Revenue From Contracts With Customers - Summary of Product and Service Revenue Disaggregated by Geographic Region (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]
Product and service revenue	$ 6,782	$ 4,577	$ 12,714	$ 9,507
United States
Disaggregation Of Revenue [Line Items]
Product and service revenue	3,942	1,625	7,380	4,439
South Korea
Disaggregation Of Revenue [Line Items]
Product and service revenue	1,190	768	2,188	1,406
Europe
Disaggregation Of Revenue [Line Items]
Product and service revenue	921	622	1,810	1,540
Asia (Excluding South Korea)
Disaggregation Of Revenue [Line Items]
Product and service revenue	633	1,561	1,175	1,985
Other
Disaggregation Of Revenue [Line Items]
Product and service revenue	$ 96	$ 1	$ 161	$ 137