Proterra (PTRAQ) 10-Q 6 Nov 23 2023 Q3 Quarterly report Financial data

COVER

COVER - shares shares in Millions	9 Months Ended
	Sep. 30, 2023	Nov. 02, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-39546
Entity Registrant Name	Proterra Inc
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	90-2099565
Entity Address, Address Line One	1815 Rollins Road
Entity Address, City or Town	Burlingame
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94010
City Area Code	864
Local Phone Number	438-0000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		228.2
Central Index Key	0001820630
Amendment flag	false
Current fiscal year end date	--12-31
Document fiscal year focus	2023
Document fiscal period focus	Q3

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	[1]
Assets:
Cash and cash equivalents	$ 112,814	$ 73,695
Accounts receivable, net	80,854	130,337
Short-term investments	17,899	224,359
Inventory	263,610	169,567
Prepaid expenses and other current assets	33,532	50,893
Deferred cost of goods sold	4,706	4,304
Restricted cash, current	25,546	12,565
Total current assets	538,961	665,720
Property, plant, and equipment, net	108,409	107,552
Operating lease right-of-use assets	15,326	20,274
Long-term inventory prepayment	10,000	10,000
Other assets	38,729	36,913
Total assets	711,425	840,459
Liabilities and Stockholders’ Equity:
Accounts payable	7,379	57,822
Accrued liabilities	30,328	33,551
Deferred revenue, current	768	30,017
Operating lease liabilities, current	0	6,876
Debt, current	178,992	122,692
Total current liabilities	217,467	250,958
Deferred revenue, non-current	5	37,381
Operating lease liabilities, non-current	0	18,098
Other long-term liabilities	4,999	17,164
Total liabilities not subject to compromise	222,471	323,601
Liabilities subject to compromise	213,745	0
Total liabilities	436,216	323,601
Commitments and contingencies (Note 7)
Stockholders’ equity:
Common stock, $0.0001 par value; 1,000,000 shares authorized and 228,167 shares issued and outstanding as of September 30, 2023 (unaudited); 500,000 shares authorized and 226,265 shares issued and outstanding as of December 31, 2022	22	22
Preferred stock, $0.0001 par value; 10,000 shares authorized and zero shares issued and outstanding as of September 30, 2023 (unaudited); 10,000 shares authorized, zero shares issued and outstanding as of December 31, 2022	0	0
Additional paid-in capital	1,641,123	1,613,556
Accumulated deficit	(1,365,930)	(1,096,175)
Accumulated other comprehensive loss	(6)	(545)
Total stockholders’ equity	275,209	516,858
Total liabilities and stockholders’ equity	$ 711,425	$ 840,459
[1]Derived from audited Consolidated Financial Statements.

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,000,000,000	500,000,000
Common stock, shares issued (in shares)	228,167,279	226,265,000
Common stock, shares outstanding (in shares)	228,167,279	226,265,000
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total revenue	$ 86,148	$ 96,223	$ 251,391	$ 229,368
Total cost of goods sold	97,578	97,499	281,766	233,092
Gross loss	(11,430)	(1,276)	(30,375)	(3,724)
Research and development	10,992	18,165	44,438	44,871
Selling, general and administrative	37,419	38,554	108,867	98,646
Total operating expenses	48,411	56,719	153,305	143,517
Loss from operations	(59,841)	(57,995)	(183,680)	(147,241)
Interest expense, net	152	7,361	11,344	21,191
(Gain) loss on debt extinguishment	0	0	177,939	(10,201)
Gain on revaluation of derivative liability	(81,300)	0	(114,878)	0
Asset impairment charge	1,600	0	1,600	0
Other expense (income), net	(1,900)	(295)	(6,321)	(1,271)
Reorganization items, net	16,391	0	16,391	0
Income (loss) before income taxes	5,216	(65,061)	(269,755)	(156,960)
Provision for income taxes	0	0	0	0
Net income (loss)	$ 5,216	$ (65,061)	$ (269,755)	$ (156,960)
Net income (loss) per share of common stock:
Basic (in dollars per share)	$ 0.02	$ (0.29)	$ (1.19)	$ (0.70)
Diluted (in dollars per share)	$ 0.02	$ (0.45)	$ (1.19)	$ (0.79)
Weighted average shares used in per share computation:
Basic (in shares)	227,869	225,291	227,192	223,782
Diluted (in shares)	227,869	250,704	227,192	248,637
Product
Total revenue	$ 79,957	$ 89,769	$ 227,056	$ 214,196
Total cost of goods sold	92,950	91,408	264,391	217,743
Parts and other service
Total revenue	6,191	6,454	24,335	15,172
Total cost of goods sold	$ 4,628	$ 6,091	$ 17,375	$ 15,349

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,216	$ (65,061)	$ (269,755)	$ (156,960)
Available-for-sales securities:
Unrealized gain (loss) on available-for-sale securities	25	625	539	(1,481)
Other comprehensive income (loss), net of taxes	25	625	539	(1,481)
Total comprehensive income (loss), net of taxes	$ 5,241	$ (64,436)	$ (269,216)	$ (158,441)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	Total		Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2021			221,960
Beginning balance at Dec. 31, 2021	$ 720,152		$ 22	$ 1,578,943	$ (858,225)	$ (588)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon exercise of options and RSU release (in shares)			743
Issuance of stock upon exercise of options and RSU release	1,833			1,833
Stock-based compensation	4,642			4,642
Net (loss) income	(50,078)				(50,078)
Other comprehensive income (loss), net of taxes	(1,641)					(1,641)
Ending balance (in shares) at Mar. 31, 2022			222,703
Ending balance at Mar. 31, 2022	674,908		$ 22	1,585,418	(908,303)	(2,229)
Beginning balance (in shares) at Dec. 31, 2021			221,960
Beginning balance at Dec. 31, 2021	720,152		$ 22	1,578,943	(858,225)	(588)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(156,960)
Other comprehensive income (loss), net of taxes	(1,481)
Ending balance (in shares) at Sep. 30, 2022			225,532
Ending balance at Sep. 30, 2022	588,495		$ 22	1,605,727	(1,015,185)	(2,069)
Beginning balance (in shares) at Mar. 31, 2022			222,703
Beginning balance at Mar. 31, 2022	674,908		$ 22	1,585,418	(908,303)	(2,229)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon exercise of options and RSU release (in shares)			1,951
Issuance of stock upon exercise of options and RSU release	6,011			6,011
Stock issuance for employee stock purchase plan (in shares)			325
Stock issuance for employee stock purchase plan	1,502			1,502
Stock-based compensation	6,315			6,315
Net (loss) income	(41,821)				(41,821)
Other comprehensive income (loss), net of taxes	(465)					(465)
Ending balance (in shares) at Jun. 30, 2022			224,979
Ending balance at Jun. 30, 2022	646,450		$ 22	1,599,246	(950,124)	(2,694)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon exercise of options and RSU release (in shares)			553
Issuance of stock upon exercise of options and RSU release	1,125			1,125
Stock-based compensation	5,356			5,356
Net (loss) income	(65,061)				(65,061)
Other comprehensive income (loss), net of taxes	625					625
Ending balance (in shares) at Sep. 30, 2022			225,532
Ending balance at Sep. 30, 2022	588,495		$ 22	1,605,727	(1,015,185)	(2,069)
Beginning balance (in shares) at Dec. 31, 2022			226,265
Beginning balance at Dec. 31, 2022	516,858	[1]	$ 22	1,613,556	(1,096,175)	(545)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon exercise of options and RSU release (in shares)			588
Issuance of stock upon exercise of options and RSU release	113			113
Stock-based compensation	4,314			4,314
Debt extinguishment fair value adjustment	(7,200)			(7,200)
Net (loss) income	(243,977)				(243,977)
Other comprehensive income (loss), net of taxes	608					608
Ending balance (in shares) at Mar. 31, 2023			226,853
Ending balance at Mar. 31, 2023	270,716		$ 22	1,610,783	(1,340,152)	63
Beginning balance (in shares) at Dec. 31, 2022			226,265
Beginning balance at Dec. 31, 2022	516,858	[1]	$ 22	1,613,556	(1,096,175)	(545)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(269,755)
Other comprehensive income (loss), net of taxes	539
Ending balance (in shares) at Sep. 30, 2023			228,167
Ending balance at Sep. 30, 2023	275,209		$ 22	1,641,123	(1,365,930)	(6)
Beginning balance (in shares) at Mar. 31, 2023			226,853
Beginning balance at Mar. 31, 2023	270,716		$ 22	1,610,783	(1,340,152)	63
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon exercise of options and RSU release (in shares)			331
Stock issuance for employee stock purchase plan (in shares)			586
Stock issuance for employee stock purchase plan	662			662
Reclassification of liability upon charter amendment	20,800			20,800
Stock-based compensation	4,405			4,405
Net (loss) income	(30,994)				(30,994)
Other comprehensive income (loss), net of taxes	(94)					(94)
Ending balance (in shares) at Jun. 30, 2023			227,770
Ending balance at Jun. 30, 2023	$ 265,495		$ 22	1,636,650	(1,371,146)	(31)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon RSU release, net of payment of tax withholding obligations (in shares)	397
Issuance of stock upon RSU release, net of payment of tax withholding obligations	$ (9)
Stock-based compensation	4,482			4,482
Net (loss) income	5,216				5,216
Other comprehensive income (loss), net of taxes	25					25
Ending balance (in shares) at Sep. 30, 2023			228,167
Ending balance at Sep. 30, 2023	$ 275,209		$ 22	$ 1,641,123	$ (1,365,930)	$ (6)
[1]Derived from audited Consolidated Financial Statements.

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (269,755)	$ (156,960)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	15,045	9,583
Asset impairment charge	1,600	0
Stock-based compensation	13,201	16,313
Amortization of debt discount and issuance costs	(922)	10,497
Accretion of debt PIK interest	8,015	5,559
(Gain) loss on debt extinguishment	177,939	(10,007)
Gain on revaluation of derivative liability	(114,878)	0
Non-cash reorganization items	(1,139)	0
Others	(3,959)	(688)
Changes in operating assets and liabilities:
Accounts receivable	48,579	(20,717)
Inventory	(94,043)	(49,762)
Prepaid expenses and other current assets	17,360	(13,508)
Deferred cost of goods sold	(401)	(1,761)
Operating lease right-of-use assets and liabilities	(537)	412
Other assets	(3,522)	(13,042)
Accounts payable and accrued liabilities	41,880	19,922
Deferred revenue, current and non-current	16,420	5,100
Other non-current liabilities	9,859	1,473
Net cash used in operating activities	(139,258)	(197,586)
Cash flows from investing activities:
Purchase of investments	(164,468)	(395,596)
Proceeds from maturities of investments	375,832	512,000
Purchase of property and equipment	(16,486)	(41,833)
Net cash provided by investing activities	194,878	74,571
Cash flows from financing activities:
Repayment of government grants	0	(700)
Proceeds from exercise of stock options	113	8,969
Proceeds from employee stock purchase plan	662	1,502
Other financing activities	(4,295)	2,815
Net cash provided by (used in) financing activities	(3,520)	12,586
Net increase (decrease) in cash and cash equivalents, and restricted cash	52,100	(110,429)
Cash and cash equivalents, and restricted cash at the beginning of period	86,260	182,604
Cash and cash equivalents, and restricted cash at the end of period	138,360	72,175
Supplemental disclosures of cash flow information:
Cash paid for interest	4,400	6,289
Cash paid for income taxes	0	0
Non-cash investing and financing activity:
Accrued capital expenditures in accounts payable and accrued liabilities	3,299	4,798
Non-cash transfer of assets to inventory	0	515
Reclassification of derivative liability upon charter amendment	$ 20,800	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Organization and Description of Business Proterra Inc (“Proterra” or the “Company") is a leading developer and producer of zero-emission electric vehicle and EV technology solutions for commercial application. Proterra designs, develops, manufactures, and sells electric transit buses as an original equipment manufacturer for North American public transit agencies, airports, universities, and other commercial transit fleets. It also designs, develops, manufactures, sells, and integrates proprietary battery systems and electrification solutions for global commercial vehicle manufacturers. Additionally, Proterra provides fleet-scale, high-power charging solutions for its customers. Proterra is headquartered in Burlingame, California. The Company has consolidated bus production to Greenville, South Carolina and battery production to Greer, South Carolina as of September 30, 2023. Proterra Operating Company, Inc. (“Proterra OpCo” and formerly known as Proterra Inc prior to the consummation of the Business Combination (“Legacy Proterra”)) was originally formed in June 2004 as a Colorado limited liability company and converted to a Delaware corporation in February 2010. On June 14, 2021, Legacy Proterra consummated the transactions contemplated by the Merger Agreement (the “Merger Agreement”), dated as of January 11, 2021, by and among ArcLight Clean Transition Corp. (“ArcLight”), (and, after the domestication of ArcLight as a corporation incorporated in the State of Delaware, (the “Domestication”), Proterra), Phoenix Merger Sub, Inc. (the “Phoenix Merger Sub”), and Legacy Proterra, whereby Phoenix Merger Sub merged with and into Legacy Proterra, and Legacy Proterra being the surviving corporation and a wholly owned subsidiary of Proterra. Legacy Proterra changed its name to “Proterra Operating Company, Inc.” and continues as a Delaware corporation and wholly-owned subsidiary of Proterra (the “Merger”). Unless otherwise specified or unless the context otherwise requires, references in these notes to the “Company,” “we,” “us,” or “our” refer to Legacy Proterra prior to the Domestication, the Merger and other transactions contemplated by the Merger Agreement (the “Business Combination”) and to Proterra following the Business Combination. Voluntary Filing under Chapter 11 As previously disclosed, on August 7, 2023 (the “Petition Date”), Proterra Inc and its direct subsidiary, Proterra Operating Company, Inc. (collectively, the “Debtors”), filed voluntary petitions (the “Bankruptcy Petitions”) for reorganization under Chapter 11 (“Chapter 11) of the United States Bankruptcy Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the District of Delaware (such court, the “Bankruptcy Court” and such cases, the “Chapter 11 Cases”). The Chapter 11 Cases are jointly administered under the caption In re Proterra Inc , Case No. 23-11120 (BLS) (Bankr. D. Del. 2023). The Debtors continue to operate their business as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code and orders of the Bankruptcy Court. To ensure their ability to continue operating in the ordinary course of business, the Debtors sought from the Bankruptcy Court, various forms of “first-day” relief”, including, among other things, authority to use cash collateral, pay employee wages and benefits, pay vendors and suppliers in the ordinary course for all goods and services provided after the Petition Date and continue customer programs. On August 10, 2023, the motions filed by the Debtors seeking this “first-day” relief were approved by the Bankruptcy Court and, to the extent such relief was granted on an interim basis, the Debtors have subsequently obtained orders granting such relief on a final basis. For detailed discussion about the Chapter 11 Cases, refer to Note 2, Chapter 11 Filing and Other Related Matters. NASDAQ Delisting On August 8, 2023, the Company received written notice from the Listing Qualifications Department of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that, as a result of the Chapter 11 Cases and in accordance with Nasdaq Listing Rules 5101, 5110(b) and IM-5101-1, Nasdaq had determined to delist the Company’s common stock from the Nasdaq Global Select Market. The Company did not appeal this determination. On August 17, 2023, Nasdaq suspended the trading of the Company’s common stock at the opening of business. On September 9, 2023, Nasdaq applied to the U.S. Securities and Exchange Commission (the “SEC”) pursuant to Form 25 to remove the common stock of the Company from listing and registration on the Nasdaq Global Select Market at the opening of business September 20, 2023. As a result of the suspension and delisting, the Company’s common stock began trading exclusively on the over-the-counter market (“OTC market”) on August 17, 2023 under the symbol PTRAQ. We will remain subject to SEC reporting obligations. Application of ASC 852 Beginning on the Petition Date, the Company applied Financial Accounting Standards Board Codification Topic 852, Reorganizations (“ASC 852”) in preparing the consolidated financial statements. ASC 852 requires the financial statements, for the periods subsequent to the Petition Date and up to and including the period of emergence from Chapter 11, to distinguish transactions and events that are directly associated with the reorganization from the ongoing operations of the business. Accordingly, certain charges incurred during the bankruptcy proceedings, such as legal and other professional fees incurred directly as a result of the bankruptcy proceeding are recorded as Reorganization items, net in the Condensed Consolidated Statements of Operations and Comprehensive Loss. In addition, prepetition obligations that may be impacted by the Chapter 11 process have been classified on the Consolidated Balance Sheet as of September 30, 2023 as liabilities subject to compromise. These liabilities are reported at the amounts the Company anticipates will be allowed by the Bankruptcy Court, even if they may be settled for lesser amounts. See Note 2, Chapter 11 Filing and Other Related Matters, for more information. Basis of Presentation The unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and the rules and regulations of the SEC. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2022 and the related notes incorporated by reference in the Company’s Annual Report (the “Annual Report”) on Form 10-K, filed with SEC on March 17, 2023 and amended on May 1, 2023, which provides a more complete discussion of the Company’s accounting policies and certain other information. The information as of December 31, 2022 was derived from the Company’s audited financial statements. The condensed consolidated financial statements were prepared on the same basis as the audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for a fair presentation of the Company’s financial position as of September 30, 2023 and the results of operations and cash flows for the nine months ended September 30, 2023 and 2022. The results of operations for the nine months ended September 30, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023. Liquidity and Going Concern Under ASC Subtopic 205-40, Presentation of Financial Statements—Going Concern (“ASC 205-40”), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about the Company’s ability to meet our future obligations as they become due within one year of the financial statements being issued in this Quarterly Report on Form 10-Q. These financial statements have been prepared by management in accordance with U.S. GAAP and this basis assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. These financial statements do not include any adjustments that may result from the outcome of this uncertainty. The Company has incurred net losses and negative cash flows from operations since inception. As of September 30, 2023, the Company has an accumulated deficit of $1.4 billion, and cash and cash equivalents and short-term investments of $130.7 million. The Company has funded operations primarily through a combination of equity and debt financing. Beginning on the Petition Date, the Company’s ability to continue as a going concern is contingent upon, among other things, its ability to, subject to the Bankruptcy Court’s approval, implement a Chapter 11 plan, emerge from the Chapter 11 Cases and generate sufficient liquidity to meet its contractual obligations and operating needs. As a result of risks and uncertainties, the delisting of our common stock and the effects of potential disruption resulting from the Chapter 11 Cases making it more difficult to maintain business, financing and operational relationships, together with the Company’s recurring losses from operations and accumulated deficit, substantial doubt exists regarding our ability to continue as a going concern for the next 12 months. See Note 2, Chapter 11 Filing and Other Related Matters for additional details on the Chapter 11 Cases. The Company expects to continue to operate in the normal course for the duration of the Chapter 11 Cases. The Bankruptcy Court has approved a bidding process that may result in the sale of all or substantially all of its assets during the Chapter 11 Cases. Use of Estimates In preparing the condensed consolidated financial statements and related disclosures in conformity with U.S. GAAP and pursuant to the rules and regulations of the SEC, the Company must make estimates and judgments that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results may differ materially from these estimates. Significant Accounting Policies There have been no changes to the Company’s significant accounting policies described in the Annual Report, except for the accounting policies related to the Secured Convertible Promissory Notes that Legacy Proterra issued in August 2020 (as amended and restated, the “Convertible Notes”) and derivative liability described in Note 5, Debt, adopted during the three months ended March 31, 2023, and application of ASC 852 during the three months ended September 30, 2023, that have had a material impact on the Company’s condensed consolidated financial statements and related notes. See Note 2, Chapter 11 Filing and Other Related Matters, for more information on application of ASC 852. Segments The Company operates in the United States and has sales to the European Union, Canada, United Kingdom, Australia, Japan and Türkiye. Revenue disaggregated by geography, based on the addresses of the Company’s customers, consists of the following (in Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 United States $ 68,480 $ 82,040 $ 201,585 $ 195,680 Rest of World 17,668 14,183 49,806 33,688 $ 86,148 $ 96,223 $ 251,391 $ 229,368 The Company’s chief operating decision maker is its Chief Executive Officer (CEO) who reviews financial information presented on a consolidated basis for purposes of making decision on allocating resources and assessing financial performance. Accordingly, the Company has determined that it has a single reportable segment. Accounts Receivable and Allowance for Credit Losses Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company determines the allowance for credit losses based on historical write-off experience, an analysis of the aging of outstanding receivables, customer payment patterns and expectations of changes in macroeconomic conditions that may affect the collectability of outstanding receivables. The allowance for credit losses was not material as of September 30, 2023 and December 31, 2022. Credit Risk and Concentration The Company’s financial instruments that are potentially subject to concentrations of credit risk consist primarily of cash, cash equivalents, restricted cash, short-term investments, and accounts receivable. Cash and cash equivalents and short-term investments are maintained primarily at one financial institution as of September 30, 2023 and December 31, 2022, and deposits exceed federally insured limits. Risks associated with cash and cash equivalents, and short-term investments are mitigated by banking with creditworthy financial institutions. The Company has not experienced any losses on its deposits of cash and cash equivalents or its short-term investments. Cash equivalents and short-term investments consist of short-term money market funds, corporate debt securities, and debt securities issued by the U.S. Treasury, which are deposited with reputable financial institutions. The Company’s cash management and investment policy limits investment instruments to securities with short-term credit ratings at the timing of purchase of P-2 and A-2 or better from Moody’s Investors Service and Standard & Poor’s Financial Services, LLC, respectively, with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations. Accounts receivable are typically unsecured and are generally derived from revenue earned from transit agencies, universities and airports in North America and global commercial vehicle manufacturers in North America, the European Union, the United Kingdom, Australia, Japan and Türkiye. The Company periodically evaluates the collectability of its accounts receivable and provides an allowance for potential credit losses as necessary. Given the large order value for customers and the relatively low number of customers, revenue and accounts receivable have typically been concentrated with a limited number of customers. Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, December 31, 2023 2022 2023 2022 2023 2022 Number of customers accounted for 10% or more 3 2 1 2 3 2 Total % of customers accounted for 10% or more 62% 40% 24% 27% 52% 48% Single source suppliers provide the Company with a number of components that are required for manufacturing of its current products. Although there may be multiple suppliers available, many of the components that the Company’s manufacturing process requires are purchased from one single source. If these single source suppliers fail to meet the Company’s requirements on a timely basis at competitive prices or are unable to provide components for any reason, the Company could suffer manufacturing delays, a possible loss of revenue, or incur higher cost of sales, any of which could adversely impact the Company’s operating results. As part of the Chapter 11 proceedings, the Company rejected the existing contract with TPI Composites, Inc., the single source supplier for bus bodies, and the Company may be unable to negotiate another agreement on better terms. As of September 30, 2023, the Company has sufficient bus bodies in inventory to meet its near term production plan. Impairment of Long-Lived Assets The Company evaluates the recoverability of property, plant, and equipment and right-of-use assets for possible impairment whenever events or circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of these assets is measured by a comparison of the carrying amounts to the future undiscounted cash flows the assets are expected to generate. If such review indicates that the carrying amount of long-lived assets is not recoverable, the carrying amount of such assets is reduced to fair value. In addition to the recoverability assessment, the Company periodically reviews the remaining estimated useful lives of property, plant, and equipment. If the estimated useful life assumption for any asset is reduced, the remaining net book value is depreciated over the revised estimated useful life. The Company reviews long-lived assets for impairment at the lowest level for which separate cash flows can be identified. On October 17, 2023, Volta Trucks, a Proterra Powered customer, announced that it will file for administration in the United Kingdom and insolvency proceedings in other relevant jurisdictions. The Company recorded a $1.6 million impairment charge in the three months and nine months ended September 30, 2023 to the long-term investments recorded in other assets in the condensed consolidated balance sheets. See Note 12, Subsequent events, for details. No impairment charge was recognized in the three and nine months ended September 30, 2022. Deferred Revenue Deferred revenue consists of billings or payments received in advance of revenue recognition that are recognized as revenue once the revenue recognition criteria are met. In some instances, progress billings are issued upon meeting certain milestones stated in the contracts. Accordingly, the deferred revenue balance does not represent the total contract value of non-cancelable arrangements. Invoices are typically due within 30 to 40 days. The current portion of deferred revenue represents the amount that is expected to be recognized as revenue within one year from the balance sheet date. The changes in deferred revenue inclusive of the balance recorded in the liabilities subject to compromise, consisted of the following (in thousands): Deferred revenue as of December 31, 2022 $ 67,398 Revenue recognized from beginning balance during the nine months ended September 30, 2023 (17,336) Deferred revenue added during the nine months ended September 30, 2023 33,756 Deferred revenue as of September 30, 2023 $ 83,818 Liabilities Subject to Compromise Since filing the Chapter 11 petitions, the Company has operated as debtor-in-possession under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code. The liabilities subject to compromise balance is reflective of expected allowed claim amounts in accordance with ASC 852 and are subject to change materially based on the proceedings and continued consideration of claims that may be modified, allowed, or disallowed. Refer to Note 2, Chapter 11 Filing and Other Related Matters, for details. Revenue Recognition The Company derives revenue primarily from the sale of vehicles and charging systems, the installation of charging systems, the sale of battery systems and powertrain components to other vehicle manufacturers, as well as the sale of spare parts and other services provided to customers. Product revenue consists of revenue earned from vehicles and charging systems, battery systems and powertrain components, installation of charging systems, and revenue from leased vehicles, charging systems, and batteries under operating leases. Parts and other service revenue includes revenue earned from spare parts, the design and development of battery systems and powertrain systems for other vehicle manufacturers, and extended warranties. The Company recognizes revenue when or as it satisfies a performance obligation by transferring control of a product or service to a customer. Revenue from product sales is recognized when control of the underlying performance obligations is transferred to the customer. Revenue from sales of vehicles is typically recognized upon delivery when the Company can objectively demonstrate that the criteria specified in the contractual acceptance provisions are achieved prior to delivery. In cases, where the Company cannot objectively demonstrate that the criteria specified in the contractual acceptance provisions have been achieved prior delivery, revenue is recognized upon acceptance by the customer. Revenue from sales of charging systems is recognized at a point in time, generally upon delivery or commissioning when control of the underlying performance obligations are transferred to the customer. Under certain contract arrangements, the control of the performance obligations related to the charging systems is transferred over time, and the associated revenue is recognized over the installation period using an input measure based on costs incurred to date relative to total estimated costs to completion. Spare parts revenue is recognized upon shipment. Extended warranty revenue is recognized over the life of the extended warranty using the time elapsed method. Development service contracts typically include the delivery of prototype products to customers. The performance obligation associated with the development of prototype products as well as battery systems and powertrain components to other vehicle manufacturers, is satisfied at a point in time, typically upon shipping. Revenue derived from performance obligations satisfied over time from charging systems and installation was $0.9 million and $3.7 million for the three months ended September 30, 2023 and 2022, respectively, and $3.7 million and $5.8 million for the nine months ended September 30, 2023 and 2022, respectively. Leasing revenue and extended warranty revenue recognized over time was immaterial for the three and nine months ended September 30, 2023 and 2022, respectively. As of September 30, 2023 and December 31, 2022, the contract assets balance was $3.2 million and $26.1 million, respectively, and these balances are recorded in the prepaid expenses and other current assets on the consolidated balance sheets. The contract assets are expected to be billed within the next twelve months. As of September 30, 2023, the amount of remaining performance obligations that have not been recognized as revenue was $417.4 million. As the Company is in the process of a Bankruptcy Court-approved bidding process that may result in the sale of all or substantially all of its assets during the Chapter 11 Cases, the timing of satisfaction of these performance obligations is not estimable as of September 30, 2023. This amount excludes the value of remaining performance obligations for contracts with an original expected length of one year or less. Our business has the following commercial offerings each addressing a critical component of commercial vehicle electrification. • Proterra Transit designs, develops, manufactures, and sells electric transit buses as an original equipment manufacturer (“OEM”) for North American public transit agencies, airports, universities, and other commercial transit fleets. • Proterra Powered & Energy includes Proterra Powered, which designs, develops, manufactures, sells, and integrates proprietary battery systems and electrification solutions into vehicles for global commercial vehicle OEMs, and Proterra Energy, which offers turnkey fleet-scale, high-power charging solutions and software services, ranging from fleet and energy management software-as-a-service, to fleet planning, hardware, infrastructure, installation, utility engagement, and charging optimization. Revenue of these commercial offerings are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Proterra Transit $ 25,770 $ 56,363 $ 91,745 $ 142,563 Proterra Powered & Energy 60,378 39,860 159,646 86,805 Total $ 86,148 $ 96,223 $ 251,391 $ 229,368 Product Warranties Warranty expense is recorded as a component of cost of goods sold. Activity of the accrued warranty inclusive of the balances in the liabilities subject to compromise, consisted of the following (in thousands): Nine Months Ended September 30, 2023 Warranty reserve- beginning of period $ 25,513 Warranty costs incurred (2,991) Net changes in liability for pre-existing warranties, including expirations (3,000) Provision for warranty 13,501 Warranty reserve- end of period $ 33,023 Adopted Accounting Guidance and Accounting Pronouncements Not Yet Effective There have been no recent accounting pronouncements, changes in accounting pronouncements or recently adopted accounting guidance during the nine months ended September 30, 2023 that are of significance or potential significance to the Company.

Chapter 11 Filing and Other Rel

Chapter 11 Filing and Other Related Matters	9 Months Ended
	Sep. 30, 2023
Reorganizations [Abstract]
Chapter 11 Filing and Other Related Matters	Chapter 11 Filing and Other Related Matters The Chapter 11 Cases Events Leading to Chapter 11 As previously disclosed, the Company has incurred net losses and negative cash flows from operations since inception and has funded operations primarily through a combination of equity and debt financing. The Company’s (i) existing Convertible Notes include a requirement that the Company maintain minimum liquidity and (ii) existing loan facilities include a requirement that the Company deliver financial reports without a going concern qualification, which have been waived or modified as the Company pursued various strategies designed to improve liquidity and cash generated from operations, such as expense reduction and cash savings initiatives that included streamlining facilities, initiating working capital initiatives, and efforts to reduce overall selling, general and administrative expenses, including a workforce reduction announced in January 2023, that included the closure of the City of Industry facility by December 31, 2023 to improve operational efficiency, and the cessation of battery production in the Burlingame facility in June 2023 to consolidate all battery production in our Powered 1 battery factory in the second half of 2023. Additionally, the Company explored potential options for raising additional funds through the issuance of equity, equity-linked, and/or debt securities, debt financings or other capital sources and/or strategic transactions. However, as discussed in the Declaration of Gareth T. Joyce in Support of Chapter 11 Petitions and First Day Pleadings [Docket No. 16] (the “First Day Declaration”) filed by the Debtors’ in the Chapter 11 Cases, these prepetition capital raising efforts were unsuccessful. Voluntary Filing for Chapter 11 Protections As previously disclosed, on the Petition Date, the Debtors filed the Bankruptcy Petitions for reorganization under Chapter 11 of the United States Bankruptcy Code in the Bankruptcy Court. The Chapter 11 Cases are jointly administered under the caption In re Proterra Inc , Case No. 23-11120 (BLS) (Bankr. D. Del. 2023). The Debtors continue to operate their business as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code and orders of the Bankruptcy Court. To ensure their ability to continue operating in the ordinary course of business, the Debtors sought, from the Bankruptcy Court, various forms of “first-day” relief, including, among other things, authority to use cash collateral, pay employee wages and benefits, pay vendors and suppliers in the ordinary course for all goods and services provided after the Petition Date and continue customer programs. On August 10, 2023, the motions filed by the Debtors seeking this “first-day” relief were approved by the Bankruptcy Court and, to the extent such relief was granted on an interim basis, the Debtors have subsequently obtained orders granting such relief on a final basis. As previously disclosed by the Company, the filing of the Bankruptcy Petitions constituted an event of default that accelerated the Company’s obligations under the Senior Credit Facility and the Convertible Notes. A s a result of the bankruptcy filing, the outstanding principal and interest thereunder became immediately due and payable. Any efforts to enforce such payment obligations under the debt instruments set forth above are automatically stayed under the Bankruptcy Code. However, the Convertible Notes continue to accrue PIK and cash interest under the cash collateral order. See Note 5, Debt for details. Debtors-In-Possession The Debtors are currently operating as debtors-in-possession in accordance with the applicable provisions of the Bankruptcy Code. In general, as debtors-in-possession under the Bankruptcy Code, the Debtors are authorized to continue to operate as an ongoing business, but may not engage in transactions outside the ordinary course of business without the prior approval of the Bankruptcy Court. The Debtors have obtained relief from the Bankruptcy Court authorizing the Debtors to conduct their business activities in the ordinary course, including, among other things and subject to the terms and conditions of such orders, authorizing the Debtors to, among other things: (i) pay employees’ wages and related obligations; (ii) pay pre-petition claims of certain lien claimants and critical vendors; (iii) continue to operate their cash management system in a manner substantially similar to pre-petition practice (iv) continue to maintain and administer certain existing customer programs; (v) pay taxes in the ordinary course; (vi) maintain their insurance program and surety bond program in the ordinary course; (vii) pay utility providers for post-petition services in the ordinary course; and (viii) to use cash collateral. In addition, the Bankruptcy Court has entered an order limiting trading of the Company’s equity securities to protect the Company’s net operating losses. Marketing Process In addition to the aforementioned first-day motions, the Debtors received Bankruptcy Court approval of certain procedures related to a marketing and bidding process for one or more potential sales or reorganization of all or certain assets of the Debtors, including the assets of Debtors’ Proterra Transit, Proterra Powered, and Proterra Energy business lines. Prepetition Key Employee Retention Plan As previously disclosed by the Company, on August 3, 2023, the compensation committee of the board of directors of the Company (the “Compensation Committee”) granted retention awards (each, a “Retention Award”) to certain of the Company’s employees. The Retention Awards, memorialized in an award letter (“Retention Award Letter”), are subject to clawback if the participant is terminated for cause or voluntarily resigns before the earlier of either the six-month anniversary or one-year anniversary of the date of grant, as applicable, or any potential transaction involving the Company (including through a merger, recapitalization or sale of substantially all of the assets of the Company) or any sale, disposition or winding down of any business unit, business division or asset of the Company that the participant provides substantially all of his or her services to. As previously disclosed, the Company granted Retention Awards to named executive officers Julian Soell and Chris Bailey. Messrs. Soell and Bailey each received a Retention Award of approximately $0.5 million, which was paid on August 4, 2023, subject to certain clawback provisions. Under the terms of Messrs. Soell’s and Bailey’s Retention Award Letters, if the executive is terminated by the Company for “cause” (as defined in the Retention Award Letter) or by the executive without “good reason” (as defined in the executive’s employment or severance agreement) prior to the earlier of (i) August 4, 2024 and (ii) a “corporate transaction” (as defined in the Retention Award Letter), the executive will be required to repay the Company the after-tax amount of the Retention Award within 90 days following his termination date. Such repayment obligation does not apply in the event of a termination due to a death or disability, or due to a leave of absence because of a disability. Automatic Stay Subject to certain specific exceptions under the Bankruptcy Code, the Debtors’ filing of the Bankruptcy Petitions resulted in most judicial or administrative actions against the Debtors and efforts by creditors to collect on or otherwise exercise rights or remedies with respect to pre-petition claims being subject to the automatic stay under the Bankruptcy Code. Executory Contracts Subject to certain exceptions, under the Bankruptcy Code, the Debtors may assume, assume and assign, or reject certain executory contracts and unexpired leases subject to the approval of the Bankruptcy Court and certain other conditions. Generally, the rejection of an executory contract or unexpired lease is treated as a pre-petition breach of such executory contract or unexpired lease and, subject to certain exceptions, relieves the Debtors from performing their future obligations under such executory contract or unexpired lease but entitles the contract counterparty or lessor to a pre-petition general unsecured claim for damages caused by such deemed breach. Generally, the assumption of an executory contract or unexpired lease requires the Debtors to cure existing monetary defaults under such executory contract or unexpired lease and provide adequate assurance of future performance. Accordingly, any description of an executory contract or unexpired lease with the Debtors in this document, including where applicable a quantification of the Company’s obligations under any such executory contract or unexpired lease of the Debtors, is qualified by any rights the Debtors have under the Bankruptcy Code. Potential Claims The Debtors have filed with the Bankruptcy Court schedules and statements setting forth, among other things, the assets and liabilities of each of the Debtors, subject to the assumptions filed in connection therewith. These schedules and statements may be subject to further amendment or modification after filing. Certain holders of pre-petition claims against the Debtors are required to file proofs of claim by the deadlines set forth in the Order Establishing Bar Dates for Filing Proofs of Claim and Approving the Form and Manner of Notice Thereof [Docket No. 187]. The Debtors will receive proofs of claim, that will be reconciled to amounts recorded in the Debtors’ accounting records. Differences in amounts recorded and claims filed by creditors will be investigated and resolved, including through the filing of objections with the Bankruptcy Court, where appropriate. The Debtors may ask the Bankruptcy Court to disallow claims that the Debtors believe are duplicative, have been later amended or superseded, are without merit, are overstated or should be disallowed for other reasons. In addition, as a result of this process, the Debtors may identify additional liabilities that will need to be recorded or reclassified to liabilities subject to compromise. In light of the substantial number of claims expected to be filed, the claims administration process may take considerable time to complete and may continue through and following the Chapter 11 proceedings. Reorganization items, net and Liabilities Subject to Compromise The amounts currently classified as liabilities subject to compromise may be subject to future adjustments depending on Bankruptcy Court actions, further developments with respect to disputed claims, determinations of secured status of certain claims, the values of any collateral securing such claims, or other events. Any resulting changes in classification will be reflected in subsequent financial statements. If there is uncertainty about whether a secured claim is undersecured, or will be impaired under any Chapter 11 plan, the entire amount of the claim is included with prepetition claims in liabilities subject to compromise. As a result of the filing of the Chapter 11 Cases on August 7, 2023, the classification of pre-petition indebtedness is generally subject to compromise pursuant to a Chapter 11 plan. Generally, actions to enforce or otherwise effect payment of pre-bankruptcy filing liabilities are stayed. Although payment of pre-petition claims generally is not permitted, the Bankruptcy Court granted the Debtors authority to pay certain pre-petition claims in designated categories and subject to certain terms and conditions. This relief generally was designed to preserve the value of the Debtors’ business and assets. Among other things, the Bankruptcy Court authorized the Debtors to pay certain pre-petition claims relating to employee wages and benefits, taxes and critical vendors. The Debtors are paying and intend to pay undisputed post-petition liabilities in the ordinary course of business. In addition, the Debtors may reject certain pre-petition executory contracts and unexpired leases with respect to their operations with the approval of the Bankruptcy Court. Any damages resulting from the rejection of executory contracts and unexpired leases are treated as general unsecured claims. Reorganization items, net incurred as a result of the Chapter 11 Cases presented separately in the accompanying Consolidated Statements of Operations were as follows (in thousands): Three Months Ended September 30, 2023 Nine Months Ended September 30, 2023 Professional fees and other bankruptcy related costs $ 17,530 $ 17,530 Write-off of liabilities subject to compromise (1,139) (1,139) Reorganization items, net $ 16,391 $ 16,391 As of September 30, 2023, no cash payment was made for the legal and professional fees related to the reorganization. The accompanying Condensed Consolidated Balance Sheets as of September 30, 2023 include amounts classified as Liabilities subject to compromise. The amount reflects the expected allowed amount of the pre- petition claims that are not fully secured and that have at least a possibility of not being repaid at the full claim amount. Liabilities subject to compromise consisted of the following (in thousands): September 30, 2023 Accounts payable $ 73,947 Accrued liabilities 14,885 Deferred revenue 83,045 Operating lease liabilities 19,490 Other liabilities 22,378 Liabilities subject to compromise $ 213,745 The Company will continue to evaluate the amount and classification of its pre-petition liabilities. Any additional liabilities that are subject to compromise will be recognized accordingly and the aggregate amount of liabilities subject to compromise may change and such adjustments may be material.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company measures certain financial assets and liabilities at fair value. Fair value is determined based on the exit price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is estimated by applying the following hierarchy: Level 1 – Quoted prices in active markets for identical assets or liabilities; Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability. Financial assets and liabilities measured at fair value on a recurring basis using the above input categories were as follows (in thousands): Pricing Category Fair Value at September 30, 2023 December 31, 2022 Assets: Cash equivalents and marketable securities: Money market funds Level 1 $ 9 $ 14,941 Short-term investments: U.S. Treasury securities Level 1 17,899 224,359 Total $ 17,908 $ 239,300 The Company’s short-term investments were comprised of U.S. Treasury securities, and classified as available-for-sale at the time of purchase because it is intended that these investments are available for current operations. Investments are reported at fair value and are subject to periodic impairment review. Unrealized gains and losses related to changes in the fair value of these securities are recognized in accumulated other comprehensive loss. The ultimate value realized on these securities is subject to market price volatility until they are sold. Realized gains or losses from short-term investments are recorded in other expense (income), net. As of September 30, 2023 and December 31, 2022, the Company has $25.0 million and $26.6 million, respectively, of long-term investments recorded in other assets in the condensed consolidated balance sheets, comprised of minority ownership of equity investments in privately held entities. The long-term investment balances include $25.0 million strategic equity investment made in the third quarter of 2022 in an entity that the Company expects to produce lithium iron phosphate (LFP) battery cells in the United States in the coming years which is expected to provide the Company with development opportunities for battery packs with another cell chemistry to address additional segments of the commercial vehicle market. These investments do not have a readily determinable fair value and are accounted for under a measurement alternative at cost, less impairment, adjusted for observable price changes. No impairment charges or observable price changes were recognized in the nine months ended September 30, 2022. The Company recorded a $1.6 million impairment charge to write off its entire investment in Volta Trucks entity in the nine months ended September 30, 2023 as a result of its filing for insolvency proceedings. See Note 12, Subsequent events, for details. There are no unrealized gains or losses associated with the long-term investment as of September 30, 2023. The following is a summary of cash equivalents and marketable securities as of September 30, 2023 (in thousands): Amortized Cost Unrealized Loss Estimated Fair Value Cash equivalents: Money market funds $ 9 $ — $ 9 Short-term investments: U.S. Treasury securities 17,905 (6) 17,899 Total $ 17,914 $ (6) $ 17,908 As of September 30, 2023, the contractual maturities of the short-term investments were less than one year. The following is a summary of cash equivalents and marketable securities as of December 31, 2022 (in thousands): Amortized Cost Unrealized Loss Estimated Fair Value Cash equivalents: Money market funds $ 14,941 $ — $ 14,941 Short-term investments: U.S. Treasury securities 224,904 (545) 224,359 Total $ 239,845 $ (545) $ 239,300 As of December 31, 2022, the contractual maturities of the short-term investments were less than one year. The fair value of derivative liability under the Convertible Notes was measured as the difference between the estimated value of the Convertible Notes with and without the embedded features. See Note 5, Debt, for additional information on the Convertible Notes. A summary of the changes of the derivative liability is as follows (in thousands): Derivative liability Fair value at issuance as of March 31, 2023 $ 135,678 Change in fair value (114,878) Reclassification of liability upon charter amendment (20,800) Fair value as of September 30, 2023 $ — The change in fair value of derivative liability is recorded in the statements of operations. On June 23, 2023, the Company received stockholder approval to increase the number of authorized shares and subsequently filed a

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Cash and cash equivalents consisted of the following (in thousands): September 30, 2023 December 31, 2022 Cash $ 112,805 $ 58,754 Cash equivalents 9 14,941 Total cash and cash equivalents $ 112,814 $ 73,695 The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets to the total of such amounts shown on the statements of cash flows. The restricted cash is primarily collateral for performance bonds issued to certain customers. The collateral is provided in the form of a cash deposit to either support the bond directly or to collateralize a letter of credit that supports the performance bonds. September 30, 2023 December 31, 2022 Cash and cash equivalents $ 112,814 $ 73,695 Restricted cash, current portion 25,546 12,565 Total cash and cash equivalents, and restricted cash $ 138,360 $ 86,260 Inventories consisted of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 204,463 $ 127,199 Work in progress 39,736 21,153 Finished goods 10,201 13,518 Service parts 9,210 7,697 Total inventories $ 263,610 $ 169,567 Increases in Raw materials as of September 30, 2023 is primarily related to the timing of receipts of lithium-ion cells for our battery packs and increase of work in progress and finished goods mainly due to timing of bus deliveries. For the three and nine months ended September 30, 2023, $7.8 million and $14.5 million of expenses were recorded related to the write down of inventories for excess or obsolete inventories, scrap from the battery manufacturing facility (Powered 1) ramp up production and consolidation of Powered facilities, and lower of cost or market adjustment. The reserve expenses were immaterial for each of the three and nine months ended September 30, 2022. Property, plant, and equipment, net, consisted of the following (in thousands): September 30, 2023 December 31, 2022 Computer hardware $ 6,116 $ 5,465 Computer software 17,111 11,012 Internally used vehicles and charging systems 11,778 15,177 Leased vehicles and batteries 5,142 5,142 Leasehold improvements 30,951 10,716 Machinery and equipment 80,795 28,942 Office furniture and equipment 3,397 2,523 Tooling 19,885 22,430 Finance lease right-of-use assets 878 179 Construction in progress 5,217 72,505 181,270 174,091 Less: Accumulated depreciation and amortization (72,861) (66,539) Total $ 108,409 $ 107,552 Construction in progress was comprised of various assets that are not available for their intended use as of the balance sheet date. The construction in progress balance as of December 31, 2022 mainly related to the equipment and facility build out at Powered 1 in Greer, South Carolina. For the three and nine months ended September 30, 2023, depreciation and amortization expense were $5.5 million and $15.0 million, respectively. For the three and nine months ended September 30, 2022, depreciation and amortization expense were $2.9 million and $9.6 million, respectively. Accrued liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued payroll and related expenses $ 4,819 $ 8,647 Accrued legal and professional fees 17,649 1,586 Accrued sales and use tax 168 1,784 Warranty reserve — 8,406 Accrued supplier liability — 7,699 Insurance related — 4,445 Other accrued expenses 7,692 984 Total $ 30,328 $ 33,551 Other long-term liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Warranty reserve $ 3,420 $ 17,107 Other long-term liabilities 1,579 57 Total $ 4,999 $ 17,164

Debt

Debt	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt	Debt Debt, net of debt discount and issuance costs, consisted of the following (in thousands): September 30, 2023 December 31, 2022 Senior Credit Facility $ — $ — Convertible Notes 178,992 122,692 Total debt $ 178,992 $ 122,692 Less debt, current 178,992 122,692 Debt, non-current $ — $ — Senior Credit Facility In May 2019, the Company entered into the Senior Credit Facility with borrowing capacity up to $75.0 million. The commitment under the Senior Credit Facility is available to the Company on a revolving basis through the earlier of May 9, 2024 or 91 days prior to the stated maturity of any subordinated debt in aggregate amount of $7.5 million or more. The maximum availability under the Senior Credit Facility is based on certain specified percentage of eligible accounts receivable and inventory, subject to certain reserves, to be determined in accordance with the Senior Credit Facility. The Senior Credit Facility includes a $25.0 million letter of credit sub-line. Subject to certain conditions, the commitment may be increased by $50.0 million upon approval by the lender, and at the Company’s option, the commitment can be reduced to $25.0 million or terminated upon at least 15 days’ written notice. The Senior Credit Facility is secured by a security interest in substantially all of the Company’s assets except certain excluded assets. Borrowings under the Senior Credit Facility bore interest at per annum rates equal to, at the Company’s option, either (i) the base rate plus an applicable margin for base rate loans, or (ii) the London Interbank Offered Rate (“LIBOR”) plus an applicable margin for LIBOR loans. The base rate is calculated as the greater of (a) the Lender prime rate, (b) the federal funds rate plus 0.5%, and (c) one-month LIBOR plus 1.0%. The applicable margin is calculated based on a pricing grid linked to quarterly average excess availability (as a percentage of borrowing capacity). For base rate loans, the applicable margin ranges from 0.0% to 1.5%, and for LIBOR loans, it ranges from 1.5% to 3.0%. The Senior Credit Facility contains certain customary non-financial covenants. In addition, the Senior Credit Facility requires the Company to maintain a fixed charge coverage ratio of at least 1.00:1.00 during such times as a covenant trigger event shall exist. On April 3, 2023, the Company entered into the Third Amendment to the Senior Credit Facility to replace the references of LIBOR in the loan document with Term SOFR, a rate based on the secured overnight financing rate as administered by the Federal Reserve Bank of New York. The voluntary petition filing on August 7, 2023 is considered an event of default under the Senior Credit Facility, and resulted in termination of the revolver commitment. The defeasance of the Senior Credit Facility resulted in the write-off of remaining unamortized debt issuance cost of $0.1 million to interest expense. There was no outstanding balance for borrowings under the Senior Credit Facility as of September 30, 2023 and December 31, 2022. The Company elected to cash collateralize its outstanding letters of credit obligations in accordance with certain terms under the Senior Credit Facility, which was recorded in the restricted cash, current on the condensed consolidated balance sheet. During the three months ended September 30, 2023, $10 million of letter of credit was drawn. As of September 30, 2023, there was an aggregate of $11.9 million in letters of credit outstanding. Convertible Notes In August 2020, Legacy Proterra issued $200.0 million aggregate principal amount of Convertible Notes with an initial maturity date on August 4, 2025. The Convertible Notes had a cash interest of 5.0% per annum payable at each quarter end and a paid-in-kind (“PIK”) interest of 4.5% per annum payable by increasing the principal balance at each quarter end. Each of the Convertible Notes rank equally without preference or priority of any kind over one another, but senior in all rights, privileges and preferences to all shares of the Company’s capital stock and all other securities of the Company that are convertible into or exercisable for the Company’s capital stock directly or indirectly. The Convertible Notes are secured by substantially all of the assets of Legacy Proterra, including its intellectual property. Prior to the maturity date, in the event of a liquidation or sale of the Company, the Company was required to pay to the holders of Convertible Notes the greater of (i) 150% of the principal balance of the Convertible Notes or (ii) the consideration that the holders would have received had the holders elected to convert the Convertible Notes into common stock immediately prior to such liquidation event. The Convertible Notes do not entitle the holders to any voting rights or other rights as a stockholder of the Company, unless and until the Convertible Notes are actually converted into shares of the Company’s capital stock in accordance with their terms. The Note Purchase Agreement contains certain customary non-financial covenants. In addition, the Note Purchase Agreement requires the Company to maintain liquidity at quarter end (“Minimum Liquidity Covenant”) of not less than the greater of (i) $75.0 million and (ii) four times of Cash Burn for the three-month period then ended. See below for details regarding modifications to the Minimum Liquidity Covenant. In connection with the issuance of the Convertible Notes, the Company issued warrants to the holders of Convertible Notes to purchase 4.6 million shares of Company capital stock at an exercise price of $0.02 per share. The warrants were freestanding financial instruments and, prior to the closing of the Business Combination (the “Closing”), were classified as a liability due to the possibility that they could become exercisable into Legacy Proterra convertible preferred stock. Upon the consummation of the Merger, the stock issuable upon exercise of the warrants is Proterra common stock, with no possibility to convert to Legacy Proterra convertible preferred stock. As a result, the carrying amount of the warrant liability was reclassified to stockholders’ equity. The warrant liability of $29.0 million was initially measured at fair value on its issuance date and recorded as a debt discount and amortized during the term of the Convertible Notes to interest expense using the effective-interest method. The warrant liability was remeasured on a recurring basis at each reporting period date, with the change in fair value reported in the statement of operations. Upon any exercise of the warrants to common stock, the carrying amount of the warrant liability was reclassified to stockholders’ equity. In the fourth quarter of 2021, all remaining outstanding warrants were exercised. Prior to the Closing, the embedded features of the Convertible Notes were comprised of conversion options that had the economic characteristics of a contingent early redemption feature settled in a variable number of shares of Company stock. These conversion options were bifurcated and accounted for separately from the host debt instrument. The derivative liability of $68.5 million was initially measured at fair value on the issuance date of the Convertible Notes and recorded as debt discount and was amortized during the term of the Convertible Notes to interest expense using the effective-interest method. The derivative liability was remeasured on a recurring basis at each reporting period date, with the change in fair value reported in the statement of operations. Upon the consummation of the Merger, the embedded conversion features associated with the Convertible Notes no longer qualified for derivative accounting since the conversion price became fixed. The carrying amount of the embedded derivative, the fair value as of June 14, 2021 (the “Closing Date”), was reclassified to stockholders’ equity in accordance with Topic 815, Derivatives and Hedging. Issuance costs of $5.1 million were also recorded as debt discount and are amortized during the term of the Convertible Notes to interest expense using the effective interest method. On June 14, 2021, certain Convertible Note holders with an original aggregate principal amount of $46.5 million elected to convert their Convertible Notes at the Closing. An aggregate of $48.8 million principal and interest was reclassified to additional paid-in capital, and $21.0 million of remaining related debt issuance costs were expensed to interest expense. The outstanding Convertible Notes including accrued interest will be automatically converted to common stock at $6.5712 per share pursuant to the mandatory conversion provisions, if and when the volume-weighted average price (“VWAP”) of the common stock exceeds $9.86 over 20 consecutive days subsequent to January 13, 2022. The Company was not in compliance with the Minimum Liquidity Covenant as of December 31, 2022. The Company received a waiver of the Minimum Liquidity Covenant in February 2023 which provided for retroactive effect, so that no such event of default occurred in the year ended December 31, 2022. The Company’s inability to deliver audited financial statements certified by the Company’s independent registered public accounting firm without qualification (or similar notation) as to going concern with respect to the financial statements for the year ended December 31, 2022 would have been an event of default under both the Senior Credit Facility and the Convertible Notes. On March 14, 2023, the Company obtained a limited advance waiver from the holders of the Convertible Notes with respect to the covenant that requires an unqualified statement regarding the Company being able to continue as a going concern until March 31, 2023. On March 31, 2023, the Company received a waiver for the Senior Credit Facility to consent to the delivery of the 2022 Financials with a going concern qualification and waived the cross default of the corresponding covenant under the Convertible Notes in connection with the 2022 Financials. As a result, the Company was in compliance with the covenants contained in the Senior Credit Facility and Convertible Facility as of March 31, 2023. Amendment to the Notes Purchase Agreement and Convertible Notes On March 31, 2023, the Company entered into an amendment to the Notes Purchase Agreement and Convertible Notes, which includes amendments to the interest rate, maturity date, mandatory and optional conversion rights, limitations on the issuance of shares of the Company’s common stock upon conversion and the Company’s obligation to seek stockholder approvals as described below, minimum liquidity requirements and certain other covenants described in further detail below (together, the “Convertible Notes Amendments”). The Convertible Notes Amendments provide for (i) a waiver of the Minimum Liquidity Covenant through May 31, 2024, requiring instead a minimum Liquidity (as defined in the Convertible Notes Amendments) of $125.0 million as of the last day of each quarter from March 31, 2023 through and including May 31, 2024, and (ii) a waiver of the requirement that the Company’s financial statements be certified by the Company’s auditor without qualification (or similar notation) as to going concern for the Company’s consolidated financial statements for fiscal years 2022 and 2023. After May 31, 2024, the Convertible Notes require the Company to maintain Liquidity at each quarter end of not less than the greater of (i) $75.0 million and (ii) four times of Cash Burn (as defined in the Convertible Notes Amendments) for the three-month period then ended. In addition, the Convertible Notes contain an additional holding company covenant limiting the Company’s ability to engage in business, operations and activities other than as set forth in the Convertible Notes. The Convertible Notes Amendments extended the maturity date of the Convertible Notes to August 4, 2028, except with respect to $3.5 million original principal amount, which have since also been extended as described below. The annual interest rate was increased to 12.0% per annum, consisting of 5.0% in cash and 7.0% PIK interest with the PIK default rate proportionally increased to 9.0%. The increased PIK interest on the Convertible Notes is to be accrued from March 17, 2023. In addition, the Convertible Notes Amendments amended the mandatory conversion provision in the existing Convertible Notes to provide for mandatory conversion only on or after March 31, 2024, if the daily VWAP of the Company’s common stock equals or exceeds (a) $15.00 after March 31, 2024 to but not including March 31, 2025, or (b) $12.00 after March 31, 2025, in each case, over a period of 20 consecutive trading days and providing that if the mandatory conversion trigger is met, to convert at a conversion price equal to (i) $4.00 until 1/3 of the aggregate balance of such Convertible Note (including all PIK interest and cash interest accrued but not paid) is converted, (ii) thereafter, $5.00 until 1/3 of the aggregate balance of the such Convertible Note is converted, and (iii) thereafter, $6.00. The conversion prices will be equitably adjusted to reflect any stock dividends, stock splits, reverse stock splits, recapitalizations or other similar events. In addition, following the Convertible Notes Amendments, holders of the Convertible Notes have an additional option, at any time on or after March 31, 2024 until maturity of the Convertible Notes, to convert at a conversion price equal to (i) $4.00 until 1/3 of the aggregate balance of the such Convertible Note is converted, (ii) thereafter, $5.00 until 1/3 of the aggregate balance of the such Convertible Note is converted, and (iii) thereafter, $6.00, which conversion right shall be exercisable in whole or in part from time to time; provided, however, that if the Company consummates a Qualified Financing (as defined below), the holder, at its option, at any time or from time to time on or after March 31, 2024, may convert its Convertible Notes at a conversion price equal to 75% of the lowest per share cash purchase price of the common stock or preferred stock sold by Proterra in any Qualified Financing, subject to a $1.016 floor conversion price. “Qualified Financing” means, as of any date of determination, a bona fide equity financing, if any, on or after March 31, 2023, in which the Company or Proterra OpCo sells equity or equity-linked securities in a capital-raising transaction (which may include a public offering of the Company’s equity securities). Subject to certain exceptions, the Convertible Notes also restrict the Company’s ability to, among other things: dispose of or sell the Company’s assets; make material changes in the Company’s business or management, or accounting and reporting practices; acquire, consolidate, or merge with other entities; incur additional indebtedness; create liens on the Company’s assets; pay dividends; make investments; enter transactions with affiliates; and pre-pay other indebtedness. The Convertible Notes also contain customary events of default, including, among others, the failure to make any payment of principal (or any other payment) when due under the Convertible Notes within five The Convertible Notes provide that no “person” or “group” (within the meaning of Section 13(d) of the Exchange Act) will be entitled to receive any of the Company’s common stock otherwise deliverable upon conversion of the Convertible Notes to the extent that such receipt would cause such person or group to become, directly or indirectly, a “beneficial owner” as defined in Rule 13d-3 under the Exchange Act of more than 40% of the Company’s common stock outstanding at such time (the “Beneficial Ownership Limitation”), and no conversion of the Convertible Notes shall take place to the extent (but only to the extent) that such receipt (or conversion) would cause any Note holder or its affiliates to beneficially own shares of the Company’s common stock in excess of the Beneficial Ownership Limitation. The Convertible Notes also provide for certain limitations on the conversion rights of the holders of the Convertible Notes, including caps on the number of shares of common stock deliverable upon conversion subject to obtaining stockholder approval, as described below. The Company has agreed to use its best efforts to obtain stockholder approval of (i) the issuance of more than 19.99% of the Company’s outstanding common stock in accordance with Nasdaq listing standards (the “Nasdaq Proposal”) and (ii) an amendment to the Company’s certificate of incorporation to increase the number of authorized shares of common stock. Prior to the receipt of stockholder approval of the Nasdaq Proposal, the maximum number of shares of common stock that may be issued upon conversions of the Convertible Notes will be 45,257,360 shares. If stockholder approval of the Nasdaq Proposal is obtained, until and unless the Company receives stockholder approval of an amendment to the Company’s certificate of incorporation to increase the number of authorized shares of the Company’s common stock, the maximum number of shares of common stock that may be issued upon conversions of the Convertible Notes will be 177,782,000 shares. If the Company receives both stockholder approvals, the number of shares of the Company’s common stock that may be issued upon conversion of the Convertible Notes will be limited by the number of authorized and available shares, subject to the Beneficial Ownership Limitation described above. The Company was obligated to use best efforts to seek the above stockholder approvals as promptly as practicable and no later than the Company’s 2023 annual meeting of stockholders; provided that if such stockholder approvals are not received at the Company’s 2023 annual meeting of stockholders, the Company is obligated to call a special meeting of stockholders every 6 months until such stockholder approvals are received. For any additional shares exceeding the 45,257,360 or 177,782,000 share limits set forth above, the Convertible Notes holders had the right to elect either (x) to rescind the conversion with respect to (and only with respect to) the portion of the balance of the Convertible Notes that relates to the number of shares of the Company’s common stock exceeding the applicable limitations (the “Excess Shares”), or (y) for the Company to pay to such Convertible Note holder an amount equal to the product of (A) the number of Excess Shares, multiplied by (B) the simple average of the daily VWAP of the common stock for the 20 consecutive trading days ending on and including the trading day immediately preceding the applicable conversion date. Immediately prior to the Convertible Notes Amendments, the Convertible Notes, net of debt discount and issuance costs, consisted of the following (in thousands): March 31, 2023 December 31, 2022 Principal $ 153,500 $ 153,500 PIK interest 19,196 17,301 Total principal 172,696 170,801 Less debt discount and issuance costs (44,275) (48,109) Total Convertible Notes $ 128,421 $ 122,692 In accordance with ASC Topic No. 470-50, Debt – Modifications and Extinguishments, the Convertible Notes Amendments were determined to be an extinguishment of the existing debt and an issuance of new debt upon the effectiveness of the Convertible Notes Amendments on March 31, 2023 . The new debt is initially recorded at its fair value of $313.4 million, and a loss on debt extinguishment is calculated as the difference between the fair value of the new debt, the net carrying amount of the old debt, and other adjustments required under US GAAP. The Company recorded a loss on debt extinguishment of $177.9 million in the condensed consolidated statements of operations and the $7.2 million fair value of the mandatory conversion feature under the Convertible Notes immediately prior to the Convertible Notes Amendments were recorded to offset stockholders’ equity in accordance with Topic 815, Derivatives and Hedging. The embedded features in the Convertible Notes include conversion options that had the economic characteristics of a contingent early redemption feature settled in a variable number of shares of the Company’s common stock. These conversion features were bifurcated and accounted for as a derivative liability separately from the host debt instrument. As of March 31, 2023, the fair value of derivative liability of $135.7 million was recorded as debt discount on the condensed consolidated balance sheets, which will be amortized during the term of the Convertible Notes to interest expense using the effective-interest method. The derivative liability will be remeasured on a recurring basis at each reporting period date, with the change in fair value reported in the statement of operations. The Convertible Notes Amendments were a non-cash transaction and had no impact to the financing activities in the statements of cash flows for the three and six months ended June 30, 2023. Upon effectiveness of the Convertible Notes Amendments, the Convertible Notes, inclusive of debt premium, consisted of the following (in thousands): March 31, 2023 Principal $ 153,500 PIK interest 19,371 Total principal 172,871 Plus debt premium 4,864 Total Convertible Notes $ 177,735 On May 19, 2023, $3.5 million original principal amount of Convertible Notes was amended to extend the maturity date to August 4, 2028. On June 23, 2023, the stockholders of the Company approved and the Company filed in Delaware an amendment to the Company’s Certificate of Incorporation to increase the total number of authorized shares of common stock from 500,000,000 shares to 1,000,000,000 shares. The stockholders also approved the Nasdaq Proposal. Upon receiving the stockholder approval, certain embedded conversion features associated with the Convertible Notes no longer qualify for derivative accounting. The carrying amount of the derivative liability of $20.8 million associated with those conversion features, which is the fair value as of June 23,2023, was reclassified to stockholders’ equity in accordance with Topic 815, Derivatives and Hedging. The remaining derivative liabilities are continually remeasured on a recurring basis at each reporting period date, with the change in fair value reported in the statement of operations. See Note 3, Fair Value of Financial Instruments, for details of valuation methodology and impact of change of fair value of derivative liability. The Bankruptcy Petitions are considered an event of default under the Convertible Notes, triggering the maturity date of the Convertible Notes. The principal and accrued unpaid interest became due and payable immediately. The Convertible Notes are fully secured and therefore not subject to compromise, and accordingly it is continually accounted under Topic 470, debt. As the embedded conversion features associated with the Convertible Notes expired on maturity date, the change of fair value of $81.3 million was recorded to other income on the consolidated statement of operation. The unamortized debt premium of approximately $4.7 million was written off to interest expense. Pursuant to the final cash collateral order, post-petition interest on pre-petition debt continues to accrue at the non-default rate until the earlier of (i) April 1, 2024 and (ii) the notice period following an event of default, unless an extension is approved by the Bankruptcy Court, and paid when such payment would have been due under the Notes Purchase Agreement. As of September 30, 2023, the Convertible Notes consisted of the following (in thousands): September 30, 2023 Principal $ 153,500 PIK interest 25,492 Total principal $ 178,992 The amortization expense of debt discount (premium) and issuance costs were $(4.7) million and $(1.0) million for the three and nine months ended September 30, 2023, respectively. The amortization expense of debt discount and issuance costs were $3.6 million and $10.4 million for the three and nine months ended September 30, 2022, respectively.

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	Leases As a Lessor The net investment in leases were as follows (in thousands): September 30, 2023 December 31, 2022 Net investment in leases, current $ 1,078 $ 985 Net investment in leases, non-current 9,771 9,304 Total net investment in leases $ 10,849 $ 10,289 Interest income from accretion of net investment in lease was not material in the nine months ended September 30, 2023 or 2022. Future minimum payments receivable from operating and sales-type leases as of September 30, 2023 for each of the next five years were as follows: Operating leases Sales-type leases Remainder of 2023 $ 70 $ 229 2024 — 1,010 2025 — 1,762 2026 — 1,808 2027 — 1,808 Thereafter — 4,896 Total minimum lease payments $ 70 $ 11,513 As a Lessee The Company leases its office and manufacturing related facilities in Burlingame and City of Industry, California, Greenville and Greer, South Carolina, and Rochester Hills, Michigan under operating lease agreements with various expiration dates from 2023 through 2033. The Company had no material finance leases as of September 30, 2023. Maturities of operating lease liabilities as of September 30, 2023 were as follows (in thousands): Remainder of 2023 $ 1,725 2024 4,204 2025 3,487 2026 2,615 2027 2,238 Thereafter 9,858 Total undiscounted lease payment 24,127 Less: imputed interest (4,637) Total operating lease liabilities $ 19,490 Operating lease expense was $2.0 million and $6.0 million for the three and nine months ended September 30, 2023, respectively. Operating lease expense was $1.9 million and $5.4 million for the three and nine months ended September 30, 2022, respectively. Short-term and variable lease expenses for the nine months ended September 30, 2023 and 2022 were not material. Supplemental cash flow information related to leases were as follows (in thousands): Nine Months Ended September 30, 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ (6,295) $ (4,822) Lease liabilities arising from obtaining right-of-use assets: Operating lease $ — $ 4,178 Finance lease $ 699 $ — Operating lease right-of-use assets and liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Operating leases Operating lease right-of-use assets $ 15,326 $ 20,274 Operating lease liabilities, current — 6,876 Operating lease liabilities, non-current — 18,098 Total operating lease liabilities $ — $ 24,974 The operating lease right-of-use liabilities, which is included in the liabilities subject to compromise, was $19.5 million. The weighted average remaining lease term and discount rate of operating leases were 6.7 years and 6.1%, respectively, as of September 30, 2023. The weighted average remaining lease term and discount rate of operating leases were 6.4 years and 6.2%, respectively, as of December 31, 2022. As of September 30, 2023, the Company had no significant additional operating leases and finance leases that have not yet commenced.
Leases	Leases As a Lessor The net investment in leases were as follows (in thousands): September 30, 2023 December 31, 2022 Net investment in leases, current $ 1,078 $ 985 Net investment in leases, non-current 9,771 9,304 Total net investment in leases $ 10,849 $ 10,289 Interest income from accretion of net investment in lease was not material in the nine months ended September 30, 2023 or 2022. Future minimum payments receivable from operating and sales-type leases as of September 30, 2023 for each of the next five years were as follows: Operating leases Sales-type leases Remainder of 2023 $ 70 $ 229 2024 — 1,010 2025 — 1,762 2026 — 1,808 2027 — 1,808 Thereafter — 4,896 Total minimum lease payments $ 70 $ 11,513 As a Lessee The Company leases its office and manufacturing related facilities in Burlingame and City of Industry, California, Greenville and Greer, South Carolina, and Rochester Hills, Michigan under operating lease agreements with various expiration dates from 2023 through 2033. The Company had no material finance leases as of September 30, 2023. Maturities of operating lease liabilities as of September 30, 2023 were as follows (in thousands): Remainder of 2023 $ 1,725 2024 4,204 2025 3,487 2026 2,615 2027 2,238 Thereafter 9,858 Total undiscounted lease payment 24,127 Less: imputed interest (4,637) Total operating lease liabilities $ 19,490 Operating lease expense was $2.0 million and $6.0 million for the three and nine months ended September 30, 2023, respectively. Operating lease expense was $1.9 million and $5.4 million for the three and nine months ended September 30, 2022, respectively. Short-term and variable lease expenses for the nine months ended September 30, 2023 and 2022 were not material. Supplemental cash flow information related to leases were as follows (in thousands): Nine Months Ended September 30, 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ (6,295) $ (4,822) Lease liabilities arising from obtaining right-of-use assets: Operating lease $ — $ 4,178 Finance lease $ 699 $ — Operating lease right-of-use assets and liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Operating leases Operating lease right-of-use assets $ 15,326 $ 20,274 Operating lease liabilities, current — 6,876 Operating lease liabilities, non-current — 18,098 Total operating lease liabilities $ — $ 24,974 The operating lease right-of-use liabilities, which is included in the liabilities subject to compromise, was $19.5 million. The weighted average remaining lease term and discount rate of operating leases were 6.7 years and 6.1%, respectively, as of September 30, 2023. The weighted average remaining lease term and discount rate of operating leases were 6.4 years and 6.2%, respectively, as of December 31, 2022. As of September 30, 2023, the Company had no significant additional operating leases and finance leases that have not yet commenced.
Leases	Leases As a Lessor The net investment in leases were as follows (in thousands): September 30, 2023 December 31, 2022 Net investment in leases, current $ 1,078 $ 985 Net investment in leases, non-current 9,771 9,304 Total net investment in leases $ 10,849 $ 10,289 Interest income from accretion of net investment in lease was not material in the nine months ended September 30, 2023 or 2022. Future minimum payments receivable from operating and sales-type leases as of September 30, 2023 for each of the next five years were as follows: Operating leases Sales-type leases Remainder of 2023 $ 70 $ 229 2024 — 1,010 2025 — 1,762 2026 — 1,808 2027 — 1,808 Thereafter — 4,896 Total minimum lease payments $ 70 $ 11,513 As a Lessee The Company leases its office and manufacturing related facilities in Burlingame and City of Industry, California, Greenville and Greer, South Carolina, and Rochester Hills, Michigan under operating lease agreements with various expiration dates from 2023 through 2033. The Company had no material finance leases as of September 30, 2023. Maturities of operating lease liabilities as of September 30, 2023 were as follows (in thousands): Remainder of 2023 $ 1,725 2024 4,204 2025 3,487 2026 2,615 2027 2,238 Thereafter 9,858 Total undiscounted lease payment 24,127 Less: imputed interest (4,637) Total operating lease liabilities $ 19,490 Operating lease expense was $2.0 million and $6.0 million for the three and nine months ended September 30, 2023, respectively. Operating lease expense was $1.9 million and $5.4 million for the three and nine months ended September 30, 2022, respectively. Short-term and variable lease expenses for the nine months ended September 30, 2023 and 2022 were not material. Supplemental cash flow information related to leases were as follows (in thousands): Nine Months Ended September 30, 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ (6,295) $ (4,822) Lease liabilities arising from obtaining right-of-use assets: Operating lease $ — $ 4,178 Finance lease $ 699 $ — Operating lease right-of-use assets and liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Operating leases Operating lease right-of-use assets $ 15,326 $ 20,274 Operating lease liabilities, current — 6,876 Operating lease liabilities, non-current — 18,098 Total operating lease liabilities $ — $ 24,974 The operating lease right-of-use liabilities, which is included in the liabilities subject to compromise, was $19.5 million. The weighted average remaining lease term and discount rate of operating leases were 6.7 years and 6.1%, respectively, as of September 30, 2023. The weighted average remaining lease term and discount rate of operating leases were 6.4 years and 6.2%, respectively, as of December 31, 2022. As of September 30, 2023, the Company had no significant additional operating leases and finance leases that have not yet commenced.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Purchase Commitments As of September 30, 2023, the Company had outstanding inventory and other purchase commitments of $1.9 billion, excluding inestimable variable components. Most of the commitments relate to the expected purchase of 2170 battery cells to be manufactured at a yet to be built LG Energy Solution battery cell plant in the United States, pursuant to a long-term supply agreement. The terms of the agreement require the Company to make certain prepayments that vary in size based on milestones relating to the construction of the US facility. As of September 30, 2023, the Company has made a $10.0 million prepayment, which was recorded as the long-term inventory prepayment on the consolidated balance sheets. See Note 12, Subsequent events, for details related to the announcement of LG Energy Solution related to this US facility. Letters of Credit As of September 30, 2023, the Company had cash collateralized letters of credit outstanding totaling $12.0 million, which will expire over various dates in 2023 and 2024. Legal Proceedings The Company accrues contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. From time to time in the normal course of business, various claims and litigation have been asserted or commenced. Due to uncertainties inherent in litigation and other claims, the Company can give no assurance that it will prevail in any such matters, which could subject the Company to

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity On June 23, 2023, the stockholders of the Company approved and the Company filed in Delaware an amendment to the Company’s Certificate of Incorporation to increase the total number of authorized shares of common stock from 500,000,000 shares to 1,000,000,000 shares. As of September 30, 2023, the Company is authorized to issue 1,010,000,000 shares of capital stock, with a par value of $0.0001 per share. The authorized shares consist of 1,000,000,000 shares of common stock and 10,000,000 shares of preferred stock. As of September 30, 2023, 228,167,279 shares of common stock were issued and outstanding, and no shares of preferred stock were issued and outstanding. The holders of each share of common stock are entitled to one vote per share. As of September 30, 2023, the Company had reserved shares of common stock for issuance as follows (in thousands): 2010 Equity Incentive Plan 10,317 2021 Equity Incentive Plan 34,537 2021 Employee Stock Purchase Plan 4,877 Warrants 1 Earnout Stock 18,009 Convertible notes 247,835 Total 315,576

Equity Plans and Stock-based Co

Equity Plans and Stock-based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Equity Plans and Stock-based Compensation	Equity Plans and Stock-based Compensation 2010 Equity Incentive Plan In 2010, Legacy Proterra adopted the 2010 Equity Incentive Plan (the “2010 Plan”), which provided for the grant of stock options, stock appreciation rights, restricted stock, and restricted stock units. Upon Closing, the then outstanding options under the 2010 Plan were converted into options exercisable to purchase an aggregate of 22,532,619 shares of common stock. Following the Closing, such options continue to be subject to the terms of the 2010 Plan and applicable award agreements; however, no further awards can be granted under the 2010 Plan. As of September 30, 2023, options to purchase 10,316,698 shares of common stock remained outstanding under the 2010 Plan. 2021 Equity Incentive Plan The 2021 Plan was adopted by the ArcLight Board prior to the Closing, approved by ArcLight’s shareholders on June 11, 2021, and became effective upon the Closing Date. The Equity Incentive Plan allows the Company to grant awards of stock options, restricted stock awards, stock appreciation rights, restricted stock units (“RSUs”), performance awards, and stock bonus awards to officers, employees, directors and consultants. The Company initially reserved 10,000,000 shares of common stock, plus 387,531 reserved shares not issued under the 2010 Plan on the effective date of the 2021 Plan. The number of shares reserved for issuance under the 2021 Plan increases automatically on January 1 of each of 2022 through 2031 by the number of shares equal to the lesser of 4% of the total number of outstanding shares of all classes of common stock as of the immediately preceding December 31, or a number as may be determined by the Board. In the first quarter of 2022 and 2023, the shares of common stock reserved for issuance were increased by 8,878,388 and 9,050,606, respectively, pursuant to the 2021 Plan. The exercise price of stock options granted must be at least equal to the fair market value of common stock on the date of grant. Incentive stock options granted to an individual who holds, directly or by attribution, more than ten percent of the total combined voting power of all classes of capital stock must have an exercise price of at least 110% of the fair market value of common stock on the date of grant. Subject to certain adjustments, no more than 30,000,000 shares may be issued pursuant to the exercise of incentive stock options granted under the 2021 Plan. The maximum term of options granted is ten years from the date of grant, except that the maximum permitted term of incentive stock options granted to an individual who holds, directly or by attribution, more than ten percent of the total combined voting power of all classes of capital stock is five years from the date of grant. Stock option and RSU awards generally vest annually over a four-year period. In connection with the Company’s bankruptcy filing on August 7, 2023, the Company is not authorized to grant any additional awards under the Equity Incentive Plan. 2021 Employee Stock Purchase Plan Proterra’s 2021 Employee Stock Purchase Plan (the “ESPP”), including the authorization of the initial share reserve thereunder, was adopted by the ArcLight Board prior to the Closing, approved by ArcLight’s shareholders on June 11, 2021, and became effective upon the Closing Date. An aggregate of 1,630,000 shares of common stock were reserved and available for sale under the ESPP. The aggregate number of shares reserved for sale under the ESPP increases automatically on January 1 of each of 2022 through 2031 by a number of shares equal to the lesser of 1% of the total number of outstanding shares of common stock as of the immediately preceding December 31 or a number of shares as may be determined by the Board or the compensation committee. The aggregate number of shares issued over the term of the ESPP, subject to certain adjustments, may not exceed 16,300,000 shares. In the first quarter of 2022 and 2023, the shares of common stock reserved for issuance were increased by 2,219,597 and 2,262,651, respectively, pursuant to the ESPP. The ESPP allows eligible employees to purchase shares of common stock at a discount through payroll deductions of up to 15% of their eligible compensation, at not less than 85% of the fair market value, as defined in the ESPP, subject to any plan limitations. A participant may purchase a maximum of 2,500 shares during each 6-month offering period and $25,000 in any one calendar year. The offering periods generally start on the first trading day on or after November 15th and May 15th of each year. The first offering period started in the fourth quarter of 2021. The Company calculated the fair value of the employees’ purchase rights related to the ESPP using the Black-Scholes model. In August 2023, in connection with the Company’s bankruptcy filing, all outstanding offering periods under the ESPP program were discontinued, and the Company recorded the remaining unrecognized stock-based compensation expense in the three months ended September 30, 2023. The stock-based compensation expense were approximately $0.8 million and $1.0 million for the nine months ended September 30, 2023 and 2022, respectively. In the nine months ended September 30, 2023 and 2022, the Company issued 586,008 and 325,106 shares of common stock under the ESPP with a purchase price of $1.13 and $4.62 per share, respectively. A summary of the Company’s stock option activity and related information was as follows: Options Outstanding Number of Stock Options Outstanding Weighted- Average Exercise Price Weighted-Average Remaining Contractual Life Aggregate Intrinsic Value Balance as of December 31, 2022 (1) 14,256,697 $ 4.32 5.5 $ 9,469 Granted 3,035,164 1.41 Exercised (57,036) 1.98 Cancelled/forfeited/expired (2) (3,250,706) 5.06 Balance as of September 30, 2023 13,984,119 $ 3.53 5.2 $ — Exercisable as of September 30, 2023 9,844,575 $ 3.80 3.5 $ — __________________ (1) Excluding Equity Awards of 2,677,500 shares and Milestone Options of 669,375 shares. See below for further details. (2) Excluding 2,677,500 shares cancelled under the Equity Awards with weighted average exercise price of $19.61 per share, and 669,375 shares cancelled under the Milestone Options with exercise price of $5.33 per share. In March 2020, in conjunction with Mr. Allen’s appointment as the then President and Chief Executive Officer, the board of directors of Legacy Proterra approved a grant to Mr. Allen of stock option awards with respect to 4,685,624 shares, comprised of (1) 1,338,749 shares of a time-based award with an exercise price of $5.33 per share vesting quarterly over four years, (2) 2,677,500 shares of a time-based award consisting of four tranches with an exercise price of $11.21, $16.81, $22.41 and $28.02 per share, respectively, and vesting quarterly over four years (“Equity Awards”), and (3) 669,375 shares of milestone-based award with an exercise price of $5.33 per share vesting entirely and becoming exercisable on the first trading day following the expiration of the lockup period of the Company’s initial public offering or the consummation of a change in control of the Company or upon the consummation of a merger involving a special purpose acquisition company (“Milestone Options”). The stock-based compensation expense for Milestone Options was recognized at the time the performance milestone became probable of achievement, which was at the time of Closing. Upon Closing, the 669,375 shares underlying the Milestone Options fully vested, and $2.1 million stock-based compensation expense was recognized in June 2021. As of June 30, 2023, Mr. Allen retired from the board, and his unvested shares were canceled. Aggregate intrinsic value represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money stock options. The total intrinsic value of stock options exercised was $0.1 million for the nine months ended September 30, 2023. The total estimated grant date fair value of stock options vested was $5.0 million for the nine months ended September 30, 2023. As of September 30, 2023, the total unrecognized stock-based compensation expense related to outstanding stock options was $6.9 million, which is expected to be recognized over a weighted-average period of 3.0 years. The fair value of stock options granted is estimated on the date of grant using the following assumptions: Nine Months Ended September 30, 2023 2022 Expected term (in years) 6.3 6.3 Risk-free interest rate 3.7 % 2.0 % Expected volatility 67.2 % 55.1 % Expected dividend rate — — Restricted Stock Units A summary of the Company's RSU activity and related information is as follows: Number of RSUs Weighted Average Grant Date Fair Value Balance as of December 31, 2022 5,733,227 $ 7.07 Granted 5,154,438 1.60 Released (1,402,679) 6.77 Forfeited (2,079,799) 5.29 Balance as of September 30, 2023 7,405,187 $ 3.82 The compensation expense related to the service-based RSU awards is determined using the fair market value of the Company’s common stock on the date of the grant. As of September 30, 2023, the total unrecognized stock-based compensation expense related to outstanding RSUs was $24.0 million, which is expected to be recognized over a weighted-average period of 3.0 years. Stock-based Compensation Expense Stock-based compensation expense included in operating results was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Cost of goods sold $ 209 $ 456 $ 786 $ 1,350 Research and development 1,250 1,409 3,707 3,690 Selling, general and administrative 3,023 3,491 8,708 11,273 Total stock-based compensation expense $ 4,482 $ 5,356 $ 13,201 $ 16,313

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, less the weighted-average unvested common stock subject to repurchase or forfeiture as they are not deemed to be issued for accounting purposes. Diluted net loss per share is computed by giving effect to all potential shares of common stock, including stock options, RSUs and warrants, to the extent they are dilutive. The computation of basic and diluted net loss per share of common stock attributable to common stockholders was as follows (in thousands, except for per share data): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Numerator: Net income (loss) $ 5,216 $ (65,061) $ (269,755) $ (156,960) Effect of dilutive securities: Interest expense to be recognized upon conversion of Convertible Notes (1) — (47,891) — (40,154) Numerator for diluted EPS - Net loss after the effect of dilutive securities $ 5,216 $ (112,952) $ (269,755) $ (197,114) Denominator: Weighted-average shares used in computing net loss per share of common stock, basic 227,869 225,291 227,192 223,782 Convertible Notes (1) — 25,413 — 24,855 Diluted weighted average shares 227,869 250,704 227,192 248,637 Net income (loss) per share of common stock: Basic $ 0.02 $ (0.29) $ (1.19) $ (0.70) Diluted $ 0.02 $ (0.45) $ (1.19) $ (0.79) __________________ (1) Adjustment is under the “if-converted” method. Adjustments for the three months ended September 30, 2022 include write-off of $59.0 million unamortized debt discount of the Convertible Notes as of June 30, 2022, offset by the $7.4 million interest expense recorded in net loss of three months ended September 30, 2022. Adjustments for the nine months ended September 30, 2022 include write-off of $62.3 million unamortized debt discount of the Convertible Notes as of December 31, 2021, offset by the $14.5 million interest expense recorded in net loss of nine months ended September 30, 2022. The Company applies the treasury stock method when calculating the diluted net income (loss) per share of common stock and “if-converted” method for Convertible Notes when applicable. Prior to the Convertible Notes Amendments, the outstanding Convertible Notes including accrued interest would have been automatically converted to common stock at $6.5712 per share pursuant to the mandatory conversion provisions, if and when the VWAP exceeded $9.86 over 20 consecutive days subsequent to January 13, 2022. Following the Convertible Notes Amendments, the conditions for the convertible features under the Convertible Notes were not satisfied. See Note 5, Debt, for additional information on the conversion provisions of the Convertible Notes. The voluntary petition filing on August 7, 2023 is considered an event of default under the Convertible Notes, triggering the maturity date of the Convertible Notes. The conversion features under the Convertible Notes expired on the maturity date. No adjustment is required to the weighted-average shares used in computing the diluted net income (loss) per share for the three and nine months ended September 30, 2023. The potentially dilutive securities were as follows (in thousands): September 30, 2023 Stock options and RSUs to purchase common stock 21,389 Warrants to purchase common stock 1 Total 21,390

401(k) Plan

401(k) Plan	9 Months Ended
	Sep. 30, 2023
Retirement Benefits [Abstract]
401(k) Plan	401(k) Plan The Company sponsors a 401(k) defined contribution plan covering all eligible employees and provides a matching contribution for the first 4% of their salaries. The matching contribution costs incurred were $0.9 million and $2.9 million in the three and nine months ended September 30, 2023, respectively. The matching contribution costs incurred were $0.9 million and $2.4 million in the three and nine months ended September 30, 2022, respectively.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Key Employee Incentive Plan On October 10, 2023, the Bankruptcy Court approved a Key Employee Incentive Plan (the “KEIP”), which had previously been approved by the Compensation Committee, subject to Bankruptcy Court approval. The KEIP was developed with the assistance of advisors to provide incentive-based cash compensation to its participants based on creating business value and executing one or more of any potential transaction involving the Company (including through a merger, recapitalization or sale of substantially all of the assets of the Company) or any sale, disposition or winding down of any business unit, business division or asset of the Company (each, a “Transaction”). Each participant of the KEIP (the “KEIP Participants”) will be eligible to receive a KEIP award that represents the potential to earn one or more cash payments (each, a “KEIP Payment”), which will be in lieu of any existing incentive and retention opportunities, including the Company’s short-term cash bonus, equity incentive and retention programs. Generally, KEIP Payments must be earned pursuant to the terms provided under the KEIP in order to be payable to KEIP Participants. The timing of KEIP Payments are subject to the terms provided under the KEIP. KEIP Participants may earn an aggregate amount of approximately $1.4 million upon approval by the Bankruptcy Court of a Transaction which, along or in combination with a series of prior Transactions, meet a certain numerical threshold. KEIP Participants may earn an additional KEIP Payment equal to 3% of the excess value above such certain numerical threshold associated with such Transaction. If the series of Transactions do not meet the relevant threshold amounts, there will be no payouts under the KEIP. The KEIP is subject to further conditions regarding continued employment of the KEIP participants and other conditions. Post-Petition Key Employee Retention Plan On October 5, 2023, the Bankruptcy Court approved a Key Employee Retention Plan (the “KERP”), which had previously been approved by the Compensation Committee, subject to Bankruptcy Court approval. The KERP provides for grants of retention awards that are subject to clawback if the KERP participant is terminated for cause or voluntarily resigns before the earlier of either the six-month anniversary or one-year anniversary of the date of grant as applicable, or a Transaction involving the Company or the business unit or division for which the KERP participant provides substantially all of his or her services to. Payments pursuant to the KERP will not exceed, in the aggregate, approximately $1.5 million. Volta Truck Bankruptcy On October 17, 2023, Volta Trucks, a Proterra Powered customer, announced that it will file for administration in the United Kingdom and insolvency proceedings in other relevant jurisdictions. The Company recorded a $1.6 million impairment charge in the three months ended September 30, 2023 to write off its long-term investments in this entity. As the Company has sufficient deferred revenue from prepayments outstanding, no credit losses over its accounts receivables outstanding as of September 30, 2023 are expected. LG US Facility Plan Modification

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and the rules and regulations of the SEC. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2022 and the related notes incorporated by reference in the Company’s Annual Report (the “Annual Report”) on Form 10-K, filed with SEC on March 17, 2023 and amended on May 1, 2023, which provides a more complete discussion of the Company’s accounting policies and certain other information. The information as of December 31, 2022 was derived from the Company’s audited financial statements. The condensed consolidated financial statements were prepared on the same basis as the audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for a fair presentation of the Company’s financial position as of September 30, 2023 and the results of operations and cash flows for the nine months ended September 30, 2023 and 2022. The results of operations for the nine months ended September 30, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023.
Use of Estimates	Use of Estimates In preparing the condensed consolidated financial statements and related disclosures in conformity with U.S. GAAP and pursuant to the rules and regulations of the SEC, the Company must make estimates and judgments that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results may differ materially from these estimates.
Segments	SegmentsThe Company operates in the United States and has sales to the European Union, Canada, United Kingdom, Australia, Japan and Türkiye.The Company’s chief operating decision maker is its Chief Executive Officer (CEO) who reviews financial information presented on a consolidated basis for purposes of making decision on allocating resources and assessing financial performance. Accordingly, the Company has determined that it has a single reportable segment.
Accounts Receivable and Allowance for Credit Losses	Accounts Receivable and Allowance for Credit LossesAccounts receivable are recorded at the invoiced amount and do not bear interest. The Company determines the allowance for credit losses based on historical write-off experience, an analysis of the aging of outstanding receivables, customer payment patterns and expectations of changes in macroeconomic conditions that may affect the collectability of outstanding receivables. The allowance for credit losses was not material as of September 30, 2023 and December 31, 2022.
Credit Risk and Concentration	Credit Risk and Concentration The Company’s financial instruments that are potentially subject to concentrations of credit risk consist primarily of cash, cash equivalents, restricted cash, short-term investments, and accounts receivable. Cash and cash equivalents and short-term investments are maintained primarily at one financial institution as of September 30, 2023 and December 31, 2022, and deposits exceed federally insured limits. Risks associated with cash and cash equivalents, and short-term investments are mitigated by banking with creditworthy financial institutions. The Company has not experienced any losses on its deposits of cash and cash equivalents or its short-term investments. Cash equivalents and short-term investments consist of short-term money market funds, corporate debt securities, and debt securities issued by the U.S. Treasury, which are deposited with reputable financial institutions. The Company’s cash management and investment policy limits investment instruments to securities with short-term credit ratings at the timing of purchase of P-2 and A-2 or better from Moody’s Investors Service and Standard & Poor’s Financial Services, LLC, respectively, with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations. Accounts receivable are typically unsecured and are generally derived from revenue earned from transit agencies, universities and airports in North America and global commercial vehicle manufacturers in North America, the European Union, the United Kingdom, Australia, Japan and Türkiye. The Company periodically evaluates the collectability of its accounts receivable and provides an allowance for potential credit losses as necessary. Given the large order value for customers and the relatively low number of customers, revenue and accounts receivable have typically been concentrated with a limited number of customers. Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, December 31, 2023 2022 2023 2022 2023 2022 Number of customers accounted for 10% or more 3 2 1 2 3 2 Total % of customers accounted for 10% or more 62% 40% 24% 27% 52% 48% Single source suppliers provide the Company with a number of components that are required for manufacturing of its current products. Although there may be multiple suppliers available, many of the components that the Company’s manufacturing process requires are purchased from one single source. If these single source suppliers fail to meet the Company’s requirements on a timely basis at competitive prices or are unable to provide components for any reason, the Company could suffer manufacturing delays, a possible loss of revenue, or incur higher cost of sales, any of which could adversely impact the Company’s operating results. As part of the Chapter 11 proceedings, the Company rejected the existing contract with TPI Composites, Inc., the single source supplier for bus bodies, and the Company may be unable to negotiate another agreement on better terms. As of September 30, 2023, the Company has sufficient bus bodies in inventory to meet its near term production plan.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates the recoverability of property, plant, and equipment and right-of-use assets for possible impairment whenever events or circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of these assets is measured by a comparison of the carrying amounts to the future undiscounted cash flows the assets are expected to generate. If such review indicates that the carrying amount of long-lived assets is not recoverable, the carrying amount of such assets is reduced to fair value. In addition to the recoverability assessment, the Company periodically reviews the remaining estimated useful lives of property, plant, and equipment. If the estimated useful life assumption for any asset is reduced, the remaining net book value is depreciated over the revised estimated useful life.
Deferred Revenue and Revenue Recognition	Deferred Revenue Deferred revenue consists of billings or payments received in advance of revenue recognition that are recognized as revenue once the revenue recognition criteria are met. In some instances, progress billings are issued upon meeting certain milestones stated in the contracts. Accordingly, the deferred revenue balance does not represent the total contract value of non-cancelable arrangements. Invoices are typically due within 30 to 40 days. The current portion of deferred revenue represents the amount that is expected to be recognized as revenue within one year from the balance sheet date. Revenue Recognition The Company derives revenue primarily from the sale of vehicles and charging systems, the installation of charging systems, the sale of battery systems and powertrain components to other vehicle manufacturers, as well as the sale of spare parts and other services provided to customers. Product revenue consists of revenue earned from vehicles and charging systems, battery systems and powertrain components, installation of charging systems, and revenue from leased vehicles, charging systems, and batteries under operating leases. Parts and other service revenue includes revenue earned from spare parts, the design and development of battery systems and powertrain systems for other vehicle manufacturers, and extended warranties. The Company recognizes revenue when or as it satisfies a performance obligation by transferring control of a product or service to a customer. Revenue from product sales is recognized when control of the underlying performance obligations is transferred to the customer. Revenue from sales of vehicles is typically recognized upon delivery when the Company can objectively demonstrate that the criteria specified in the contractual acceptance provisions are achieved prior to delivery. In cases, where the Company cannot objectively demonstrate that the criteria specified in the contractual acceptance provisions have been achieved prior delivery, revenue is recognized upon acceptance by the customer. Revenue from sales of charging systems is recognized at a point in time, generally upon delivery or commissioning when control of the underlying performance obligations are transferred to the customer. Under certain contract arrangements, the control of the performance obligations related to the charging systems is transferred over time, and the associated revenue is recognized over the installation period using an input measure based on costs incurred to date relative to total estimated costs to completion. Spare parts revenue is recognized upon shipment. Extended warranty revenue is recognized over the life of the extended warranty using the time elapsed method. Development service contracts typically include the delivery of prototype products to customers. The performance obligation associated with the development of prototype products as well as battery systems and powertrain components to other vehicle manufacturers, is satisfied at a point in time, typically upon shipping. Revenue derived from performance obligations satisfied over time from charging systems and installation was $0.9 million and $3.7 million for the three months ended September 30, 2023 and 2022, respectively, and $3.7 million and $5.8 million for the nine months ended September 30, 2023 and 2022, respectively. Leasing revenue and extended warranty revenue recognized over time was immaterial for the three and nine months ended September 30, 2023 and 2022, respectively. As of September 30, 2023 and December 31, 2022, the contract assets balance was $3.2 million and $26.1 million, respectively, and these balances are recorded in the prepaid expenses and other current assets on the consolidated balance sheets. The contract assets are expected to be billed within the next twelve months. As of September 30, 2023, the amount of remaining performance obligations that have not been recognized as revenue was $417.4 million. As the Company is in the process of a Bankruptcy Court-approved bidding process that may result in the sale of all or substantially all of its assets during the Chapter 11 Cases, the timing of satisfaction of these performance obligations is not estimable as of September 30, 2023. This amount excludes the value of remaining performance obligations for contracts with an original expected length of one year or less. Our business has the following commercial offerings each addressing a critical component of commercial vehicle electrification. • Proterra Transit designs, develops, manufactures, and sells electric transit buses as an original equipment manufacturer (“OEM”) for North American public transit agencies, airports, universities, and other commercial transit fleets. • Proterra Powered & Energy
Liabilities Subject to Compromise	Liabilities Subject to Compromise Since filing the Chapter 11 petitions, the Company has operated as debtor-in-possession under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code. The liabilities subject to compromise balance is reflective of expected allowed claim amounts in accordance with ASC 852 and are subject to change materially based on the proceedings and continued consideration of claims that may be modified, allowed, or disallowed. Refer to Note 2, Chapter 11 Filing and Other Related Matters, for details.
Product Warranties	Product WarrantiesWarranty expense is recorded as a component of cost of goods sold.
Adopted Accounting Guidance and Accounting Pronouncements Not Yet Effective	Adopted Accounting Guidance and Accounting Pronouncements Not Yet Effective There have been no recent accounting pronouncements, changes in accounting pronouncements or recently adopted accounting guidance during the nine months ended September 30, 2023 that are of significance or potential significance to the Company.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Revenue Disaggregated by Geography	Revenue disaggregated by geography, based on the addresses of the Company’s customers, consists of the following (in Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 United States $ 68,480 $ 82,040 $ 201,585 $ 195,680 Rest of World 17,668 14,183 49,806 33,688 $ 86,148 $ 96,223 $ 251,391 $ 229,368
Concentration of Customer Risk	Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, December 31, 2023 2022 2023 2022 2023 2022 Number of customers accounted for 10% or more 3 2 1 2 3 2 Total % of customers accounted for 10% or more 62% 40% 24% 27% 52% 48%
Deferred Revenue	The changes in deferred revenue inclusive of the balance recorded in the liabilities subject to compromise, consisted of the following (in thousands): Deferred revenue as of December 31, 2022 $ 67,398 Revenue recognized from beginning balance during the nine months ended September 30, 2023 (17,336) Deferred revenue added during the nine months ended September 30, 2023 33,756 Deferred revenue as of September 30, 2023 $ 83,818
Revenue of Commercial Offerings	Revenue of these commercial offerings are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Proterra Transit $ 25,770 $ 56,363 $ 91,745 $ 142,563 Proterra Powered & Energy 60,378 39,860 159,646 86,805 Total $ 86,148 $ 96,223 $ 251,391 $ 229,368
Accrued Warranty Activity	Activity of the accrued warranty inclusive of the balances in the liabilities subject to compromise, consisted of the following (in thousands): Nine Months Ended September 30, 2023 Warranty reserve- beginning of period $ 25,513 Warranty costs incurred (2,991) Net changes in liability for pre-existing warranties, including expirations (3,000) Provision for warranty 13,501 Warranty reserve- end of period $ 33,023

Chapter 11 Filing and Other R_2

Chapter 11 Filing and Other Related Matters (Tables)	9 Months Ended
	Sep. 30, 2023
Reorganizations [Abstract]
Schedule of Reorganization Items	Reorganization items, net incurred as a result of the Chapter 11 Cases presented separately in the accompanying Consolidated Statements of Operations were as follows (in thousands): Three Months Ended September 30, 2023 Nine Months Ended September 30, 2023 Professional fees and other bankruptcy related costs $ 17,530 $ 17,530 Write-off of liabilities subject to compromise (1,139) (1,139) Reorganization items, net $ 16,391 $ 16,391
Schedule of Liabilities Subject to Compromise	Liabilities subject to compromise consisted of the following (in thousands): September 30, 2023 Accounts payable $ 73,947 Accrued liabilities 14,885 Deferred revenue 83,045 Operating lease liabilities 19,490 Other liabilities 22,378 Liabilities subject to compromise $ 213,745

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and liabilities measured at fair value on a recurring basis using the above input categories were as follows (in thousands): Pricing Category Fair Value at September 30, 2023 December 31, 2022 Assets: Cash equivalents and marketable securities: Money market funds Level 1 $ 9 $ 14,941 Short-term investments: U.S. Treasury securities Level 1 17,899 224,359 Total $ 17,908 $ 239,300
Summary of Cash Equivalents and Marketable Securities	The following is a summary of cash equivalents and marketable securities as of September 30, 2023 (in thousands): Amortized Cost Unrealized Loss Estimated Fair Value Cash equivalents: Money market funds $ 9 $ — $ 9 Short-term investments: U.S. Treasury securities 17,905 (6) 17,899 Total $ 17,914 $ (6) $ 17,908 The following is a summary of cash equivalents and marketable securities as of December 31, 2022 (in thousands): Amortized Cost Unrealized Loss Estimated Fair Value Cash equivalents: Money market funds $ 14,941 $ — $ 14,941 Short-term investments: U.S. Treasury securities 224,904 (545) 224,359 Total $ 239,845 $ (545) $ 239,300
Derivative Liability	A summary of the changes of the derivative liability is as follows (in thousands): Derivative liability Fair value at issuance as of March 31, 2023 $ 135,678 Change in fair value (114,878) Reclassification of liability upon charter amendment (20,800) Fair value as of September 30, 2023 $ —

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): September 30, 2023 December 31, 2022 Cash $ 112,805 $ 58,754 Cash equivalents 9 14,941 Total cash and cash equivalents $ 112,814 $ 73,695 The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets to the total of such amounts shown on the statements of cash flows. The restricted cash is primarily collateral for performance bonds issued to certain customers. The collateral is provided in the form of a cash deposit to either support the bond directly or to collateralize a letter of credit that supports the performance bonds. September 30, 2023 December 31, 2022 Cash and cash equivalents $ 112,814 $ 73,695 Restricted cash, current portion 25,546 12,565 Total cash and cash equivalents, and restricted cash $ 138,360 $ 86,260
Inventories	Inventories consisted of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 204,463 $ 127,199 Work in progress 39,736 21,153 Finished goods 10,201 13,518 Service parts 9,210 7,697 Total inventories $ 263,610 $ 169,567
Property, Plant and Equipment, Net	Property, plant, and equipment, net, consisted of the following (in thousands): September 30, 2023 December 31, 2022 Computer hardware $ 6,116 $ 5,465 Computer software 17,111 11,012 Internally used vehicles and charging systems 11,778 15,177 Leased vehicles and batteries 5,142 5,142 Leasehold improvements 30,951 10,716 Machinery and equipment 80,795 28,942 Office furniture and equipment 3,397 2,523 Tooling 19,885 22,430 Finance lease right-of-use assets 878 179 Construction in progress 5,217 72,505 181,270 174,091 Less: Accumulated depreciation and amortization (72,861) (66,539) Total $ 108,409 $ 107,552
Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued payroll and related expenses $ 4,819 $ 8,647 Accrued legal and professional fees 17,649 1,586 Accrued sales and use tax 168 1,784 Warranty reserve — 8,406 Accrued supplier liability — 7,699 Insurance related — 4,445 Other accrued expenses 7,692 984 Total $ 30,328 $ 33,551
Other Long-Term Liabilities	Other long-term liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Warranty reserve $ 3,420 $ 17,107 Other long-term liabilities 1,579 57 Total $ 4,999 $ 17,164

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt Components	Debt, net of debt discount and issuance costs, consisted of the following (in thousands): September 30, 2023 December 31, 2022 Senior Credit Facility $ — $ — Convertible Notes 178,992 122,692 Total debt $ 178,992 $ 122,692 Less debt, current 178,992 122,692 Debt, non-current $ — $ —
Convertible Notes and Amended Notes	Immediately prior to the Convertible Notes Amendments, the Convertible Notes, net of debt discount and issuance costs, consisted of the following (in thousands): March 31, 2023 December 31, 2022 Principal $ 153,500 $ 153,500 PIK interest 19,196 17,301 Total principal 172,696 170,801 Less debt discount and issuance costs (44,275) (48,109) Total Convertible Notes $ 128,421 $ 122,692 Upon effectiveness of the Convertible Notes Amendments, the Convertible Notes, inclusive of debt premium, consisted of the following (in thousands): March 31, 2023 Principal $ 153,500 PIK interest 19,371 Total principal 172,871 Plus debt premium 4,864 Total Convertible Notes $ 177,735 As of September 30, 2023, the Convertible Notes consisted of the following (in thousands): September 30, 2023 Principal $ 153,500 PIK interest 25,492 Total principal $ 178,992

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Net Investment in Leases	The net investment in leases were as follows (in thousands): September 30, 2023 December 31, 2022 Net investment in leases, current $ 1,078 $ 985 Net investment in leases, non-current 9,771 9,304 Total net investment in leases $ 10,849 $ 10,289
Future Minimum Payments Receivable from Operating Leases	Future minimum payments receivable from operating and sales-type leases as of September 30, 2023 for each of the next five years were as follows: Operating leases Sales-type leases Remainder of 2023 $ 70 $ 229 2024 — 1,010 2025 — 1,762 2026 — 1,808 2027 — 1,808 Thereafter — 4,896 Total minimum lease payments $ 70 $ 11,513
Future Minimum Payments Receivable from Sales-Type Leases	Future minimum payments receivable from operating and sales-type leases as of September 30, 2023 for each of the next five years were as follows: Operating leases Sales-type leases Remainder of 2023 $ 70 $ 229 2024 — 1,010 2025 — 1,762 2026 — 1,808 2027 — 1,808 Thereafter — 4,896 Total minimum lease payments $ 70 $ 11,513
Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities as of September 30, 2023 were as follows (in thousands): Remainder of 2023 $ 1,725 2024 4,204 2025 3,487 2026 2,615 2027 2,238 Thereafter 9,858 Total undiscounted lease payment 24,127 Less: imputed interest (4,637) Total operating lease liabilities $ 19,490
Supplemental Cash Flow Information	Supplemental cash flow information related to leases were as follows (in thousands): Nine Months Ended September 30, 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ (6,295) $ (4,822) Lease liabilities arising from obtaining right-of-use assets: Operating lease $ — $ 4,178 Finance lease $ 699 $ —
Operating Lease Right-Of-Use Assets and Liabilities	Operating lease right-of-use assets and liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Operating leases Operating lease right-of-use assets $ 15,326 $ 20,274 Operating lease liabilities, current — 6,876 Operating lease liabilities, non-current — 18,098 Total operating lease liabilities $ — $ 24,974

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Reserved Shares of Common Stock	As of September 30, 2023, the Company had reserved shares of common stock for issuance as follows (in thousands): 2010 Equity Incentive Plan 10,317 2021 Equity Incentive Plan 34,537 2021 Employee Stock Purchase Plan 4,877 Warrants 1 Earnout Stock 18,009 Convertible notes 247,835 Total 315,576

Equity Plans and Stock-based _2

Equity Plans and Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock Option Activity	A summary of the Company’s stock option activity and related information was as follows: Options Outstanding Number of Stock Options Outstanding Weighted- Average Exercise Price Weighted-Average Remaining Contractual Life Aggregate Intrinsic Value Balance as of December 31, 2022 (1) 14,256,697 $ 4.32 5.5 $ 9,469 Granted 3,035,164 1.41 Exercised (57,036) 1.98 Cancelled/forfeited/expired (2) (3,250,706) 5.06 Balance as of September 30, 2023 13,984,119 $ 3.53 5.2 $ — Exercisable as of September 30, 2023 9,844,575 $ 3.80 3.5 $ — __________________ (1) Excluding Equity Awards of 2,677,500 shares and Milestone Options of 669,375 shares. See below for further details. (2) Excluding 2,677,500 shares cancelled under the Equity Awards with weighted average exercise price of $19.61 per share, and 669,375 shares cancelled under the Milestone Options with exercise price of $5.33 per share.
Assumptions for Fair Value of Stock Options	The fair value of stock options granted is estimated on the date of grant using the following assumptions: Nine Months Ended September 30, 2023 2022 Expected term (in years) 6.3 6.3 Risk-free interest rate 3.7 % 2.0 % Expected volatility 67.2 % 55.1 % Expected dividend rate — —
RSU Activity	A summary of the Company's RSU activity and related information is as follows: Number of RSUs Weighted Average Grant Date Fair Value Balance as of December 31, 2022 5,733,227 $ 7.07 Granted 5,154,438 1.60 Released (1,402,679) 6.77 Forfeited (2,079,799) 5.29 Balance as of September 30, 2023 7,405,187 $ 3.82
Stock-Based Compensation Expense	Stock-based compensation expense included in operating results was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Cost of goods sold $ 209 $ 456 $ 786 $ 1,350 Research and development 1,250 1,409 3,707 3,690 Selling, general and administrative 3,023 3,491 8,708 11,273 Total stock-based compensation expense $ 4,482 $ 5,356 $ 13,201 $ 16,313

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss Per Share	The computation of basic and diluted net loss per share of common stock attributable to common stockholders was as follows (in thousands, except for per share data): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Numerator: Net income (loss) $ 5,216 $ (65,061) $ (269,755) $ (156,960) Effect of dilutive securities: Interest expense to be recognized upon conversion of Convertible Notes (1) — (47,891) — (40,154) Numerator for diluted EPS - Net loss after the effect of dilutive securities $ 5,216 $ (112,952) $ (269,755) $ (197,114) Denominator: Weighted-average shares used in computing net loss per share of common stock, basic 227,869 225,291 227,192 223,782 Convertible Notes (1) — 25,413 — 24,855 Diluted weighted average shares 227,869 250,704 227,192 248,637 Net income (loss) per share of common stock: Basic $ 0.02 $ (0.29) $ (1.19) $ (0.70) Diluted $ 0.02 $ (0.45) $ (1.19) $ (0.79) __________________ (1) Adjustment is under the “if-converted” method. Adjustments for the three months ended September 30, 2022 include write-off of $59.0 million unamortized debt discount of the Convertible Notes as of June 30, 2022, offset by the $7.4 million interest expense recorded in net loss of three months ended September 30, 2022. Adjustments for the nine months ended September 30, 2022 include write-off of $62.3 million unamortized debt discount of the Convertible Notes as of December 31, 2021, offset by the $14.5 million interest expense recorded in net loss of nine months ended September 30, 2022.
Potentially Dilutive Securities Excluded from the Diluted Per Share Calculation	The potentially dilutive securities were as follows (in thousands): September 30, 2023 Stock options and RSUs to purchase common stock 21,389 Warrants to purchase common stock 1 Total 21,390

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	[1]
Accounting Policies [Abstract]
Accumulated deficit	$ (1,365,930)		$ (1,365,930)		$ (1,096,175)
Cash and cash equivalents and short-term investments	130,700		130,700
Asset impairment charge	$ 1,600	$ 0	$ 1,600	$ 0
Number of reportable segments | segment			1
[1]Derived from audited Consolidated Financial Statements.

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Revenue Disaggregated by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 86,148	$ 96,223	$ 251,391	$ 229,368
United States
Disaggregation of Revenue [Line Items]
Total revenue	68,480	82,040	201,585	195,680
Rest of World
Disaggregation of Revenue [Line Items]
Total revenue	$ 17,668	$ 14,183	$ 49,806	$ 33,688

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Credit Risk and Concentration (Details) - Customer Concentration Risk - customer	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Revenue
Concentration Risk [Line Items]
Number of customers accounted for 10% or more	3	2	1	2
Revenue | Customers Accounted For Greater Than 10%
Concentration Risk [Line Items]
Total % of customers accounted for 10% or more	62%	40%	24%	27%
Accounts Receivable
Concentration Risk [Line Items]
Number of customers accounted for 10% or more			3		2
Accounts Receivable | Customers Accounted For Greater Than 10%
Concentration Risk [Line Items]
Total % of customers accounted for 10% or more			52%		48%

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Deferred Revenue (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Change In Contract With Customer, Asset and Liability [Roll Forward]
Deferred revenue	$ 67,398
Revenue recognized from beginning balance during the nine months ended September 30, 2023	(17,336)
Deferred revenue added during the nine months ended September 30, 2023	33,756
Deferred revenue	$ 83,818

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 86,148	$ 96,223	$ 251,391	$ 229,368
Contract assets	3,200		3,200		$ 26,100
Remaining performance obligation	417,400		417,400
Charging systems and installation
Disaggregation of Revenue [Line Items]
Total revenue	$ 900	$ 3,700	$ 3,700	$ 5,800

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Revenue of Commercial Offerings (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 86,148	$ 96,223	$ 251,391	$ 229,368
Proterra Transit
Disaggregation of Revenue [Line Items]
Total revenue	25,770	56,363	91,745	142,563
Proterra Powered & Energy
Disaggregation of Revenue [Line Items]
Total revenue	$ 60,378	$ 39,860	$ 159,646	$ 86,805

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Product Warranties (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Movement in Standard Product Warranty Accrual [Roll Forward]
Warranty reserve- beginning of period	$ 25,513
Warranty costs incurred	(2,991)
Net changes in liability for pre-existing warranties, including expirations	(3,000)
Provision for warranty	13,501
Warranty reserve- end of period	$ 33,023

Chapter 11 Filing and Other R_3

Chapter 11 Filing and Other Related Matters - Narrative (Details) - USD ($) $ in Millions		9 Months Ended
	Aug. 04, 2023	Sep. 30, 2023
Reorganization, Chapter 11 [Line Items]
After tax amount		90 days
Executive Officer, Soell
Reorganization, Chapter 11 [Line Items]
Employee related charges	$ 0.5
Executive Officer, Bailey
Reorganization, Chapter 11 [Line Items]
Employee related charges	$ 0.5

Chapter 11 Filing and Other R_4

Chapter 11 Filing and Other Related Matters - Reorganization Items (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reorganizations [Abstract]
Professional fees and other bankruptcy related costs	$ 17,530		$ 17,530
Write-off of liabilities subject to compromise	(1,139)		(1,139)
Reorganization items, net	$ 16,391	$ 0	$ 16,391	$ 0

Chapter 11 Filing and Other R_5

Chapter 11 Filing and Other Related Matters - Liabilities Subject to Compromise (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	[1]
Reorganizations [Abstract]
Accounts payable	$ 73,947
Accrued liabilities	14,885
Deferred revenue	83,045
Operating lease liabilities	19,490
Total liabilities not subject to compromise	22,378
Liabilities subject to compromise	$ 213,745	$ 0
[1]Derived from audited Consolidated Financial Statements.

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets:
Total	$ 17,908	$ 239,300
Level 1 | U.S. Treasury securities
Assets:
Short-term investments	17,899	224,359
Level 1 | Money market funds
Assets:
Cash equivalents and marketable securities	$ 9	$ 14,941

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended	9 Months Ended
	Aug. 07, 2023	Jun. 23, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Long-term investments			$ 25,000		$ 25,000	$ 25,000		$ 26,600
Equity investment				$ 25,000
Asset impairment charge			$ 1,600	$ 0		$ 1,600	$ 0
Reclassification of derivative liability		$ 20,800			$ 20,800
Fair value of debt	$ 81,300

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Cash equivalents	$ 9	$ 14,941
Unrealized Loss	(6)	(545)
Amortized Cost	17,914	239,845
Estimated Fair Value	17,908	239,300
Cash equivalents: | Money market funds
Debt Securities, Available-for-sale [Line Items]
Cash equivalents	9	14,941
Short-term investments: | U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,905	224,904
Unrealized Loss	(6)	(545)
Estimated Fair Value	$ 17,899	$ 224,359

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Derivative Liability (Details) - USD ($) $ in Thousands		6 Months Ended
	Jun. 23, 2023	Sep. 30, 2023
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Fair value at issuance as of March 31, 2023		$ 135,678
Change in fair value		(114,878)
Reclassification of liability upon charter amendment	$ (20,800)	(20,800)
Fair value as of September 30, 2023		$ 0

Balance Sheet Components - Cash

Balance Sheet Components - Cash and Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022		Sep. 30, 2022	Dec. 31, 2021
Cash and Cash Equivalents
Cash	$ 112,805	$ 58,754
Cash equivalents	9	14,941
Total cash and cash equivalents	112,814	73,695	[1]
Cash, Cash Equivalents, and Restricted Cash
Cash and cash equivalents	112,814	73,695	[1]
Restricted cash, current portion	25,546	12,565	[1]
Total cash and cash equivalents, and restricted cash	$ 138,360	$ 86,260		$ 72,175	$ 182,604
[1]Derived from audited Consolidated Financial Statements.

Balance Sheet Components - Inve

Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 204,463		$ 204,463		$ 127,199
Work in progress	39,736		39,736		21,153
Finished goods	10,201		10,201		13,518
Service parts	9,210		9,210		7,697
Total inventories	263,610		263,610		$ 169,567	[1]
Write-down of inventories	$ 7,800	$ 0	$ 14,500	$ 0
[1]Derived from audited Consolidated Financial Statements.

Balance Sheet Components - Prop

Balance Sheet Components - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Finance lease right-of-use assets	$ 878		$ 878		$ 179
Property, plant and equipment, and finance lease right-of-use asset gross	181,270		181,270		174,091
Less: Accumulated depreciation and amortization	(72,861)		(72,861)		(66,539)
Total	108,409		108,409		107,552	[1]
Depreciation and amortization expense	5,500	$ 2,900	15,045	$ 9,583
Computer hardware
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,116		6,116		5,465
Computer software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	17,111		17,111		11,012
Internally used vehicles and charging systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,778		11,778		15,177
Leased vehicles and batteries
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,142		5,142		5,142
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	30,951		30,951		10,716
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	80,795		80,795		28,942
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,397		3,397		2,523
Tooling
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	19,885		19,885		22,430
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 5,217		$ 5,217		$ 72,505
[1]Derived from audited Consolidated Financial Statements.

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued payroll and related expenses	$ 4,819	$ 8,647
Accrued legal and professional fees	17,649	1,586
Accrued sales and use tax	168	1,784
Warranty reserve	0	8,406
Accrued supplier liability	0	7,699
Insurance related	0	4,445
Other accrued expenses	7,692	984
Total	$ 30,328	$ 33,551	[1]
[1]Derived from audited Consolidated Financial Statements.

Balance Sheet Components - Othe

Balance Sheet Components - Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Warranty reserve	$ 3,420	$ 17,107
Other long-term liabilities	1,579	57
Total liabilities	$ 4,999	$ 17,164	[1]
[1]Derived from audited Consolidated Financial Statements.

Debt - Components (Details)

Debt - Components (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total debt	$ 178,992		$ 122,692
Less debt, current	178,992		122,692	[1]
Debt, non-current	0		0
Line of credit | Senior Credit Facility
Debt Instrument [Line Items]
Total debt	0		0
Convertible debt | Convertible Notes
Debt Instrument [Line Items]
Total debt	$ 178,992	$ 177,735	$ 122,692
[1]Derived from audited Consolidated Financial Statements.

Debt - Senior Credit Facility (

Debt - Senior Credit Facility (Details) - USD ($)		1 Months Ended	3 Months Ended
	Aug. 07, 2023	May 31, 2019	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 4,700,000
Amount outstanding			$ 178,992,000	$ 122,692,000
Line of credit | Senior Credit Facility
Debt Instrument [Line Items]
Amount outstanding			0	0
Letters of credit outstanding, amount			12,000,000
Line of credit | Senior Credit Facility
Debt Instrument [Line Items]
Borrowing capacity		$ 75,000,000
Availability, period from maturity of subordinated debt		91 days
Availability, subordinated debt		$ 7,500,000
Commitment potential increase		50,000,000
Commitment potential reduction		$ 25,000,000
Termination notice period		15 days
Fixed charge coverage ratio		1
Unamortized debt issuance cost	$ 100,000
Amount outstanding			0	$ 0
Letters of credit outstanding, amount			11,900,000
Line of credit | Federal Funds Rate | Variable rate component one | Senior Credit Facility
Debt Instrument [Line Items]
Spread on variable interest rate		0.50%
Line of credit | London Interbank Offered Rate (LIBOR) | Variable rate component one | Senior Credit Facility
Debt Instrument [Line Items]
Spread on variable interest rate		1%
Line of credit | London Interbank Offered Rate (LIBOR) | Minimum | Variable rate component two | Senior Credit Facility
Debt Instrument [Line Items]
Spread on variable interest rate		1.50%
Line of credit | London Interbank Offered Rate (LIBOR) | Maximum | Variable rate component two | Senior Credit Facility
Debt Instrument [Line Items]
Spread on variable interest rate		3%
Line of credit | Base Rate | Minimum | Variable rate component two | Senior Credit Facility
Debt Instrument [Line Items]
Spread on variable interest rate		0%
Line of credit | Base Rate | Maximum | Variable rate component two | Senior Credit Facility
Debt Instrument [Line Items]
Spread on variable interest rate		1.50%
Letter of credit | Senior Credit Facility
Debt Instrument [Line Items]
Borrowing capacity		$ 25,000,000
Proceeds from Lines of Credit			$ 10,000,000

Debt - Convertible Notes and Am

Debt - Convertible Notes and Amended Notes (Details) - USD ($)					1 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended
	Aug. 07, 2023	Jun. 23, 2023	Mar. 31, 2023	Jun. 14, 2021	Aug. 31, 2020	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Jun. 22, 2023	May 19, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Special meeting of stockholders, period			6 months
Convertible Debt [Abstract]
Total debt						$ 178,992,000			$ 178,992,000	$ 178,992,000				$ 122,692,000
Loss on debt extinguishment						$ 0		$ 0		$ 177,939,000	$ (10,201,000)
Debt extinguishment fair value adjustment							$ 7,200,000
Common stock, shares authorized (in shares)		1,000,000,000				1,000,000,000			1,000,000,000	1,000,000,000		500,000,000		500,000,000
Reclassification of derivative liability		$ 20,800,000							$ 20,800,000
Fair value of debt	$ 81,300,000
Unamortized debt issuance cost	$ 4,700,000
Amortization of debt issuance cost and debt discounts										$ (922,000)	10,497,000
Additional Paid-in Capital
Convertible Debt [Abstract]
Debt extinguishment fair value adjustment							7,200,000
Convertible note warrants
Debt Instrument [Line Items]
Warrant to purchase shares of convertible preferred stock (in shares)					4,600,000
Fair value of embedded derivative liability					$ 68,500,000
Convertible note warrants | Convertible Notes
Debt Instrument [Line Items]
Exercise price of warrants (in dollars per share)					$ 0.02
Warrant liability					$ 29,000,000
Convertible debt
Debt Instrument [Line Items]
Write off of unamortized debt issuance cost								59,000,000			62,300,000
Convertible debt | Convertible Notes
Debt Instrument [Line Items]
Aggregate principal amount					$ 200,000,000
Interest rate					5%
Paid-in-kind interest rate					4.50%
Conversion terms, event of liquidation or sale, conversion price percentage					150%
Covenant, required minimum liquidity			$ 75,000,000		$ 75,000,000		$ 75,000,000
Covenant, required minimum liquidity, multiple factor of cash burn			4		4		4
Debt issuance costs incurred					$ 5,100,000
Debt amount converted				$ 46,500,000
Write off of unamortized debt issuance cost				21,000,000
Convertible Notes, conversion price (in dollars per share)					$ 6.5712
VWAP (in dollars per share)					$ 9.86
Consecutive days					20 days
Convertible Debt [Abstract]
Principal			$ 153,500,000				$ 153,500,000							$ 153,500,000
PIK interest			19,196,000				19,196,000							17,301,000
Total principal			172,696,000				172,696,000							170,801,000
Less debt discount and issuance costs/plus debt premium			(44,275,000)				(44,275,000)							(48,109,000)
Total debt			128,421,000				$ 128,421,000							122,692,000
Loss on debt extinguishment			177,900,000
Debt extinguishment fair value adjustment			$ 7,200,000
Amortization of debt issuance cost and debt discounts						$ (4,700,000)		$ 3,600,000		(1,000,000)	$ 10,400,000
Convertible debt | Convertible Notes
Debt Instrument [Line Items]
Aggregate principal amount													$ 3,500,000
Interest rate			12%				12%
Paid-in-kind interest rate			7%				7%
Covenant, required minimum liquidity			$ 125,000,000				$ 125,000,000
Fair value of embedded derivative liability			$ 135,700,000				135,700,000
Consecutive days			20 days
Face amount, maturity date not extended			$ 3,500,000				$ 3,500,000
Cash interest rate			5%				5%
PIK default rate			9%				9%
Conversion price discount percentage			75%				75%
Conversion price floor (in dollars per share)			$ 1.016				$ 1.016
Breach of minimum liquidity covenant, period			5 days
Beneficial ownership limitation percentage			40%				40%
Maximum shares to be issued, percentage			19.99%				19.99%
Maximum number of shares of common stock that may be issued, prior to stockholder approval of NASDAQ Proposal (in shares)			45,257,360				45,257,360
Maximum number of shares of common stock that may be issued, after stockholder approval of NASDAQ Proposal (in shares)			177,782,000				177,782,000
Convertible Debt [Abstract]
Principal			$ 153,500,000			153,500,000	$ 153,500,000		153,500,000	153,500,000
PIK interest			19,371,000			25,492,000	19,371,000		25,492,000	25,492,000
Total principal			172,871,000			178,992,000	172,871,000		178,992,000	178,992,000
Less debt discount and issuance costs/plus debt premium			4,864,000				4,864,000
Total debt			177,735,000			$ 178,992,000	177,735,000		$ 178,992,000	$ 178,992,000				$ 122,692,000
Fair value of debt			$ 313,400,000				$ 313,400,000
Convertible debt | Conversion scenario one | Convertible Notes
Debt Instrument [Line Items]
Percentage of principal amount to convert			33.33%				33.33%
Convertible Notes, conversion price (in dollars per share)			$ 4				$ 4
Convertible debt | Conversion scenario two | Convertible Notes
Debt Instrument [Line Items]
Percentage of principal amount to convert			33.33%				33.33%
Convertible Notes, conversion price (in dollars per share)			$ 5				$ 5
Convertible debt | Conversion scenario three | Convertible Notes
Debt Instrument [Line Items]
Convertible Notes, conversion price (in dollars per share)			$ 6				$ 6
Convertible debt | Conversion scenario four | Convertible Notes
Debt Instrument [Line Items]
Percentage of principal amount to convert			33.33%				33.33%
Convertible Notes, conversion price (in dollars per share)			$ 4				$ 4
Convertible debt | Conversion scenario five | Convertible Notes
Debt Instrument [Line Items]
Percentage of principal amount to convert			33.33%				33.33%
Convertible Notes, conversion price (in dollars per share)			$ 5				$ 5
Convertible debt | Conversion scenario six | Convertible Notes
Debt Instrument [Line Items]
Convertible Notes, conversion price (in dollars per share)			6				6
Convertible debt | Volume weighted average price, period one | Convertible Notes
Debt Instrument [Line Items]
Conversion provision, volume weighted average price (in dollars per share)			15				15
Convertible debt | Volume weighted average price, period two | Convertible Notes
Debt Instrument [Line Items]
Conversion provision, volume weighted average price (in dollars per share)			$ 12				$ 12
Convertible debt | Additional Paid-in Capital | Convertible Notes
Debt Instrument [Line Items]
Principal and interest reclassified to additional paid-in capital				$ 48,800,000

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Leases [Abstract]
Operating lease, expense	$ 2,000	$ 1,900	$ 6,000	$ 5,400
Total operating lease liabilities	$ 19,490		$ 19,490
Operating lease, weighted average remaining lease term	6 years 8 months 12 days		6 years 8 months 12 days		6 years 4 months 24 days
Operating lease, weighted average discount rate, percent	6.10%		6.10%		6.20%

Leases - Net Investment In Leas

Leases - Net Investment In Lease (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Leases [Abstract]
Net investment in leases, current	$ 1,078	$ 985
Net investment in leases, non-current	9,771	9,304
Total net investment in leases	$ 10,849	$ 10,289

Leases - Lessor Future Minimum

Leases - Lessor Future Minimum Payments Receivable (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Operating leases
Remainder of 2023	$ 70
2024	0
2025	0
2026	0
2027	0
Thereafter	0
Total minimum lease payments	70
Sales-type leases
Remainder of 2023	229
2024	1,010
2025	1,762
2026	1,808
2027	1,808
Thereafter	4,896
Total minimum lease payments	$ 11,513

Leases - Maturities Of Operatin

Leases - Maturities Of Operating Lease Liabilities (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Leases [Abstract]
Remainder of 2023	$ 1,725
2024	4,204
2025	3,487
2026	2,615
2027	2,238
Thereafter	9,858
Total undiscounted lease payment	24,127
Less: imputed interest	(4,637)
Total operating lease liabilities	$ 19,490

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ (6,295)	$ (4,822)
Lease liabilities arising from obtaining right-of-use assets:
Operating lease	0	4,178
Finance lease	$ 699	$ 0

Leases - Operating Lease Right-

Leases - Operating Lease Right-of-use Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Operating leases
Operating lease right-of-use assets	$ 15,326	$ 20,274	[1]
Operating lease liabilities, current	0	6,876	[1]
Operating lease liabilities, non-current	0	18,098	[1]
Total operating lease liabilities	$ 0	$ 24,974
[1]Derived from audited Consolidated Financial Statements.

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	[1]
Commitments and Contingencies Disclosure [Abstract]
Purchase commitment, outstanding inventory and other	$ 1,900,000
Long-term inventory prepayment	10,000	$ 10,000
Senior Credit Facility | Line of credit
Other Commitments [Line Items]
Letters of credit outstanding, amount	$ 12,000
[1]Derived from audited Consolidated Financial Statements.

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details)	9 Months Ended
	Sep. 30, 2023 vote $ / shares shares	Jun. 23, 2023 shares	Jun. 22, 2023 shares	Dec. 31, 2022 shares
Equity [Abstract]
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000	500,000,000	500,000,000
Capital stock, shares authorized (in shares)	1,010,000,000
Capital stock, par value (in dollars per share) | $ / shares	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000			10,000,000
Common stock, shares issued (in shares)	228,167,279			226,265,000
Common stock, shares outstanding (in shares)	228,167,279			226,265,000
Preferred stock, shares issued (in shares)	0			0
Preferred stock, shares outstanding (in shares)	0			0
Common stock, number of votes per share | vote	1

Stockholders' Equity - Reserved

Stockholders' Equity - Reserved Shares (Details) shares in Thousands	Sep. 30, 2023 shares
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	315,576
2021 Employee Stock Purchase Plan
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	4,877
Warrants
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	1
Earnout Stock
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	18,009
Convertible notes
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	247,835
2010 Equity Incentive Plan
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	10,317
2021 Equity Incentive Plan
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	34,537

Equity Plans and Stock-based _3

Equity Plans and Stock-based Compensation - Narrative (Details) - USD ($)			1 Months Ended		3 Months Ended				9 Months Ended
	Jun. 14, 2021	Jun. 11, 2021	Jun. 30, 2021	Mar. 31, 2020	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable, number of options (in shares)					9,844,575				9,844,575
Stock-based compensation expense					$ 4,482,000		$ 5,356,000		$ 13,201,000	$ 16,313,000
Awards granted (in shares)									3,035,164
Granted (in dollars per share)									$ 1.41
Total intrinsic value of stock options exercised									$ 100,000
Total estimated grant date fair value of stock options vested									5,000,000
Unrecognized stock-based compensation expense, stock options					$ 6,900,000				$ 6,900,000
2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable, number of options (in shares)	22,532,619				10,316,698				10,316,698
Common stock reserved for the plan (in shares)		387,531
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for the plan (in shares)		10,000,000
Annual percentage increase in shares reserved		4%
Additional shares reserved (in shares)						9,050,606		8,878,388
Percent of fair market value for greater than ten percent shareholders									110%
2021 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares that may be issued (in shares)									30,000,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for the plan (in shares)		1,630,000
Annual percentage increase in shares reserved		1%
Additional shares reserved (in shares)						2,262,651		2,219,597
Number of shares that may be issued (in shares)		16,300,000
ESPP, purchase price percentage									15%
ESPP, purchase price of common stock, percentage									85%
ESPP, maximum shares that may be purchased (in shares)									2,500
ESPP, offering period									6 months
ESPP, maximum amount that may be purchased									$ 25,000
CEO Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)				4,685,624
CEO Time-Based Awards tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Awards granted (in shares)				1,338,749
Granted (in dollars per share)				$ 5.33
CEO Time-Based Awards tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Awards granted (in shares)				2,677,500
CEO Time-Based Awards tranche two | Tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award exercise price (in dollars per share)				$ 11.21
CEO Time-Based Awards tranche two | Tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award exercise price (in dollars per share)				16.81
CEO Time-Based Awards tranche two | Tranche three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award exercise price (in dollars per share)				22.41
CEO Time-Based Awards tranche two | Tranche four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award exercise price (in dollars per share)				$ 28.02
Milestone Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 2,100,000
Awards granted (in shares)				669,375
Granted (in dollars per share)				$ 5.33
Number of shares that fully vested (in shares)	669,375
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period									10 years
Award vesting period									4 years
Unrecognized stock-based compensation expense, period for recognition									3 years
Stock options | Greater than ten percent stockholder
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period									5 years
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period									4 years
Unrecognized stock-based compensation expense, period for recognition									3 years
Unrecognized stock-based compensation expense, RSUs					$ 24,000,000				$ 24,000,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense									$ 800,000	$ 1,000,000
Shares of common stock issued under the ESPP (in shares)									586,008	325,106
Purchase price of common stock issued under the ESPP (in dollars per share)									$ 1.13	$ 4.62

Equity Plans and Stock-based _4

Equity Plans and Stock-based Compensation - Outstanding Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2020	Sep. 30, 2023	Dec. 31, 2022
Number of Stock Options Outstanding
Balance at beginning of period (in shares)		14,256,697
Granted (in shares)		3,035,164
Exercised (in shares)		(57,036)
Cancelled/forfeited/expired (in shares)		(3,250,706)
Balance at end of period (in shares)		13,984,119	14,256,697
Options exercisable, Number of options (in shares)		9,844,575
Weighted- Average Exercise Price
Balance at beginning of period (in dollars per share)		$ 4.32
Granted (in dollars per share)		1.41
Exercised (in dollars per share)		1.98
Cancelled/forfeited/expired (in dollars per share)		5.06
Balance at end of period (in dollars per share)		3.53	$ 4.32
Options exercisable, Weighted average exercise price per share (in dollars per share)		$ 3.80
Stock Options, Additional Disclosures
Options outstanding, Weighted average remaining contractual term		5 years 2 months 12 days	5 years 6 months
Options exercisable, Weighted average remaining contractual term		3 years 6 months
Options outstanding, Aggregate intrinsic value		$ 0	$ 9,469
Options exercisable, Aggregate intrinsic value		$ 0
Equity Awards
Number of Stock Options Outstanding
Balance at beginning of period (in shares)		2,677,500
Cancelled/forfeited/expired (in shares)		(2,677,500)
Balance at end of period (in shares)			2,677,500
Weighted- Average Exercise Price
Cancelled/forfeited/expired (in dollars per share)		$ 19.61
Milestone Options
Number of Stock Options Outstanding
Balance at beginning of period (in shares)		669,375
Granted (in shares)	669,375
Cancelled/forfeited/expired (in shares)		(669,375)
Balance at end of period (in shares)			669,375
Weighted- Average Exercise Price
Granted (in dollars per share)	$ 5.33
Cancelled/forfeited/expired (in dollars per share)		$ 5.33

Equity Plans and Stock-based _5

Equity Plans and Stock-based Compensation - Assumptions Used in Fair Value Measurement (Details) - Stock options	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 3 months 18 days	6 years 3 months 18 days
Risk-free interest rate	3.70%	2%
Expected volatility	67.20%	55.10%
Expected dividend rate	0%	0%

Equity Plans and Stock-based _6

Equity Plans and Stock-based Compensation - RSU Activity (Details) - Restricted stock units (RSUs)	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Number of RSUs
Balance at beginning of period (in shares) | shares	5,733,227
Granted (in shares) | shares	5,154,438
Released (in shares) | shares	(1,402,679)
Forfeited (in shares) | shares	(2,079,799)
Balance at end of period (in shares) | shares	7,405,187
Weighted Average Grant Date Fair Value
Balance at beginning of period (in dollars per share) | $ / shares	$ 7.07
Granted (in dollars per share) | $ / shares	1.60
Released (in dollars per share) | $ / shares	6.77
Forfeited (in dollars per share) | $ / shares	5.29
Balance at end of period (in dollars per share) | $ / shares	$ 3.82

Equity Plans and Stock-based _7

Equity Plans and Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 4,482	$ 5,356	$ 13,201	$ 16,313
Cost of goods sold
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	209	456	786	1,350
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,250	1,409	3,707	3,690
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,023	$ 3,491	$ 8,708	$ 11,273

Net Loss Per Share - Calculatio

Net Loss Per Share - Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Net income (loss)	$ 5,216	$ (65,061)	$ (269,755)	$ (156,960)
Effect of dilutive securities:
Interest expense to be recognized upon conversion of Convertible Notes	0	(47,891)	0	(40,154)
Numerator for diluted EPS - Net loss after the effect of dilutive securities	$ 5,216	$ (112,952)	$ (269,755)	$ (197,114)
Denominator:
Weighted-average shares used in computing net loss per share of common stock, basic (in shares)	227,869	225,291	227,192	223,782
Convertible Notes (in shares)	0	25,413	0	24,855
Diluted weighted average shares (in shares)	227,869	250,704	227,192	248,637
Net income (loss) per share of common stock:
Basic (in dollars per share)	$ 0.02	$ (0.29)	$ (1.19)	$ (0.70)
Diluted (in dollars per share)	$ 0.02	$ (0.45)	$ (1.19)	$ (0.79)
Convertible debt
Debt Instrument [Line Items]
Write off of unamortized debt issuance cost		$ 59,000		$ 62,300
Interest expense		$ 7,400		$ 14,500

Net Loss Per Share - Narrative

Net Loss Per Share - Narrative (Details) - Convertible debt - Convertible Notes	1 Months Ended
	Aug. 31, 2020 $ / shares
Debt Instrument [Line Items]
Convertible notes, conversion price (in dollars per share)	$ 6.5712
VWAP (in dollars per share)	$ 9.86
Consecutive days	20 days

Net Loss Per Share - Potentiall

Net Loss Per Share - Potentially Dilutive Securities (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2023 shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	21,390
Stock options and RSUs to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	21,389
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	1

401(k) Plan (Details)

401(k) Plan (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Retirement Benefits [Abstract]
Employer matching contribution, percent of match			4%
Employer matching contribution, cost	$ 0.9	$ 0.9	$ 2.9	$ 2.4

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Oct. 10, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Oct. 05, 2023	Dec. 31, 2022	[1]
Subsequent Event [Line Items]
Asset impairment charge		$ 1,600	$ 0	$ 1,600	$ 0
Long-term inventory prepayment		$ 10,000		$ 10,000			$ 10,000
Subsequent event
Subsequent Event [Line Items]
Aggregate amount	$ 1,400
Excess value	3%
Maximum amount						$ 1,500
[1]Derived from audited Consolidated Financial Statements.