Supplementary Financial Information to Item 8. (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021		Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 2,405	$ 2,749	$ 2,074	$ 2,637	$ 3,746	$ 5,964	$ 3,335	$ 3,783	$ 9,865		$ 16,828
Gross profit	189	563	393	553	1,434	1,376	1,343	1,032	1,698		5,185
Net loss	$ (2,631)	$ (1,140)	$ (2,473)	$ (1,642)	$ 65	$ (1,165)	$ (4,340)	$ (541)	$ (7,886)		$ (5,981)
Net loss per share, basic (in dollars per share)	$ (0.50)	$ (0.22)	$ (0.59)	$ (0.45)	$ 0.01	$ (0.35)	$ (1.36)	$ (0.18)
Net loss per share, diluted (in dollars per share)	$ (0.50)	$ (0.22)	$ (0.59)	$ (0.45)	$ 0.01	$ (0.35)	$ (1.36)	$ (0.18)
Weighted average shares of common shares outstanding:
Basic (in shares)	5,312	5,086	4,211	3,612	3,491	3,308	3,192	3,086	4,561	[1]	3,270	[1]
Diluted (in shares)	5,312	5,086	4,211	3,612	4,307	3,308	3,192	3,086	4,561	[1]	3,270	[1]

[1]       *Shares outstanding for prior periods have been restated for the 1-for-5 reverse stock split effective June 11, 2020.