Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 9,180	$ 3,708	$ 17,294	$ 8,371
United States
Disaggregation of Revenue [Line Items]
Total revenue	2,300	607	3,877	1,445
Greater China
Disaggregation of Revenue [Line Items]
Total revenue	5,222	2,596	10,209	5,320
Rest of North America
Disaggregation of Revenue [Line Items]
Total revenue	623	194	1,227	358
South America
Disaggregation of Revenue [Line Items]
Total revenue	294	84	595	269
Rest of Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	136	79	575	713
Europe
Disaggregation of Revenue [Line Items]
Total revenue	$ 605	$ 148	$ 811	$ 266