Note 1 - Basis of Presentation	9 Months Ended
Sep. 30, 2025
Notes to Financial Statements
Significant Accounting Policies [Text Block]	1. BASIS OF PRESENTATION The accompanying unaudited condensed consolidated financial statements of Monolithic Power Systems, Inc., a Delaware corporation, and its wholly owned subsidiaries (the “Company” or “MPS”) have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted in accordance with these accounting principles, rules and regulations. All intercompany accounts and transactions have been eliminated. The information in this report should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 3, 2025. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary to present fairly the Company’s financial position, results of operations and cash flows for the interim periods presented. The financial statements contained in this Quarterly Report on Form 10-Q are not necessarily indicative of the results that may be expected for the year ending December 31, 2025 or for any other future periods. *Summary of Significant Accounting Policies* There have been no changes to the Company’s significant accounting policies during the three and nine months ended September 30, 2025 from those described in the Company’s audited consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2024. *Use of Estimates* The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions used in these condensed consolidated financial statements primarily include those related to income tax valuation allowances, inventory valuation and stock-based compensation. Actual results could differ from these estimates and assumptions, and any such differences may be material to the Company’s condensed consolidated financial statements. *New Accounting Pronouncements Not Yet Adopted as of September 30, 2025* In December 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which aims to improve an entity’s income tax disclosures around its effective rate reconciliation, income taxes paid, disaggregation of income before income taxes and income tax expense. The Company will adopt this standard in its Form 10-K for the fiscal year ending December 31, 2025. The adoption of this standard will result in expanded disclosures in the Notes to Consolidated Financial Statements. In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which aims to provide more detailed information about the types of expenses in commonly presented expense captions. The Company will adopt this standard in its Form 10-K for the fiscal year ending December 31, 2027. The Company is evaluating the impact of adoption on its Consolidated Financial Statements.

Note 1 - Basis of Presentation

9 Months Ended

Sep. 30, 2025

Significant Accounting Policies [Text Block]

1. BASIS OF PRESENTATION

The accompanying unaudited condensed consolidated financial statements of Monolithic Power Systems, Inc., a Delaware corporation, and its wholly owned subsidiaries (the “Company” or “MPS”) have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted in accordance with these accounting principles, rules and regulations. All intercompany accounts and transactions have been eliminated. The information in this report should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 3, 2025.

In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary to present fairly the Company’s financial position, results of operations and cash flows for the interim periods presented. The financial statements contained in this Quarterly Report on Form 10-Q are not necessarily indicative of the results that may be expected for the year ending December 31, 2025 or for any other future periods.

Summary of Significant Accounting Policies

There have been no changes to the Company’s significant accounting policies during the three and nine months ended September 30, 2025 from those described in the Company’s audited consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2024.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions used in these condensed consolidated financial statements primarily include those related to income tax valuation allowances, inventory valuation and stock-based compensation. Actual results could differ from these estimates and assumptions, and any such differences may be material to the Company’s condensed consolidated financial statements.

New Accounting Pronouncements Not Yet Adopted as of September 30, 2025

In December 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which aims to improve an entity’s income tax disclosures around its effective rate reconciliation, income taxes paid, disaggregation of income before income taxes and income tax expense. The Company will adopt this standard in its Form 10-K for the fiscal year ending December 31, 2025. The adoption of this standard will result in expanded disclosures in the Notes to Consolidated Financial Statements.

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which aims to provide more detailed information about the types of expenses in commonly presented expense captions. The Company will adopt this standard in its Form 10-K for the fiscal year ending December 31, 2027. The Company is evaluating the impact of adoption on its Consolidated Financial Statements.