Segment Information (Narrative) (Details) (USD $)	3 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Apr. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of reportable segments	2
Revenues	$ 6,662,000	$ 7,964,000
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	4,200,000	5,500,000
Long-lived assets	18,300,000		18,800,000
All Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	2,500,000	2,500,000
Long-lived assets	$ 0		$ 0