Condensed Consolidated Statement of Changes in Stockholders' Equity - 3 months ended Jul. 31, 2016 - 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, 2016		82,270	(200)
Beginning balance at Apr. 30, 2016	$ 184,534	$ 8	$ 0	$ 437,239	$ (878)	$ (251,835)
Stock-based expense	4,066			4,066
Exercise of stock options and vested restricted stock units, Shares		751
Exercise of stock options and vested restricted stock units	(162)			(162)
Change in foreign currency translation adjustment	(638)				(638)
Change in unrealized gain on investments	(1)				(1)
Net loss	(5,105)					(5,105)
Ending balance, Shares at Jul. 31, 2016		83,021	(200)
Ending balance at Jul. 31, 2016	$ 182,694	$ 8	$ 0	$ 441,143	$ (1,517)	$ (256,940)