Document And Entity Information
Dividend yield
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate
Fair Value of Financial Instruments, Policy [Policy Text Block]
Note To Financial Statement Details Textual
Significant Accounting Policies
Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
2021
nvec_IncomeTaxReconciliationDeductionForeignDerivedIntangibleIncome
Foreign-derived intangible income deduction
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for foreign-derived intangible income.
Note 2 - Summary of Significant Accounting Policies
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
2022
Tax expense at U.S. Statutory rate
Note 3 - Fair Value of Financial Instruments
Total
Risk-free interest rate
Note 4 - Inventories
Less than 1 year
Note 5 - Stock-based Compensation
Note 6 - Income Taxes
Note 7 - Leases
Note 8 - Concentrations
Note 2 - Summary of Significant Accounting Policies - Weighted Average Number of Shares (Details)
Income Tax Disclosure [Text Block]
Note 3 - Fair Value of Financial Instruments - Fair Value of Available-for-sale Securities (Details)
Unrealized gain on marketable securities, net of tax
Unrealized gain from marketable securities, net of tax
Note 3 - Fair Value of Financial Instruments - Assets Measured on Recurring Basis (Details)
Note 3 - Fair Value of Financial Instruments - Reconciliation of Available-for-sale Securities (Details)
Lessee, Operating Lease, Liability, Maturity [Table Text Block]
us-gaap_ShareBasedCompensation
Stock-based compensation
Expected volatility
Note 3 - Fair Value of Financial Instruments - Investment Securities With Unrealized Losses (Details)
us-gaap_LiabilitiesCurrent
Total current liabilities
Note 4 - Inventories - Summary of Inventories (Details)
Note 5 - Stock-based Compensation - Schedule of Valuation Assumptions (Details)
Note 5 - Stock-based Compensation - Summary of Options Outstanding (Details)
Note 5 - Stock-based Compensation - Summary of Stock Options (Details)
Note 6 - Income Taxes - Schedule of Income Tax Provisions (Details)
Expected life (years) (Year)
Earnings Per Share, Policy [Policy Text Block]
Note 6 - Income Taxes - Reconciliation of Income Tax Provisions (Details)
Note 6 - Income Taxes - Deferred Tax Assets and Liabilities (Details)
Note 7 - Leases - Operating Lease (Details)
Note 7 - Leases - Maturities of Lease Liabilities (Details)
Note 8 - Concentrations - Revenue by Major Customers (Details)
us-gaap_Revenues
Revenue
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Notes To Financial Statements
Notes To Financial Statements [Abstract]
nvec_AvailableForSaleDebtSecuritiesRemainingMaturity
Available for Sale Debt Securities, Remaining Maturity (Month)
The remaining maturity of available for sale debt securities.
Income Tax, Policy [Policy Text Block]
nvec_AvailableForSaleDebtSecurititesPercentOfTotalAssets
Available for Sale Debt Securitites, Percent of Total Assets
The amount of available for sale debt securities as a percentage of total assets.
Share-based Payment Arrangement, Activity [Table Text Block]
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Gross unrealized losses, 12 months or greater
Proceeds from maturities and sales of marketable securities
us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Total gross unrealized losses
us-gaap_LesseeOperatingLeaseRenewalTerm
Lessee, Operating Lease, Renewal Term (Month)
Research and Development Expense, Policy [Policy Text Block]
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Gross unrealized losses, less than 12 months
Marketable securities, long-term
Depreciation and amortization
us-gaap_AssetsCurrent
Total current assets
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)
Share-based Payment Arrangement [Policy Text Block]
Total fair market value
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value
Fair market value, less than 12 months
Fair market value, 12 months or greater
Common stock, $0.01 par value, 6,000,000 shares authorized; 4,835,038 issued and outstanding as of March 31, 2020 and 4,846,010 as of March 31, 2019
us-gaap_PaymentsToAcquireMarketableSecurities
Purchases of marketable securities
Adjustments to reconcile net income to net cash provided by operating activities:
Measurement Frequency [Axis]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted average option exercise price (in dollars per share)
Measurement Frequency [Domain]
Fair Value, Recurring [Member]
Common stock, shares authorized (in shares)
Common stock, shares issued (in shares)
Discount rate
Common stock, par value (in dollars per share)
us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Granted, weighted average option exercise price (in dollars per share)
Revenue from Contract with Customer [Policy Text Block]
nvec_NumberOfOtherThanTemporarilyImpairedMarketableSecurities
Number of Other-than-temporarily Impaired Marketable Securities
Represents the number of marketable securities the company considers other-than-temporarily impaired.
us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
Exercised, weighted average option exercise price (in dollars per share)
Standard Product Warranty, Policy [Policy Text Block]
Accrued payroll and other
Statistical Measurement [Domain]
Operating cash flows for leases
Maximum [Member]
Minimum [Member]
Lessee, Operating Leases [Text Block]
Accounts payable
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Option shares reserved (in shares)
Product and Service [Axis]
us-gaap_DeferredTaxAssetsNet
Deferred tax assets
Product and Service [Domain]
Statistical Measurement [Axis]
us-gaap_PolicyTextBlockAbstract
Accounting Policies
Cash paid during the year for income taxes
us-gaap_DeferredTaxAssetsOther
Other
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]
Inventories
Total inventories
us-gaap_DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross
Unrealized (gain) loss on marketable securities
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchases of fixed assets
Dilutive effect of stock options (in shares)
Fair Value Hierarchy and NAV [Domain]
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)
Inventory reserve
Customer [Axis]
Fair Value, Inputs, Level 1 [Member]
Customer [Domain]
Fair Value, Inputs, Level 2 [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)
Fair Value Hierarchy and NAV [Axis]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Product [Member]
us-gaap_Assets
Total assets
Supplemental disclosures of cash flow information:
Cumulative Effect, Period of Adoption [Domain]
Cumulative Effect, Period of Adoption [Axis]
us-gaap_PropertyPlantAndEquipmentUsefulLife
Property, Plant and Equipment, Useful Life (Year)
Cumulative Effect, Period of Adoption, Adjustment [Member]
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total
OPERATING ACTIVITIES
us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions
Share-based Payment Arrangement, Exercise of Option, Tax Benefit
Statement [Line Items]
Allowance for uncollectible accounts
Paid time off accrual
Accounts receivable, net of allowance for uncollectible accounts of $15,000
Stock-based compensation deductions
Deferred tax assets
Share-based Payment Arrangement [Text Block]
Marketable securities, short-term
Additional paid-in capital
AOCI Attributable to Parent [Member]
Shareholders’ equity
Leasehold Improvements [Member]
Property, Plant and Equipment, Policy [Policy Text Block]
Long-Lived Tangible Asset [Axis]
Stock Repurchase Plan Disclosure [Text Block]
The entire disclosure for the stock repurchase plan.
Long-Lived Tangible Asset [Domain]
Business Description and Basis of Presentation [Text Block]
Award Type [Domain]
Fair Value Disclosures [Text Block]
Basis of Presentation and Significant Accounting Policies [Text Block]
Award Type [Axis]
Net income
Net income
1-3 years
Fair value of available-for-sale debt securities maturing in one to three years.
Inventory, Policy [Policy Text Block]
ASSETS
Interest income
us-gaap_Liabilities
Total liabilities
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash used in financing activities
us-gaap_OperatingIncomeLoss
Income from operations
Share-based Payment Arrangement, Option [Member]
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by operating activities
Prepaid expenses and other assets
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash provided by investing activities
us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
Increase in cash and cash equivalents
Cost of sales
us-gaap_GrossProfit
Gross profit
3-5 years
Fair value of available-for-sale debt securities maturing after three through five years.
Less accumulated depreciation and amortization
us-gaap_PropertyPlantAndEquipmentNet
Net fixed assets
Accounting Standards Update 2016-02 [Member]
us-gaap_PropertyPlantAndEquipmentGross
Property, Plant and Equipment, Gross, Ending Balance
Machinery and equipment
Leasehold improvements
Accounting Standards Update [Domain]
us-gaap_DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities
Unrealized (gain) loss on marketable securities
Accounting Standards Update [Axis]
Fixed assets
us-gaap_PaymentsOfDividendsCommonStock
Payment of dividends to shareholders
INVESTING ACTIVITIES
us-gaap_PaymentsForRepurchaseOfCommonStock
Repurchase of common stock
Scenario [Domain]
Forecast [Member]
Securities available for sale
Estimated Fair Value
Retained Earnings [Member]
Proceeds from exercise of stock options
State, Current taxes
State, Deferred taxes
Scenario [Axis]
us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Stock Repurchase Program, Remaining Authorized Repurchase Amount
Accounts payable and accrued expenses
Additional Paid-in Capital [Member]
Share Repurchase Program [Domain]
Federal, Current taxes
Common Stock [Member]
us-gaap_StockRepurchaseProgramAuthorizedAmount1
Stock Repurchase Program, Authorized Amount
Federal, Deferred taxes
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Income before taxes
Provision for income taxes
Income tax provision
Deferred taxes
Equity Components [Axis]
Equity Component [Domain]
Share Repurchase Program [Axis]
Current taxes
nvec_ProductWarrantyTerm
Product Warranty Term (Year)
Represents product warranty term.
us-gaap_OperatingExpenses
Total expenses
us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent
us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
nvec_MonthlyBaseRent
Monthly Base Rent
Represents the amount of monthly base rent.
nvec_SharebasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue
Share-based Compensation Arrangement by Share Based Payment Award Options Grants in Period Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value
Cash and cash equivalents
Cash and cash equivalents at beginning of year
Cash and cash equivalents at end of year
nvec_MonthlyBaseRentAnnualIncreaseInFourYearsPercent
Monthly Base Rent, Annual Increase in Four Years, Percent
The percentage of annual increase for monthly base rent in the fourth fiscal year following the latest fiscal year.
nvec_MonthlyBaseRentAnnualIncreaseInThreeYearsPercent
Monthly Base Rent, Annual Increase in Three Years, Percent
The percentage of annual increase for monthly base rent in the third fiscal year following the latest fiscal year.
Range One [Member]
The first range of exercise prices.
nvec_MonthlyBaseRentAnnualIncreaseInTwoYearsPercent
Monthly Base Rent, Annual Increase in Two Years, Percent
The percentage of annual increase for monthly base rent in the second fiscal year following the latest fiscal year.
Range Two [Member]
The second range of exercise prices
us-gaap_AllocatedShareBasedCompensationExpense
Share-based Payment Arrangement, Expense
Option Shares Reserved [Member]
Award type option shares reserved.
nvec_MonthlyBaseRentAnnualIncreaseInFiveYearsPercent
Monthly Base Rent, Annual Increase in Five Years, Percent
The percentage of annual increase for monthly base rent in the fifth fiscal year following the latest fiscal year.
nvec_DeferredTaxAssetsDepreciation
Depreciation and amortization
Deferred Tax Assets, Depreciation
Machinery and Equipment [Member]
us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit
us-gaap_DefinedBenefitPlanContributionsByEmployer
Defined Benefit Plan, Plan Assets, Contributions by Employer
nvec_StockRepurchaseProgramAuthorizedAdditionalAmount
Stock Repurchase Program Authorized Additional Amount
Amount of additional stock repurchase plan authorized.
Customer B [Member]
Related to customer designated as B
Customer A [Member]
Related to customer designated as A
Cash and Cash Equivalents, Policy [Policy Text Block]
Customer C [Member[
Related to customer designated as C
Receivable [Policy Text Block]
Amendment Flag
us-gaap_UnrecognizedTaxBenefits
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit
Accounting Policies [Abstract]
us-gaap_OpenTaxYear
Open Tax Year
Total comprehensive income
Comprehensive income
Use of Estimates, Policy [Policy Text Block]
New Accounting Pronouncements, Policy [Policy Text Block]
Concentration Risk Disclosure [Text Block]
Entity Interactive Data Current
Cash dividends declared per common share (in dollars per share)
Common Stock, Dividends, Per Share, Declared (in dollars per share)
us-gaap_CommonStockDividendsPerShareCashPaid
Cash dividends declared per common share (in dollars per share)
us-gaap_SharesOutstanding
Balance (in shares)
Balance (in shares)
Common stock, shares outstanding (in shares)
Title of 12(b) Security
us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued
Unrecognized Tax Benefits, Interest on Income Taxes Accrued
Current Fiscal Year End Date
Variable lease cost
us-gaap_LeaseCost
Total
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other assets
nvec_NumberOfOtherThanTemporarilyImpairedAvailableForsaleSecurities
Number of Other-than-temporarily Impaired Available-for-sale Securities
Represents number of other-than-temporarily impaired available-for-sale securities.
Document Fiscal Period Focus
Operating lease cost
Document Fiscal Year Focus
Lease, Cost [Table Text Block]
Document Period End Date
Entity Emerging Growth Company
Concentration Of Risk and Financial Instruments Policy [Policy Text Block]
The policy disclosure of the concentration of risk and financial instrument.
Document Type
Entity Small Business
Entity Shell Company
us-gaap_DividendsCommonStockCash
Cash dividends declared
Document Information [Line Items]
Document Information [Table]
Entity Public Float
Entity Filer Category
Entity Current Reporting Status
Entity Voluntary Filers
Entity Well-known Seasoned Issuer
us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Impairment of Long-Lived Assets Held-for-use
Diluted (in shares)
Shares used in computing net income per share – diluted (in shares)
Percentage of concentration
Concentration Risk, Percentage
us-gaap_IncreaseDecreaseInAccountsReceivable
Accounts receivable
Stock-based compensation
Statement of Comprehensive Income [Abstract]
Entity Central Index Key
us-gaap_DepreciationAndAmortization
Depreciation, Depletion and Amortization, Nonproduction, Total
Entity Registrant Name
Entity [Domain]
Customer Concentration Risk [Member]
Legal Entity [Axis]
Statement [Table]
Statement of Financial Position [Abstract]
Net income per share – diluted (in dollars per share)
Weighted average common shares outstanding – basic (in shares)
Net income per share – basic (in dollars per share)
Concentration Risk Type [Axis]
Concentration Risk Type [Domain]
us-gaap_StockRepurchasedDuringPeriodShares
Stock Repurchased During Period, Shares (in shares)
Repurchase of common stock (in shares)
Statement of Cash Flows [Abstract]
Entity Common Stock, Shares Outstanding (in shares)
Statement of Stockholders' Equity [Abstract]
us-gaap_StockRepurchasedDuringPeriodValue
Repurchase of common stock
Income Statement [Abstract]
Revenue Benchmark [Member]
Remaining lease term (Year)
Accounts Receivable [Member]
Investments [Domain]
us-gaap_IncreaseDecreaseInInventories
Inventories
Trading Symbol
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
Investment Type [Axis]
Investments Classified by Contractual Maturity Date [Table Text Block]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Exercise of stock options (in shares)
Exercised (in shares)
Exercised (in shares)
us-gaap_TableTextBlock
Notes Tables
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]
Exercise of stock options
Selling, general, and administrative
us-gaap_ProvisionForDoubtfulAccounts
Accounts Receivable, Credit Loss Expense (Reversal)
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
Contract Research and Development [Member]
Represents the information pertaining to the contract research and development.
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Granted (in shares)
Granted (in shares)
FINANCING ACTIVITIES
Other
Raw materials
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and shareholders’ equity
Corporate Bond Securities [Member]
Finished goods
Repurchase Program 2009 [Member]
Information pertaining to the 2009 Repurchase Program.
Work in process
Retained earnings
Research and development
Accumulated other comprehensive income (loss)
Money Market Funds [Member]
Changes in operating assets and liabilities:
us-gaap_StockholdersEquity
Total shareholders’ equity
Balance
Balance
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Inventory Disclosure [Text Block]
Subsequent Event [Member]
us-gaap_OperatingLeaseLiabilityNoncurrent
Operating lease
Schedule of Inventory, Current [Table Text Block]
Class of Stock [Axis]
Total lease liabilities
Operating Lease, Liability, Total
Subsequent Event Type [Axis]
Operating lease
Subsequent Event Type [Domain]
Weighted average exercise price (in dollars per share)
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross Unrealized Holding Losses
Retirement Benefits [Text Block]
Weighted average contractual life (Year)
Gross Unrealized Holding Gains
Subsequent Events [Text Block]
Schedule of Weighted Average Number of Shares [Table Text Block]
Right-of-use asset – operating lease
Operating Lease, Right-of-Use Asset
Range of exercise prices, upper limit (in dollars per share)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total lease payments
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Imputed lease interest
Number outstanding (in shares)
Deferred income taxes
Amortized Cost
Exercise Price Range [Axis]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
2023
State income taxes, net of Federal benefit
Exercise Price Range [Domain]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
2024
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive
2025
Range of exercise prices, lower limit (in dollars per share)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
2026
us-gaap_IncomeTaxReconciliationTaxCreditsResearch
Research and development credits