Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2022	Oct. 31, 2021
Disaggregation of Revenue [Line Items]
Oncology services revenue	$ 14,281	$ 11,786	$ 28,026	$ 23,039
Pharmacology services
Disaggregation of Revenue [Line Items]
Oncology services revenue	13,480	11,143	26,236	21,846
Other TOS revenue
Disaggregation of Revenue [Line Items]
Oncology services revenue	731	643	1,679	1,169
Personalized oncology services
Disaggregation of Revenue [Line Items]
Oncology services revenue	$ 70	$ 0	$ 111	$ 24