STOCKHOLDERS' (DEFICIT) EQUITY - Equity Financing (Details) - USD ($)		1 Months Ended				3 Months Ended	12 Months Ended
	Oct. 30, 2020	Nov. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2020
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Stock price per share (in dollars per share)				$ 1.80	$ 1.13
Commission fixed rate		3.00%
Legal, accounting and printing costs							$ 200,000	$ 200,000
Proceeds from sale of stock			$ 27,800,000	$ 41,900,000	$ 9,000,000.0
Sale of stock, shares issued (in shares)			20,400,000	25,600,000	8,000,000.0
Issuance of common stock, issuance cost						$ 700,000	1,200,000
Number of warrants (in shares)					8,000,000.0				20,400,000
Stock and warrants price per share (in dollars per share)									$ 1.47
Exercise price per warrant (in dollars per share)					$ 1.20				$ 1.47
Warrant price per unit (in dollars per share)					$ 0.125
Warrants exercise period					5 years				1 year
ATM Facility
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Aggregate sales price		$ 35,000,000.0
Proceeds from sale of stock						$ 21,800,000	$ 38,000,000.0
Sale of stock, shares issued (in shares)						16,600,000	33,400,000
Weighted-average stock price per share (in dollars per share)						$ 1.36	$ 1.17
Additional shares issued (in shares)	50,000,000