Accrued expenses and other current liabilities (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Charging station expenses	$ 9,265,000	$ 5,393,000
Lease incentive liability	1,953,000	2,354,000
Employee related expenses	7,079,000	9,239,000
Other	1,347,000	1,038,000
Deposit liability	0	850,000
Accrued interest	0	1,294,000
Accrued expenses and other current liabilities	$ 19,644,000	$ 20,168,000