STOCK-BASED COMPENSATION - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Options
Outstanding, beginning balance (in shares)	47,735
Granted (in shares)	2,330,739
Outstanding, ending balance (in shares)	2,378,474	47,735
Options vested or expected to vest (in shares)	2,378,474
Options exercisable (in shares)	111,633
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 0.66
Granted (in dollars per share)	8.18
Outstanding, ending balance (in dollars per share)	8.03	$ 0.66
Options vested or expected to vest (in dollars per share)	8.03
Options exercisable (in dollars per share)	$ 4.98
Weighted Average Remaining Life and Intrinsic Value
Options outstanding, remaining life	9 years 8 months 12 days	9 years 6 months
Options vested or expected to vest, remaining life	9 years 8 months 12 days
Options exercisable, remaining life	9 years 2 months 12 days
Options outstanding, intrinsic value	$ 6,722	$ 121
Options vested or expected to vest, intrinsic value	6,722
Options exercisable, intrinsic value	$ 656