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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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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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Number of options outstanding, including both vested and non-vested options.

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Percentage of vesting of award under share-based payment arrangement.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average grant-date fair value of non-vested options outstanding.

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Number of options vested.

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SHARE-BASED COMPENSATION - Additional Information (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jun. 30, 2019	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)			6,236,000	3,942,000	2,696,000	2,024,000
Share-based compensation expense			$ 1,237,000	$ 1,283,000	$ 1,381,000
Unrecognized compensation expense			$ 3,200,000
Option granted, weighted average grant date fair value (in dollars per share)			$ 0.69	$ 1.14	$ 1.18
Total intrinsic value of options exercised				$ 500,000	$ 300,000
Stock options granted (in shares)			3,986,000	3,546,000	1,303,000
Inducement Equity Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)			2,100,000
Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Share-based compensation expense				$ 200,000	$ 300,000
Unrecognized compensation expense			$ 0
Option granted, weighted average grant date fair value (in dollars per share)		$ 1.12
Stock options granted (in shares)		900,000.0
Stock options exercise price (in dollars per share)		$ 1.59
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense			$ 1,200,000	$ 1,100,000	900,000
Weighted average period unvested stock to be recognized			2 years 10 months 23 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense					$ 200,000
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)			4,000,000
Number of shares reserved for issuance (in shares)	7,900,000
Stock incentive plan, shares remained available for future issuance (in shares)			8,800,000
2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Expected term			10 years
2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested stock options outstanding (in shares)			100,000
Vesting on the First Anniversary of Date of Grant \| 2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of original number of shares subject to the option vesting			25.00%
Vesting at End of Each Successive Three-Month Period Thereafter \| 2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of original number of shares subject to the option vesting			6.25%