Accrued product warranty liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accrued product warranty liability [Roll Forward]
Balance, beginning of period	$ 101	$ 140
Warranties issued	6	5
Warranty settlements	(17)	(29)
Balance, end of period	90	$ 116
Accrued product warranty liability, current	72
Other Liabilities [Member]
Accrued product warranty liability [Roll Forward]
Accrued product warranty liability, non-current	$ 18
Maximum [Member]
Warranty [Abstract]
Product warranty period	24 months