MARKETABLE SECURITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 20,291	$ 93,301
Unrealized Gains	174	36
Unrealized Losses	0	(336)
Fair Value	$ 20,465	93,001
Weighted-average remaining maturity	1 year 6 months
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 10,680	44,802
Unrealized Gains	69	13
Unrealized Losses	0	(110)
Fair Value	10,749	44,705
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,611	48,499
Unrealized Gains	105	23
Unrealized Losses	0	(226)
Fair Value	$ 9,716	$ 48,296

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
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Period between issuance and maturity of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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