Related parties (Details) (USD $)	12 Months Ended			1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	May 31, 2011 Luxco	Mar. 31, 2011 Luxco
Related Party Transaction [Line Items]
Shares sold pursuant to an underwritten follow-on public offering				9,747,480	4,500,000
Sale of stock, costs incurred				$ 200,000	$ 300,000
One-time non-cash compensation charge (payment by shareholder - Note 24)	$ 0	$ 0	$ 6,625,000