Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation and Stock Incentive Plans (Details Textual)

v2.4.0.6
Stock-Based Compensation and Stock Incentive Plans (Details Textual) (USD $)
0 Months Ended 3 Months Ended 12 Months Ended
May 31, 2012
Apr. 30, 2013
Apr. 30, 2012
Jan. 31, 2012
Jul. 20, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized         2,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Description   Option awards may be granted to employees at an exercise price per share of not less than 100% of the fair market value per common share on the date of the grant.      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 875,000        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number   437,500      
Stock Option Value Per Share   $ 3.78      
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period   2 years 1 month 6 days      
Fair Value Assumptions, Risk Free Interest Rate   1.22%      
Stock-based compensation expense   $ 1,113,000 $ 1,028,000    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value   3,300,000      
Share Based Compensation Arrangement By Share Based Payment Award Maximum Number Of Shares Per Participant   1,250,000   500,000  
Share Based Compensation Arrangement By Share Based Payment Award Vesting Limit Per Participant   500,000      
Stock Options [Member]
         
Stock-based compensation expense   $ 400,000