Quarterly report pursuant to Section 13 or 15(d)

Stock Options and Warrants - Additional Information (Detail)

v2.4.1.9
Stock Options and Warrants - Additional Information (Detail) (USD $)
 3 Months Ended 6 Months Ended
Nov. 30, 2014
Phase
Tranche
Nov. 30, 2013
Nov. 30, 2014
Phase
Tranche
Nov. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares of Common Stock issued upon exercise 250,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights   250,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights  
Warrants granted, exercise price $ 0.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1   $ 0.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1  
Term of warrants     5 years  
Cash proceeds from warrant exercises     $ 777,333us-gaap_ProceedsFromWarrantExercises $ 50,000us-gaap_ProceedsFromWarrantExercises
Convertible Debt        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares of Common Stock issued upon exercise 1,413,333us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember 		  1,413,333us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember 		 
Cash proceeds from warrant exercises     777,333us-gaap_ProceedsFromWarrantExercises
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember 		 
Convertible Debt | Director        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Cash proceeds from warrant exercises     733,333us-gaap_ProceedsFromWarrantExercises
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleDebtMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember 		 
2012 Equity Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares of Common Stock issued upon exercise 150,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  150,000us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Warrants granted, exercise price $ 1.05us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  $ 1.05us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Number of tranches 3cydy_NumberOfTranchesForVestingOfWarrants
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  3cydy_NumberOfTranchesForVestingOfWarrants
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Term of warrants     5 years  
Shares vested in each tranche     50,000cydy_NumberOfSharesVestedInEachTrancheOfWarrants
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Number of milestone for warrant vesting 3cydy_NumberOfMilestonesForVestingOfWarrants
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  3cydy_NumberOfMilestonesForVestingOfWarrants
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Compensation expense related to stock options and warrants 150,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		261,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		287,800us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		487,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
Grant date fair value of options 227,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValueOfOptions
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		459,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValueOfOptions
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		309,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValueOfOptions
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		1,574,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValueOfOptions
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
Grant date fair value of warrants vested 227,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueOfWarrantsIssued
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		459,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueOfWarrantsIssued
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		309,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueOfWarrantsIssued
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		1,574,000cydy_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueOfWarrantsIssued
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
Unrecognized compensation costs $ 691,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  $ 691,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Weighted average period over which unrecognized compensation costs is expected to be recognized     1 year 5 months 1 day  
2012 Equity Incentive Plan | Stock Options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares available for future issuance 3,000,000us-gaap_DeferredCompensationArrangementWithIndividualSharesAuthorizedForIssuance
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  3,000,000us-gaap_DeferredCompensationArrangementWithIndividualSharesAuthorizedForIssuance
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
Shares available for future stock-based grants 754,930us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		  754,930us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember 		 
2012 Equity Incentive Plan | Stock Options | Directors and Employee        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options granted, shares     483,973us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_DirectorsAndEmployeesMember 		 
Stock options grant date fair value     $ 0.43us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_DirectorsAndEmployeesMember 		 
2012 Equity Incentive Plan | Stock Options | Directors and Employee | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options granted, exercise price     $ 0.66us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_DirectorsAndEmployeesMember 		 
2012 Equity Incentive Plan | Stock Options | Directors and Employee | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options granted, exercise price     $ 0.81us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_DirectorsAndEmployeesMember 		 
2012 Equity Incentive Plan | Stock Options | Director        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options, term     5 years  
Stock options grant date fair value     $ 0.35us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember 		 
2012 Equity Incentive Plan | Stock Options | Director | Vesting Schedule One        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options, number of shares vested     333,973us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
/ us-gaap_VestingAxis
= cydy_VestingScheduleOneMember 		 
Stock options, vesting period     1 year  
Percentage of option awards vesting     25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
/ us-gaap_VestingAxis
= cydy_VestingScheduleOneMember 		 
2012 Equity Incentive Plan | Stock Options | Director | Vesting Schedule Two        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options, number of shares vested     100,000us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
/ us-gaap_VestingAxis
= cydy_VestingScheduleTwoMember 		 
Stock options, vesting period     2 years  
Percentage of option awards vesting     50.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_DirectorMember
/ us-gaap_VestingAxis
= cydy_VestingScheduleTwoMember 		 
2012 Equity Incentive Plan | Stock Options | Employees        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options, number of shares vested     50,000us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= cydy_TwoThousandTwelveStockIncentivePlanMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= cydy_EmployeesMember 		 
Stock options, vesting period     3 years  
Stock options, term     5 years