Major Customers (Details) (Revenue [Member], Customer Concentration Risk [Member])	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
From unrelated customers [Member] | Gaming Business [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)		11.00%
Number of major customers		1
From unrelated customers [Member] | Voting Business [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	19.00%	44.00%
Number of major customers	1	2
From related customers [Member] | Gaming Business [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	65.00%	29.00%
Number of major customers	2	2