Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (55)	$ (4,134)	$ (2,371)	$ (9,239)
Other comprehensive gain (loss), net of tax:
Foreign currency translation adjustment	9	(488)	292	(1,126)
Unrealized gain (loss) on investments	35	(1)	21	(2)
Total other comprehensive gain (loss), net of tax	44	(489)	313	(1,128)
Comprehensive loss	$ (11)	$ (4,623)	$ (2,058)	$ (10,367)