MARKETABLE SECURITIES - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Cash and cash equivalents	$ 701,334	$ 177,528
Estimated Fair Value	652,407	175,007
Equity securities	1,025	1,716
Marketable Securities, Total	530,062	146,401
Cash, Cash Equivalents, and Short-term Investments, Total	1,231,396	323,929
Cash equivalents
Marketable Securities [Line Items]
Cash and cash equivalents	123,370	30,322
Estimated Fair Value	123,370	30,322
Short-term Investments
Marketable Securities [Line Items]
Estimated Fair Value	529,037	144,685
Cash and money market
Marketable Securities [Line Items]
Cash and cash equivalents	577,684	146,932
Restricted cash
Marketable Securities [Line Items]
Cash and cash equivalents	$ 280	$ 274

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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-Name Accounting Standards Codification
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Amount of investment in marketable security.

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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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