Stock-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Awards Outstanding

The following table presents a summary of awards outstanding:

	As of March 31, 2023
	2004 Plan	2013 Plan	2021 Plan	Inducement Awards	Total
Granted and outstanding awards:
Options	173,983	1,629,457	35,151	743,726	2,582,317
Restricted stock units	—	1,889,500	1,701,968	738,875	4,330,343
Total	173,983	3,518,957	1,737,119	1,482,601	6,912,660

Summarized Information about Stock Options

The following table presents a summary of the stock option activity for the six months ended March 31, 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	(25,581)	58.07
Exercised	(145,637)	7.50
Outstanding at March 31, 2023	2,582,317	$	21.26	4.5 years	$	30,107,439
Exercisable at March 31, 2023	2,348,193	$	18.75	4.2 years	$	30,100,306

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:

	Six Months Ended March 31,
	2023			2022
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 (5)	$	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 six months ended March 31, 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	1,098,544	34.67
Vested	(763,132)	54.20
Forfeited	(74,500)	57.28
Outstanding at March 31, 2023	4,330,343	$	57.62