Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)

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Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)
 1 Months Ended 3 Months Ended 6 Months Ended
Feb. 02, 2012
USD ($)
Dec. 31, 2005
USD ($)
May. 31, 2015
USD ($)
CompensationPlan
May. 31, 2014
USD ($)
May. 31, 2015
USD ($)
CompensationPlan
Deliverables
May. 31, 2014
USD ($)
Nov. 30, 2014
USD ($)
Basis of Presentation and Significant Accounting Policies [Line Items]              
Number of deliverables for revenue recognized | Deliverables         2    
Contracted storage periods option two         21 years    
Contracted storage periods option one         1 year    
Contracted storage periods option three         Lifetime    
Deferred revenue recognition period         12 months    
Valuation allowance     $ 10,187,000   $ 10,187,000   $ 10,517,000
U.S. Income tax expense     0 $ 0 0 $ 0  
Foreign income tax expense     25,000 25,000 51,000 73,000  
Provisions for interest or penalties related to uncertain tax positions     0 0 0 0  
Uncertain tax provisions     0 0 0 0  
Impairment on long-lived assets     $ 0 0 $ 0 0  
Abandonment of patents       25,649   25,649  
Number of employees stock-based compensation plan | CompensationPlan     3   3    
Stock-based compensation expense     $ 54,000 56,000 $ 245,000 208,000  
Unrealized holding gains, available-for-sale securities     226,276 0 226,276 0  
Payment warranty   $ 50,000          
Increased payment warranty $ 75,000            
Additional payment warranty $ 10,000            
Reserves recorded under programs     17,000   17,000   $ 17,000
Other Income and Expense [Member]              
Basis of Presentation and Significant Accounting Policies [Line Items]              
Unrealized holding gain and loss, trading securities     3,768 $ 7,354 (645) $ 22,879  
Realized gains on disposition of available for sale securities     $ 7,361   $ 7,361