XML 58 R43.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation (Narrative) (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Jan. 31, 2018
Jan. 31, 2017
Jan. 31, 2018
Jan. 31, 2017
Apr. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock-based compensation expense $ 897 $ 827 $ 2,506 $ 2,477  
Liability for payment of the RSTUs $ 46,712   $ 46,712   $ 36,162
Employee Service-Based RSUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Awarded in period (in shares)     22,250    
Employee Performance-Based RSUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Awarded in period (in shares)     33,080    
Common stock issuable per RSU granted (in shares)     1    
Employee and Non Employee Director Service-Based RSUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Granted non-statutory stock options to key employees (in shares)        
RSUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period, years        
Non-Employee Service-Based Restricted Stock Units [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period, years        
Employee Performance-Based RSTUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted stock units non vested grants (in shares)     4,496    
Employee Service-Based RSTUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted stock units non vested grants (in shares)     2,519    
RSTUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period, years     3 years    
Stock-based compensation expense $ 600 $ 100 $ 1,000 $ 300  
Liability for payment of the RSTUs $ 1,600   $ 1,600   $ 1,500
Cliff Vest [Member] | RSUs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period, years     3 years