Document And Entity Information [Abstract] Document And Entity Information [Abstract] Statement [Table] Statement [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Filer Category Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Common Stock, Shares Outstanding Consolidated Balance Sheets [Abstract] Assets Abstract ASSETS Cash and Cash Equivalents, at Carrying Value CASH AND CASH EQUIVALENTS AT END OF PERIOD CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value, Total Marketable Securities Marketable securities Marketable Securities, Total Accounts Receivable, Net, Current Accounts receivable, less allowance of $800 and $800 Accounts Receivable, Net, Current, Total Inventory, Net Inventories Inventories Deferred Tax Assets, Net, Current Deferred Tax Assets, Net, Current, Ending Balance Deferred Tax Assets, Net, Current, Beginning Balance Deferred income taxes Deferred Tax Assets, Net, Current, Total Prepaid Expense And Other Assets Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current, Total Assets, Current TOTAL CURRENT ASSETS TOTAL CURRENT ASSETS Property, Plant and Equipment, Net Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance NET PROPERTY AND EQUIPMENT Property, Plant and Equipment, Net, Total OTHER ASSETS Goodwill Goodwill, Ending Balance Goodwill, Beginning Balance Goodwill, Total Other Indefinite-lived Intangible Assets Other non-amortizable intangible assets Acquired Finite-lived Intangible Asset, Amount Customer based intangibles, net of accumulated amortization of $6,689 and $5,431 Intangible Assets, Net (Excluding Goodwill) Other non-current assets, net of accumulated amortization of $3,385 and $2,789 Intangible Assets, Net (Excluding Goodwill), Total Customer based intangibles, net of accumulated amortization of $5,162 and $4,002 Other Assets, Total TOTAL OTHER ASSETS Assets TOTAL ASSETS TOTAL ASSETS Total assets LIABILITIES AND EQUITY Accounts Payable, Current Accounts payable Accounts Payable, Current, Total Employee-related Liabilities, Current Employee-related Liabilities, Current, Total Accrued compensation Accrued Income Taxes, Current Income taxes Other Accrued Liabilities, Current Other accruals Liabilities, Current TOTAL CURRENT LIABILITIES TOTAL CURRENT LIABILITIES Deferred Tax Liabilities, Noncurrent DEFERRED INCOME TAXES Other Long-term Debt, Noncurrent OTHER LONG-TERM LIABILITIES Liabilities, Noncurrent TOTAL NONCURRENT LIABILITIES Liabilities TOTAL LIABILITIES TOTAL LIABILITIES Stockholders' Equity Attributable to Parent [Abstract] EQUITY Preferred Stock, Value, Issued Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued, Beginning Balance Preferred stock, $1.00 par value, 100,000 shares authorized, none issued and outstanding Preferred Stock, Value, Issued, Total Common Stock, Value, Issued Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common stock, $.16 par value, 60,000,000 shares authorized, 23,553,508 and 23,290,604 shares issued and outstanding at February 29, 2012 and May 31, 2011, respectively Common Stock, Value, Issued, Total Additional Paid in Capital Additional Paid in Capital, Ending Balance Additional Paid in Capital, Beginning Balance Additional paid-in capital Additional Paid in Capital, Total Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained earnings Retained Earnings (Accumulated Deficit), Total Stockholders' Equity Attributable to Parent Balance Balance Total Neogen Corporation Stockholders' Equity Total Neogen Corporation Stockholders' Equity Balance, June 1, 2010 Stockholders' Equity Attributable to Noncontrolling Interest Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance Stockholders' Equity Attributable to Noncontrolling Interest, Beginning Balance Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest, Total Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Balance Balance TOTAL EQUITY TOTAL EQUITY Liabilities and Stockholders' Equity TOTAL LIABILITIES AND EQUITY TOTAL LIABILITIES AND EQUITY Allowance for Doubtful Accounts Receivable, Current Allowance for Doubtful Accounts Receivable, Current, Ending Balance Allowance for Doubtful Accounts Receivable, Current, Beginning Balance Allowance for doubtful accounts receivable Accumulated amortization of acquired intangible assets. Accumulated Amortization Of Acquired Intangible Assets Accumulated amortization for customer based intangibles Finite-Lived Intangible Assets, Accumulated Amortization Accumulated amortization for other non-current assets Accumulated amortization for customer based intangibles Preferred Stock, Par or Stated Value Per Share Preferred stock, par value Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred stock, shares issued Preferred Stock, Shares Issued, Total Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, shares outstanding Common Stock, Par or Stated Value Per Share Common stock, par value Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock, Shares, Issued, Total Common Stock, Shares, Outstanding Balance, shares Balance, shares Common stock, shares outstanding Consolidated Statements Of Income [Abstract] Sales Revenue, Net Net sales Sales Revenue, Net, Total Net sales to external customers Cost of Goods Sold Cost of goods sold Cost of Goods Sold, Total Gross Profit Gross Profit, Total GROSS MARGIN OPERATING EXPENSES Selling and Marketing Expense Sales and marketing Selling and Marketing Expense, Total General and Administrative Expense General and administrative General and Administrative Expense, Total Research and Development Expense Research and development Research and Development Expense, Total Operating Expenses, Total TOTAL OPERATING EXPENSES Operating Income (Loss) Operating Income (Loss), Total OPERATING INCOME Operating income (reduction) OTHER INCOME (EXPENSE) Investment Income, Interest Interest income Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset Change in purchase consideration Change in purchase consideration Other Nonoperating Income (Expense), Total Other income (expense) Other nonoperating income (expense) Other income (expense) Nonoperating Income (Expense) TOTAL OTHER INCOME(EXPENSE) Nonoperating Income (Expense), Total Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest, Total INCOME BEFORE INCOME TAXES Income Tax Expense (Benefit) INCOME TAXES Income Tax Expense (Benefit), Total Net Income (Loss) Attributable to Parent Net income (loss) for the nine months ended February 29, 2012 less noncontrolling interest NET INCOME Net income Net Income Per Share [Abstract] NET INCOME PER SHARE Earnings Per Share, Basic Basic Earnings Per Share, Basic, Total Earnings Per Share, Diluted Diluted Earnings Per Share, Diluted, Total Consolidated Statement Of Equity [Abstract] Statement, Scenario [Axis] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Additional Paid-In Capital [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Member] Retained Earnings [Member] Retained Earnings [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Stock Issued During Period, Value, Share-based Compensation Issuance of shares of common stock under equity compensation plans, and share based compensation, including $1,432 of excess income tax benefit Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures, Total Stock Issued During Period, Shares, Share-based Compensation Issuance of shares of common stock under equity compensation plans, and share based compensation, including $1,432 of excess income tax benefit, shares Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures, Total Stock Issued During Period, Value, Employee Stock Purchase Plan Issuance of shares under employee stock purchase plan Stock Issued During Period, Shares, Employee Stock Purchase Plans Issuance of shares under employee stock purchase plan, shares Comprehensive income: Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total Foreign currency translation adjustments Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest Total comprehensive income ($12,426 in the nine months ended February 28, 2010) Total comprehensive income ($18,030 in the nine months ended February 28, 2011) Proceeds and Excess Tax Benefit from Share-based Compensation Issuance of shares of common stock under equity compensation plans, and share based compensation, excess income tax benefit Comprehensive Income, Net of Tax, Attributable to Parent Comprehensive Income Net Of Tax Total comprehensive income Consolidated Statements Of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Adjustments to reconcile net income to net cash provided by operating activities: Depreciation, Depletion and Amortization Depreciation and amortization Depreciation, Depletion and Amortization, Total Share-based Compensation Share based compensation Share-based Compensation, Total Excess Tax Benefit from Share-based Compensation, Operating Activities Excess income tax benefit from the exercise of stock options Excess income tax benefit from the exercise of stock options Excess income tax benefit Changes in operating assets and liabilities, net of business acquisitions: Increase (Decrease) in Accounts Receivable Accounts receivable Accounts receivable Increase (Decrease) in Inventories Inventories Inventories Increase (Decrease) in Inventories, Total Increase (Decrease) in Prepaid, Deferred Expense and Other Assets Prepaid expenses and other current assets Prepaid expenses and other current assets Increase (Decrease) in Prepaid, Deferred Expense and Other Assets, Total Increase (Decrease) in Accounts Payable and Accrued Liabilities Accounts payable, accruals and other Increase (Decrease) in Accounts Payable and Accrued Liabilities, Total Net Cash Provided by (Used in) Operating Activities Net Cash Provided by (Used in) Operating Activities, Total NET CASH PROVIDED BY OPERATING ACTIVITIES CASH FLOWS FROM INVESTING ACTIVITIES: Payments to Acquire Productive Assets Purchases of property and equipment and other assets Purchases of property and equipment and other assets Payments to Acquire Productive Assets, Total Proceeds from Sale and Maturity of Marketable Securities Proceeds from the sale of marketable securities Proceeds from Sale and Maturity of Marketable Securities, Total Payments to Acquire Marketable Securities Purchases of marketable securities Purchases of marketable securities Payments to Acquire Marketable Securities, Total Payments to Acquire Businesses, Net of Cash Acquired Payments for business acquisitions Payments to Acquire Businesses, Net of Cash Acquired, Total Payments for business acquisitions Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Investing Activities, Total NET CASH USED IN INVESTING ACTIVITIES CASH FLOWS FROM FINANCING ACTIVITIES: Other Long Term Liability Increases in other long-term liabilities Increase (decrease) in other long-term liabilities Proceeds from Issuance of Common Stock Net proceeds from issuance of common stock Excess Tax Benefit from Share-based Compensation, Financing Activities Excess income tax benefit from the exercise of stock options Net Cash Provided by (Used in) Financing Activities Net Cash Provided by (Used in) Financing Activities, Total NET CASH PROVIDED BY FINANCING ACTIVITIES Effect of Exchange Rate on Cash and Cash Equivalents Effect of Exchange Rate on Cash and Cash Equivalents, Total EFFECT OF EXCHANGE RATE ON CASH Cash and Cash Equivalents, Period Increase (Decrease) INCREASE IN CASH Cash and Cash Equivalents, Period Increase (Decrease), Total Basis Of Presentation [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Basis Of Presentation Inventories [Abstract] Inventory Disclosure [Text Block] Inventories Earnings Per Share [Text Block] Net Income Per Share Segment Information [Abstract] Segment Reporting Disclosure [Text Block] Segment Information Equity Compensation Plans [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Equity Compensation Plans New Accounting Pronouncements [Abstract] Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Text Block] New Accounting Pronouncements Business And Product Line Acquisitions [Abstract] Business Combination Disclosure [Text Block] Business And Product Line Acquisitions Long Term Debt [Abstract] Debt Disclosure [Text Block] Long Term Debt Commitments And Contingencies [Abstract] Commitments and Contingencies Disclosure [Text Block] Commitments And Contingencies Stock Purchase [Abstract] Stock Purchase [Abstract] Stock Purchase Disclosure [Text Block] Stock Purchase Disclosure [Text Block] Stock Purchase Schedule of Inventory, Current [Table Text Block] Components Of Inventories Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Calculation Of Net Income Per Share Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule Of Segment Information Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Summary Of Stock Option Activity Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Fair Value Of Stock Options Granted, Estimated Using Weighted-Average Assumptions Inventory, Raw Materials Raw materials Inventory, Raw Materials, Total Inventory, Work in Process Work-in-process Inventory, Finished Goods Inventory, Finished Goods, Total Finished and purchased goods Weighted Average Number of Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Basic, Total Weighted average shares Incremental Common Shares Attributable to Call Options and Warrants Effect of dilutive stock options and warrants Weighted Average Number of Shares Outstanding, Diluted Denominator for diluted net income per share Denominator for diluted net income per share Schedule of Segment Reporting Information, by Segment [Table] Statement, Business Segments [Axis] Segment [Domain] Segment [Domain] Food Safety [Member] Food Safety [Member] Food Safety [Member] Animal Safety [Member] Animal Safety [Member] Animal Safety [Member] Corporate Elimination [Member] Corporate And Eliminations [Member] Segment Reporting Information [Line Items] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Deferred Compensation Arrangement with Individual, Share-based Payments, by Type of Deferred Compensation [Axis] Type Of Deferred Compensation [Domain] Type of Deferred Compensation [Domain] Deferred Compensation Share Based Payments [Member] Deferred Compensation, Share-based Payments [Member] Employee Stock Option [Member] Employee Stock Option [Member] Director Stock Option Director Stock Option [Member] Director Stock Option [Member] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Employee And Director Stock Option [Member] Employee And Director Stock Option [Member] Employee And Director Stock Option [Member] Non Qualified Options [Member] Non Qualified Options [Member] Non-Qualified Options [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Stock options grant period, years Allocated Share-based Compensation Expense Compensation expense Allocated Share-based Compensation Expense, Total Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted-average fair value of stock options granted Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date Employee stock purchases discount Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Shares, Options outstanding at February 29, 2012 Shares, Options outstanding at June 1, 2011 Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Shares, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures, Total Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares, Exercised Shares, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Shares, Forfeited Shares, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted-Average Exercise Price, Options outstanding at February 29, 2012 Weighted-Average Exercise Price, Options outstanding at June 1, 2011 Options outstanding at August 31, 2011 Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted-Average Exercise Price, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-Average Exercise Price, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted-Average Exercise Price, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Expected dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected stock price volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected option life (in years) Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition Acquiree [Domain] Business Acquisition, Acquiree [Domain] GeneSeek [Member] Geneseek [Member] GeneSeek, Inc. [Member] VeroMara [Member] Veromara [Member] VeroMara [Member] Glycomar Limited [Member] Glycomar Limited [Member] GlycoMar Ltd. [Member] Business Acquisition [Line Items] Business Acquisition, Cost of Acquired Entity, Cash Paid Cash consideration for purchase of business Business Acquisition, Purchase Price Allocation, Noncurrent Assets Allocation of purchase price for fixed assets Business Acquisition, Purchase Price Allocation, Noncurrent Assets, Total Business Acquisition, Contingent Consideration, Potential Cash Payment Cash consideration for purchase of business Secondary payment obligations Business Acquisition, Purchase Price Allocation, Current Assets, Receivables Allocation of purchase price for accounts receivable Business Acquisition, Purchase Price Allocation, Current Assets, Inventory Allocation of purchase price for inventory Business Acquisition, Purchase Price Allocation, Current Assets, Inventory, Total Business Acquisition, Purchase Price Allocation, Current Liabilities Allocation of purchase price for current liabilities Business Acquisition, Purchase Price Allocation, Current Liabilities, Total Business Acquisition Purchase Price Allocation Deferred Tax Liabilities Business Acquisition Purchase Price Allocation Deferred Tax Liabilities Allocation of purchase price for deferred tax liabilities Business Acquisition, Purchase Price Allocation, Liabilities Assumed Allocation of purchase price for secondary payment liabilities Finite-Lived Intangible Assets, Useful Life, Minimum Goodwill and other intangible assets estimated lives-minimum (years) Finite-Lived Intangible Assets, Useful Life, Maximum Goodwill and other intangible assets estimated lives-maximum (years) Business Acquisition Purchase Price Allocation Increase In Fair Value Charged To Other Income Expense Business Acquisition Purchase Price Allocation Increase In Fair Value Charged To Other Income Expenses Charge to other income (expense) due to increase in fair value of secondary payment liability Payments to Acquire in Process Research and Development Acquired testing laboratory by cash Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Acquiree revenues Line of Credit Facility, Maximum Borrowing Capacity Unsecured revolving line of credit, total amount available Line of Credit Facility, Increase, Additional Borrowings Unsecured revolving line of credit, increase in available credit Line of Credit Facility, Interest Rate Description Unsecured revolving line of credit, interest terms Line of Credit Facility, Interest Rate at Period End Unsecured revolving line of credit, interest rate Range [Axis] Range [Member] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Environmental Remediation Expense Environmental remediation expense Environmental Remediation Expense, Period Of Remediation Environmental Remediation Expense, Period Of Remediation Environmental remediation expense, period of remediation, years Accrued Environmental Loss Contingencies, Noncurrent Estimated liability costs of remediation Accrual For Environmental Loss Contingencies Undiscounted Estimated Period Accrual For Environmental Loss Contingencies Undiscounted Estimated Period Estimated liability, measurement period, years Stock Repurchase Program, Number of Shares Authorized to be Repurchased Shares authorized to purchase Stock repurchase program number of shares repurchased Stock Repurchase Program Number Of Shares Repurchased Cumulative number of shares repurchased Stock repurchase program total cost of repurchased shares Stock Repurchase Program Total Cost Of Repurchased Shares Cost of repurchased shares, including commissions Scenario Unspecified [Domain] Scenario, Unspecified [Domain]