Revenue Information - Revenue into Primary Product Groups and Major Regions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue [Line Items]
Revenue	$ 4,889	$ 6,264	$ 14,550	$ 21,184
North and South America [Member]
Revenue [Line Items]
Revenue	2,400	3,251	7,353	10,211
Asia Pacific (includes Middle East, India and Australia)
Revenue [Line Items]
Revenue	2,058	2,018	5,426	6,560
Europe and Africa [Member]
Revenue [Line Items]
Revenue	431	995	1,771	4,413
Audio conferencing [Member]
Revenue [Line Items]
Revenue	1,867	3,201	6,484	9,655
Microphones [Member]
Revenue [Line Items]
Revenue	2,355	2,475	6,239	8,525
Video products [Member]
Revenue [Line Items]
Revenue	$ 667	$ 588	$ 1,827	$ 3,004