Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
CURRENT ASSETS
Cash and cash equivalents	$ 372,377	$ 143,583
Accounts receivable	955	845
Prepaid expenses	6,639	4,250
Other current assets	1,845	1,782
Marketable securities	125,793	85,020
Short term investments (held to maturity)	79,148	86,890
TOTAL CURRENT ASSETS	586,757	322,370
Property and equipment, net	39,400	30,881
Intangible assets, net	14,513	15,363
Long term investments (held to maturity)	97,490	137,487
Right-of-use assets	18,370	16,138
Other assets	265	265
TOTAL ASSETS	756,795	522,504
CURRENT LIABILITIES
Accounts payable	5,299	6,829
Accrued expenses	12,862	5,389
Accrued payroll and benefits	2,859	8,061
Lease liabilities	1,272	1,095
Deferred revenue	144,879	19,291
Other current liabilities	17	16
TOTAL CURRENT LIABILITIES	167,188	40,681
LONG-TERM LIABILITIES
Lease liabilities, net of current portion	22,528	20,044
Deferred revenue, net of current portion	121,530
TOTAL LONG-TERM LIABILITIES	144,058	20,044
Commitments and contingencies (Note 7)
Arrowhead Pharmaceuticals, Inc. stockholders’ equity:
Common stock, $0.001 par value; 145,000 shares authorized; 104,020 and 102,376 shares issued and outstanding as of March 31, 2021 and September 30, 2020, respectively	196	195
Additional paid-in capital	996,645	965,410
Accumulated other comprehensive income	102	18
Accumulated deficit	(551,394)	(503,844)
TOTAL STOCKHOLDERS’ EQUITY	445,549	461,779
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 756,795	$ 522,504