BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - CONCENTRATION RISK (Details) - number_of_customer	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
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	70.70%	65.50%	58.90%
Net revenue | Customer concentration risk | One Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	30.20%	26.30%	20.70%
Net revenue | Customer concentration risk | Second Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	17.60%	14.20%	15.50%
Net revenue | Customer concentration risk | Third Customer
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	10.90%
Gross accounts receivable | Credit concentration risk | Five largest customers
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	65.40%	69.90%
Gross accounts receivable | Credit concentration risk | Additional customer two
Concentration of Credit Risk and Accounts Receivable
Number of customers	2
Concentration risk rate	37.70%	15.50%
Gross accounts receivable | Credit concentration risk | Additional customer three
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	40.20%	17.40%
Gross accounts receivable | Credit concentration risk | Customers individually accounting for more than 10%
Concentration of Credit Risk and Accounts Receivable
Concentration risk rate	53.20%	57.60%