General form of registration statement for all companies including face-amount certificate companies

Weighted Average Assumptions to Value Investor Warrants (Detail)

v2.4.1.9
Weighted Average Assumptions to Value Investor Warrants (Detail) (USD $)
0 Months Ended 12 Months Ended 9 Months Ended
Feb. 06, 2015
Sep. 26, 2014
May 31, 2014
May 31, 2013
Feb. 28, 2015
Debt Instrument [Line Items]          
Expected dividend yield     0.00%us-gaap_FairValueAssumptionsExpectedDividendRate 0.00%us-gaap_FairValueAssumptionsExpectedDividendRate  
Stock price volatility 124.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate 123.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate      
Expected term 5 months 27 days 2 years   2 years  
Risk-free interest rate 0.045%us-gaap_FairValueAssumptionsRiskFreeInterestRate 0.59%us-gaap_FairValueAssumptionsRiskFreeInterestRate   0.28%us-gaap_FairValueAssumptionsRiskFreeInterestRate  
Grant-date fair value $ 1.00us-gaap_FairValueAssumptionsExercisePrice $ 1.00us-gaap_FairValueAssumptionsExercisePrice     $ 1.00us-gaap_FairValueAssumptionsExercisePrice
Minimum          
Debt Instrument [Line Items]          
Stock price volatility     78.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
70.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
90.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Expected term     3 years   5 months 5 days
Risk-free interest rate     0.64%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
  0.041%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Grant-date fair value     0.66us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
0.11us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
 
Maximum          
Debt Instrument [Line Items]          
Stock price volatility     93.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
94.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
114.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Expected term     5 years   1 year 6 months 29 days
Risk-free interest rate     1.42%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
  0.48%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Grant-date fair value     0.72us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
1.10us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_RangeAxis
= us-gaap_MaximumMember