Summary of Significant Accounting Policies - Product Warranty (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Apr. 30, 2015 |
Apr. 30, 2014 |
Apr. 30, 2013 |
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| Summary Of Significant Accounting Policies - Product Warranty Details | |||
| Balance beginning of year | $ 69,000 | $ 69,000 | $ 79,000 |
| Charges to costs and expenses | 11,000 | 9,000 | 14,000 |
| Deductions | (70,000) | (9,000) | (24,000) |
| Balance end of year | $ 10,000 | $ 69,000 | $ 69,000 |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Represents the aggregate decrease in the liability related to payments to satisfy claims for standard and extended product warranties. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Represents the aggregate increase in the liability for accruals related to standard and extended product warranties issued during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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