Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Revenue Disaggregated by Geography

Revenue disaggregated by geography, based on the addresses of our customers, consists of the following (in thousands):

	Three Months Ended March 31,
	2022		2021
United States	$	51,967	$	52,569
Rest of World	6,614		1,437
	$	58,581	$	54,006

Concentration of Customer Risk

	Revenue		Accounts Receivable
	Three Months Ended March 31,		March 31,	December 31,
	2022	2021	2022	2021
Number of customers accounted for 10% or more*	2	3	3	1

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*Two customers accounted for 23% and 17%, respectively, of the Company's revenue for the three months ended March 31, 2022, respectively. No individual customer accounted for more than 20% of the Company’s revenue for the three months ended March 31, 2021, or accounts receivable as of March 31, 2022 and December 31, 2021.

Deferred Revenue

The changes in deferred revenue consisted of the following (in thousands):

Deferred revenue as of December 31, 2021	$	36,406
Revenue recognized from beginning balance during the three months ended March 31, 2022	(6,021)
Deferred revenue added during the three months ended March 31, 2022	4,358
Deferred revenue as of March 31, 2022	$	34,743

Revenue of Business Units

The revenue of business units are as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Proterra Transit	$	35,381	$	42,204
Proterra Powered & Energy	23,200		11,802
Total	$	58,581	$	54,006

Accrued Warranty Activity

Accrued warranty activity consisted of the following (in thousands):

	Three Months Ended March 31, 2022
Warranty reserve - beginning of period	$	23,274
Warranty costs incurred	(2,715)
Net changes in liability for pre-existing warranties, including expirations	(691)
Provision for warranty	2,813
Warranty reserve - end of period	$	22,681