CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Share-based compensation expense included in costs and expenses:
Share-based compensation expense	$ 22,500	$ 7,700	$ 4,700
Cost of revenue
Share-based compensation expense included in costs and expenses:
Share-based compensation expense	1,704	1,220	978
Selling and Marketing Expense
Share-based compensation expense included in costs and expenses:
Share-based compensation expense	4,250	1,869	1,122
Research and Development Expense
Share-based compensation expense included in costs and expenses:
Share-based compensation expense	3,126	1,326	731
General and Administrative Expense
Share-based compensation expense included in costs and expenses:
Share-based compensation expense	$ 13,373	$ 3,295	$ 1,850