Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Schedule of Warrant Activity (Details)

v3.5.0.2
Stock-Based Compensation - Schedule of Warrant Activity (Details) - $ / shares
12 Months Ended
Apr. 30, 2016
Apr. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]    
Warrants outstanding, beginning of period 1,102,758 161,925
Warrants, issued 16,667 940,833
Warrants, exchanged (881,800)  
Warrants outstanding, end of period 207,625 1,102,758
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value    
Weighted average exercise price of warrants outstanding, beginning of period $ 10.56 $ 24.27
Weighted average exercise price, issued 7.50  
Weighted average exercise price, exchanged 8.10 7.88
Weighted average exercise price, expired 7.50  
Weighted average exercise price of warrants outstanding, end of period $ 1.24 $ 10.56
Share-based Compensation Arrangement by Share-based Compensation-based Payment Award, Equity Instruments Other than Options, Weighted Average Remaining Contractual Life    
Weighted average remaining contractual life in years 1 year 3 months 4 years 1 month