Fair Value Measurements - Assumptions Used in Valuing Derivative Liabilities (Detail)	12 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
2012 Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Risk-free interest rate	0.68%	0.60%	1.07%
Expected life	1 year 2 months 12 days	2 years 2 months 12 days	3 years 2 months 12 days
Volatility	89.00%	75.00%	69.00%
2013 Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Risk-free interest rate	0.68%	0.60%	1.07%
Expected life	1 year 3 months 18 days	2 years 3 months 18 days	3 years 3 months 18 days
Volatility	89.00%	75.00%	69.00%
Exchange rights
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Risk-free interest rate	0.68%	1.00%	1.07%
Expected life	1 year 6 months	2 years 6 months	3 years 3 months 18 days
Volatility	89.00%	75.00%	100.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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- Definition

Risk-free interest rate assumption used in valuing an instrument.

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