Financial Information by Geographic Location (Details) - USD ($)	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographic location	$ 7,337,682	$ 7,725,037
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographic location	6,113,000	6,631,000
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographic location	1,116,000	939,000
Other (principally Asia Pacific Region)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographic location	$ 109,000	$ 155,000