Acquisition of Controlling Interest in the Company - Narrative (Details) - USD ($)		1 Months Ended	3 Months Ended						12 Months Ended
	Sep. 12, 2016	Jan. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Warrant liability reclassification ( See Note 19)									$ 16,791,000	$ 0	$ 0
Change in fair value of warrants			$ 5,597,000	$ 5,597,000	$ (3,235,000)	$ 642,000	$ (1,773,000)	$ (4,092,000)	$ (11,194,000)	$ 8,458,000	0
FBIO Acquisitions Inc. | Common Stock
Business Acquisition [Line Items]
Warrant contract term									5 years
Warrant price (in dollars per share)									$ 3.25
FBIO Acquisitions Inc. | National Holdings Corp
Business Acquisition [Line Items]
Acquisition costs											4,300,000
Stock ownership percentage required to become a privately held company	80.00%
FBIO Acquisitions Inc. | National Holdings Corp | Common Stock
Business Acquisition [Line Items]
Acquisition share price (in dollars per share)	$ 3.25
Number of shares tendered for acquisition (in shares)	7,037,482
Equity interest after business acquisition	56.60%
Professional Fees | FBIO Acquisitions Inc. | National Holdings Corp
Business Acquisition [Line Items]
Acquisition costs											3,000,000
Commission, Compensation, and Fees | FBIO Acquisitions Inc. | National Holdings Corp
Business Acquisition [Line Items]
Acquisition costs											1,100,000
Other Administrative Expense | FBIO Acquisitions Inc. | National Holdings Corp
Business Acquisition [Line Items]
Acquisition costs											$ 200,000
Warrants | FBIO Acquisitions Inc. | Common Stock
Business Acquisition [Line Items]
Warrants issued (in shares)		12,437,916