Summary of Significant Accounting Policies - Revenue Recognition (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) business_line business_unit	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Disaggregation of Revenue [Line Items]
Leasing revenue	$ 300	$ 600
Total revenue	58,581	54,006
Contract assets	2,800		$ 1,300
Remaining performance obligation	$ 426,600
Number of business units | business_unit	2
Number of business lines | business_line	3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Disaggregation of Revenue [Line Items]
Remaining performance obligation, percentage	63.00%
Remaining performance obligation, term	12 months
Charging systems and installation
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,100	3,800
Extended warranty
Disaggregation of Revenue [Line Items]
Total revenue	$ 400	$ 300