Condensed Consolidated Statements of Changes in Stockholders' Equity - 3 months ended Jul. 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	4,049			4,049
Issuance of restricted stock awards, Shares		54
Exercise of stock options and vested restricted stock units, Shares		334
Exercise of stock options and vested restricted stock units	368			368
Change in foreign currency translation adjustment	30				30
Change in unrealized gain on investments	30				30
Net loss applicable to common stockholders	(10,244)					(10,244)
Ending balance, Shares at Jul. 31, 2015		80,734	(200)
Ending balance at Jul. 31, 2015	$ 185,616	$ 8	$ 0	$ 422,926	$ (578)	$ (236,740)