Consolidated Statements of Operations (unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
REVENUE	$ 123,750	$ 43,750	$ 338,250	$ 131,250
OPERATING EXPENSES
Research and development	7,490,400	6,392,200	36,877,925	14,719,739
Acquired in-process research and development			10,142,786
Salaries and payroll-related costs	3,570,531	2,454,449	10,262,799	7,634,142
General and administrative expenses	1,829,393	1,582,465	5,612,219	3,865,845
Stock-based compensation	2,486,074	2,038,682	6,706,009	3,758,264
Depreciation and amortization	741,058	276,054	1,480,656	1,075,238
TOTAL OPERATING EXPENSES	16,117,456	12,743,850	71,082,394	31,053,228
OPERATING LOSS	(15,993,706)	(12,700,100)	(70,744,144)	(30,921,978)
OTHER INCOME (EXPENSE)
Equity in income (loss) of unconsolidated affiliates		78,702		(69,350)
Gain (loss) on sale of fixed assets, net			19,195	(58,878)
Interest income (expense), net	162,366	226,424	597,896	386,392
Change in value of derivatives	(104,713)	758,469	2,446,403	(5,712,335)
Other income (expense)		10,054	482,904	81,269
TOTAL OTHER INCOME (EXPENSE)	57,653	1,073,649	3,546,398	(5,372,902)
LOSS BEFORE INCOME TAXES	(15,936,053)	(11,626,451)	(67,197,746)	(36,294,880)
NET LOSS	(15,936,053)	(11,626,451)	(67,197,746)	(36,294,880)
Net loss attributable to noncontrolling interests		(2,468)		95,132
NET LOSS ATTRIBUTABLE TO ARROWHEAD	$ (15,936,053)	$ (11,628,919)	$ (67,197,746)	$ (36,199,748)
NET LOSS PER SHARE ATTRIBUTABLE TO ARROWHEAD SHAREHOLDERS - BASIC AND DILUTED:	$ (0.27)	$ (0.22)	$ (1.19)	$ (0.81)
Weighted average shares outstanding - basic and diluted	59,492,867	51,931,989	56,631,297	44,565,008
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX
Foreign Currency Translation Adjustments	$ (1,982)		$ (65,947)
COMPREHENSIVE LOSS ATTRIBUTABLE TO ARROWHEAD	$ (15,938,035)	$ (11,628,919)	$ (67,263,693)	$ (36,199,748)