UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
Income Statement [Abstract]
Revenue, Product and Service [Extensible List]	Service [Member]	Service [Member]	Service [Member]	Service [Member]
Oncology services revenue	$ 12,019	$ 12,773	$ 36,153	$ 40,799
Costs and operating expenses:
Cost, Product and Service [Extensible List]	Service [Member]	Service [Member]	Service [Member]	Service [Member]
Cost of oncology services	$ 7,849	$ 7,699	$ 22,151	$ 22,194
Research and development	2,186	3,202	7,494	8,693
Sales and marketing	1,797	1,761	5,288	5,153
General and administrative	2,764	2,569	8,305	7,494
Total costs and operating expenses	14,596	15,231	43,238	43,534
Loss from operations	(2,577)	(2,458)	(7,085)	(2,735)
Other income (loss)	58	36	(33)	9
Loss before provision for income taxes	(2,519)	(2,422)	(7,118)	(2,726)
Provision for income taxes	11	17	49	48
Net loss	$ (2,530)	$ (2,439)	$ (7,167)	$ (2,774)
Net loss per common share outstanding
Basic (in dollars per share)	$ (0.19)	$ (0.18)	$ (0.53)	$ (0.20)
Diluted (in dollars per share)	$ (0.19)	$ (0.18)	$ (0.53)	$ (0.20)
Weighted average common shares outstanding
Basic (in shares)	13,593,758	13,558,642	13,538,480	13,532,990
Diluted (in shares)	13,593,758	13,558,642	13,538,480	13,532,990