Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (5,105)	$ (10,244)
Other comprehensive gain (loss), net of tax:
Foreign currency translation adjustment	(638)	30
Unrealized gain (loss) on investments	(1)	30
Total other comprehensive gain (loss), net of tax	(639)	60
Comprehensive loss	$ (5,744)	$ (10,184)