UNAUDITED CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (shares) at Apr. 30, 2019		11,619,538
Beginning balance at Apr. 30, 2019	$ 2,238	$ 12	$ 72,924	$ (70,698)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	131		131
Net income (loss)	(641)			(641)
Ending balance (shares) at Jul. 31, 2019		11,619,538
Ending balance at Jul. 31, 2019	1,728	$ 12	73,055	(71,339)
Beginning balance (shares) at Apr. 30, 2020		12,726,728
Beginning balance at Apr. 30, 2020	5,318	$ 13	77,978	(72,673)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 120		120
Issuance of common stock on exercise of stock options (in shares)	1,160
Issuance of common stock on exercise of stock options	$ 0
Net income (loss)	75			75
Ending balance (shares) at Jul. 31, 2020		12,727,888
Ending balance at Jul. 31, 2020	$ 5,513	$ 13	$ 78,098	$ (72,598)