GOODWILL AND INTANGIBLE ASSETS - Schedule of Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	$ 26,477	$ 28,434	$ 59,138	$ 56,639
Product revenue
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	0	2	0	4
Cost of product revenue
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	8,491	10,129	17,682	19,943
Operating expense
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	$ 17,986	$ 18,303	$ 41,456	$ 36,692