BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - CONCENTRATION RISK (Details) - number_of_customer	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Concentration of Credit Risk and Accounts Receivable
Number of customers	5
Net revenue | Customer concentration risk | Five largest customers
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	70.10%	70.70%	65.50%
Net revenue | Customer concentration risk | One Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	31.30%	30.20%	26.30%
Net revenue | Customer concentration risk | Second Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	18.10%	17.60%	14.20%
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	66.60%	65.40%
Gross accounts receivable | Credit concentration risk | Additional customer two
Concentration of Credit Risk and Accounts Receivable
Number of customers	2
Concentration risk rate	40.10%	15.70%
Gross accounts receivable | Credit concentration risk | Additional customer three
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	37.70%	15.50%
Gross accounts receivable | Credit concentration risk | Customers individually accounting for more than 10%
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	55.80%	53.20%