STOCKHOLDERS' EQUITY - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions			9 Months Ended
	May 07, 2019	Sep. 19, 2017	Mar. 31, 2019	Mar. 31, 2018	May 09, 2018
Follow on offering
Class of Stock [Line Items]
Issuance of common stock (in shares)		24.1
Offering price (in dollars per share)		$ 10.75
Net proceeds from the issuance of common stock		$ 243,000
Offering costs for issuance of common stock		$ 15,700	$ 0	$ 15,732
Net proceeds from the issuance of common stock			0	258,750
Underwriters option
Class of Stock [Line Items]
Issuance of common stock (in shares)		3.1
Market offering
Class of Stock [Line Items]
Offering costs for issuance of common stock			2,517	876
Net proceeds from the issuance of common stock			125,043	$ 41,216
Common Stock | Cantor
Class of Stock [Line Items]
Average price per share (in dollars per share)				$ 16.14
Common Stock | Market offering | Cantor
Class of Stock [Line Items]
Dollar amount of stock that may be sold under the agreement					$ 125,000
Commission under sales agreement, percent					3.00%
Net proceeds from the issuance of common stock			$ 122,500	$ 40,300
Average price per share (in dollars per share)			$ 17.24
Common Stock | Market offering | Jefferies | Subsequent Event
Class of Stock [Line Items]
Dollar amount of stock that may be sold under the agreement	$ 150,000
Commission under sales agreement, percent	3.00%
Net proceeds from the issuance of common stock	$ 0