STOCK-BASED COMPENSATION - Summary of Stock Options (Details)	9 Months Ended
	Sep. 30, 2020 $ / shares shares
Number of options
Outstanding, beginning of period (in shares) | shares	3,966,858
Granted (in shares) | shares	1,376,900
Exercised (in shares) | shares	(81,131)
Canceled and forfeited (in shares) | shares	(234,600)
Outstanding, end of period (in shares) | shares	5,028,027
Weighted average exercise price
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 4.67
Granted (in dollars per share) | $ / shares	7.94
Exercised (in dollars per share) | $ / shares	3.03
Canceled and forfeited (in dollars per shares) | $ / shares	7.57
Outstanding, end of period (in dollars per share) | $ / shares	$ 5.45