Financial Information by Geographic Location (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Oct. 31, 2016 |
Oct. 31, 2015 |
Oct. 31, 2016 |
Oct. 31, 2015 |
|
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||||
| Revenues by geographic location | $ 4,679,000 | $ 6,051,000 | $ 9,594,000 | $ 13,388,000 |
| United States | ||||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||||
| Revenues by geographic location | 3,432,000 | 5,108,000 | 6,694,000 | 11,220,000 |
| Europe | ||||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||||
| Revenues by geographic location | 840,000 | 879,000 | 1,983,000 | 1,995,000 |
| Other (principally Asia Pacific Region) | ||||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||||
| Revenues by geographic location | $ 407,000 | $ 64,000 | $ 917,000 | $ 173,000 |