STOCK-BASED COMPENSATION - Stock option activity (Details) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Options [Member]
Option Shares
Outstanding at the beginning of the period (in shares)	756	757
Granted (in shares)	97	42
Exercised (in shares)	(5)	(8)
Forfeited (in shares)	(74)	(44)
Outstanding at the end of the period (in shares)	774	747
Inducement Grants [Member]
Option Shares
Outstanding at the beginning of the period (in shares)	180
Granted (in shares)	61	180
Outstanding at the end of the period (in shares)	241	180