UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (shares) at Apr. 30, 2021		13,414,066
Beginning balance at Apr. 30, 2021	$ 7,428	$ 13	$ 79,945	$ (72,530)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	280		280
Issuance of common stock on exercise of stock options (in shares)		1,000
Issuance of common stock on exercise of stock options	2		2
Net loss	(172)			(172)
Ending balance (shares) at Jul. 31, 2021		13,415,066
Ending balance at Jul. 31, 2021	$ 7,538	$ 13	80,227	(72,702)
Beginning balance (shares) at Apr. 30, 2022	13,522,441	13,522,441
Beginning balance at Apr. 30, 2022	$ 9,096	$ 14	81,064	(71,982)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	206		206
Net loss	$ (319)			(319)
Ending balance (shares) at Jul. 31, 2022	13,522,441	13,522,441
Ending balance at Jul. 31, 2022	$ 8,983	$ 14	$ 81,270	$ (72,301)