARCT-154 pursuant to the Company’s arrangements with Vinbiocare (the “Study Support Agreement”). To support the continuing activities of these studies, the Study Support Agreement further provides for the Company to conduct certain services and to compensate Vinbiocare to help achieve the objectives of these studies. In February 2023, the Company agreed to provide additional financial support in the amount of approximately $2.1 million to allow Vinbiocare to provide additional study support duties related to the ARCT-154 clinical study. As a result, the Company reserved $11.8 million of the original upfront payment to be paid to Vinbiocare over the future periods pursuant to the Study Support Agreement by reclassifying a portion of the upfront payment received from Vinbiocare pursuant to the

License & Supply Agreements, from deferred revenue to short-term and long-term liabilities, based on the anticipated timing of the payments to Vinbiocare, and removed that portion of the upfront payment from the transaction price of the modified arrangement. The transaction price was not adjusted for payments that are contingent upon the occurrence of future regulatory or sales-related events based on the information currently available to the Company.

The Company has concluded that it has no remaining performance obligations under its prior arrangements with Vinbiocare as summarized above as of December 31, 2023. As of December 31, 2023, the Company has accrued liabilities related to this arrangement of $2.5 million in current liabilities and $0.5 million in non-current liabilities that will be paid upon the occurrence of specified events through the first quarter of 2025. Vinbiocare is also eligible to receive a single digit percentage of amounts from net sales, if any, of ARCT-154 (or next-generation COVID vaccine) up to a capped amount of low single digit millions. The Company had no remaining deferred revenue as of December 31, 2023 or 2022.

BARDA Grant

In August 2022, the Company entered into a cost reimbursement contract with the Biomedical Advanced Research and Development Authority ("BARDA"), a division of the Office of the Assistant Secretary for Preparedness and Response (ASPR) within the U.S. Department of Health and Human Services (HHS) for an award of up to $63.2 million for the development of a pandemic influenza vaccine using the Company's STARR® self-amplifying mRNA vaccine platform technology. The Company earns grant revenue for performing tasks under the agreement.

The Company determined that the agreement with BARDA is not in the scope of ASC 808 or ASC 606. Applying International Accounting Standards No. 20 ("IAS 20"), Accounting for Government Grants and Disclosure of Government Assistance, by analogy, the Company recognizes grant revenue from the reimbursement of direct out-of-pocket expenses, overhead allocations and fringe benefits for research costs associated with the grant. The costs associated with these reimbursements are reflected as a component of research and development expense in the Company’s consolidated statements of operations and comprehensive income (loss).

The Company recognized $9.1 million and $0.2 million of grant revenue during the years ended December 31, 2023 and 2022, respectively. which is included in revenue on the Company's consolidated statements of operations. As of December 31, 2023, the remaining available funding net of revenue earned was $54.1 million.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Summary of Components of Property and Equipment, Net

Property and equipment, net consisted of the following:


	December 31,
(in thousands)	2023			2022
Research equipment	$	16,046		$	10,251
Computers and software		1,275			1,154
Office equipment and furniture		958			958
Leasehold improvements		2,655			2,491
Construction in progress		233			3,344
Total	$	21,167		$	18,198
Less accumulated depreciation and amortization		(8,740	)		(5,783	)
Property and equipment, net	$	12,427		$	12,415

Revenue - Summary of Changes in Balances of Receivables and Contract Liability (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Revenue from Contract with Customer [Abstract]
Accounts receivable, Balance	$ 2,764
Additions	205,746
Deductions.	(176,446)
Accounts receivable, Balance	32,064
Deferred revenue, Balance	48,719
Additions	205,405
Deductions	(166,799)
Deferred revenue, Balance	$ 87,325

Share-Based Compensation (Details) - Employee Stock Option - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life (in years)	6 years 14 days	6 years 18 days	6 years 10 days
Expected volatility	76.10%	82.10%	73.70%
Risk-free interest rate	3.91%	2.93%	1.13%
Grant date weighted average fair value	$ 18.87	$ 15.56	$ 26.71

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Share-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Share-Based Compensation

NOTE 9. Share-Based Compensation

In June 2022 at the Company’s 2022 Annual Meeting of Stockholders (the "2022 Annual Meeting"), the stockholders of the Company approved an amendment to the Company’s 2019 Omnibus Equity Incentive Plan (as

amended, the “2019 Plan”) which, among other things, increases the aggregate number of shares authorized for use in making awards to eligible persons under the 2019 Plan by 3,750,000 shares, for a total of up to 8,750,000 shares available for issuance. As of December 31, 2023, a total of 193,642 shares remain available for future issuance under the 2019 Plan, subject to the terms of the 2019 Plan.

In October 2021, the Company adopted the 2021 Inducement Equity Incentive Plan which covers the award of up to 1,000,000 shares of common stock (the “2021 Plan”) effective as of October 15, 2021. Approval of the Company’s stockholders will not be required as a condition to the effectiveness of the 2021 Plan for so long as the plan is in compliance with Nasdaq inducement plan rules. In April 2022, the compensation committee of the Company’s board of directors approved a proposal to reduce the total number of shares available for future issuance under the 2021 Plan to 130,000. As of December 31, 2023, a total of 119,952 shares remain available for future issuance under the 2021 Plan, subject to the terms of the 2021 Plan.

Share Options

The following table presents the weighted-average assumptions used in the Black-Scholes valuation model by the Company in calculating the fair value of stock options granted:


	For the Year Ended December 31,
	2023			2022			2021
Expected life (in years)		6.04			6.05			6.03
Expected volatility		76.1	%		82.1	%		73.7	%
Expected dividend yield		—	%		—	%		—	%
Risk-free interest rate		3.91	%		2.93	%		1.13	%
Grant date weighted average fair value	$	18.87		$	15.56		$	26.71

The following table summarizes the Company’s stock option activity for the year ended December 31, 2023:


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding – December 31, 2022		6,622,740		$	34.78	8.2 years	$	10,721
Granted		2,140,206		$	27.38
Exercised		(237,820	)	$	11.26
Forfeited/cancelled		(553,999	)	$	34.31
Outstanding – December 31, 2023		7,971,127		$	33.55	7.9 years	$	53,295
Exercisable – December 31, 2023		3,700,692		$	38.04	6.6 years	$	31,142
Exercisable and expected to vest – December 31, 2023		7,971,127		$	33.55	7.9 years	$	53,295

At December 31, 2023, the total unrecognized compensation cost of $78.8 million will be recognized over the weighted-average remaining service period of approximately 3.0 years. The fair value of the options vested during the years ended December 31, 2023 , 2022 and 2021 was $35.3 million, $39.2 million and $28.4 million, respectively. The total intrinsic value of options exercised during the years ended December 31, 2023, 2022 and 2021was $4.3 million, $1.6 million and $3.6 million, respectively.

In August 2023, the Company granted 18,786 restricted stock units to its board of directors, when the fair value of the Company's common stock was $34.92 per share. These restricted stock units will vest at the Company's 2024 annual stockholders' meeting.

Share-based compensation expenses included in the Company’s statements of operations and comprehensive income (loss) for the years ended December 31, 2023, 2022 and 2021 were:


	For the Year Ended December 31,
(in thousands)	2023		2022		2021
Research and development	$	14,950	$	14,081	$	14,101
General and administrative		19,699		16,530		14,814
Total	$	34,649	$	30,611	$	28,915

Share-Based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jun. 30, 2022	Apr. 30, 2022	Oct. 15, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost not yet recognized		$ 78.8
Weighted-average remaining service period		3 years
Fair value of options vested		$ 35.3	$ 39.2	$ 28.4
The total intrinsic value of options exercised		$ 4.3	$ 1.6	$ 3.6
Fair value of common stock	$ 34.92
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units granted	18,786
2019 Omnibus Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation number of shares authorized					3,750,000
2019 Omnibus Equity Incentive Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation number of shares authorized					8,750,000
2019 Omnibus Equity Incentive Plan [Member] \| Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		193,642
2021 Inducement Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reduction in number of common stock shares available for future issuance						130,000
2021 Inducement Equity Incentive Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available							1,000,000
2021 Inducement Equity Incentive Plan [Member] \| Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		119,952

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 292,005	$ 391,883
Restricted cash	55,000
Accounts receivable	32,064	2,764
Prepaid expenses and other current assets	7,521	8,686
Total current assets	386,590	403,333
Property and equipment, net	12,427	12,415
Operating lease right-of-use asset, net	28,500	32,545
Non-current restricted cash	1,885	2,094
Total assets	429,402	450,387
Current liabilities:
Accounts payable	5,279	7,449
Accrued liabilities	31,881	30,232
Current portion of long-term debt		60,655
Deferred revenue	44,829	28,648
Total current liabilities	81,989	126,984
Deferred revenue, net of current portion	42,496	20,071
Operating lease liability, net of current portion	25,907	30,216
Other non-current liabilities	497	2,804
Total liabilities	150,889	180,075
Stockholders’ equity:
Common stock: $0.001 par value; 60,000 shares authorized; issued and outstanding shares were 26,828 at December 31, 2023 and 26,555 at December 31, 2022	27	27
Additional paid-in capital	646,352	608,426
Accumulated deficit	(367,866)	(338,141)
Total stockholders’ equity	278,513	270,312
Total liabilities and stockholders’ equity	$ 429,402	$ 450,387

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

NOTE 10. Income Taxes

A reconciliation of (loss) income before income taxes for domestic and foreign locations is as follows:


	For the Year Ended December 31,
(In thousands)	2023			2022		2021
United States	$	(27,890	)	$	10,644	$	(203,674	)
Foreign		—			—		—
Total (loss) income before income taxes	$	(27,890	)	$	10,644	$	(203,674	)

A reconciliation of income tax expense for the years ended December 31, 2023, 2022 and 2021 is as follows:


	For the Year Ended December 31,
	2023		2022		2021
Current:
Federal	$	1,246	$	1,121	$	—
State		589		174		—
Foreign		—		—		—
Total current income tax expense	$	1,835	$	1,295	$	—

Deferred:
Federal	$	—	$	—	$	—
State		—		—		—
Foreign		—		—		—
Total deferred income tax expense		—		—		—
Total income tax expense	$	1,835	$	1,295	$	—

A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	For the Year Ended December 31,
	2023			2022			2021
Federal statutory income tax rate		21.0	%		21.0	%		21.0	%
State income taxes, net of federal benefit		1.9	%		7.2	%		6.2	%
Stock-based compensation		(2.5	%)		16.1	%		(0.4	%)
Officers compensation		(7.4	%)		21.8	%		(1.1	%)
Research and development credits		20.0	%		(40.3	%)		2.9	%
Uncertain tax positions		(2.4	%)		9.0	%		(0.4	%)
Change in tax rate		0.2	%		(12.6	%)		(1.7	%)
Change in valuation allowance		(36.5	%)		(9.4	%)		(26.7	%)
Other		(0.3	%)		(1.0	%)		0.2	%
Permanent differences		(0.7	%)		0.4	%		—	%
Provision for income taxes		(6.7	)%		12.2	%		(0.0	)%

The significant components of deferred income taxes are as follows:


	December 31,
(in thousands)	2023			2022
Deferred tax assets:
Net operating loss	$	19,147		$	47,866
Tax credits		10,723			10,460
Accrued liabilities		943			1,420
Deferred revenue		7,014			611
Inventory		15,961			9,016
Basis difference in equity investments		2,202			2,212
Depreciation and amortization		—			—
Capitalized R&D		41,971			19,938
Right-of-use lease liability		7,233			8,200
Share-based compensation		11,618			7,201
Total gross deferred tax assets		116,812			106,924
Deferred tax liabilities:
Depreciation and amortization		(1,184	)		(475	)
Right-of-use asset		(6,822	)		(7,826	)
Total gross deferred tax liabilities		(8,006	)		(8,301	)
Valuation allowance		(108,806	)		(98,623	)
Net deferred tax asset	$	—		$	—

In assessing the realization of the deferred tax assets, the Company considers whether it is more likely than not that some portion of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which temporary differences representing net future deductible amounts become deductible. Due to lack of available sources of taxable income, the Company recorded a full valuation allowance against its net deferred tax assets as sufficient uncertainty exists regarding the future realization of these assets. As of December 31, 2023 and 2022, the Company recorded a valuation allowance of $108.8 million and $98.6 million, respectively. The valuation allowance changed by $10.2 million and ($1.0) million for the years ended December 31, 2023 and 2022, respectively.

At December 31, 2023, the Company has federal and state net operating losses, or NOL, carryforwards of approximately $27.9 million and $193.7 million, respectively. The federal net operating loss carryover includes $27.9 million of net operating losses generated in 2018 and after which can be carried forward indefinitely. The Company's state net operating losses start to expire 2039.

At December 31, 2023, the Company has federal and state research and development credit carryforwards of approximately $6.3 million and $6.6 million, respectively. The federal credit carryforwards begin to expire in 2037, and the state credits carry forward indefinitely. Additionally, the Company has an Orphan Drug Credit of $2.3 million as of December 31, 2023 which will begin to expire in 2042 unless previously utilized.

Pursuant to Internal Revenue Code (IRC) Sections 382 and 383, annual use of the Company’s federal and California net operating loss and research and development credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. The Company has completed an IRC Section 382 analysis through December 31, 2023 regarding the limitation of net operating loss carryforwards and other tax attributes. The Company experienced ownership changes in 2018 and 2020; however, the Company estimates that all tax attributes can be utilized. There is a risk that additional ownership changes may occur in the future. If a change in ownership occurs, the NOL carryforwards and other tax attributes could be limited or restricted.

The company accounts for income taxes in accordance with ASC 740-10, Accounting for Uncertainty in Income Taxes. The impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain tax position will not be recognized if it has less than 50% likelihood of being sustained.

A reconciliation of unrecognized tax benefits is as follows (in millions):


	December 31,
	2023		2022
Beginning balance of unrecognized tax benefits	$	2.9	$	2.4
Settlement of prior period tax positions		—		—
Decrease for prior period tax positions		0.1		(0.5	)
Increase for current period tax positions		0.6		1.0
Ending balance of unrecognized tax benefits	$	3.6	$	2.9

Amounts in the summary rollforward would not impact the effective tax rate as the Company maintains a full valuation on its net deferred tax assets. The Company is subject to taxation and files income tax returns in the United States, various U.S. states and foreign jurisdictions. The Company’s tax years from 2014 to date are subject to examination by the U.S., and state taxing authorities due to the carryforward of unutilized net operating losses and research and development credits. The Company’s policy is to recognize interest expense and penalties related to income tax matters as income tax expense. There was no tax related interest or penalties recognized for the years ended December 31, 2023, 2022 and 2021.

The Company does not anticipate any material changes to its unrecognized tax benefits within the next twelve months.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Accrued Liabilities Detail (Tables)

12 Months Ended

Dec. 31, 2023

Accrued Liabilities, Current [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following:


	December 31,
(in thousands)	2023		2022
Accrued compensation	$	5,918	$	4,038
Cystic Fibrosis Foundation liability		7,633		—
Income tax payable		641		1,295
Current portion of operating lease liability		4,309		3,884
Clinical trial accruals		2,333		4,531
Vinbiocare contractual liabilities		2,514		7,468
Other accrued research and development expenses		8,533		9,016
Total	$	31,881	$	30,232

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities
Net Income (Loss)	$ (29,725)	$ 9,349	$ (203,674)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization	2,957	1,527	1,193
Share-based compensation expense	34,649	30,611	28,915
Acquired in-process research and development expense			5,000
Loss (gain) from equity-method investment		515	(515)
Gain on debt extinguishment	(33,953)
Foreign currency transaction loss (gain)	90	375	(577)
Other non-cash expenses	502	2,173	1,990
Changes in assets and liabilities:
Accounts receivable	(29,300)	603	(1,242)
Prepaid expenses and other current assets	1,165	(3,584)	(2,333)
Right-of-use assets	4,045	3,264	1,392
Accounts payable	(2,238)	(3,112)	(769)
Accrued liabilities	(588)	9,443	4,134
Deferred revenue	38,606	(14,694)	32,794
Lease liabilities	(4,309)	(4,477)	(1,351)
Net cash (used in) provided by operating activities	(18,099)	31,993	(135,043)
Investing activities
Acquisition of property and equipment	(2,901)	(7,726)	(3,406)
Net cash used in investing activities	(2,901)	(7,726)	(3,406)
Financing activities
Proceeds from debt	20,000		46,599
Proceeds from exercise of stock options	2,668	1,730	902
Proceeds from issuance of common stock under equity plans	609	411	515
Payments on debt obligations	(47,364)	(5,000)
Net cash (used in) provided by financing activities	(24,087)	(2,859)	48,016
Net (decrease) increase in cash, cash equivalents and restricted cash	(45,087)	21,408	(90,433)
Cash, cash equivalents and restricted cash, beginning of year	393,977	372,569	463,002
Cash, cash equivalents and restricted cash, end of year	348,890	393,977	372,569
Supplemental disclosure of cash flow information
Cash paid for interest	2,127	813	684
Non-cash investing activities
Right-of-use assets acquired through operating leases		30,191	1,828
Acquisition of in-process research and development through issuance of common stock			5,000
Purchase of property and equipment in accounts payable and accrued expenses	$ 68	$ 573	$ 53

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue:
Total revenue	$ 166,799	$ 205,999	$ 12,359
Operating expenses:
Research and development, net	192,133	147,751	173,760
General and administrative	52,871	46,071	41,451
Total operating expenses	245,004	193,822	215,211
(Loss) income from operations	(78,205)	12,177	(202,852)
(Loss) gain from equity-method investment		(515)	515
(Loss) gain from foreign currency	(229)	(598)	584
Finance income (expense), net	16,591	(420)	(1,921)
Gain on debt extinguishment	33,953
Net (loss) income before income taxes	(27,890)	10,644	(203,674)
Provision for income taxes	1,835	1,295
Net (loss) income	$ (29,725)	$ 9,349	$ (203,674)
(Loss) earnings per share:
Basic	$ (1.12)	$ 0.35	$ (7.74)
Diluted	$ (1.12)	$ 0.35	$ (7.74)
Weighted-average shares used in calculation of (loss) earnings per share:
Basic	26,628	26,445	26,317
Diluted	26,628	27,093	26,317
Comprehensive (loss) income:
Net (loss) income	$ (29,725)	$ 9,349	$ (203,674)
Comprehensive (loss) income	(29,725)	9,349	(203,674)
Collaboration Revenue [Member]
Revenue:
Total revenue	157,748	205,755	$ 12,359
Grant Revenue [Member]
Revenue:
Total revenue	$ 9,051	$ 244

Revenue - Summary of Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation Of Revenue [Line Items]
Total revenue	$ 166,799	$ 205,999	$ 12,359
Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	157,748	205,755	12,359
Grant Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	9,051	244
CSL Seqirus [Member] \| Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	154,264	154,425
Vinbiocare [Member] \| Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		24,571	4,364
Janssen [Member] \| Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	660	9,201	3,129
Ultragenyx [Member] \| Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,837	3,739	3,700
Israel Ministry of Health [Member] \| Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		12,500
Other [Member] \| Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	987	1,319	$ 1,166
BARDA [Member] \| Grant Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 9,051	$ 244

Subsequent Events

12 Months Ended

Dec. 31, 2023

Subsequent Events [Abstract]

Subsequent Events

Note 13. Subsequent Events

None.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 2. Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

Segment Information

Cash and Cash Equivalents

Cash equivalents are short-term highly liquid investments that are readily convertible to cash with original maturities of three months or less at the date of purchase.

Restricted cash

Fair Value Measurements

Accounts Receivable

Concentration of Credit Risk and Significant Customers

There were two customers that comprised 100% of the total accounts receivable balance at December 31, 2023 and 2022.

Joint Ventures, Equity Method Investments and Variable Interest Entities

Property and Equipment, net

Comprehensive Income/Loss

Revenue Recognition

See “Note 3, Revenue” for specific details surrounding the Company’s arrangements.

Leases

See “Note 11, Commitments and Contingencies” for specific details surrounding the Company’s leases.

Research and Development Costs, net

Pre-Launch Inventory

Share-Based Compensation

Statement of Cash Flows


	As of December 31,
(in thousands)	2023		2022		2021
Cash and cash equivalents	$	292,005	$	391,883	$	370,492
Restricted cash - current		55,000		—		—
Non-current Restricted cash		1,885		2,094		2,077
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$	348,890	$	393,977	$	372,569

Income Tax Expense

Net Income (Loss) per Share

No dividends were declared or paid during the reporting periods.

Recently Issued Accounting Standards Not Yet Adopted

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

NOTE 11. Commitments and Contingencies

Cystic Fibrosis Foundation Therapeutics Funding agreement

On September 25, 2023, the Company amended its Development Program Letter Agreement, dated May 16, 2017 and as amended July 13, 2018 and August 1, 2019, with the Cystic Fibrosis Foundation (“CFF”). Pursuant to the amendment, (i) CFF increased the amount it will award to advance LUNAR-CF to $24.6 million from approximately $15.6 million, (ii) the Company agreed to incur at least $15.0 million toward activities under the research plan. During the fourth quarter of 2023, the Company received the full payment from CFF related to the amendment. For the years ended December 31, 2023, 2022 and 2021, the Company recognized contra expense of $1.4 million, $5.2 million and $3.8 million, respectively. As of December 31, 2023, $7.6 million remained in accrued liabilities.

Leases

In October 2017, the Company entered into a non-cancellable operating lease agreement for office space adjacent to its previously occupied headquarters. The commencement of the lease began in March 2018 and the lease extends for approximately 84 months from the commencement date with a remaining lease term through March 2025. Monthly rental payments are due under the lease and there are escalating rent payments during the term of the lease. The Company is also responsible for its proportional share of operating expenses of the building and common areas. In conjunction with the new lease, the Company received free rent for four months and received a tenant improvement allowance of $0.1 million. The lease may be extended for one five-year period at the then current market rate with annual escalations; however, the Company deemed the extension option not reasonably certain to be exercised and therefore excluded the option from the lease terms. The Company entered into an irrevocable standby letter of credit with the landlord for a security deposit of $0.1 million upon executing the lease which is included (along with additional funds required to secure the letter of credit) in the balance of non-current restricted cash.

In February 2020, the Company entered into a second non-cancellable operating lease agreement for office space near its current headquarters. The lease extended for 13 months from the commencement date and included a right to extend the lease for one twelve-month period. In February 2021, the Company opted to extend the lease through March 2025 to coincide with the lease term of the Company’s headquarters.

In September 2021, the Company entered into a fourth non-cancellable lease agreement for office, research and development, engineering and laboratory space near its current headquarters and lease term commenced during the second quarter of 2022. The initial term of the lease will extend ten years and eight months from the date of possession, and the Company will have the right to extend the term of the lease for an additional five-year period. When the lease term was determined for the operating lease right-of-use assets and lease liabilities, the extension

option for the lease was not included. The lease has a monthly base rent ranging from $0.3 million to $0.4 million which escalates over the lease term. The Company received a free rent period of four months and also pays for various operating costs, including utilities and real property taxes. The Company entered into an irrevocable standby letter of credit with the landlord for a security deposit of $2.0 million upon executing the lease which is included (along with additional funds required to secure the letter of credit) in the balance of non-current restricted cash.

Operating lease right-of-use asset and liability on the consolidated balance sheets represent the present value of remaining lease payments over the remaining lease terms. The Company does not allocate lease payments to non-lease components; therefore, payments for common-area-maintenance and administrative services are not included in the operating lease right-of-use asset and liability. The Company uses its incremental borrowing rate to calculate the present value of the lease payments, as the implicit rate in the lease is not readily determinable.

As of December 31, 2023, the remaining payments of the operating lease liability were as follows:


(in thousands)	Remaining Lease Payments
2024	$	5,646
2025		4,019
2026		3,603
2027		3,711
Thereafter		19,572
Total remaining lease payments		36,551
Less: imputed interest		(6,335	)
Total operating lease liabilities	$	30,216
Weighted-average remaining lease term		8.2
Weighted-average discount rate		4.8	%

Operating lease costs consist of the fixed lease payments included in operating lease liability and are recorded on a straight-line basis over the lease terms. Operating lease costs were $5.6 million, $4.7 million and $1.9 million for the years ended December 31, 2023, 2022 and 2021, respectively.

Revenue (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Summary of Changes in Balances of Receivables and Contract Liability

The following table presents changes in the balances of receivables and contract liabilities related to strategic collaboration agreements during the year ended December 31, 2023:


(in thousands)	December 31, 2022		Additions		Deductions			December 31, 2023
Contract Assets:
Accounts receivable	$	2,764	$	205,746	$	(176,446	)	$	32,064
Contract Liabilities:
Deferred revenue	$	48,719	$	205,405	$	(166,799	)	$	87,325

Schedule of Revenue


	For the Year Ended December 31,
(in thousands)	2023		2022		2021
Collaboration revenue:
CSL Seqirus	$	154,264	$	154,425	$	—
Vinbiocare		—		24,571		4,364
Janssen		660		9,201		3,129
Ultragenyx		1,837		3,739		3,700
Israel Ministry of Health		—		12,500		—
Other		987		1,319		1,166
Total collaboration revenue	$	157,748	$	205,755	$	12,359
Grant revenue:
BARDA	$	9,051	$	244	$	—
Total grant revenue	$	9,051	$	244	$	—

Income Taxes (Details 1) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details 1) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (27,890)	$ 10,644	$ (203,674)
Total (loss) income before income taxes	$ (27,890)	$ 10,644	$ (203,674)

Stockholders' Equity

12 Months Ended

Dec. 31, 2023

Stockholders' Equity Note [Abstract]

Stockholders' Equity

NOTE 8. Stockholders’ Equity

Earnings Per Share

Potentially dilutive securities that were not included in the calculation of diluted net loss per share for the year ended December 31, 2023 as they were anti-dilutive totaled 0.8 million. Potentially dilutive securities that were not included in the calculation of diluted earnings per share for the year ended December 31, 2022 as they were anti-dilutive totaled 3.7 million. Potentially dilutive securities that were not included in the calculation of diluted net loss per share for the year ended December 31, 2021 as they were anti-dilutive totaled 1.3 million.

Alexion Pharmaceuticals License Agreement

On February 17, 2021, the Company entered into an exclusive license agreement with Alexion Pharmaceuticals, Inc. (“Alexion”) pursuant to which Alexion granted to the Company an exclusive, worldwide license to exploit certain specified Alexion patent applications. In accordance with the terms of the license agreement, and in exchange for the license, the Company issued 74,713 shares of its common stock to Alexion on February 19, 2021 valued at approximately $5.0 million. The number of shares issued under the agreement was calculated by dividing (i) five million dollars ($5.0 million) by (ii) the volume-weighted average price per share of the Company’s common stock on the Nasdaq Global Market for the thirty (30) trading days immediately preceding the Effective Date (rounded to the nearest whole share). The Company recorded the transaction as an asset purchase as management concluded that all of the value received was related to a single identifiable asset. Further, the Company concluded that there was no alternative future use for the asset and recorded a charge at the closing of the transaction for the full $5.0 million value assigned to the shares issued in connection with the license agreement. This non-cash charge was recorded as acquired in-process research and development expense in the statements of operations and comprehensive income (loss).

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
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-Section 50
-Paragraph 13
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Paragraph 14
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (i)
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Fair Value Measurements (Details Textual) $ in Millions	Dec. 31, 2023 USD ($)
Recurring [Member] \| Money Market Funds [Member] \| Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	$ 256.1

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Schedule of Cash and Cash Equivalents and Restricted Cash


	As of December 31,
(in thousands)	2023		2022		2021
Cash and cash equivalents	$	292,005	$	391,883	$	370,492
Restricted cash - current		55,000		—		—
Non-current Restricted cash		1,885		2,094		2,077
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$	348,890	$	393,977	$	372,569

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	26,828,000	26,555,000
Common stock, shares outstanding	26,828,000	26,555,000

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2023	Mar. 04, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	ARCT
Entity Registrant Name	ARCTURUS THERAPEUTICS HOLDINGS INC.
Entity Central Index Key	0001768224
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-38942
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	32-0595345
Entity Address, Address Line One	10628 Science Center Drive
Entity Address, Address Line Two	Suite 250
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	900-2660
Entity Common Stock, Shares Outstanding		26,915,243
Entity Public Float			$ 692.4
Document Transition Report	false
Document Annual Report	true
Documents incorporated by reference	Certain portions of the registrant’s definitive Proxy Statement for its 2024 Annual Meeting of Stockholders are incorporated by reference into Items 10, 11, 12, 13 and 14 of Part III of this Annual Report on Form 10-K.
Auditor Firm ID	42
Auditor Name	Ernst & Young, LLP
Auditor Location	San Diego, California

Property and Equipment, Net - Summary of Components of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 21,167	$ 18,198
Less accumulated depreciation and amortization	(8,740)	(5,783)
Property and equipment, net	12,427	12,415
Research equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	16,046	10,251
Computer and software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,275	1,154
Office equipment and furniture [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	958	958
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,655	2,491
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 233	$ 3,344

Accrued Liabilities Detail

12 Months Ended

Dec. 31, 2023

Accrued Liabilities, Current [Abstract]

Accrued Liabilities Detail

NOTE 5. Accrued Liabilities Detail

Accrued liabilities consisted of the following:


	December 31,
(in thousands)	2023		2022
Accrued compensation	$	5,918	$	4,038
Cystic Fibrosis Foundation liability		7,633		—
Income tax payable		641		1,295
Current portion of operating lease liability		4,309		3,884
Clinical trial accruals		2,333		4,531
Vinbiocare contractual liabilities		2,514		7,468
Other accrued research and development expenses		8,533		9,016
Total	$	31,881	$	30,232

Commitments and Contingencies - Payments of Operating Lease Liability (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 5,646
2025	4,019
2026	3,603
2027	3,711
Thereafter	19,572
Total remaining lease payments	36,551
Less: imputed interest	(6,335)
Total operating lease liabilities	$ 30,216
Weighted-average remaining lease term	8 years 2 months 12 days
Weighted-average discount rate	4.80%

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Summary of Reconciliation of (Loss) Income Before Income Taxes for Domestic and Foreign Locations

A reconciliation of (loss) income before income taxes for domestic and foreign locations is as follows:


	For the Year Ended December 31,
(In thousands)	2023			2022		2021
United States	$	(27,890	)	$	10,644	$	(203,674	)
Foreign		—			—		—
Total (loss) income before income taxes	$	(27,890	)	$	10,644	$	(203,674	)

Summary of Reconciliation of Income Tax Expense

A reconciliation of income tax expense for the years ended December 31, 2023, 2022 and 2021 is as follows:


	For the Year Ended December 31,
	2023		2022		2021
Current:
Federal	$	1,246	$	1,121	$	—
State		589		174		—
Foreign		—		—		—
Total current income tax expense	$	1,835	$	1,295	$	—

Deferred:
Federal	$	—	$	—	$	—
State		—		—		—
Foreign		—		—		—
Total deferred income tax expense		—		—		—
Total income tax expense	$	1,835	$	1,295	$	—

Reconciliation of Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate

A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	For the Year Ended December 31,
	2023			2022			2021
Federal statutory income tax rate		21.0	%		21.0	%		21.0	%
State income taxes, net of federal benefit		1.9	%		7.2	%		6.2	%
Stock-based compensation		(2.5	%)		16.1	%		(0.4	%)
Officers compensation		(7.4	%)		21.8	%		(1.1	%)
Research and development credits		20.0	%		(40.3	%)		2.9	%
Uncertain tax positions		(2.4	%)		9.0	%		(0.4	%)
Change in tax rate		0.2	%		(12.6	%)		(1.7	%)
Change in valuation allowance		(36.5	%)		(9.4	%)		(26.7	%)
Other		(0.3	%)		(1.0	%)		0.2	%
Permanent differences		(0.7	%)		0.4	%		—	%
Provision for income taxes		(6.7	)%		12.2	%		(0.0	)%

Significant Components of Deferred Income Taxes

The significant components of deferred income taxes are as follows:


	December 31,
(in thousands)	2023			2022
Deferred tax assets:
Net operating loss	$	19,147		$	47,866
Tax credits		10,723			10,460
Accrued liabilities		943			1,420
Deferred revenue		7,014			611
Inventory		15,961			9,016
Basis difference in equity investments		2,202			2,212
Depreciation and amortization		—			—
Capitalized R&D		41,971			19,938
Right-of-use lease liability		7,233			8,200
Share-based compensation		11,618			7,201
Total gross deferred tax assets		116,812			106,924
Deferred tax liabilities:
Depreciation and amortization		(1,184	)		(475	)
Right-of-use asset		(6,822	)		(7,826	)
Total gross deferred tax liabilities		(8,006	)		(8,301	)
Valuation allowance		(108,806	)		(98,623	)
Net deferred tax asset	$	—		$	—

Summary of Reconciliation of Unrecognized Tax Benefits

A reconciliation of unrecognized tax benefits is as follows (in millions):


	December 31,
	2023		2022
Beginning balance of unrecognized tax benefits	$	2.9	$	2.4
Settlement of prior period tax positions		—		—
Decrease for prior period tax positions		0.1		(0.5	)
Increase for current period tax positions		0.6		1.0
Ending balance of unrecognized tax benefits	$	3.6	$	2.9

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (29,725)	$ 9,349	$ (203,674)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 36: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

NOTE 4. Fair Value Measurements

The Company establishes the fair value of its assets and liabilities using the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Company established a fair value hierarchy based on the inputs used to measure fair value.

The three levels of the fair value hierarchy are as follows:

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

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly.

Level 3: Unobservable inputs in which little or no market data exists and are therefore determined using estimates and assumptions developed by the Company, which reflect those that a market participant would use.

The carrying value of cash, restricted cash, accounts receivable, accounts payable, accrued liabilities and the Singapore loan approximate their respective fair values due to their relative short maturities. The carrying amounts of long-term debt for the amount drawn on the Company’s debt facility approximates fair value as the interest rate is variable and reflects current market rates.

The Company's assets measured at fair value on a recurring basis consisted of money market funds. As of December 31, 2023, the Company's had money market funds with a fair value of $256.1 million, which were classified within Level 1 of the fair value hierarchy. The fair value of these financial instruments was measured based on quoted prices

- 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

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Weighted Average Assumptions Used in Black -Scholes Valuation Model

The following table presents the weighted-average assumptions used in the Black-Scholes valuation model by the Company in calculating the fair value of stock options granted:


	For the Year Ended December 31,
	2023			2022			2021
Expected life (in years)		6.04			6.05			6.03
Expected volatility		76.1	%		82.1	%		73.7	%
Expected dividend yield		—	%		—	%		—	%
Risk-free interest rate		3.91	%		2.93	%		1.13	%
Grant date weighted average fair value	$	18.87		$	15.56		$	26.71

Summary of Share Option Activity

The following table summarizes the Company’s stock option activity for the year ended December 31, 2023:


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding – December 31, 2022		6,622,740		$	34.78	8.2 years	$	10,721
Granted		2,140,206		$	27.38
Exercised		(237,820	)	$	11.26
Forfeited/cancelled		(553,999	)	$	34.31
Outstanding – December 31, 2023		7,971,127		$	33.55	7.9 years	$	53,295
Exercisable – December 31, 2023		3,700,692		$	38.04	6.6 years	$	31,142
Exercisable and expected to vest – December 31, 2023		7,971,127		$	33.55	7.9 years	$	53,295

Schedule of Share-based Compensation Expenses

Share-based compensation expenses included in the Company’s statements of operations and comprehensive income (loss) for the years ended December 31, 2023, 2022 and 2021 were:


	For the Year Ended December 31,
(in thousands)	2023		2022		2021
Research and development	$	14,950	$	14,081	$	14,101
General and administrative		19,699		16,530		14,814
Total	$	34,649	$	30,611	$	28,915

Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details 2) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current:
Federal	$ 1,246	$ 1,121
State	589	174
Total current income tax expense	1,835	1,295
Deferred:
Total income tax expense	$ 1,835	$ 1,295

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Payments of Operating Lease Liability

As of December 31, 2023, the remaining payments of the operating lease liability were as follows:


(in thousands)	Remaining Lease Payments
2024	$	5,646
2025		4,019
2026		3,603
2027		3,711
Thereafter		19,572
Total remaining lease payments		36,551
Less: imputed interest		(6,335	)
Total operating lease liabilities	$	30,216
Weighted-average remaining lease term		8.2
Weighted-average discount rate		4.8	%

Related Party Transactions

12 Months Ended

Dec. 31, 2023

Related Party Transactions

Note 12. Related Party Transactions

On December 13, 2022, Vallon Pharmaceuticals, Inc. (“Vallon”) entered into an agreement with GRI Bio, Inc. (“GRI Bio”) pursuant to which GRI Bio was to merge with a wholly-owned subsidiary of Vallon in an all-stock transaction. The transaction closed in April 2023 and the Company's executive resigned from the board of directors of Vallon. Following the closing of the merger, the combined company now operates under the name “GRI Bio, Inc.” and will focus on the development of GRI Bio’s pipeline and trade on the Nasdaq under the ticker symbol “GRI”. Following the closing of the merger, the Company holds 28,125 shares in GRI Bio, or approximately 1%. Upon the closing of the merger, the Company determined that it did not have the ability to exercise significant influence over operating and financial policies of GRI Bio. As such, the Company discontinued the equity method of accounting for its investment in GRI Bio.

See “Note 2, Joint Ventures, Equity Method Investments and Variable Interest Entities” for specific details surrounding the Company’s agreement with Axcelead to form the joint venture entity, ARCALIS, Inc.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
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-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Income Taxes (Details 3)	12 Months Ended
Income Taxes (Details 3)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	1.90%	7.20%	6.20%
Share-based compensation	(2.50%)	16.10%	(0.40%)
Officers compensation	(7.40%)	21.80%	(1.10%)
Research and development credits	20.00%	(40.30%)	2.90%
Uncertain tax position	(2.40%)	9.00%	(0.40%)
Change in tax rate	0.20%	(12.60%)	(1.70%)
Change in valuation allowance	(36.50%)	(9.40%)	(26.70%)
Other	(0.30%)	(1.00%)	0.20%
Permanent differences	(0.70%)	0.40%
Provision for income taxes	(6.70%)	12.20%	0.00%

Income Taxes (Details Textual) - USD ($)	12 Months Ended
Income Taxes (Details Textual) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2018
Income Taxes [Line Items]
Valuation allowance	$ 108,806,000	$ 98,623,000
Valuation allowance change	$ 10,200,000	1,000,000
Maximum percentage of likelihood of uncertain tax position recognized to be sustained	50.00%
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0	$ 0	$ 0
Unrecognized tax benefits impacting effective tax rate	$ 0
Net Operating Loss and Research and Development Credit Carryforwards Limitations On Cumulative Change In Ownership Minimum Percentage	50.00%
Net Operating Loss and Research and Development Credit Carryforwards Limitations on Cumulative Change In Ownership Period	3 years
Orphan Drug Credit [Member]
Income Taxes [Line Items]
Credit Carryforward Amount	$ 2,300,000
Credit Carryforward Expiration Year	2042
Federal [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards	$ 27,900,000			$ 27,900,000
Federal [Member] \| Research Tax Credit Carryforward [Member]
Income Taxes [Line Items]
Credit Carryforward Amount	$ 6,300,000
Credit Carryforward Expiration Year	2037
State [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards	$ 193,700,000
Operating Loss Carryforwards Expiration Year	2039
State [Member] \| Research Tax Credit Carryforward [Member]
Income Taxes [Line Items]
Credit Carryforward Amount	$ 6,600,000

Organization (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Organization (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Organization And Significant Accounting Policies [Line Items]
Accumulated deficit	$ 367,866	$ 338,141
Collaboration revenue	166,799	205,999	$ 12,359
Cash and cash equivalents, including restricted cash	348,890	$ 393,977	$ 372,569	$ 463,002
Seqirus Inc [Member]
Organization And Significant Accounting Policies [Line Items]
Upfront payment received	200,000
Collaboration revenue	147,900
Additional milestone payments received	$ 23,800

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1

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-Topic 606
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-Name Accounting Standards Codification
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-Paragraph 30
-Subparagraph (a)
-Publisher FASB
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-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

+ Details

Stockholders' Equity (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Feb. 19, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Non-cash charge recorded in acquired in-process research and development expense				$ 5,000
Antidilutive securities excluded from computation of earnings per share		800,000	3,700,000	1,300,000
Alexion [Member]
Class Of Stock [Line Items]
Issuance of common stock	74,713
Common stock issued, value	$ 5,000
Non-cash charge recorded in acquired in-process research and development expense				$ 5,000

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2023 USD ($) Customer Segment	Dec. 31, 2022 USD ($) Customer	Dec. 31, 2021 USD ($) Customer	Apr. 21, 2023 USD ($)
Summary Of Significant Accounting Policy [Line Items]
Number of operating segments for research and development \| Segment	1
Non-current restricted cash	$ 1,885,000	$ 2,094,000	$ 2,077,000
Allowance for Doubtful Accounts Receivable	0	0
Impairment losses	0	0	0
Other comprehensive loss	0	0	0
Income tax effect related to unrealized losses on marketable securities	0	0	$ 0
Dividends declared or paid	0	$ 0
Wells Fargo Credit Agreement [Member]
Summary Of Significant Accounting Policy [Line Items]
Debt instrument, collateral amount	$ 55,000,000			$ 55,000,000
Employees and Officers [Member]
Summary Of Significant Accounting Policy [Line Items]
Share options expiration period	10 years
Vesting period	4 years
Vesting description	Share-based compensation is recognized over the requisite service period of the individual awards using the straight-line attribution method, which generally equals the vesting period. Employees and officers’ stock options have a ten-year life and generally vest 25% on the first anniversary of the grant and in 1/36th equal installments on each monthly anniversary thereafter, such that options are fully vested on the four-year anniversary of the date of grant. The exercisability and vesting periods of options granted to consultants and directors vary.
First Year Anniversary of the Grant [Member] \| Employees and Officers [Member]
Summary Of Significant Accounting Policy [Line Items]
Vesting percentage	25.00%
Maximum [Member]
Summary Of Significant Accounting Policy [Line Items]
Property and equipment, useful lives	5 years
Minimum [Member]
Summary Of Significant Accounting Policy [Line Items]
Property and equipment, useful lives	3 years
Credit Risk [Member] \| Accounts Receivable [Member]
Summary Of Significant Accounting Policy [Line Items]
Number of customers \| Customer	2	2
Concentration risk, percentage	100.00%	100.00%
Customer Concentration Risk [Member] \| Revenue [Member]
Summary Of Significant Accounting Policy [Line Items]
Number of customers \| Customer	3	5	4
Customer Concentration Risk [Member] \| Revenue [Member] \| Top Three Customers [Member]
Summary Of Significant Accounting Policy [Line Items]
Concentration risk, percentage	99.00%
Customer Concentration Risk [Member] \| Revenue [Member] \| Top Five Customers [Member]
Summary Of Significant Accounting Policy [Line Items]
Concentration risk, percentage		99.00%
Customer Concentration Risk [Member] \| Revenue [Member] \| Top Four Customers [Member]
Summary Of Significant Accounting Policy [Line Items]
Concentration risk, percentage			99.00%

Income Taxes (Details 4) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss	$ 19,147	$ 47,866
Tax credits	10,723	10,460
Accrued liabilities	943	1,420
Deferred revenue	7,014	611
Inventory	15,961	9,016
Basis difference in equity investments	2,202	2,212
Capitalized R&D	41,971	19,938
Right-of-use lease liability	7,233	8,200
Share-based compensation	11,618	7,201
Total gross deferred tax assets	116,812	106,924
Deferred tax liabilities:
Depreciation and amortization	(1,184)	(475)
Right-of-use asset	(6,822)	(7,826)
Total gross deferred tax liabilities	(8,006)	(8,301)
Valuation allowance	$ (108,806)	$ (98,623)

Debt (Details Textual)			1 Months Ended		3 Months Ended	12 Months Ended
Debt (Details Textual)	Apr. 21, 2023 USD ($)	Mar. 14, 2023 USD ($)	Mar. 31, 2023 SGD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jan. 29, 2021 SGD ($)	Jan. 29, 2021 USD ($)	Nov. 07, 2020 SGD ($)
Western Alliance Bank [Member]
Debt Instrument [Line Items]
Interest expense related to long-term debt						$ 300,000	$ 900,000	$ 800,000
Loan and Security Agreement [Member] \| Western Alliance Bank [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Term loan		$ 15,000,000
Repayment of term loan		7,400,000
Repayament of principal and interest on collateralized term loan		$ 7,000,000
Loan maturity date		Oct. 30, 2023
Fee payable		$ 300,000
Loan and Security Agreement [Member] \| Western Alliance Bank [Member] \| Long-term Debt [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Interest of the prime rate plus		1.25%
Loan and Security Agreement [Member] \| Western Alliance Bank [Member] \| Long-term Debt [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Interest of the prime rate plus		2.75%
Wells Fargo Credit Agreement [Member]
Debt Instrument [Line Items]
Revolving credit line available	$ 50,000,000
Loans interest rate, percentage	2.00%
Term of agreement	2 years
Option for renewal term	1 year
Non-refundable commitment fee, percentage	0.25%
Long-term debt						0
Debt instrument, collateral amount	$ 55,000,000					55,000,000
Wells Fargo Credit Agreement [Member] \| SOFR [Member]
Debt Instrument [Line Items]
Loan accrues interest rate per annum, percentage	1.00%
Singapore Economic Development Board [Member]
Debt Instrument [Line Items]
Term loan											$ 62,100,000
Term loan draw down									$ 62,100,000	$ 46,600,000
Repayment of term loan			$ 22,800,000	$ 17,100,000
Loan accrues interest rate per annum, percentage											4.50%
Long-term debt							50,400,000
Remaining loan including accrued interest forgiveable					$ 34,000,000
Interest expense related to long-term debt						$ 500,000	$ 2,100,000	$ 1,900,000