Consolidated Balance Sheets - USD ($)	Dec. 31, 2019	Sep. 30, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 461,032,249	$ 221,804,128
Accounts receivable	1,345,298	661,361
Prepaid expenses	2,733,140	3,317,999
Other current assets	1,534,344	2,563,435
Short term investments	40,969,341	36,899,894
TOTAL CURRENT ASSETS	507,614,372	265,246,817
Property and equipment, net	26,434,783	23,214,899
Intangible assets, net	16,638,473	17,063,580
Long term investments	26,329,098	44,175,993
Right-of-use assets	10,440,758
Other assets	144,150	144,148
TOTAL ASSETS	587,601,634	349,845,437
CURRENT LIABILITIES
Accounts payable	12,201,532	7,649,921
Accrued expenses	3,988,186	6,504,729
Accrued payroll and benefits	2,993,682	4,955,887
Lease liabilities	461,178
Deferred rent		173,952
Deferred revenue	54,034,129	77,769,629
Other current liabilities	16,561	16,561
TOTAL CURRENT LIABILITIES	73,695,268	97,070,679
LONG-TERM LIABILITIES
Lease liabilities, net of current portion	14,377,723
Deferred rent, net of current portion		3,703,364
Deferred revenue, net of current portion		5,035,142
TOTAL LONG-TERM LIABILITIES	14,377,723	8,738,506
Commitments and contingencies (Note 7)
Arrowhead Pharmaceuticals, Inc. stockholders' equity:
Common stock, $0.001 par value; 145,000,000 shares authorized; 101,111,797 and 95,506,271 shares issued and outstanding as of December 31, 2019 and September 30, 2019, respectively	193,481	187,876
Additional paid-in capital	922,050,595	664,086,155
Accumulated other comprehensive income (loss)	(195,550)	(391,624)
Accumulated deficit	(421,964,695)	(419,290,967)
Total Arrowhead Pharmaceuticals, Inc. stockholders' equity	500,083,831	244,591,440
Noncontrolling interest	(555,188)	(555,188)
TOTAL STOCKHOLDERS’ EQUITY	499,528,643	244,036,252
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 587,601,634	$ 349,845,437