Stockholders Equity - Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Apr. 30, 2015	Apr. 30, 2014
Number of Options
Beginning balance	7,091	10,829
Options granted	939	2,092
Options exercised	(1,246)	(3,360)
Options forfeited	(1,691)	(2,470)
Ending balance	5,093	7,091
Options vested and expected to vest at April 30, 2015	4,977
Options vested and exercisable as of April 30, 2015	2,891
Weighted Average Exercise Price
Beginning balance	$ 7.74	$ 6.83
Options granted	7.31	8.32
Options exercised	4.18	3.34
Options forfeited	9.85	10.22
Ending balance	7.83	$ 7.74
Options vested and expected to vest at April 30, 2015	7.81
Options vested and exercisable as of April 30, 2015	$ 7.60
Weighted Average Remaining Contractual Term (in Years)
Balance as of April 30, 2014	7 years	7 years 7 days
Options vested and expected to vest at April 30, 2015	6 years 11 months 16 days
Options vested and exercisable as of April 30, 2015	5 years 10 months 21 days
Aggregate Intrinsic Value
Balance as of April 30, 2014	$ 1,590	$ 6,264
Options vested and expected to vest at April 30, 2015	1,590
Options vested and exercisable as of April 30, 2015	$ 1,587