SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Schedule of Changes in Options Outstanding) (Details) $ / shares in Units, $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($) $ / shares shares
Number of Options
Balance \| shares	120,083
Exercised \| shares	(17,283)
Expired \| shares	(715)
Forfeited \| shares	(3,475)
Balance \| shares	98,610
Vested and expected to vest \| shares	98,610
Exercisable \| shares	98,610
Weighted Average Exercise Price
Balance \| $ / shares	$ 14.41
Exercised \| $ / shares	16.20
Expired \| $ / shares	19.95
Forfeited \| $ / shares	24.33
Balance \| $ / shares	13.71
Vested and expected to vest \| $ / shares	13.71
Exercisable \| $ / shares	$ 13.71
Weighted Average Remaining Contractual Term
Balance	2 years 11 months 15 days
Vested and expected to vest	2 years 11 months 15 days
Exercisable	2 years 11 months 15 days
Aggregate Intrinsic Value
Balance \| $	$ 1,694
Vested and expected to vest \| $	1,694
Exercisable \| $	$ 1,694

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest exercisable options that may be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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