INCOME TAXES - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Income Tax Contingency [Line Items]
Deferred tax asset adjustment due to change in enacted tax rate			$ 0	$ 22,630,000	$ 0
Provision (benefit) for income taxes			569,000	66,294,000	(126,000)
Undistributed earnings (losses) of foreign subsidiaries	$ (19,700,000)		200,000	(19,700,000)	$ (8,400,000)
Deferred tax assets, valuation allowance	$ 62,174,000		$ 65,948,000	62,174,000
Federal tax rate	21.00%	34.00%	21.00%		34.00%
Unrecognized tax benefits	$ 3,980,000		$ 5,033,000	3,980,000	$ 3,331,000	$ 2,881,000
Accrued penalties and interest	$ 0		0	$ 0	$ 0
Internal Revenue Service (IRS)
Income Tax Contingency [Line Items]
Research tax credit carryforwards			10,100,000
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Operating loss carryforwards			80,000,000
Research tax credit carryforwards			11,500,000
Tax Year 2019 | Internal Revenue Service (IRS)
Income Tax Contingency [Line Items]
Operating loss carryforwards			88,600,000
Tax Years Prior To 2019 | Internal Revenue Service (IRS)
Income Tax Contingency [Line Items]
Operating loss carryforwards			$ 156,400,000