Initial and Follow On Public Offerings (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended				12 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended	12 Months Ended		3 Months Ended			0 Months Ended				0 Months Ended	12 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Jun. 12, 2013	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]	Jun. 12, 2013 Common Stock [Member] Convertible Debentures [Member]	Dec. 31, 2012 Common Stock [Member] Convertible Debentures [Member]	Jun. 12, 2013 IPO [Member]	Sep. 30, 2013 IPO [Member]	Jun. 11, 2013 IPO [Member]	Sep. 30, 2013 IPO [Member] Convertible Debentures [Member] Interest Expense [Member]	Sep. 30, 2013 IPO [Member] Convertible Debentures [Member]	Jun. 12, 2013 IPO [Member] Redeemable Preferred Stock, Series A-1 [Member]	Jun. 12, 2013 IPO [Member] Common Stock [Member]	Jun. 12, 2013 IPO [Member] Common Stock [Member] Convertible Debentures [Member]	Jun. 12, 2013 IPO [Member] Convertible A-1 and A-2 Preferred Stock [Member]	Jun. 12, 2013 IPO [Member] Preferred Class A [Member] Submittal Exchange [Member]	Sep. 20, 2013 Follow on Public Offering [Member]	Sep. 30, 2013 Follow on Public Offering [Member]	Sep. 20, 2013 Follow on Public Offering [Member] Common Stock [Member]
Class of Stock [Line Items]
Shares converted into stock															0.3521126761				0.50
Common stock, shares outstanding	24,629,000	8,570,000								22,839,000		9,935,000
Offering price per share				$ 15.00																$ 38.00
Recognition of unamortized debt discount upon conversion					$ 2,250	$ 0	$ 4,615						$ 863
Aggregate offering price, net of issuance costs	138,613	0	0													80,213				61,221		61,221
Underwriting discounts and commissions																6,037						2,885
Other income related to conversion option														82
Aggregate offering proceeds											77,709					77,709					59,779	59,779
Other offering costs																$ 2,504						$ 1,442
Shares of stock issued										750,000						5,750,000						1,687,000
Shares converted into stock																		5,336,000	963,000
Preferred Stock Dividends, Shares																		412,000
Shares isued in debt converstion								443,000	826,000								443,000