STOCK-BASED COMPENSATION - Assumptions (Details) - $ / shares	3 Months Ended	6 Months Ended
Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award
Grant date fair value of stock options granted	$ 0.41		$ 0.56
Expected volatility	96.70%
Expected term in years	9 years 10 months 24 days	6 years 6 months		6 years 6 months
Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Expected volatility		97.00%	95.50%	97.00%
Expected term in years			6 years
Risk-free interest rate	2.29%	1.14%	1.80%	1.14%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Expected volatility		98.60%	96.80%	98.60%
Expected term in years			9 years 10 months 24 days
Risk-free interest rate		1.28%	2.29%	1.28%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

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.

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No definition available.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of share-based compensation awards, 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 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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