Property and Equipment - Narrative (Details)	3 Months Ended		9 Months Ended
	Jan. 31, 2024 USD ($)	Jan. 31, 2023 USD ($)	Jan. 31, 2024 USD ($) asset	Jan. 31, 2023 USD ($)	Apr. 30, 2023 USD ($)
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 481,000	$ 575,000	$ 1,400,000	$ 1,700,000
Depreciation and amortization, excluding finance leases	445,000	540,000	1,300,000	1,600,000
Finance lease, asset, gross	1,000,000		1,000,000		$ 1,000,000
Finance lease, depreciation and amortization	36,000	35,000	$ 108,000	99,000
Number of assets disposed | asset			2
Loss on disposal of equipment			$ 81,000	0
Payments to acquire assets			947,000	2,112,000
Accumulated depreciation and amortization	9,961,000		9,961,000		8,630,000
Servicing asset	1,900,000		1,900,000
Servicing asset at fair value, amount					$ 807,000
Hosting arrangement, amortization expense	$ 0	157,000	$ 0	471,000
Finance lease, weighted average remaining lease term	2 years 9 months 29 days		2 years 9 months 29 days
2023 Finance Lease
Property, Plant and Equipment [Line Items]
Finance lease costs	$ 368,000			368,000
Present value of minimum future obligations interest rate	3.50%
Finance lease, amortization	$ 17,800	17,100	$ 52,800	45,100
2022 Finance Lease
Property, Plant and Equipment [Line Items]
Finance lease costs	$ 370,000			370,000
Present value of minimum future obligations interest rate	3.25%
Finance lease, amortization	$ 18,700	$ 18,000	$ 55,600	$ 54,000
Capitalized software development costs
Property, Plant and Equipment [Line Items]
Useful lives	3 years		3 years
Laboratory equipment
Property, Plant and Equipment [Line Items]
Loss on disposal of equipment			$ 66,000
Payments to acquire assets			128,000
Accumulated depreciation and amortization	$ 62,000		62,000
Computer equipment and software
Property, Plant and Equipment [Line Items]
Loss on disposal of equipment			15,000
Payments to acquire assets			33,000
Accumulated depreciation and amortization	$ 18,000		$ 18,000
Minimum
Property, Plant and Equipment [Line Items]
Useful lives	3 years		3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful lives	9 years		9 years