Balance Sheet Components - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restricted cash	$ 2,000		$ 2,000		$ 1,300
Restricted cash, current	1,008	$ 276	1,008	$ 276	276
Restricted cash, non-current	1,004	1,280	1,004	1,280	1,004
Inventory write down	2,600		2,600		$ 2,700
Inventory write down	$ 700	$ 0	$ 866	$ 1,156