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STOCK-BASED COMPENSATION - Summary of Stock options exercised, restricted stock vested, shares withheld and shares issued (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Number of Shares
Stock compensation expense	$ 552,000	$ 567,000	$ 1,100,000	$ 1,100,000
Unrecognized compensation expense	$ 4,600,000		$ 4,600,000
Weighted average period			2 years 4 months 24 days
Stock options
Number of Shares
Stock Options, Exercised/Vested			2,524	14,844
Stock Options, Shares withheld				(2,038)
Stock Options, Shares Issued			2,524	12,806
Non-performance based restricted stock
Number of Shares
Restricted Stock, Exercised/Vested			14,550	3,100
Restricted Stock, Shares withheld			(1,697)	(658)
Restricted Stock, Shares Issued			$ 12,853	$ 2,442