UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Income Statement [Abstract]
Oncology services revenue	$ 10,117	$ 7,625	$ 19,664	$ 14,362
Costs and operating expenses:
Cost of oncology services	5,644	3,881	10,980	7,633
Research and development	1,650	1,341	3,247	2,644
Sales and marketing	1,348	977	2,556	1,847
General and administrative	1,468	1,135	2,850	2,561
Total costs and operating expenses	10,110	7,334	19,633	14,685
Income (loss) from operations	7	291	31	(323)
Other income	9	27	73	15
Income (loss) before provision for income taxes	16	318	104	(308)
Provision for income taxes	15	11	28	26
Net income (loss)	$ 1	$ 307	$ 76	$ (334)
Net income (loss) per common share outstanding
Net income (loss) per common share outstanding, basic (in dollars per share)	$ 0	$ 0.03	$ 0.01	$ (0.03)
Net income (loss) per common share outstanding, diluted (in dollars per share)	$ 0	$ 0.02	$ 0.01	$ (0.03)
Weighted average common shares outstanding
Weighted average common shares outstanding, basic (in shares)	13,064,191	11,619,686	12,811,921	11,619,569
Weighted average common shares outstanding, diluted (in shares)	15,062,103	12,964,792	14,563,060	11,619,569
Revenue, Product and Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember
Cost, Product and Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember