Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Apr. 30, 2023 USD ($) segment	Apr. 30, 2022 USD ($)	Apr. 30, 2021 USD ($)
Property, Plant and Equipment [Line Items]
Cash	$ 10,118,000	$ 9,007,000
Cash equivalents	0	0
Net income	(5,335,000)	548,000
Accumulated deficit	77,317,000	71,982,000
Working capital	(2,300,000)
Asset impairment	$ 807,000	0
Number of reportable segments | segment	1
Impairment of goodwill	$ 0	0
Unrecognized tax benefits	181,000	181,000	$ 181,000
Income tax penalties and interest expense	0	0
Provision for (benefit) from income tax	$ 68,000	35,000
Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful life	7 years
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	$ 0	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	0
Liabilities, fair value	$ 0	$ 0