CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Apr. 30, 2024	Apr. 30, 2023
Income Statement [Abstract]
Revenue, Product and Service [Extensible Enumeration]	Service [Member]	Service [Member]
Oncology services revenue	$ 50,155,000	$ 53,870,000
Costs and operating expenses:
Cost, Product and Service [Extensible Enumeration]	Service [Member]	Service [Member]
Cost of oncology services	$ 29,401,000	$ 29,532,000
Research and development	9,544,000	11,545,000
Sales and marketing	7,064,000	7,002,000
General and administrative	11,067,000	10,240,000
Loss on disposal of equipment	435,000	0
Asset impairment	0	807,000
Total costs and operating expenses	57,511,000	59,126,000
Loss from operations	(7,356,000)	(5,256,000)
Other income (expense):
Other income (expense), net	48,000	(11,000)
Loss before income tax expense	(7,308,000)	(5,267,000)
(Benefit) provision for income tax	(32,000)	68,000
Net loss	$ (7,276,000)	$ (5,335,000)
Net loss per common share outstanding
Net loss per common share outstanding, basic (in usd per share)	$ (0.54)	$ (0.39)
Net loss per common share outstanding, diluted (in usd per share)	$ (0.54)	$ (0.39)
Weighted average common shares outstanding
Weighted average common shares outstanding, basic (in shares)	13,547,604	13,541,559
Weighted average common shares outstanding, diluted (in shares)	13,547,604	13,541,559