| Net Deferred Tax Assets and Liabilities (Detail) - USD ($) | May. 31, 2015 | May. 31, 2014 | 
|---|---|---|
| Schedule Of Income Taxes [Line Items] | ||
| Accrued expenses | $ 219,100 | $ 159,300 | 
| Debt discount and amortization | 0 | 0 | 
| Valuation allowance | (219,100) | (159,300) | 
| Deferred Tax Assets, Net, Current, Total | 0 | 0 | 
| Net operating loss | 16,857,600 | 9,957,400 | 
| Debt discount | (902,700) | (663,700) | 
| Expense on non-qualified stock options | 3,073,500 | 2,893,300 | 
| Other | 211,700 | 176,200 | 
| Valuation allowance | (19,240,100) | 12,363,200 | 
| Deferred Tax Assets, Net, Noncurrent, Total | $ 0 | $ 0 | 
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- Definition Schedule Of Income Taxes [Line Items] No definition available. 
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- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, netted by jurisdiction and classified as current. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, netted by jurisdiction and classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from deferred financing costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from financing arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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