Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Revenues:
Revenues	$ 32,422	$ 27,683	$ 92,904	$ 82,842
Domestic
Revenues:
Revenues	27,334	23,668	77,958	70,467
International
Revenues:
Revenues	$ 5,088	$ 4,015	$ 14,946	$ 12,375