STOCK-BASED COMPENSATION - COMPENSATION EXPENSE (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Stock-based compensation expense
Stock-based compensation expense before income taxes	$ 257,881	$ 247,700	$ 116,349
Income tax benefit	(48,687)	(48,383)	(3,561)
Stock-based compensation expense, net of income tax benefit	209,194	199,317	112,788
Capitalized stock-based compensation expense	24,451	75,725	90,914
Cost of goods sold
Stock-based compensation expense
Stock-based compensation expense before income taxes	154,031	149,075	24,610
Selling and marketing
Stock-based compensation expense
Stock-based compensation expense before income taxes	18,680	23,685	13,258
General and administrative
Stock-based compensation expense
Stock-based compensation expense before income taxes	53,607	51,903	58,037
Research and development
Stock-based compensation expense
Stock-based compensation expense before income taxes	31,563	23,037	18,020
Business reorganization
Stock-based compensation expense
Stock-based compensation expense before income taxes	$ 0	$ 0	$ 2,424