QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2020		Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020		Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2020		Dec. 31, 2019
Selected quarterly financial data [Abstract]
Net sales	$ 21,803		$ 15,990		$ 9,146		$ 17,145		$ 20,469		$ 16,311		$ 17,197		$ 20,941
Gross profit	11,660		9,289		5,243		9,866		11,495		8,849		9,370		12,245		$ 36,058		$ 41,959
Net income (loss)	$ (406)		$ (982)		$ (1,775)		$ (1,738)		$ (829)		$ (1,719)		$ (875)		$ 1,520		$ (4,901)	[1]	$ (1,903)	[1]
Net income (loss) per common share [Abstract]
Basic (in dollars per share)	$ (0.04)		$ (0.11)		$ (0.20)		$ (0.19)		$ (0.09)		$ (0.19)		$ (0.10)		$ 0.17		$ (0.54)		$ (0.21)
Diluted (in dollars per share)	$ (0.04)	[2]	$ (0.11)	[2]	$ (0.20)	[2]	$ (0.19)	[2]	$ (0.09)	[3]	$ (0.19)	[3]	$ (0.10)	[3]	$ 0.17	[3]	$ (0.54)		$ (0.21)
Weighted average number of common shares outstanding [Abstract]
Basic (in shares)	9,134,621		9,042,991		9,042,991		9,029,212		9,020,187		8,932,246		8,933,648		9,009,752		9,062,598	[1]	8,973,246	[1]
Diluted (in shares)	9,134,621		9,042,991		9,042,991		9,029,212		9,020,187		8,932,246		8,933,648		9,011,107		9,062,598	[1]	8,973,246	[1]
Shares excluded from diluted EPS (in shares)	3,300		1,875		2,290		492		8,387		2,704		2,290

[1] For the years ended December 31, 2020 and 2019, there were 6,401 and 9,203 shares, respectively, excluded from the diluted EPS calculation because the impact of their assumed vesting would be anti-dilutive due to a net loss in that period.

[2] For the three months ended March 31, 2020, June 30, 2020, September 30, 2020, and December 31, 2020, there were 492, 2,290, 1,875 and 3,300 shares, respectively, excluded from the diluted EPS calculation because the impact of their assumed exercise would be anti-dilutive due to a net loss in those periods.

[3] For the three months ended June 30, 2019, September 30, 2019 and December 31, 2019, there were 2,290, 2,704 and 8,387 shares, respectively, excluded from the diluted EPS calculation because the impact of their assumed exercise would be anti-dilutive due to a net loss in those periods.