Fair Value Measurements - Assumptions Used in Valuing Derivative Liabilities (Detail)	6 Months Ended	12 Months Ended
Mar. 31, 2015	Sep. 30, 2014
2010 Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Risk-free interest rate	0.26%	0.13%
Expected life	8 months 12 days	1 year 2 months 12 days
Dividend yield	0.00%	0.00%
Volatility	75.00%	69.00%
2012 Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Risk-free interest rate	0.89%	1.07%
Expected life	2 years 8 months 12 days	3 years 2 months 12 days
Dividend yield	0.00%	0.00%
Volatility	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	0.89%	1.07%
Expected life	2 years 9 months 18 days	3 years 3 months 18 days
Dividend yield	0.00%	0.00%
Volatility	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	1.00%	1.07%
Expected life	3 years	3 years 3 months 18 days
Volatility	75.00%	100.00%

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Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

+ 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 (e)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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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.

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- Definition

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

+ References

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- Definition

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

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