Stock-Based Compensation (Tables)

3 Months Ended

Dec. 31, 2025

Share-Based Payment Arrangement [Abstract]

Schedule of Awards Outstanding

The following table presents a summary of awards outstanding attributable to Arrowhead Pharmaceuticals, Inc.:

	December 31, 2025
	2013 Plan	2021 Plan	Inducement Awards	Total
Granted and outstanding awards:
Options	621,592	32,151	456,610	1,110,353
Restricted stock units	1,100,000	4,047,992	753,405	5,901,397
Total	1,721,592	4,080,143	1,210,015	7,011,750

Schedule of Stock-Based Compensation Expenses

The following table summarizes stock-based compensation expenses included in operating expenses attributable to Arrowhead Pharmaceuticals, Inc.:

	Three Months Ended December 31,
	2025		2024
	(in thousands)
Research and development	$	6,376	$	6,846
General and administrative	13,214		7,329
Total	$	19,590	$	14,175

Schedule of Stock Option Activity

The following table presents a summary of the stock option activity for the three months ended December 31, 2025:

	Shares	Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding at September 30, 2025	1,407,035	$	28.90
Granted	—	—
Cancelled or expired	—	—
Exercised	(296,682)	17.19
Outstanding at December 31, 2025	1,110,353	$	32.03	3.5	$	38,383,567
Exercisable at December 31, 2025	1,110,353	$	32.03	3.5	$	38,384,567

Schedule 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, 2025	5,810,351	$	36.97
Granted	826,288	62.88
Vested	(704,406)	57.34
Forfeited	(30,836)	22.89
Outstanding at December 31, 2025	5,901,397	$	38.25