Inventories (Tables)

12 Months Ended

Apr. 30, 2018

Inventory Disclosure [Abstract]

Summary of Inventories

Inventories consisted of the following at April 30:

$ in thousands	2018		2017
Finished goods	$	4,751	$	3,179
Work-in-process		2,278		1,950
Materials and components		10,633		9,806
Total inventories	$	17,662	$	14,935