Stockholders' equity (Details 6) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Shares
Outstanding, beginning balance	9,559,113
Granted	138,333	820,000	2,589,667
Outstanding, ending balance	9,544,657	9,559,113
Stock Options And Warrants [Member]
Shares
Outstanding, beginning balance	5,544,671	5,095,103
Granted	138,333	820,001
Cancelled or expired	235,012	370,433
Exercised
Outstanding, ending balance	4,225,664	5,544,671
Weighted Average Exercise Price
Outstanding, beginning balance	$ 6.84	$ 6.85
Granted	$ 1.95	$ 6.86
Cancelled or expired	$ 7.60	$ 6.91
Exercised
Outstanding, ending balance	$ 6.75	$ 6.84
Exercisable	$ 6.75	$ 6.90
Weighted Average Remaining Contractual Term
Outstanding, weighted average remaining contractual term	37 months 29 days	40 months 18 days
Exercisable, weighted average remaining contractual term	37 months	39 months 12 days
Outstanding, aggregate intrinsic value
Exercisable, aggregate intrinsic vaue
Weighted average grant date fair value of options and warrants granted	$ 1.95	$ 6.86
Aggregate intrinsic value of options and warrants exercised
Weighted average fair value of options and warrants vested	$ 4.50	$ 6.90