Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Product Warranty (Details)

v3.5.0.2
Summary of Significant Accounting Policies - Product Warranty (Details) - USD ($)
12 Months Ended
Apr. 30, 2016
Apr. 30, 2015
Accounting Policies [Abstract]    
Balance beginning of year $ 10,000 $ 69,000
Charges to costs and expenses 0 11,000
Deductions 0 (70,000)
Balance end of year $ 10,000 $ 10,000