MARKETABLE SECURITITES Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Interest receivable	$ 1,395	$ 1,279
Amortized Cost	210,362	231,815
Gross Unrealized Gains	1,564	589
Gross Unrealized Losses	0	(6)
Estimated Fair Market Value	211,926	232,398
Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	64,370	15,934
Gross Unrealized Gains	52	18
Gross Unrealized Losses	0	0
Estimated Fair Market Value	64,422	15,952
Investments due in 4-12 months:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	136,410	71,223
Gross Unrealized Gains	1,366	269
Gross Unrealized Losses	0	0
Estimated Fair Market Value	137,776	71,492
Investments due in 12 months or greater:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,582	144,658
Gross Unrealized Gains	146	302
Gross Unrealized Losses	0	(6)
Estimated Fair Market Value	9,728	144,954
Commercial paper \| Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	46,251
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Market Value	46,251
Corporate securities \| Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,119	15,934
Gross Unrealized Gains	52	18
Gross Unrealized Losses	0	0
Estimated Fair Market Value	18,171	15,952
Corporate securities \| Investments due in 4-12 months:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	136,410	71,223
Gross Unrealized Gains	1,366	269
Gross Unrealized Losses	0	0
Estimated Fair Market Value	137,776	71,492
Corporate securities \| Investments due in 12 months or greater:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,582	144,658
Gross Unrealized Gains	146	302
Gross Unrealized Losses	0	(6)
Estimated Fair Market Value	$ 9,728	$ 144,954

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

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+ References

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- Definition

Carrying amount as of the balance sheet date of current interest earned but not received. Also called accrued interest or accrued interest receivable. For classified balance sheets, represents the current amount receivable, that is amounts expected to be collected within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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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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