Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		9 Months Ended		110 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012
Consolidated Statements of Operations [Abstract]
REVENUE	$ 47,917		$ 103,125	$ 296,139	$ 4,095,084
OPERATING EXPENSES
Salaries and payroll - related costs	1,654,915	354,223	4,992,671	1,087,714	24,969,880
General and administrative expenses	3,137,368	637,145	5,335,191	2,075,853	30,249,083
Research and development	1,219,236	365,618	3,347,002	2,768,130	40,574,287
Stock-based compensation	415,920	346,707	837,188	1,078,951	13,177,252
Depreciation & amortization	423,414	66,472	1,301,806	203,041	6,962,117
TOTAL OPERATING EXPENSES	6,850,853	1,770,165	15,813,858	7,213,689	115,932,619
OPERATING LOSS	(6,802,936)	(1,770,165)	(15,710,733)	(6,917,550)	(111,837,535)
OTHER INCOME (EXPENSE)
Equity in income (loss) of unconsolidated affiliates	(34,573)	(70,366)	(205,361)	(96,367)	(928,614)
Impairment of investment in unconsolidated affiliates	(1,455,775)		(1,455,775)		(1,455,775)
Gain on sale of stock in subsidiary					2,292,800
Gain on purchase of Roche Madison			1,576,107		1,576,107
Gain (loss) on sale of property and equipment, net	(876,277)		(909,761)		(1,036,849)
Realized and unrealized gain (loss) in marketable securities		(498,406)	(58,091)	(138,486)	62,954
Interest income (expense), net	14,436	20,531	27,326	70,815	2,741,804
Change in value of derivatives	915,387	373,734	226,339	1,243,156	3,120,851
Other income					250,000
TOTAL OTHER INCOME (EXPENSE)	(1,436,802)	(174,507)	(799,216)	1,079,118	6,623,278
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(8,239,738)	(1,944,672)	(16,509,949)	(5,838,432)	(105,214,257)
Provision for income taxes
LOSS FROM CONTINUING OPERATIONS	(8,239,738)	(1,944,672)	(16,509,949)	(5,838,432)	(105,214,257)
Income (loss) from discontinued operations	677	(68,742)	(25)	1,373,758	(47,546,587)
Gain on disposal of discontinued operations				3,919,213	4,708,588
NET INCOME (LOSS) FROM DISCONTINUED OPERATIONS	677	(68,742)	(25)	5,292,971	(42,837,999)
NET INCOME (LOSS)	(8,239,061)	(2,013,414)	(16,509,974)	(545,461)	(148,052,256)
Net (income) loss attributable to noncontrolling interests	247,551	193,497	697,727	193,099	18,532,217
NET INCOME (LOSS) ATTRIBUTABLE TO ARROWHEAD	$ (7,991,510.17)	$ (1,819,917)	$ (15,812,247)	$ (352,362)	$ (129,520,039)
Earnings per share - basic:
Loss from continuing operations attributable to Arrowhead common shareholders	$ (0.71)	$ (0.24)	$ (1.48)	$ (0.79)
Income (loss) from discontinued operations attributable to Arrowhead common shareholders		$ (0.01)		$ 0.74
Net income (loss) attributable to Arrowhead shareholders	$ (0.71)	$ (0.25)	$ (1.48)	$ (0.05)
Weighted average shares outstanding	11,238,291	7,182,628	10,672,390	7,180,403
Earnings per share - diluted:
Income (loss) from continuing operations attributable to Arrowhead common shareholders	$ (0.71)	$ (0.24)	$ (1.48)	$ (0.71)
Income (loss) from discontinued operations attributable to Arrowhead common shareholders		$ (0.01)		$ 0.67
Net income (loss) attributable to Arrowhead shareholders	$ (0.71)	$ (0.25)	$ (1.48)	$ (0.04)
Weighted average shares outstanding	11,238,291	7,182,628	10,672,390	7,856,795