Stock-Based Compensation (Tables)

12 Months Ended

Apr. 30, 2022

Share-based Payment Arrangement [Abstract]

Schedule of Fair Value of Share-based Awards Measured with Weighted-Average Assumptions

The fair value of the share-based awards was measured with the following weighted-average assumptions for the fiscal years ended April 30:

	2022	2021	2020
Risk-free interest rate	1.08%	0.47%	2.06%
Expected life of the options	6.25 years	6.25 years	6.25 years
Expected volatility of the underlying stock	85.4%	81.7%	81.1%
Expected dividend rate	0%	0%	0%

Schedule of Stock-Based Compensation Expense

Stock-based compensation was reflected in the Company’s consolidated statement of operations and comprehensive loss as follows (in thousands):

	Year ended April 30,
	2022		2021		2020
Research and development	$	5,189	$	3,174	$	1,944
General and administrative		5,897		3,944		2,504
Total stock-based compensation expense	$	11,086	$	7,118	$	4,448

Summary of Option Activity

A summary of option activity for the year ended April 30, 2022 is presented below:

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life		Aggregate Intrinsic Value
Outstanding at May 1, 2021		2,836,598		$	13.22		7.60	$	33,514
Options Exercised		(114,199	)		8.49
Options Granted		1,007,000			23.73
Options Cancelled		(136,378	)		18.86
Outstanding at April 30, 2022		3,593,021		$	16.10		7.26	$	6,430
Exercisable at April 30, 2022		2,067,684		$	13.61		6.51	$	5,454
Vested and expected to vest at April 30, 2022		3,593,021		$	16.10		7.26	$	6,430