Consolidated Balance Sheets - USD ($)	Mar. 31, 2020	Sep. 30, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 256,650,727	$ 221,804,128
Accounts receivable	1,265,771	661,361
Prepaid expenses	3,062,333	3,317,999
Other current assets	2,536,284	2,563,435
Short term investments	50,959,058	36,899,894
TOTAL CURRENT ASSETS	314,474,173	265,246,817
Property and equipment, net	29,362,741	23,214,899
Intangible assets, net	16,213,366	17,063,580
Long term investments	190,618,075	44,175,993
Right-of-use assets	10,263,197
Other assets	144,150	144,148
TOTAL ASSETS	561,075,702	349,845,437
CURRENT LIABILITIES
Accounts payable	13,417,692	7,649,921
Accrued expenses	4,419,233	6,504,729
Accrued payroll and benefits	1,616,090	4,955,887
Lease liabilities	688,454
Deferred rent		173,952
Deferred revenue	33,174,765	77,769,629
Other current liabilities	17,263	16,561
TOTAL CURRENT LIABILITIES	53,333,497	97,070,679
LONG-TERM LIABILITIES
Lease liabilities, net of current portion	14,178,735
Deferred rent, net of current portion		3,703,364
Deferred revenue, net of current portion		5,035,142
TOTAL LONG-TERM LIABILITIES	14,178,735	8,738,506
Commitments and contingencies (Note 7)
Arrowhead Pharmaceuticals, Inc. stockholders' equity:
Common stock, $0.001 par value; 145,000,000 shares authorized; 101,748,107 and 95,506,271 shares issued and outstanding as of March 31, 2020 and September 30, 2019, respectively	194,117	187,876
Additional paid-in capital	936,353,920	664,086,155
Accumulated other comprehensive income (loss)	(629,114)	(391,624)
Accumulated deficit	(441,800,265)	(419,290,967)
Total Arrowhead Pharmaceuticals, Inc. stockholders' equity	494,118,658	244,591,440
Noncontrolling interest	(555,188)	(555,188)
TOTAL STOCKHOLDERS’ EQUITY	493,563,470	244,036,252
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 561,075,702	$ 349,845,437