Inventories - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Inventory
Inventory write-down			$ 687	$ 10,465
Chemistry Technologies
Inventory
Inventory write-down	$ 100	$ 5,900	500	2,000
Data Analytics
Inventory
Inventory write-down	$ 0	$ 3,900	$ 200	$ 3,900