Stock-Based Compensation (Stock-Based Compensation Expense Allocated) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,177	$ 961
Cost of Sales and Distribution [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	349	299
Selling and Marketing Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	319	(21)
General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 509	$ 683