Note 1 - Description of Business and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2025

Notes to Financial Statements

Basis of Presentation and Significant Accounting Policies [Text Block]

1. DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Description of Business

PDF Solutions, Inc. (the “Company” or “PDF”), provides products and services designed to empower organizations across the semiconductor and electronics ecosystem to connect, collect, manage, and analyze data about design, equipment, manufacturing, and test to improve the yield and quality of their products and operational efficiency. The Company’s products, services, and solutions include proprietary software, physical intellectual property (“IP”) for integrated circuit (“IC”) designs, electrical measurement hardware tools, proven methodologies, and professional services.

Basis of Presentation

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries after the elimination of all significant intercompany balances and transactions.

Reclassification

Certain immaterial prior period amounts have been reclassified to conform with current period presentation with no effect on previously reported total assets, total liabilities, stockholders' equity or net income.

Change in Presentation of Revenues

As the Company’s business has evolved to include revenue from a broader portfolio of products and services, as a result of organic and inorganic expansion, beginning with this Annual Report on Form 10-K, the Company updated its presentation of revenue categories. Previously, the Company presented revenue in two categories: Analytics and Integrated Yield Ramp. Analytics revenue was derived from the following offerings: licenses and services for on-premise software, software-as-a-service (“SaaS”), licenses and purchase contracts for DirectScan™ systems (formerly known as “DFI systems”), and Characterization Vehicle® systems that did not include performance incentives based on customers’ yield achievement. Integrated Yield Ramp revenue was comprised of all fees from the Company’s contracts that included any performance incentives based on customers’ yield achievement. The Company now presents revenue in the following categories: Platform and Volume-based. Platform revenue is derived from the Company's following offerings: licenses for software (other than Cimetrix® runtime licenses) and related software maintenance and technical support services; SaaS; engineering services; fixed fees associated with CV® systems; and licenses and purchase contracts for DirectScan systems. Volume-based revenue is derived from Cimetrix runtime licenses, secureWISE® data, and Gainshare. See Note 2, “Revenue from Contracts with Customers.”

The change in presentation of revenues does not change the Company’s total revenues or total costs of revenues. The following table presents reclassified historical amounts to conform to the current period’s presentation (in thousands):

	Year Ended December 31,
	2024							2023
	Previously Reported		Change in Presentation Reclassification			Current Presentation		Previously Reported		Change in Presentation Reclassification			Current Presentation
Revenues:
Analytics	$	169,253	$	(169,253	)	$	—	$	152,085	$	(152,085	)	$	—
Integrated Yield Ramp		10,212		(10,212	)		—		13,750		(13,750	)		—
Platform		N/A		157,166			157,166		N/A		147,509			147,509
Volume-based		N/A		22,299			22,299		N/A		18,326			18,326
	$	179,465	$	—		$	179,465	$	165,835	$	—		$	165,835

Use of Estimates

The preparation of consolidated financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these consolidated financial statements include revenue recognition, the estimated useful lives of property and equipment and intangible assets, assumptions made in analysis of allowance for credit losses, fair values of assets acquired and liabilities assumed in business combinations, impairment of goodwill and long-lived assets, valuation for deferred tax assets, and accounting for lease obligations, stock-based compensation expense, and income tax uncertainties and contingencies. From time to time, the Company may enter into contingent fee arrangements with external legal firms that may represent the Company in legal proceedings related to disputes. The Company’s policy is to accrue contingent legal fees when they are probable and reasonably estimable. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position.

Concentration of Credit Risk

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, and accounts receivable. As of December 31, 2025 and 2024, and periodically throughout the year, the Company had cash balances in various operating accounts in excess of federally insured limits. The Company maintains its cash and cash equivalents with what it considers high credit quality financial institutions.

The Company primarily sells its products and services to companies in Asia, Europe, and North America within the semiconductor industry. As of December 31, 2025, two customers accounted for 64% of the Company’s gross accounts receivable and three customers accounted for 53% of the Company’s total revenues for 2025. As of December 31, 2024, four customers accounted for 57% of the Company’s gross accounts receivable and two customers accounted for 31% of the Company’s total revenues for 2024. One customer accounted for 35% of the Company’s revenues for 2023. See Note 13, “Customer and Geographic Information” for further details. The Company does not require collateral or other security to support accounts receivable. To reduce credit risk, management performs ongoing credit evaluations of its customers’ financial condition. The Company maintains allowances for potential credit losses.

The allowance for credit losses, which was based on management’s best estimates, could be adjusted in the near term from current estimates depending on actual experience. Such adjustments could be material to the consolidated financial statements.

Supplier Concentration

Some of the Company’s vendors provide highly specialized, differentiated products and services related to the Company’s DirectScan system and some licensors provide key enabling software for the Company’s products and services. In the event any of these suppliers delay or discontinue providing such products and services to the Company, it may be difficult for the Company to replace such suppliers, software, or parts in a timely manner or at all, which could delay or make impossible the Company’s ability to deliver or adequately support its software systems or to complete and deliver its DirectScan systems to its customers, and could negatively impact the Company’s future financial results of operations.

Cash, Cash Equivalents, and Investments

The Company considers all highly liquid investments with effective maturities of 90 days or less on the date of purchase to be cash equivalents. Investments with effective maturities greater than 90 days but less than one year are considered short-term investments, while investments with effective maturities greater than one year are considered long-term investments. The Company classifies its securities as available-for-sale investments and are carried at estimated fair value, with the unrealized gains and unrealized non-credit-related losses, net of tax, reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Unrealized credit-related losses are recorded to interest income and other, net in the Consolidated Statements of Operations and Comprehensive Income (Loss) with a corresponding allowance for credit-related losses in the Consolidated Balance Sheets. Realized gains and losses are based on the specific identification method and are included as a component of interest income and other, net in the Consolidated Statements of Operations and Comprehensive Income (Loss).

The Company periodically reviews its investments for impairment. For investments in unrealized loss positions, the Company assesses whether any portion of the decline in fair value below the amortized cost basis is due to credit-related factors if the Company neither intends to sell nor anticipates that it is more likely than not that it will be required to sell prior to recovery of the amortized cost basis. The Company considers factors such as the extent to which the market value has been less than the amortized cost basis, any noted failure of the issuer to make scheduled interest or principal payments, changes to the rating of the security by a rating agency and other relevant credit-related factors in determining whether or not a credit loss exists. There was no allowance for credit-related losses on any of the Company’s investments recognized during the years ended December 31, 2025 and 2024.

Short-term investments consisted solely of U.S. Government securities and other current investments consisted of a non-marketable convertible promissory note. The cost of these securities approximated fair value and there was no material gross realized or unrealized gains or losses as of December 31, 2025 and 2024. See Note 14, “Fair Value Measurements” for further discussion on the Company’s investments.

The Company recorded interest income from its cash, cash equivalents, and short-term investments of $1.5 million, $5.6 million and $5.5 million for the years ended December 31, 2025, 2024 and 2023, respectively.

Accounts Receivable

Accounts receivable includes amounts that are unbilled at the end of the period that are expected to be billed and collected within a 12‑month period. Unbilled accounts receivable are determined on an individual contract basis. Unbilled accounts receivable, included in accounts receivable, totaled $44.8 million and $23.0 million as of December 31, 2025 and 2024, respectively. Unbilled accounts receivable that are not expected to be billed and collected during the succeeding 12‑month period are recorded in other non-current assets and totaled $8.7 million and $9.0 million as of December 31, 2025 and 2024, respectively.

The Company performs ongoing credit evaluations of its customers’ financial condition. An allowance for credit losses is maintained for probable credit losses based upon the Company’s assessment of the expected collectibility of the accounts receivable. The allowance for credit losses is reviewed on a quarterly basis to assess the adequacy of the allowance.

The changes in allowance for credit losses are summarized below (in thousands):

					Deductions/
	Balance at				Write-offs			Balance at
	Beginning		Charged to		of Accounts			End of
	of Year		Expense (1)		Receivable			Year
2025	$	890	$	168	$	(168	)	$	890
2024	$	890	$	—		—		$	890
2023	$	890	$	20	$	(20	)	$	890

(1) Additions to the accounts receivable reserve for credit losses are charged to bad debt expense.

Property and Equipment

Property and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives (in years) of the related asset as follows:

Computer equipment	3
Software and capitalized software development cost	3-5
Furniture, fixtures, and equipment	5-10
Laboratory and test equipment	3-10
Leasehold improvements	Shorter of estimated useful life or term of lease

Intangible Assets

Intangible assets consist of acquired technology, certain contract rights, customer relationships, patents, trademarks and trade names. These intangible assets may be acquired through business combinations or direct purchases. Intangible assets are amortized on a straight-line basis over their estimated useful lives which range from one to ten years. The Company continually monitors events and changes in circumstances that could indicate carrying amounts of long-lived assets, including property and equipment and intangible assets, may not be recoverable. When such events or changes in circumstances occur, the Company assesses the recoverability of long-lived assets. Recoverability of an asset group is measured by comparison of its carrying amount to the expected future undiscounted cash flows that the asset group is expected to generate. If it is determined that an asset group is not recoverable, an impairment loss is recorded in the amount by which the carrying amount of the asset group exceeds its fair value.

Goodwill

The Company records goodwill when the purchase consideration of an acquisition exceeds the fair value of the net tangible and identified intangible assets as of the date of acquisition. The Company has one operating segment and one operating unit. The Company performs a qualitative analysis when testing a reporting unit’s goodwill for impairment. The Company performs an annual impairment assessment of goodwill during the fourth quarter of each calendar year or more frequently, if required to determine if any events or circumstances exist, such as an adverse change in business climate or a decline in the overall industry demand, that would indicate that it would more likely than not reduce the fair value of a reporting unit below its carrying amount, including goodwill. If events or circumstances do not indicate that the fair value of a reporting unit is below its carrying amount, then goodwill is not considered to be impaired and no further testing is required. If the carrying amount exceeds its fair value, an impairment loss would be recognized equal to the amount of excess, limited to the amount of total goodwill.

Leases

The Company has operating leases for administrative and sales offices, research and development laboratory and clean room. The Company recognizes long-term operating lease rights and commitments as operating lease right-of-use (“ROU”) assets and operating lease liabilities, respectively, in the Consolidated Balance Sheets. The Company elected to not separate lease and non-lease components for all of its leases.

The Company determines if an arrangement is, or contains, a lease at inception. Operating lease ROU assets, and operating lease liabilities are initially recorded based on the present value of lease payments over the lease term. Lease terms include the minimum unconditional term of the lease, and may include options to extend or terminate the lease when it is reasonably certain at the commencement date that such options will be exercised. The decision to include these options involves consideration of the Company’s overall future business plans and other relevant business economic factors that may affect its business. Since the determination of the lease term requires an application of judgment, lease terms that differ in reality from the Company’s initial judgment may potentially have a material impact on the Company’s Consolidated Balance Sheets. In addition, the Company’s leases do not provide an implicit rate. In determining the present value of the Company’s expected lease payments, the discount rate is calculated using the Company’s incremental borrowing rate determined based on the information available, which requires additional judgment.

Software Development Costs

Internally developed software is software developed to meet the Company’s internal needs to provide certain services to the customers. The Company’s capitalized software development costs consist of internal compensation related costs and external direct costs incurred during the application development stage and are amortized over their useful lives, generally for five years.

The costs to develop software that is marketed externally consisting of external direct costs and internal compensation related costs are capitalized once technological feasibility of the software product has been established. Costs incurred prior to establishing technological feasibility are expensed as incurred. Technological feasibility is established when the Company has completed all planning, designing, coding, and testing activities that are necessary to establish that the software product can be produced to meet its design specifications. Capitalization of such costs ceases when the software product is generally available to customers. These software development costs are amortized using the greater of the straight-line method or the usage method over its estimated useful life.

Costs of Revenues

Costs of revenues consist primarily of costs incurred to provide and support the Company’s services, costs recognized in connection with licensing its software, information technology (“IT”) and facilities-related costs and amortization of acquired technology. Service costs include material costs, hardware costs (including cost of leased assets under sales-type leases), personnel-related costs (including compensation, employee benefits, bonus and stock-based compensation expense), subcontractor costs, overhead costs, travel, allocated facilities-related costs and product warranty expense. Software license costs consist of costs associated with cloud-delivery related expenses and licensing third-party software used by the Company in providing services to its customers in solution engagements or sold in conjunction with the Company’s software products.

Research and Development Expenses

Research and development expenses consist primarily of personnel-related costs (including compensation, employee benefits, bonus and stock-based compensation expense), outside development services, travel, third-party cloud-services related costs, IT and facilities cost allocations to support product development activities. Research and development expenses are charged to operations as incurred.

Selling, General and Administrative Expenses

Selling, general and administrative expenses consist primarily of personnel-related costs (including compensation, employee benefits, bonus, commission and stock-based compensation expense for sales, marketing and general and administrative personnel), legal, tax and accounting services, marketing communications and trade conference-related expenses, third-party cloud-services related costs, travel, IT and facilities cost allocations.

Stock-Based Compensation

The Company accounts for stock-based compensation using the fair value method, which requires the Company to measure stock-based compensation based on the grant-date fair value of the awards and recognize the compensation expense over the requisite service period. As stock-based compensation expense recognized is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

The fair value of the Company’s restricted stock units (“RSUs”) is equal to the market value of the Company’s common stock on the date of the grant. These awards are subject to time-based vesting which generally occurs over a period of four years.

The fair value of the Company’s stock options and purchase rights granted under employee stock purchase plan is estimated using the Black-Scholes-Merton option-pricing model, which incorporates various assumptions including volatility, expected life and interest rates. The expected volatility is based on the historical volatility of the Company’s common stock over the most recent period commensurate with the estimated expected life of the Company’s stock options and purchase rights granted under employee stock purchase plan. The expected life is based on historical experience and on the terms and conditions of the stock options granted and purchase rights granted under employee stock purchase plan. The interest rate assumption is based upon observed Treasury yield curve rates appropriate for the expected life of the Company’s stock options and purchase rights granted under employee stock purchase plan.

Income Taxes

The Company’s income tax expense comprises current tax liability and changes in deferred tax assets and liabilities. Deferred tax assets and liabilities are recognized for the expected tax consequences of temporary differences between the tax bases of assets and liabilities. The measurement of current and deferred tax assets and liabilities is based on provisions of enacted tax laws; the effect of future changes in tax laws or rates are not anticipated. Valuation allowances are provided to reduce deferred tax assets to an amount that in management’s judgment is more likely than not to be recoverable against future taxable income. No U.S. taxes are provided on earnings of non-U.S. subsidiaries, to the extent such earnings are deemed to be permanently invested. The Company’s income tax calculations are based on application of applicable U.S. federal and state or foreign tax laws. The Company’s tax filings, however, are subject to audit by the respective tax authorities. Accordingly, the Company recognizes tax liabilities based upon its estimate of whether, and the extent to which, additional taxes will be due when such estimates are more likely than not to be sustained. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. To the extent the final tax liabilities are different from the amounts originally accrued, the increases or decreases are recorded as income tax expense or benefit in the Consolidated Statements of Operations and Comprehensive Income (Loss).

Net Income (Loss) Per Share

Basic net income (loss) per share is computed by dividing net income (loss) by the weighted average number of common shares outstanding for the period. Diluted net income (loss) per share is computed using the weighted average number of common shares outstanding for the period plus the potential effect of dilutive securities which are convertible into common shares (using the treasury stock method), except in cases in which the effect would be anti-dilutive. Dilutive potential common shares consist of incremental common shares issuable upon exercise of stock options, upon vesting of RSUs, contingently issuable shares for all periods and assumed issuance of shares under the Company’s employee stock purchase plan. No dilutive potential common shares are included in the computation of any diluted per share amount when a loss from continuing operations is reported by the Company.

Foreign Currency Translation

The functional currency of the Company’s foreign subsidiaries is the local currency for the respective subsidiary. The assets and liabilities are translated at the period-end exchange rate, and Statements of Operations and Comprehensive Income (Loss) are translated at the average exchange rate during the year. Gains and losses resulting from foreign currency translations are included as a component of other comprehensive income (loss). Gains and losses resulting from foreign currency transactions are included in the Consolidated Statements of Operations and Comprehensive Income (Loss).

Business Combinations

The Company allocates the fair value of purchase consideration to the tangible assets acquired, liabilities assumed and intangible assets acquired based on their estimated fair values at the date of the business combination. The excess of the fair value of purchase consideration over the fair values of these identifiable assets and liabilities is recorded as goodwill. Such valuations require management to make significant estimates and assumptions, especially with respect to intangible assets. Significant estimates in valuing certain intangible assets include, but are not limited to, estimated replacement costs and future expected cash flows from acquired customers, acquired technology, acquired patents, and trade names from a market participant perspective, useful lives and discount rates. Management’s estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ from estimates. Allocation of purchase consideration to identifiable assets and liabilities affects the Company’s amortization expense, as acquired finite-lived intangible assets are amortized over their useful life, whereas any indefinite lived intangible assets, including in-process research and development, and goodwill, are not amortized but tested annually for impairment. During the measurement period, which is not to exceed one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill. Upon the conclusion of the measurement period, any subsequent adjustments are recorded to earnings in the Consolidated Statements of Operations and Comprehensive Income (Loss).

Litigation

From time to time, the Company is subject to various claims and legal proceedings that arise in the ordinary course of business. The Company accrues for losses related to litigation when a potential loss is probable and the loss can be reasonably estimated, and recognizes gains related to litigation at the earlier of when the gain has been realized or when it is realizable in accordance with Financial Accounting Standards Board (“FASB”) requirements. See Note 8, “Commitments and Contingencies.”

Recently Adopted Accounting Pronouncements 

In December 2023, the FASB issued Accounting Standards Update (“ASU”) No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). This ASU included amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The Company adopted this ASU on January 1, 2025 prospectively. Prior period disclosures have not been adjusted to reflect the new disclosure requirements. See required disclosures in Note 11, “Income Taxes.”

Recently Issued Accounting Pronouncements Not Yet Adopted

In November 2024, the FASB issued ASU No. 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This ASU requires the disaggregation of certain expenses in the notes to the consolidated financial statements, to provide enhanced transparency into the expense captions presented on the face of the income statement. This ASU is effective on a prospective basis for fiscal years beginning after December 15, 2026 and for interim periods beginning after December 15, 2027, with early adoption permitted. This ASU may be applied either prospectively or retrospectively. The Company is currently evaluating the impact of the new standard on the consolidated financial statements and related disclosures.

In  July 2025, the FASB issued ASU 2025-05, Measurement of Credit Losses for Accounts Receivable and Contract Assets, which provides a practical expedient to measure credit losses on accounts receivable and contract assets. This ASU is effective for annual periods beginning after  December 15, 2025, and interim periods within those annual reporting periods. Early adoption is permitted. The Company is currently evaluating the timing of the adoption and the impact of the new standard on the consolidated financial statements and related disclosures.

In  September 2025, the FASB issued ASU 2025-06, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40), related to accounting for internal-use software costs. The amendments in this ASU improve the operability of the guidance by removing all references to software development project stages so that the guidance is neutral to different software development methods. This ASU is effective for annual periods beginning after  December 15, 2027, including interim periods within those fiscal years, and permits prospective, modified prospective or retrospective adoption. The Company is currently evaluating the effects of this guidance on its consolidated financial statements and related disclosures. 

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements, which intends to improve the navigability of the guidance in Accounting Standards Codification (“ASC”) 270, Interim Reporting, and clarify when it applies. The amendments also provide additional guidance on what disclosures should be provided in interim reporting periods. This ASU is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years, and permits prospective or full retrospective adoption. Early adoption is permitted. The Company is evaluating the impact of this guidance on its consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-12, Codification Improvements, which addresses suggestions received from stakeholders regarding the Accounting Standards Codification and makes other incremental improvements to U.S. GAAP. The update represents changes to the Codification that clarify, correct errors in or make other improvements to a variety of topics that are intended to make it easier to understand and apply. This ASU is effective for fiscal years beginning after December 15, 2026 and interim periods within those fiscal years. Entities are required to apply the amendments to ASC 260, Earnings Per Share, retrospectively. All other amendments may be applied prospectively or retrospectively. Early adoption is permitted. The Company is evaluating the impact of this guidance on its consolidated financial statements and related disclosures.

Management has reviewed other recently issued accounting pronouncements issued or proposed by the FASB and does not believe any of these accounting pronouncements have had or will have a material impact on the consolidated financial statements.