Consolidated Statements of Operations (unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
REVENUE	$ 39,583	$ 123,750	$ 127,083	$ 338,250
OPERATING EXPENSES
Research and development	9,423,195	7,490,400	29,782,854	36,877,925
Acquired in-process research and development				10,142,786
Salaries and payroll-related costs	4,113,262	3,570,531	12,281,841	10,262,799
General and administrative expenses	2,275,628	1,829,393	8,045,571	5,612,219
Stock-based compensation	2,750,785	2,486,074	7,547,967	6,706,009
Depreciation and amortization	818,200	741,058	2,416,461	1,480,656
TOTAL OPERATING EXPENSES	19,381,070	16,117,456	60,074,694	71,082,394
OPERATING LOSS	(19,341,487)	(15,993,706)	(59,947,611)	(70,744,144)
OTHER INCOME (EXPENSE)
Gain (loss) on sale of fixed assets, net				19,195
Interest income (expense), net	34,103	162,366	213,543	597,896
Change in value of derivatives	(113,359)	(104,713)	233,052	2,446,403
Other income (expense)				482,904
TOTAL OTHER INCOME (EXPENSE)	(79,256)	57,653	446,595	3,546,398
LOSS BEFORE INCOME TAXES	(19,420,743)	(15,936,053)	(59,501,016)	(67,197,746)
NET LOSS	(19,420,743)	(15,936,053)	(59,501,016)	(67,197,746)
NET LOSS ATTRIBUTABLE TO ARROWHEAD	$ (19,420,743)	$ (15,936,053)	$ (59,501,016)	$ (67,197,746)
NET LOSS PER SHARE ATTRIBUTABLE TO ARROWHEAD SHAREHOLDERS - BASIC AND DILUTED:	$ (0.32)	$ (0.27)	$ (1.00)	$ (1.19)
Weighted average shares outstanding - basic and diluted	59,966,955	59,492,867	59,764,129	56,631,297
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX
Foreign Currency Translation Adjustments	$ (90,625)	$ (1,982)	$ 105,713	$ (65,947)
COMPREHENSIVE LOSS ATTRIBUTABLE TO ARROWHEAD	$ (19,511,368)	$ (15,938,035)	$ (59,395,303)	$ (67,263,693)