Quarterly report pursuant to Section 13 or 15(d)

Significant Inputs and Assumptions Used in Binomial Lattice Model for Derivative Liability (Detail)

Significant Inputs and Assumptions Used in Binomial Lattice Model for Derivative Liability (Detail) (USD $)
0 Months Ended 6 Months Ended
Sep. 26, 2014
Nov. 30, 2014
Sep. 26, 2014
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]      
Quoted market price on valuation date $ 0.79us-gaap_FairValueInputsOfferedQuotes $ 1.24us-gaap_FairValueInputsOfferedQuotes  
Contractual conversion rate   $ 1.00us-gaap_FairValueAssumptionsExercisePrice $ 1.00us-gaap_FairValueAssumptionsExercisePrice
Adjusted conversion price $ 0.9759cydy_FairValueAssumptionsAdjustedConversionPrice [1] $ 1.0000cydy_FairValueAssumptionsAdjustedConversionPrice [1]  
Contractual term to maturity (years) 2 years 1 year 9 months 26 days  
Expected volatility 123.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate 120.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate  
Contractual interest rate 5.00%cydy_FairValueAssumptionsContractualInterestRate 5.00%cydy_FairValueAssumptionsContractualInterestRate  
Risk-free rate 0.59%us-gaap_FairValueAssumptionsRiskFreeInterestRate 0.29%us-gaap_FairValueAssumptionsRiskFreeInterestRate  
Risk adjusted rate 2.69%cydy_FairValueAssumptionsRiskAdjustedRate 3.05%cydy_FairValueAssumptionsRiskAdjustedRate  
Probability of event of default 5.00%us-gaap_FairValueInputsProbabilityOfDefault 5.00%us-gaap_FairValueInputsProbabilityOfDefault  
[1] The adjusted conversion price input used in the Binomial Lattice Model considers the potential for an adjustment to the stated conversion price due to a future dilutive issuance. This input was calculated using a probability-weighted approach which considered the likelihood of various scenarios occurring including (i) potential success or failure of various phases for PRO 140, (ii) the probability the Company will enter into a future financing and (iii) and the potential price of a future financing.