Consolidated Statements of Changes in Convertible Preferred Shares and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
Series A Convertible Preferred Stock [Member]
Stock issuance costs		$ 6
Series B Convertible Preferred Stock [Member]
Stock issuance costs	$ 186