MARKETABLE SECURITITES Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Interest receivable	$ 1,065	$ 1,279
Amortized Cost	192,359	231,815
Gross Unrealized Gains	2,197	589
Gross Unrealized Losses	0	(6)
Estimated Fair Market Value	194,556	232,398
Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	28,026	15,934
Gross Unrealized Gains	77	18
Gross Unrealized Losses	0	0
Estimated Fair Market Value	28,103	15,952
Investments due in 4-12 months:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	133,251	71,223
Gross Unrealized Gains	1,597	269
Gross Unrealized Losses	0	0
Estimated Fair Market Value	134,848	71,492
Investments due in 12 months or greater:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	31,082	144,658
Gross Unrealized Gains	523	302
Gross Unrealized Losses	0	(6)
Estimated Fair Market Value	31,605	144,954
Commercial paper \| Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,996
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Market Value	2,996
Corporate securities \| Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	25,030	15,934
Gross Unrealized Gains	77	18
Gross Unrealized Losses	0	0
Estimated Fair Market Value	25,107	15,952
Corporate securities \| Investments due in 4-12 months:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	133,251	71,223
Gross Unrealized Gains	1,597	269
Gross Unrealized Losses	0	0
Estimated Fair Market Value	134,848	71,492
Corporate securities \| Investments due in 12 months or greater:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	31,082	144,658
Gross Unrealized Gains	523	302
Gross Unrealized Losses	0	(6)
Estimated Fair Market Value	$ 31,605	$ 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

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-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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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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