CASH, CASH EQUIVALENTS, RESTRICTED CASH AND MARKETABLE SECURITIES - Summary of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Cash and cash equivalents	$ 403,306	$ 338,489	$ 353,721	$ 409,632
Restricted cash	748	1,748	1,189	188
Total cash, cash equivalents and restricted cash	$ 404,054	$ 340,237	$ 354,910	$ 409,820