UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in 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 income (loss)	(172)			(172)
Ending balance (in shares) at Jul. 31, 2021		13,415,066
Ending balance at Jul. 31, 2021	7,538	$ 13	80,227	(72,702)
Beginning balance (in 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]
Net income (loss)	105
Ending balance (in shares) at Oct. 31, 2021		13,496,144
Ending balance at Oct. 31, 2021	8,071	$ 14	80,482	(72,425)
Beginning balance (in shares) at Jul. 31, 2021		13,415,066
Beginning balance at Jul. 31, 2021	7,538	$ 13	80,227	(72,702)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	134		134
Issuance of common stock on exercise of stock options (in shares)		81,078
Issuance of common stock on exercise of stock options	122	$ 1	121
Net income (loss)	277			277
Ending balance (in shares) at Oct. 31, 2021		13,496,144
Ending balance at Oct. 31, 2021	$ 8,071	$ 14	80,482	(72,425)
Beginning balance (in shares) at Apr. 30, 2022	13,558,650	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 income (loss)	(319)			(319)
Ending balance (in shares) at Jul. 31, 2022		13,522,441
Ending balance at Jul. 31, 2022	$ 8,983	$ 14	81,270	(72,301)
Beginning balance (in shares) at Apr. 30, 2022	13,558,650	13,522,441
Beginning balance at Apr. 30, 2022	$ 9,096	$ 14	81,064	(71,982)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (335)
Ending balance (in shares) at Oct. 31, 2022	13,558,650	13,558,650
Ending balance at Oct. 31, 2022	$ 9,172	$ 14	81,475	(72,317)
Beginning balance (in shares) at Jul. 31, 2022		13,522,441
Beginning balance at Jul. 31, 2022	8,983	$ 14	81,270	(72,301)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	119		119
Issuance of common stock on exercise of stock options (in shares)		36,209
Issuance of common stock on exercise of stock options	86		86
Net income (loss)	$ (16)			(16)
Ending balance (in shares) at Oct. 31, 2022	13,558,650	13,558,650
Ending balance at Oct. 31, 2022	$ 9,172	$ 14	$ 81,475	$ (72,317)