Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended
Jul. 31, 2022	Jul. 31, 2021
Disaggregation of Revenue [Line Items]
Oncology services revenue	$ 13,745	$ 11,253
Pharmacology services
Disaggregation of Revenue [Line Items]
Oncology services revenue	12,756	10,703
Other TOS revenue
Disaggregation of Revenue [Line Items]
Oncology services revenue	948	526
Personalized oncology services
Disaggregation of Revenue [Line Items]
Oncology services revenue	$ 41	$ 24

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details