STOCKHOLDERS' EQUITY: - Effect of stock-based compensation expense on income, by financial statement line item (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Share-based compensation
Total non-cash stock-based compensation	$ 111,707	$ 89,447	$ 102,722
Cost of revenue
Share-based compensation
Total non-cash stock-based compensation	5,300	3,769	4,708
Research and development
Share-based compensation
Total non-cash stock-based compensation	38,960	23,260	28,225
Sales and marketing
Share-based compensation
Total non-cash stock-based compensation	40,401	38,026	43,971
General and administrative
Share-based compensation
Total non-cash stock-based compensation	$ 27,046	$ 24,392	$ 25,818