Condensed Consolidated Statements of Changes in Stockholders' Equity - 6 months ended Oct. 31, 2015 - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Treasury stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance, Shares at Apr. 30, 2015		80,346	(200)
Beginning balance at Apr. 30, 2015	$ 191,383	$ 8	$ 0	$ 418,509	$ (638)	$ (226,496)
Stock-based expense	7,958			7,958
Issuance of restricted stock awards, Shares		242
Exercise of stock options and vested restricted stock units, Shares		638
Exercise of stock options and vested restricted stock units	867			867
Shares issued under employee stock plans, shares		297
Shares issued under employee stock plans	1,298			1,298
Change in foreign currency translation adjustment	(73)				(73)
Change in unrealized gain on investments	1				1
Net loss applicable to common stockholders	(15,096)					(15,096)
Ending balance, Shares at Oct. 31, 2015		81,523	(200)
Ending balance at Oct. 31, 2015	$ 186,338	$ 8	$ 0	$ 428,632	$ (710)	$ (241,592)