Consolidated Statements of Operations (USD $)	3 Months Ended		128 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Statement Consolidated Statements Of Operations [Line Items]
REVENUE	$ 43,750	$ 159,016	$ 4,472,850
OPERATING EXPENSES
Salaries and payroll-related costs	2,081,791	1,629,423	35,141,590
General and administrative expenses	913,784	917,676	35,755,863
Research and development	3,133,014	1,576,666	54,457,389
Stock-based compensation	521,138	395,675	15,638,877
Depreciation and amortization	403,405	449,597	9,564,103
Impairment expense			1,308,047
Contingent consideration - fair value adjustments			1,421,652
TOTAL OPERATING EXPENSES	7,053,132	4,969,037	153,287,521
OPERATING LOSS	(7,009,382)	(4,810,021)	(148,814,671)
OTHER INCOME (EXPENSE)
Equity in income (loss) of unconsolidated affiliates	(138,456)	(63,557)	(1,743,004)
Impairment of investment in unconsolidated affiliates			(1,642,775)
Gain on purchase of Roche Madison			1,576,107
Gain (loss) on sale of fixed assets, net	(53,562)	18,493	(1,336,415)
Realized and unrealized gain (loss) in marketable securities			62,954
Interest income (expense), net	40,578	7,416	2,693,112
Change in value of derivatives	(3,519,579)	44,275	(5,538,564)
Gain on sale of stock in subsidiary			2,292,800
Other income (expense)	(5,331)	22,685	(753,306)
TOTAL OTHER INCOME (EXPENSE)	(3,676,350)	29,312	(4,389,091)
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(10,685,732)	(4,780,709)	(153,203,762)
Provision for income taxes
LOSS FROM CONTINUING OPERATIONS	(10,685,732)	(4,780,709)	(153,203,762)
Income (loss) from discontinued operations		(18)	(47,546,996)
Gain on disposal of discontinued operations			4,708,588
NET INCOME (LOSS) FROM DISCONTINUED OPERATIONS		(18)	(42,838,408)
NET LOSS	(10,685,732)	(4,780,727)	(196,042,170)
Net loss attributable to noncontrolling interests	57,420	166,568	19,436,849
NET LOSS ATTRIBUTABLE TO ARROWHEAD	$ (10,628,312)	$ (4,614,159)	$ (176,605,321)
NET LOSS PER SHARE ATTRIBUTABLE TO ARROWHEAD SHAREHOLDERS - BASIC AND DILUTED:	$ (0.28)	$ (0.33)
Weighted average shares outstanding - basic and diluted	37,741,743	14,113,620