Consolidated Statements of Operations (USD $)	3 Months Ended		116 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
REVENUE	$ 159,016	$ 23,958	$ 4,297,850
OPERATING EXPENSES
Salaries and payroll-related costs	1,629,423	1,320,693	28,021,553
General and administrative expenses	917,676	1,266,908	32,270,891
Research and development	1,576,666	769,074	44,195,414
Stock-based compensation	395,675	251,878	13,977,143
Depreciation and amortization	449,597	454,444	7,858,883
TOTAL OPERATING EXPENSES	4,969,037	4,062,997	126,323,884
OPERATING LOSS	(4,810,021)	(4,039,039)	(122,026,034)
OTHER INCOME (EXPENSE)
Equity in income (loss) of unconsolidated affiliates	(63,557)	(106,527)	(1,026,964)
Impairment of investment in unconsolidated affiliates			(1,642,775)
Gain on purchase of Roche Madison		1,576,107	1,576,107
Gain (loss) on sale of fixed assets, net	18,493		(1,187,972)
Realized and unrealized gain (loss) in marketable securities		(58,091)	62,954
Interest income (expense), net	7,416	7,875	2,757,860
Change in value of derivatives	44,275	(66,904)	3,325,679
Gain on sale of stock in subsidiary			2,292,800
Other income	22,685		272,685
TOTAL OTHER INCOME	29,312	1,352,461	6,430,374
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(4,780,709)	(2,686,579)	(115,595,660)
Provision for income taxes
LOSS FROM CONTINUING OPERATIONS	(4,780,709)	(2,686,579)	(115,595,660)
Income (loss) from discontinued operations	(18)	(220)	(47,546,660)
Gain on disposal of discontinued operations			4,708,588
NET INCOME (LOSS) FROM DISCONTINUED OPERATIONS	(18)	(220)	(42,838,072)
NET LOSS	(4,780,727)	(2,686,799)	(158,433,732)
Net (income) loss attributable to noncontrolling interests	166,568	201,294	18,985,853
NET LOSS ATTRIBUTABLE TO ARROWHEAD	$ (4,614,159)	$ (2,485,505)	$ (139,447,879)
Earnings per share-basic and diluted:
Loss from continuing operations attributable to Arrowhead common shareholders	$ (0.33)	$ (0.25)
Income from discontinued operations attributable to Arrowhead common shareholders
Net loss attributable to Arrowhead shareholders	$ (0.33)	$ (0.25)
Weighted average shares outstanding-basic and diluted	14,113,620	10,121,069