Subsequent Events (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
Jun. 30, 2012 Units
Subsequent Events [Abstract]
Date of selling units in registered offering	August 13, 2012
Units sold in registered offering to institutional and individual investors	2,300,000
Selling price per unit sold in registered offering	2.76
Unit sold, description	Each unit consisted on one share of Arrowhead Common Stock and a warrant
Number of shares that can be purchased by a warrant	0.75
Common stock exercisable price	$ 3.25
Gross proceeds from registered offerings	$ 6.2
Net proceeds from registered offerings after deducting commissions and fees	$ 5.8

2,300,000

Each unit consisted on one share of Arrowhead Common Stock and a warrant

$ 3.25

$ 5.8