BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - CONCENTRATION RISK (Details)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Net revenue | Customer concentration risk | Five largest customers
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	71.50%	70.10%	70.70%
Net revenue | Customer concentration risk | One Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	31.90%	31.30%	30.20%
Net revenue | Customer concentration risk | Second Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	20.00%	18.10%	17.60%
Net revenue | Customer concentration risk | Third Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate		10.50%
Gross accounts receivable | Credit concentration risk | Five largest customers
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	58.10%	66.60%
Gross accounts receivable | Credit concentration risk | Additional customer two
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	29.40%	19.40%
Gross accounts receivable | Credit concentration risk | Additional customer three
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	40.10%	15.70%
Gross accounts receivable | Credit concentration risk | Customers individually accounting for more than 10%
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	48.80%	55.80%