STOCKHOLDERS' (DEFICIT) EQUITY - Common Stock (Details)	12 Months Ended
	Dec. 31, 2020 vote $ / shares shares	Dec. 31, 2019 $ / shares shares	Dec. 31, 2018 shares	Dec. 31, 2017 shares
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	200,000,000.0	200,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	140,449,647	106,801,409
Common stock, shares outstanding (in shares)	140,400,000	106,800,000
Common Stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)	140,449,647	106,801,409	77,456,180	34,702,565
Number of votes | vote	1