Convertible Debentures (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended						0 Months Ended	1 Months Ended	12 Months Ended				12 Months Ended			3 Months Ended	0 Months Ended	1 Months Ended	0 Months Ended		12 Months Ended			0 Months Ended	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Jun. 12, 2013	Sep. 30, 2013 Convertible Debentures 2009 [Member]	Sep. 30, 2013 Convertible Debentures 2010 [Member]	Jun. 12, 2013 Convertible Debentures [Member]	Dec. 31, 2012 Convertible Debentures [Member]	Sep. 30, 2013 Convertible Debentures [Member]	Sep. 30, 2012 Convertible Debentures [Member]	Sep. 30, 2011 Convertible Debentures [Member]	Sep. 30, 2010 Convertible Debentures [Member]	Sep. 30, 2013 Convertible Debentures [Member] Interest Expense [Member]	Sep. 30, 2012 Convertible Debentures [Member] Interest Expense [Member]	Sep. 30, 2011 Convertible Debentures [Member] Interest Expense [Member]	Sep. 30, 2013 Convertible Debentures [Member] IPO [Member] Interest Expense [Member]	Jun. 12, 2013 Convertible Debentures [Member] Common Stock [Member]	Dec. 31, 2012 Convertible Debentures [Member] Common Stock [Member]	Jun. 12, 2013 Convertible Debentures [Member] Common Stock [Member] IPO [Member]	May 01, 2011 Convertible Debentures [Member] Convertible Debentures 2009 [Member]	Sep. 30, 2013 Convertible Debentures [Member] Convertible Debentures 2009 [Member]	Sep. 30, 2012 Convertible Debentures [Member] Convertible Debentures 2009 [Member]	Sep. 30, 2011 Convertible Debentures [Member] Convertible Debentures 2009 [Member]	Aug. 01, 2011 Convertible Debentures [Member] Convertible Debentures 2010 [Member]	Sep. 30, 2013 Convertible Debentures [Member] Convertible Debentures 2010 [Member]	Sep. 30, 2013 Convertible Debentures [Member] Convertible Debentures 2011 [Member]
Debt Instrument [Line Items]
Proceeds from convertible debentures, before allocations									$ 0	$ 14,664	$ 5,465
Fair value of embedded derivatives										467	153
Stated interest rate (as a percent)									8.00%
Period for consecutive positive cashflow																					3 months				6 months
Percentage of number of shares of common stock converted which equals to additional warrants issued					50.00%	50.00%
Maturity period																					10 years				5 years	5 years
Issuance of common shares								12,392	(19,035)	0	(23,457)
Conversion price (USD per share)							$ 15.00													$ 16.26				$ 13.25
Shares issued in debt conversion																	443	826	443	740				862
Issuance of common stock upon conversion of debentures	16,784	0	17,730				5,865
PIK interest							778						707	1,171	1,384
Unamortized debt discount								1,387	0	2,440	529	5,625
Offering price per share				$ 15.00
Interest expense recognized	4,717	2,205	7,264						3,147	1,526	6,588
Recognition of unamortized debt discount upon conversion													$ 2,250	$ 0	$ 4,615	$ 863					$ 0	$ 0	$ 1,112