Cover [Abstract] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Interactive Data Current Entity Shell Company Entity Filer Category Entity Small Business Entity Address, State or Province Entity Emerging Growth Company Entity Public Float Entity Common Stock, Shares Outstanding Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Statement [Line Items] Statement [Line Items] Offering costs related to private equity offering Assets [Abstract] Assets Assets Total assets Assets, Current [Abstract] Current assets: Assets, Current Total current assets Cash and Cash Equivalents, at Carrying Value Cash Prepaid Expense, Current Prepaid expenses Prepaid Service Fees Current Prepaid service fees Prepaid service fees current. Restricted Cash, Current Restricted cash Miscellaneous Receivables Current Miscellaneous receivables Represents Miscellaneous Receivables Current. Inventory, Raw Materials, Gross Inventories Intangible Assets, Net (Excluding Goodwill) Intangibles, net Carrying value of intangibles, net Property, Plant and Equipment, Net Property, plant and equipment Operating Lease, Right-of-Use Asset Operating lease right-of-use assets Liabilities and Equity [Abstract] Liabilities and Stockholders' (Deficit) Equity Commitments and Contingencies Commitments and Contingencies (Note 10) Liabilities Total liabilities Liabilities and Equity Total liabilities and stockholders' (deficit) equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Current Accounts payable Accrued License Fees Current Accrued license fees Accrued license fee Accrued license fees current. Convertible Notes Payable, Current Convertible notes payable, net Debt outstanding amount Registered direct offering Employee-related Liabilities, Current Accrued liabilities and compensation Interest Payable, Current Accrued interest on convertible notes Liabilities, Current Total current liabilities Long Term Convertible Notes Payable Current Current portion of long-term convertible notes payable Amount of current portion of long term convertible notes payable. Dividends Payable, Current Accrued dividends on convertible preferred stock Accrued dividends Tender Offer Proceeds held In Trust Warrant exercise proceeds held in trust Represents Warrant tender offer proceeds held in trust. Operating Lease, Liability, Current Current portion of operating leases payable Liabilities, Noncurrent [Abstract] Long-term liabilities: Convertible Notes Payable, Noncurrent Convertible notes payable, net Derivative Liability, Noncurrent Derivative liability Liabilities, Noncurrent Total long-term liabilities Operating Lease, Liability, Noncurrent Operating lease liability Stockholders' Equity Attributable to Parent [Abstract] Stockholders' (Deficit) equity Additional Paid in Capital Additional paid-in capital Common Stock, Value, Issued Common stock, $0.001 par value; 700,000,000 shares authorized, 519,261,580 and 329,554,763 issued and 518,975,572 and 329,395,752 outstanding at May 31, 2020 and May 31, 2019, respectively Preferred Stock, Value, Issued Preferred Stock Value Retained Earnings (Accumulated Deficit) Accumulated (deficit) Stockholders' Equity Attributable to Parent Total stockholders' (deficit) Beginning balance Ending balance Treasury Stock, Common, Value Less: treasury stock, $.001 par value (286,008 and 159,011 shares at May 31, 2020 and May 31, 2019, respectively) Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series B Preferred Stock [Member] Series B Convertible Preferred Stock Series B Convertible Preferred Stock Series C Preferred Stock [Member] Series C Convertible Preferred Stock Series C Convertible Preferred Stock Series D Preferred Stock [Member] Series D Convertible Preferred Stock Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Treasury Stock [Member] Treasury Stock Common Stock, Par or Stated Value Per Share Common stock, par value Common stock per shares Common stock per share price Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock issued Issuance of common stock shares Common Stock, Shares, Outstanding Common stock, shares outstanding Common stock, outstanding Preferred Stock, Par or Stated Value Per Share Preferred stock, par value Convertible preferred stock, par value Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock Shares authorized to be issued Preferred Stock, Shares Issued Preferred stock, shares issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Preferred stock, shares outstanding Series B Convertible preferred stock, shares outstanding Treasury Stock, Common, Shares Treasury stock, shares Income Statement [Abstract] Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Loss before income taxes Income (Loss) from Continuing Operations, Per Basic and Diluted Share Basic and diluted loss per share Income Tax Expense (Benefit) Income tax benefit Interest Expense [Abstract] Interest expense: Amortization of Debt Discount (Premium) Amortization of discount on convertible notes Amortization of discount on convertible notes Amortization of debt discount Debt Related Commitment Fees and Debt Issuance Costs Amortization of debt issuance costs Amortization of debt issuance costs Interest Expense Total interest expense Finance Charges Finance charges Finance charges. Interest Related to Warrant Extensions and Debt Conversion Inducement interest Inducement interest Interest related to warrant extensions and debt conversion. Interest On Convertible Note Payable Interest on convertible note payable Interest on convertible note payable. Net Income (Loss) Attributable to Parent Net loss Net loss Net loss Operating Expenses [Abstract] Operating expenses: Depreciation, Depletion and Amortization, Nonproduction Amortization and depreciation Amortization and depreciation General and Administrative Expense General and administrative Operating Expenses Total operating expenses Operating Income (Loss) Operating loss Research and Development Expense Research and development Weighted Average Number of Shares Outstanding, Basic and Diluted Basic and diluted weighted average common shares outstanding Other Nonoperating Income (Expense) [Abstract] Other income (expense): Investment Income, Interest Interest income Gains Losses On Extinguishment Of Convertible Debt Loss on extinguishment of convertible note Gains losses on extinguishment of convertible debt. Other Income Other income Gain (Loss) Related to Litigation Settlement Legal settlement Change in Fair Value of Derivative Liabilities Change in fair value of derivative liabilities Change in fair value of derivative liabilities. Statement of Stockholders' Equity [Abstract] Shares, Issued Beginning balance, shares Ending balance, shares Stock Issued During Period Value Warrant Exercised Proceeds from warrant exercise Stock Issued During Period Value Warrant Exercised Stock Issued During Period, Value, Acquisitions Acquisition Acquisition of ProstaGene LLC, value Stock Issued During Period Share Warrant Exercised Proceeds from warrant exercise, shares Stock issued during period shares warrant exercise Stock Issued During Period Share Warrant Exercised Acquisition of ProstaGene LLC,shares Acquisition, share Adjustments To Additional Paid In Capital Offering Cost Related To Warrant Tender Offer Offering costs related to warrant tender offer Offering costs related to public warrant tender offers Adjustments to additional paid in capital offering cost related to warrant tender offer Stock Issued During Period, Value, Other Issuance of stock payment shares Issuance Of Common Stock In Private Stock Offering Value Proceeds from private equity offering Issuance Of Common Stock In Private Stock Offering Value Adjustments To Additional Paid In Capital Offering Cost Related To Private Offering Offering costs related to private equity offering Adjustments to additional paid in capital offering cost related to private offering Stock Issued During Period, Shares, Other Issuance of stock payment shares, shares Issuance Of Common Stock In Private Stock Offering Share Proceeds from private equity offering, shares Issuance Of Common Stock In Private Stock Offering Share Adjustments To Additional Paid In Capital Offering Cost Related To Equity Offering Offering costs related to equity offering Adjustments To Additional Paid In Capital Offering Cost Related To Equity Offering Adjustment To Additional Paid In Capital Interest Expense Related To Conversion Of Note Payable Interest expense related to conversion of notes payable Adjustment to additional paid in capital interest expense related to conversion of note payable Issuance Of Common Stock In Registered Direct Offering Shares Proceeds from registered direct offering, shares Issuance Of Common Stock In Registered Direct Offering Shares Issuance Of Common Stock In Registered Direct Offering Value Proceeds from registered direct offering Issuance Of Common Stock In Registered Direct Offering Value Stock Issue During Period Value Offering Costs Related To Registered Direct Offering Offering costs related to registered direct offering, value Stock Issue During Period Value Offering Costs Related To Registered Direct Offering Stock Issue During Period Share Offering Costs Related To Registered Direct Offering Offering costs related to registered direct offering, shares Stock Issue During Period Share Offering Costs Related To Registered Direct Offering Stock Issued During Period, Shares, New Issues Stock issued for bonuses and tendered for income tax, shares Common stock sold at private equity offering Number of shares to be sold Number of shares issued Stock issued during period Adjustment To Additional Paid In Capital Interest Expense Related To Warrant Tender Offer Interest expense related to warrant tender offer Adjustment to additional paid in capital interest expense related to warrant tender offer Stock Issued During Period, Value, New Issues Stock issued for bonuses and tendered for income tax, value Common stock issued Adjustments To Additional Paid In Capital Legal Fees In Connection With Equity Offering Legal fees in connection with equity offerings Adjustments to additional paid in capital legal fees in connection with equity offering Adjustment To Additional Paid In Capital Stock Issued For Board Compensation Stock issued for board compensation Adjustment to additional paid in capital stock issued for board compensation Adjustments to Additional Paid in Capital, Warrant Issued Interest expense related to warrant extension Adjustments To Additional Paid In Capital Debt Discounts On Convertible Notes Payable Debt discount related to convertible notes payable Adjustments To Additional Paid In Capital Debt Discounts On Convertible Notes Payable Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Stock-based compensation Issuance of stock for note payable redemption Issuance of stock for note payable redemptions and conversions Value of stock issued during period for notes payable. Issuance of stock for note payable redemption ,shares Issuance of stock for note payable redemptions and conversions , shares The number of stock issued during period for redemption of note payable. Adjustments to Additional Paid in Capital Offering Costs Related to Debt Offering Offering costs related to debt offering Amount of increase in additional paid in capital (APIC) resulting from offering costs related to debt offering. Adjustments to Additional Paid in Capital Debt Discount and Issuance Costs Related to Debt Offering Debt discount and issuance costs related to offering Amount of increase in additional paid in capital (APIC) resulting from debt discount and issuance costs related to debt offering. Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature Beneficial conversion feature on note payable and relative fair value associated with warrants Adjustments To Additional Paid In Capital Offering Cost Related To Exercise Of Warrants Offering costs related to private warrant exchange Represents Adjustments To Additional Paid In Capital Offering Cost Related To Exercise Of Warrants. Adjustments To Additional Paid In Capital Inducement Of Interest Expense On Warrant Exchange Inducement interest expense on private warrant exchange Represents Adjustments To Additional Paid In Capital Inducement Of Interest Expense On Warrant Exchange. Stock Issued During Period Series C Convertible Stock Value Proceeds from Series C Convertible Preferred offering Represents Stock Issued During Period Series C Convertible Stock Value. Stock Issued During Period Series C Convertible Stock Shares Proceeds from Series C Convertible Preferred offering, shares Represents Stock Issued During Period Series C Convertible Stock Shares. Dividends On Series C Preferred Stock Dividends on Series C Convertible Preferred shares Represents Dividends On Series C Preferred Stock. Adjustments To Additional Paid In Capital Legal Fee With Registered Offerings Legal fees in connection with registered offerings Adjustments to additional paid in capital legal fee with registered offerings. Stock Issued During Period Value PrivateWarrant Exercised Proceeds from private warrant exchange Value of stock issued during private warrant exercised. Stock Issued During Period Shares Private Warrant Exercised Proceeds from private warrant exchange, shares No of stock issued during private warrant exercised. Stock Issued During The Period Value Of Note Conversion And Extension Fees Note conversion and extension fees StockIssuedDuringThePeriodValueOfNoteConversionAndExtensionFees. Adjustments To Additional Paid In Capital Relative Fai rMarket Value Associated With Warrants Exercised Relative fair market value associated with warrants exercised Adjustments To Additional Paid In Capital Relative Fair Market Value Associated With Warrants Exercised. Issuance Of Public Warrants Through Tender Offering Value Proceeds from public warrant tender offers Issuance Of Public Warrants Through Tender Offering Value. Stock Issued During Period, Value, Stock Options Exercised Exercise of option to repurchase common stock Stock Issued During Period Value For Exercise Of Stock Options Exercise of stock options Stock Issued During Period Value For Exercise Of Stock Options. Stock Issued During Period Shares For Exercise Of Stock Options Exercise of stock options, shares Stock Issued During Period Shares For Exercise Of Stock Options. Stock Issued During Period SeriesC preffered Stock Value Proceeds from Series C Preferred offering Stock Issued During Period SeriesC preffered Stock Value. Adjustments To Additiona lPaid InCapital Offering Cost Related To SeriesC Preferred Offering Offering costs related to Series C Preferred offering Adjustments To Additiona lPaid InCapital Offering Cost Related To SeriesC Preferred Offering. Dividends On SeriesC Preferred Stock Dividends on Series C Preferred shares Dividends On SeriesC Preferred Stock. Stock Issued During Period SeriesD pereffered Stock Shares Proceeds from Series D Preferred offering , shares Stock Issued During Period SeriesD pereffered Stock Shares. Adjustments To Additional Paid In Capital Offering Cost Related To SeriesD Preferred Offering Offering costs related to Series D Preferred offering Adjustments To Additional Paid In Capital Offering Cost Related To SeriesD Preferred Offering. Dividends On SeriesD Preferred Stock Dividends on Series D Preferred shares Dividends On SeriesD Preferred Stock. Stock Issued During Period, Value, Issued for Services Stock issued for services Stock Issued During Period, Shares, Issued for Services Stock issued for services, shares AdjustmentsTo Additional Paid In Capital Inducement Of Debt Conversions Inducement interest expense - tender offers and debt conversions Adjustments To Additional Paid In Capital Inducement O fDebt Conversions. Stock Issued During The Period Shares Note Conversion And Extension Fees Note conversion and extension fees, Shares Stock Issued During The Period Shares Note Conversion And Extension Fees. Issuance Of Public WarrantsThrough Tender Offering Shares Proceeds from public warrant tender offers (shares) Issuance of public warrants through tender offering shares. Stock Issued During Period Series D Preferred Stock Value Proceeds from Series D Preferred offering Stock issued during period series D preferred stock value. Preferred Stock [Member] Common Stock [Member] Common Stock Additional Paid-in Capital [Member] Accumulated Deficit Accumulated Deficit [Member] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Exercise Price Range [Axis] Exercise Price Range [Axis] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Exercise Price One [Member] Exercise Price 1 cydy:ExercisePriceOneMember Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario, Unspecified [Domain] Warrants Granted Per Share Warrants Granted Per Share Shares Issued, Price Per Share Proceeds from private equity offering, per share Issuance Of Common Stock In Registered Direct Offering Per Share Proceeds from registered direct offering, per share Issuance Of Common Stock In Registered Direct Offering Per Share Statement of Cash Flows [Abstract] Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, beginning of period Cash, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Net change in cash Net Cash Provided by (Used in) Financing Activities [Abstract] Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Proceeds From Issuance Of Common Stock And Warrants Proceeds from sale of common stock and warrants Proceeds from sale of common stock and warrant Proceeds from issuance of common stock and warrants. Proceeds from Warrant Exercises Proceeds from warrant exercises Proceeds From Exercise Of Warrants Payments of Debt Issuance Costs Payment of debt issuance costs Proceeds from Issuance of Preferred Stock and Preference Stock Proceeds from sale of preferred stock Proceeds From Stock Option Excercises Proceeds from stock option excercises Proceeds from stock option excercises. Payments of Principal on Maturity of Short Term Convertible Notes Principal paid on maturity of short-term convertible notes Payments Of Principal On Maturity Of Short Term Convertible Notes. Repayments of Notes Payable Convertible note redemptions paid in cash Repayment of note Notes Payable Repayment Repayment of principal and interest on convertible note Exercise of Option to Stock Buy back or Repurchase Shares HeldiIn ESCROW Exercise of option to repurchase shares held in escrow Exercise of option to stock buyback or repurchase shares held in escrow. Payment of Bonuses and Payroll Taxes Payment of bonuses and payroll taxes related to tender of common stock for income tax withholding Payment of bonuses and payroll taxes. Payments for warrant tender offer held in trust (Release) proceeds of funds held in trust for warrant tender offer The cash outflow payments for warrant tender offer held in trust. Proceeds from Convertible Debt Proceeds from convertible note payable, net Net Proceeds Repayment Of Principal And Interest On Convertible Note Repayment of principal and interest on convertible note Repayment of principal and interest on convertible note.