Summary of Significant Accounting Policies - Calculations of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Basic and diluted net loss per share computation (dollars in thousands except per share amounts)
Net loss attributable to common stockholders	$ (1,476)	$ (6,884)
Weighted Average common shares (in shares)	10,991,105	10,684,395
Basic and diluted net loss per share (in dollars per share)	$ (0.13)	$ (0.64)