Quarterly report pursuant to Section 13 or 15(d)

Related Party Transactions - Additional Information (Detail)

v2.4.1.9
Related Party Transactions - Additional Information (Detail) (USD $)
6 Months Ended
Nov. 30, 2014
Nov. 30, 2013
May 31, 2014
Related Party Transaction [Line Items]      
Face amount of notes $ 0cydy_ConvertibleNotesFaceAmount   $ 1,200,000cydy_ConvertibleNotesFaceAmount
Debt conversion price $ 0.75us-gaap_DebtInstrumentConvertibleConversionPrice1    
Warrants to purchase common shares, shares 250,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights    
Warrants exercise price per share $ 0.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1    
Proceeds from exercise of warrants 777,333us-gaap_ProceedsFromWarrantExercises 50,000us-gaap_ProceedsFromWarrantExercises  
Convertible Debt      
Related Party Transaction [Line Items]      
Warrants to purchase common shares, shares 1,413,333us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember
   
Proceeds from exercise of warrants 777,333us-gaap_ProceedsFromWarrantExercises
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember
   
Alpha Venture Capital Partners, L.P.      
Related Party Transaction [Line Items]      
Face amount of notes 2,000,000cydy_ConvertibleNotesFaceAmount
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Interest rate on convertible notes 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Convertible note maturity date Sep. 26, 2016    
Debt conversion price $ 1.00us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Percentage reduction to conversion price 10.00%cydy_PercentageOfCurrentConversionPriceLowerThanClosingSalePrice
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Sale price of common stock $ 0.9444us-gaap_SharePrice
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Additional convertible promissory notes that may be issued 6,000,000cydy_AdditionalDebtInstrumentFaceAmountThatMayBeIssued
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Warrants to purchase common shares, shares 250,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Warrants exercise price per share $ 0.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_AlphaVentureCapitalPartnersLPMember
   
Warrants, expiration date Dec. 31, 2019    
Director | Convertible Debt      
Related Party Transaction [Line Items]      
Convertible notes issued, principal amount 1,000,000us-gaap_NotesIssued1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
   
Common stock warrants issued 1,333,333us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
   
Proceeds from exercise of warrants $ 733,333us-gaap_ProceedsFromWarrantExercises
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
   
Convertible notes term 3 years