Major Customers (Details)	3 Months Ended		9 Months Ended
	Jan. 31, 2014 Customer	Jan. 31, 2013 Customer	Jan. 31, 2014 Customer	Jan. 31, 2013 Customer
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)			10.00%
Revenue [Member] | Customer Concentration Risk [Member] | From Unrelated Customers [Member] | Gaming Business [Member]
Concentration Risk [Line Items]
Number of major customers		1	1	1
Concentration risk, percentage (in hundredths)		54.00%	33.00%	21.00%
Revenue [Member] | Customer Concentration Risk [Member] | From Unrelated Customers [Member] | Voting Business [Member]
Concentration Risk [Line Items]
Number of major customers	1			1
Concentration risk, percentage (in hundredths)	22.00%			22.00%
Revenue [Member] | Customer Concentration Risk [Member] | From Related Customers [Member] | Gaming Business [Member]
Concentration Risk [Line Items]
Number of major customers	1	1	1	2
Concentration risk, percentage (in hundredths)	72.00%	30.00%	56.00%	47.00%