Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Details)

v3.8.0.1
Stockholders' Equity (Details) - USD ($)
 9 Months Ended 12 Months Ended
Apr. 30, 2018
Apr. 30, 2017
Jul. 31, 2017
Dec. 31, 2014
Stockholders' Equity (Details) [Line Items]        
Common Stock, Par or Stated Value Per Share (in Dollars per share) $ 0.01   $ 0.01  
Percentage of Commission Payable on Equity Offering 3.00%      
Maximum Offering Price Under Sales Agreement $ 20,000,000     $ 20,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in Shares) 615,624      
Excess Tax Benefit from Share-based Compensation, Financing Activities $ 0 $ 0    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 900,000      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 14 months      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value $ 22,000 19,000    
Stock Issued During Period, Value, Employee Benefit Plan 782,000 $ 724,000 $ 724,000  
Restricted Stock [Member]        
Stockholders' Equity (Details) [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options $ 100,000      
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Outstanding Weighted Average Remaining Contractual Terms 22 months      
2011 Plan [Member]        
Stockholders' Equity (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares) 5,000,000   3,000,000  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in Shares) 2,266,800      
Common Stock [Member]        
Stockholders' Equity (Details) [Line Items]        
Authorized Common Stock That May Be Issued And Sold Under Sales Agreement $ 19,150,000      
Securities That May Be Sold Under The Agreement $ 150,000,000      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in Shares) 274,726      
Treasury Stock, Shares, Acquired (in Shares) 340,898      
Treasury Stock, Value, Acquired, Cost Method $ 4,000      
Stock Issued During Period, Shares, Employee Benefit Plan (in Shares) 37,580 91,541    
Treasury Stock [Member]        
Stockholders' Equity (Details) [Line Items]        
Treasury Stock, Shares, Acquired (in Shares) 106,911      
Treasury Stock, Value, Acquired, Cost Method $ (1,014,000)      
Stock Issued During Period, Value, Employee Benefit Plan $ 1,014,000      
Stock Issued During Period, Shares, Employee Benefit Plan (in Shares) (106,911)      
Officer [Member]        
Stockholders' Equity (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in Shares) 340,898      
Treasury Stock, Shares, Acquired (in Shares) 106,911      
Treasury Stock, Value, Acquired, Cost Method $ 1,014,000