| Summary of significant accounting policies (Policies) | 12 Months Ended |
| Dec. 31, 2023 |
| Accounting Policies [Abstract] | |
| Fiscal Year | Fiscal Year The Group’s fiscal year ends on December
31. |
| Principles of Consolidation | Principles of Consolidation The consolidated financial statements include
the accounts of SEALSQ Corp and its wholly owned subsidiaries over which the Group has control. Intercompany income and expenses, including unrealized
gross profits from internal group transactions and intercompany receivables, payables and loans, have been eliminated. |
| Use of Estimates | Use of Estimates The preparation of consolidated financial statements
in conformity with US GAAP requires management to make certain estimates, judgments and assumptions. We believe these estimates, judgements
and assumptions are reasonable, based upon information available at the time they were made. These estimates, judgments and assumptions
can affect the reported amounts of assets and liabilities as of the date of the financial statements as well as the reported amounts of
revenues and expenses during the periods presented. To the extent there are differences between these estimates, judgments or assumptions
and the actual results, our consolidated financial statements will be affected. In many cases, the accounting treatment of a particular
transaction is specifically dictated by US GAAP and does not require management’s judgment in its application. There are also areas
in which management’s judgment in selecting from available alternatives would not produce a materially different result. Our most critical accounting estimates include:
- Inventory Valuation (see Note 10)
- Recoverability of deferred tax assets (see Note 30)
- Revenue recognition (see Note 25)
- Bonds, mortgages and other long-term debt (see Note 19)
- Convertible note payable, noncurrent (see Note 19)
- Indebtedness to related parties (see Note 20) |
| Fair Value of Financial Instruments | Fair Value of Financial Instruments The Group’s financial instruments are primarily
composed of cash and cash equivalents, accounts receivable, accounts payable and other current liabilities, other liabilities, and debt obligations. Fair value is the price that would be received
to sell an asset or the amount paid to transfer a liability, also referred to as the “exit price,” in the principal or most
advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. In instances
in which the inputs used to measure fair value fall into different levels of the fair value hierarchy, as described in Note 6, the fair
value measurement classification is determined based on the lowest level input that is significant to the fair value measurement in its
entirety. Management’s assessment of the significance of a particular item to the fair value measurement in its entirety requires
judgment, including the consideration of inputs specific to the asset or liability. Fair values of financial instruments are estimated
using public market prices, quotes from financial institutions and other available information. Due to their short-term maturity, the
carrying amounts of cash and cash equivalents, accounts receivable and contract assets, accounts payable and other current liabilities
approximate their fair values, and management also believes that the carrying values of notes and other receivables and outstanding balances
on the Group’s credit and term loan facilities approximate their fair values, based on their specific asset and/or liability characteristics,
including having terms consistent with current market conditions. The fair value of convertible note payable is calculated based on the
present value of the future cash flows as of the reporting date. |
| Foreign Currency | Foreign Currency The functional currency of SEALSQ Corp is USD. In general, the functional currency of a foreign
operation is the local currency. Assets and liabilities recorded in foreign currencies are translated at the exchange rate on the balance
sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the year. The effects of foreign currency
translation adjustments are included in stockholders’ equity as a component of accumulated other comprehensive income / (loss).
The Group's reporting currency is USD. |
| Cash and Cash Equivalents | Cash and Cash Equivalents Cash consists of deposits held at major banks
that are readily available. Cash equivalents consist of highly liquid investments that are readily convertible to cash and with original
maturity dates of three months or less from the date of purchase. The carrying amounts approximate fair value due to the short maturities
of these instruments. |
| Accounts Receivable | Accounts Receivable Receivables represent rights to consideration
that are unconditional and consist of amounts billed and currently due from customers, and revenues that have been recognized for accounting
purposes but not yet billed to customers. The Group extends credit to customers in the normal course of business and in line with industry
practices. |
| Allowance for Credit losses | Allowance for Credit losses We recognize an allowance for credit losses to
present the net amount of receivables expected to be collected as of the balance sheet date. The allowance is based on the credit losses
expected to arise over the asset’s contractual term taking into account historical loss experience, customer-specific data as well
as forward-looking estimates. Expected credit losses are estimated individually. Accounts receivables are written off when deemed
uncollectible and are recognized as a deduction from the allowance for credit losses. Expected recoveries, which are not to exceed the
amount previously written off, are considered in determining the allowance balance at the balance sheet date. |
| Inventories | Inventories Inventories are stated at the lower of cost or
net realizable value. Costs are calculated using standard costs, approximating average costs. Finished goods and work-in-progress inventories
include material, labor and manufacturing overhead costs. The Group records an inventory valuation allowance based on an analysis of physical
deterioration, obsolescence or a comparison to the anticipated demand or market value based on a consideration of marketability and product
maturity, demand forecasts, historical trends and assumptions about future demand and market conditions. |
| Property, Plant and Equipment | Property, Plant and Equipment Property, Plant and Equipment Minimum Maximum Property, plant and equipment are stated at cost,
net of accumulated depreciation. Depreciation is computed using the straight-line method based on estimated useful lives which range from
1 5 |
| Intangible Assets | Intangible Assets Intangible Assets Those intangible assets that are considered to
have a finite useful life are amortized over their useful lives, which generally range from 1 10 |
| Leases | Leases In line with ASC 842, the Group, as a lessee,
recognizes right-of-use assets and related lease liabilities on its balance sheet for all arrangements with terms longer than twelve months,
and reviews its leases for classification between operating and finance leases. Obligations recorded under operating and finance leases
are identified separately on the balance sheet. Assets under finance leases and their accumulated amortization are disclosed separately
in the notes. Operating and finance lease assets and operating and finance lease liabilities are measured initially at an amount equal
to the present value of minimum lease payments during the lease term, as at the beginning of the lease term. The Group has elected the short-term lease practical
expedient whereby we do not present short-term leases on the consolidated balance sheet as these leases have a lease term of 12 months
or less at lease inception and do not contain purchase options or renewal terms that we are reasonably certain to exercise. We have also elected the practical expedients related
to lease classification of leases that commenced before the effective date of ASC 842. |
| Revenue Recognition | Revenue Recognition The Group’s policy is to recognize revenue
to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects
to be entitled in exchange for those goods or services. To achieve that core principle, the group applies the following steps:
- Step 1: Identify the contract(s) with a customer.
- Step 2: Identify the performance obligations in the contract.
- Step 3: Determine the transaction price.
- Step 4: Allocate the transaction price to the performance obligations in the contract.
- Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation Revenue is measured based on the consideration
specified in a contract with a customer and excludes amounts collected on behalf of third parties. We typically allocate the transaction
price to each performance obligation on the basis of the relative standalone selling prices of each distinct good or service promised
in the contract. If a standalone price is not observable, we use estimates. The Group recognizes revenue when it satisfies
a performance obligation by transferring control over goods or services to a customer. The transfer may be done at a point in time (typically
for goods) or over time (typically for services). The amount of revenue recognized is the amount allocated to the satisfied performance
obligation. For performance obligations satisfied over time, the revenue is recognized over time, most frequently on a prorata temporis If the Group determines that the performance obligation
is not satisfied, it will defer recognition of revenue until it is satisfied. We present revenue net of sales taxes and any
similar assessments. The Group delivers products and records revenue
pursuant to commercial agreements with its customers, generally in the form of an approved purchase order or sales contract. Where products are sold under warranty, the customer
is granted a right of return which, when exercised, may result in either a full or partial refund of any consideration received, or a
credit that can be applied against amounts owed, or that will be owed, to the Group. For any amount received or receivable for which we
do not expect to be entitled to because the customer has exercised its right of return, we recognize those amounts as a refund liability. |
| Contract Assets | Contract Assets Contract assets consist of accrued revenue where
the Group has fulfilled its performance obligation towards the customer but the corresponding invoice has not yet been issued. Upon invoicing,
the asset is reclassified to trade accounts receivable until payment. |
| Deferred Revenue | Deferred Revenue Deferred revenue consists of amounts that have
been invoiced and paid but have not been recognized as revenue. Deferred revenue that will be realized during the succeeding 12-month
period is recorded as current and the remaining deferred revenue recorded as non current. This would relate to multi-year certificates
or licenses. |
| Contract Liability | Contract Liability Contract liability consists of either:
- amounts that have been invoiced and not yet paid, nor recognized as revenue. Upon payment, the liability
is reclassified to deferred revenue if the amounts still have not been recognized as revenue. Contract liability that will be realized
during the succeeding 12-month period is recorded as current and the remaining contract liability recorded as non-current. This would
relate to multi-year certificates or licenses.
- advances from customers not supported by invoices. |
| Sales Commissions | Sales Commissions Sales commission expenses where revenue is recognized
are recorded in the period of revenue recognition. |
| Cost of Sales and Depreciation of Production Assets | Cost of Sales and Depreciation of Production
Assets Our cost of sales consists primarily of expenses
associated with the delivery and distribution of products. These include expenses related to the license to the Global Cryptographic ROOT
Key, the global Certification authorities as well as the digital certificates for people, servers and objects, expenses related to the
preparation of our secure elements and the technical support provided on the Group's ongoing production and on the ramp-up phase, including
materials, labor, test and assembly suppliers, and subcontractors, freights costs, as well as the amortization of probes, wafers and other
items that are used in the production process. This amortization is disclosed separately under depreciation of production assets on the
face of the income statement. |
| Research and Development and Software Development Costs | Research and Development and Software Development
Costs All research and development costs and software
development costs are expensed as incurred. |
| Advertising Costs | Advertising Costs All advertising costs are expensed as incurred. |
| Pension Plan | Pension Plan In the year 2023, the Group maintained
one defined benefit post-retirement plans covering the French employees of SEALSQ France SAS. In accordance with ASC 715-30, Defined Benefit
Plans – Pension, |
| Stock-Based Compensation | Stock-Based Compensation Stock-based compensation costs are recognized
in earnings using the fair-value based method for all awards granted. Fair values of options and awards granted are estimated using a
Black-Scholes option pricing model. The model’s input assumptions are determined based on available internal and external data sources.
The risk-free rate used in the model is based on the Swiss treasury rate for the expected contractual term. Expected volatility is based
on historical volatility of SEALSQ Shares. Compensation costs for unvested stock options
and awards are recognized in earnings over the requisite service period based on the fair value of those options and awards at the grant
date. Nonemployee share-based payment transactions are
measured by estimating the fair value of the equity instruments that an entity is obligated to issue and the measurement date will be
consistent with the measurement date for employee share-based payment awards (i.e., grant date for equity-classified awards). |
| Litigation and Contingencies | Litigation and Contingencies Should legal proceedings and tax matters arise,
due to their nature, such legal proceedings and tax matters involve inherent uncertainties including, but not limited to, court rulings,
negotiations between affected parties and governmental actions. Management assesses the probability of loss for such contingencies and
accrues liability and/or discloses the relevant circumstances, as appropriate. |
| Income Taxes | Income Taxes Taxes on income are accrued in the same period
as the income and expenses to which they relate . Deferred taxes are calculated on the temporary
differences that arise between the tax base of an asset or liability and its carrying value in the balance sheet of our companies prepared
for consolidation purposes, with the exception of temporary differences arising on investments in foreign subsidiaries where the Group
has plans to permanently reinvest profits into the foreign subsidiaries. Deferred tax assets on tax loss carry-forwards
are only recognized to the extent that it is “more likely than not” that future profits will be available and the tax loss
carry-forward can be utilized. Changes to tax laws or tax rates enacted at the
balance sheet date are taken into account in the determination of the applicable tax rate provided that they are likely to be applicable
in the period when the deferred tax assets or tax liabilities are realized. The Group is required to pay income taxes in a
number of countries. The Group recognizes the benefit of uncertain tax positions in the financial statements when it is more likely than
not that the position will be sustained on examination by the tax authorities. The benefit recognized is the largest amount of tax benefit
that is greater than 50 percent likely of being realized on settlement with the tax authority, assuming full knowledge of the position
and all relevant facts. The Group adjusts its recognition of these uncertain tax benefits in the period in which new information is available
impacting either the recognition or measurement of its uncertain tax positions. |
| Government Assistance - Research Tax Credits | Government Assistance - Research Tax Credits Research tax credits are provided
by the French government to give incentives for companies to perform technical and scientific research. SEALSQ France SAS is eligible
to receive such tax credits. These research tax credits are presented as a
reduction of research & development expenses in the income statement when companies that have qualifying expenses can receive such
grants in the form of a tax credit irrespective of taxes ever paid or ever to be paid, the corresponding research and development efforts
have been completed and the supporting documentation is available. The credit is deductible from the entity’s income tax charge
for the year or payable in cash the following year, whichever event occurs first. The tax credit is therefore considered to be a refundable
R&D tax credit which is s not within the scope of the income tax standard (ASC 740). It is included in current assets under government
assistance in the balance sheet in line with ASC 832. |
| Earnings per Share | Earnings per Share Basic earnings per share are calculated using
the two-class method required for companies with multiple classes of common stock. The two-class method determines net earnings per common
share for each class of common stock according to dividends declared or accumulated and participation rights in distributed and undistributed
earnings or losses. The two-class method requires income available to common stockholders for the period to be allocated between each
class of common stock based upon their respective rights to receive dividends as if all income for the period had been distributed. For SEALSQ, the dividend rights of the holders
of ordinary shares and F shares (collectively, the “ common stock When the effects are not antidilutive, diluted
earnings per share is calculated using the weighted-average outstanding common shares and the dilutive effect of stock options as determined
under the treasury stock method. |
| Segment Reporting | Segment Reporting Our chief operating decision maker, who is also
our Chief Executive Officer, regularly reviews information related to one operating segment, secure microcontrollers, for purposes of
allocating resources and assessing budgets and performance. We report our financial performance based on this segment structure in Note
31 . |
| Comprehensive Income / (Loss) | Comprehensive Income / (Loss) Comprehensive income includes net income and other
comprehensive income ("OCI"). Other comprehensive income consists of revenues, expenses, gains, and losses to be included in
comprehensive income but excluded from net income as listed in ASC 220-10-45-10A. In line with ASC 220 (Income Statement - Reporting
Comprehensive Income), we have elected to report comprehensive income in a single continuous financial statement with two sections: net
income and other comprehensive income. We present each of the components of other comprehensive
income separately, based on their nature, in the statement of comprehensive income. |
| Recent Accounting Pronouncements | Recent Accounting Pronouncements Adoption of new FASB Accounting Standard in
the current year – Prior-Year Financial Statements not restated: As of January 1, 2023, the Group adopted Accounting
Standards Update (ASU) 2021-08, Business Combinations (topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts
with Customers. ASU 2021-08 amends ASC 805 to “require
acquiring entities to apply Topic 606 to recognize and measure contract assets and contract liabilities in a business combination.”
Under current GAAP, an acquirer generally recognizes such items at fair value on the acquisition date. ASU 2021-08 requires contract assets
and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance
with ASC 606 (meaning the acquirer should assume it has entered the original contract at the same date and using the same terms as the
acquiree). This new ASU applies to contract assets and contract liabilities acquired in a business combination and to other contracts
that directly/indirectly apply the requirements of ASC 606. There was no impact on the Group's results upon
adoption of the standard. The group also adopted Accounting Standards Update
(ASU) 2022-02, Financial instruments – Credit Losses (Topic 326) Troubled Debt Restructuring and Vintage Disclosures. ASU 2022-02 eliminates troubled debt restructuring
guidance for organizations that adopted the amendments in ASU 2016-13 while providing for additional disclosures for loan modifications.
It eliminates guidance for troubled debt restructuring by creditors. In addition to the elimination of TDR guidance, an entity that has
adopted ASU 2022-02 no longer considers renewals, modifications, and extensions that result from reasonably expected TDRs in their calculation
of the allowance for credit losses in accordance with ASC 326-20. Additionally, ASU 2022-02 enhances disclosure requirements for certain
loan modifications by creditors for borrowers experiencing financial difficulty. ASU 2022-02 also amends the vintage disclosure guidance
for public business entities. There was no impact on the Group's results upon
adoption of the standard. New FASB Accounting Standard to be adopted
in the future: In March 2023, The FASB issued ASU No. 2023-01, Leases
(Topic 842): Common Control Arrangements, which requires all companies to amortize leasehold improvements associated with common
control leases over the asset’s useful life to the common control group regardless of the lease term. Summary: The amendments allow a private company to
elect to account for a common control leasing arrangement using the written terms and conditions without having to determine if those
terms and conditions are legally enforceable. If the terms of the arrangement are not in writing, then the entity would apply existing
guidance to determine the legally enforceable terms and conditions of the arrangement. The amendments also require leasehold improvements
associated with leases between entities under common control to be amortized over the useful life of the improvements until the lessee
ceases to control the use of the underlying asset through a lease, at which time the remaining value of the leasehold improvement would
be accounted for as a transfer between entities under common control. Effective Date: ASU 2023-01 is effective for public
business entities for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. An entity should
apply the amendments prospectively to business combinations occurring on or after the effective dates. Early adoption is permitted. The Group expects to adopt all the aforementioned
guidance when effective. Management is assessing the impact of the aforementioned guidance on its consolidated financial statements but
does not expect it to have a material impact. In October 2023, the FASB issued ASU No 2023-06,
Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative, which
amends the disclosure or presentation requirements related to various subtopics in the FASB Accounting Standards Codification (the “Codification”). Summary: Effective Date: ASU 2023-06 effective date for
entities subject to SEC disclosure requirements will be the same as the SEC’s effective date to remove the related disclosure from
Regulation S-X and Regulation S-K. Each amendment will be effective for all other entities two years later. Entities must adopt all amendments
prospectively, and early adoption is prohibited. If by June 30, 2027, the SEC has not removed the existing disclosure requirement from
Regulations S-X or S-K, the corresponding disclosure pending requirement will be removed from the Codification and will not become effective. The Group expects to adopt all the aforementioned
guidance when effective. Management is assessing the impact of the aforementioned guidance on its consolidated financial statements but
does not expect it to have a material impact. In November 2023, the FASB issued ASU No 2023-07,
Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances current segment disclosures and requires
additional disclosures of significant segment expenses. Summary: The amendments improve reportable segment
disclosure requirements, primarily through enhanced disclosures about significant segment expenses. In addition, the amendments enhance
interim disclosure requirements, clarify circumstances in which an entity can disclose multiple segment measures of profit or loss, provide
new segment disclosure requirements for entities with a single reportable segment, and contain other disclosure requirements. Effective Date: ASU 2023-07 is effective for public
business entities for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December
15, 2024. Early adoption is permitted. The Group expects to adopt all the aforementioned
guidance when effective. Management is assessing the impact of the aforementioned guidance on its consolidated financial statements but
does not expect it to have a material impact. In December 2023, the FASB issued ASU 2023-09,
Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which establishes new income tax disclosure requirements in addition
to modifying and eliminating certain existing requirements. Summary: The intent of this standard is to
enhance the decision usefulness of income tax disclosures. The standard applies to all entities subject to ASC Topic 740, Income Taxes.
In addition, entities will be required to disclose the amount of income taxes paid (net of refunds received) disaggregated by federal,
state, and foreign taxes. They will also disclose the amount of income taxes paid (net of refunds) disaggregated by individual jurisdictions
in which income taxes paid is equal to or greater than five percent of total income taxes paid. The standard also outlines additional
disclosure requirements for all entities and specific updates for public business entities. Effective Date: ASU 2023-09 is effective for public
business entities for fiscal years beginning after December 15, 2024. Early adoption is permitted. The Group expects to adopt all the aforementioned
guidance when effective. Management is assessing the impact of the aforementioned guidance on its consolidated financial statements but
does not expect it to have a material impact. |
