EARNINGS PER SHARE (''EPS'') - Reconciliation of the Numerator and Denominator Used in Computing Basic and Diluted Per Share Computations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss attributable to common stockholders	$ (3,216)	$ (9,678)	$ (15,632)	$ (24,606)
Redeemable preferred stock dividends declared on dilutive shares	0	0	0	(1)
Diluted net loss attributable to common stockholders	$ (3,216)	$ (9,678)	$ (15,632)	$ (24,607)
Denominator:
Basic weighted average shares outstanding (in shares)	23,349,000	14,805,000	17,784,000	14,729,000
Diluted weighted average shares and common stock equivalents outstanding (in shares)	23,350,000	14,805,000	17,784,000	14,729,000
Net loss attributable to common stockholders per share:
Basic (in usd per share)	$ (0.14)	$ (0.65)	$ (0.88)	$ (1.67)
Diluted (in usd per share)	$ (0.14)	$ (0.65)	$ (0.88)	$ (1.67)
Series A Preferred Stock
Denominator:
Effect of dilutive securities—contingently issuable shares (in shares)	1,000	0	0	108