UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Income Statement [Abstract]
Oncology services revenue	$ 11,786	$ 10,117	$ 23,039	$ 19,664
Costs and operating expenses:
Cost of oncology services	5,609	5,644	11,005	10,980
Research and development	2,299	1,650	4,603	3,247
Sales and marketing	1,640	1,348	3,214	2,556
General and administrative	1,975	1,468	4,129	2,850
Total costs and operating expenses	11,523	10,110	22,951	19,633
Income from operations	263	7	88	31
Other income	26	9	43	73
Income before provision for income taxes	289	16	131	104
Provision for income taxes	12	15	26	28
Net income	$ 277	$ 1	$ 105	$ 76
Net income per common share outstanding
Net income (loss) per common share outstanding, basic (in dollars per share)	$ 0.02	$ 0	$ 0.01	$ 0.01
Net income (loss) per common share outstanding, diluted (in dollars per share)	$ 0.02	$ 0	$ 0.01	$ 0.01
Weighted average common shares outstanding
Weighted average common shares outstanding, basic (in shares)	13,428,508	13,064,191	13,145,930	12,811,921
Weighted average common shares outstanding, diluted (in shares)	14,549,136	15,062,103	14,213,450	14,563,060
Revenue, Product and Service [Extensible List]	Service [Member]	Service [Member]	Service [Member]	Service [Member]
Cost, Product and Service [Extensible List]	Service [Member]	Service [Member]	Service [Member]	Service [Member]