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Amount per share of equity securities issued under the employee stock purchase plan.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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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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Purchase price of common stock expressed as a percentage of its fair value.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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SHAREHOLDERS' EQUITY - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2004	Dec. 31, 2019	Dec. 31, 2018	Aug. 14, 2018	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Par value (in dollars per share)		$ 0.0001	$ 0.0001	$ 0.0001
Options exercised during period (in shares)			278,000
Net proceeds from options exercised during the period			$ 1.5
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance (in shares)		3,000,000
Number of shares available for future issuance (in shares)		133,759
Shares sold (in shares)		168,790	106,500
Weighted average purchase price of shares sold (in dollars per share)		$ 1.34	$ 4.95
Proceeds from shares sold		$ 0.2	$ 0.5
ESPP \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price expressed as percentage of fair market value of common stock	85.00%
Additional Paid-In Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock upon exercise of options					$ 264.5