Financial Statement Components - Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 17,787	$ 13,540
Accumulated depreciation and amortization	(6,778)	(5,851)
Total property and equipment, net	11,009	7,689
Depreciation and amortization	3,900	2,500	$ 2,300
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	7,694	5,940
Computer hardware and software
Property, Plant and Equipment [Line Items]
Total property and equipment	2,854	2,450
Demonstration fleet and demonstration units
Property, Plant and Equipment [Line Items]
Total property and equipment	811	1,821
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	869	791
Vehicles
Property, Plant and Equipment [Line Items]
Total property and equipment	1,610	835
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	272	293
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,677	$ 1,410