Consolidated Statements of Operations (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
REVENUE	$ 175,000	$ 290,266	$ 146,875
OPERATING EXPENSES
Research and development	23,138,050	8,705,627	5,391,463
Salaries and payroll-related costs	12,829,355	6,667,669	6,414,921
General and administrative expenses	5,894,008	3,488,864	6,439,323
Stock-based compensation	5,696,173	1,536,271	1,241,404
Depreciation and amortization	1,345,655	1,751,412	1,748,975
Impairment expense	2,172,387	1,308,047
Contingent consideration - Fair Value Adjustments	2,375,658	1,421,652
TOTAL OPERATING EXPENSES	53,451,286	24,879,542	21,236,086
OPERATING LOSS	(53,276,286)	(24,589,276)	(21,089,211)
OTHER INCOME (EXPENSE)
Equity in income (loss) of unconsolidated affiliates	(78,874)	(641,141)	(240,154)
Impairment on investment in unconsolidated affiliates			(1,642,775)
Gain on purchase of Roche Madison			1,576,107
Gain (loss) on sale of fixed assets, net	(58,878)	(76,388)	(1,079,377)
Realized and unrealized gain (loss) in marketable securities			(58,091)
Interest income (expense), net	645,493	(97,910)	35,966
Change in value of derivatives	(6,033,659)	(5,300,389)	386,892
Other income (expense)	82,092	(997,975)
TOTAL OTHER INCOME (EXPENSE)	(5,443,826)	(7,113,803)	(1,021,432)
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(58,720,112)	(31,703,079)	(22,110,643)
Provision for income taxes	(5,300)
LOSS FROM CONTINUING OPERATIONS	(58,725,412)	(31,703,079)	(22,110,643)
NET INCOME (LOSS) FROM DISCONTINUED OPERATIONS		(354)	(80)
NET LOSS	(58,725,412)	(31,703,433)	(22,110,723)
Net (gain) loss attributable to non-controlling interests	95,222	560,144	984,795
NET LOSS ATTRIBUTABLE TO ARROWHEAD	$ (58,630,190)	$ (31,143,289)	$ (21,125,928)
NET LOSS PER SHARE ATTRIBUTABLE TO ARROWHEAD	$ (1.25)	$ (1.30)	$ (1.90)
SHAREHOLDERS - BASIC & DILUTED:
Weighted average shares outstanding - basic and diluted	46,933,030	24,002,224	11,129,766