Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended
	Jul. 31, 2023	Jul. 31, 2022	Apr. 30, 2023
Accounting Policies [Abstract]
Cash equivalents	$ 4,100,000		$ 0
Cash above US insurance limit	4,700,000		8,700,000
Net loss	(2,566,000)	$ (319,000)
Net cash used in operating activities	(3,991,000)	(195,000)
Accumulated deficit	79,883,000		77,317,000
Cash and cash equivalents	4,869,000		10,118,000
Unrecognized tax benefits	181,000		181,000
Income tax penalties and interest expense	0	0
Unrecognized tax benefits anticipated during the next 12 months	0
Provision for income taxes	28,000	$ 17,000
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value			0
Liabilities, fair value	0		0
Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value			0
Liabilities, fair value	$ 0		$ 0