UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Income Statement [Abstract]
Oncology services revenue	$ 11,253	$ 9,547
Costs and operating expenses:
Cost of oncology services	5,396	5,336
Research and development	2,304	1,597
Sales and marketing	1,574	1,208
General and administrative	2,154	1,382
Total costs and operating expenses	11,428	9,523
Income (loss) from operations	(175)	24
Other income	17	64
Income (loss) before provision for income taxes	(158)	88
Provision for income taxes	14	13
Net income (loss)	$ (172)	$ 75
Net income (loss) per common share outstanding
Net income (loss) per common share outstanding, basic (in dollars per share)	$ (0.01)	$ 0.01
Net income (loss) per common share outstanding, diluted (in dollars per share)	$ (0.01)	$ 0.01
Weighted average common shares outstanding
Weighted average common shares outstanding, basic (in shares)	13,401,929	12,727,275
Weighted average common shares outstanding, diluted (in shares)	13,401,929	14,231,641
Revenue, Product and Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember
Cost, Product and Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember