FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Maturities of cash equivalents and available-for-sale investments (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Amortized Cost
Mature in less than one year	$ 273,656
Mature in one to five years	19,983
Total	293,639
Fair Value
Mature in less than one year	273,738
Mature in one to five years	19,954
Total	$ 293,692

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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