Stock-Based Compensation (Tables)

9 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Awards Outstanding

The following table presents a summary of awards outstanding:

	As of June 30, 2023
	2004 Plan	2013 Plan	2021 Plan	Inducement Awards	Total
Granted and outstanding awards:
Options	68,555	1,550,951	33,838	712,454	2,365,798
Restricted stock units	—	1,889,125	1,686,766	746,175	4,322,066
Total	68,555	3,440,076	1,720,604	1,458,629	6,687,864

Share-Based Payment Arrangement, Expensed

The following table summarizes stock-based compensation expenses included in operating expenses:

	Three Months Ended June 30,				Nine Months Ended June 30,
	2023		2022		2023		2022
	(in thousands)
Research and development	8,982		8,098		26,129		23,958
General and administrative	10,965		25,292		33,820		67,739
Total	$	19,947	$	33,390	$	59,949	$	91,697

Summarized Information about Stock Options

The following table presents a summary of the stock option activity for the nine months ended June 30, 2023:

	Shares	Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding at September 30, 2022	2,721,384	$	20.73
Granted	32,151	33.03
Cancelled or expired	(43,936)	62.31
Exercised	(343,801)	6.48
Outstanding at June 30, 2023	2,365,798	$	22.20	4.4 years	$	43,813,599
Exercisable at June 30, 2023	2,188,690	$	20.28	4.2 years	$	43,480,339

Assumptions Used to Value Stock Options

The following table provides the assumptions used in the calculation of grant-date fair values of these stock options based on the Back-Scholes option pricing model:

	Nine Months Ended June 30,
	2023			2022 (5)
Expected dividend yield(1)	—			N/A
Risk-free interest rate(2)	3.69		%	N/A
Expected volatility(3)	86.4		%	N/A
Expected term (in years)(4)	6.25			N/A
Weighted average grant date fair value per share of options granted	$	24.80		N/A

(1) The dividend yield is zero as the Company currently does not pay a dividend.

(2) The risk-free interest rate is based on that of the U.S. Treasury yields with equivalent terms in effect at the time of the grant.

(3) Volatility is estimated based on volatility average of the Company’s common stock price.

(4) The expected term represents the period of time that stock options granted are expected to be outstanding, by using historical exercise patterns and post-vesting termination behavior.

(5) No options were granted during the nine months ended June 30, 2022.

Summary of Share Activity Related to RSUs

The following table summarizes the activity of the Company’s RSUs:

	Number of RSUs	Weighted- Average Grant Date Fair Value Per Share
Outstanding at September 30, 2022	4,069,431	$	62.96
Granted	1,144,594	34.27
Vested	(798,271)	53.72
Forfeited	(93,688)	54.58
Outstanding at June 30, 2023	4,322,066	$	57.45