Inventories - Net loss incurred on valuation of inventory (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Inventories
Net loss incurred on valuation of inventory at lower of cost or market value and write-off of obsolete inventory	$ 3	$ 194	$ 105	$ 221