Revenue Recognition - Summary of Net Sales Transferred to Customers at a Point in Time and Over Time (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Disaggregation of Revenue [Line Items]
Total	$ 40,633	$ 33,339	$ 119,157	$ 108,762
Over Time
Disaggregation of Revenue [Line Items]
Total	39,342	32,471	115,371	106,072
Point in Time
Disaggregation of Revenue [Line Items]
Total	1,291	868	3,786	2,690
Domestic
Disaggregation of Revenue [Line Items]
Total	29,531	25,066	89,128	83,896
Domestic | Over Time
Disaggregation of Revenue [Line Items]
Total	28,240	24,198	85,342	81,206
Domestic | Point in Time
Disaggregation of Revenue [Line Items]
Total	1,291	868	3,786	2,690
International
Disaggregation of Revenue [Line Items]
Total	11,102	8,273	30,029	24,866
International | Over Time
Disaggregation of Revenue [Line Items]
Total	11,102	8,273	30,029	24,866
International | Point in Time
Disaggregation of Revenue [Line Items]
Total	$ 0	$ 0	$ 0	$ 0