Investments (Details) - USD ($) $ in Thousands	Jul. 30, 2022	Apr. 30, 2022
Short-term investments:
Total short-term investments	$ 12,655	$ 24,716
Long-term investments:
Equity Method Investments.	17,707	15,433
Total long-term investments	17,707	15,433
Investment in limited partnership fund
Long-term investments:
Equity Method Investments.	17,707	15,433
Available-for-sale securities.
Short-term investments:
Total short-term investments	12,655	24,716
Available-for-sale securities. | Municipal securities
Short-term investments:
Total short-term investments	7,664	19,725
Available-for-sale securities. | U.S. government securities
Short-term investments:
Total short-term investments	$ 4,991	$ 4,991