Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended				6 Months Ended
	Oct. 31, 2023	Jul. 31, 2023	Oct. 31, 2022	Jul. 31, 2022	Oct. 31, 2023	Oct. 31, 2022	Apr. 30, 2023
Accounting Policies [Abstract]
Cash equivalents	$ 3,600,000				$ 3,600,000		$ 0
Cash above US insurance limit	4,300,000				4,300,000		8,700,000
Net loss	(2,071,000)	$ (2,566,000)	$ (16,000)	$ (319,000)	(4,637,000)	$ (335,000)
Net cash provided by (used in) operating activities					(3,402,000)	3,091,000
Accumulated deficit	81,954,000				81,954,000		77,317,000
Cash and cash equivalents	5,513,000				5,513,000		10,118,000
Unrecognized tax benefits	181,000				181,000		181,000
Income tax penalties and interest expense	0		0		0	0
Unrecognized tax benefits anticipated during the next 12 months	0				0
Provision for income taxes	11,000		$ 14,000		39,000	$ 31,000
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, fair value	0				0		0
Assets, fair value							0
Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, fair value	$ 0				$ 0		0
Assets, fair value							$ 0