75000 - Document - Cover Page
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75010 - Statement - CONSOLIDATED BALANCE SHEETS
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75020 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)
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75030 - Statement - Consolidated Statements of Operations
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75040 - Statement - Consolidated Statements of Comprehensive (Loss) Income
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75050 - Statement - Consolidated Statements of Comprehensive (Loss) Income (Parenthetical)
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75060 - Statement - Consolidated Statements of Changes in Stockholders' Equity
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75070 - Statement - Consolidated Statements of Cash Flows
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75080 - Disclosure - Cybersecurity Risk Management, Strategy and Governance
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995457 - Disclosure - Nature of the Business and Basis of Presentation
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995467 - Disclosure - Summary of Significant Accounting Policies
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995477 - Disclosure - Business Combinations
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995487 - Disclosure - Revenue from Contracts with Customers
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995497 - Disclosure - Fair Value Measurements
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995507 - Disclosure - Trade Accounts Receivable, Net
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995517 - Disclosure - Inventories
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995527 - Disclosure - Property, Plant and Equipment, Net
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995537 - Disclosure - Goodwill and Intangible Assets
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995547 - Disclosure - Other Assets, Net
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995557 - Disclosure - Accrued Expenses and Other Current Liabilities
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995567 - Disclosure - Leases
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995577 - Disclosure - Debt and Other Borrowings
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995587 - Disclosure - Other Long-Term Liabilities
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995597 - Disclosure - Retirement Plans
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995607 - Disclosure - Commitment and Contingencies
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995617 - Disclosure - Net (Loss) Income per Share
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995627 - Disclosure - Stock-Based Compensation
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995637 - Disclosure - Income Taxes
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995647 - Disclosure - Restructurings
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995657 - Disclosure - Related Party Transactions
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995667 - Disclosure - Summary of Significant Accounting Policies (Policies)
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995677 - Disclosure - Summary of Significant Accounting Policies (Tables)
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995687 - Disclosure - Business Combinations (Tables)
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995697 - Disclosure - Revenue from Contracts with Customers (Tables)
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995707 - Disclosure - Fair Value Measurements (Tables)
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995717 - Disclosure - Trade Accounts Receivable, Net (Tables)
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995727 - Disclosure - Inventories (Tables)
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995737 - Disclosure - Property, Plant and Equipment, Net (Tables)
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995747 - Disclosure - Goodwill and Intangible Assets (Tables)
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995757 - Disclosure - Other Assets, Net (Tables)
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995767 - Disclosure - Accrued Expenses and Other Current Liabilities (Tables)
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995777 - Disclosure - Leases (Tables)
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995787 - Disclosure - Debt and Other Borrowings (Tables)
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995797 - Disclosure - Other Long-Term Liabilities (Tables)
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995807 - Disclosure - Retirement Plans (Tables)
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995817 - Disclosure - Net (Loss) Income per Share (Tables)
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995827 - Disclosure - Stock-Based Compensation (Tables)
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995837 - Disclosure - Income Taxes (Tables)
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995847 - Disclosure - Restructurings (Tables)
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995857 - Disclosure - Nature of the Business and Basis of Presentation (Details)
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995867 - Disclosure - Summary of Significant Accounting Policies - Business Segment Information - Additional Information (Details)
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995877 - Disclosure - Summary of Significant Accounting Policies - Non-controlling Interest - Additional Information (Details)
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995887 - Disclosure - Summary of Significant Accounting Policies - Property, Plant and Equipment (Details)
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995897 - Disclosure - Summary of Significant Accounting Policies - Intangible assets, net - Additional Information (Details)
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995907 - Disclosure - Summary of Significant Accounting Policies - Product Warranties - Additional Information (Details)
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995917 - Disclosure - Summary of Significant Accounting Policies - Contract Assets and Contract Liabilities - Additional Information (Details)
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995927 - Disclosure - Summary of Significant Accounting Policies - Concentrations of Credit Risk and Significant Customers - Additional Information (Details)
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995937 - Disclosure - Summary of Significant Accounting Policies - Recently Accounting Pronouncements - Additional Information (Details)
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995947 - Disclosure - Business Combinations - Crocus - Additional Information (Details)
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995957 - Disclosure - Business Combinations - Summary of Preliminary Price Allocation (Details)
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995967 - Disclosure - Revenue from Contracts with Customers - Net Sales by Core End Market and Application (Details)
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995977 - Disclosure - Revenue from Contracts with Customers - Net Sales by Product (Details)
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995987 - Disclosure - Revenue from Contracts with Customers - Net Sales by Geography (Details)
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995997 - Disclosure - Revenue from Contracts with Customers - Additional Information (Details)
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996007 - Disclosure - Fair Value Measurements - Assets And Liabilities Measured At Fair Value (Details)
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996017 - Disclosure - Fair Value Measurements - Unrealized Gains and Losses on Marketable Securities with a Readily Determinable Fair Value (Details)
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996027 - Disclosure - Fair Value Measurements - Additional Information (Details)
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996037 - Disclosure - Fair Value Measurements - Change in Fair Value of Level 3 Contingent Consideration (Details)
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996047 - Disclosure - Trade Accounts Receivable, Net - Summary of Trade Accounts Receivable (Details)
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996057 - Disclosure - Inventories - Schedule of Inventories (Details)
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996067 - Disclosure - Inventories - Narrative (Details)
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996077 - Disclosure - Property, Plant and Equipment, Net - Schedule of Property, Plant, and Equipment (Details)
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996087 - Disclosure - Property, Plant and Equipment, Net - Narrative (Details)
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996097 - Disclosure - Property, Plant and Equipment, Net - Schedule of Long Lived Assets (Details)
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996107 - Disclosure - Goodwill and Intangible Assets - Summary of Changes in Carrying Amount of Goodwill (Details)
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996117 - Disclosure - Goodwill and Intangible Assets - Schedule of Intangible Assets, Net (Details)
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996127 - Disclosure - Goodwill and Intangible Assets - Narrative (Details)
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996137 - Disclosure - Goodwill and Intangible Assets - Future Amortization Expense (Details)
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996147 - Disclosure - Leases - Maturity Schedule (Details)
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996157 - Disclosure - Other Assets, Net (Details)
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996167 - Disclosure - Accrued Expenses and Other Current Liabilities (Details)
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996177 - Disclosure - Leases - Additional Information (Details)
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996187 - Disclosure - Leases - Operating Lease (Details)
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996197 - Disclosure - Leases - Finance Lease (Details)
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996207 - Disclosure - Leases - Schedule of Future Minimum Lease Payments under Operating and Finance Leases (Details)
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996217 - Disclosure - Leases - Schedule of Future Minimum Lease Payments under Operating and Finance Leases (Details) 2
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996227 - Disclosure - Leases - Schedule of Future Minimum Lease Payments under Operating and Finance Leases (Details) 3
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996237 - Disclosure - Debt and Other Borrowings - Schedule of Debt Obligations (Details)
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996247 - Disclosure - Debt and Other Borrowings - Schedule of Debt Obligations (Details) 2
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996257 - Disclosure - Debt and Other Borrowings - Additional Information (Details)
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996267 - Disclosure - Other Long-Term Liabilities (Details)
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996277 - Disclosure - Retirement Plans - Schedule of Expense Related to Defined Benefit Plan (Details)
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996287 - Disclosure - Retirement Plans - Schedule of Changes in Benefit Obligations and Plan Assets (Details)
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996297 - Disclosure - Retirement Plans - Obligations and Asset Information for Defined Benefit Plans with Projected Benefit Obligation in Excess of Plan Assets (Details)
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996307 - Disclosure - Retirement Plans - Change in Amounts Recognized in AOCI (Details)
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996317 - Disclosure - Retirement Plans - Schedule of Weighted-Average Assumptions (Details)
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996327 - Disclosure - Retirement Plans - Fair Value of Entity's Plan Assets (Details)
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996337 - Disclosure - Retirement Plans - Schedule of Amounts Recorded for AOCI for Defined Benefit Plan (Details)
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996347 - Disclosure - Retirement Plans - Schedule of Changes in Fair Value of Level 3 Plan Assets (Details)
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996357 - Disclosure - Retirement Plans - Defined Benefit Plans, Additional Information (Details)
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996367 - Disclosure - Retirement Plans - Schedule of Estimated Future Benefit Payments (Details)
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996377 - Disclosure - Retirement Plans - Defined Contribution Plans, Additional Information (Details)
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996387 - Disclosure - Commitment and Contingencies (Details)
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996397 - Disclosure - Net (Loss) Income per Share - Narrative (Details)
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996407 - Disclosure - Net (Loss) Income per Share - Schedule of Computation of Net (Loss) Income per Share (Details)
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996417 - Disclosure - Net (Loss) Income per Share - Schedule of Issuable Weighted Average Share Information (Details)
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996427 - Disclosure - Stock-Based Compensation - Narrative (Details)
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996437 - Disclosure - Stock-Based Compensation - Schedule of RSU and PSU Activity (Details)
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996447 - Disclosure - Stock-Based Compensation - Schedule of Performance Units Fair Value Assumptions (Details)
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996457 - Disclosure - Stock-Based Compensation - Schedule of ESPP Fair Value Assumptions (Details)
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996467 - Disclosure - Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details)
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996477 - Disclosure - Income Taxes - Schedule of Components of (Loss) Income before Income Taxes (Details)
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996487 - Disclosure - Income Taxes - Schedule of Significant Components of Income Taxes (Benefit) Provision (Details)
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996497 - Disclosure - Income Taxes - Schedule of Income Taxes Reconciliation (Details)
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996507 - Disclosure - Income Taxes - Narrative (Details)
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996517 - Disclosure - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details)
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996527 - Disclosure - Income Taxes - Unrecognized Tax Benefits (Details)
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996537 - Disclosure - Restructurings - Additional Information (Details)
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996547 - Disclosure - Restructurings - Summary of Severance, Exit Costs, and Other Charges, Net (Details)
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996557 - Disclosure - Restructurings - Summary of Restructuring, Exit Costs, and Other Charges, Net Included in Statement of Operations (Details)
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996567 - Disclosure - Restructurings - Summary of Changes in Accrual for Employee Severance and Related Expenses (Details)
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996577 - Disclosure - Related Party Transactions (Details)
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Acquisition-related costs
Business Combination, Acquisition-Related Cost, Expense
Transfer Of Property, Plant, And Equipment, Net To Held-for-sale
Transfer Of Property, Plant, And Equipment, Net To Held-for-sale
Assets held for sale transferred from property, plant and equipment, net
One Equity Partners
One Equity Partners [Member]
OEP
Buildings improvements
Building Improvements [Member]
Retirement Plan Type [Axis]
Retirement Plan Type [Axis]
Increase (Decrease) In Accrued Liabilities And Other Current And Long-Term Liabilities
Increase (Decrease) In Accrued Liabilities And Other Current And Long-Term Liabilities
Accrued expenses and other current and long-term liabilities
Income (Loss) from Continuing Operations before Income Taxes, Foreign
Foreign operations
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation
Projected benefit obligations
Restructuring Reserve
Restructuring Reserve, Total
Beginning Balance
Ending Balance
Concentration Risk Type [Axis]
Concentration Risk Type [Axis]
Schedule of Nonvested Performance-Based Units Activity [Table Text Block]
Summary of Performance Stock Units Activity
Schedule of Revenues from External Customers and Long-Lived Assets [Table]
Schedule of Revenues from External Customers and Long-Lived Assets [Table]
Finance lease liabilities
Total lease liabilities
Finance Lease, Liability
Finance Lease, Liability, Total
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Finance Lease, Liability, to be Paid, Year Four
2030
Preferred Stock, Shares Issued
Preferred stock, shares issued (in shares)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value
Ending balance
Beginning balance
Underwriting discount
Underwriting Discounts
Underwriting discounts
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Non-cash transactions:
Total long-term debt and finance lease liabilities, less current portion
Long-term debt
Long-Term Debt, Excluding Current Maturities
Business Combination, Contingent Consideration, Change in Contingent Consideration, Liability, Increase (Decrease)
Change in fair value of contingent consideration
Schedule of Debt Obligations
Schedule of Long-Term Debt Instruments [Table Text Block]
Entity Current Reporting Status
Entity Current Reporting Status
Accrued Contingent Consideration
Accrued contingent consideration.
Accrued contingent consideration
Remaining unpaid consideration
Japan
JAPAN
Operating Expenses [Abstract]
Operating expenses:
Fair Value, Inputs, Level 2 [Member]
Level 2
Deferred Tax Assets, Net of Valuation Allowance
Total deferred income tax assets
Commitments and Contingencies Disclosure [Text Block]
Commitments and Contingencies
Common Stock, Shares Authorized
Common stock, shares authorized (in shares)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Finite-Lived Intangible Asset, Expected Amortization, Year Four
2030
Deferred Tax Assets, Capital Loss Carryforwards
Net capital losses
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested
Aggregate Intrinsic Value
Product and Service [Axis]
Product and Service [Axis]
Document Fiscal Period Focus
Document Fiscal Period Focus
Total lease payments
Finance Lease, Liability, to be Paid
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-Term Rate of Return on Plan Assets
Non-U.S. expected long-term return on plan assets
Debt Instrument, Interest Rate, Stated Percentage
Interest rate
Revenue from Contract with Customer [Abstract]
Entity Shell Company
Entity Shell Company
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax
Change in AOCI for non-U.S. defined benefit plan
Mr. Max Glover [Member]
Mr. max glover.
Segment Reporting, Policy [Policy Text Block]
Segment Information
Cash and Cash Equivalent
Cash and cash equivalents at end of period
Cash and cash equivalents at beginning of period
Cash and cash equivalents
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax
Net actuarial loss
Defined Benefit Plan, Benefit Obligation
Benefit obligation at end of year
Benefit obligation at beginning of year
Defined Benefit Plan, Expected Future Benefit Payment, Year Two
2028
Cybersecurity Risk Management, Strategy, and Governance [Abstract]
Common Stock, Shares, Issued
Common stock, shares issued (in shares)
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]
Cybersecurity Risk Board of Directors Oversight [Text Block]
Short-Term Debt [Table]
Statement [Table]
Statement [Table]
Gross increases - tax positions for current period
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions
Right-of-use assets obtained in exchange for lease liabilities
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability
Noncontrolling Interest [Table]
Noncontrolling Interest [Table]
Total purchase consideration
Payments to Acquire Businesses, Gross
Preliminary purchase price
Total estimated fair value of consideration
Share-Based Compensation Arrangement by Share-Based Payment Award, Purchase Price of Common Stock, Percent
Purchase price of common stock, percentage of fair market value
Defined Benefit Plan, Benefit Obligation, Unrecognized Prior Service (Credit) Cost
Defined Benefit Plan, Benefit Obligation, Unrecognized Prior Service (Credit) Cost
Prior service cost
Statement [Line Items]
Statement [Line Items]
Business Combination [Domain]
Business Acquisition, Acquiree [Domain]
Revenue from Contract with Customer [Policy Text Block]
Revenue Recognition
Entity Filer Category
Entity Filer Category
Reclassification, Comparability Adjustment [Policy Text Block]
Reclassifications
Facilitation fee
Facilitation Fee
Facilitation fee
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Indefinite-Lived
In-process research and development
Liabilities and Equity
Total liabilities, non-controlling interest and stockholders' equity
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Total
Business Combination, Recognized Liability Assumed, Liability, Current
Current liabilities assumed
Debt Instrument [Line Items]
Payables and Accruals [Abstract]
Current portion of long-term debt and finance lease obligations
Current portion of long-term debt
Long-Term Debt, Current Maturities
Long-Term Debt, Current Maturities, Total
Restructuring Type [Axis]
Long-Lived Tangible Asset [Axis]
Long-Lived Tangible Asset [Axis]
Severance Costs
Severance
Finance Lease, Liability, to be Paid, Year Three
2029
Fair Value, by Balance Sheet Grouping [Table Text Block]
Fair Value, by Balance Sheet Grouping
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]
Wafer Foundry Agreement
Wafer Foundry Agreement [Member]
Wafer Foundry Agreement
Restructuring and Related Costs [Table Text Block]
Summary of Severance, Exit Costs, and Other Charges, Net
Income Taxes Receivable, Noncurrent
Income taxes receivable long-term
Revenue from External Customers by Products and Services [Table Text Block]
Revenue from External Customers by Products and Services
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill [Abstract]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Excess shares issued due to achievement of performance conditions (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Excess Shares Issued in Period
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Excess Shares Issued in Period
Cash and Cash Equivalents, Fair Value Disclosure
Money market fund deposits
Deferred Tax Assets, Valuation Allowance
Valuation allowance for deferred income tax assets
Valuation allowance for deferred income tax assets
Two Thousand Twenty Five Refinancing and Repricing of Refinanced Two Thousand Twenty Three Term Loan Facility [Member]
Two thousand twenty five refinancing and repricing of refinanced two thousand twenty three term loan facility.
2025 Refinancing and Repricing of Refinanced 2023 Term Loan Facility
Extinguishment of Debt, Amount
Extinguishment of Debt, Amount
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
U.S. federal statutory tax rate
Cybersecurity Risk Management Third Party Engaged [Flag]
Documents Incorporated by Reference [Text Block]
Documents Incorporated by Reference
Ending balance
Beginning balance
Goodwill, Total
Goodwill
Goodwill
Effective Income Tax Rate Reconciliation, Percent
Effective tax rate
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]
Interest income
Investment Income, Interest
Decrease in interim income tax benefit
Decrease in Income Tax Benefit
Decrease in income tax benefit.
Decrease in benefit for income taxes
Income Tax Jurisdiction [Axis]
Share Repurchase Agreement [Member]
Share Repurchase Agreement
Share Repurchase Agreement
Geographical [Domain]
Geographical [Domain]
Payments to Acquire Intangible Assets
Purchases of intangible assets
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Issued in Period
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Issued in Period
Issued (in shares)
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
Maximum employer contribution
PHILIPPINES
Philippines
Schedule of Inventory, Current [Table Text Block]
Schedule of Inventories
Unamortized debt issuance costs
Debt Issuance Costs, Net
Debt Issuance Costs, Net, Total
Property, plant and equipment, net
Deferred Tax Assets, Property, Plant and Equipment
Repayments of other debt
Repayment of Other Debt
Repayment of other debt.
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation
Payments of taxes withheld on net settlement of equity awards
Defined Benefit Plan, Plan Assets, Benefits Paid
Benefits paid
Related Party
Related Party [Member]
Debt Instrument, Covenant, Leverage Ratio, Maximum
Debt Instrument, Covenant, Leverage Ratio, Maximum
Leverage ratio
Significant Accounting Policies [Text Block]
Summary of Significant Accounting Policies
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Mr. Michael Doogue [Member]
Mr. michael doogue.
Proceeds from Issuance of Secured Debt
Net proceeds from Refinanced 2023 Term Loan Facility
Borrowings of 2023 term loan facility, net of deferred financing costs
Finite-Lived Intangible Asset, Useful Life
Weighted-Average Lives
Estimated useful life
Concentration Risk [Table]
Concentration Risk [Table]
Non-Related Party Revenue
Non-Related Party Revenue [Member]
Non-Related Party Revenue
Pension and Other Post Retirement Benefits Plans, Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax
Pension and Other Post Retirement Benefits Plans, Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Roll Forward]
Total
Effective Income Tax Rate Reconciliation, Deferred Tax Remeasurement, Amount
Effective Income Tax Rate Reconciliation, Deferred Tax Remeasurement, Amount
Deferred tax remeasurement
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Cybersecurity Risk Management, Strategy, and Governance [Table]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Schedule of Computation of Net (Loss) Income per Share and Unaudited Pro Forma Net Income per Share
Increase (Decrease) in Other Operating Assets and Liabilities, Net
Increase (Decrease) in Other Operating Assets and Liabilities, Net, Total
Other changes in operating assets and liabilities, net
Other changes in operating assets and liabilities, net
Increase (Decrease) in Other Receivables
Accounts receivable - other
Related Party Transaction, Term
Related Party Transaction, Term
Related party transaction, term
Earnings Per Share, Basic, Total
Basic (in dollars per share)
Basic net income attributable to Allegro MicroSystems, Inc. per share (in dollars per share)
Basic net (loss) income per common share attributable to Allegro MicroSystems, Inc. stockholders
Disaggregation of Revenue [Table Text Block]
Net Sales by Core End Market and Application
Retirement Benefits [Text Block]
Retirement Plans
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate
Non-U.S. assumed discount rate
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Foreign currency translation adjustment
Repayments of Secured Debt
Repayment of 2020 term loan facility
Revolving Credit Facility [Member]
Senior Secured Revolving Credit Facility
Retirement Plan Type [Domain]
Retirement Plan Type [Domain]
Liabilities, Current
Total current liabilities
Increase (Decrease) in Accounts Receivable
Trade accounts receivable
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Lessee, Operating Lease, Liability, to be Paid, Year Five
2031
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from External Customers and Long-Lived Assets [Line Items]
Effective Income Tax Rate Reconciliation, Cross-Border, Other, Amount
Other
Changes in unrecognized tax benefits
Effective Income Tax Rate Reconciliation, Changes in Unrecognized Tax Benefits, Amount
Effective income tax rate reconciliation, changes in unrecognized tax benefits, amount.
Changes in unrecognized tax benefits
Entity restructuring
Effective Income Tax Rate Reconciliation, Disposition of Business, Amount
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax
Prior service costs
Inventory, Finished Goods, Net of Reserves
Finished goods
Domestic Tax Authority
Domestic Tax Jurisdiction [Member]
Tax credits
Effective Income Tax Rate Reconciliation, Tax Credit, Percent [Abstract]
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions
Gross increases - tax positions for prior periods
Schedule of share-based payment award equity instruments other than options valuation assumptions.
Schedule of Share-based Payment Award, Equity Instruments Other than Options, Valuation Assumptions [Table Text Block]
Schedule of Performance Units Fair Value Assumptions
Entity Small Business
Entity Small Business
Retained Earnings (Accumulated Deficit)
Accumulated deficit
Defined Benefit Plan, Funded (Unfunded) Status of Plan
Underfunded status at end of year
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost
Stock-based compensation
Payments of debt issuance costs
Repayments of Unsecured Debt
Share-Based Compensation Arrangement By Share-Based Payment Award, Inclusion Percentage Of Target Goals
Share-Based Compensation Arrangement By Share-Based Payment Award, Inclusion Percentage Of Target Goals
Inclusion percentage of target goals
Preferred Stock [Member]
Preferred Stock
Geographic Concentration Risk [Member]
Geographic Concentration Risk
Equity Offering
Equity Offering [Member]
Equity Offering
Entity Well-known Seasoned Issuer
Entity Well-known Seasoned Issuer
Current Foreign Tax Expense (Benefit)
Foreign
Subsequent Events Considerations
Subsequent Events, Policy [Policy Text Block]
Operating leases
Operating Lease, Assets And Liabilities, Lessee
Operating Lease, Assets And Liabilities, Lessee [Abstract]
Sanken
Sanken [Member]
Sanken Electric Co., Ltd.
Sanken
Share-Based Payment Arrangement [Text Block]
Stock-Based Compensation
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Defined Contribution Plan [Table]
Defined Contribution Plan [Table]
Leases [Abstract]
Loans Payable [Member]
Loans Payable
Weighted Average Number of Shares Outstanding, Diluted, Adjustment
Dilutive effect of common stock equivalents (in shares)
Dilutive effect of common stock equivalents (in shares)
Contract with Customer, Liability
Contract liabilities
Lessee, Lease, Description [Line Items]
Lessee, Lease, Description [Line Items]
Amendment Flag
Amendment Flag
Product and Service [Domain]
Product and Service [Domain]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount
Income tax (benefit) provision at U.S. statutory rate
Inventory Disclosure [Text Block]
Inventories
Facilitation fee included in transaction expenses
Facilitation Fee Included In Transaction Expenses
Facilitation fee included in transaction expenses.
Crocus
Crocus [Member]
Crocus.
Interest on lease liabilities
Finance Lease, Interest Expense
Earnings Per Share, Policy [Policy Text Block]
Net (Loss) Income Per Share
Concentration Risk [Line Items]
Concentration Risk [Line Items]
Disposal Group, Including Discontinued Operation, Assets, Current
Disposal Group, Including Discontinued Operation, Assets, Current, Total
Assets held for sale
Liabilities and Equity [Abstract]
Liabilities, Non-Controlling Interest and Stockholders' Equity
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation
Net cash provided by operating activities
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description
Common Stock [Member]
Common Stock
Accrued warranty reserves
Product Warranty Accrual, Current
Accrued warranty costs
Inventories
Business Combination, Recognized Asset Acquired, Inventory, Current
Cybersecurity Risk Role of Management [Text Block]
Tax credit carryforward
Tax Credit Carryforward, Amount
Defined Contribution Plan, Employer Discretionary Contribution Amount
Company contributions
Lessee, Operating Lease, Liability, to be Paid, Year Three
2029
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Less accumulated depreciation
Entity Address, Address Line One
Entity Address, Address Line One
Deferred Tax Liabilities, Gross
Total deferred income tax liabilities
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Earnings Per Share [Abstract]
Net (loss) income per common share attributable to Allegro MicroSystems, Inc.:
Income Tax, Policy [Policy Text Block]
Income Taxes
Loss Contingency Accrual
Indemnification accruals
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]
Supplemental disclosures of cash flow information:
Supplemental Cash Flow Information [Abstract]
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Foreign Currency Transaction and Translations
Goodwill and Intangible Assets Disclosure [Text Block]
Goodwill and Intangible Assets
Pension and Other Postretirement Benefit Plans, Accumulated Net Gains Losses
Pension and Other Postretirement Benefit Plans, Accumulated Net Gains Losses [Roll Forward]
Net Actuarial Loss
Defined Benefit Plan, Expected Future Benefit Payment, Year Four
2030
Operating lease right-of-use assets, net
Operating Lease, Right-of-Use Asset
Operating lease, right-of-use asset
Less: imputed interest
Finance Lease, Liability, Undiscounted Excess Amount
Defined Benefit Plan, Plan Assets, Category [Domain]
Defined Benefit Plan, Plan Assets, Category [Domain]
Deferred Tax Assets, Gross
Gross deferred income tax assets
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]
Net income attributable to non-controlling interests
Net Income (Loss) Attributable to Noncontrolling Interest
Net income attributable to non-controlling interests
Effective Income Tax Rate Reconciliation Nondeductible Expense Executive Compensation Percent
Effective Income Tax Rate Reconciliation Nondeductible Expense Executive Compensation Percent
162(m) limitation
Payments to Acquire Debt Securities, Available-for-Sale
Investment in debt security
Inventory Disclosure [Abstract]
Largest Distributor
Largest Distributor [Member]
Largest Distributor
Document Type
Document Type
Income Taxes Paid, Net
Cash paid for income taxes, net of refunds
Gross Profit
Gross profit
Noncontrolling Interest, Ownership Percentage by Parent
Ownership percentage by majority shareholder
Entity Central Index Key
Entity Central Index Key
Accounts Receivable, Allowance for Credit Loss, Current
Balance at the end of the period
Balance at the beginning of the period
Allowances for doubtful accounts
Provision for expected credit losses
Allegro Microsystems, Inc.
Allegro Microsystems, Inc. [Member]
Allegro Microsystems, Inc.
Line of Credit Facility [Table]
Line of Credit Facility [Table]
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]
Current portion of related party notes receivable
Nontrade Receivables, Current
Nontrade Receivables, Current, Total
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation
Net increase (decrease) in cash and cash equivalents and restricted cash
Subsequent Event Type [Domain]
Antidilutive securities excluded from computation of net income per share (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Equity method and other investments
Deferred Tax Assets, Equity Method Investments
Deferred tax assets, equity method of accounting
Repurchases of common stock
Stock Repurchased and Retired During Period, Shares
Impairment of Long-Lived Assets to be Disposed of
Impairment of assets held for sale
Impairment of assets held for sale
Common Stock, Par or Stated Value Per Share
Common stock, par value (in dollars per share)
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Shares Cancelled In Period
Share based compensation arrangement by share based payment award equity instruments other than options shares cancelled in period.
Cancelled
Deferred Income Taxes and Other Liabilities [Abstract]
Deferred income tax liabilities:
Base Rate
Base Rate [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)
Foreign currency exchange rate changes
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest [Abstract]
(Loss) income before income taxes
Document Financial Statement Error Correction [Flag]
Other Restructuring Costs
Other
Debt Disclosure [Abstract]
Expected restructuring charges
Restructuring and Related Cost, Expected Cost
Accounts Receivable, Allowance For Returns And Sales, Current
Accounts Receivable, Allowance For Returns And Sales, Current
Balance at the end of the period
Balance at the beginning of the period
Returns and sales allowances
Cost of Sales [Member]
Cost of sales
Cost of Goods Sold
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Ownership [Domain]
Ownership [Domain]
Current Fiscal Year End Date
Current Fiscal Year End Date
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)
Actual return on plan assets
Other Noncurrent Liabilities [Table Text Block]
Schedule of Other Long-Term Liabilities
Long-Lived Assets by Geographic Areas [Table Text Block]
Schedule of Long-lived Assets
Share-Based Compensation Arrangement By Share-Based Payment Award, Additional Number Of Shares That May Become Available For Grant
Share-Based Compensation Arrangement By Share-Based Payment Award, Additional Number Of Shares That May Become Available For Grant
Number of shares that may become available for grant (in shares)
Other assets
Business Combination, Recognized Asset Acquired, Other Asset, Noncurrent
Receivables [Abstract]
Customer Relationships [Member]
Customer relationships
Fair Value, by Balance Sheet Grouping [Table]
Fair Value, by Balance Sheet Grouping [Table]
Related Party Transaction, Distribution Agreement Terms
Related Party Transaction, Distribution Agreement Terms
Distribution agreement period
Entity Address, State or Province
Entity Address, State or Province
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Ending balance (in shares)
Beginning balance (in shares)
Other Countries
Other Countries [Member]
Other
Severance and Other Employee-related Benefit Charges
Severance and other employee-related benefit charges.
Severance and other employee-related benefit charges
Affiliated Entity In Philippines
Affiliated Entity In Philippines [Member]
Affiliated Entity in Philippines
Debt Issuance Costs, Gross
Debt issuance costs recognized
Preferred stock, ending balance (in shares)
Preferred stock, beginning balance (in shares)
Preferred Stock, Shares Outstanding
Preferred stock, shares outstanding (in shares)
Comprehensive income attributable to Allegro MicroSystems, Inc
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Comprehensive (loss) income attributable to Allegro MicroSystems, Inc.
Effective Income Tax Rate Reconciliation, Cross-Border Tax Effect, Percent [Abstract]
Effect of cross-border tax laws:
Research and Development Expense, Policy [Policy Text Block]
Research and Development
Common Stock, Capital Shares Reserved for Future Issuance
Common stock reserved for future issuance (in shares)
Liability, Retirement and Postemployment Benefits
Accrued retirement and defined benefit plan obligation
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax
Defined benefit plan, tax
Less: tax benefit
Defined Benefit Plan, Assumptions [Table Text Block]
Schedule of Weighted-Average Assumptions
Geographical [Axis]
Geographical [Axis]
Line of Credit Facility, Lender [Domain]
Line of Credit Facility, Lender [Domain]
Stockholders' Equity Attributable to Noncontrolling Interest
Non-controlling interest
Accounts Payable, Trade, Current
Trade accounts payable
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount
State and local income tax, net of federal income tax effect
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
Schedule of Stock-Based Compensation Expense
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount
Other
Thereafter
Finance Lease, Liability, to be Paid, after Year Five
Tax Credit Carryforward, Valuation Allowance
Tax credit carryforward, valuation allowance
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]
Accrued Expenses and Other Current Liabilities
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive (loss) income:
PSUs
Performance Shares [Member]
Performance Stock Units (PSUs)
Deferred Income Tax Assets, Net
Deferred income tax assets
Proceeds from Sale and Maturity of Marketable Securities
Sales in marketable securities
Fair value of long-term debt
Long-Term Debt, Fair Value
Subsequent Event
Subsequent Event [Member]
Property, Plant and Equipment [Abstract]
Other assets
Other Assets, Noncurrent
Total
Term loan facility.
Term Loan Facility [Member]
Term Loan Facility
Deferred Tax Assets, Inventory
Inventory and sales related
Wafer Foundry Agreement, Forecast Term
Wafer Foundry Agreement, Forecast
Wafer Foundry Agreement, Forecast [Member]
Prepaid expenses and other current assets
Business Combination, Recognized Asset Acquired, Prepaid Expense and Other Asset, Current
Other Long-term Liabilities, Noncurrent
Other Long-term Liabilities, Noncurrent
Other long-term liabilities
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value
Fair value vested
Intangible Assets, Net
Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]
Income Tax Paid, Foreign, after Refund Received
Income Tax Paid, Foreign, after Refund Received, Total
Net foreign payments
Sanken Distribution Agreement, One-Time Payment
Sanken Distribution Agreement, One-Time Payment [Member]
Sanken Distribution Agreement, One-Time Payment
Share-Based Payment Arrangement, Expense, after Tax
Total stock-based compensation expense, net of taxes
Related Party Transaction [Axis]
Related Party Transaction [Axis]
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Loss
Customer [Domain]
Customer [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Asset, Expected Amortization, after Year Five
Thereafter
Cash and Cash Equivalents [Domain]
Cash and Cash Equivalents [Domain]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Schedule of Future Minimum Lease Payments under Operating and Finance Leases
Lessee Operating and Finance Lease Liability Maturity [Table Text Block]
Lessee operating and finance lease liability maturity.
Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Tax
Ending balance
Beginning balance
Preliminary purchase price
Business Combination, Consideration Transferred
Business Combination, Consideration Transferred, Total
Total purchase price of acquired certain intellectual property
Effective Income Tax Rate Reconciliation, Gain On Contingent Purchase Price Reduction, Amount
Effective Income Tax Rate Reconciliation, Gain On Contingent Purchase Price Reduction, Amount
Gain on contingent purchase price reduction
Preferred Stock, Value, Issued
Preferred Stock, $0.01 par value; 20,000,000 shares authorized, no shares issued or outstanding at March 27, 2026 and March 28, 2025
Intangible assets
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Finite-Lived
Completed technology
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred:
Selling, General and Administrative Expense
Selling, general and administrative
Selling, General and Administrative Expense, Total
Selling, general and administrative expenses
Maturity date
Debt Instrument, Maturity Date
Defined Benefit Plan, Equity Securities [Member]
Stocks and other investments
Minimum [Member]
Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value
Grant date fair value (in dollars per share)
Granted (in dollars per share)
Assets, Current [Abstract]
Current assets:
Grant percentage of target shares granted
Share-Based Compensation Arrangement By Share-Based Payment Award, Grant Percentage Of Target Shares Granted
Share-Based Compensation Arrangement By Share-Based Payment Award, Grant Percentage Of Target Shares Granted
Accounts Payable and Other Accrued Liabilities, Current
Accrued expenses and other current liabilities
Total
Amortization of Intangible Assets
Intangible assets amortization expense
Other Accounts Receivable, Related Parties, Current
Other Accounts Receivable, Related Parties, Current
Other accounts receivable from related party
Fair Value, Inputs, Level 3 [Member]
Level 3
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Long-Term Debt Including Finance Lease Liabilities
Long-term debt including finance lease liabilities.
Total debt
Liabilities, Fair Value Disclosure [Abstract]
Liabilities:
Current portion of long-term debt and finance lease obligations
Current portion of long-term debt and finance lease obligations
Long Term Debt and Finance Lease Liability Current
Long term debt and finance lease liability current.
Current portion of long-term debt and finance lease liabilities
Proceeds from tranche of term loans
Proceeds from Long-Term Lines of Credit
Total identifiable assets acquired
Business Combination, Recognized Asset Acquired, Asset
Property, plant and equipment, net
Deferred Tax Liabilities, Property, Plant and Equipment
Business Combinations
Business Combination [Policy Text Block]
Unrealized Gain (Loss) on Investments
Unrealized gains on marketable securities
Liabilities, Current [Abstract]
Current liabilities:
Restructuring and Related Activities Disclosure [Text Block]
Restructurings
Repurchases of common stock, value
Stock Repurchased and Retired During Period, Value
Other Current Liabilities [Table Text Block]
Schedule of Accrued Expenses and Other Current Liabilities
Pension and Other Post Retirement Benefits Plans, Net Prior Service Cost Credit
Pension and Other Post Retirement Benefits Plans, Net Prior Service Cost Credit [Roll Forward]
Prior Service Costs
Related Party Transactions [Abstract]
Operating loss carryforwards
Operating Loss Carryforwards
Trade accounts receivable, net
Accounts Receivable, after Allowance for Credit Loss, Current
Trade accounts receivable, net
Trade accounts receivable, net
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Schedule of Trade Accounts Receivable, Net
Indefinite-Lived Technology-Based Intangible Assets And Legacy Trademarks [Member]
Indefinite-Lived Technology-Based Intangible Assets And Legacy Trademarks
Indefinite-lived process technology and trademarks
Restricted Cash and Cash Equivalent
Restricted cash at end of period
Restricted cash at beginning of period
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Reclassification Adjustment, before Tax
Change in AOCI for non-U.S. defined benefit plan
Proceeds from issuance of common stock under employee purchase plan
Proceeds from Stock Plans
Commitments and Contingencies
Commitments and contingencies (Note 16)
Lessee, Leases [Policy Text Block]
Leases
Defined Benefit Plan, Service Cost
Service cost
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value
Ending balance (in dollars per share)
Beginning balance (in dollars per share)
Research And Development
Research And Development [Member]
Research and development.
Total lease liabilities
Operating Lease, Liability
Inventory, Work in Process, Net of Reserves
Work in process
Adjustments
Goodwill, Measurement Period Adjustment
Measurement period adjustments
Deferred Compensation Liability, Current
Accrued incentive programs
Auditor Firm ID
Auditor Firm ID
Debt Instrument, Basis Spread on Variable Rate
Basis spread on variable rate
Schedule of Goodwill [Table Text Block]
Summary of Changes in Carrying Amount of Goodwill
Restricted Cash, Current
Restricted cash
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Axis]
Restricted Cash and Cash Equivalents, Fair Value Disclosure
Restricted Cash and Cash Equivalents, Fair Value Disclosure
Money market fund deposits
Number Of Locations
Number Of Locations
Number of locations
Heyday
Heyday [Member]
Heyday
Current portion of long-term debt
Finance Lease, Liability, Current
Lessee, Lease, Description [Table]
Lessee, Lease, Description [Table]
Weighted-average discount rate - finance leases
Finance Lease, Weighted Average Discount Rate, Percent
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent
Changes in valuation allowances
Schedule of Anti Dilutive Securities Excluded
Schedule Of Anti Dilutive Securities Excluded
Schedule Of Anti Dilutive Securities Excluded [Table Text Block]
Weighted average useful life
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms
Weighted-Average Remaining Contractual Life (In years)
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]
Summary of Changes in Accrual for Employee Severance and Related Expenses
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]
Schedule of Amounts Recorded for AOCI for Defined Benefit Plan
Equity Method Investee [Member]
PSL
Property, plant and equipment purchases included in trade accounts payable and accrued expenses
Capital Expenditures Incurred but Not yet Paid
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Net (loss) income
Net (loss) income
AME Plan
AME Plan [Member]
AME Plan
Effective Income Tax Rate Reconciliation Nondeductible Loss On Forward Purchase Contract
Effective income tax rate reconciliation nondeductible loss on forward purchase contract.
Nondeductible - loss on forward repurchase contract
Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent
Cash
Accrued Income Taxes, Current
Accrued income taxes
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item
Other non-cash reconciling items
Additional direct funding and tax credits amount
Debt Instrument Additional Direct Funding And Tax Credits Amount
Debt instrument additional direct funding and tax credits amount.
Long-Term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]
Weighted Average Number of Shares Outstanding, Basic
Basic (in shares)
Basic weighted average common shares (in shares)
Goodwill, Acquired During Period
Acquisition
Revenue from External Customers by Geographic Areas [Table Text Block]
Revenue from External Customers by Geographic Areas
Gain (Loss) on Securities [Table Text Block]
Gain (Loss) on Securities
Credit Suisse AG, Cayman Islands Branch
Credit Suisse AG, Cayman Islands Branch [Member]
Credit Suisse AG, Cayman Islands Branch
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Change in plan assets:
Other
Other Stock [Member]
Other Stock
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Schedule of Income Taxes Reconciliation
Deferred Tax Liabilities, Leasing Arrangements
Right-of-use assets
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Deferred Tax Liabilities, Investment in Noncontrolled Affiliates
Equity method and other investments
Long-Lived Tangible Asset [Domain]
Long-Lived Tangible Asset [Domain]
Other Americas
Other Americas [Member]
Other Americas
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]
Total loans outstanding
Outstanding balance
Total loans outstanding
Related Party Transactions Disclosure [Text Block]
Related Party Transactions
Initial PSL Loan
Initial PSL Loan [Member]
Initial PSL Loan
Refinanced and Repricing 2023 Term Loan Facility
Refinanced And Repricing Two Thousand Twenty Three Term Loan Facility [Member]
Refinanced and repricing two thousand twenty three term loan facility.
Transaction costs
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Transaction Costs, Amount
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Transaction Costs, Amount
Effective Income Tax Rate Reconciliation, Refund Interest And Other
Effective income tax rate reconciliation, refund interest and other.
Refund interest and other
Variable Rate [Domain]
Variable Rate [Domain]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)
Actuarial loss
Actuarial (gain) loss
Changes in valuation allowances
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount
Defined Benefit Plan, Amortization of Transition Asset (Obligation)
Amortization of net transition asset
Stockholders' Equity Attributable to Parent
Equity attributable to Allegro MicroSystems, Inc.
Preferred Stock, Par or Stated Value Per Share
Preferred stock, par value (in dollars per share)
Industrial And Other End Market [Member]
Industrial and other end market.
Industrial and Other
Right-of-use asset
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Operating Lease, Right-of-Use Asset
Business combination, recognized identifiable assets acquired and liabilities assumed, assets, operating lease, right-of-use asset.
Redemptions
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Decrease for Settlement
Number Of Continents On Which Entity Operates
Number Of Continents On Which Entity Operates
Number of continents on which entity operates
Lessee, Operating Lease, Existence of Option to Extend [true false]
Statement of Stockholders' Equity [Abstract]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Shares Cancelled In Period Weighted Average Grant Date Fair Value
Share based compensation arrangement by share based payment award equity instruments other than options shares cancelled in period weighted average grant date fair value.
Cancelled (in dollars per share)
Equity Method Investments
Equity investment in related party
Type of Restructuring [Domain]
Other Liabilities Disclosure [Abstract]
Deferred Income Tax, Estimated Rate Benefit
Deferred Income Tax, Estimated Rate Benefit
Deferred income tax, estimated rate benefit
Use of Estimates, Policy [Policy Text Block]
Use of Estimates
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total
Property, plant and equipment
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Disclosure [Line Items]
Over-Allotment Option [Member]
Underwriters Option
Leasehold improvements
Leasehold Improvements [Member]
Foreign Currency Transaction Gain (Loss), before Tax
Foreign currency transaction (loss) gain
Fair Value Disclosures [Text Block]
Fair Value Measurements
Accounts Receivable, Returns, Credits Issued, And Price Protection Adjustments, Current
Accounts Receivable, Returns, Credits Issued, And Price Protection Adjustments, Current
Trade accounts receivable, returns, credits issued, and price protection adjustments, current
Increase (Decrease) in Net Income (Loss)
Increase (decrease) in net income (loss).
Increase (decrease) in net income (loss)
UNITED STATES
United States
Morgan Stanley Senior Funding, Inc
Morgan Stanley Senior Funding, Inc [Member]
Morgan Stanley Senior Funding, Inc
Noncontrolling Interest [Member]
Non-controlling Interests
Investment in debt security
Investment in Debt Security
Investment in debt security.
Payments For Taxes Related To Repurchase Of Common Stock
Payments for taxes related to repurchase of common stock.
Payments for taxes related to repurchase of common stock
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Other Liabilities Disclosure [Text Block]
Other Long-Term Liabilities
Income (Loss) from Equity Method Investments
(Loss) income in earnings of equity investment
Intangible Asset, Acquired, Finite-Lived [Line Items]
Acquired Finite-Lived Intangible Assets [Line Items]
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]
Schedule of Unrecognized Tax Benefits Roll Forward
Debt Instrument, Periodic Payment
Periodic payment
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]
Aggregate purchase price paid in cash
Payments for Merger Related Costs
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]
Schedule of ESPP Fair Value Assumptions
Net Proceeds From Issuance Of Secured Debt
Net proceeds from issuance of secured debt.
Net proceeds from 2026 Refinanced Term Loan Facility
Interest Expense, Operating and Nonoperating
Interest expense
Unrecognized Tax Benefits, Net
Unrecognized Tax Benefits, Net
Provision for uncertain tax positions
Trade Accounts Receivable, Net
Receivable [Policy Text Block]
Entity [Domain]
Entity [Domain]
Building [Member]
Buildings
Credit Facility [Axis]
Credit Facility [Axis]
Other Comprehensive Income (Loss), Defined Benefit Plan, Prior Service Cost (Credit), after Reclassification Adjustment, Tax
Other Comprehensive Income (Loss), Defined Benefit Plan, Prior Service Cost (Credit), after Reclassification Adjustment, Tax
Less tax expense
Cost of Product and Service Sold
Cost of goods sold
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Text Block]
Long-term Debt, And Finance Lease Liabilities Excluding Current Maturities
Long-term debt, and finance lease liabilities excluding current maturities.
Total long-term debt and finance lease liabilities, less current portion
Impairment, Long-Lived Asset, Held-for-Use
Impairment, Long-Lived Asset, Held-for-Use, Total
Impairment of long-lived assets
Current State and Local Tax Expense (Benefit)
State
Schedule of Expected Benefit Payments [Table Text Block]
Schedule of Estimated Future Benefit Payments
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]
Finance Lease, Liability, to be Paid, Year One
2027
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year
Company contributions next fiscal year
Operating Leases
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
Restructuring Plan [Axis]
Related Party [Axis]
Related Party [Axis]
Pension Plan [Member]
Pension Plan
Defined Benefit Plan
Property, Plant and Equipment, Policy [Policy Text Block]
Property, Plant and Equipment, Net
Accounting Standards Update [Extensible Enumeration]
Entity Address, City or Town
Entity Address, City or Town
Restructuring Reserve, Translation and Other Adjustment
Other
Stock Repurchased During Period, Shares
Repurchases of common stock
Repurchase of common stock
Long-Term Purchase Commitment, Period
Purchase commitment period
Other comprehensive income (loss).
Other Comprehensive Income (Loss) [policy Text Block]
Other Comprehensive (Loss) Income
Stock-based compensation, net of forfeitures and restricted stock vested
Stock Issued During Period Value Share Based Compensation And Restricted Stock Vested
Stock issued during period value share based compensation and restricted stock vested.
Security Exchange Name
Security Exchange Name
Credit Facility [Domain]
Credit Facility [Domain]
Europe [Member]
Europe
Total loans outstanding
Long-Term Debt, Gross
Property, Plant and Equipment, Gross
Total
Contingent Consideration, Fair Value Disclosure
Contingent Consideration, Fair Value Disclosure
Contingent consideration
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current:
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest
(Loss) income before income taxes
Concentration Risk Type [Domain]
Concentration Risk Type [Domain]
Completed technologies
Technology-Based Intangible Assets [Member]
Process technology
Finance Lease, Liability, to be Paid, Year Five
2031
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent
Foreign tax effects
Inventory, Net
Inventories
Total
Debt Instrument Loans and Commitments Terminate Percentage
Debt Instrument Loans and Commitments Terminate Percentage
Terminate percentage
Increase (Decrease) in Due to Related Parties
Increase (Decrease) in Due to Related Parties, Total
Payment to related party
Cash and cash equivalents and restricted cash at beginning of period
Cash and cash equivalents and restricted cash at end of period:
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation
Cash and cash equivalents and Restricted cash
Interest Paid, Excluding Capitalized Interest, Operating Activity
Cash paid for interest
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Statistical Measurement [Domain]
Statistical Measurement [Domain]
Assets, Current
Total current assets
Share-Based Payment Arrangement, Expense
Stock-based compensation
Document Period End Date
Document Period End Date
Other Comprehensive (Income) Loss, Defined Benefit Plan, Transition Asset (Obligation), After Reclassification Adjustment, Before Tax
Other Comprehensive (Income) Loss, Defined Benefit Plan, Transition Asset (Obligation), After Reclassification Adjustment, Before Tax
Net transition obligation
Other Asset Related Party
Other asset related party.
Related party - other asset
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV [Domain]
Defined Contribution Plan, Cost
Total contributions
ICFR Auditor Attestation Flag
ICFR Auditor Attestation Flag
Secondary PSL Loan
Secondary PSL Loan [Member]
Secondary PSL Loan
Commitment fee percentage
Line of Credit Facility, Commitment Fee Percentage
Defined Benefit Plan, Benefit Obligation, Benefits Paid
Benefits paid
Accrued Vacation, Current
Accrued vacation
Other Assets, Miscellaneous, Noncurrent
Other
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Tax
Ending balance
Beginning balance
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets
Plan assets
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]
Accrued Salaries, Current
Accrued salaries, wages and retirement benefits
Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life
Weighted average useful life
Statement of Financial Position [Abstract]
RSUs
Restricted Stock Units (RSUs) [Member]
Restricted Stock Units (RSUs)
Other Taxes Receivable Noncurrent
Other taxes receivable noncurrent.
Other taxes receivable long-term
Assets Identified no Longer Meeting Held for Sale
Assets identified no longer meeting held for sale.
Assets identified no longer meeting held for sale
Lessee, Operating Lease, Existence of Option to Terminate [true false]
Antidilutive Security, Excluded EPS Calculation [Table]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Buildings, Building Improvements And Leasehold Improvements
Buildings, Building Improvements And Leasehold Improvements [Member]
Buildings, building improvements and leasehold improvements
Reconciliation of cash and cash equivalents and restricted cash:
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract]
June 2025 Restructuring [Member]
June 2025 Restructuring.
June 2025 Restructuring
Refinanced and Repricing Two Thousand Twenty Five Term Loan Facility [Member]
Refinanced and repricing two thousand twenty five term loan facility.
Refinanced and Repricing 2025 Term Loan Facility
Effective Income Tax Rate Reconciliation, Cumulative Provision-To-Return, Amount
Effective Income Tax Rate Reconciliation, Cumulative Provision-To-Return, Amount
Cumulative provision-to-return
Related Party Revenue
Related Party Revenue [Member]
Related Party Revenue
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant
Employer contributions
Current Income Tax Expense (Benefit)
Total current
Refinanced Two Thousand And Twenty Three Term Loan Facility [Member]
Refinanced two thousand and twenty three term loan facility.
Refinanced 2023 Term Loan Facility
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Finance Leases
Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
Liabilities
Total liabilities
KOREA, REPUBLIC OF
South Korea
Restructuring Reserve, Settled without Cash
Non-cash adjustments
Majority Shareholder [Member]
Sanken
Equity Method Investments [Policy Text Block]
Equity-Method Investments
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount
Foreign tax effects/rate
Defined Benefit Plan, Expected Return (Loss) on Plan Assets
Expected return on plan assets
Lessee, Operating Lease, Liability, to be Paid, Year Two
2028
Restricted Stock [Member]
Restricted Common Stock
Finance Lease, Right-of-Use Asset, Amortization
Amortization of finance lease right-of-use assets
Variable Rate [Axis]
Variable Rate [Axis]
Finite-Lived Intangible Assets, Gross
Gross
Weighted Average Number of Shares Outstanding, Diluted
Diluted (in shares)
Diluted weighted average common shares (in shares)
Diluted weighted average common shares (in shares)
Entity File Number
Entity File Number
Other Assets
Advanced Payments Other Assets
Other Assets, Total
Related party - other assets
Cover [Abstract]
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Wafer Foundry Agreement, Mask Pricing Term
Wafer Foundry Agreement, Mask Pricing Term [Member]
Wafer Foundry Agreement, Mask Pricing Term
Accounts Receivable, before Allowance for Credit Loss, And Due From Related Parties, Current
Accounts Receivable, before Allowance for Credit Loss, And Due From Related Parties, Current
Trade accounts receivable
Total
Prepaid Expense and Other Assets, Current
Prepaid expenses and other current assets
Forfeited (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period
Wafer Foundry Agreement, Termination Notice Period
Wafer Foundry Agreement, Termination Notice Period [Member]
Wafer Foundry Agreement, Termination Notice Period
Increase Decrease In Due To From Related Party
Increase decrease in due to from related party.
Due to and from related party
Asset Intended to be Sold
Asset intended to be sold.
Asset intended to be sold
Revenue Benchmark [Member]
Revenue Benchmark
Number of Operating Segments
Number of operating segments
Sale of Stock [Domain]
Refinanced Two Thousand and Twenty Four Term Loan Facility [Member]
Refinanced two thousand and twenty four term loan facility.
Refinanced 2024 Term Loan Facility
Defined Benefit Plan, Plan with Projected Benefit Obligation in Excess of Plan Assets [Table Text Block]
Obligations and Asset Information for Plan with Projected Benefit Obligation in Excess of Plan Assets
Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table]
Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table]
Noncontrolling Interest [Line Items]
Noncontrolling Interest [Line Items]
Nonvested Restricted Stock Shares Activity [Table Text Block]
Summary of Unvested Restricted Common Stock Activity
Deferred Tax Assets, Other
Other accruals and reserves
Accounts payable
Accounts payable
Business Combination, Recognized Liability Assumed, Accounts Payable, Current
Finite-Lived Intangible Assets, Net
Net Carrying Amount
Gain (Loss) on Extinguishment of Debt
Loss on debt extinguishment
Loss on extinguishment of debt
Document Financial Statement Restatement Recovery Analysis [Flag]
Restructuring Charges
Total
Restructuring charges
Costs incurred
Property, Plant and Equipment, Useful Life
Useful Life
Average useful life of machinery and equipment
New Accounting Pronouncements, Policy [Policy Text Block]
Recent Accounting Pronouncements
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent
Other
Ownership [Axis]
Ownership [Axis]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period
Vesting period
Employee Severance
Employee Severance [Member]
Income (Loss) from Continuing Operations before Income Taxes, Domestic
Domestic operations
Depreciation
Depreciation expense
Net actuarial gain and amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Net actuarial gain (loss) on amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax
Net actuarial gain (loss) on amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax of $(359), $(84) and $145 in fiscal years 2026, 2025 and 2024, respectively
Other Receivables, Net, Current
Other Receivables, Net, Current, Total
Accounts receivable - other
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense
Unrecognized tax benefits, income tax penalties and interest expense
Lessee, Operating Lease, Term of Contract
Operating lease agreement term
Common Stock, Shares, Outstanding
Ending balance (in shares)
Beginning balance (in shares)
Common stock, shares outstanding (in shares)
Operating Lease, Liability, Current
Current portion of operating lease liabilities
Depreciation, Depletion and Amortization
Depreciation and amortization
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)
Amortization of prior service cost
Cybersecurity Risk Management Processes Integrated [Flag]
Document Transition Report
Document Transition Report
Deferred Tax Assets, Net
Deferred income tax assets
Operating Expenses
Total operating expenses
Research and Development Expense
Research and development
Payments for Repurchase of Common Stock
Repurchases of common stock
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Schedule of Significant Components of Income Taxes (Benefit) Provision
Comprehensive income
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Comprehensive (loss) income
Statement of Cash Flows [Abstract]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-Average Grant-Date Fair Value
Current Federal Tax Expense (Benefit)
Federal
Stock Issued During Period, Value, New Issues
Issuance of common stock
Issuance of common stock, net of underwriting discounts
Assets, Fair Value Disclosure [Abstract]
Assets:
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-Based Payment Arrangement, Percent
Stock-based compensation
Payments to Acquire Businesses, Net of Cash Acquired
Acquisition of business, net of cash acquired and working capital adjustment
Accounts and Financing Receivables [Table]
Bank Loan Obligations [Member]
Loans
Inventory, Raw Materials and Supplies, Net of Reserves
Raw materials and supplies
Effective Income Tax Rate Reconciliation, Officer Compensation, Percent
Effective Income Tax Rate Reconciliation, Officer Compensation, Percent
162(m) limitation
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets [Line Items]
Earnings Per Share [Text Block]
Net (Loss) Income per Share
Impairment on Assets Held for Sale
impairment on assets held for sale.
Impairment on assets held for sale
Unrecognized Tax Benefits that Would Impact Effective Tax Rate
Unrecognized tax benefits that would impact effective tax rate
Cybersecurity Risk Management Processes Integrated [Text Block]
Net (loss) income attributable to Allegro MicroSystems, Inc.
Net (loss) attributable to Allegro MicroSystems, Inc.
Inventory Write-down
Recorded inventory provisions
Increase (Decrease) in Inventories
Inventories
Accrued expenses and other current liabilities
Accrued expenses and other current liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Accrued Expenses and Other Current Liabilities
Business combination, recognized identifiable assets acquired and liabilities assumed, current liabilities accrued expenses and other current liabilities.
Pension and Other Postretirement Plans, Pensions, Policy [Policy Text Block]
Pension and Other Postretirement Benefit Obligations
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax
Ending balance
Beginning balance
Balance, net of tax
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Issued in Period, Weighted Average Grant Date Fair Value
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Issued in Period, Weighted Average Grant Date Fair Value
Issued (in dollars per share)
Operating Lease, Cost
Operating lease expense
Income Tax Contingency [Line Items]
Income Tax Contingency [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)
Unrealized gains on marketable securities
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting date
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate
Dividend yield
Intangible Assets, Net (Excluding Goodwill)
Intangible assets, net
Net Carrying Amount
Line of Credit Facility [Line Items]
Line of Credit Facility [Line Items]
Dividends paid to non-controlling interest
Payments of Ordinary Dividends, Noncontrolling Interest
Operating Lease, Payments
Cash paid for operating leases
Effective Income Tax Rate Reconciliation, FDII, Percent
Foreign-derived intangible income benefit
Foreign-derived intangible income benefit
Assets [Abstract]
Assets
Income Tax Authority, Name [Axis]
Income Tax Authority, Name [Axis]
Other Asia
Other Asia [Member]
Other Asia
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate
Risk-free rate of return
Construction in Progress [Member]
Construction in progress
Increase (Decrease) in Prepaid Expense and Other Assets
Prepaid expenses and other assets
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit
Actuarial loss
Restructuring and Related Activities [Abstract]
Nondeductible - loss on forward repurchase contract
Effective Income Tax Rate Reconciliation Nondeductible Loss on Forward Repurchase Contract
Effective income tax rate reconciliation nondeductible loss on forward repurchase contract.
Document Fiscal Year Focus
Document Fiscal Year Focus
Concentration Risk Benchmark [Domain]
Concentration Risk Benchmark [Domain]
Accrued severance
Accrued Severance Current
Accrued severance current.
Cash flows from investing activities:
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]
Retirement Benefits [Abstract]
Amounts due to related party
Accounts Payable, Current
Accounts Payable, Current, Total
Provisions for inventory and expected credit losses
Inventory Write-Down And Accounts Receivable, Credit Loss Expense (Reversal)
Inventory Write-Down And Accounts Receivable, Credit Loss Expense (Reversal)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations
Gross decreases lapse of applicable statutes of limitations
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]
Schedule of Components of (Loss) Income before Income Taxes
Research and Development Expense [Member]
Research and development
Research and Development
Schedule of Net Benefit Costs [Table Text Block]
Schedule of Expense Related to Defined Benefit Plan
Deferred Federal Income Tax Expense (Benefit)
Federal
Schedule of Changes in Fair Value of Plan Assets [Table Text Block]
Schedule of Changes in Fair Value of Level 3 Plan Assets
Net gains and losses recognized during the period on equity securities
Equity Securities, FV-NI, Gain (Loss)
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]
Non-Controlling Interests
Restructuring Cost and Reserve [Line Items]
Finite-Lived Intangible Asset, Expected Amortization, Year One
2027
Property, Plant and Equipment, Disposals
Fully depreciated assets retired during period
Deferred Income Tax, Estimated Rate Benefit Current
Deferred income tax, estimated rate benefit current.
Deferred income tax, estimated rate benefit current
Defined Benefit Plan, Debt Security [Member]
Loans
Purchase Obligation, to be Paid, Year One
Purchase obligation
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, Tax
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, Tax
Less tax expense
Amortization rate per quarter
Debt Instrument Amortization Rate
Debt instrument amortization rate.
Schedule of Other Assets [Table Text Block]
Schedule of Other Assets, Net
Less
Less [Abstract]
Less:
Unrecognized Tax Benefits [Roll Forward]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Asset, Held-for-Sale, Not Part of Disposal Group
Asset, Held-for-Sale, Not Part of Disposal Group, Total
Value of assets
Non-U.S. rate of compensation increases
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase
Fair Value Disclosures [Abstract]
Polar Semiconductor, LLC
Polar Semiconductor, LLC [Member]
Polar Semiconductor, LLC
Commitments and Contingencies Disclosure [Abstract]
Lessee, Operating Lease, Liability, to be Paid, Year One
2027
Repayments of term loan facility
Repayments of Long-Term Lines of Credit
Repayment of 2020 Term Loan Facility
Repayment of term loan
Sale of Stock, Consideration Received on Transaction
Net proceeds
Standard Product Warranty, Policy [Policy Text Block]
Product Warranties
Total identifiable net assets
Total identifiable net assets
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)
Effective Income Tax Rate Reconciliation Foreign Base and GILTI Income Amount
Effective income tax rate reconciliation foreign base and GILTI income amount.
Subpart F, GILTI and other inclusions, net of foreign tax credits
Long-Term Line of Credit
Outstanding balance
Debt Instrument [Axis]
Debt Instrument [Axis]
Thereafter
Lessee, Operating Lease, Liability, to be Paid, after Year Five
Defined Benefit Plan, Interest Cost
Interest cost
Share-Based Payment Arrangement [Abstract]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
Stock-based compensation expense not yet recorded
Assets, Fair Value Disclosure
Total assets
Deferred Tax Liabilities, Intangible Assets
Intangibles assets, net
Refinanced Term Loan Facility [Member]
Refinanced Term Loan Facility.
Refinanced Term Loan Facility
Sale of Stock [Axis]
Deferred income tax liabilities
Business Combination, Recognized Liability Assumed, Deferred Tax Liability
Concentration Risk, Percentage
Concentration risk, percentage
Defined Benefit Plan, Expected Future Benefit Payment, Year One
2027
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]
Schedule of Restricted Stock Units Activity
January 2025 Restructuring
January 2025 Restructuring [Member]
January 2025 Restructuring.
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation
Net cash used in investing activities
Value Added Tax Receivable, Noncurrent
VAT receivables long-term
Loss On Change In Fair Value Of Forward Repurchase Contract
Loss on change in fair value of forward repurchase contract.
Loss on change in fair value of forward repurchase contract
Weighted-average remaining lease term - finance leases
Finance Lease, Weighted Average Remaining Lease Term
Title of 12(b) Security
Title of 12(b) Security
Trademarks And Other
Trademarks And Other [Member]
Trademarks and other
Fed Fund Rate
Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-Based Payment Arrangement, Amount
Stock-based compensation
Exchange for equity interests amounts of transaction
Exchange for Equity Interests Amounts of Transaction
Exchange for equity interests amounts of transaction.
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Transition Asset (Obligation), before Tax
Amounts in AOCI before tax
Forfeited (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value
Money Market Funds [Member]
Money Market Funds
Related Party [Domain]
Related Party [Domain]
Income Tax Disclosure [Text Block]
Income Taxes
Defined Contribution Plan, Age
Defined Contribution Plan, Age
Defined contribution plan, age
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Excess Shares Issued in Period, Weighted Average Grant Date Fair Value
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Excess Shares Issued in Period, Weighted Average Grant Date Fair Value
Excess shares issued due to achievement of performance condition (in dollars per share)
Patents [Member]
Patents
Other Liabilities, Noncurrent
Other long-term liabilities
Total
Restructuring Plan [Domain]
Finance Lease, Right-of-Use Asset, after Accumulated Amortization
Finance Lease, Right-of-Use Asset, after Accumulated Amortization, Total
Property, plant and equipment, net
Legal Entity [Axis]
Legal Entity [Axis]
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]
Changes in operating assets and liabilities:
Property, Plant and Equipment [Table Text Block]
Schedule of Property, Plant, and Equipment
Schedule of Estimated Useful Lives of Property, Plant, and Equipment
Defined Benefit Plan, Plan Assets, Amount
Fair value of plan assets at end of year
Fair value of plan assets at beginning of year
Assets of non-U.S. defined benefit plan
Income Tax Disclosure [Abstract]
Business Combinations
Business Combination [Text Block]
Unrecognized Tax Benefits
Beginning balance
Provision for uncertain tax positions
Ending balance
Additional Paid-in Capital [Member]
Additional Paid-In Capital
Decrease in Depreciation Expenses
Decrease in depreciation expenses
Decrease in depreciation expense
Decrease in depreciation expense
Measurement Frequency [Domain]
Measurement Frequency [Domain]
Statement of Income Location, Balance [Axis]
Income Statement Location [Axis]
Change in Accounting Principle, Accounting Standards Update, Adoption Date
Trading Symbol
Trading Symbol
Intangible Asset, Finite-Lived [Table]
Schedule of Finite-Lived Intangible Assets [Table]
Property, Plant and Equipment Disclosure [Text Block]
Property, Plant and Equipment, Net
Related Party Transaction [Table]
Schedule of Related Party Transactions, by Related Party [Table]
Subsequent Event Type [Axis]
2023 Term Loan Facility
2023 term loan facility
Two Thousand Twenty Three Term Loan Facility [Member]
Two thousand twenty three term loan facility.
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Schedule of Intangible Assets, Net
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation
Accumulated benefit obligations
TAIWAN
Taiwan
Cash flows from financing activities:
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Related Party Transaction, Purchases from Related Party
Purchases from related party
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term
Performance term
Fair Value, Recurring [Member]
Fair Value, Recurring
Entity Ex Transition Period
Entity Ex Transition Period
Lessee, Operating Lease, Liability, to be Paid
Total lease payments
Lessee, Operating Lease, Liability, Undiscounted Excess Amount
Less: imputed interest
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent
R&D credits
R&D credits
Marketable Securities Changes in Fair Value
Marketable Securities Changes in Fair Value
Change in fair value of marketable securities
Equity Components [Axis]
Equity Components [Axis]
PSL Promissory Notes [Member]
PSL Promissory Notes
PSL Promissory Notes
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation and funded status of plan:
Equity Component [Domain]
Equity Component [Domain]
Stock-based compensation, net of forfeitures and restricted stock vested (in shares)
Stock Issued During Period Shares Share Based Compensation And Restricted Stock Vested
Stock issued during period shares share based compensation and restricted stock vested.
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Preliminary and Final Purchase Price Allocation
Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block]
Document Annual Report
Document Annual Report
One- Month Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
One- Month Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
One- Month SOFR
Business Combination [Axis]
Business Acquisition [Axis]
Proceeds from Income Tax Refunds
Net income taxes refunded
Non-U.S. rate of compensation increases
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase
Machinery and Equipment [Member]
Machinery and equipment
Stock Issued During Period, Shares, Employee Stock Purchase Plans
Employee stock purchase plan issuances (shares)
Customer [Axis]
Customer [Axis]
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]
US Treasury and Government [Member]
Government securities
Other long-term liabilities
Other long-term liabilities
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liabilities, Other
Business combination, recognized identifiable assets acquired and liabilities assumed, liabilities, other.
Effective Income Tax Rate Reconciliation, Tax Contingency, Amount
Provision for uncertain tax positions
Effective Income Tax Rate Reconciliation, Tax Contingency, Amount, Total
Statement of Comprehensive Income [Abstract]
Maximum [Member]
Maximum
Liabilities, Fair Value Disclosure
Total liabilities
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Effective Income Tax Rate Reconciliation Foreign Base and GILTI Income Percent
Effective income tax rate reconciliation foreign base and GILTI income percent.
Subpart F, GILTI and other inclusions, net of foreign tax credits
Accumulated Amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Accumulated Amortization
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)
Change in foreign currency exchange rates
Foreign currency exchange rate changes
Common Stock, Value, Issued
Common stock, $0.01 par value; 1,000,000,000 shares authorized, 185,357,343 shares issued and outstanding at March 27, 2026; 1,000,000,000 shares authorized, 184,286,567 issued and outstanding at March 28, 2025
Finance lease payments
Finance Lease, Principal Payments
Principles of Consolidation
Consolidation, Policy [Policy Text Block]
Goodwill [Roll Forward]
Goodwill [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
Ending balance
Beginning balance
Total stockholders' equity
Two Thousand Twenty Four Term Loan Facility [Member]
Two thousand twenty four term loan facility.
2024 Term Loans
Income Tax Contingency [Table]
Income Tax Contingency [Table]
Related party transaction amounts
Related Party Transaction, Amounts of Transaction
Sales return of resalable inventory
Deferred Tax Assets, Operating Loss Carryforwards
NOL carryforwards
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]
Tax Credit Carryforward [Axis]
Tax Credit Carryforward [Axis]
Gain (Loss) on Sale of Derivatives
Loss on change in fair value of forward repurchase contract
Recognized loss of fair value forward repurchase contract
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]
Impairment of Long-Lived Assets
Effective Income Tax Rate Reconciliation, BEAT, Amount
BEAT alternative minimum tax
Schedule of Issuable Weighted Average Share Information
Schedule of Weighted Average Number of Shares [Table Text Block]
Additions
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase for Purchase
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent
State and local income tax, net of federal income tax effect
Amortization of Debt Issuance Costs
Amortization of deferred financing costs
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Schedule of Annual Amortization Expense
Wafer Foundry Agreement, Binding Years
Wafer Foundry Agreement, Binding Years [Member]
Wafer Foundry Agreement, Binding Years
Entity Public Float
Entity Public Float
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate
Volatility
Preferred Stock, Shares Authorized
Preferred stock, shares authorized (in shares)
Related Party Transaction, Terms of Consulting Agreement
Related Party Transaction, Terms of Consulting Agreement
Terms of consulting agreement
Interest Payable, Current
Accrued interest
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Other comprehensive gain (loss) attributable to non-controlling interests
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Payment, Tax Withholding, Share-Based Payment Arrangement
Payments for taxes related to net share settlement of equity awards
Lender Name [Axis]
Lender Name [Axis]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Phantom stock
Phantom Share Units (PSUs) [Member]
Phantom Share Units (PSUs)
Related Party Transaction [Line Items]
Related Party Transaction [Line Items]
Employee Stock [Member]
Employee Stock Purchase Plan (ESPP)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenue from Contract with Customer [Text Block]
Revenue from Contracts with Customers
Business Combination [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Entity Registrant Name
Entity Registrant Name
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued
Unrecognized tax benefits, income tax penalties and interest accrued
Debt Disclosure [Text Block]
Debt and Other Borrowings
Entity Voluntary Filers
Entity Voluntary Filers
Customer Concentration Risk [Member]
Customer Concentration Risk
Finite-Lived Intangible Asset, Expected Amortization, Year Two
2028
Other Nonoperating Income (Expense)
Other, net
Other income (expense), net
Additional Paid in Capital
Additional paid-in capital
Deferred State and Local Income Tax Expense (Benefit)
State
Other Assets Disclosure [Text Block]
Other Assets, Net
Cybersecurity Risk Management Positions or Committees Responsible [Flag]
SOFR
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Finite-Lived Intangible Asset, Expected Amortization, Year Three
2029
Income Tax Expense (Benefit)
Income tax provision (benefit)
Total income tax (benefit) provision
Income tax (benefit) provision
Income tax (benefit) provision
Payments for Intangible Assets
Payments for intangible assets
Payments for intangible assets
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Defined Benefit Plan, Expected Future Benefit Payment, After Year Five
Defined Benefit Plan, Expected Future Benefit Payment, After Year Five
Total 5 years thereafter
Defined Benefit Plan, Expected Future Benefit Payment, Year Five
2031
Stock Repurchased During Period, Value
Repurchase of Class A and Class L common stock to cover related taxes
Repurchases of common stock, value
Repurchase of common stock aggregate consideration , value
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Still Held
Revaluation of debt and equity securities
Net proceeds from issuance of common stock
Proceeds from Issuance of Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners
Noncontrolling interest ownership percentage
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding (in shares)
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Concentrations of Credit Risk and Significant Customers
Lease liability
Lease liability
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Operating Lease Liability
Business combination, recognized identifiable assets acquired and liabilities assumed, liabilities, operating lease liability.
Unit Investment Trust Fund
Unit Investment Trust Fund [Member]
Unit investment trust fund
Share-Based Compensation Arrangement By Share-Based Payment Award, Stock Plan, Offering Period
Share-Based Compensation Arrangement By Share-Based Payment Award, Stock Plan, Offering Period
Offering period
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated other comprehensive loss
Defined Benefit Plan, Equity Securities, Common Stock [Member]
Stocks
Payments for Restructuring
Cash disbursements
Payments to Acquire Property, Plant, and Equipment
Purchases of property, plant and equipment
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period
Granted (in shares)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax
Change in ACOI for non-U.S. defined benefit plan
Assets
Total assets
Inventory, Policy [Policy Text Block]
Inventories
Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Income Tax Paid, State and Local, after Refund Received
Income Tax Paid, State and Local, after Refund Received, Total
Net state payments
IncomeTaxPaidStateAndLocalAfterRefundReceived
Income Statement [Abstract]
Retirement Plan Name [Domain]
Retirement Plan Name [Domain]
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation
Accrued bonuses, sales commissions and other compensation
Restructuring Cost [Table]
Effective Income Tax Rate Reconciliation, Cross-Border, Other, Percent
Other
Fair Value of Financial Instruments, Policy [Policy Text Block]
Fair Value of Financial Instruments
Share-Based Payment Arrangement [Policy Text Block]
Stock-Based Compensation
Deferred income taxes
Total deferred
Deferred Income Tax Expense (Benefit)
Selling, General and Administrative Expenses [Member]
Selling, general and administrative
Selling, General and Administrative
Sale of Stock, Number of Shares Issued in Transaction
Number of shares issued in transaction (in shares)
Stock Issued During Period, Shares, New Issues
Issuance of common stock, net of underwriting discounts (in shares)
Issuance of common stock
Business Combination [Abstract]
Business Combinations [Abstract]
Long-term debt
Long-term debt
Business Combination, Recognized Liability Assumed, Long-Term Debt, Current
2020 Term Loan Facility
2020 term loan facility
Two Thousand Twenty Term Loan Facility [Member]
Two thousand twenty term loan facility.
Earnings Per Share, Diluted, Total
Diluted (in dollars per share)
Diluted net income attributable to Allegro MicroSystems, Inc. per share (in dollars per share)
Diluted net (loss) income per common share attributable to Allegro MicroSystems, Inc. stockholders
Finite-Lived Intangible Asset, Expected Amortization, Year Five
2031
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Trade accounts payable
Increase (Decrease) in Accounts Payable, Trade
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]
City Area Code
City Area Code
Auditor Name
Auditor Name
Debt Instrument, Fee Amount
Incurred fees amount
Long-term debt
Finance Lease, Liability, Noncurrent
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax
Amounts in AOCI before tax
Amounts in AOCI before tax
Debt Instrument, Face Amount
Principal amount
Crocus Technologies
Equity Method Investee 1 [Member]
Equity method investee 1.
Line of Credit Facility, Maximum Borrowing Capacity
Maximum borrowing capacity
Business Combination [Line Items]
Business Acquisition [Line Items]
Deferred Income Taxes and Other Assets [Abstract]
Deferred income tax assets:
Defined Benefit Plan [Table]
Schedule of Defined Benefit Plans Disclosures [Table]
Deferred Tax Assets, Tax Credit Carryforwards
Tax credits
Increase (Decrease) in Net Income (Loss) Per Share
Increase (decrease) in net income (loss) per share.
Increase (decrease) in net income (loss) per share
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount
Research and development tax credit
Business Exit Costs
Exit Cost
Proceeds from Income Tax Refund, Federal
Federal refund
Stock Issued During Period, Value, Employee Stock Purchase Plan
Employee stock purchase plan issuances
Power Integrated Circuits
Power Integrated Circuits [Member]
Power integrated circuits
Dividends, Cash
Dividends to non-controlling interest
Operating Lease, Weighted Average Remaining Lease Term
Weighted-average remaining lease term – operating leases
Related party notes receivable, less current portion
Nontrade Receivables, Noncurrent
Nontrade Receivables, Noncurrent, Total
Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block]
Changes in Benefit Obligations and Plan Assets
Retirement Plan Name [Axis]
Retirement Plan Name [Axis]
Letter of Credit
Letter of Credit [Member]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Cash and Cash Equivalents, Policy [Policy Text Block]
Cash Equivalents and Restricted Cash
Payments to Term Loan
Payments to term loan.
Payment applied to the term loan balance
Property, plant and equipment
Property, Plant and Equipment, Net
Property, plant and equipment, net
Total
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]
Goodwill
Defined Benefit Plan, Expected Future Benefit Payment, Year Three
2029
Deferred Foreign Income Tax Expense (Benefit)
Foreign
Impairment of intangible assets, net
Impairment of Intangible Assets, Finite-Lived
Corporate Bond Securities [Member]
Bonds
Initial Crocus Loan
Initial Crocus Loan [Member]
Initial crocus loan.
Operating Income (Loss)
Operating income (loss)
Goodwill, Foreign Currency Translation, Gain (Loss)
Foreign currency translation
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate
Non-U.S. assumed discount rate
Retained Earnings [Member]
Retained Earnings (Accumulated Deficit)
Cash and Cash Equivalents [Axis]
Cash and Cash Equivalents [Axis]
Share-Based Payment Arrangement, Noncash Expense
Stock-based compensation
Payments of Stock Issuance Costs
Stock issuance costs
Weighted Average Remaining Lease Term
Weighted Average Remaining Lease Term [Abstract]
Other information:
Real estate actions expenses
Real Estate Actions Expenses
Real estate actions expenses.
Operating Lease, Weighted Average Discount Rate, Percent
Weighted-average discount rate – operating leases
Operating Lease, Liability, Noncurrent
Operating lease liabilities, less current portion
Fair Value, Inputs, Level 1 [Member]
Level 1
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation
Net cash (used in) provided by financing activities
Lease, Cost [Table Text Block]
Lease, Cost
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent [Abstract]
Nontaxable or nondeductible items:
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]
Auditor Location
Auditor Location
Voxtel, Inc.
Voxtel, Inc. [Member]
Voxtel
Deferred Tax Assets, Leasing Arrangements
Deferred Tax Assets, Leasing Arrangements
Lease liabilities
Effective Income Tax Rate Reconciliation, FDII, Amount
Foreign-derived intangible income benefit
Deposits Assets, Noncurrent
Deposits
Investments, Fair Value Disclosure
Investment in debt security
Investments, Fair Value Disclosure, Total
Leases
Leases Disclosure [Text Block]
Leases disclosure.
Schedule of Prepaid Expenses and Other Current Assets
Schedule of Other Current Assets [Table Text Block]
Nonoperating Income (Expense) [Abstract]
Other (expense) income:
Accrual for Environmental Loss Contingencies
Environmental accruals
Accounts receivable
Business Combination, Recognized Asset Acquired, Receivable, Current
Magnetic Sensors
Magnetic Sensors [Member]
Magnetic sensors
Non-US [Member]
Non-US
Weighted Average Number Issuable Shares Outstanding Adjustment
Weighted Average Number Issuable Shares Outstanding Adjustment
Dilutive effect of common stock equivalents (in shares)
Income Tax Jurisdiction [Domain]
Entity Interactive Data Current
Entity Interactive Data Current
Defined Benefit Plan, Plan Assets, Category [Axis]
Defined Benefit Plan, Plan Assets, Category [Axis]
Defined Benefit Plan, Plan Assets, Category [Table Text Block]
Fair Value of Entity's Plan Assets
Statement of Income Location, Balance [Domain]
Income Statement Location [Domain]
Costs and Expenses, Related Party
Cost of goods sold to related party
Cash flows from operating activities:
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]
Defined Contribution Plan, Minimum Years Of Service
Defined Contribution Plan, Minimum Years Of Service
Years of service
Receipts on related party notes receivable
Proceeds from Related Party Debt
Loans made to related party
Wafer Foundry Agreement, Renewal Term
Wafer Foundry Agreement, Renewal Term [Member]
Wafer Foundry Agreement, Renewal Term
Contract with Customer, Asset, after Allowance for Credit Loss
Contract assets
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings
Change in fair value of contingent consideration
Share-Based Payment Arrangement, Expense, Tax Benefit
Income tax benefit
Income tax benefit
Entity Tax Identification Number
Entity Tax Identification Number
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity:
Land [Member]
Land
Share Price
Weighted-average fair value per share (in dollars per share)
Share price
Prepaid income taxes
Prepaid Taxes
Long-Term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Debt Instrument, Term
Term
Effective Income Tax Rate Reconciliation, Changes in Unrecognized Tax Benefits, Percent
Effective income tax rate reconciliation, changes in unrecognized tax benefits, percent.
Changes in unrecognized tax benefits
Changes in unrecognized tax benefits
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Nature of the Business and Basis of Presentation
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]
Trade Accounts Receivable, Net
Income Tax Authority, Name [Domain]
Income Tax Authority, Name [Domain]
Effect of exchange rate changes on cash and cash equivalents and restricted cash
Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation
Interest Income, Other
Interest income
Defined Benefit Plan, Expected Future Benefit Payment, Total
Defined Benefit Plan, Expected Future Benefit Payment, Total
Total
Local Phone Number
Local Phone Number
Related Party Transaction [Domain]
Related Party Transaction [Domain]
Finance leases
Finance Lease, Assets And Liabilities, Lessee [Abstract]
Finance lease, assets and liabilities, lessee.
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Net periodic pension expense
Completed technology
Completed Technology [Member]
Completed technology.
Automotive End Market
Automotive End Market [Member]
Automotive
Short-Term Lease, Cost
Short term lease expense
CHINA
Greater China
Auditor Opinion
Auditor Opinion [Text Block]
Restructuring Costs
Total
Restructuring costs
AML US Employee, Defined Contribution Plan
AML US Employee, Defined Contribution Plan [Member]
AML US Employee, Defined Contribution Plan
Finance Lease, Liability, to be Paid, Year Two
2028
Long-Lived Assets
Total
Financing Receivable, Current, Allowance for Credit Loss [Table Text Block]
Schedule of Changes in Allowance for Doubtful Accounts and Returns and Sales Allowances
Weighted Average Number of Shares Outstanding, Basic [Abstract]
Weighted average shares outstanding:
Accounting Policies [Abstract]
Sanken Distribution Agreement, One-Time Sales Return
Sanken Distribution Agreement, One-Time Sales Return [Member]
Sanken Distribution Agreement, One-Time Sales Return
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Other Sundry Liabilities, Current
Other
Revenue from Contract with Customer, Excluding Assessed Tax
Total net sales
Net sales
Lessee, Operating Lease, Liability, to be Paid, Year Four
2030
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant
Number of shares immediately available for grant (in shares)
Weighted average useful life
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition
Office Equipment [Member]
Office equipment
Accrued Professional Fees, Current
Accrued professional fees
Right-of-use asset
Right Of Use Asset [Member]
Right Of Use Asset.
Entity Emerging Growth Company
Entity Emerging Growth Company
Deferred Tax Assets, Capitalized Research And Development Costs
Deferred Tax Assets, Capitalized Research And Development Costs
Capitalized research and development costs
Tax Credit Carryforward, Name [Domain]