XML 61 R49.htm IDEA: XBRL DOCUMENT v3.5.0.1
Shareholders' Equity - Summary of Stock Option Activity and Related Information for Stock Options Granted, Options Outstanding and Exercisable (Details) - Stock Options
 12 Months Ended
Apr. 30, 2016
$ / shares
shares
2010 Stock Plan  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 197,332
Options outstanding - exercise price (in dollars per share) | $ / shares $ 24.55
Options exercisable (in shares) | shares 85,332
Options exercisable - exercise price (in dollars per share) | $ / shares $ 17.46
2010 Stock Plan | $10.55  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 5,333
Options outstanding - exercise price (in dollars per share) | $ / shares $ 10.70
Options outstanding - avg remaining life 5 years 3 months 9 days
Options exercisable (in shares) | shares 5,333
Options exercisable - exercise price (in dollars per share) | $ / shares $ 10.70
Options exercisable - avg. remaining life 5 years 3 months 9 days
2010 Stock Plan | $8.64  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 30,666
Options outstanding - exercise price (in dollars per share) | $ / shares $ 8.64
Options outstanding - avg remaining life 6 years 3 months 4 days
Options exercisable (in shares) | shares 30,666
Options exercisable - exercise price (in dollars per share) | $ / shares $ 8.64
Options exercisable - avg. remaining life 6 years 3 months 4 days
2010 Stock Plan | $17.27  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 73,333
Options outstanding - exercise price (in dollars per share) | $ / shares $ 17.27
Options outstanding - avg remaining life 7 years 3 months 8 days
Options exercisable (in shares) | shares 33,333
Options exercisable - exercise price (in dollars per share) | $ / shares $ 17.27
Options exercisable - avg. remaining life 7 years 3 months 8 days
2010 Stock Plan | $37.01  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 88,000
Options outstanding - exercise price (in dollars per share) | $ / shares $ 37.01
Options outstanding - avg remaining life 8 years 3 months 20 days
Options exercisable (in shares) | shares 16,000
Options exercisable - exercise price (in dollars per share) | $ / shares $ 37.01
Options exercisable - avg. remaining life 8 years 3 months 20 days
2007 Stock Plan  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 79,666
Options outstanding - exercise price (in dollars per share) | $ / shares $ 28.91
Options exercisable (in shares) | shares 31,833
Options exercisable - exercise price (in dollars per share) | $ / shares $ 25.52
2007 Stock Plan | $10.55  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 5,000
Options outstanding - exercise price (in dollars per share) | $ / shares $ 10.55
Options outstanding - avg remaining life 4 years 3 months 5 days
Options exercisable (in shares) | shares 5,000
Options exercisable - exercise price (in dollars per share) | $ / shares $ 10.55
Options exercisable - avg. remaining life 4 years 3 months 5 days
2007 Stock Plan | $8.64  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 4,166
Options outstanding - exercise price (in dollars per share) | $ / shares $ 8.64
Options outstanding - avg remaining life 6 years 3 months 4 days
Options exercisable (in shares) | shares 4,166
Options exercisable - exercise price (in dollars per share) | $ / shares $ 8.64
Options exercisable - avg. remaining life 6 years 3 months 4 days
2007 Stock Plan | $17.27  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 20,000
Options outstanding - exercise price (in dollars per share) | $ / shares $ 17.27
Options outstanding - avg remaining life 7 years 3 months 8 days
Options exercisable (in shares) | shares 5,834
Options exercisable - exercise price (in dollars per share) | $ / shares $ 17.27
Options exercisable - avg. remaining life 7 years 3 months 8 days
2007 Stock Plan | $37.01  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Options outstanding (in shares) | shares 50,500
Options outstanding - exercise price (in dollars per share) | $ / shares $ 37.01
Options outstanding - avg remaining life 8 years 3 months 20 days
Options exercisable (in shares) | shares 16,833
Options exercisable - exercise price (in dollars per share) | $ / shares $ 37.01
Options exercisable - avg. remaining life 8 years 3 months 20 days