XML 49 R44.htm IDEA: XBRL DOCUMENT v2.4.0.8
Maintenance Contracts (Details) (USD $)
3 Months Ended 6 Months Ended
Oct. 31, 2013
Oct. 31, 2012
Oct. 31, 2013
Oct. 31, 2012
Apr. 30, 2013
Maintenance Contracts [Abstract]          
Beginning balance $ 7,579,000 $ 7,153,000 $ 8,861,000 $ 8,302,000  
Revenue recognized during period (3,494,000) (4,346,000) (7,039,000) (8,028,000)  
New maintenance contracts 2,518,000 3,795,000 4,781,000 6,328,000  
Ending balance 6,603,000 6,602,000 6,603,000 6,602,000  
Long-term deferred maintenance revenue $ 700,000   $ 700,000   $ 800,000