FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value Assets
Marketable securities	$ 269,650	$ 293,269
Capped call transactions	64,480	83,597
Cash equivalents
Fair Value Assets
Cash equivalents	26,657	56,339
Venture investments
Fair Value Assets
Venture investments	9,756	8,345
Level 1
Fair Value Assets
Marketable securities	0	0
Capped call transactions	0	0
Level 1 \| Cash equivalents
Fair Value Assets
Cash equivalents	26,657	42,339
Level 1 \| Venture investments
Fair Value Assets
Venture investments	0	0
Level 2
Fair Value Assets
Marketable securities	269,650	293,269
Capped call transactions	64,480	83,597
Level 2 \| Cash equivalents
Fair Value Assets
Cash equivalents	0	14,000
Level 2 \| Venture investments
Fair Value Assets
Venture investments	0	0
Level 3
Fair Value Assets
Marketable securities	0	0
Capped call transactions	0	0
Level 3 \| Cash equivalents
Fair Value Assets
Cash equivalents	0	0
Level 3 \| Venture investments
Fair Value Assets
Venture investments	$ 9,756	$ 8,345

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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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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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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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