Spruce Power Holding (SPRU) 10-K 1 Mar 22 2021 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 25, 2022	Jun. 30, 2021
Document Information Line Items
Entity Registrant Name	XL Fleet Corp.
Trading Symbol	XL
Document Type	10-K
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		141,409,508
Entity Public Float			$ 916,000,000
Amendment Flag	false
Entity Central Index Key	0001772720
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-38971
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-4109918
Entity Address, Address Line One	145 Newton Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02135
City Area Code	(617)
Local Phone Number	718-0329
Title of 12(b) Security	Shares of common stock, $0.0001 par value
Security Exchange Name	NYSE
Entity Interactive Data Current	Yes
Auditor Name	Marcum llp
Auditor Location	Melville, NY
Auditor Firm ID	688

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents		$ 351,676	$ 329,641
Restricted cash		150	150
Accounts receivable, net		6,477	10,559
Inventory, net		15,262	3,574
Prepaid expenses and other current assets		1,040	1,396
Total current assets		374,605	345,320
Property and equipment, net		3,495	579
Intangible assets, net		1,863	593
Right-of-use asset		4,564
Goodwill		8,606	489
Other assets		88	32
Total assets		393,221	347,013
Liabilities and stockholders’ equity Current liabilities:
Current portion of long-term debt		78	110
Accounts payable		3,799	4,372
Lease liability, current		900
Accrued expenses and other current liabilities		11,856	4,601
Total current liabilities		16,633	9,083
Long-term debt, net of current portion		21	98
Deferred revenue		691	305
Lease liability, non-current		3,599
Warrant liabilities		5,405	143,295
Contingent consideration		541	924
New market tax credit obligation	[1]	4,521	4,412
Total liabilities		31,411	158,117
Commitments and contingencies (Note 21)
Stockholders’ equity
Common stock, $0.0001 par value; 350,000,000 shares authorized at December 31, 2021 and December 31, 2020; 140,540,671 and 131,365,254 issued and outstanding at December 31, 2021 and 2020, respectively		14	13
Additional paid-in capital		461,207	317,084
Accumulated deficit		(99,411)	(128,201)
Total stockholders’ equity		361,810	188,896
Total liabilities and stockholders’ equity		$ 393,221	$ 347,013
[1]	Held by variable interest entity

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common stock, par value (in Dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	350,000,000	350,000,000
Common stock, issued	140,540,671	131,365,254
Common stock, outstanding	140,540,671	131,365,254

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenues	$ 15,600	$ 20,338	$ 7,215
Cost of revenues	16,296	17,594	8,075
Gross profit (loss)	(696)	2,744	(860)
Operating expenses:
Research and development	10,775	4,445	2,874
Selling, general, and administrative expenses	47,435	13,593	9,835
Loss from operations	(58,906)	(15,294)	(13,569)
Other (income) expense:
Interest expense, net	39	6,370	2,151
Loss on extinguishment of debt		1,038
Loss on asset disposal	26
Loss on impairment	3,000
Change in fair value of obligation to issue shares of common stock to sellers of World Energy	(565)
Change in fair value of warrant liability	(90,138)	35,015
Change in fair value of convertible notes payable derivative liability		2,889	(819)
Other income	(58)
Net (loss) income	$ 28,790	$ (60,606)	$ (14,901)
Net (loss) income per share, basic (in Dollars per share)	$ 0.21	$ (0.72)	$ (0.19)
Net loss per share, diluted (in Dollars per share)	$ 0.19	$ (0.72)	$ (0.19)
Weighted-average shares outstanding, basic (in Shares)	138,457,416	84,565,448	79,823,065
Weighted-average shares outstanding, diluted (in Shares)	148,510,351	84,565,448	79,823,065

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2018	$ 8	$ 53,522	$ (52,684)	$ 846
Balance (in Shares) at Dec. 31, 2018	79,451,338
Stock-based compensation expense		208		208
Stockholder distribution			(10)	(10)
Exercise of stock options		10		10
Exercise of stock options (in Shares)	44,154
Issuance of stock in asset acquisition		109		109
Issuance of stock in asset acquisition (in Shares)	458,902
Issuance of warrants		38		38
Issuance of restricted stock
Issuance of restricted stock (in Shares)	446,333
Net income (loss)			(14,901)	(14,901)
Balance at Dec. 31, 2019	$ 8	53,887	(67,595)	(13,700)
Balance (in Shares) at Dec. 31, 2019	80,400,727
Stock-based compensation expense		978		978
Conversion of convertible debt		17,446		17,446
Conversion of convertible debt (in Shares)	1,715,918
Exercise of warrants		114		114
Exercise of warrants (in Shares)	4,995,584
Exercise of stock options		884		$ 884
Exercise of stock options (in Shares)	488,625			488,860
Issuance of restricted stock
Issuance of restricted stock (in Shares)	25,309
PIC shares recapitalized, net of issuance costs and the fair value of warrant liabilities	$ 3	98,886		98,889
PIC shares recapitalized, net of issuance costs and the fair value of warrant liabilities (in Shares)	28,739,091
Shares issued in offering, net of issuance costs	$ 2	144,889		144,891
Shares issued in offering, net of issuance costs (in Shares)	15,000,000
Net income (loss)			(60,606)	(60,606)
Balance at Dec. 31, 2020	$ 13	317,084	(128,201)	188,896
Balance (in Shares) at Dec. 31, 2020	131,365,254
Stock-based compensation expense		3,508		3,508
Stock acceleration and extension		4,372		4,372
Exercise of warrants
Exercise of warrants (in Shares)	233,555
Exercise of public warrants	$ 1	85,554		85,555
Exercise of public warrants (in Shares)	7,441,020
Settlement of warrant liability upon exercise of warrants		47,162		47,162
Settlement of warrant liability upon call of warrants		591		591
Proceeds from PIC shares recapitalization		75		75
Exercise of stock options		230		$ 230
Exercise of stock options (in Shares)	1,027,519			1,032,819
Issuance of restricted stock
Issuance of restricted stock (in Shares)	11,319
Issuance of shares in business combination with World Energy		2,631		2,631
Issuance of shares in business combination with World Energy (in Shares)	462,004
Net income (loss)			28,790	28,790
Balance at Dec. 31, 2021	$ 14	$ 461,207	$ (99,411)	$ 361,810
Balance (in Shares) at Dec. 31, 2021	140,540,671

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net income (loss)	$ 28,790	$ (60,606)	$ (14,901)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Changes in fair value of warrant liabilities	(90,138)	35,015
Stock-based compensation	7,880	978	208
Loss on impairment	3,000
Bad debt expense	70		22
Depreciation and amortization expense	1,756	622	319
Contingent consideration	(61)	796	80
common stock to sellers of World Energy	(565)
Fair value change of derivative liabilities		2,889	(819)
Loss on extinguishment of debt		1,038
Loss on disposal of assets	26
Change in operating right-of-use assets	(23)
Interest on finance leases	37
Debt discount	72	4,629	1,598
Changes in operating assets and liabilities:
Accounts receivable, net	7,597	(9,400)	2,610
Inventory, net	(10,415)	(1,334)	215
Prepaid expenses and other current assets	456	(1,250)	260
Other assets	(31)	(2)	283
Accounts payable	(1,667)	3,823	(1,089)
Accrued expenses and other current liabilities	4,619	2,749	(450)
Deferred revenue	103	172	113
Net cash used in operating activities	(48,494)	(19,881)	(11,551)
Investing activities:
Payment to acquire net assets of World Energy	(8,188)
Purchase of eNow Convertible Note	(3,000)
Purchases of property and equipment	(3,641)	(145)	(28)
Net cash used in investing activities	(14,829)	(145)	(28)
Financing activities:
Proceeds from the issuance of subordinated convertible promissory notes		8,100	10,000
Repayments to the issuance of subordinated convertible promissory notes		(11,250)
Proceeds from paycheck protection program		1,100
Repayments to paycheck protection program		(1,100)
Proceeds from debt			2,500
Repayments of debt	(109)	(3,177)	(496)
Repayment of contingent consideration		(450)
Repayments under financing leases	(393)
Proceeds from revolving line of credit		2,500	(2,612)
Repayments of revolving line of credit		(2,500)
Proceeds from recapitalization of PIC shares	75	207,169
Proceeds from issuance of common stock		144,891
Proceeds of issuance costs in connection with term loans and revolving line of credit			(184)
Proceeds from exercise of stock options	230	114	10
Stockholder distribution			(10)
Proceeds from exercise of Public Warrants	85,555	884
Net cash provided by financing activities	85,358	346,281	9,208
Net increase in cash and cash equivalents and restricted cash	22,035	326,255	(2,371)
Cash, cash equivalents, and restricted cash at beginning of period	329,791	3,536	5,907
Cash, cash equivalents, and restricted cash at end of period	351,826	329,791	3,536
Supplemental disclosure of cash flow information:
Cash paid for interest	48	389
Supplemental disclosures of noncash investing and financing information:
Issuance of warrants			38
Initial measurement of warrants assumed in connection with the Business Combination accounted for as liabilities		108,280
Contingent and deferred consideration issued in connection with business combination			1,650
Issuance of stock in asset acquisition			109
Issuance costs in accrued expenses			25
Settlement of warrant liability upon exercise of Public Warrants	47,162
Settlement of warrant liability upon call of warrants	591
Issuance of shares to former owners of WEES	1,192
Conversion of convertible debt		17,446
Retrospective recapitalization of stockholders’ equity		51,005
Reduce derivative liability for extinguishment of convertible notes payable		(1,349)
Increase derivative liability for issuance of convertible notes payable		5,637
Reduce derivative liability for the conversion and repayment of the convertible notes payable		(8,526)
Equipment financing	$ 271

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2021
Organization and Description of Business [Abstract]
Organization and Description of Business	Note 1. Organization and Description of Business Description of Business: Merger and Reorganization: Acquisition of World Energy: COVID-19 Worldwide Pandemic: Consistent with the actions taken by governmental authorities, the Company has taken appropriately cautious steps to protect its workforce and support community efforts. As part of these efforts, and in accordance with applicable government directives, beginning in late March 2020, the Company implemented work from home policies where practical at its facilities. Effective December 31, 2021, all of the Company’s employees were working full-time from one of the Company’s five offices or from home. Current COVID-19 policies include universal facial covering requirements if not vaccinated, rearranging facilities to follow social distancing protocols, employees self-screening before going into the office, enhanced cleaning procedures, ability to go mask-free if proof of vaccination is provided to Human Resources, and strict quarantine protocols for any suspected or confirmed employee cases. However, the COVID-19 pandemic and the continued precautionary actions taken related to COVID-19 have adversely impacted, and are expected to continue to adversely impact, its operations, its contractors and the automotive original equipment manufacturers. The Company has experienced, and expects to continue to experience, reduced operations and production line shutdowns at vehicle OEMs due to COVID-19, limitations on travel by the Company’s personnel and personnel of the Company’s customers, and future delays or shutdowns of vehicle OEMs or the Company’s suppliers. The COVID-19 pandemic and the protocols and procedures the Company has implemented in response to the pandemic have caused some delays in operational activities. The full impact of the COVID-19 pandemic on its business and results of operations subsequent to December 31, 2021 will depend on future developments, such as the ultimate duration and scope of the outbreak and its impact on its operations and impact on its customers and industry partners.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Basis of consolidated financial statement presentation: Emerging Growth Company: Use of estimates: Segment Information: Concentration of Credit Risk: With respect to trade receivables, the Company routinely assesses the financial strength of its customers and, as a consequence, believes that the receivable credit risk exposure is limited. As of December 31, 2021, two customers accounted for approximately 74% and 11% of accounts receivable, net. As of December 31, 2020, one customer accounted for approximately 82% of accounts receivable, net. For the year ended December 31, 2021, two customers accounted for approximately 78% of revenues. For the years ended December 31, 2020, one customer accounted for approximately 68% of revenues and for December 31, 2019 two customers accounted for approximately 65% of revenues. Cash, cash equivalents, and restricted cash: Restricted cash: The following table provides a reconciliation of cash, cash equivalents, and restricted cash in the consolidated balance sheets to the total amount shown in the consolidated statements of cash flows: As of December 31, 2021 2020 Cash and cash equivalents $ 351,676 $ 329,641 Restricted cash 150 150 Total cash, cash equivalents, and restricted cash $ 351,826 $ 329,791 Accounts receivable, net: Inventory, net: Fair value measurements: The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from independent sources) and to minimize the use of unobservable inputs (internal assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1 Level 2 Level 3 An asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs. See Note 15 for additional information on assets and liabilities measured at fair value. The Company believes its valuation methods are appropriate and consistent with other market participants, however the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. The Company’s financial instruments consist of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued liabilities, contingent consideration liability, long-term debt and warrant liability. The carrying value of cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses approximates fair value because of the short-term nature of those instruments. Prepaid expenses and other current assets: Property and equipment, net: Equipment 5 years Furniture and fixtures 3 years Computer and related equipment 2 years Software 2 years Vehicles 5 years Leasehold improvements Lesser of useful life of the asset or remaining life of the lease Improvements are capitalized, while replacements, maintenance and repairs, which do not improve or extend the lives of the respective assets, are expensed as incurred. When property and equipment is retired or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts, and any gain or loss on the disposition is recorded in the statement of operations as a component of other (expense) income, net. Business combinations: The Company uses the income approach to determine the fair value of developed technology acquired in a business combination. This approach determines fair value by estimating the after-tax cash flows attributable to the respective asset over its useful life and then discounting these after-tax cash flows back to a present value. The Company bases its revenue assumptions on estimates of relevant market sizes, expected market growth rates, expected trends in technology and expected product introductions by competitors. Developed technology represents patented and unpatented technology and know-how. Refer to Note 4 for discussion of the Company’s 2021 business combination. Intangible assets, net: Impairment of long-lived assets: Impairment of goodwill: The Company performs its annual goodwill impairment assessment at October 1 each fiscal year, or more frequently if events or circumstances arise which indicate that goodwill may be impaired. An assessment can be performed by first completing a qualitative assessment on the Company’s single reporting unit. The Company can also bypass the qualitative assessment in any period and proceed directly to the quantitative impairment test, and then resume the qualitative assessment in any subsequent period. Qualitative indicators that may trigger the need for annual or interim quantitative impairment testing include, among other things, deterioration in macroeconomic conditions, declining financial performance, deterioration in the operational environment, or an expectation of selling or disposing of a portion of the reporting unit. Additionally, a significant change in business climate, a loss of a significant customer, increased competition, a sustained decrease in share price, or a decrease in estimated fair value below book value may trigger the need for interim impairment testing of goodwill. If the Company believes that, as a result of its qualitative assessment, it is more likely than not that the fair value of the reporting unit is less than its carrying amount, the quantitative impairment test is required. The quantitative test involves comparing the fair value of the reporting unit with its carrying amount, including goodwill. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss is recorded as a reduction to goodwill with a corresponding charge to earnings in the period the goodwill is determined to be impaired. The income tax effect associated with an impairment of tax-deductible goodwill is also considered in the measurement of the goodwill impairment. Any goodwill impairment is limited to the total amount of goodwill. The Company determines the fair value of its reporting unit using the market approach. Under the market approach method, the Company compared its book value to the fair value of its public float, utilizing the fair value of its common stock on the measurement date. Revenue: Revenue is recognized upon transfer of control to the customer, which occurs when the Company has a present right to payment, legal title has passed to the customer, the customer has the significant risks and rewards of ownership, and where acceptance is not a formality, the customer has accepted the product or service. For the Power Drive products, in general, transfer of control is upon shipment of the equipment as the terms are FOB shipping point or equivalent, as the Company has no other promised goods or services in its contracts with customers. In limited instances, the Company provides installation services to end-user fleet customers related to the purchased hybrid electric powertrain equipment. When provided, these installation services are not distinct within the context of the contract due to the fact that the end-use fleet customer is purchasing a completed modification to its vehicles and therefore, the installation services involve significant integration to integrate the hybrid electric powertrain equipment with the customer’s vehicle. As a result, the hybrid electric powertrain equipment and installation services represent a single performance obligation within these contracts with customers. The Company recognizes the revenue for the equipment sale and installation service for Power Drive products at the same time, which is after the installation is complete. The Company has elected to treat shipping and handling activities related to contracts with channel partner customers for Power Drive products as costs to fulfill the promise to transfer the associated equipment and not as a separate performance obligation. For the XL Grid solutions, in general, transfer of control is upon the acceptance and certification of project completion by both the end customer and the utility who is funding the energy incentives, representing a single performance obligation of the Company. Due to the short-term nature of projects (typically two to three weeks), the Company recognizes revenues from all XL Grid solutions activities at a point in time, when persuasive evidence of an arrangement exists, delivery has occurred, the price is fixed or determinable and the Company has the right to payment for the transferred asset. The Company also assesses multiple contracts entered into by the same customer in close proximity to determine if the contracts should be combined for revenue recognition purposes. During the duration of a project for XL Grid solutions, all direct material and labor costs and those indirect costs related to the project are capitalized, and customer deposits are treated as liabilities. Once a project has been completed and the energy efficiency upgrades have been deemed to meet client specifications, capitalized costs are charged to earnings. For both Power Drive and XL Grid solutions, when the Company’s contracts with customers contain multiple performance obligations, which is infrequent, the contract transaction price is allocated on a relative standalone selling price (SSP) basis to each performance obligation. The Company determines SSP based on observable selling prices for the sale of its systems. For extended warranties, the Company determines SSP based on expected cost plus margin. The Company establishes the margin based on review of market conditions and margins obtained by market participants for similar services. Any allocation of the transaction price required is determined at the contracts’ inception. The transaction price is the amount of consideration to which the Company expects to be entitled in exchange for transferring goods and services to the customer. Revenue is recorded based on the transaction price, which is solely made up of fixed consideration for its products and services. The Company does not adjust transaction price for the effects of a significant financing component when the period between the transfer of the promised good or service to the customer and payment for that good or service by the customer is expected to be one year or less. The Company has not identified any significant financing components to date. The Company’s sales can in certain instances include non-cash consideration in the form of the customer transferring to the Company, the customer’s rights to cash incentives from programs administered by municipalities related to hybrid vehicle programs that a customer is entitled to as a result of its purchase. The incentives are fixed amounts that are readily determinable. The Company values the non-cash consideration at its fair value, which generally is the amount of the Incentive. Payment terms on invoices range from 30 to 60 days. The Company excludes from revenue any sales tax and other government-assessed and imposed taxes on revenue generating activities that are invoiced to customers. The Company has elected to apply the practical expedient to expense costs to obtain contracts, which principally relate to sales commissions, at the time the liability is incurred when the expected amortization period is one year or less. Warranties: Guarantees. Customers of XL Grid solutions are provided limited-assurance-type warranties for a term of one year for installation work performed under its contracts. Warranties for equipment sold to customers are provided by the original equipment manufacturers. For both Power Drives and XL Grid solutions, the Company accrues the estimated cost of product warranties for unclaimed charges based on historical experiences and expected results. Should product failure rates and material usage costs differ from these estimated revisions to the estimated warranty liability are required. The Company periodically assesses the adequacy of its recorded product warranty liabilities and adjusts the balances as required. Warranty expense is recorded as a component of cost of product revenue in the statements of operations. Income taxes: Uncertain tax positions taken or expected to be taken in a tax return are accounted for using the more likely than not threshold for financial statement recognition and measurement. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. For the years ended December 31, 2021, 2020 and 2019, there were no uncertain tax position taken or expected to be taken in the Company’s tax returns. In the normal course of business, the Company is subject to regular audits by U.S. federal and state and local tax authorities. With few exceptions, the Company is no longer subject to federal, state or local tax examinations by tax authorities in its major jurisdictions for tax years before 2018. However, net operating loss carryforwards remain subject to examination to the extent they are carried forward and impact a year that is open to examination by tax authorities. The Company did not recognize any tax related interest or penalties in the accompanying consolidated financial statements, but would record any such interest and penalties as a component of the provision for income taxes. Share-based compensation: Stock Options The Company uses the Black-Scholes option pricing model to determine the fair value of stock-based awards, and recognizes the compensation cost on a straight line basis over the requisite service period of the awards for employee, which is typically the four-year vesting period of the award, and effective contract period specified in the award agreement for non-employee. The fair value of common stock is determined based on the closing price of the Company’s common stock on the New York Stock Exchange at each award grant date. The determination of the fair value of share-based payment awards utilizing the Black-Scholes model is affected by the stock price and a number of assumptions, including expected volatility, expected life, risk- free interest rate and expected dividends. The Company does not have a history of trading in its common stock as it was not a public company until December 21, 2020, and as such volatility was estimated using historical volatilities of comparable public entities. The expected life of the awards is estimated based on a simplified method, which uses the average of the vesting term and the original contractual term. The risk-free interest rate assumption is based on observed interest rates appropriate for the expected life of the awards. The dividend yield assumption is based on history and expectation of paying no dividends. Forfeitures are accounted for as they occur. The fair value of stock options issued for the years ended December 31, 2021, 2020, and 2019 was measured with the following assumptions: 2021 2020 2019 Expected volatility 78.1 – 88.2 % 79.6 – 90.5 % 70.0 % Expected term (in years) 6.25 6.2 – 10 6.1 – 10 Risk-free interest rate 0.1 – 1.3 % 0.3 – 1.6 % 1.4 – 3.0 % Expected dividend yield 0.0 % 0.0 % 0.0 % Restricted Stock Units Restricted stock units generally vest over the requisite service periods (vesting on a straight–line basis). The fair value of a restricted stock unit award is equal to the fair market value of a share of the Company’s Common stock on the grant date. The Company accounts for the forfeiture of equity awards as they occur. Warrant Liabilities: Research and development expense: Net income (loss) per share: Related parties: Recent accounting pronouncements issued and adopted: In February 2016, the Financial Accounting Standards Board (“FASB”) issued a new Accounting Standards Update (“ASU”) , Accounting Standards Codification Topic 842, Leases (“ASC 842”), related to leases to increase transparency and comparability among organizations by requiring the recognition of right-of-use (“ROU”) assets and lease liabilities on the balance sheet. Most significant among the changes in the standard is the recognition of ROU assets and lease liabilities by lessees for those leases classified as operating leases under previous U.S. GAAP. Under the new standard, disclosures are required to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The Company adopted ASC 842 effective January 1, 2021 and as a result, the Company recorded a ROU asset and lease liability within its consolidated financial statements (See Note 12). In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses of Financial Instruments

Merger with Pivotal Investment

Merger with Pivotal Investment Corporation II	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Merger with Pivotal Investment Corporation II	Note 3. Merger with Pivotal Investment Corporation II On the Closing Date, pursuant to the Merger Agreement, Merger Sub merged with and into Legacy XL, with Legacy XL surviving as a wholly owned subsidiary of XL Fleet Corp. On the Closing Date, each outstanding share of common stock of Legacy XL (including each share of Legacy XL’s common stock issued as a result of the conversion of Legacy XL’s preferred stock and any conversion or exchange of Legacy XL’s convertible promissory notes) was converted into the right to receive 0.75718950 shares (“Exchange Ratio”) of Pivotal’s common stock, par value $0.0001 per share. In connection with the consummation of the Business Combination, each outstanding share of Pivotal’s Class A common stock, par value $0.0001 per share (“Pivotal Class A Common Stock”), including (a) any shares of Pivotal’s Class B common stock, par value $0.0001 per share (“Pivotal Class B Common Stock”) that were converted into Pivotal Class A Common Stock in connection with the Merger and (b) any Pivotal units that were separated into the component securities, including Pivotal Class A Common Stock in connection with the Merger, was converted into one share of Common Stock. On the Closing Date, a number of purchasers (each, a “Subscriber”) purchased from the Company an aggregate of 15,000,000 shares of Common Stock (the “PIPE Shares”), for a purchase price of $10.00 per share and an aggregate purchase price of $150,000,000, pursuant to separate subscription agreements (each, a “Subscription Agreement” and the financing, the “PIPE”). Pursuant to the Subscription Agreements, the Company gave certain registration rights to the Subscribers with respect to the PIPE Shares. The sale of PIPE Shares was consummated concurrently with the Closing of the Merger. The Company assumed private placement warrants to purchase 4,233,333 shares of common stock, with an exercise price of $11.50 per share, and public warrants to purchase 7,666,667 shares of common stock, with an exercise price of $11.50 per share (See Note 15). Immediately prior to the Closing Date XL Fleet Corp. filed its Second Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, pursuant to which, among other things, XL Fleet Corp. (i) changed its name from Pivotal to “XL Fleet Corp.”, (ii) increased the number of shares of Pivotal Class A Common Stock it is authorized to issue to 350,000,000 shares, (iii) removed the provisions for the Pivotal Class B Common Stock (all such shares of Pivotal Class B Common Stock converted into shares of Pivotal Class A Common Stock in connection with the Business Combination) so that the Pivotal Class B Common Stock ceased to exist and the Company now has a single class of common stock (such resulting stock, the “Common Stock”), and (iv) removed the various provisions applicable only to special purpose acquisition corporations. Each of the options to purchase Legacy XL’s common stock, whether or not exercisable and whether or not vested, and each of the warrants to purchase Legacy XL’s common stock, in each case that was outstanding immediately prior to the effective time of the Business Combination, were assumed by XL Fleet Corp. on the Closing Date and converted into an option or warrant, as the case may be, to purchase a number of shares of Common Stock equal to the number of shares subject to such option or warrant immediately prior to the effective time multiplied by the Exchange Ratio, at an exercise price equal to the exercise price immediately prior to the effective time divided by the Exchange Ratio. Holders of Legacy XL’s outstanding convertible promissory notes were entitled to elect conversion or repayment of the principal amount of such notes, with accrued interest to be converted into shares of Legacy XL common stock. Immediately prior to the consummation of the Business Combination, the holders of such notes elected to have Legacy XL pay in cash an aggregate principal amount of $11,250,000 of such notes within three business days of the Closing Date. On the Closing Date XL Fleet Corp. issued an aggregate of 1,715,918 shares of its Common Stock upon conversion of the remaining outstanding principal amount and accrued interest. Immediately after the consummation of the Merger and prior to the consummation of PIPE, the former stockholders and option holders of Legacy XL owned, or held rights to acquire, approximately 75.2% of the fully-diluted common stock of Company, and Pivotal’s stockholders and option holders immediately prior to the Merger owned approximately 24.8% of the fully-diluted common stock of the Company. Based on the terms of the Merger, the transaction was treated as a reverse merger of the Company by Legacy XL. The merger was accounted for as a recapitalization of Legacy XL. Under this method of accounting, Pivotal was treated as the “acquired” company for financial reporting purposes. This determination was primarily based on Legacy XL comprising the ongoing operations of the combined company, Legacy XL senior management comprising the senior management of the combined company, and that the former owners and management of Legacy XL have control of the board of directors of the combined company after the Merger. In accordance with guidance applicable to these circumstances, the Merger was considered to be a capital transaction in substance. Accordingly, for accounting purposes, the Merger was treated as the equivalent of the Company issuing shares for the net assets of Pivotal, accompanied by a recapitalization. The net assets of Pivotal will be stated at historical cost, with no goodwill or other intangible assets recorded. Operations prior to the closing of the Merger will be those of the Company. The following table reconciles the elements of the Business Combination to the consolidated statements of cash flows and the consolidated statement of changes in stockholders’ equity (deficit) for the year ended December 31, 2020 (in thousands): Cash – Pivotal’s trust and cash (net of redemption) $ 231,975 Cash – PIPE 150,000 Less: transaction costs and advisory fees paid (29,915 ) Net Business Combination and PIPE financing $ 352,060

Business Combination

Business Combination	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Business Combination	Note 4. Business Combination World Energy On May 17, 2021, the Company acquired all of the issued and outstanding membership interests of World Energy, a privately-held, Massachusetts-based entity, and retained two of its principals and all of World Energy’s employees. World Energy is a direct-install energy efficiency services company (“ESCO”), serving commercial, industrial and institutional customers. World Energy enables utilities to meet their energy savings mandates by developing and executing energy efficiency projects. The acquisition of World Energy expanded the Company’s ability to deliver a comprehensive suite of energy savings services that enhances XL Grid’s solutions portfolio to include commercial and industrial EV charging, solar, and energy management services. The total purchase price consideration, as adjusted, is $12,461 for the acquisition of World Energy. During the year ended December 31, 2021, the Company remitted to the sellers of World Energy additional cash of $76 in connection with the finalization of working capital adjustments. The as-adjusted purchase price consisted of the following components: Cash of $8,496, as adjusted, consisting of the contractual purchase price of $8,000, plus working capital adjustments of an aggregate of $496. ● The closing date issuance of 231,002 shares of the Company’s common stock, valued at the closing price of $6.23 per share as of May 17, 2021, for a total share fair value upon issuance of $1,439; ● An obligation to issue 244,956 shares of the Company’s common stock to certain of the sellers and their advisors of World Energy, in three equal installments on the sixth, twenty-fourth and the thirtieth monthly anniversaries of the closing date. The closing date fair value was recorded at an aggregate amount of $1,526; ● An obligation to pay in cash an earnout of $1,000 upon World Energy’s achievement for the calendar year 2021 of minimum annual revenues of $19,500. The payment of the earnout is due within 30 days following the completion of the audit of XL Fleet’s financial statements for the fiscal year ending December 31, 2021. World Energy met the revenue requirements and as such, the Company expects to pay the $1,000 earnout shortly after the filing of this annual report on Form 10-K. The following details the final allocation of the purchase price consideration: Cash $ 8,000 Working capital adjustments 496 Fair value of 231,002 shares issued at closing 1,439 Fair value of the earnout 1,000 Portion of deferred obligation to issue shares of common stock 1,526 Total consideration 12,461 Less the fair value of assets acquired less liabilities assumed (4,344 ) Goodwill $ 8,117 Included in assets acquired was cash of $308. In connection with the acquisition of World Energy, the Company incurred an initial additional obligation to issue shares of its common stock to the three sellers, two of which also entered into employment agreements with the Company. Pursuant to the terms of the agreement, the Company was initially obligated to issue an aggregate of 448,050 shares of its common stock, issuable in three equal installments on November 17, 2021, on May 17, 2023 and on November 17, 2023, provided that seller/employee is employed by the Company at the date of issuance. If the seller/employee is not employed at such issuance date, the shares attributable to that seller/employee are forfeited. The Company determined that under relevant accounting guidance that this obligation to issue shares would be accounted for as compensation and not as purchase price consideration. Accordingly, the fair values of each of the three compensation share obligations are accreted as compensation over each relevant compensation period. For the year ended December 31, 2021, the Company recorded selling, general and administration expense of $1,049 related to this obligation. On November 17, 2021, the Company issued 231,002 shares of its common stock pursuant to this share obligation to the three sellers. The initial transaction with World Energy included an outstanding PPP loan of $507 that was incorporated in the liabilities assumed. During the third quarter of 2021, the PPP loan was forgiven in full which resulted in an additional payment to the sellers of World Energy. Consequently, the fair value of assets acquired less liabilities assumed was adjusted by the entire amount of the PPP loan that was forgiven, with a corresponding reduction in goodwill. The Company has accounted for this acquisition as a business combination under ASC Topic 805 “Business Combinations.” The acquisition method requires, among other things, that assets acquired and liabilities assumed in a business combination be recognized at their fair values as of the acquisition date. The fair values of the assets acquired and liabilities assumed by major class were recognized as follows: Amount Cash $ 308 Accounts receivable 3,585 Inventory, net 1,282 Prepaid expenses and other current assets 100 Property and equipment, net 173 Intangible assets, net 1,560 Right-of-use asset 145 Goodwill 8,117 Other assets 12 Accounts payable (1,096 ) Lease liability, current (56 ) Accrued expenses and other current liabilities (1,297 ) Deferred revenue (283 ) Lease liability, non-current (89 ) Total purchase consideration $ 12,461 The acquired intangible assets of $1,560 represents to the fair value of customer relationships which is amortized over three years. The estimated fair value of the intangible asset acquired was determined based on the income approach to measure the fair value of the customer relationships. This fair value measurement was based on significant inputs not observable in the market and thus represents a Level 3 measurement within the fair value hierarchy. Goodwill represents the excess of the purchase consideration over the estimated acquisition date fair value of the net tangible and intangible assets acquired. Goodwill is primarily attributable to expected post-acquisition synergies from integrating World Energy’s assembled workforce, products and processes into the Company’s product offerings. Goodwill recorded is not deductible for income tax purposes. Supplemental disclosure of pro forma information: The following unaudited pro forma financial information presents the combined results of the operations of XL Fleet and World Energy as if the acquisition of World Energy had occurred as of January 1, 2019. The unaudited pro forma financial information is not necessarily indicative of what the consolidated results of operations actually would have been had the respective acquisitions been completed on January 1, 2019. In addition, the unaudited pro forma financial information does not purport to project the future results of operations of the combined Company. The following table presents the Company’s pro forma combined results of operations for the years ended December 31, 2021, 2020, and 2019: 2021 2020 2019 Revenues $ 23,349 $ 38,230 $ 27,137 Net (loss) income $ 29,617 $ (59,216 ) $ (13,476 ) Per share amounts: Net (loss) income per share – basic $ 0.21 $ (0.70 ) $ (0.17 ) Net loss per share - diluted $ 0.20 $ (0.70 ) $ (0.17 ) The above pro forma information includes pro forma adjustments to remove the effect of the following non-recurring transactions: 1.) Non-recurring merger expenses of $498 were added back for the year ended December 31, 2021. 2.) Elimination of interest expense associated with debt that was repaid in the acquisition of World Energy of $37 for the year ended December 31, 2021, $94 for the year ended December 31, 2020 and $99 for the year ended December 31, 2019.

Settlement of Contingent Consid

Settlement of Contingent Consideration Quantum	12 Months Ended
	Dec. 31, 2021
Settlement Of Contingent Consideration Quantum [Abstract]
Settlement of Contingent Consideration Quantum	Note 5. Settlement of Contingent Consideration Quantum On October 4, 2019, pursuant to the terms of an asset purchase agreement, the Company acquired certain assets of Quantum Fuel Systems, LLC (“Quantum”) The purchase consideration included deferred payments or share issuances upon certain milestones being met. The final payments to the sellers of Quantum were: ● A cash payment of $450 paid on December 31, 2020 upon meeting a workforce retention milestone. ● Second milestone event was met on November 19, 2021 upon the achievement of certain product development criteria as outlined in the asset purchase agreement. In connection with having achieved the second milestone, in February 2022 the Company paid cash consideration of $475 and issued 50,000 shares of the Company’s common stock. ● Third milestone event was met on November 19, 2021 upon the successful demonstration of a prototype as outlined in the asset purchase agreement. In connection with having achieved the third milestone, in February 2022 the Company paid cash consideration of $475 and issued 50,000 shares of the Company’s common stock.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Note 6. Revenue The following table represents the Company’s revenues for the years ended December 31, 2021, 2020 and 2019, respectively, disaggregated, by sales channel. Disaggregation of revenue: 2021 2020 2019 Revenue from the sale of Power Drives: Revenue direct to customers $ 1,373 $ 4,013 $ 3,263 Revenue through channel partners 1,466 16,325 3,952 Revenue from the sale of XL Grid solutions – which are sold direct to customers 12,761 - - Total revenue $ 15,600 $ 20,338 $ 7,215 Remaining performance obligations: Contract Balances: Costs to obtain a contract: Warranties: The following is a roll-forward of the Company’s accrued warranty liability: 2021 2020 Balance at the beginning of the period $ 1,735 $ 1,009 Acquisition date accrual for World Energy acquisition 25 - Accrual for warranties issued 346 912 Accrual of additional warranty obligations 965 - Warranty fulfillment charges (524 ) (186 ) Balance at the end of the period $ 2,547 $ 1,735 The warranty liability is included in accrued expenses and other current liabilities on the consolidated balance sheets.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment	Note 7. Property and Equipment Property and equipment consisted of the following at December 31: As of December 31, 2021 2020 Equipment $ 1,437 $ 647 Furniture and fixtures 222 91 Computers 412 30 Software 500 359 Vehicles 902 622 Leasehold improvements 267 170 XL Grid projects not yet in service 1,593 - 5,333 1,919 Less accumulated depreciation (1,838 ) (1,340 ) Property and equipment, net $ 3,495 $ 579 Depreciation expense on property and equipment, was $653, $406 and $265 for the years ended December 31, 2021, 2020 and 2019, respectively.

Intangibles

Intangibles	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Intangibles	Note 8. Intangibles Intangible assets consist of: ● Developed technology acquired during 2019 with a gross value of $863 that is being amortized over a useful life of four years and that has accumulated amortization of $485, as of December 31, 2021, ● Sponsorship agreement contracted during 2021 with a gross value of $500 that is being amortized over a useful life of one year and has accumulated amortization of $250 as of December 31, 2021, and ● The initial direct cost related to customer energy efficiency agreement acquisition costs of $1,560 that is being amortized over three years and has accumulated amortization of $325. Approximate annual aggregate amortization expense of the intangibles for the years subsequent to December 31, 2021 is as follows: Year ending December 31: 2022 986 2023 682 2024 195 Total amortization $ 1,863 Amortization expense recognized on intangible assets was $791, $216 and $72 for the years ended December 31, 2021, 2020 and 2019, respectively.

Purchase of Convertible Note

Purchase of Convertible Note	12 Months Ended
	Dec. 31, 2021
Purchase Of Convertible Note [Abstract]
Purchase of Convertible Note	Note 9. Purchase of Convertible Note On July 15, 2021, XL Fleet made an investment of $3,000 into eNow, a developer of solar and battery power systems that is developing fully-electric transport refrigeration units (“eTRUs”) for Class 8 commercial trailers. In exchange for the investment, eNow issued to the Company a convertible debenture (the “eNow Convertible Note”) dated July 15, 2021 (the “Issuance Date”) in the original principal amount of $3,000, at the rate of 8% per annum and due on December 31, 2022. The investment was classified as an available-for-sale security. After reviewing the status of eNow’s financial condition on December 31, 2021, the Company determined that the investment in the eNow Convertible Note was fully impaired and as such recorded a charge of $3,000, reflected within other (income) expense as impairment of investment in the consolidated statements of operations. As discussed below, XL Fleet had an option to purchase eNow. If XL Fleet did not exercise this option, under certain circumstances the eNow Convertible Note would be converted on such date into Series B preferred stock. Interest on the outstanding principal sum of the eNow Convertible Note would commence accruing on the Issuance Date and computed on the basis of a 365-day year. The eNow Convertible Note did not convert at December 31, 2021. Pursuant to the terms of the eNow Convertible Note agreement, XL Fleet had the right to acquire eNow at a pre-determined valuation and had a right of first refusal with respect to competing offers to acquire eNow. In the fourth quarter of 2021, the Company notified eNow that it would not exercise its option to purchase eNow, which expired unexercised on December 31, 2021. In addition to the terms described above, on July 15, 2021 (“Effective Date”), XL Fleet entered into a Development and Supply Agreement (the “Development and Supply Agreement”) with eNow, whereby XL Fleet was made the exclusive provider of high voltage batteries and associated power systems for use in eNow eTRUs. The Company considered the existence of adverse conditions regarding the global supply chain crisis (chips, electronic hardware) that causes further impediments to eNow being able to execute on its business plan. XL Fleet evaluated the supply chain issues, specifically the lack of availability of batteries from third party suppliers. During the three months ended December 31, 2021, the supply chain issues worsened, and in particular the lack of availability of batteries from third party suppliers. These worsened conditions, in the Company’s opinion, negatively impacted eNow’s prospects and financial condition. In January 2022, due to the ongoing supply chain issues, the Company notified eNow of its intention to terminate the Development System Agreement (See Note 15).

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2021
Accrued Expenses and Other Current Liabilities [Abstract]
Accrued Expenses and Other Current Liabilities	Note 10. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following at December 31, 2021 and 2020: 2021 2020 Accrued warranty costs $ 2,548 $ 1,735 Accrued compensation and related benefits 2,254 1,001 Contingent purchase price consideration – Quantum 1,950 926 Deferred purchase price consideration – World Energy 278 - Accreted contingent compensation to sellers – World Energy 1,000 - Professional fees 949 723 Accrued settlements 494 Accrued expenses, other 2,383 216 $ 11,856 $ 4,601 Certain prior year amounts have been reclassified to conform to current year presentation.

New Markets Tax Credit Financin

New Markets Tax Credit Financing	12 Months Ended
	Dec. 31, 2021
New Markets Tax Credit Financing [Abstract]
New Markets Tax Credit Financing	Note 11. New Markets Tax Credit Financing On March 4, 2015, the Company entered into a financing transaction with U.S. Bancorp Community Development Corporation (U.S. Bank) under a qualified New Markets Tax Credit (“NMTC”) program related to the operation of the Company’s facility in Quincy, Illinois. The NMTC program was provided for in the Community Renewal Tax Relief Act of 2000 (the Act) and is intended to encourage capital investment in qualified lower income communities. The Act permits taxpayers to claim credits against their Federal income taxes for up to 39% of qualified investments in the equity of community development entities (CDEs). CDEs are privately managed investment institutions that are certified to make qualified low-income community investments. In connection with the financing, the Company made two loans totaling $10,454 to federal ($6,455 at 1.51%) and state ($3,999 at 1.53%) NMTC investment funds (the Investment Funds). Simultaneously, U.S. Bank made an equity investment of $4,995 to the Investment Funds and, by virtue of such contribution, is entitled to substantially all of the tax benefits derived from the NMTC. For compliance with the NMTC rules, principal payments on the loan would not begin until June 10, 2025 (the NMTC rules prohibit principal payments during the 7-year term of the NMTC arrangement). The maturity date on the loans would have been December 31, 2044. The Investment Funds then contributed the loan proceeds to a CDE, which, in turn, loaned combined funds of $15,000, net of debt issuance costs of $546, to XL Hybrid Quincy, LLC, a wholly-owned subsidiary of the Company, at an interest rate of 1.15% per year with a maturity date of March 4, 2045. These loans are secured by the leasehold improvements and equipment at the facility in Quincy, Illinois. Repayment of the loans would have commenced March 10, 2025. The proceeds from the loans from the CDE were used to partially fund the build-out of the facility in Quincy, Illinois. The transaction includes a put/call feature whereby, at the end of the seven-year NMTC compliance period, the Company may be obligated or entitled to repurchase U.S. Bank’s equity interest in the Investment Funds. U.S Bank exercised the put option in January 2022 the end of the recapture period. The value attributable to the put/call is anticipated to be nominal. The NMTC is subject to 100% recapture for a period of seven years as provided in the Internal Revenue Code. The Company is required to be in compliance with various regulations and contractual provisions that apply to the NMTC arrangement. Non-compliance with applicable requirements could have resulted in US Bank’s projected tax benefits not being realized and, therefore, could have required the Company to indemnify US Bank for any loss or recapture of NMTCs related to the financing. The Company has determined that no credit recapture was required in connection with this financing arrangement. The Company has determined that the financing arrangement with the Investment Fund and CDEs contains a variable interest entity (“VIE”). This conclusion was reached based on the following: ● The ongoing activities of the Investment Fund – collecting and remitting interest and fees and NMTC compliance – were all considered in the initial design and are expected to significantly affect the economic performance throughout the life of the Investment Fund; ● management considered the contractual arrangements that obligate the Company to comply with NMTC rules and regulations, deliver tax benefits, and provide various other guarantees to the structure; ● U.S. Bank’s lack of a material interest in the underlying economics of the project as a result of the guarantees, indemnifications, and put/call options; and ● the fact that the Company is obligated to absorb losses of the Investment Fund. As such, the Company concluded that it is the primary beneficiary of the VIE and consolidated the Investment Fund, as a VIE, in accordance with the accounting standards for consolidation. Because the Company consolidates an entity from which it has an approximately $10,500 loan receivable and consolidates an entity to which it owes an approximately $15,000 loan payable, these two balances partially eliminate against each other in consolidation. The $4,995 in net proceeds received in exchange for the transfer of tax credits were deferred and will be recognized by the Company when the tax benefits have been fully earned and delivered to US Bank without risk of recapture. During the years ended December 31, 2021 and 2020, the Company amortized debt issuance costs related to the NMTC of $72 and $78, respectively. The unamortized balance of debt issuance costs as of December 31, 2021 and 2020 was $20 and $91, respectively. On January 14, 2022, the NMTC financing arrangement was terminated and settled, with the note receivable of $15,000 (owed by XL Hybrid Quincy) being transferred to XL Hybrids LL in payment of the $10,500 note receivable. Both notes were retired resulting in a gain on forgiveness of debt of approximately $4,500.

ROU Assets and Lease Liabilitie

ROU Assets and Lease Liabilities	12 Months Ended
	Dec. 31, 2021
Regulatory Assets and Liabilities Disclosure [Abstract]
ROU Assets and Lease Liabilities	Note 12. ROU Assets and Lease Liabilities XL Fleet has entered into operating and finance leases as the lessee of office space, R&D and manufacturing facilities, and vehicles. On January 1, 2021 (“Effective Date”), the Company adopted FASB ASC 842, which increases transparency and comparability by recognizing a lessee’s rights and obligations resulting from leases by recording them on the balance sheet as lease assets and lease liabilities. The new guidance requires the recognition of the right-of-use (“ROU”) assets and related operating and finance lease liabilities on the balance sheet. The Company adopted the new guidance using the modified retrospective approach on January 1, 2021. As a result, the consolidated balance sheet as of December 31, 2020 was not restated and is not comparative. The adoption of ASC 842 resulted in the recognition of operating ROU assets of $3,481 and operating lease liabilities of $3,481 on the Company consolidated balance sheet as of January 1, 2021. The adoption of ASC 842 resulted in the recognition of finance ROU assets of $897 and finance lease liabilities of $897 on the Company’s consolidated balance sheet as of January 1, 2021. For contracts entered into on or after the Effective Date, at the inception of a contract the Company will assess whether the contract is, or contains, a lease. The Company’s assessment is based on: (i) whether the contract involves the use of a distinct identified asset, (ii) whether the Company obtained the right to substantially all the economic benefit from the use of the asset throughout the period, and (iii) whether the Company has the right to direct the use of the asset. Leases entered into prior to January 1, 2021, which were accounted for under ASC 840, were not reassessed for classification. For operating leases, the lease liability is initially and subsequently measured at the present value of the unpaid lease payments. For finance leases, the lease liability is initially measured in the same manner and date as for operating leases, and is subsequently presented at amortized cost using the effective interest method. The Company generally uses its incremental borrowing rate as the discount rate for leases, unless an interest rate is implicitly stated in the lease. The present value of the lease payments is calculated using the incremental borrowing rate for operating and finance leases, which was determined using a portfolio approach based on the rate of interest that the Company would have to pay to borrow an amount equal to the lease payments on a collateralized basis over a similar term. The lease term for all of the Company’s leases includes the noncancelable period of the lease plus any additional periods covered by either a Company option to extend the lease that the Company is reasonably certain to exercise, or an option to extend the lease controlled by the lessor. All ROU assets are reviewed periodically for impairment. Lease expense for operating leases consists of the lease payments plus any initial direct costs and is recognized on a straight-line basis over the lease term. Lease expense for finance leases consists of the amortization of the asset on a straight-line basis over the shorter of the lease term or its useful life and interest expense determined on an amortized cost basis, with the lease payments allocated between a reduction of the lease liability and interest expense. The Company’s operating leases are comprised primarily of office space and R&D and manufacturing facilities. Finance leases are comprised primarily of vehicle leases. Balance sheet information related to our leases is presented below (ASC 842 was adopted on January 1, 2021): December 31, January 1, December 31, Operating leases: Right-of-use assets $ 3,443 $ 3,481 $ – Lease liability, current 451 469 – Lease liability, non-current 3,056 3,012 – Finance leases: Right-of-use assets 1,121 897 – Lease liability, current 449 265 – Lease liability, non-current 543 632 – Other information related to leases is presented below: For the Year Ended 2021 Other information: Operating lease cost $ 855 As of 2021 Operating cash flows from operating leases $ 791 Weighted-average remaining lease term – operating leases (in months) 82.7 Weighted-average discount rate – operating leases 9.7 % As of December 31, 2021, the annual minimum lease payments of our operating lease liabilities were as follows: For The Years Ending December 31, 2022 770 2023 730 2024 694 2025 709 2026 555 Thereafter 1,416 Total future minimum lease payments, undiscounted 4,874 Less: imputed interest (1,367 ) Present value of future minimum lease payments $ 3,507

Note Payable

Note Payable	12 Months Ended
	Dec. 31, 2021
Note Payable [Abstract]
Note Payable	Note 13. Note Payable Paycheck Protection Program Loan In March 2021, World Energy entered into a Promissory Note (the “PPP Note”) with Boston Private Bank & Trust Company as the lender (the “Lender”), pursuant to which the Lender agreed to make a loan to the Company under the Paycheck Protection Program (the “PPP Loan”) offered by the U.S. Small Business Administration (the “SBA”) in a principal amount of $507 pursuant to Title 1 of the Coronavirus Aid, Relief and Economic Security Act (the “CARES Act”). This loan was forgiven by the SBA during July 2021and the Company recorded the forgiveness as an opening balance sheet adjustment in conjunction with the acquisition of World Energy. (See Note 4).

Debt

Debt	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt	Note 14. Debt At December 31, 2021 and 2020, the carrying value of debt was as follows: As of December 31, 2021 2020 Vehicle financing agreements $ 99 $ 208 Total debt obligations, net of deferred financing costs 99 208 Less: current portion of debt 78 110 Debt – net of current portion $ 21 $ 98 Bank term loan and revolver: In connection with the amendment to the Loan and Security Agreement executed in November 2019, the Company secured access to an additional term loan (Growth Capital Term Loan). The Term Loan and the Growth Capital Term Loan were repaid on December 23, 2020. Convertible notes payable: During the year ended December 31, 2020, the Company incurred a loss on extinguishment of $1,038 in connection with the amendment of $10,000 in face value of convertible notes. Specifically, during February of 2020, the Company entered into amendments of the convertible loan agreements with these note holders to extend the maturities to February 2021. The Company computed the discounted cash flows from these convertible notes as of the date of the amendment, both before and after the amendment. The Company determined that there was a greater than 10% change in the present value of these cash flows, and as such, the amendment qualified as an extinguishment. Pursuant to the relevant accounting guidance, the Company recorded a loss on extinguishment of debt of $1,038. The Company assessed these embedded features and determined that they were not considered clearly and closely related to the host notes, and met the definition of a derivative. Therefore, these embedded features were all required to be bifurcated from the notes and accounted for separately as a combined derivative liability. The Company estimated the fair value of the combined derivative liability which was recorded as a liability and as a discount net against the subordinated convertible notes. The Company was required to remeasure the combined derivative liability to its then fair value at each subsequent balance sheet date, through an adjustment to current earnings (See Note 15 for further details on the Company’s fair value measurements). The debt discount was amortized over the term of the associated debt agreement utilizing the effective interest method. The Company recorded $4,497 in amortization of these discounts as a component of interest expense during the year ended December 31, 2020. On December 21, 2020, the convertible notes and accrued interest were settled with the payment in cash of convertible notes in the amount of $11,250 and the issuance of 1,715,918 shares upon the conversion of convertible notes into principal and accrued interest of $6,850 and $1,709, respectively. Vehicle financing agreements

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 15. Fair Value Measurements Mark-to-Market Measurement The investment in the eNow Convertible Note was valued based upon a revenue multiple enterprise valuation. The contingent consideration related to the acquisition of Quantum Fuel Systems LLC (“Quantum”) and the earnout - World Energy were valued based upon the present value of the expected contingent consideration. The fair value of obligation to issue shares of common stock to the sellers of World Energy was based on the closing price of XL’s Common Stock on the reporting date. The Public Warrants were traded under the symbol XL.WS and the fair values were based upon the closing price of the Public Warrants at each measurement date. The Private Warrants were valued using a Black-Scholes model, pursuant to the inputs provided in the table below: Mark-to-Market Measurement at Mark-to-Market Measurement at December 31, December 31, Input 2021 2020 Risk-free rate 1.111 % 0.36 % Remaining term in years 3.98 4.98 Expected volatility 88.77 % 95.4 % Exercise price $ 11.50 $ 11.50 Fair value of common stock $ 3.31 $ 23.73 The following table sets forth the Company’s assets and liabilities which are measured at fair value on a recurring basis by level within the fair value hierarchy: Fair Value Measurements as of Level I Level II Level III Total Asset: Investment in eNow Convertible Note $ - $ - $ - $ - Liability: Private Warrants $ - $ - $ 5,404 $ 5,404 Contingent consideration – Quantum $ - $ - $ 1,950 $ 1,950 Earnout – World Energy $ - $ - $ 1,000 $ 1,000 Fair value of obligation to issue shares of common stock to sellers of World Energy $ - $ - $ 541 $ 541 Fair Value Measurements as of Level I Level II Level III Total Liability: Public Warrants $ 62,100 $ - $ - $ 62,100 Private Warrants $ - $ - $ 81,195 $ 81,195 Contingent consideration – (Quantum) $ - $ - $ 1,849 $ 1,849 During the year ended December 31, 2021, 7,441,020 Public Warrants were exercised, which resulted in the issuance of 7,441,020 shares of the Company’s Common Stock, generating cash proceeds of $85,555 and 225,647 Public Warrants were called at $0.01 per warrant. No Public Warrants remain outstanding as of December 31, 2021. The following is a roll forward of the Company’s Level 3 instruments: For the Years Ended Asset Liability Balance, January 1, 2020 $ - $ 2,852 Reduce derivative liability for extinguishment of convertible notes payable - (1,349 ) Increase derivative liability for issuance of convertible notes payable - 5,637 Private Placement Warrants assumed in connection with the Business Combination - 65,193 Fair value adjustments- Derivatives - 2,889 Fair value adjustments- Contingent consideration - 796 Fair value adjustments- Private Placement Warrants - 16,002 Reduce derivative liability for conversion and repayment of convertible notes - (8,526 ) Reduce contingent consideration for cash payment of a portion of obligation - (450 ) Balance, December 31, 2020 - 83,044 Obligation to issue shares of common stock to sellers of World Energy - 1,526 Fair value adjustment – Quantum contingent consideration - 101 Fair value adjustments – Warrant liability - (75,790 ) Fair value adjustments – World Energy - (565 ) Partial settlement of World Energy contingent consideration (421 ) Purchase of eNow Convertible Note at fair value 3,000 - Reserve for investment in convertible note (3,000 ) - Earnout – World Energy - 1,000 Balance, December 31, 2021 $ - $ 8,895

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Note 16. Stockholders’ Equity Common stock: The following shares of Common Stock are reserved for future issuance as of December 31, 2021: Warrants issued and outstanding 4,239,450 Restricted stock units issued and outstanding 606,638 Stock options issued and outstanding 9,737,292 Authorized for future grant of equity instruments under 2020 Equity Incentive Plan 11,003,180 Total 25,586,560

Warrants

Warrants	12 Months Ended
	Dec. 31, 2021
Warrants [Abstract]
Warrants	Note 17. Warrants Legacy XL Common Stock Warrants: During the year ended December 31, 2020, the Company issued 4,995,584 shares of Common Stock pursuant to the exercise of warrants which resulted in cash proceeds to the Company of $884. During the year ended December 31, 2021, 243,000 Legacy XL Warrants were exercised, which resulted in the issuance of 233,555 shares of the Company’s common stock, in a cashless exercise. A summary of the warrant activity for the years ended December 31 was as follows: Weighted Warrants Shares Exercise Outstanding at January 1, 2020 5,091,970 $ 0.26 Issued 177,229 0.70 Exercised (5,020,082 ) 0.34 Outstanding at January 1, 2021 249,117 $ 0.76 Issued - - Exercised (243,000 ) 0.76 Outstanding at December 31, 2021 6,117 $ 0.76 Exercisable at December 31, 2021 6,117 $ 0.76

Share-Based Compensation Expens

Share-Based Compensation Expense	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation Expense	Note 18. Share-Based Compensation Expense Share-based compensation expense for stock options, restricted stock awards and restricted stock units for the years ended December 31, 2021, 2020 and 2019 was $7,881, $978 and $208, respectively. As of December 31, 2021, there was $6,423 of unrecognized compensation cost related to stock options which is expected to be recognized over the remaining vesting periods, with a weighted-average period of 2.7 years. Stock Options During the years ended December 31, 2021 and 2020, the Company issued 1,232,844 and 2,738,912 options, respectively, to certain employees and board members that will vest over a period of one to four years. A summary of stock option award activity for the year ended December 31, 2021 was as follows: Options Shares Weighted Weighted Outstanding at December 31, 2019 10,087,296 0.25 7.4 Granted 2,738,912 1.76 Exercised (488,860 ) 0.24 Cancelled or forfeited (1,362,124 ) 0.74 Outstanding at December 31, 2020 10,975,224 $ 0.57 7.6 Granted 1,232,844 6.89 Exercised (1,032,819 ) 0.22 Cancelled or forfeited (1,437,957 ) 0.66 Outstanding at December 31, 2021 9,737,292 $ 1.40 7.2 Exercisable at December 31, 2021 7,380,232 $ 0.47 6.9 The aggregate intrinsic value of stock options outstanding as of December 31, 2021 was $24,777. The aggregate intrinsic value of stock options exercisable as of December 31, 2021 was $20,967. Cash received from options exercised for the years ended December 31, 2021, 2020 and 2019 was $229, $114 and $10, respectively. Restricted Stock Awards The fair value of restricted stock awards is estimated by the fair value of the Company’s Common Stock at the date of grant. Restricted stock activity during the year ended at December 31, 2021 was as follows: Number of Shares Weighted Average Grant Date Fair Value Per Share Non-vested, at December 31, 2019 446,332 0.24 Granted 25,309 9.21 Vested (25,309 ) 9.21 Non-vested, at December 31, 2020 446,332 $ 0.24 Granted - - Vested - - Cancelled or forfeited - Non-vested, at December 31, 2021 446,332 $ 0.24 Restricted Stock Units At December 31, 2021, the Company has 604,433 restricted stock units outstanding to certain employees and board members that will vest over a period of one to four years. The fair value of restricted stock unit awards is estimated by the fair value of the Company’s Common Stock at the date of grant. Restricted stock activity during the year ended at December 31, 2021 was as follows: Number of Weighted Non-vested, at beginning of period - $ - Granted 651,326 6.38 Vested (13,524 ) 14.17 Cancelled or forfeited (33,369 ) 8.92 Non-vested, at end of period 604,433 $ 6.06 As of December 31, 2021, 2,205 restricted stock units have vested that had not yet been settled into shares of Common Stock.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 19. Income Taxes Net deferred income tax assets consist of the following components as of December 31, 2021, 2020 and 2019: 2021 2020 2019 Deferred tax assets (liabilities): Net operating loss carryforwards $ 29,985 $ 20,898 $ 15,239 Tax credit carryforwards 1,840 1,341 1,341 Reserves 1,258 456 308 Share-based compensation 730 172 308 Allowance for impairment of eNow Convertible Note 701 - - Depreciation and amortization 229 (54 ) (16 ) Other 185 89 91 Total deferred tax assets, net 34,928 22,902 17,271 Less valuation allowance (34,928 ) (22,902 ) (17,271 ) Net deferred tax assets (liabilities) - - - A reconciliation of the provision for income taxes with the amounts computed by applying the statutory Federal income tax to income before provision for income taxes is as follows: For the Years Ended 2021 2020 U.S. federal statutory rate 21.0 % (21.0 )% State taxes, net of federal benefit 2.4 % (4.4 )% Change in fair value of warrant liability (73.6 )% 15.9 % Option and RSU expense 4.5 % 0.3 % Other 0.7 % (0.3 )% True-up to prior years return 3.2 % 0.2 % Change in valuation allowance 41.8 % 9.3 % Effective tax rate - % - % The Company utilizes an asset and liability approach for financial accounting and reporting for income taxes. The provision for income taxes is based upon income or loss after adjustment for those permanent items that are not considered in the determination of taxable income. Deferred income taxes represent the tax effects of differences between the financial reporting and tax basis of the Company’s assets and liabilities at the enacted tax rates in effect for the years in which the differences are expected to reverse. The Company evaluates the recoverability of deferred tax assets and establishes a valuation allowance when it is more likely than not that some portion or all the deferred tax assets will not be realized. Management makes judgments as to the interpretation of the tax laws that might be challenged upon an audit and cause changes to previous estimates of tax liability. In management’s opinion, adequate provisions for income taxes have been made. If actual taxable income by tax jurisdiction varies from estimates, additional allowances or reversals of reserves may be necessary. Tax benefits are recognized only for tax positions that are more likely than not to be sustained upon examination by tax authorities. The amount recognized is measured as the largest amount of benefit that is greater than 50 percent likely to be realized upon settlement. A liability for “unrecognized tax benefits” is recorded for any tax benefits claimed in the Company’s tax returns that do not meet these recognition and measurement standards. For the years ended December 31, 2021, 2020 and 2019, no liability for unrecognized tax benefits was required to be reported. The Company has provided a full valuation allowance against its net deferred tax assets since realization of any future benefit from deductible temporary differences and net operating loss cannot be sufficiently assured. Management of the Company has evaluated the positive and negative evidence bearing upon the reliability of its deferred tax assets, which are comprised principally of net operating loss carryforwards and research and development credits. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets. During the year ended December 31, 2021 and 2020, the Company increased its valuation allowance by $12,026 and $5,659, respectively. As of December 31, 2021, the Company has federal and state net operating loss carryforwards of approximately $122,000 and $69,000, respectively, approximately $31,300 of the federal net operating loss carryforward will expire at various dates commencing on 2029 and through 2037 and $90,700 were generated between the years ended December 31, 2018 and 2021 and have an indefinite life. At December 31, 2021, the Company has federal and state tax credits of approximately $1,452 and $388, respectively. These federal and state tax credits are available to reduce future taxable income and expire at various dates commencing 2026 through 2039. Utilization of the NOLs and tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986 due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating loss and tax credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. The Company has not determined whether an ownership change under section 382 has occurred or whether such limitation exists.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Note 20. Related Party Transactions Operating lease: Rent expense under the operating lease for the years ended December 31, 2021, 2020 and 2019 was $231, $235 and $235, respectively. Future minimum lease payments for this lease are as follows: 2022 156 Total $ 156

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 21. Commitments and Contingencies Sponsorship Commitment: Equipment Purchase: Purchase Commitments: Legal proceedings: Beginning on March 8, 2021, two putative securities class action complaints were filed in the federal district court for the Southern District of New York against the Company and certain of its current and former officers and directors. Those cases were consolidated and a lead plaintiff appointed in June 2021, and an amended complaint filed on July 20, 2021 alleging that certain public statements made by the defendants between October 2, 2020 and March 2, 2021 violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder. The Company believes that the allegations asserted in the amended complaint are without merit, and the Company intends to vigorously defend the lawsuit. There can be no assurance, however, that the Company will be successful. At this time, the Company is unable to estimate potential losses, if any, related to the lawsuit. On September 20, 2021, and October 19, 2021, two class action complaints were filed in the Delaware Court of Chancery against certain of the Company’s current officers and directors, and the Company’s sponsor, Pivotal Investment Holdings II LLC. The actions were consolidated as In re XL Fleet (Pivotal) Stockholder Litigation On January 6, 2022, the Company received a subpoena from the Securities and Exchange Commission (the “SEC”) requesting the production of certain documents related to, among other things, the Company’s business combination with XL Hybrids, Inc. and the related PIPE financing, the Company’s sales pipeline and revenue projections, purchase orders, suppliers, CARB approvals, fuel economy from our Power Drive products, customer complaints, and disclosures and other matters in connection with the foregoing. The SEC has informed the Company that its current investigation is a fact-finding inquiry. The SEC has also informed the Company that the investigation does not mean that it has concluded that anyone has violated the law, and does not mean that it has a negative opinion of any person, entity or security. We intend to provide the requested information and cooperate fully with the SEC investigation.

Leadership Transition

Leadership Transition	12 Months Ended
	Dec. 31, 2021
Leadership Transition Disclosures [Abstract]
Leadership Transition	Note 22. Leadership Transition On November 1, 2021, the Company entered into an executive employment agreement with Eric Tech (the “Employment Agreement”), pursuant to which Mr. Tech became the Company’s CEO effective December 1, 2021. On November 20, 2021, the Company entered into a separation agreement with Dimitri Kazarinoff, the Chief Executive Officer. Mr. Kazarinoff’s employment ended effective December 1, 2021. In connection with the separation agreement, the Company agreed to accelerate the vesting of all outstanding stock options by one year, extend the exercise period of the stock options to two years, and pay twelve months of severance. Due to the modification of his options, the Company recorded the incremental value of $4,372 as an expense during the year ended December 31, 2021. On January 31, 2022, the Company’s Chief Financial Officer resigned. An interim replacement was named while the Company completes the search for a permanent replacement.

Net (Loss) Income Per Share

Net (Loss) Income Per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Net (Loss) Income Per Share	Note 23. Net (Loss) Income Per Share The following is a reconciliation of the numerator and denominator used to calculate basic earnings per share and diluted earnings per share for the years ended December 31, 2021, 2020 and 2019: Years Ended December 31, 2021 2020 2019 Numerator: Net income (loss) $ 28,790 $ (60,606 ) $ (14,901 ) Denominator: Weighted average shares basic 138,457,416 84,565,448 79,823,065 Dilutive effect of option, warrants and restricted stock units 10,052,935 - - Weighted average shares outstanding, basic and diluted 148,510,351 84,565,448 79,823,065 Net income (loss) per share, basic $ 0.21 $ (0.72 ) $ (0.19 ) Net income (loss) per share, diluted $ 0.19 $ (0.72 ) $ (0.19 ) Potential dilutive securities, which include stock options, warrants and restricted stock units have been excluded from the computation of diluted net loss per share for the years ended December 31, 2020 and 2019 as the effect would be to reduce the net loss per share. Therefore, for these periods the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. For the year ended December 31, 2021, certain dilutive securities were excluded from the computation of diluted earnings per share as the effect would have been to increase net earnings per share. The number of shares underlying outstanding dilutive securities which have been excluded from the computation of diluted net loss per share above, are presented below: Years Ended December 31, 2021 2020 2019 Stock options 361,292 10,975,222 10,087,294 Private Warrants 4,233,333 11,900,000 - XL Legacy Warrants - 249,117 5,849,164 Total 4,594,625 23,124,339 15,936,458

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Retirement Plan	Note 24. Retirement Plan The Company has adopted a 401(k) plan to provide all eligible employees a means to accumulate retirement savings on a tax-advantaged basis. The 401(k) plan requires participants to be at least 21 years old. In addition to the traditional 401(k), eligible employees are given the option of making an after- tax contribution to a Roth 401(k) or a combination of both. Plan participants may make before tax elective contributions up to the maximum percentage of compensation and dollar amount allowed under the Internal Revenue Code. Participants are allowed to contribute, subject to IRS limitations on total annual contributions from 1% to 90% of eligible earnings. The plan provides for automatic enrollment at a 3% deferral rate of an employee’s eligible wages. The Company provides for safe harbor matching contributions equal to 100% on the first 3% of an employee’s eligible earnings deferred and an additional 50% on the next 2% of an employee’s eligible earnings deferred. Employee elective deferrals and safe harbor matching contributions are 100% vested at all times. In connection with the acquisition of World Energy, XL Fleet adopted the World Energy 401(k) plan whose features are the same as those of the XL Fleet 401(k) plan except that (i) Participants are allowed to contribute, subject to IRS limitations on total annual contributions from 1% to 100% of eligible earnings and (ii) the safe harbor non-elective contribution is equal to 3% of employee’s compensation.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Note 25. Subsequent Event Management has reviewed material events subsequent of the period ended December 31, 2021 and prior to the filing of financial statements in accordance with FASB ASC 855 “Subsequent Events”. In February 2022, the Company eliminated 51 positions as part of a strategic realignment to narrow its focus and reduce some aspects of the Company’s hybrid offerings. In connection with the elimination of these positions, the Company incurred severance charges totaling $1,251.

Accounting Policies, by Policy

Accounting Policies, by Policy (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of consolidated financial statement presentation	Basis of consolidated financial statement presentation:
Emerging Growth Company	Emerging Growth Company:
Use of estimates	Use of estimates:
Segment Information	Segment Information:
Concentration of Credit Risk	Concentration of Credit Risk: With respect to trade receivables, the Company routinely assesses the financial strength of its customers and, as a consequence, believes that the receivable credit risk exposure is limited. As of December 31, 2021, two customers accounted for approximately 74% and 11% of accounts receivable, net. As of December 31, 2020, one customer accounted for approximately 82% of accounts receivable, net. For the year ended December 31, 2021, two customers accounted for approximately 78% of revenues. For the years ended December 31, 2020, one customer accounted for approximately 68% of revenues and for December 31, 2019 two customers accounted for approximately 65% of revenues.
Cash, cash equivalents, and restricted cash	Cash, cash equivalents, and restricted cash:
Restricted cash	Restricted cash: The following table provides a reconciliation of cash, cash equivalents, and restricted cash in the consolidated balance sheets to the total amount shown in the consolidated statements of cash flows: As of December 31, 2021 2020 Cash and cash equivalents $ 351,676 $ 329,641 Restricted cash 150 150 Total cash, cash equivalents, and restricted cash $ 351,826 $ 329,791
Accounts receivable, net	Accounts receivable, net:
Inventory, net	Inventory, net:
Fair value measurements	Fair value measurements: The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from independent sources) and to minimize the use of unobservable inputs (internal assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1 Level 2 Level 3 An asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs. See Note 15 for additional information on assets and liabilities measured at fair value. The Company believes its valuation methods are appropriate and consistent with other market participants, however the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. The Company’s financial instruments consist of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued liabilities, contingent consideration liability, long-term debt and warrant liability. The carrying value of cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses approximates fair value because of the short-term nature of those instruments.
Prepaid expenses and other current assets	Prepaid expenses and other current assets:
Property and equipment, net	Property and equipment, net: Equipment 5 years Furniture and fixtures 3 years Computer and related equipment 2 years Software 2 years Vehicles 5 years Leasehold improvements Lesser of useful life of the asset or remaining life of the lease Improvements are capitalized, while replacements, maintenance and repairs, which do not improve or extend the lives of the respective assets, are expensed as incurred. When property and equipment is retired or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts, and any gain or loss on the disposition is recorded in the statement of operations as a component of other (expense) income, net.
Business combinations	Business combinations: The Company uses the income approach to determine the fair value of developed technology acquired in a business combination. This approach determines fair value by estimating the after-tax cash flows attributable to the respective asset over its useful life and then discounting these after-tax cash flows back to a present value. The Company bases its revenue assumptions on estimates of relevant market sizes, expected market growth rates, expected trends in technology and expected product introductions by competitors. Developed technology represents patented and unpatented technology and know-how. Refer to Note 4 for discussion of the Company’s 2021 business combination.
Intangible assets, net	Intangible assets, net:
Impairment of long-lived assets	Impairment of long-lived assets:
Impairment of goodwill	Impairment of goodwill: The Company performs its annual goodwill impairment assessment at October 1 each fiscal year, or more frequently if events or circumstances arise which indicate that goodwill may be impaired. An assessment can be performed by first completing a qualitative assessment on the Company’s single reporting unit. The Company can also bypass the qualitative assessment in any period and proceed directly to the quantitative impairment test, and then resume the qualitative assessment in any subsequent period. Qualitative indicators that may trigger the need for annual or interim quantitative impairment testing include, among other things, deterioration in macroeconomic conditions, declining financial performance, deterioration in the operational environment, or an expectation of selling or disposing of a portion of the reporting unit. Additionally, a significant change in business climate, a loss of a significant customer, increased competition, a sustained decrease in share price, or a decrease in estimated fair value below book value may trigger the need for interim impairment testing of goodwill. If the Company believes that, as a result of its qualitative assessment, it is more likely than not that the fair value of the reporting unit is less than its carrying amount, the quantitative impairment test is required. The quantitative test involves comparing the fair value of the reporting unit with its carrying amount, including goodwill. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss is recorded as a reduction to goodwill with a corresponding charge to earnings in the period the goodwill is determined to be impaired. The income tax effect associated with an impairment of tax-deductible goodwill is also considered in the measurement of the goodwill impairment. Any goodwill impairment is limited to the total amount of goodwill. The Company determines the fair value of its reporting unit using the market approach. Under the market approach method, the Company compared its book value to the fair value of its public float, utilizing the fair value of its common stock on the measurement date.
Revenue	Revenue: Revenue is recognized upon transfer of control to the customer, which occurs when the Company has a present right to payment, legal title has passed to the customer, the customer has the significant risks and rewards of ownership, and where acceptance is not a formality, the customer has accepted the product or service. For the Power Drive products, in general, transfer of control is upon shipment of the equipment as the terms are FOB shipping point or equivalent, as the Company has no other promised goods or services in its contracts with customers. In limited instances, the Company provides installation services to end-user fleet customers related to the purchased hybrid electric powertrain equipment. When provided, these installation services are not distinct within the context of the contract due to the fact that the end-use fleet customer is purchasing a completed modification to its vehicles and therefore, the installation services involve significant integration to integrate the hybrid electric powertrain equipment with the customer’s vehicle. As a result, the hybrid electric powertrain equipment and installation services represent a single performance obligation within these contracts with customers. The Company recognizes the revenue for the equipment sale and installation service for Power Drive products at the same time, which is after the installation is complete. The Company has elected to treat shipping and handling activities related to contracts with channel partner customers for Power Drive products as costs to fulfill the promise to transfer the associated equipment and not as a separate performance obligation. For the XL Grid solutions, in general, transfer of control is upon the acceptance and certification of project completion by both the end customer and the utility who is funding the energy incentives, representing a single performance obligation of the Company. Due to the short-term nature of projects (typically two to three weeks), the Company recognizes revenues from all XL Grid solutions activities at a point in time, when persuasive evidence of an arrangement exists, delivery has occurred, the price is fixed or determinable and the Company has the right to payment for the transferred asset. The Company also assesses multiple contracts entered into by the same customer in close proximity to determine if the contracts should be combined for revenue recognition purposes. During the duration of a project for XL Grid solutions, all direct material and labor costs and those indirect costs related to the project are capitalized, and customer deposits are treated as liabilities. Once a project has been completed and the energy efficiency upgrades have been deemed to meet client specifications, capitalized costs are charged to earnings. For both Power Drive and XL Grid solutions, when the Company’s contracts with customers contain multiple performance obligations, which is infrequent, the contract transaction price is allocated on a relative standalone selling price (SSP) basis to each performance obligation. The Company determines SSP based on observable selling prices for the sale of its systems. For extended warranties, the Company determines SSP based on expected cost plus margin. The Company establishes the margin based on review of market conditions and margins obtained by market participants for similar services. Any allocation of the transaction price required is determined at the contracts’ inception. The transaction price is the amount of consideration to which the Company expects to be entitled in exchange for transferring goods and services to the customer. Revenue is recorded based on the transaction price, which is solely made up of fixed consideration for its products and services. The Company does not adjust transaction price for the effects of a significant financing component when the period between the transfer of the promised good or service to the customer and payment for that good or service by the customer is expected to be one year or less. The Company has not identified any significant financing components to date. The Company’s sales can in certain instances include non-cash consideration in the form of the customer transferring to the Company, the customer’s rights to cash incentives from programs administered by municipalities related to hybrid vehicle programs that a customer is entitled to as a result of its purchase. The incentives are fixed amounts that are readily determinable. The Company values the non-cash consideration at its fair value, which generally is the amount of the Incentive. Payment terms on invoices range from 30 to 60 days. The Company excludes from revenue any sales tax and other government-assessed and imposed taxes on revenue generating activities that are invoiced to customers. The Company has elected to apply the practical expedient to expense costs to obtain contracts, which principally relate to sales commissions, at the time the liability is incurred when the expected amortization period is one year or less.
Warranties	Warranties: Guarantees. Customers of XL Grid solutions are provided limited-assurance-type warranties for a term of one year for installation work performed under its contracts. Warranties for equipment sold to customers are provided by the original equipment manufacturers. For both Power Drives and XL Grid solutions, the Company accrues the estimated cost of product warranties for unclaimed charges based on historical experiences and expected results. Should product failure rates and material usage costs differ from these estimated revisions to the estimated warranty liability are required. The Company periodically assesses the adequacy of its recorded product warranty liabilities and adjusts the balances as required. Warranty expense is recorded as a component of cost of product revenue in the statements of operations.
Income taxes	Income taxes: Uncertain tax positions taken or expected to be taken in a tax return are accounted for using the more likely than not threshold for financial statement recognition and measurement. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. For the years ended December 31, 2021, 2020 and 2019, there were no uncertain tax position taken or expected to be taken in the Company’s tax returns. In the normal course of business, the Company is subject to regular audits by U.S. federal and state and local tax authorities. With few exceptions, the Company is no longer subject to federal, state or local tax examinations by tax authorities in its major jurisdictions for tax years before 2018. However, net operating loss carryforwards remain subject to examination to the extent they are carried forward and impact a year that is open to examination by tax authorities. The Company did not recognize any tax related interest or penalties in the accompanying consolidated financial statements, but would record any such interest and penalties as a component of the provision for income taxes.
Share-based compensation	Share-based compensation: Stock Options The Company uses the Black-Scholes option pricing model to determine the fair value of stock-based awards, and recognizes the compensation cost on a straight line basis over the requisite service period of the awards for employee, which is typically the four-year vesting period of the award, and effective contract period specified in the award agreement for non-employee. The fair value of common stock is determined based on the closing price of the Company’s common stock on the New York Stock Exchange at each award grant date. The determination of the fair value of share-based payment awards utilizing the Black-Scholes model is affected by the stock price and a number of assumptions, including expected volatility, expected life, risk- free interest rate and expected dividends. The Company does not have a history of trading in its common stock as it was not a public company until December 21, 2020, and as such volatility was estimated using historical volatilities of comparable public entities. The expected life of the awards is estimated based on a simplified method, which uses the average of the vesting term and the original contractual term. The risk-free interest rate assumption is based on observed interest rates appropriate for the expected life of the awards. The dividend yield assumption is based on history and expectation of paying no dividends. Forfeitures are accounted for as they occur. The fair value of stock options issued for the years ended December 31, 2021, 2020, and 2019 was measured with the following assumptions: 2021 2020 2019 Expected volatility 78.1 – 88.2 % 79.6 – 90.5 % 70.0 % Expected term (in years) 6.25 6.2 – 10 6.1 – 10 Risk-free interest rate 0.1 – 1.3 % 0.3 – 1.6 % 1.4 – 3.0 % Expected dividend yield 0.0 % 0.0 % 0.0 % Restricted Stock Units Restricted stock units generally vest over the requisite service periods (vesting on a straight–line basis). The fair value of a restricted stock unit award is equal to the fair market value of a share of the Company’s Common stock on the grant date. The Company accounts for the forfeiture of equity awards as they occur.
Warrant Liabilities	Warrant Liabilities:
Research and development expense	Research and development expense:
Net income (loss) per share	Net income (loss) per share:
Related parties	Related parties:
Recent accounting pronouncements issued and adopted	Recent accounting pronouncements issued and adopted: In February 2016, the Financial Accounting Standards Board (“FASB”) issued a new Accounting Standards Update (“ASU”) , Accounting Standards Codification Topic 842, Leases (“ASC 842”), related to leases to increase transparency and comparability among organizations by requiring the recognition of right-of-use (“ROU”) assets and lease liabilities on the balance sheet. Most significant among the changes in the standard is the recognition of ROU assets and lease liabilities by lessees for those leases classified as operating leases under previous U.S. GAAP. Under the new standard, disclosures are required to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The Company adopted ASC 842 effective January 1, 2021 and as a result, the Company recorded a ROU asset and lease liability within its consolidated financial statements (See Note 12). In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses of Financial Instruments

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of reconciliation of cash, cash equivalents, and restricted cash	As of December 31, 2021 2020 Cash and cash equivalents $ 351,676 $ 329,641 Restricted cash 150 150 Total cash, cash equivalents, and restricted cash $ 351,826 $ 329,791
Schedule of property and equipment, net	Equipment 5 years Furniture and fixtures 3 years Computer and related equipment 2 years Software 2 years Vehicles 5 years Leasehold improvements Lesser of useful life of the asset or remaining life of the lease
Schedule of fair value of stock options issued	2021 2020 2019 Expected volatility 78.1 – 88.2 % 79.6 – 90.5 % 70.0 % Expected term (in years) 6.25 6.2 – 10 6.1 – 10 Risk-free interest rate 0.1 – 1.3 % 0.3 – 1.6 % 1.4 – 3.0 % Expected dividend yield 0.0 % 0.0 % 0.0 %

Merger with Pivotal Investmen_2

Merger with Pivotal Investment Corporation II (Tables)	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Schedule of reconciles the elements of the Business Combination	Cash – Pivotal’s trust and cash (net of redemption) $ 231,975 Cash – PIPE 150,000 Less: transaction costs and advisory fees paid (29,915 ) Net Business Combination and PIPE financing $ 352,060

Business Combination (Tables)

Business Combination (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Schedule of purchase price consideration	Cash $ 8,000 Working capital adjustments 496 Fair value of 231,002 shares issued at closing 1,439 Fair value of the earnout 1,000 Portion of deferred obligation to issue shares of common stock 1,526 Total consideration 12,461 Less the fair value of assets acquired less liabilities assumed (4,344 ) Goodwill $ 8,117
Schedule of fair values of the assets acquired and liabilities assumed by major class	Amount Cash $ 308 Accounts receivable 3,585 Inventory, net 1,282 Prepaid expenses and other current assets 100 Property and equipment, net 173 Intangible assets, net 1,560 Right-of-use asset 145 Goodwill 8,117 Other assets 12 Accounts payable (1,096 ) Lease liability, current (56 ) Accrued expenses and other current liabilities (1,297 ) Deferred revenue (283 ) Lease liability, non-current (89 ) Total purchase consideration $ 12,461
Schedule of supplemental disclosure of pro forma information	2021 2020 2019 Revenues $ 23,349 $ 38,230 $ 27,137 Net (loss) income $ 29,617 $ (59,216 ) $ (13,476 ) Per share amounts: Net (loss) income per share – basic $ 0.21 $ (0.70 ) $ (0.17 ) Net loss per share - diluted $ 0.20 $ (0.70 ) $ (0.17 )

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of disaggregation of revenue	2021 2020 2019 Revenue from the sale of Power Drives: Revenue direct to customers $ 1,373 $ 4,013 $ 3,263 Revenue through channel partners 1,466 16,325 3,952 Revenue from the sale of XL Grid solutions – which are sold direct to customers 12,761 - - Total revenue $ 15,600 $ 20,338 $ 7,215
Schedule of accrued warranty liability	2021 2020 Balance at the beginning of the period $ 1,735 $ 1,009 Acquisition date accrual for World Energy acquisition 25 - Accrual for warranties issued 346 912 Accrual of additional warranty obligations 965 - Warranty fulfillment charges (524 ) (186 ) Balance at the end of the period $ 2,547 $ 1,735

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment	As of December 31, 2021 2020 Equipment $ 1,437 $ 647 Furniture and fixtures 222 91 Computers 412 30 Software 500 359 Vehicles 902 622 Leasehold improvements 267 170 XL Grid projects not yet in service 1,593 - 5,333 1,919 Less accumulated depreciation (1,838 ) (1,340 ) Property and equipment, net $ 3,495 $ 579

Intangibles (Tables)

Intangibles (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Sehedule of annual aggregate amortization expense	Year ending December 31: 2022 986 2023 682 2024 195 Total amortization $ 1,863

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Accrued Expenses and Other Current Liabilities [Abstract]
Schedule of accrued expenses and other current liabilities	2021 2020 Accrued warranty costs $ 2,548 $ 1,735 Accrued compensation and related benefits 2,254 1,001 Contingent purchase price consideration – Quantum 1,950 926 Deferred purchase price consideration – World Energy 278 - Accreted contingent compensation to sellers – World Energy 1,000 - Professional fees 949 723 Accrued settlements 494 Accrued expenses, other 2,383 216 $ 11,856 $ 4,601

ROU Assets and Lease Liabilit_2

ROU Assets and Lease Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Regulatory Assets and Liabilities Disclosure [Abstract]
Schedule of office space and R&D and manufacturing facilities	December 31, January 1, December 31, Operating leases: Right-of-use assets $ 3,443 $ 3,481 $ – Lease liability, current 451 469 – Lease liability, non-current 3,056 3,012 – Finance leases: Right-of-use assets 1,121 897 – Lease liability, current 449 265 – Lease liability, non-current 543 632 –
Schedule of other information related to leases	For the Year Ended 2021 Other information: Operating lease cost $ 855 As of 2021 Operating cash flows from operating leases $ 791 Weighted-average remaining lease term – operating leases (in months) 82.7 Weighted-average discount rate – operating leases 9.7 %
Schedule of annual minimum lease payments of our operating lease liabilities	For The Years Ending December 31, 2022 770 2023 730 2024 694 2025 709 2026 555 Thereafter 1,416 Total future minimum lease payments, undiscounted 4,874 Less: imputed interest (1,367 ) Present value of future minimum lease payments $ 3,507

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of carrying value of debt	As of December 31, 2021 2020 Vehicle financing agreements $ 99 $ 208 Total debt obligations, net of deferred financing costs 99 208 Less: current portion of debt 78 110 Debt – net of current portion $ 21 $ 98

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of fair values private warrants were valued using a black-scholes model	Mark-to-Market Measurement at Mark-to-Market Measurement at December 31, December 31, Input 2021 2020 Risk-free rate 1.111 % 0.36 % Remaining term in years 3.98 4.98 Expected volatility 88.77 % 95.4 % Exercise price $ 11.50 $ 11.50 Fair value of common stock $ 3.31 $ 23.73
Schedule of assets and liabilities which are measured at fair value on a recurring basis	Fair Value Measurements as of Level I Level II Level III Total Asset: Investment in eNow Convertible Note $ - $ - $ - $ - Liability: Private Warrants $ - $ - $ 5,404 $ 5,404 Contingent consideration – Quantum $ - $ - $ 1,950 $ 1,950 Earnout – World Energy $ - $ - $ 1,000 $ 1,000 Fair value of obligation to issue shares of common stock to sellers of World Energy $ - $ - $ 541 $ 541 Fair Value Measurements as of Level I Level II Level III Total Liability: Public Warrants $ 62,100 $ - $ - $ 62,100 Private Warrants $ - $ - $ 81,195 $ 81,195 Contingent consideration – (Quantum) $ - $ - $ 1,849 $ 1,849
Schedule of roll forward of the company's level 3 instruments	For the Years Ended Asset Liability Balance, January 1, 2020 $ - $ 2,852 Reduce derivative liability for extinguishment of convertible notes payable - (1,349 ) Increase derivative liability for issuance of convertible notes payable - 5,637 Private Placement Warrants assumed in connection with the Business Combination - 65,193 Fair value adjustments- Derivatives - 2,889 Fair value adjustments- Contingent consideration - 796 Fair value adjustments- Private Placement Warrants - 16,002 Reduce derivative liability for conversion and repayment of convertible notes - (8,526 ) Reduce contingent consideration for cash payment of a portion of obligation - (450 ) Balance, December 31, 2020 - 83,044 Obligation to issue shares of common stock to sellers of World Energy - 1,526 Fair value adjustment – Quantum contingent consideration - 101 Fair value adjustments – Warrant liability - (75,790 ) Fair value adjustments – World Energy - (565 ) Partial settlement of World Energy contingent consideration (421 ) Purchase of eNow Convertible Note at fair value 3,000 - Reserve for investment in convertible note (3,000 ) - Earnout – World Energy - 1,000 Balance, December 31, 2021 $ - $ 8,895

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Schedule of common stock are reserved for future issuance	Warrants issued and outstanding 4,239,450 Restricted stock units issued and outstanding 606,638 Stock options issued and outstanding 9,737,292 Authorized for future grant of equity instruments under 2020 Equity Incentive Plan 11,003,180 Total 25,586,560

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2021
Warrants [Abstract]
Schedule of warrant activity	Weighted Warrants Shares Exercise Outstanding at January 1, 2020 5,091,970 $ 0.26 Issued 177,229 0.70 Exercised (5,020,082 ) 0.34 Outstanding at January 1, 2021 249,117 $ 0.76 Issued - - Exercised (243,000 ) 0.76 Outstanding at December 31, 2021 6,117 $ 0.76 Exercisable at December 31, 2021 6,117 $ 0.76

Share-Based Compensation Expe_2

Share-Based Compensation Expense (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of stock option award activity	Options Shares Weighted Weighted Outstanding at December 31, 2019 10,087,296 0.25 7.4 Granted 2,738,912 1.76 Exercised (488,860 ) 0.24 Cancelled or forfeited (1,362,124 ) 0.74 Outstanding at December 31, 2020 10,975,224 $ 0.57 7.6 Granted 1,232,844 6.89 Exercised (1,032,819 ) 0.22 Cancelled or forfeited (1,437,957 ) 0.66 Outstanding at December 31, 2021 9,737,292 $ 1.40 7.2 Exercisable at December 31, 2021 7,380,232 $ 0.47 6.9
Schedule of fair value of restricted stock awards	Number of Shares Weighted Average Grant Date Fair Value Per Share Non-vested, at December 31, 2019 446,332 0.24 Granted 25,309 9.21 Vested (25,309 ) 9.21 Non-vested, at December 31, 2020 446,332 $ 0.24 Granted - - Vested - - Cancelled or forfeited - Non-vested, at December 31, 2021 446,332 $ 0.24 Number of Weighted Non-vested, at beginning of period - $ - Granted 651,326 6.38 Vested (13,524 ) 14.17 Cancelled or forfeited (33,369 ) 8.92 Non-vested, at end of period 604,433 $ 6.06

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of net deferred income tax assets	2021 2020 2019 Deferred tax assets (liabilities): Net operating loss carryforwards $ 29,985 $ 20,898 $ 15,239 Tax credit carryforwards 1,840 1,341 1,341 Reserves 1,258 456 308 Share-based compensation 730 172 308 Allowance for impairment of eNow Convertible Note 701 - - Depreciation and amortization 229 (54 ) (16 ) Other 185 89 91 Total deferred tax assets, net 34,928 22,902 17,271 Less valuation allowance (34,928 ) (22,902 ) (17,271 ) Net deferred tax assets (liabilities) - - -
Schedule of the provision for income taxes	For the Years Ended 2021 2020 U.S. federal statutory rate 21.0 % (21.0 )% State taxes, net of federal benefit 2.4 % (4.4 )% Change in fair value of warrant liability (73.6 )% 15.9 % Option and RSU expense 4.5 % 0.3 % Other 0.7 % (0.3 )% True-up to prior years return 3.2 % 0.2 % Change in valuation allowance 41.8 % 9.3 % Effective tax rate - % - %

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Schedule of future minimum lease payments	Future minimum lease payments for this lease are as follows: 2022 156 Total $ 156

Net (Loss) Income Per Share (Ta

Net (Loss) Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of numerator and denominator used to calculate basic earnings per share and diluted earnings per share	Years Ended December 31, 2021 2020 2019 Numerator: Net income (loss) $ 28,790 $ (60,606 ) $ (14,901 ) Denominator: Weighted average shares basic 138,457,416 84,565,448 79,823,065 Dilutive effect of option, warrants and restricted stock units 10,052,935 - - Weighted average shares outstanding, basic and diluted 148,510,351 84,565,448 79,823,065 Net income (loss) per share, basic $ 0.21 $ (0.72 ) $ (0.19 ) Net income (loss) per share, diluted $ 0.19 $ (0.72 ) $ (0.19 )
Schedule of number of shares underlying outstanding dilutive securities	Years Ended December 31, 2021 2020 2019 Stock options 361,292 10,975,222 10,087,294 Private Warrants 4,233,333 11,900,000 - XL Legacy Warrants - 249,117 5,849,164 Total 4,594,625 23,124,339 15,936,458

Organization and Description _2

Organization and Description of Business (Details)	May 17, 2021	Dec. 31, 2021
Organization and Description of Business (Details) [Line Items]
Business combination, description		XL Fleet has over 4,450 electrified powertrain systems sold and driven over 181 million miles by over 245 fleets, as of December 31, 2021.
World Energy Efficiency Services, LLC [Member]
Organization and Description of Business (Details) [Line Items]
Membership interests, percentage	100.00%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Summary of Significant Accounting Policies (Details) [Line Items]
Number of operating segment	1
Cash in excess	$ 250,000	$ 250,000
Restricted cash held	$ 150,000	$ 150,000
Estimated useful lives	4 years
Warrant term	1 year
Accounts Receivable [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Number of customers	2	1
Allowance of doubtful accounts	$ 148	$ 0
Equipment [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Estimated useful lives	5 years
Warrant term	3 years
Inventories [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Inventory reserve for obsolescence	$ 2,863	$ 58
One customers [Member] | Accounts Receivable [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Concentration of credit risk, percentage	74.00%	82.00%
Two customers [Member] | Accounts Receivable [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Concentration of credit risk, percentage	11.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - Schedule of reconciliation of cash, cash equivalents, and restricted cash - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cash, cash equivalents, and restricted cash [Abstract]
Cash and cash equivalents	$ 351,676	$ 329,641
Restricted cash	150	150
Total cash, cash equivalents, and restricted cash	$ 351,826	$ 329,791

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Details) - Schedule of property and equipment, net	12 Months Ended
	Dec. 31, 2021
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	4 years
Furniture and fixtures [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	3 years
Computer and related equipment [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	2 years
Software [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	2 years
Vehicles [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	5 years
Leasehold improvements [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	Lesser of useful life of the asset or remaining life of the lease
Equipment [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Lesser of useful life of the asset or remaining life of the lease	5 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Details) - Schedule of fair value of stock options issued	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies (Details) - Schedule of fair value of stock options issued [Line Items]
Expected volatility			70.00%
Expected term (in years)	6 years 3 months
Expected dividend yield	0.00%	0.00%	0.00%
Minimum [Member]
Summary of Significant Accounting Policies (Details) - Schedule of fair value of stock options issued [Line Items]
Expected volatility	78.10%	79.60%
Expected term (in years)		6 years 2 months 12 days	6 years 1 month 6 days
Risk-free interest rate	0.10%	0.30%	1.40%
Maximum [Member]
Summary of Significant Accounting Policies (Details) - Schedule of fair value of stock options issued [Line Items]
Expected volatility	88.20%	90.50%
Expected term (in years)		10 years	10 years
Risk-free interest rate	1.30%	1.60%	3.00%

Merger with Pivotal Investmen_3

Merger with Pivotal Investment Corporation II (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Exchange ratio, shares	$ 0.7571895
Common stock, par value	$ 0.0001	$ 0.0001
Aggregate of common stock, shares (in Shares)	1,715,918
Aggregate purchase price (in Dollars)	$ 47,162
Common stock, shares authorized (in Shares)	350,000,000	350,000,000
Aggregate principal amount (in Dollars)	$ 11,250,000
XL owned [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Fully-diluted common stock, percentage	75.20%
Merger owned [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Fully-diluted common stock, percentage	24.80%
Subscription Agreement [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Purchase price	$ 10
Aggregate purchase price (in Dollars)	$ 150,000,000
Private Placement Warrants [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Purchase of common stock, shares (in Shares)	4,233,333
Exercise price	$ 11.5
Public Warrants [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Purchase of common stock, shares (in Shares)	7,666,667
Exercise price	$ 11.5
Pivotal Class A Common Stock [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Common stock, par value	$ 0.0001
Common stock, shares authorized (in Shares)	350,000,000
Pivotal Class B Common Stock [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Common stock, par value	$ 0.0001
PIPE Shares [Member]
Merger with Pivotal Investment Corporation II (Details) [Line Items]
Aggregate of common stock, shares (in Shares)	15,000,000

Merger with Pivotal Investmen_4

Merger with Pivotal Investment Corporation II (Details) - Schedule of reconciles the elements of the Business Combination $ in Thousands	Dec. 31, 2020USD ($)
Schedule of reconciles the elements of the Business Combination [Abstract]
Cash – Pivotal’s trust and cash (net of redemption)	$ 231,975
Cash – PIPE	150,000
Less: transaction costs and advisory fees paid	(29,915)
Net Business Combination and PIPE financing	$ 352,060

Business Combination (Details)

Business Combination (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 17, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Combination (Details) [Line Items]
Cash		$ 308
Common stock issued shares (in Shares)		448,050
Selling, general and administration expense		$ 1,049
Loan amount		507
Acquired intangible assets		1,560
Non-recurring merger expenses		498
Interest expense		$ 37	$ 94	$ 99
Business Combination [Member]
Business Combination (Details) [Line Items]
Business combination consideration, Description		The total purchase price consideration, as adjusted, is $12,461 for the acquisition of World Energy. During the year ended December 31, 2021, the Company remitted to the sellers of World Energy additional cash of $76 in connection with the finalization of working capital adjustments. The as-adjusted purchase price consisted of the following components: Cash of $8,496, as adjusted, consisting of the contractual purchase price of $8,000, plus working capital adjustments of an aggregate of $496.  ●The closing date issuance of 231,002 shares of the Company’s common stock, valued at the closing price of $6.23 per share as of May 17, 2021, for a total share fair value upon issuance of $1,439;   ●An obligation to issue 244,956 shares of the Company’s common stock to certain of the sellers and their advisors of World Energy, in three equal installments on the sixth, twenty-fourth and the thirtieth monthly anniversaries of the closing date. The closing date fair value was recorded at an aggregate amount of $1,526;  ●An obligation to pay in cash an earnout of $1,000 upon World Energy’s achievement for the calendar year 2021 of minimum annual revenues of $19,500. The payment of the earnout is due within 30 days following the completion of the audit of XL Fleet’s financial statements for the fiscal year ending December 31, 2021. World Energy met the revenue requirements and as such, the Company expects to pay the $1,000 earnout shortly after the filing of this annual report on Form 10-K.
Shares issued (in Shares)	231,002

Business Combination (Details)

Business Combination (Details) - Schedule of purchase price consideration - Purchase Price Consideration [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Condensed Financial Statements, Captions [Line Items]
Cash	$ 8,000
Working capital adjustments	496
Fair value of 231,002 shares issued at closing	1,439
Fair value of the earnout	1,000
Portion of deferred obligation to issue shares of common stock	1,526
Total consideration	12,461
Less the fair value of assets acquired less liabilities assumed	(4,344)
Goodwill	$ 8,117

Business Combination (Details_2

Business Combination (Details) - Schedule of purchase price consideration (Parentheticals)	12 Months Ended
	Dec. 31, 2021shares
Purchase Price Consideration [Member]
Condensed Financial Statements, Captions [Line Items]
Fair value shares issued	231,002

Business Combination (Details_3

Business Combination (Details) - Schedule of fair values of the assets acquired and liabilities assumed by major class - Purchase Price Consideration [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Business Combination (Details) - Schedule of fair values of the assets acquired and liabilities assumed by major class [Line Items]
Cash	$ 308
Accounts receivable	3,585
Inventory, net	1,282
Prepaid expenses and other current assets	100
Property and equipment, net	173
Intangible assets, net	1,560
Right-of-use asset	145
Goodwill	8,117
Other assets	12
Accounts payable	(1,096)
Lease liability, current	(56)
Accrued expenses and other current liabilities	(1,297)
Deferred revenue	(283)
Lease liability, non-current	(89)
Total purchase consideration	$ 12,461

Business Combination (Details_4

Business Combination (Details) - Schedule of supplemental disclosure of pro forma information - World Energy [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Combination (Details) - Schedule of supplemental disclosure of pro forma information [Line Items]
Revenues	$ 23,349	$ 38,230	$ 27,137
Net (loss) income	$ 29,617	$ (59,216)	$ (13,476)
Per share amounts: Net (loss) income per share – basic	$ 0.21	$ (0.7)	$ (0.17)
Net loss per share - diluted	$ 0.2	$ (0.7)	$ (0.17)

Settlement of Contingent Cons_2

Settlement of Contingent Consideration Quantum (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2022	Dec. 31, 2020
Settlement of Contingent Consideration Quantum (Details) [Line Items]
Cash payment paid		$ 450
Second Milestone [Member] | Subsequent Event [Member]
Settlement of Contingent Consideration Quantum (Details) [Line Items]
Paid cash consideration	$ 475
Shares of common stock (in Shares)	50,000
Third Milestone [Member] | Subsequent Event [Member]
Settlement of Contingent Consideration Quantum (Details) [Line Items]
Paid cash consideration	$ 475
Shares of common stock (in Shares)	50,000

Revenue (Details)

Revenue (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 237,000	$ 305,000	$ 133,000
Recognized revenue	$ 128,000
Description of sales commission	Sales commissions paid to internal sales personnel, as well as associated payroll taxes and retirement plan contributions (together, sales commissions and associated costs) that are incremental to the acquisition of customer contracts, are capitalized as contract acquisition cost on the balance sheet when the period of benefit is determined to be greater than one year. In instances where an extended warranty is sold, the period of benefit would extend beyond 12 months and therefore, the practical expedient would not be met for those contracts and require capitalization of the related costs to obtain those contracts.
Total commission expense	$ 834,000	$ 105,000	$ 226,000
Warranty of manufactured products, description	In general, for the sales of Power Drives, manufactured products are warranted for the shorter of three years or 75,000 miles against defects in material and workmanship when properly used for their intended purpose, installed correctly and appropriately maintained.
Projects warranty term	1 year
Warranty charges	$ 965

Revenue (Details) - Schedule of

Revenue (Details) - Schedule of disaggregation of revenue - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue direct to customers [Member]
Revenue from the sale of Power Drives:
Total revenue	$ 1,373	$ 4,013	$ 3,263
Revenue through channel partners [Member]
Revenue from the sale of Power Drives:
Total revenue	1,466	16,325	3,952
Revenue from the sale of XL Grid solutions – which are sold direct to customers [Member]
Revenue from the sale of Power Drives:
Total revenue	12,761
Total Revenue [Member]
Revenue from the sale of Power Drives:
Total revenue	$ 15,600	$ 20,338	$ 7,215

Revenue (Details) - Schedule _2

Revenue (Details) - Schedule of accrued warranty liability - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of accrued warranty liability [Abstract]
Balance at the beginning of the period	$ 1,735	$ 1,009
Acquisition date accrual for World Energy acquisition	25
Accrual for warranties issued	346	912
Accrual of additional warranty obligations	965
Warranty fulfillment charges	(524)	(186)
Balance at the end of the period	$ 2,547	$ 1,735

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 653	$ 406	$ 265

Property and Equipment (Detai_2

Property and Equipment (Details) - Schedule of property, plant and equipment - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 5,333	$ 1,919
Less accumulated depreciation	(1,838)	(1,340)
Property and equipment, net	3,495	579
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	1,437	647
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	222	91
Computers [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	412	30
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	500	359
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	902	622
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	267	170
XL Grid projects not yet in service [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 1,593

Intangibles (Details)

Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Intangibles (Details) [Line Items]
Amortized over useful life	3 years
Accumulated amortization	$ 325
Acquisition costs	1,560
Amortization expense	791	$ 216	$ 72
Developed Technology [Member]
Intangibles (Details) [Line Items]
Intangible assets gross	$ 863
Amortized over useful life	4 years
Accumulated amortization	$ 485
Sponsorship agreement [Member]
Intangibles (Details) [Line Items]
Intangible assets gross	$ 500
Amortized over useful life	1 year
Accumulated amortization	$ 250

Intangibles (Details) - Schedul

Intangibles (Details) - Schedule of annual aggregate amortization expense $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Schedule of annual aggregate amortization expense [Abstract]
2022	$ 986
2023	682
2024	195
Total amortization	$ 1,863

Purchase of Convertible Note (D

Purchase of Convertible Note (Details) - USD ($) $ in Thousands	Jul. 15, 2021	Dec. 31, 2021
Purchase of Convertible Note [Abstract]
Investment of solar and battery power systems	$ 3,000
Principal amount	$ 3,000
Interest rate	8.00%
Convertible note was fully impaired charge		$ 3,000

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - Schedule of accrued expenses and other current liabilities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of accrued expenses and other current liabilities [Abstract]
Accrued warranty costs	$ 2,548	$ 1,735
Accrued compensation and related benefits	2,254	1,001
Contingent purchase price consideration – Quantum	1,950	926
Deferred purchase price consideration – World Energy	278
Accreted contingent compensation to sellers – World Energy	1,000
Professional fees	949	723
Accrued settlements	494
Accrued expenses, other	2,383	216
Total	$ 11,856	$ 4,601

New Markets Tax Credit Financ_2

New Markets Tax Credit Financing (Details) - USD ($) $ in Thousands	Jan. 14, 2022	Mar. 04, 2015	Dec. 31, 2021	Dec. 31, 2020
New Markets Tax Credit Financing (Details) [Line Items]
Federal income taxes, percentage		39.00%
Loan amount			$ 10,454
State income taxes, percentage			2.40%	(4.40%)
Unamortized debt issuance costs			$ 20	$ 91
Description of transaction			The NMTC is subject to 100% recapture for a period of seven years as provided in the Internal Revenue Code.
Loans receivable			$ 10,500
Loan payable			15,000
Net proceeds received			4,995
Amortized of debt issuance costs			$ 72	$ 78
Subsequent Event [Member]
New Markets Tax Credit Financing (Details) [Line Items]
Note receivable	$ 15,000
Payment of the notes receivable	10,500
Gain on forgiveness of debt	$ 4,500
XL Hybrid Quincy, LLC [Member]
New Markets Tax Credit Financing (Details) [Line Items]
Maturity date			Mar. 4, 2045
Ownership interest rate, percentage			1.15%
Investment Funds [Member]
New Markets Tax Credit Financing (Details) [Line Items]
Federal income taxes, percentage			1.51%
Federal income taxes			$ 6,455
State income taxes			$ 3,999
State income taxes, percentage			1.53%
Equity investment amount			$ 4,995
Principal payments term			7 years
Maturity date			Dec. 31, 2044
Loaned combined funds			$ 15,000
Unamortized debt issuance costs			$ 546

ROU Assets and Lease Liabilit_3

ROU Assets and Lease Liabilities (Details) $ in Thousands	Jan. 01, 2021USD ($)
Regulatory Assets and Liabilities Disclosure [Abstract]
Operating lease, right-of-use asset	$ 3,481
Operating lease liabilities	3,481
Finance lease, right-of-use asset	897
Finance lease liabilities	$ 897

ROU Assets and Lease Liabilit_4

ROU Assets and Lease Liabilities (Details) - Schedule of office space and R&D and manufacturing facilities - Office Space and R&D and Manufacturing Facilities [Member] - USD ($) $ in Thousands	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Operating leases:
Right-of-use assets	$ 3,443	$ 3,481
Lease liability, current	451	469
Lease liability, non-current	3,056	3,012
Finance leases:
Right-of-use assets	1,121	897
Lease liability, current	449	265
Lease liability, non-current	$ 543	$ 632

ROU Assets and Lease Liabilit_5

ROU Assets and Lease Liabilities (Details) - Schedule of other information related to leases $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Other information:
Operating lease cost	$ 855
Operating cash flows from operating leases	$ 791
Weighted-average remaining lease term – operating leases (in months)	82 months 21 days
Weighted-average discount rate – operating leases	9.70%

ROU Assets and Lease Liabilit_6

ROU Assets and Lease Liabilities (Details) - Schedule of annual minimum lease payments of our operating lease liabilities $ in Thousands	Dec. 31, 2021USD ($)
Schedule of annual minimum lease payments of our operating lease liabilities [Abstract]
2022	$ 770
2023	730
2024	694
2025	709
2026	555
Thereafter	1,416
Total future minimum lease payments, undiscounted	4,874
Less: imputed interest	(1,367)
Present value of future minimum lease payments	$ 3,507

Note Payable (Details)

Note Payable (Details) $ in Thousands	1 Months Ended
	Mar. 31, 2021USD ($)
PPP Note [Member]
Note Payable (Details) [Line Items]
Principal amount	$ 507

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 21, 2020	Jan. 31, 2020
Debt (Details) [Line Items]
Description of revolving line of credit	The revolving line of credit bore interest at a floating per annum rate equal to the greater of (i) the prime rate plus 4.50% or (ii) a fixed rate of 7.75%. On December 23, 2020, the revolver was repaid in full.
Additional convertible subordinated debt					$ 13,000
Loss on extinguishment		$ (1,038)
Interest expense	$ 37	94	$ 99
Debt [Member]
Debt (Details) [Line Items]
Loss on extinguishment		$ 1,038
Vehicle financing agreements [Member]
Debt (Details) [Line Items]
Description of debt	The Company has entered into several vehicle financing agreements with various lenders with maturities ranging from 2020 to 2025. Interest rates on these agreements range from 2.95% to 10.00%. Each agreement is collateralized by the equipment purchased.
Convertible Notes Payable [Member]
Debt (Details) [Line Items]
Description of convertible notes payable		the Company issued subordinated convertible promissory notes in the amount of $8,100. The notes mature at the earlier of (i) February 6, 2021 or (ii) the date of a change of control as defined in the note agreements. Upon a change of control, the Company is required to repay all outstanding principal and interest and a 100% premium on the outstanding principal balance of each note. Under the terms of the agreements, upon a qualifying financing event occurring after July 31, 2020, the convertible promissory notes and accrued interest would be convertible at 70% of the price per share paid generally by cash investors in such qualifying financing.
Loss on extinguishment		$ 1,038
face value of convertible notes		$ 10,000
Percentage of convertible notes		10.00%
Interest expense		$ 4,497
Payment of convertible notes				$ 11,250
Issuance of convertible notes (in Shares)				1,715,918
Convertible principal amount				$ 6,850
Accrued interest				$ 1,709

Debt (Details) - Schedule of ca

Debt (Details) - Schedule of carrying value of debt - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of carrying value of debt [Abstract]
Vehicle financing agreements	$ 99	$ 208
Total debt obligations, net of deferred financing costs	99	208
Less: current portion of debt	78	110
Debt – net of current portion	$ 21	$ 98

Fair Value Measurements (Detail

Fair Value Measurements (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)$ / sharesshares
Fair Value Measurements (Details) [Line Items]
Public warrants exercised	7,441,020
Warrant price per share (in Dollars per share) | $ / shares	$ 0.01
Warrant [Member]
Fair Value Measurements (Details) [Line Items]
Issuance of shares	7,441,020
Common Stock [Member]
Fair Value Measurements (Details) [Line Items]
Cash proceeds (in Dollars) | $	$ 85,555
Public warrant shares	225,647

Fair Value Measurements (Deta_2

Fair Value Measurements (Details) - Schedule of fair values private warrants were valued using a black-scholes model - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of fair values private warrants were valued using a black-scholes model [Abstract]
Risk-free rate	1.111%	0.36%
Remaining term in years	3 years 11 months 23 days	4 years 11 months 23 days
Expected volatility	88.77%	95.40%
Exercise price	$ 11.5	$ 11.5
Fair value of common stock	$ 3.31	$ 23.73

Fair Value Measurements (Deta_3

Fair Value Measurements (Details) - Schedule of assets and liabilities which are measured at fair value on a recurring basis - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Asset:
Investment in eNow Convertible Note
Liability:
Public Warrants		$ 62,100
Private Warrants	5,404	81,195
Contingent consideration – Quantum	1,950	1,849
Earnout – World Energy	1,000
Fair value of obligation to issue shares of common stock to sellers of World Energy	541
Level I [Member]
Asset:
Investment in eNow Convertible Note
Liability:
Public Warrants		62,100
Private Warrants
Contingent consideration – Quantum
Earnout – World Energy
Fair value of obligation to issue shares of common stock to sellers of World Energy
Level II [Member]
Asset:
Investment in eNow Convertible Note
Liability:
Public Warrants
Private Warrants
Contingent consideration – Quantum
Earnout – World Energy
Fair value of obligation to issue shares of common stock to sellers of World Energy
Level III [Member]
Asset:
Investment in eNow Convertible Note
Liability:
Public Warrants
Private Warrants	5,404	81,195
Contingent consideration – Quantum	1,950	$ 1,849
Earnout – World Energy	1,000
Fair value of obligation to issue shares of common stock to sellers of World Energy	$ 541

Fair Value Measurements (Deta_4

Fair Value Measurements (Details) - Schedule of roll forward of the company's level 3 instruments - Level 3 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Asset [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance
Reduce derivative liability for extinguishment of convertible notes payable
Increase derivative liability for issuance of convertible notes payable
Private Placement Warrants assumed in connection with the Business Combination
Fair value adjustments- Derivatives
Fair value adjustments- Contingent consideration
Fair value adjustments- Private Placement Warrants
Reduce derivative liability for conversion and repayment of convertible notes
Reduce contingent consideration for cash payment of a portion of obligation
Ending balance
Obligation to issue shares of common stock to sellers of World Energy
Fair value adjustment – Quantum contingent consideration
Fair value adjustments – Warrant liability
Fair value adjustments – World Energy
Partial settlement of World Energy contingent consideration
Purchase of eNow Convertible Note at fair value	3,000
Reserve for investment in convertible note	(3,000)
Earnout – World Energy
Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	83,044	2,852
Reduce derivative liability for extinguishment of convertible notes payable		(1,349)
Increase derivative liability for issuance of convertible notes payable		5,637
Private Placement Warrants assumed in connection with the Business Combination		65,193
Fair value adjustments- Derivatives		2,889
Fair value adjustments- Contingent consideration		796
Fair value adjustments- Private Placement Warrants		16,002
Reduce derivative liability for conversion and repayment of convertible notes		(8,526)
Reduce contingent consideration for cash payment of a portion of obligation		(450)
Ending balance	8,895	$ 83,044
Obligation to issue shares of common stock to sellers of World Energy	1,526
Fair value adjustment – Quantum contingent consideration	101
Fair value adjustments – Warrant liability	(75,790)
Fair value adjustments – World Energy	(565)
Partial settlement of World Energy contingent consideration	(421)
Purchase of eNow Convertible Note at fair value
Reserve for investment in convertible note
Earnout – World Energy	$ 1,000

Stockholders' Equity (Details)

Stockholders' Equity (Details)	Dec. 31, 2021shares
Common Stock [Member]
Stockholders' Equity (Details) [Line Items]
Common stock, shares authorized	350,000,000

Stockholders' Equity (Details)

Stockholders' Equity (Details) - Schedule of common Stock are reserved for future issuance	12 Months Ended
	Dec. 31, 2021shares
Class of Warrant or Right [Line Items]
Total	25,586,560
Warrants issued and outstanding [Member]
Class of Warrant or Right [Line Items]
Total	4,239,450
Restricted stock units issued and outstanding [Member]
Class of Warrant or Right [Line Items]
Total	606,638
Stock options issued and outstanding [Member]
Class of Warrant or Right [Line Items]
Total	9,737,292
Authorized for future grant of equity instruments under 2020 Equity Incentive Plan [Member]
Class of Warrant or Right [Line Items]
Total	11,003,180

Warrants (Details)

Warrants (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Warrants [Abstract]
Common stock shares issued		4,995,584
Cash proceeds		$ 884
Description of warrants	During the year ended December 31, 2021, 243,000 Legacy XL Warrants were exercised, which resulted in the issuance of 233,555 shares of the Company’s common stock, in a cashless exercise.

Warrants (Details) - Schedule o

Warrants (Details) - Schedule of warrant activity - Warrant [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Warrants (Details) - Schedule of warrant activity [Line Items]
Shares, Outstanding, Beginning balance	249,117	5,091,970
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 0.76	$ 0.26
Issued		177,229
Issued		$ 0.7
Exercised	(243,000)	(5,020,082)
Exercised	$ 0.76	$ 0.34
Shares, Outstanding, Ending balance	6,117	249,117
Weighted Average Exercise Price, Outstanding, Ending balance	$ 0.76	$ 0.76
Shares, Exercisable, Ending balance	6,117
Weighted Average Exercise Price, Exercisable, Ending balance	$ 0.76

Share-Based Compensation Expe_3

Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-Based Compensation Expense (Details) [Line Items]
Share-based compensation expense	$ 7,881	$ 978	$ 208
Unrecognized compensation cost	$ 6,423
Weighted-average period	2 years 8 months 12 days
Options issued (in Shares)	1,232,844	2,738,912
Aggregate intrinsic value of stock options outstanding	$ 24,777
Aggregate intrinsic value of stock options exercisable	20,967
Cash received from options exercised	229	$ 114	$ 10
Restricted stock issued	$ 604,433
Minimum [Member]
Share-Based Compensation Expense (Details) [Line Items]
Stock options employees and board members term	1 year
Restricted stock units and board members term	1 year
Maximum [Member]
Share-Based Compensation Expense (Details) [Line Items]
Stock options employees and board members term	4 years
Restricted stock units and board members term	4 years
Common Stock [Member]
Share-Based Compensation Expense (Details) [Line Items]
Restricted stock issued	$ 2,205

Share-Based Compensation Expe_4

Share-Based Compensation Expense (Details) - Schedule of stock option award activity - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of stock option award activity [Abstract]
Shares, Outstanding Beginning balance	10,975,224	10,087,296
Weighted Average Exercise Price, Outstanding Beginning balance	$ 0.57	$ 0.25
Weighted Average Remaining Contractual Term, Beginning balance		7 years 4 months 24 days
Granted, Shares	1,232,844	2,738,912
Granted, Weighted Average Exercise Price	$ 6.89	$ 1.76
Shares, Exercised	(1,032,819)	(488,860)
Weighted Average Exercise Price, Exercised	$ 0.22	$ 0.24
Shares, Cancelled or forfeited	(1,437,957)	(1,362,124)
Weighted Average Exercise Price, Cancelled or forfeited	$ 0.66	$ 0.74
Shares, Outstanding, Ending Balance	9,737,292	10,975,224
Weighted Average Exercise Price, Ending balance	$ 1.4	$ 0.57
Weighted Average Remaining Contractual Term, Ending balance	7 years 2 months 12 days	7 years 7 months 6 days
Shares, Exercisable	7,380,232
Weighted Average Exercise Price, Exercisable	$ 0.47
Weighted Average Remaining Contractual Term, Exercisable	6 years 10 months 24 days

Share-Based Compensation Expe_5

Share-Based Compensation Expense (Details) - Schedule of fair value of restricted stock awards - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Restricted Stock Awards [Member]
Share-Based Compensation Expense (Details) - Schedule of fair value of restricted stock awards [Line Items]
Number of shares, Non-vested, at beginning of period		446,332
Weighted-average grant-date fair value per share, Non-vested, at beginning of period		$ 0.24
Number of shares, Granted		25,309
Weighted-average grant-date fair value per share Granted		$ 9.21
Number of shares, Vested		(25,309)
Weighted-average grant-date fair value per share, Vested		$ 9.21
Number of shares, Cancelled or forfeited
Weighted-average grant-date fair value per share, Cancelled or forfeited
Number of shares, Non-vested, at end of period	446,332
Weighted-average grant-date fair value per share, Non-vested, at end of period	$ 0.24
Restricted Stock Units [Member]
Share-Based Compensation Expense (Details) - Schedule of fair value of restricted stock awards [Line Items]
Number of shares, Non-vested, at beginning of period
Weighted-average grant-date fair value per share, Non-vested, at beginning of period
Number of shares, Granted	651,326
Weighted-average grant-date fair value per share Granted	$ 6.38
Number of shares, Vested	(13,524)
Weighted-average grant-date fair value per share, Vested	$ 14.17
Number of shares, Cancelled or forfeited	(33,369)
Weighted-average grant-date fair value per share, Cancelled or forfeited	$ 8.92
Number of shares, Non-vested, at end of period	604,433
Weighted-average grant-date fair value per share, Non-vested, at end of period	$ 6.06

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Taxes (Details) [Line Items]
Income tax benefit, percentage	50.00%
Federal net operating loss carryforwards	$ 12,026
State net operating loss carryforwards		$ 5,659
Operating loss carryforwards, description	As of December 31, 2021, the Company has federal and state net operating loss carryforwards of approximately $122,000 and $69,000, respectively, approximately $31,300 of the federal net operating loss carryforward will expire at various dates commencing on 2029 and through 2037 and $90,700 were generated between the years ended December 31, 2018 and 2021 and have an indefinite life.
Tax credit carryforward, description	These federal and state tax credits are available to reduce future taxable income and expire at various dates commencing 2026 through 2039.
Federal [Member]
Income Taxes (Details) [Line Items]
Tax credit carryforward	$ 1,452
State [Member]
Income Taxes (Details) [Line Items]
Tax credit carryforward	$ 388

Income Taxes (Details) - Schedu

Income Taxes (Details) - Schedule of net deferred income tax assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets (liabilities):
Net operating loss carryforwards	$ 29,985	$ 20,898	$ 15,239
Tax credit carryforwards	1,840	1,341	1,341
Reserves	1,258	456	308
Share-based compensation	730	172	308
Allowance for impairment of eNow Convertible Note	701
Depreciation and amortization	229	(54)	(16)
Other	185	89	91
Total deferred tax assets, net	34,928	22,902	17,271
Less valuation allowance	$ (34,928)	$ (22,902)	(17,271)
Net deferred tax assets (liabilities)

Income Taxes (Details) - Sche_2

Income Taxes (Details) - Schedule of the provision for income taxes	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of the provision for income taxes [Abstract]
U.S. federal statutory rate	21.00%	(21.00%)
State taxes, net of federal benefit	2.40%	(4.40%)
Change in fair value of warrant liability	(73.60%)	15.90%
Option and RSU expense	4.50%	0.30%
Other	0.70%	(0.30%)
True-up to prior years return	3.20%	0.20%
Change in valuation allowance	41.80%	9.30%
Effective tax rate

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Related Party Transactions [Abstract]
Rent expense	$ 231	$ 235	$ 235

Related Party Transactions (D_2

Related Party Transactions (Details) - Schedule of future minimum lease payments $ in Thousands	Dec. 31, 2021USD ($)
Schedule of future minimum lease payments [Abstract]
2022	$ 156
Total	$ 156

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Mar. 02, 2021	Mar. 01, 2021	Jun. 25, 2021	Sep. 30, 2021	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Incurred costs					$ 700
Sponsor fee					500
Sponsor fee paid			$ 250
Accrued payment					250
Purchase price		$ 4,191
Nonrefundable down payment	$ 780
Received refund down payment					$ 780
Purchase commitments, description				As of December 31, 2021, these purchase obligations consisted an obligation of $2,132 to purchase motors by July 2022 and an open ended commitment of $2,700 to purchase batteries, an obligation of $936 to acquire batteries for hybrid electric vehicle, and an obligation of $748 to buy chip-sensitive items including telematics modules and inverters.

Leadership Transition (Details)

Leadership Transition (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Nov. 20, 2021
Leadership Transition Disclosures [Abstract]
Separation agreement, description		In connection with the separation agreement, the Company agreed to accelerate the vesting of all outstanding stock options by one year, extend the exercise period of the stock options to two years, and pay twelve months of severance.
Incremental value	$ 4,372

Net (Loss) Income Per Share (De

Net (Loss) Income Per Share (Details) - Schedule of numerator and denominator used to calculate basic earnings per share and diluted earnings per share - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income (loss)	$ 28,790	$ (60,606)	$ (14,901)
Denominator:
Weighted average shares basic	138,457,416	84,565,448	79,823,065
Dilutive effect of option, warrants and restricted stock units	$ 10,052,935
Weighted average shares outstanding, basic and diluted	148,510,351	84,565,448	79,823,065
Net income (loss) per share, basic	$ 0.21	$ (0.72)	$ (0.19)
Net income (loss) per share, diluted	$ 0.19	$ (0.72)	$ (0.19)

Net (Loss) Income Per Share (_2

Net (Loss) Income Per Share (Details) - Schedule of number of shares underlying outstanding dilutive securities - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	4,594,625	23,124,339	15,936,458
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	361,292	10,975,222	10,087,294
Private Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	4,233,333	11,900,000
XL Legacy Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total		249,117	5,849,164

Retirement Plan (Details)

Retirement Plan (Details)	12 Months Ended
	Dec. 31, 2021
Retirement Plan (Details) [Line Items]
Deferral rate, percentage	3.00%
Retirement plan, description	The Company provides for safe harbor matching contributions equal to 100% on the first 3% of an employee’s eligible earnings deferred and an additional 50% on the next 2% of an employee’s eligible earnings deferred. Employee elective deferrals and safe harbor matching contributions are 100% vested at all times.
Tax-advantaged basis, description	In connection with the acquisition of World Energy, XL Fleet adopted the World Energy 401(k) plan whose features are the same as those of the XL Fleet 401(k) plan except that (i) Participants are allowed to contribute, subject to IRS limitations on total annual contributions from 1% to 100% of eligible earnings and (ii) the safe harbor non-elective contribution is equal to 3% of employee’s compensation.
Minimum [Member]
Retirement Plan (Details) [Line Items]
Annual contributions, percentage	1.00%
Maximum [Member]
Retirement Plan (Details) [Line Items]
Annual contributions, percentage	90.00%

Subsequent Events (Details)

Subsequent Events (Details)	1 Months Ended
	Feb. 28, 2022
Subsequent Event [Member]
Subsequent Events (Details) [Line Items]
Subsequent event, description	the Company eliminated 51 positions as part of a strategic realignment to narrow its focus and reduce some aspects of the Company’s hybrid offerings. In connection with the elimination of these positions, the Company incurred severance charges totaling $1,251.