Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Revenues:
Revenues	$ 31,211	$ 27,881	$ 60,482	$ 55,159
Domestic
Revenues:
Revenues	26,197	23,659	50,624	46,799
International
Revenues:
Revenues	$ 5,014	$ 4,222	$ 9,858	$ 8,360