CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022
Income Statement [Abstract]
Revenue, Product and Service [Extensible Enumeration]	Service [Member]	Service [Member]
Oncology services revenue	$ 53,870,000	$ 49,109,000
Costs and operating expenses:
Cost, Product and Service [Extensible Enumeration]	Service [Member]	Service [Member]
Cost of oncology services	$ 29,532,000	$ 23,632,000
Research and development	11,545,000	9,374,000
Sales and marketing	7,002,000	6,379,000
General and administrative	10,240,000	9,117,000
Asset impairment	807,000	0
Total costs and operating expenses	59,126,000	48,502,000
(Loss) income from operations	(5,256,000)	607,000
Other expense:
Other expense, net	(11,000)	(24,000)
(Loss) income before income tax expense	(5,267,000)	583,000
Provision for income tax	68,000	35,000
Net (loss) income	$ (5,335,000)	$ 548,000
Net (loss) income per common share outstanding
Net (loss) income per common share outstanding, basic (in usd per share)	$ (0.39)	$ 0.04
Net (loss) income per common share outstanding, diluted (in usd per share)	$ (0.39)	$ 0.04
Weighted average common shares outstanding
Weighted average common shares outstanding basic (in shares)	13,541,559	13,197,170
Weighted average common shares outstanding diluted (in shares)	13,541,559	14,159,799