HYLIION HOLDINGS CORP., 10-K filed on 2/13/2024
Annual Report
v3.24.0.1
Cover - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Feb. 06, 2024
Jun. 30, 2023
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Current Fiscal Year End Date --12-31    
Document Period End Date Dec. 31, 2023    
Document Transition Report false    
Entity File Number 001-38823    
Entity Registrant Name HYLIION HOLDINGS CORP.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 83-2538002    
Entity Address, Address Line One 1202 BMC Drive    
Entity Address, Address Line Two Suite 100    
Entity Address, City or Town Cedar Park    
Entity Address, State or Province TX    
Entity Address, Postal Zip Code 78613    
City Area Code 833    
Local Phone Number 495-4466    
Title of 12(b) Security Common Stock    
Trading Symbol HYLN    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction false    
Entity Shell Company false    
Entity Public Float     $ 245
Entity Common Stock, Shares Outstanding   183,208,375  
Documents Incorporated by Reference Portions of the registrant’s definitive proxy statement for the 2024 Annual Meeting of Stockholders, to be filed no later than 120 days after the end of the fiscal year to which this Annual Report on Form 10-K relates, are incorporated by reference into Part III of this Annual Report on Form 10-K.    
Amendment Flag false    
Entity Central Index Key 0001759631    
Document Fiscal Year Focus 2023    
Document Fiscal Period Focus FY    
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Audit Information
 12 Months Ended
Dec. 31, 2023
Audit Information [Abstract]  
Auditor Firm ID 248
Auditor Name GRANT THORNTON LLP
Auditor Location Dallas, Texas
v3.24.0.1
CONSOLIDATED BALANCE SHEETS - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Current assets    
Cash and cash equivalents $ 12,881 $ 119,468
Accounts receivable, net 40 1,136
Inventory 0 74
Prepaid expenses and other current assets 18,483 9,795
Short-term investments 150,297 193,740
Total current assets 181,701 324,213
Property and equipment, net 9,987 5,606
Operating lease right-of-use assets 7,070 6,470
Intangible assets, net 0 200
Other assets 1,439 1,686
Long-term investments 128,186 108,568
Total assets 328,383 446,743
Current liabilities    
Accounts payable 4,224 2,800
Current portion of operating lease liabilities 847 347
Accrued expenses and other current liabilities 10,051 11,535
Total current liabilities 15,122 14,682
Operating lease liabilities, net of current portion 6,792 6,972
Other liabilities 203 1,515
Total liabilities 22,117 23,169
Commitments and contingencies (Note 14)
Stockholders’ equity    
Common stock, $0.0001 par value; 250,000,000 shares authorized; 183,071,317 and 179,826,309 shares issued and outstanding at December 31, 2023 and 2022, respectively 18 18
Additional paid-in capital 404,045 397,810
Treasury stock, at cost; 37,062 and no shares as of December 31, 2023 and 2022, respectively (33) 0
(Accumulated deficit) retained earnings (97,764) 25,746
Total stockholders’ equity 306,266 423,574
Total liabilities and stockholders’ equity $ 328,383 $ 446,743
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CONSOLIDATED BALANCE SHEETS (Parentheticals) - $ / shares
Dec. 31, 2023
Dec. 31, 2022
Statement of Financial Position [Abstract]    
Common stock, par value (in dollars per share) $ 0.0001 $ 0.0001
Common stock, shares authorized (in shares) 250,000,000 250,000,000
Common stock, shares issued (in shares) 183,071,317 179,826,309
Common stock, shares outstanding (in shares) 183,071,317 179,826,309
Treasury stock (in shares) 37,062 0
v3.24.0.1
CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Income Statement [Abstract]    
Revenue from Contract with Customer, Product and Service [Extensible Enumeration] Product sales and other Product sales and other
Revenues    
Revenues $ 672 $ 2,106
Cost of revenues    
Cost of revenues 1,716 8,778
Gross loss (1,044) (6,672)
Operating expenses    
Research and development 82,240 110,370
Selling, general and administrative 42,611 41,988
Exit and termination costs 11,474 0
Total operating expenses 136,325 152,358
Loss from operations (137,369) (159,030)
Interest income 13,808 5,724
Gain (loss) on impairment and disposal of assets 1 (19)
Other income (expense), net 50 (32)
Net loss $ (123,510) $ (153,357)
Net loss per share, basic (in dollars per share) $ (0.68) $ (0.87)
Net loss per share, diluted (in dollars per share) $ (0.68) $ (0.87)
Weighted-average shares outstanding, basic (in shares) 181,411,069 175,400,486
Weighted-average shares outstanding, diluted (in shares) 181,411,069 175,400,486
Product sales and other    
Cost of revenues    
Cost of revenues $ 1,716 $ 8,778
v3.24.0.1
CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($)
$ in Thousands
Total
Common Stock
Treasury Stock
Additional Paid-In Capital
(Accumulated Deficit) Retained Earnings
Balance at beginning (in Shares) at Dec. 31, 2021   173,468,979      
Balance at beginning at Dec. 31, 2021 $ 553,915 $ 17 $ 0 $ 374,795 $ 179,103
Balance at beginning of treasury stock (in shares) at Dec. 31, 2021     0    
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Issuance of common stock for acquisition (in shares)   5,500,000      
Issuance of common stock for acquisition 16,115 $ 1   16,114  
Exercise of common stock options and vesting of restricted stock units, net (in shares)   857,330      
Exercise of common stock options and vesting of restricted stock units, net (78)     (78)  
Share-based compensation 6,979     6,979  
Net loss $ (153,357)       (153,357)
Balance at ending (in Shares) at Dec. 31, 2022 179,826,309 179,826,309      
Balance at ending at Dec. 31, 2022 $ 423,574 $ 18 $ 0 397,810 25,746
Balance at ending of treasury stock (in shares) at Dec. 31, 2022 0   0    
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Exercise of common stock options and vesting of restricted stock units, net (in shares)   3,245,008      
Exercise of common stock options and vesting of restricted stock units, net $ 18     18  
Share-based compensation 6,217     6,217  
Repurchase of treasury stock (in shares)     (37,062)    
Repurchase of treasury stock (33)   $ (33)    
Net loss $ (123,510)       (123,510)
Balance at ending (in Shares) at Dec. 31, 2023 183,071,317 183,071,317      
Balance at ending at Dec. 31, 2023 $ 306,266 $ 18 $ (33) $ 404,045 $ (97,764)
Balance at ending of treasury stock (in shares) at Dec. 31, 2023 (37,062)   (37,062)    
v3.24.0.1
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Cash flows from operating activities    
Net loss $ (123,510) $ (153,357)
Adjustments to reconcile net loss to net cash used in operating activities:    
Depreciation and amortization 3,511 1,227
Amortization and accretion of investments, net (2,868) 1,250
Noncash lease expense 1,496 1,244
Inventory write-down 1,139 5,641
(Gain) loss on impairment and disposal of assets (1) 19
Share-based compensation 6,217 6,979
Provision for doubtful accounts 0 114
Acquired in-process research and development (Note 2) 0 28,752
Change in operating assets and liabilities, net of effects of business acquisition:    
Accounts receivable 1,096 (1,180)
Inventory (1,065) (5,601)
Prepaid expenses and other assets 463 (571)
Accounts payable 1,356 (4,660)
Accrued expenses and other liabilities (3,020) 4,571
Operating lease liabilities (1,776) (1,305)
Net cash used in operating activities (116,962) (116,877)
Cash flows from investing activities    
Purchase of property and equipment and other (7,401) (2,885)
Proceeds from sale of property and equipment 2 152
Purchase of in-process research and development 0 (14,428)
Payments for security deposit, net (45) 0
Purchase of investments (189,670) (268,584)
Proceeds from sale and maturity of investments 215,422 263,723
Net cash provided by (used in) investing activities 18,308 (22,022)
Cash flows from financing activities    
Proceeds from exercise of common stock options 257 79
Taxes paid related to net share settlement of equity awards (239) (157)
Repurchase of treasury stock (33) 0
Net cash used in financing activities (15) (78)
Net decrease in cash and cash equivalents and restricted cash (98,669) (138,977)
Cash and cash equivalents and restricted cash, beginning of period 120,133 259,110
Cash and cash equivalents and restricted cash, end of period $ 21,464 $ 120,133
v3.24.0.1
Description of Organization and Business Operations and Basis of Presentation
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Description of Organization and Business Operations and Basis of Presentation
Note 1. Description of Organization and Business Operations and Basis of Presentation
Overview
Hyliion Holdings Corp. is a Delaware corporation headquartered in Cedar Park, Texas, that designs and develops stationary power applications and electric powertrain systems. References to the “Company,” “Hyliion,” “we,” or “us” in this report refer to Hyliion Holdings Corp. and its wholly owned subsidiary, unless expressly indicated or the context otherwise requires.
The Company plans to develop and commercialize a fuel-agnostic generator (the “KARNO generator”) to be used in stationary power applications. The Company believes the KARNO generator is well positioned to address the rising strain on electrical infrastructure, notably from electric vehicles.
The Company announced a strategic review of alternatives for its electric powertrain business on October 10, 2023 citing lower than expected industry adoption of electric trucks, significant increases in component costs, changing regulatory requirements, and uncertainty about its ability to raise additional capital needed for ongoing investment in the business as reason for undertaking this strategic review. On November 7, 2023, the board of directors (the “Board”) determined that the Company would wind down operating the powertrain business. Hyliion intends to retain the technology of the powertrain business technology and will continue to explore potential sales or future use of both the technology and tangible assets from the powertrain business.
Basis of Presentation and Principles of Consolidation
The accompanying consolidated financial statements include the accounts of Hyliion Holdings Corp. and its wholly owned subsidiary. Intercompany transactions and balances have been eliminated upon consolidation. The consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the rules and regulations of the Unites States Securities and Exchange Commission (“SEC”). Any reference in these footnotes to the applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Certain prior period balances have been reclassified to conform to the current period presentation in the consolidated financial statements and the accompanying notes.
These consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities in the normal course of business. The Company is an early-stage growth company and has generated negative cash flows from operating activities since inception. At December 31, 2023, the Company had total equity of $306.3 million, inclusive of cash and cash equivalents of $12.9 million and total investments of $278.5 million. Based on this, the Company has sufficient funds to continue to execute its business strategy for the next twelve months from the issuance date of the financial statements included in this Annual Report on Form 10-K.
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Acquisitions and Disposals
 12 Months Ended
Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]  
Acquisitions and Disposals
Note 2. Acquisitions and Disposals
Disposals
On November 7, 2023, the Board of the Company approved a strategic plan to wind down its powertrain business and preserve technology relating to the powertrain business, to better align its workforce with the Company’s future needs, and to reduce the Company’s operating costs (the “Plan”). As part of the Plan, the Company will continue to focus on commercialization of its KARNO generator technology. Following completion of the Plan, we no longer expect to recognize revenue on products not related to KARNO technology, including the Company’s Hypertruck ERX system (“Hypertruck ERX”) and Hyliion Hybrid system (“Hybrid”). The Company continues to evaluate opportunities to monetize certain of the tangible assets relating to the Business, but no assurances can be provided that any such opportunities will be realized. The Company expects the wind-down to be primarily completed by the end of the Company’s first quarter of fiscal year 2024. We have not accounted for the impacts of the Plan as a discontinued operation through December 31, 2023, and substantial ongoing wind-down activities remain.
The Plan included a reduction of the Company’s workforce by approximately 175 people, or 67%, with some severance agreements that provide for continued services through various dates of the Company’s fiscal year 2024. The Plan is expected to result in total charges and expenses of approximately $20.4 million including: (i) $1.2 million in employee severance and retention payments, (ii) $0.7 million in accelerated non-cash stock-based compensation expense, (iii) $14.5 million in contract termination and other cancellation costs, excluding amounts recoverable from resale of tangible assets, and (iv) $4.0 million in non-cash charges, including accelerated depreciation and amortization. Charges and expenses related to the Plan of $11.5 million were incurred in the Company’s fourth quarter of fiscal year 2023 included in exit and termination costs in the consolidated statements of operations. The remaining $8.9 million in charges and expenses are expected to be incurred in the first quarter of fiscal 2024, excluding amounts recoverable from resale of tangible assets.
The change in total liabilities associated with the Plan, excluding warranty balances in Note 12, is summarized as follows (in millions). These balances are included within accrued expenses and other current liabilities, as presented in Note 11, with the remainder included within accounts payable.
December 31, 2022Charged to ExpenseCosts Paid or SettledDecember 31, 2023
Employee severance and retention$— $1.2 $(0.1)$1.1 
Contract terminations— 8.2 (1.7)6.5 
$— $9.4 $(1.8)$7.6 
The above estimates of the cash expenditures and charges that the Company expects to incur in connection with the Plan, and the timing thereof, are subject to a number of assumptions and actual amounts may differ materially from estimates. In addition, the Company may incur other cash expenditures or charges not currently contemplated due to unanticipated events that may occur, including in connection with the implementation of the Plan or otherwise.
Acquisitions
In September 2022, we acquired certain assets (the “Acquired Asset”) of General Electric Company's GE Additive business (the “Acquisition”) including new hydrogen and fuel agnostic capable generator technology. The Acquisition did not meet the definition of a business combination and was accounted for as an asset acquisition. No goodwill was recognized and payments allocated to in-process research and development (“IPR&D”) were recorded in research and development expense as there was no alternative future use. Total consideration for the Acquisition was $32.3 million comprised of $15.0 million in cash, 5,500,000 shares of common stock valued at $16.1 million on the closing date and $1.2 million in direct transaction costs. $3.6 million was recorded as property and equipment with expected useful lives of primarily five years and $28.8 million was recorded as research and development expense. All assets were valued using level 3 inputs, with property and equipment valued using a market approach and IPR&D valued using an income approach based on Company management’s projections. The cash component of the consideration was recorded in the statement of cash flows and allocated between purchase of property and equipment and purchase of IPR&D under investing activities.
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Summary of Significant Accounting Policies
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies
Note 3. Summary of Significant Accounting Policies
Use of Estimates
The preparation of financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the balance sheet date, as well as reported amounts of expenses during the reporting period. The Company’s most significant estimates and judgments involve inventory, acquisitions, disposals, income taxes, valuation of share-based compensation, and probability-weighted future cash flows associated with long-lived asset impairment reviews. Management bases its estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making
judgments about the carrying values of assets and liabilities. Actual results could differ from those estimates, and such differences could be material to the Company’s consolidated financial statements.
Segment Information
ASC 280, Segment Reporting, defines operating segments as components of an enterprise where discrete financial information is available that is evaluated regularly by the chief operating decision-maker (“CODM”) in deciding how to allocate resources and in assessing performance. The Company operates as a single operating segment. The Company’s CODM is the chief executive officer, who has ultimate responsibility for the operating performance of the Company and the allocation of resources. The CODM uses cash flows as the primary measure to manage the business and does not segment the business for internal reporting or decision making.
Concentration of Supplier Risk
The Company is dependent on certain suppliers, the majority of which are single source suppliers, and the inability of these suppliers to deliver necessary components of the Company’s products in a timely manner at prices, quality levels and volumes that are acceptable, or the Company’s inability to efficiently manage these components from these suppliers, could have a material adverse effect on the Company’s business, prospects, financial condition and operating results.
Cash and Cash Equivalents
The Company considers all highly liquid investments with a maturity date of 90 days or less at the time of purchase to be cash and cash equivalents only if in checking, savings or money market accounts. Cash and cash equivalents include cash held in banks and money market accounts and are carried at cost, which approximates fair value. The Company maintains cash in excess of federally insured limits at financial institutions which it believes are of high credit quality and has not incurred any losses related to these balances to date. The Company believes its credit risk, with respect to these financial institutions to be minimal.
Restricted Cash
The Company provided a supplier with a letter of credit for $7.9 million in the fourth quarter of 2023 to secure the performance of the Company’s obligations to purchase semi-trucks related to the Founders Program, backed by a restricted cash deposit to pay any draws on the letter of credit by the supplier.
The Company has provided its corporate headquarters lessor with a letter of credit for $0.7 million to secure the performance of the Company’s lease obligations, backed by a restricted cash deposit to pay any draws on the letter of credit by the lessor.
Total cash and cash equivalents and restricted cash as presented in the consolidated statements of cash flows is summarized as follows:
December 31, 2023December 31, 2022December 31, 2021
Cash and cash equivalents$12,881 $119,468 $258,445 
Restricted cash included in prepaid expenses and other current assets7,918 — — 
Restricted cash included in other assets665 665 665 
$21,464 $120,133 $259,110 
Accounts Receivable
Accounts receivable are stated at a gross invoice amount, net of an allowance for doubtful accounts. The allowance for doubtful accounts is maintained at a level considered adequate to provide for potential account losses on the balance based on the Company’s evaluation of the anticipated impact of current economic conditions, changes in the character and size of the balance, past and expected future loss experience and other pertinent factors. At December 31, 2023 and 2022, accounts receivable included amounts receivable from customers of $0.0 million and $1.1 million, respectively. At December 31, 2023 and 2022, allowance for doubtful accounts on customer receivables were $0.0 million and $0.1 million, respectively.
The portion of our net accounts receivable from significant customers is summarized as follows:
December 31,
20232022
Customer A— %82 %
Customer C— 12 
— %94 %
Investments
The Company’s investments consist of corporate bonds, U.S. treasury and agency securities, state and local municipal bonds and commercial paper, all of which are classified as held-to-maturity, with a maturity date of 36-months or less at the time of purchase. The Company determines the appropriate classification of investments at the time of purchase and re-evaluates such designation as of each balance sheet date. Investments are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization, along with interest, is included in interest income. The Company uses the specific identification method to determine the cost basis of securities sold.
Investments are impaired when a decline in fair value is judged to be other-than-temporary. The Company evaluates investments for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to other income (expense) and a new cost basis in the investment is established.
Fair Value Measurements
ASC 820, Fair Value Measurements, clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based upon assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820 establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:
Level I: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the Company can access at the measurement date;
Level II: Significant other observable inputs other than level I prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data; and
Level III: Significant unobservable inputs that reflect the Company’s own assumptions about the assumptions that market participants would use in pricing an asset or liability.
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.
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 and restricted cash, accounts receivable, investments, accounts payable and accrued expenses. The carrying value of cash and cash equivalents and restricted cash, accounts receivable, accounts payable and accrued expenses approximate fair value because of the short-term nature of those instruments. The fair value of investments is based on quoted prices for identical or similar instruments in markets that are not active. As a result, investments are classified within Level II of the fair value hierarchy.
Inventories
Inventory is comprised of raw materials, work in process and finished goods and includes the cost of raw materials, freight, direct and indirect labor and allocations of other conversion costs and overhead. Semi-truck inventory is valued using the specific identification cost method and all other inventory is valued using the moving-average cost method. Inventory is stated at the lower of cost or net realizable value. We review our inventory to determine whether its carrying value exceeds the net amount realizable we expect to receive upon the ultimate sale of the inventory. This requires us to determine the estimated
selling price of inventory less the estimated cost to convert the inventory on-hand into a finished product and other costs, which we determined includes the cost of installation and validation, to align with the transfer of control to customers in our revenue policy. Inventory write-downs are first allocated to all other inventory with any residual allocated to semi-truck inventory.
Once inventory is written-down based on a lower of cost or net realizable value analysis, that amount establishes the new carrying value of inventory if written-down at year end, and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established cost basis. Interim impairments are reversed and reassessed at each reporting period.
During the fourth quarter of 2021, we changed from a research and development phase to a production phase for our Hybrid system product. Through December 31, 2023, we have not yet commercialized the KARNO generator. Costs incurred for components acquired prior to our determination of reaching a commercial stage are expensed as research and development costs, resulting in zero cost basis for those components. As a result, moving-average prices for inventory that is capitalized in future periods may be significantly affected by those zero cost items.
Prepaid Expenses and Other Current Assets
Prepaid expenses and other current assets include prepaid insurance, rent and supplies, which are expected to be recognized, received or realized within the next 12 months.
Property and Equipment, Net
Property and equipment, net is stated at cost less accumulated depreciation, or if acquired in a business combination, at allocated fair value at the date of acquisition. Depreciation is calculated using the straight-line method, based upon the following estimated useful lives:
Production machinery and equipment
2 to 7 years
Vehicles
3 to 7 years
Leasehold improvements
shorter of lease term or 7 years
Demo fleet systems
2 to 3 years
Furniture and fixtures3 years
Computers and related equipment
3 to 7 years
Major renewals and 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 consolidated statement of operations as a component of other income (expense). All long-lived assets are located in the United States.
Impairment of Long-Lived Assets
The Company reviews long-lived assets, including property and equipment and intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate that an asset group’s carrying amount may not be recoverable. The Company conducts its long-lived asset impairment analysis in accordance with ASC 360-10, Impairment or Disposal of Long-Lived Assets, which requires the Company to group assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and evaluate the asset group against the sum of the undiscounted future cash flows. If the undiscounted cash flows do not indicate the carrying amount of the asset group is recoverable, an impairment charge is measured as the amount by which the carrying amount of the asset group exceeds its fair value.
As a result of factors including the events surrounding the Plan discussed in Note 2, the Company performed a test of recoverability of its long-lived assets and determined that all long-lived assets were recoverable as of September 30, 2023. As of September 30, 2023, long-lived assets associated with the powertrain business had a recorded amount of $4.2 million and associated probability-weighted estimated future cash flows of $4.4 million. If the Company is unable to sell long-lived assets associated with the powertrain business at a sufficient price, it will record associated impairment charges in future periods. Estimated future cash flows for all other long-lived assets substantially exceeded recorded amounts.
Revenue
The Company follows five steps to recognize revenue from contracts with customers under ASC 606, Revenue from Contracts with Customers, which are:
•Step 1: Identify the contract(s) with a customer;
•Step 2: Identify the performance obligations in the contract;
•Step 3: Determine the transaction price;
•Step 4: Allocate the transaction price to the performance obligations in the contract; and
•Step 5: Recognize revenue when (or as) a performance obligation is satisfied.
Revenue was historically comprised of sales of Hybrid systems for Class 8 semi-trucks, Class 8 semi-trucks outfitted with Hybrid systems and specific other features and services that met the definition of a performance obligation, including internet connectivity and data processing. We provided installation services for the Hybrid system onto the customers’ vehicle. The Company’s products were marketed and sold to end-user fleet customers in North America. When our contracts with customers contained multiple performance obligations and where material, the contract transaction price was allocated on a relative standalone selling price basis to each performance obligation.
We recognized revenue on Hybrid system sales and Class 8 semi-trucks outfitted with Hybrid systems upon delivery to, and acceptance of the vehicle by, the customer, which is when control transfers. Contracts were reviewed for significant financing components and payments were typically received within 30 days of delivery. The sale of a Hybrid system to an end-use fleet customer consisted of a completed modification to the customer vehicle and the installation services involved significant integration of the Hybrid system with the customer’s vehicle. Installation services were not distinct within the context of the contract and together with the sale of the Hybrid system represented a single performance obligation. We did not offer any sales returns. Amounts billed to customers related to shipping and handling were classified as revenue, and we have elected to recognize the cost for freight and shipping when control has transferred to the customer as a cost of revenue. Our policy is to exclude taxes collected from customers from the transaction price of contracts.
When a Class 8 semi-truck outfitted with a Hybrid system was resold to a customer, judgment was required to determine if we were the principal or agent in the arrangement. We considered factors such as, but not limited to, which entity had the primary responsibility for fulfilling the promise to provide the specified good or service, which entity had inventory risk before the specified good or service has been transferred to a customer and which entity had discretion in establishing the price for the specified good or service. We have determined that we were the principal in transactions involving the resale of Class 8 semi-trucks outfitted with the Hybrid system.
The disaggregation of our revenue sources is summarized as follows and is attributable to the U.S.:
Year Ended December 31,
20232022
Hybrid systems and other$416 $1,082 
Class 8 semi-truck prepared for Hybrid system upfit256 1,024 
Total product sales and other$672 $2,106 
The portion of our revenues from significant customers is summarized as follows:
Year Ended December 31,
20232022
Customer A65 %60 %
Customer B— 10 
Customer G25 — 
90 %70 %
Leases
We determine if an arrangement is a lease at inception of the contract. Operating leases are included in operating lease right-of-use (“ROU”) assets, current portion of operating lease liabilities, and operating lease liabilities, net of current portion in the accompanying consolidated balance sheets. We have lease agreements with lease and non-lease components, and have elected to utilize the practical expedient to account for lease and non-lease components together as a single combined lease component. Variable lease costs consist primarily of common area maintenance.
ROU assets represent the Company’s right to use underlying assets for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the leases. ROU assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. The discount rate used to calculate the present value for lease payments is the Company’s incremental borrowing rate, which is determined based on information available at lease commencement and is equal to the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term in an amount equal to the lease payments in a similar economic environment. The Company uses the implicit rate when readily determinable.
The Company’s real estate leases may include one or more options to renew, with the renewal extending the lease term for an additional one to five years. The exercise of lease renewal option is at the Company’s sole discretion. In general, the Company does not consider renewal options to be reasonably likely to be exercised, therefore renewal options are generally not recognized as part of the ROU assets and lease liabilities. Lease costs for lease payments are recognized on a straight-line basis over the lease term, unless there is a transfer of title or purchase option reasonably certain to be exercised. The Company does not record operating leases with an initial term of twelve months or less (“short-term leases”) in the consolidated balance sheets. Interest expense is recognized using the effective interest rate method, and the ROU asset is amortized over the useful life of the underlying asset.
Warranties
We have historically provided limited assurance-type warranties under our contracts and do not offer extended warranties or maintenance contracts. The warranty period typically extends for the lesser of two years or 200,000 miles following transfer of control and solely relates to correction of product defects during the warranty period. We recognize the cost of the warranty upon transfer of control based on estimated and historical claims rates and fulfillment costs, which are variable. Should product failure rates and fulfillment costs differ from these estimates, material revisions to the estimated warranty liability would be required. Warranty expense is recorded as a component of cost of revenue.
Marketing, Promotional and Advertising Costs
Marketing, promotional and advertising costs are expensed as incurred and are included as an element of selling, general and administrative expense in the consolidated statement of operations. Marketing, promotional and advertising costs were $1.3 million and $1.1 million for the years ended December 31, 2023 and 2022, respectively.
Research and Development Expense
Research and development costs did not meet the requirements to be recognized as an asset as the associated future benefits were at best uncertain and there was no alternative future use at the time the costs were incurred. Research and development costs include, but are not limited to, outsourced engineering services, allocated facilities costs, depreciation on equipment utilized in research and development activities, internal engineering and development expenses, materials, internally-developed software and employee related expenses (including salaries, benefits, travel, and share-based compensation) related to development of the Company’s products and services.
Share-Based Compensation
The Company accounts for share-based compensation in accordance with ASC 718, Compensation – Stock Compensation, under which shared based payments that involve the issuance of common stock to employees and nonemployees and meet the criteria for equity-classified awards are recognized in the financial statements as share-based compensation expense based on the fair value on the date of grant. The Company issues restricted stock awards to employees and nonemployees, utilizing new shares. The Company has elected to recognize the adjustment to share-based compensation expense in the period in which forfeitures occur. We recognize compensation expense for awards with only service conditions on a straight-line basis over the requisite service period for the entire award.
If factors change, and we utilize different assumptions including the probability of achieving performance conditions, share-based compensation cost on future award grants may differ significantly from share-based compensation cost recognized on past award grants. If there are any modifications or cancellations of the underlying unvested securities, we may be required to accelerate any remaining unearned share-based compensation cost or incur incremental cost. Share-based compensation cost affects our research and development and selling, general and administrative expenses.
Income Taxes
The Company accounts for income taxes in accordance with ASC 740, Income Taxes, under which deferred tax liabilities and assets are recognized for the expected future tax consequences of temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities and net operating loss and tax credit carryforwards. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized.
Due to the Company’s history of losses since inception, the net deferred tax assets have been fully offset by a valuation allowance at December 31, 2023 and 2022. 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. For the years ended December 31, 2023 and 2022, there were no uncertain tax positions taken or expected to be taken in the Company’s tax returns.
Net Loss Per Share
Basic loss per share (“EPS”) is computed by dividing net loss (the numerator) by the weighted average number of common shares outstanding for the period (the denominator). Diluted EPS attributable to common shareholders is computed by adjusting net loss by the weighted average number of common shares and potential common shares outstanding (if dilutive) during each
period. Potential common shares include shares issuable upon exercise of stock options and vesting of restricted stock awards (see Note 8). The number of potential common shares outstanding are calculated using the treasury stock or if-converted method.
Recent Accounting Pronouncements
In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740), to enhance transparency and decision usefulness of income tax disclosures. The pronouncement is effective for fiscal years beginning after December 15, 2024 and we expect a material impact to our disclosures as a result of adoption.
In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, to improve the disclosures about a public entity’s reportable segments. The pronouncement is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024 and we expect a material impact to our disclosures as a result of adoption.
In November 2021, the FASB issued ASU 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance, to increase transparency of government assistance which requires annual disclosures about transactions with a government entity that are accounted for by applying a grant or contribution accounting model by analogy. The pronouncement is effective for fiscal years beginning after December 15, 2021. The Company adopted ASU 2021-10 for the year ended December 31, 2022 with no material impact and updated its related disclosures.
v3.24.0.1
Investments
 12 Months Ended
Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]  
Investments
Note 4. Investments
The amortized cost, unrealized gains and losses, and fair value, and maturities of our held-to-maturity investments at December 31, 2023 and 2022 are summarized as follows:
Fair Value Measurements at December 31, 2023
Amortized CostGross Unrealized
Gains		Gross Unrealized
Losses		Fair Value
Commercial paper$35,218 $18 $(10)$35,226 
U.S. government agency bonds27,602 56 (186)27,472 
State and municipal bonds15,262 1 (48)15,215 
Corporate bonds and notes200,401 515 (255)200,661 
$278,483 $590 $(499)$278,574 
Fair Value Measurements at December 31, 2022
Amortized CostGross Unrealized
Gains		Gross Unrealized
Losses		Fair Value
Commercial paper$36,675 $2 $(161)$36,516 
U.S. government agency bonds12,441 6 (328)12,119 
State and municipal bonds40,104 28 (628)39,504 
Corporate bonds and notes213,088 76 (3,344)209,820 
$302,308 $112 $(4,461)$297,959 
December 31, 2023December 31, 2022
Amortized CostFair ValueAmortized CostFair Value
Due in one year or less$150,297 $149,934 $193,740 $191,094 
Due after one year through five years128,186 128,640 108,568 106,865 
$278,483 $278,574 $302,308 $297,959 
v3.24.0.1
Fair Value Measurements
 12 Months Ended
Dec. 31, 2023
Fair Value Disclosures [Abstract]  
Fair Value Measurements
Note 5. Fair Value Measurements
The fair value measurements of our financial assets at December 31, 2023 and 2022 are summarized as follows:
Fair Value Measurements at December 31, 2023
Level ILevel IILevel IIITotal
Cash and cash equivalents$12,881 $— $— $12,881 
Restricted cash8,583 — — 8,583 
Held-to-maturity investments:
Commercial paper— 35,226 — 35,226 
U.S. government agency bonds— 27,472 — 27,472 
State and municipal bonds— 15,215 — 15,215 
Corporate bonds and notes— 200,661 — 200,661 
$21,464 $278,574 $— $300,038 
Fair Value Measurements at December 31, 2022
Level ILevel IILevel IIITotal
Cash and cash equivalents$119,468 $— $— $119,468 
Restricted cash665 — — 665 
Held-to-maturity investments:
Commercial paper— 36,516 — 36,516 
U.S. government agency bonds— 12,119 — 12,119 
State and municipal bonds— 39,504 — 39,504 
Corporate bonds and notes— 209,820 — 209,820 
$120,133 $297,959 $— $418,092 
v3.24.0.1
Inventory
 12 Months Ended
Dec. 31, 2023
Inventory Disclosure [Abstract]  
Inventory
Note 6. Inventory
The carrying value of our inventory at December 31, 2023 and 2022 is summarized as follows:
December 31,
20232022
Raw materials$— $— 
Work in process— — 
Finished goods— 74 
$— $74 
We write-down inventory for any excess or obsolete inventories or when we believe that the net realizable value of inventories is less than the carrying value. During the years ended December 31, 2023 and 2022, we recorded write-downs of $1.1 million and $5.6 million, respectively, included primarily in cost of revenues.
v3.24.0.1
Capital Structure
 12 Months Ended
Dec. 31, 2023
Equity [Abstract]  
Capital Structure
Note 7. Capital Structure
Preferred Stock
The Company is authorized to issue 10,000,000 shares of preferred stock with a par value of $0.0001 per share. The Company’s Board is authorized to fix the voting rights, if any, designations, powers, preferences, the relative, participating, option or other special rights and any qualifications, limitations and restrictions thereof, applicable to the shares of each series. At December 31, 2023 and 2022, there were no shares of preferred stock issued and outstanding.
Common Stock
At December 31, 2023, the following shares of common stock were reserved for future issuance:
Stock options issued and outstanding522,971 
Authorized for future grant under 2020 Equity Incentive Plan6,988,626 
Authorized for future issuance under the Hyliion Holdings Corp. Employee Stock Purchase Plan1,800,000 
9,311,597 
Treasury Stock
In December 2023, we announced a share repurchase program which has no expiration date, authorizing the repurchase of up to $20.0 million in shares.
v3.24.0.1
Share-Based Compensation
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Share-Based Compensation
Note 8. Share-Based Compensation
2016 Equity Incentive Plan
The Hyliion Inc. 2016 Equity Incentive Plan (the “2016 Plan”), as amended in August 2017 and approved by the Board, permitted the granting of various awards including stock options (including both nonqualified options and incentive options), stock appreciation rights (“SARs”), stock awards, phantom stock units, performance awards and other share-based awards to employees, outside directors and consultants and advisors of the Company. Only stock options have been awarded to employees, consultants and advisors under the 2016 Plan. No further grants can be made under the 2016 Plan.
Employee and nonemployee stock options generally vest over four years, with a maximum term of ten years from the date of grant. These awards become available to the recipient upon the satisfaction of a vesting condition based on a period of service.
Activity in the 2016 Plan for the years ended December 31, 2023 and 2022 is summarized as follows:
Number of OptionsWeighted Average
Exercise Price (in Dollars)		Weighted Average
Remaining
Contractual Term
Outstanding at December 31, 20213,157,889 $0.16 6.6 years
Exercised(563,617)0.17 
Forfeited(52,833)0.20 
Outstanding at December 31, 20222,541,439 0.15 3.7 years
Exercised(1,936,018)0.13 
Forfeited(82,450)0.22 
Outstanding at December 31, 2023522,971 $0.20 4.3 years
Exercisable at December 31, 2023473,239 $0.20 4.1 years
At December 31, 2023, the options outstanding and exercisable had an intrinsic value of $0.3 million and $0.3 million, respectively. There were no options with an exercise price greater than the market price on December 31, 2023 to exclude from the intrinsic value computation. The intrinsic value of options exercised during the years ended December 31, 2023 and 2022 was $2.4 million and $2.4 million, respectively.
Share-based compensation expense under the 2016 Plan for the years ended December 31, 2023 and 2022 was nil and $0.1 million, respectively. There was no unrecognized compensation expense related the 2016 Plan at December 31, 2023.
2020 Equity Incentive Plan
On October 1, 2020, the Company’s shareholders approved a new long-term incentive award plan (the “2020 Plan”) in connection with the Business Combination. The 2020 Plan is administered by the Board and the compensation committee. The selection of participants, allotment of shares, determination of price and other conditions are approved by the Board and the compensation committee at its sole discretion in order to attract and retain personnel instrumental to the success of the Company. Under the 2020 Plan, the Company may grant an aggregate of 12,200,000 shares of common stock in the form of nonstatutory stock options, incentive stock options, SARs, restricted stock awards, performance awards and other awards. No stock options have been granted under the 2020 Plan.
Employee and director RSUs for which a grant date has been established generally vest over three to four years from the date of grant. These awards become available to the recipient upon the satisfaction of a vesting condition based on a period of service, and performance conditions (for certain awards to employees).
Activity in the 2020 Plan for the years ended December 31, 2023 and 2022 is summarized as follows:
Number of UnitsWeighted Average Grant Date Fair Value (in Dollars)
Unvested at December 31, 20211
1,556,794 $11.01 
Granted2
2,504,939 4.10 
Vested(470,426)11.07 
Forfeited3
(822,207)8.44 
Unvested at December 31, 20224
2,769,100 5.51 
Granted5
2,192,900 2.57 
Vested(1,350,172)5.28 
Forfeited6
(860,505)4.53 
Unvested at December 31, 20237
2,751,323 $3.59 
1 Excludes 1,910,914 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
2 Excludes 204,167 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
3 Excludes 130,000 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
4 Excludes 1,336,667 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
5 Excludes 25,000 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
6 Excludes 59,584 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
7 Excludes 633,750 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
Share-based compensation expense under the 2020 Plan for the years ended December 31, 2023 and 2022 was $6.2 million and $6.9 million, respectively. The fair value of RSUs that vested during the years ended December 31, 2023 and 2022 was $2.8 million and $1.7 million, respectively. There was $4.9 million of unrecognized compensation expense related to the 2020 Plan at December 31, 2023, which is expected to be recognized over the remaining vesting periods, subject to forfeitures, with a weighted-average period of 1.5 years.
As a result of execution of the Plan and failure to meet fiscal 2023 performance conditions for certain awards to employees, we expect 0.8 million RSU awards to be forfeited in the first quarter of fiscal 2024.
Employee Stock Purchase Plan
The Company has an authorized employee stock purchase plan (the “ESPP”) that would enable employees to contribute up to 15% of their base compensation toward the purchase of the Company’s common stock at 85% of its market value on the first or last day of each offering period. The ESPP has not been implemented through December 31, 2023.
v3.24.0.1
Leases
 12 Months Ended
Dec. 31, 2023
Leases [Abstract]  
Leases
Note 9. Leases
The Company enters into operating leases for its corporate office, temporary offices, vehicles and equipment. In addition, the Company may enter into arrangements whereby portions of the leased premises are subleased to third parties and are classified as operating leases.
In May 2023, the Company executed a lease for its facility in Milford, Ohio, with a term through 2028 including the option to extend the term for up to two consecutive terms of three years, which was not reasonably certain to be exercised at the commencement date.
In December 2021, the Company amended the lease for its corporate office. This amendment increased the amount of space under the original lease, adjusted the monthly lease payments, and decreased the term of the lease through 2027. The Company accounted for this extension as a lease modification and recorded a decrease to the operating lease ROU asset and lease liability. The lease amendment includes the option to extend the term for up to two consecutive terms of five years, which was not reasonably certain to be exercised at the modification date.
The following table provides a summary of the components of lease income, costs and rent, which are included within research and development and selling, general and administrative expense:
Year Ended December 31,
20232022
Operating lease costs:
Operating lease cost$2,239 $1,921 
Short-term lease cost508 199 
Variable lease cost682 622 
Total operating lease costs$3,429 $2,742 
The following table provides the weighted-average lease terms and discount rates used for the Company’s operating leases:
December 31,
20232022
Weighted-average remaining lease term:
Operating leases3.6 years4.3 years
Weighted-average discount rate:
Operating leases8.7 %7.1 %
The following table provides a summary of operating lease liability maturities for the next five years and thereafter at December 31, 2023:
2024$1,497 
20252,900 
20262,989 
20271,426 
2028306 
Thereafter— 
Total minimum lease payments9,118 
Less: imputed interest(1,479)
Total lease obligations$7,639 
Leases
Note 9. Leases
The Company enters into operating leases for its corporate office, temporary offices, vehicles and equipment. In addition, the Company may enter into arrangements whereby portions of the leased premises are subleased to third parties and are classified as operating leases.
In May 2023, the Company executed a lease for its facility in Milford, Ohio, with a term through 2028 including the option to extend the term for up to two consecutive terms of three years, which was not reasonably certain to be exercised at the commencement date.
In December 2021, the Company amended the lease for its corporate office. This amendment increased the amount of space under the original lease, adjusted the monthly lease payments, and decreased the term of the lease through 2027. The Company accounted for this extension as a lease modification and recorded a decrease to the operating lease ROU asset and lease liability. The lease amendment includes the option to extend the term for up to two consecutive terms of five years, which was not reasonably certain to be exercised at the modification date.
The following table provides a summary of the components of lease income, costs and rent, which are included within research and development and selling, general and administrative expense:
Year Ended December 31,
20232022
Operating lease costs:
Operating lease cost$2,239 $1,921 
Short-term lease cost508 199 
Variable lease cost682 622 
Total operating lease costs$3,429 $2,742 
The following table provides the weighted-average lease terms and discount rates used for the Company’s operating leases:
December 31,
20232022
Weighted-average remaining lease term:
Operating leases3.6 years4.3 years
Weighted-average discount rate:
Operating leases8.7 %7.1 %
The following table provides a summary of operating lease liability maturities for the next five years and thereafter at December 31, 2023:
2024$1,497 
20252,900 
20262,989 
20271,426 
2028306 
Thereafter— 
Total minimum lease payments9,118 
Less: imputed interest(1,479)
Total lease obligations$7,639 
v3.24.0.1
Property and Equipment, Net
 12 Months Ended
Dec. 31, 2023
Property, Plant and Equipment [Abstract]  
Property and Equipment, Net
Note 10. Property and Equipment, Net
Property and equipment, net at December 31, 2023 and 2022 is summarized as follows:
December 31,
20232022
Production machinery and equipment$10,376 $5,897 
Vehicles2,013 817 
Leasehold improvements2,236 1,002 
Office furniture and fixtures223 162 
Computers and related equipment1,963 1,367 
16,811 9,245 
Less: accumulated depreciation(6,824)(3,639)
Total property and equipment, net$9,987 $5,606 
Depreciation expense for the years ended December 31, 2023 and 2022 totaled approximately $3.2 million and $1.1 million, respectively. For the year ended December 31, 2023, $0.6 million, $1.7 million, and $0.9 million was included in selling, general and administrative expenses, research and development expenses and exit and termination costs, respectively, in the consolidated statements of operations. For the year ended December 31, 2022, $0.3 million and $0.8 million was included in selling, general and administrative expenses, and research and development expenses, respectively, in the consolidated statements of operations.
v3.24.0.1
Accrued Expenses and Other Current Liabilities
 12 Months Ended
Dec. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]  
Accrued Expenses and Other Current Liabilities
Note 11. Accrued Expenses and Other Current Liabilities
Accrued expenses and other current liabilities at December 31, 2023 and 2022 are summarized as follows:
December 31,
20232022
Accrued professional services and other$2,606 $5,834 
Accrued compensation and related benefits1,510 4,773 
Other accrued liabilities1,922 928 
Accrued severance, contract termination, and other charges4,013 — 
$10,051 $11,535 
v3.24.0.1
Warranties
 12 Months Ended
Dec. 31, 2023
Guarantees and Product Warranties [Abstract]  
Warranties
Note 12. Warranties
The change in warranty liability for the years ended December 31, 2023 and 2022 is summarized as follows and included within accrued expenses and other current liabilities and other liabilities in the consolidated balance sheets:
Year ended December 31,
20232022
Balance at beginning of period$527 $44 
Accrual for warranties issued218 644 
Net changes in accrual related to pre-existing warranties(154)(7)
Warranty charges(182)(154)
Balance at end of period$409 $527 
v3.24.0.1
Income Taxes
 12 Months Ended
Dec. 31, 2023
Income Tax Disclosure [Abstract]  
Income Taxes
Note 13. Income Taxes
The income tax provision for the years ended December 31, 2023 and 2022 is summarized as follows:
Year Ended December 31,
20232022
Current tax expense:
Federal$— $— 
State— — 
Total current tax expense$— $— 
Deferred tax (benefit) expense:
Federal$(25,328)$(34,296)
State— (40)
Valuation allowance25,328 34,336 
Total deferred tax expense$— $— 
The components of deferred taxes at December 31, 2023 and 2022 are summarized as follows:
December 31,
20232022
Deferred tax assets:
Federal net operating loss carryforwards$62,561 $48,186 
State net operating loss carryforwards491 491 
Operating lease obligation1,604 1,537 
Section 174 expenditures26,444 14,840 
R&D tax credit4,714 4,714 
Other3,235 3,148 
Intangible assets, net5,522 6,001 
Total deferred tax assets104,571 78,917 
Less: valuation allowance(102,803)(77,475)
Deferred tax assets, net of valuation allowance1,768 1,442 
Deferred tax liabilities:
Operating lease right of use asset, net1,485 1,359 
Property and equipment, net283 83 
Total deferred tax liabilities1,768 1,442 
Net deferred tax assets$— $— 
The reconciliation of taxes at the federal statutory rate to the Company’s provision for income taxes for the years ended December 31, 2023 and 2022 is summarized as follows:
Year Ended December 31,
20232022
Provision at statutory rate of 21%$(25,937)$(32,205)
State tax expense— 492 
Stock options520 533 
Other89 865 
R&D tax credit— (4,021)
Change in valuation allowance25,328 34,336 
$— $— 
In assessing the realizability of deferred tax assets, management considered whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considered the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. Based upon the level of historical taxable income and projections for future taxable income over the periods in which the deferred tax assets are deductible, management believes it is more likely than not that the Company will not realize the benefits of these deductible differences at December 31, 2023.
The Company had federal net operating loss carryforwards of $297.9 million and $229.5 million at December 31, 2023 and 2022, respectively. At December 31, 2023, $10.5 million of this amount will begin to expire in 2036 and the remaining $287.4 million has an indefinite carryforward period. The Company had state net operating loss carryforwards of $12.5 million and $12.5 million at December 31, 2023 and 2022, respectively, that will begin to expire beginning in 2036 and research and development credits of $4.7 million that will begin to expire in 2037. The Company's ability to utilize a portion of net operating loss carryforwards and credits to offset future taxable income, and tax, respectively, is subject to certain limitations under Section 382 of the Internal Revenue Code upon changes in equity ownership of the Company. Due to such limitation, $2.0 million of the Company’s net operating loss and less than $0.1 million of the Company’s R&D credits will expire unused, regardless of taxable income in future years.
The Company files a United States federal income tax return, as well as income tax returns in various states. The tax returns for years 2020 and thereafter remain open for examination. However, the taxing authorities have the ability to review the propriety of tax losses created in closed tax years to the extent such losses are utilized in an open tax year.
v3.24.0.1
Commitments and Contingencies
 12 Months Ended
Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies
Note 14. Commitments and Contingencies
Economic Incentive Agreement
During the year ended December 31, 2018, the Company entered into an agreement with the Cedar Park Economic Development Corporation (“EDC”), whereby the Company would receive cash grants from the EDC contingent upon the Company fulfilling and maintaining certain corporate office lease and employment requirements. The specified requirements must be met on or before specific measurement dates and maintained throughout the term of the agreement, which expires effective December 31, 2025.
As the terms of the EDC grant agreement require the Company to meet and maintain all of the performance requirements throughout the term of the agreement and the Company did not meet the conditions for the grant funding received through December 31, 2023, all amounts received from the EDC are subject to refund. Accordingly, total grant funding of $1.1 million is included within other current accrued liabilities as of December 31, 2023. Total grant funding of $0.9 million was included within other noncurrent liabilities as of December 31, 2022. Under the agreement, the EDC has the right to file a security interest to all assets of the Company.
Legal Proceedings
The Company is periodically involved in legal proceedings, legal actions and claims arising in the normal course of business, including proceedings relating to product liability, intellectual property, safety and health, employment and other matters. The Company believes that the outcome of such legal proceedings, legal actions and claims will not have a significant adverse effect on the Company’s financial position, results of operations or cash flows.
v3.24.0.1
Net Loss Per Share
 12 Months Ended
Dec. 31, 2023
Earnings Per Share [Abstract]  
Net Loss Per Share
Note 15. Net Loss Per Share
The computation of basic and diluted net loss per share for the years ended December 31, 2023 and 2022 is summarized as follows (in thousands, except share and per share data):
Year Ended December 31,
20232022
Numerator:
Net loss attributable to common stockholders$(123,510)$(153,357)
Denominator:
Weighted average shares outstanding, basic and diluted181,411,069 175,400,486 
Net loss per share, basic and diluted$(0.68)$(0.87)
Potential common shares excluded from the computation of diluted net loss per share because including them would have had an anti-dilutive effect for the years ended December 31, 2023 and 2022 are summarized as follows:
Year Ended December 31,
20232022
Unexercised stock options522,971 2,541,439 
Unvested restricted stock units*3,385,073 4,105,673 
3,908,044 6,647,112 
* Potential common shares from unvested restricted stock units for the years ended December 31, 2023 and 2022 include 633,750 and 1,336,667 shares, respectively, where no accounting grant date has been established.
v3.24.0.1
Supplemental Cash Flow Information
 12 Months Ended
Dec. 31, 2023
Supplemental Cash Flow Elements [Abstract]  
Supplemental Cash Flow Information
Note 16. Supplemental Cash Flow Information
Supplemental cash flow information for the years ended December 31, 2023 and 2022 is summarized as follows:
Year Ended December 31,
20232022
Cash paid for interest$— $— 
Cash paid for taxes$— $— 
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases$(2,470)$(1,921)
Right-of-use assets obtained in exchange for lease obligations$2,096 $— 
Year Ended December 31,
20232022
Supplemental disclosure of noncash investing and financing activities:
Common stock issued for purchase of assets$— $16,115 
Acquisitions of property and equipment and intangible assets included in accounts payable and other$292 $59 
v3.24.0.1
Retirement Plan
 12 Months Ended
Dec. 31, 2023
Retirement Benefits [Abstract]  
Retirement Plan
Note 17. 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 or post-tax basis. The 401(k) plan eligibility conditions require participants are at least 21 years old to participate. Eligibility entry date is the first of the month following date of hire, or the first of the month following the date the employee turns 21 years old. Plan participants may make elective contributions up to the maximum percentage of compensation and dollar amount allowed under the Internal Revenue Code and are always 100% vested in their elective contributions. The Company has also established a Profit Sharing plan in which the employer may make contributions on the employee’s behalf (“discretionary employer contributions”). The Company did not make any Profit Sharing contributions during the years ended December 31, 2023 and 2022.
v3.24.0.1
Summary of Significant Accounting Policies (Policies)
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Basis of Presentation and Principles of Consolidation
Basis of Presentation and Principles of Consolidation
The accompanying consolidated financial statements include the accounts of Hyliion Holdings Corp. and its wholly owned subsidiary. Intercompany transactions and balances have been eliminated upon consolidation. The consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the rules and regulations of the Unites States Securities and Exchange Commission (“SEC”). Any reference in these footnotes to the applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Certain prior period balances have been reclassified to conform to the current period presentation in the consolidated financial statements and the accompanying notes.
These consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities in the normal course of business. The Company is an early-stage growth company and has generated negative cash flows from operating activities since inception.
Use of Estimates
Use of Estimates
The preparation of financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the balance sheet date, as well as reported amounts of expenses during the reporting period. The Company’s most significant estimates and judgments involve inventory, acquisitions, disposals, income taxes, valuation of share-based compensation, and probability-weighted future cash flows associated with long-lived asset impairment reviews. Management bases its estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making
judgments about the carrying values of assets and liabilities. Actual results could differ from those estimates, and such differences could be material to the Company’s consolidated financial statements.
Segment Information
Segment Information
ASC 280, Segment Reporting, defines operating segments as components of an enterprise where discrete financial information is available that is evaluated regularly by the chief operating decision-maker (“CODM”) in deciding how to allocate resources and in assessing performance. The Company operates as a single operating segment. The Company’s CODM is the chief executive officer, who has ultimate responsibility for the operating performance of the Company and the allocation of resources. The CODM uses cash flows as the primary measure to manage the business and does not segment the business for internal reporting or decision making.
Concentration of Supplier Risk
Concentration of Supplier Risk
The Company is dependent on certain suppliers, the majority of which are single source suppliers, and the inability of these suppliers to deliver necessary components of the Company’s products in a timely manner at prices, quality levels and volumes that are acceptable, or the Company’s inability to efficiently manage these components from these suppliers, could have a material adverse effect on the Company’s business, prospects, financial condition and operating results.
Cash and Cash Equivalents
Cash and Cash Equivalents
The Company considers all highly liquid investments with a maturity date of 90 days or less at the time of purchase to be cash and cash equivalents only if in checking, savings or money market accounts. Cash and cash equivalents include cash held in banks and money market accounts and are carried at cost, which approximates fair value. The Company maintains cash in excess of federally insured limits at financial institutions which it believes are of high credit quality and has not incurred any losses related to these balances to date. The Company believes its credit risk, with respect to these financial institutions to be minimal.
Accounts Receivable
Accounts Receivable
Accounts receivable are stated at a gross invoice amount, net of an allowance for doubtful accounts. The allowance for doubtful accounts is maintained at a level considered adequate to provide for potential account losses on the balance based on the Company’s evaluation of the anticipated impact of current economic conditions, changes in the character and size of the balance, past and expected future loss experience and other pertinent factors.
Investments
Investments
The Company’s investments consist of corporate bonds, U.S. treasury and agency securities, state and local municipal bonds and commercial paper, all of which are classified as held-to-maturity, with a maturity date of 36-months or less at the time of purchase. The Company determines the appropriate classification of investments at the time of purchase and re-evaluates such designation as of each balance sheet date. Investments are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization, along with interest, is included in interest income. The Company uses the specific identification method to determine the cost basis of securities sold.
Investments are impaired when a decline in fair value is judged to be other-than-temporary. The Company evaluates investments for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to other income (expense) and a new cost basis in the investment is established.
Fair Value Measurements
Fair Value Measurements
ASC 820, Fair Value Measurements, clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based upon assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820 establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:
Level I: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the Company can access at the measurement date;
Level II: Significant other observable inputs other than level I prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data; and
Level III: Significant unobservable inputs that reflect the Company’s own assumptions about the assumptions that market participants would use in pricing an asset or liability.
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.
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 and restricted cash, accounts receivable, investments, accounts payable and accrued expenses. The carrying value of cash and cash equivalents and restricted cash, accounts receivable, accounts payable and accrued expenses approximate fair value because of the short-term nature of those instruments. The fair value of investments is based on quoted prices for identical or similar instruments in markets that are not active. As a result, investments are classified within Level II of the fair value hierarchy.
Inventories
Inventories
Inventory is comprised of raw materials, work in process and finished goods and includes the cost of raw materials, freight, direct and indirect labor and allocations of other conversion costs and overhead. Semi-truck inventory is valued using the specific identification cost method and all other inventory is valued using the moving-average cost method. Inventory is stated at the lower of cost or net realizable value. We review our inventory to determine whether its carrying value exceeds the net amount realizable we expect to receive upon the ultimate sale of the inventory. This requires us to determine the estimated
selling price of inventory less the estimated cost to convert the inventory on-hand into a finished product and other costs, which we determined includes the cost of installation and validation, to align with the transfer of control to customers in our revenue policy. Inventory write-downs are first allocated to all other inventory with any residual allocated to semi-truck inventory.
Once inventory is written-down based on a lower of cost or net realizable value analysis, that amount establishes the new carrying value of inventory if written-down at year end, and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established cost basis. Interim impairments are reversed and reassessed at each reporting period.
During the fourth quarter of 2021, we changed from a research and development phase to a production phase for our Hybrid system product. Through December 31, 2023, we have not yet commercialized the KARNO generator. Costs incurred for components acquired prior to our determination of reaching a commercial stage are expensed as research and development costs, resulting in zero cost basis for those components. As a result, moving-average prices for inventory that is capitalized in future periods may be significantly affected by those zero cost items.
Prepaid Expenses and Other Current Assets
Prepaid Expenses and Other Current Assets
Prepaid expenses and other current assets include prepaid insurance, rent and supplies, which are expected to be recognized, received or realized within the next 12 months.
Property and Equipment, Net
Property and Equipment, Net
Property and equipment, net is stated at cost less accumulated depreciation, or if acquired in a business combination, at allocated fair value at the date of acquisition. Depreciation is calculated using the straight-line method, based upon the following estimated useful lives:
Production machinery and equipment
2 to 7 years
Vehicles
3 to 7 years
Leasehold improvements
shorter of lease term or 7 years
Demo fleet systems
2 to 3 years
Furniture and fixtures3 years
Computers and related equipment
3 to 7 years
Major renewals and 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 consolidated statement of operations as a component of other income (expense). All long-lived assets are located in the United States.
Impairment of Long-Lived Assets
Impairment of Long-Lived Assets
The Company reviews long-lived assets, including property and equipment and intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate that an asset group’s carrying amount may not be recoverable. The Company conducts its long-lived asset impairment analysis in accordance with ASC 360-10, Impairment or Disposal of Long-Lived Assets, which requires the Company to group assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and evaluate the asset group against the sum of the undiscounted future cash flows. If the undiscounted cash flows do not indicate the carrying amount of the asset group is recoverable, an impairment charge is measured as the amount by which the carrying amount of the asset group exceeds its fair value.
Revenue
Revenue
The Company follows five steps to recognize revenue from contracts with customers under ASC 606, Revenue from Contracts with Customers, which are:
•Step 1: Identify the contract(s) with a customer;
•Step 2: Identify the performance obligations in the contract;
•Step 3: Determine the transaction price;
•Step 4: Allocate the transaction price to the performance obligations in the contract; and
•Step 5: Recognize revenue when (or as) a performance obligation is satisfied.
Revenue was historically comprised of sales of Hybrid systems for Class 8 semi-trucks, Class 8 semi-trucks outfitted with Hybrid systems and specific other features and services that met the definition of a performance obligation, including internet connectivity and data processing. We provided installation services for the Hybrid system onto the customers’ vehicle. The Company’s products were marketed and sold to end-user fleet customers in North America. When our contracts with customers contained multiple performance obligations and where material, the contract transaction price was allocated on a relative standalone selling price basis to each performance obligation.
We recognized revenue on Hybrid system sales and Class 8 semi-trucks outfitted with Hybrid systems upon delivery to, and acceptance of the vehicle by, the customer, which is when control transfers. Contracts were reviewed for significant financing components and payments were typically received within 30 days of delivery. The sale of a Hybrid system to an end-use fleet customer consisted of a completed modification to the customer vehicle and the installation services involved significant integration of the Hybrid system with the customer’s vehicle. Installation services were not distinct within the context of the contract and together with the sale of the Hybrid system represented a single performance obligation. We did not offer any sales returns. Amounts billed to customers related to shipping and handling were classified as revenue, and we have elected to recognize the cost for freight and shipping when control has transferred to the customer as a cost of revenue. Our policy is to exclude taxes collected from customers from the transaction price of contracts.
When a Class 8 semi-truck outfitted with a Hybrid system was resold to a customer, judgment was required to determine if we were the principal or agent in the arrangement. We considered factors such as, but not limited to, which entity had the primary responsibility for fulfilling the promise to provide the specified good or service, which entity had inventory risk before the specified good or service has been transferred to a customer and which entity had discretion in establishing the price for the specified good or service. We have determined that we were the principal in transactions involving the resale of Class 8 semi-trucks outfitted with the Hybrid system.
Leases
Leases
We determine if an arrangement is a lease at inception of the contract. Operating leases are included in operating lease right-of-use (“ROU”) assets, current portion of operating lease liabilities, and operating lease liabilities, net of current portion in the accompanying consolidated balance sheets. We have lease agreements with lease and non-lease components, and have elected to utilize the practical expedient to account for lease and non-lease components together as a single combined lease component. Variable lease costs consist primarily of common area maintenance.
ROU assets represent the Company’s right to use underlying assets for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the leases. ROU assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. The discount rate used to calculate the present value for lease payments is the Company’s incremental borrowing rate, which is determined based on information available at lease commencement and is equal to the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term in an amount equal to the lease payments in a similar economic environment. The Company uses the implicit rate when readily determinable.
The Company’s real estate leases may include one or more options to renew, with the renewal extending the lease term for an additional one to five years. The exercise of lease renewal option is at the Company’s sole discretion. In general, the Company does not consider renewal options to be reasonably likely to be exercised, therefore renewal options are generally not recognized as part of the ROU assets and lease liabilities. Lease costs for lease payments are recognized on a straight-line basis over the lease term, unless there is a transfer of title or purchase option reasonably certain to be exercised. The Company does not record operating leases with an initial term of twelve months or less (“short-term leases”) in the consolidated balance sheets. Interest expense is recognized using the effective interest rate method, and the ROU asset is amortized over the useful life of the underlying asset.
Warranties
Warranties
We have historically provided limited assurance-type warranties under our contracts and do not offer extended warranties or maintenance contracts. The warranty period typically extends for the lesser of two years or 200,000 miles following transfer of control and solely relates to correction of product defects during the warranty period. We recognize the cost of the warranty upon transfer of control based on estimated and historical claims rates and fulfillment costs, which are variable. Should product failure rates and fulfillment costs differ from these estimates, material revisions to the estimated warranty liability would be required. Warranty expense is recorded as a component of cost of revenue.
Marketing, Promotional and Advertising Costs
Marketing, Promotional and Advertising Costs
Marketing, promotional and advertising costs are expensed as incurred and are included as an element of selling, general and administrative expense in the consolidated statement of operations.
Research and Development Expense
Research and Development Expense
Research and development costs did not meet the requirements to be recognized as an asset as the associated future benefits were at best uncertain and there was no alternative future use at the time the costs were incurred. Research and development costs include, but are not limited to, outsourced engineering services, allocated facilities costs, depreciation on equipment utilized in research and development activities, internal engineering and development expenses, materials, internally-developed software and employee related expenses (including salaries, benefits, travel, and share-based compensation) related to development of the Company’s products and services.
Share-Based Compensation
Share-Based Compensation
The Company accounts for share-based compensation in accordance with ASC 718, Compensation – Stock Compensation, under which shared based payments that involve the issuance of common stock to employees and nonemployees and meet the criteria for equity-classified awards are recognized in the financial statements as share-based compensation expense based on the fair value on the date of grant. The Company issues restricted stock awards to employees and nonemployees, utilizing new shares. The Company has elected to recognize the adjustment to share-based compensation expense in the period in which forfeitures occur. We recognize compensation expense for awards with only service conditions on a straight-line basis over the requisite service period for the entire award.
If factors change, and we utilize different assumptions including the probability of achieving performance conditions, share-based compensation cost on future award grants may differ significantly from share-based compensation cost recognized on past award grants. If there are any modifications or cancellations of the underlying unvested securities, we may be required to accelerate any remaining unearned share-based compensation cost or incur incremental cost. Share-based compensation cost affects our research and development and selling, general and administrative expenses.
Income Taxes
Income Taxes
The Company accounts for income taxes in accordance with ASC 740, Income Taxes, under which deferred tax liabilities and assets are recognized for the expected future tax consequences of temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities and net operating loss and tax credit carryforwards. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized.
Due to the Company’s history of losses since inception, the net deferred tax assets have been fully offset by a valuation allowance at December 31, 2023 and 2022. 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. For the years ended December 31, 2023 and 2022, there were no uncertain tax positions taken or expected to be taken in the Company’s tax returns.
Net Loss Per Share
Net Loss Per Share
Basic loss per share (“EPS”) is computed by dividing net loss (the numerator) by the weighted average number of common shares outstanding for the period (the denominator). Diluted EPS attributable to common shareholders is computed by adjusting net loss by the weighted average number of common shares and potential common shares outstanding (if dilutive) during each
period. Potential common shares include shares issuable upon exercise of stock options and vesting of restricted stock awards (see Note 8). The number of potential common shares outstanding are calculated using the treasury stock or if-converted method.
Recent Accounting Pronouncements
Recent Accounting Pronouncements
In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740), to enhance transparency and decision usefulness of income tax disclosures. The pronouncement is effective for fiscal years beginning after December 15, 2024 and we expect a material impact to our disclosures as a result of adoption.
In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, to improve the disclosures about a public entity’s reportable segments. The pronouncement is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024 and we expect a material impact to our disclosures as a result of adoption.
In November 2021, the FASB issued ASU 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance, to increase transparency of government assistance which requires annual disclosures about transactions with a government entity that are accounted for by applying a grant or contribution accounting model by analogy. The pronouncement is effective for fiscal years beginning after December 15, 2021. The Company adopted ASU 2021-10 for the year ended December 31, 2022 with no material impact and updated its related disclosures.
v3.24.0.1
Acquisitions and Disposals (Tables)
 12 Months Ended
Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]  
Schedule of Changes in Plan Liabilities
The change in total liabilities associated with the Plan, excluding warranty balances in Note 12, is summarized as follows (in millions). These balances are included within accrued expenses and other current liabilities, as presented in Note 11, with the remainder included within accounts payable.
December 31, 2022Charged to ExpenseCosts Paid or SettledDecember 31, 2023
Employee severance and retention$— $1.2 $(0.1)$1.1 
Contract terminations— 8.2 (1.7)6.5 
$— $9.4 $(1.8)$7.6 
v3.24.0.1
Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Schedule of Restrictions on Cash and Cash Equivalents
Total cash and cash equivalents and restricted cash as presented in the consolidated statements of cash flows is summarized as follows:
December 31, 2023December 31, 2022December 31, 2021
Cash and cash equivalents$12,881 $119,468 $258,445 
Restricted cash included in prepaid expenses and other current assets7,918 — — 
Restricted cash included in other assets665 665 665 
$21,464 $120,133 $259,110 
Schedule of Significant Customers
The portion of our net accounts receivable from significant customers is summarized as follows:
December 31,
20232022
Customer A— %82 %
Customer C— 12 
— %94 %
The portion of our revenues from significant customers is summarized as follows:
Year Ended December 31,
20232022
Customer A65 %60 %
Customer B— 10 
Customer G25 — 
90 %70 %
Schedule of Estimated Useful Lives Depreciation is calculated using the straight-line method, based upon the following estimated useful lives:
Production machinery and equipment
2 to 7 years
Vehicles
3 to 7 years
Leasehold improvements
shorter of lease term or 7 years
Demo fleet systems
2 to 3 years
Furniture and fixtures3 years
Computers and related equipment
3 to 7 years
Schedule of Disaggregation of Revenue
The disaggregation of our revenue sources is summarized as follows and is attributable to the U.S.:
Year Ended December 31,
20232022
Hybrid systems and other$416 $1,082 
Class 8 semi-truck prepared for Hybrid system upfit256 1,024 
Total product sales and other$672 $2,106 
v3.24.0.1
Investments (Tables)
 12 Months Ended
Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]  
Schedule of Amortized Cost, Unrealized Gains and Losses, and Fair Value
The amortized cost, unrealized gains and losses, and fair value, and maturities of our held-to-maturity investments at December 31, 2023 and 2022 are summarized as follows:
Fair Value Measurements at December 31, 2023
Amortized CostGross Unrealized
Gains		Gross Unrealized
Losses		Fair Value
Commercial paper$35,218 $18 $(10)$35,226 
U.S. government agency bonds27,602 56 (186)27,472 
State and municipal bonds15,262 1 (48)15,215 
Corporate bonds and notes200,401 515 (255)200,661 
$278,483 $590 $(499)$278,574 
Fair Value Measurements at December 31, 2022
Amortized CostGross Unrealized
Gains		Gross Unrealized
Losses		Fair Value
Commercial paper$36,675 $2 $(161)$36,516 
U.S. government agency bonds12,441 6 (328)12,119 
State and municipal bonds40,104 28 (628)39,504 
Corporate bonds and notes213,088 76 (3,344)209,820 
$302,308 $112 $(4,461)$297,959 
Schedule of Investment Maturity
December 31, 2023December 31, 2022
Amortized CostFair ValueAmortized CostFair Value
Due in one year or less$150,297 $149,934 $193,740 $191,094 
Due after one year through five years128,186 128,640 108,568 106,865 
$278,483 $278,574 $302,308 $297,959 
v3.24.0.1
Fair Value Measurements (Tables)
 12 Months Ended
Dec. 31, 2023
Fair Value Disclosures [Abstract]  
Schedule of Assets and Liabilities That Are Measured at Fair Value on a Recurring Basis
The fair value measurements of our financial assets at December 31, 2023 and 2022 are summarized as follows:
Fair Value Measurements at December 31, 2023
Level ILevel IILevel IIITotal
Cash and cash equivalents$12,881 $— $— $12,881 
Restricted cash8,583 — — 8,583 
Held-to-maturity investments:
Commercial paper— 35,226 — 35,226 
U.S. government agency bonds— 27,472 — 27,472 
State and municipal bonds— 15,215 — 15,215 
Corporate bonds and notes— 200,661 — 200,661 
$21,464 $278,574 $— $300,038 
Fair Value Measurements at December 31, 2022
Level ILevel IILevel IIITotal
Cash and cash equivalents$119,468 $— $— $119,468 
Restricted cash665 — — 665 
Held-to-maturity investments:
Commercial paper— 36,516 — 36,516 
U.S. government agency bonds— 12,119 — 12,119 
State and municipal bonds— 39,504 — 39,504 
Corporate bonds and notes— 209,820 — 209,820 
$120,133 $297,959 $— $418,092 
v3.24.0.1
Inventory (Tables)
 12 Months Ended
Dec. 31, 2023
Inventory Disclosure [Abstract]  
Schedule of Inventory
The carrying value of our inventory at December 31, 2023 and 2022 is summarized as follows:
December 31,
20232022
Raw materials$— $— 
Work in process— — 
Finished goods— 74 
$— $74 
v3.24.0.1
Capital Structure (Tables)
 12 Months Ended
Dec. 31, 2023
Equity [Abstract]  
Schedule of Common Stock Reserved
At December 31, 2023, the following shares of common stock were reserved for future issuance:
Stock options issued and outstanding522,971 
Authorized for future grant under 2020 Equity Incentive Plan6,988,626 
Authorized for future issuance under the Hyliion Holdings Corp. Employee Stock Purchase Plan1,800,000 
9,311,597 
v3.24.0.1
Share-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Schedule of Share Option Activity
Activity in the 2016 Plan for the years ended December 31, 2023 and 2022 is summarized as follows:
Number of OptionsWeighted Average
Exercise Price (in Dollars)		Weighted Average
Remaining
Contractual Term
Outstanding at December 31, 20213,157,889 $0.16 6.6 years
Exercised(563,617)0.17 
Forfeited(52,833)0.20 
Outstanding at December 31, 20222,541,439 0.15 3.7 years
Exercised(1,936,018)0.13 
Forfeited(82,450)0.22 
Outstanding at December 31, 2023522,971 $0.20 4.3 years
Exercisable at December 31, 2023473,239 $0.20 4.1 years
Activity in the 2020 Plan for the years ended December 31, 2023 and 2022 is summarized as follows:
Number of UnitsWeighted Average Grant Date Fair Value (in Dollars)
Unvested at December 31, 20211
1,556,794 $11.01 
Granted2
2,504,939 4.10 
Vested(470,426)11.07 
Forfeited3
(822,207)8.44 
Unvested at December 31, 20224
2,769,100 5.51 
Granted5
2,192,900 2.57 
Vested(1,350,172)5.28 
Forfeited6
(860,505)4.53 
Unvested at December 31, 20237
2,751,323 $3.59 
1 Excludes 1,910,914 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
2 Excludes 204,167 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
3 Excludes 130,000 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
4 Excludes 1,336,667 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
5 Excludes 25,000 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
6 Excludes 59,584 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
7 Excludes 633,750 shares underlying RSU awards with performance conditions, which have not been accounted for because no accounting grant date has been established.
v3.24.0.1
Leases (Tables)
 12 Months Ended
Dec. 31, 2023
Leases [Abstract]  
Schedule of Operating Lease Costs and Finance Lease Costs
The following table provides a summary of the components of lease income, costs and rent, which are included within research and development and selling, general and administrative expense:
Year Ended December 31,
20232022
Operating lease costs:
Operating lease cost$2,239 $1,921 
Short-term lease cost508 199 
Variable lease cost682 622 
Total operating lease costs$3,429 $2,742 
Schedule of Weighted-average Lease Terms and Discount Rates
The following table provides the weighted-average lease terms and discount rates used for the Company’s operating leases:
December 31,
20232022
Weighted-average remaining lease term:
Operating leases3.6 years4.3 years
Weighted-average discount rate:
Operating leases8.7 %7.1 %
Schedule of Lease Liability Maturities for the Next Five Years
The following table provides a summary of operating lease liability maturities for the next five years and thereafter at December 31, 2023:
2024$1,497 
20252,900 
20262,989 
20271,426 
2028306 
Thereafter— 
Total minimum lease payments9,118 
Less: imputed interest(1,479)
Total lease obligations$7,639 
v3.24.0.1
Property and Equipment, Net (Tables)
 12 Months Ended
Dec. 31, 2023
Property, Plant and Equipment [Abstract]  
Schedule of Property and Equipment, Net
Property and equipment, net at December 31, 2023 and 2022 is summarized as follows:
December 31,
20232022
Production machinery and equipment$10,376 $5,897 
Vehicles2,013 817 
Leasehold improvements2,236 1,002 
Office furniture and fixtures223 162 
Computers and related equipment1,963 1,367 
16,811 9,245 
Less: accumulated depreciation(6,824)(3,639)
Total property and equipment, net$9,987 $5,606 
v3.24.0.1
Accrued Expenses and Other Current Liabilities (Tables)
 12 Months Ended
Dec. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]  
Schedule of Accrued Expenses and Other Current Liabilities
Accrued expenses and other current liabilities at December 31, 2023 and 2022 are summarized as follows:
December 31,
20232022
Accrued professional services and other$2,606 $5,834 
Accrued compensation and related benefits1,510 4,773 
Other accrued liabilities1,922 928 
Accrued severance, contract termination, and other charges4,013 — 
$10,051 $11,535 
v3.24.0.1
Warranties (Tables)
 12 Months Ended
Dec. 31, 2023
Guarantees and Product Warranties [Abstract]  
Schedule of Product Warranty Liability
The change in warranty liability for the years ended December 31, 2023 and 2022 is summarized as follows and included within accrued expenses and other current liabilities and other liabilities in the consolidated balance sheets:
Year ended December 31,
20232022
Balance at beginning of period$527 $44 
Accrual for warranties issued218 644 
Net changes in accrual related to pre-existing warranties(154)(7)
Warranty charges(182)(154)
Balance at end of period$409 $527 
v3.24.0.1
Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2023
Income Tax Disclosure [Abstract]  
Schedule of Provision for Income Taxes
The income tax provision for the years ended December 31, 2023 and 2022 is summarized as follows:
Year Ended December 31,
20232022
Current tax expense:
Federal$— $— 
State— — 
Total current tax expense$— $— 
Deferred tax (benefit) expense:
Federal$(25,328)$(34,296)
State— (40)
Valuation allowance25,328 34,336 
Total deferred tax expense$— $— 
Schedule of Deferred Taxes
The components of deferred taxes at December 31, 2023 and 2022 are summarized as follows:
December 31,
20232022
Deferred tax assets:
Federal net operating loss carryforwards$62,561 $48,186 
State net operating loss carryforwards491 491 
Operating lease obligation1,604 1,537 
Section 174 expenditures26,444 14,840 
R&D tax credit4,714 4,714 
Other3,235 3,148 
Intangible assets, net5,522 6,001 
Total deferred tax assets104,571 78,917 
Less: valuation allowance(102,803)(77,475)
Deferred tax assets, net of valuation allowance1,768 1,442 
Deferred tax liabilities:
Operating lease right of use asset, net1,485 1,359 
Property and equipment, net283 83 
Total deferred tax liabilities1,768 1,442 
Net deferred tax assets$— $— 
Schedule of Reconciliation of Taxes at Federal Statutory Rate to Provision for Income Taxes
The reconciliation of taxes at the federal statutory rate to the Company’s provision for income taxes for the years ended December 31, 2023 and 2022 is summarized as follows:
Year Ended December 31,
20232022
Provision at statutory rate of 21%$(25,937)$(32,205)
State tax expense— 492 
Stock options520 533 
Other89 865 
R&D tax credit— (4,021)
Change in valuation allowance25,328 34,336 
$— $— 
v3.24.0.1
Net Loss Per Share (Tables)
 12 Months Ended
Dec. 31, 2023
Earnings Per Share [Abstract]  
Schedule of Basic and Diluted Net Loss Per Share
The computation of basic and diluted net loss per share for the years ended December 31, 2023 and 2022 is summarized as follows (in thousands, except share and per share data):
Year Ended December 31,
20232022
Numerator:
Net loss attributable to common stockholders$(123,510)$(153,357)
Denominator:
Weighted average shares outstanding, basic and diluted181,411,069 175,400,486 
Net loss per share, basic and diluted$(0.68)$(0.87)
Schedule of Potential Common Shares
Potential common shares excluded from the computation of diluted net loss per share because including them would have had an anti-dilutive effect for the years ended December 31, 2023 and 2022 are summarized as follows:
Year Ended December 31,
20232022
Unexercised stock options522,971 2,541,439 
Unvested restricted stock units*3,385,073 4,105,673 
3,908,044 6,647,112 
* Potential common shares from unvested restricted stock units for the years ended December 31, 2023 and 2022 include 633,750 and 1,336,667 shares, respectively, where no accounting grant date has been established.
v3.24.0.1
Supplemental Cash Flow Information (Tables)
 12 Months Ended
Dec. 31, 2023
Supplemental Cash Flow Elements [Abstract]  
Schedule of Supplemental Cash Flow Information
Supplemental cash flow information for the years ended December 31, 2023 and 2022 is summarized as follows:
Year Ended December 31,
20232022
Cash paid for interest$— $— 
Cash paid for taxes$— $— 
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases$(2,470)$(1,921)
Right-of-use assets obtained in exchange for lease obligations$2,096 $— 
Schedule of Supplemental Disclosures of Noncash Financing Activities
Year Ended December 31,
20232022
Supplemental disclosure of noncash investing and financing activities:
Common stock issued for purchase of assets$— $16,115 
Acquisitions of property and equipment and intangible assets included in accounts payable and other$292 $59 
v3.24.0.1
Description of Organization and Business Operations and Basis of Presentation (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Accounting Policies [Abstract]      
Total equity $ 306,266 $ 423,574 $ 553,915
Cash and cash equivalents 12,881 $ 119,468 $ 258,445
Investments $ 278,500    
v3.24.0.1
Acquisitions and Disposals - Disposals Narrative (Details)
$ in Millions
 3 Months Ended
Nov. 07, 2023
USD ($)
employee
Dec. 31, 2023
USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]   Charged to Expense
Strategic Plan    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Workforce reduction (employee) | employee 175  
Workforce reduction percent 67.00%  
Total charges and expenses $ 20.4  
Charges and expenses incurred   $ 11.5
Expected remaining charges and expenses   $ 8.9
Strategic Plan | Employee Severance    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Total charges and expenses 1.2  
Strategic Plan | One-time Termination Benefits    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Total charges and expenses 0.7  
Strategic Plan | Contract Termination    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Total charges and expenses 14.5  
Strategic Plan | Non-cash Charges    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Total charges and expenses $ 4.0  
v3.24.0.1
Acquisitions and Disposals - Schedule of Changes in Plan Liabilities (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Restructuring Reserve [Roll Forward]    
Charged to Expense $ 11,474 $ 0
Strategic Plan    
Restructuring Reserve [Roll Forward]    
Beginning balance 0  
Charged to Expense 9,400  
Costs Paid or Settled (1,800)  
Ending balance 7,600 0
Strategic Plan | Employee severance and retention    
Restructuring Reserve [Roll Forward]    
Beginning balance 0  
Charged to Expense 1,200  
Costs Paid or Settled (100)  
Ending balance 1,100 0
Strategic Plan | Contract terminations    
Restructuring Reserve [Roll Forward]    
Beginning balance 0  
Charged to Expense 8,200  
Costs Paid or Settled (1,700)  
Ending balance $ 6,500 $ 0
v3.24.0.1
Acquisitions and Disposals - Acquisition Narrative (Details) - USD ($)
 1 Months Ended 12 Months Ended
Sep. 30, 2022
Dec. 31, 2023
Dec. 31, 2022
Asset Acquisition [Line Items]      
Goodwill $ 0    
Research and development   $ 82,240,000 $ 110,370,000
Acquisition      
Asset Acquisition [Line Items]      
Total consideration 32,300,000    
Payments to acquire productive assets $ 15,000,000    
Common stock shares issued (in shares) 5,500,000    
Common stock value $ 16,100,000    
Direct transaction costs 1,200,000    
Property and equipment $ 3,600,000    
Estimated useful life 5 years    
Research and development $ 28,800,000    
v3.24.0.1
Summary of Significant Accounting Policies - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2023
USD ($)
renewal_option
mi
Dec. 31, 2022
USD ($)
Sep. 30, 2023
USD ($)
May 31, 2023
Dec. 31, 2021
Lessee, Lease, Description [Line Items]          
Accounts receivable from customers $ 0.0 $ 1.1      
Accounts receivable allowance $ 0.0 0.1      
Maturity date (or less) 36 months        
Options to renew (at least) | renewal_option 1        
Lease extension       3 years 5 years
Warranty period extend 2 years        
Warrant extension, mileage | mi 200,000        
Marketing and advertising expense $ 1.3 $ 1.1      
Supplier          
Lessee, Lease, Description [Line Items]          
Letter of credit 7.9        
Corporate Headquarters Lessor          
Lessee, Lease, Description [Line Items]          
Letter of credit $ 0.7        
Disposals | Powertrain Business          
Lessee, Lease, Description [Line Items]          
Recorded amount of long lived assets     $ 4.2    
Estimated future cash flows     $ 4.4    
Minimum          
Lessee, Lease, Description [Line Items]          
Lease extension 1 year        
Maximum          
Lessee, Lease, Description [Line Items]          
Lease extension 5 years        
v3.24.0.1
Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Accounting Policies [Abstract]      
Cash and cash equivalents $ 12,881 $ 119,468 $ 258,445
Restricted cash included in prepaid expenses and other current assets 7,918 0 0
Restricted cash included in other assets 665 665 665
Total cash and cash equivalents $ 21,464 $ 120,133 $ 259,110
v3.24.0.1
Summary of Significant Accounting Policies - Schedule of Significant Customers (Details) - Significant Customers
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Customer A | Net accounts receivable    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 0.00% 82.00%
Customer A | Revenues    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 65.00% 60.00%
Customer C | Net accounts receivable    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 0.00% 12.00%
Customer B | Revenues    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 0.00% 10.00%
Customer G | Revenues    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 25.00% 0.00%
Customers | Net accounts receivable    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 0.00% 94.00%
Customers | Revenues    
Disaggregation of Revenue [Line Items]    
Concentration risk, percentage 90.00% 70.00%
v3.24.0.1
Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives (Details)
Dec. 31, 2023
Production machinery and equipment | Minimum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 2 years
Production machinery and equipment | Maximum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 7 years
Vehicles | Minimum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 3 years
Vehicles | Maximum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 7 years
Leasehold improvements  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 7 years
Demo fleet systems | Minimum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 2 years
Demo fleet systems | Maximum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 3 years
Furniture and fixtures  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 3 years
Computers and related equipment | Minimum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 3 years
Computers and related equipment | Maximum  
Public Utility, Property, Plant and Equipment [Line Items]  
Estimated useful life 7 years
v3.24.0.1
Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Disaggregation of Revenue [Line Items]    
Total product sales and other $ 672 $ 2,106
Hybrid systems and other    
Disaggregation of Revenue [Line Items]    
Total product sales and other 416 1,082
Class 8 semi-truck prepared for Hybrid system upfit    
Disaggregation of Revenue [Line Items]    
Total product sales and other $ 256 $ 1,024
v3.24.0.1
Investments - Schedule of Amortized Cost, Unrealized Gains and Losses, and Fair Value (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Held-to-maturity investments    
Amortized Cost $ 278,483 $ 302,308
Gross Unrealized Gains 590 112
Gross Unrealized Losses (499) (4,461)
Fair Value 278,574 297,959
Commercial paper    
Held-to-maturity investments    
Amortized Cost 35,218 36,675
Gross Unrealized Gains 18 2
Gross Unrealized Losses (10) (161)
Fair Value 35,226 36,516
U.S. government agency bonds    
Held-to-maturity investments    
Amortized Cost 27,602 12,441
Gross Unrealized Gains 56 6
Gross Unrealized Losses (186) (328)
Fair Value 27,472 12,119
State and municipal bonds    
Held-to-maturity investments    
Amortized Cost 15,262 40,104
Gross Unrealized Gains 1 28
Gross Unrealized Losses (48) (628)
Fair Value 15,215 39,504
Corporate bonds and notes    
Held-to-maturity investments    
Amortized Cost 200,401 213,088
Gross Unrealized Gains 515 76
Gross Unrealized Losses (255) (3,344)
Fair Value $ 200,661 $ 209,820
v3.24.0.1
Investments - Schedule of Investment Maturity (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Amortized Cost    
Due in one year or less $ 150,297 $ 193,740
Due after one year through five years 128,186 108,568
Amortized cost 278,483 302,308
Fair Value    
Due in one year or less 149,934 191,094
Due after one year through five years 128,640 106,865
Fair Value, Total held-to-maturity securities $ 278,574 $ 297,959
v3.24.0.1
Fair Value Measurements - Schedule of Assets and Liabilities That Are Measured at Fair Value on a Recurring Basis (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents $ 12,881 $ 119,468
Restricted cash 8,583 665
Held-to-maturity investments: 278,574 297,959
Total assets 300,038 418,092
Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 35,226 36,516
U.S. government agency bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 27,472 12,119
State and municipal bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 15,215 39,504
Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 200,661 209,820
Level I    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents 12,881 119,468
Restricted cash 8,583 665
Total assets 21,464 120,133
Level I | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level I | U.S. government agency bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level I | State and municipal bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level I | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level II    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents 0 0
Restricted cash 0 0
Total assets 278,574 297,959
Level II | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 35,226 36,516
Level II | U.S. government agency bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 27,472 12,119
Level II | State and municipal bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 15,215 39,504
Level II | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 200,661 209,820
Level III    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents 0 0
Restricted cash 0 0
Total assets 0 0
Level III | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level III | U.S. government agency bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level III | State and municipal bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: 0 0
Level III | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Held-to-maturity investments: $ 0 $ 0
v3.24.0.1
Inventory - Schedule of Inventory (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Inventory Disclosure [Abstract]    
Raw materials $ 0 $ 0
Work in process 0 0
Finished goods 0 74
Total inventory $ 0 $ 74
v3.24.0.1
Inventory - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Inventory Disclosure [Abstract]    
Inventory write-down $ 1,139 $ 5,641
v3.24.0.1
Capital Structure - Narrative (Details) - USD ($)
Dec. 31, 2023
Dec. 31, 2022
Equity [Abstract]    
Preferred stock, shares authorized 10,000,000  
Preferred stock, par value (in dollars per share) $ 0.0001  
Preferred stock, shares issued (in shares) 0 0
Preferred stock outstanding (in shares) 0 0
Share repurchase authorized $ 20,000,000  
v3.24.0.1
Capital Structure - Schedule of Common Stock Reserved (Details)
Dec. 31, 2023
shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Stock options issued and outstanding 522,971
Total 9,311,597
Authorized for future grant under 2020 Equity Incentive Plan  
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Authorized for future grant and issuance 6,988,626
Authorized for future issuance under the Hyliion Holdings Corp. Employee Stock Purchase Plan  
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Authorized for future grant and issuance 1,800,000
v3.24.0.1
Share-Based Compensation - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Oct. 01, 2020
Share-based Compensation (Details) [Line Items]      
Employee and nonemployee award vesting period 4 years    
Maximum term 10 years    
Options outstanding intrinsic value $ 300,000    
Exercisable intrinsic value 300,000    
Intrinsic value of options exercised $ 2,400,000 $ 2,400,000  
Employee Stock      
Share-based Compensation (Details) [Line Items]      
Contribution percent of base compensation 15.00%    
Purchase percent of market value 85.00%    
2016 Equity Incentive Plan      
Share-based Compensation (Details) [Line Items]      
Authorized for granted (in shares) 0    
Share-based compensation expense $ 0 100,000  
Unrecognized compensation cost related to share-based payments $ 0    
Weighted average remaining contractual term, exercisable 4 years 1 month 6 days    
2020 Equity Incentive Plan      
Share-based Compensation (Details) [Line Items]      
Authorized for granted (in shares)     12,200,000
Share-based compensation expense $ 6,200,000 6,900,000  
Unrecognized compensation cost related to share-based payments $ 4,900,000    
Weighted average remaining contractual term, exercisable 1 year 6 months    
2020 Equity Incentive Plan | RSUs      
Share-based Compensation (Details) [Line Items]      
Fair value of RSUs that vested in period $ 2,800,000 $ 1,700,000  
2020 Equity Incentive Plan | RSUs | Expected award forfeited in the first quarter of fiscal 2024      
Share-based Compensation (Details) [Line Items]      
RSU awards to be forfeited 800,000    
2020 Equity Incentive Plan | RSUs | Minimum      
Share-based Compensation (Details) [Line Items]      
Employee and nonemployee award vesting period 3 years    
2020 Equity Incentive Plan | RSUs | Maximum      
Share-based Compensation (Details) [Line Items]      
Employee and nonemployee award vesting period 4 years    
v3.24.0.1
Share-Based Compensation - Schedule of Share Option Activity 2016 (Details) - 2016 Equity Incentive Plan - $ / shares
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Number of Options      
Shares, Balance at beginning (in shares) 2,541,439 3,157,889  
Exercised (in shares) (1,936,018) (563,617)  
Forfeited (in shares) (82,450) (52,833)  
Shares, Balance at end (in shares) 522,971 2,541,439 3,157,889
Shares, Exercisable 473,239    
Weighted Average Exercise Price (in Dollars)      
Weighted average grant date fair value (in dollars per share) $ 0.15 $ 0.16  
Exercised (in dollars per share) 0.13 0.17  
Forfeited (in dollars per share) 0.22 0.20  
Weighted average grant date fair value (in dollars per share) 0.20 $ 0.15 $ 0.16
Weighted Average Exercise Price, Exercisable (in dollars per share) $ 0.20    
Weighted Average Remaining Contractual Term      
Weighted Average Remaining Contractual Term, Balance     6 years 7 months 6 days
Weighted Average Remaining Contractual Term, Balance 4 years 3 months 18 days 3 years 8 months 12 days  
Weighted average remaining contractual term, exercisable 4 years 1 month 6 days    
v3.24.0.1
Share-Based Compensation - Schedule of Share Option Activity 2020 (Details) - 2020 Equity Incentive Plan - $ / shares
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Number of Options    
Shares, Balance at beginning (in shares) 2,769,100 1,556,794
Granted (in shares) 2,192,900 2,504,939
Vested (in shares) (1,350,172) (470,426)
Forfeited (in shares) (860,505) (822,207)
Shares, Balance at end (in shares) 2,751,323 2,769,100
Weighted Average Exercise Price (in Dollars)    
Weighted average grant date fair value (in dollars per share) $ 5.51 $ 11.01
Granted (in dollars per share) 2.57 4.10
Vested (in dollars per share) 5.28 11.07
Forfeited (in dollars per share) 4.53 8.44
Weighted average grant date fair value (in dollars per share) $ 3.59 $ 5.51
Forfeited (in shares) 860,505 822,207
No established accounting grant date    
Number of Options    
Shares, Balance at beginning (in shares) 1,336,667 1,910,914
Granted (in shares) 25,000 204,167
Forfeited (in shares) (59,584) (130,000)
Shares, Balance at end (in shares) 633,750 1,336,667
Weighted Average Exercise Price (in Dollars)    
Forfeited (in shares) 59,584 130,000
v3.24.0.1
Leases - Narrative (Details) - extension
May 31, 2023
Dec. 31, 2021
Leases [Abstract]    
Number of consecutive term extensions 2 2
Lease extension 3 years 5 years
v3.24.0.1
Leases - Schedule of Operating Lease Costs and Finance Lease Costs (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Operating lease costs:    
Operating lease cost $ 2,239 $ 1,921
Short-term lease cost 508 199
Variable lease cost 682 622
Total operating lease costs $ 3,429 $ 2,742
v3.24.0.1
Leases - Schedule of Weighted-average Lease Terms and Discount Rates (Details)
Dec. 31, 2023
Dec. 31, 2022
Weighted-average remaining lease term:    
Operating leases 3 years 7 months 6 days 4 years 3 months 18 days
Weighted-average discount rate:    
Operating leases 8.70% 7.10%
v3.24.0.1
Leases - Schedule of Lease Liability Maturities for the Next Five Years (Details)
$ in Thousands
Dec. 31, 2023
USD ($)
Operating Leases  
2024 $ 1,497
2025 2,900
2026 2,989
2027 1,426
2028 306
Thereafter 0
Total minimum lease payments 9,118
Less: imputed interest (1,479)
Total lease obligations $ 7,639
v3.24.0.1
Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Property, Plant and Equipment [Line Items]    
Property and equipment, gross $ 16,811 $ 9,245
Less: accumulated depreciation (6,824) (3,639)
Total property and equipment, net 9,987 5,606
Production machinery and equipment    
Property, Plant and Equipment [Line Items]    
Property and equipment, gross 10,376 5,897
Vehicles    
Property, Plant and Equipment [Line Items]    
Property and equipment, gross 2,013 817
Leasehold improvements    
Property, Plant and Equipment [Line Items]    
Property and equipment, gross 2,236 1,002
Office furniture and fixtures    
Property, Plant and Equipment [Line Items]    
Property and equipment, gross 223 162
Computers and related equipment    
Property, Plant and Equipment [Line Items]    
Property and equipment, gross $ 1,963 $ 1,367
v3.24.0.1
Property and Equipment, Net - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Property, Plant and Equipment [Line Items]    
Depreciation expense $ 3.2 $ 1.1
Selling, General and Administrative Expenses    
Property, Plant and Equipment [Line Items]    
Depreciation expense 0.6 0.3
Research and Development Expense    
Property, Plant and Equipment [Line Items]    
Depreciation expense 1.7 $ 0.8
Exit And Termination Costs    
Property, Plant and Equipment [Line Items]    
Depreciation expense $ 0.9  
v3.24.0.1
Accrued Expenses and Other Current Liabilities - Schedule of accrued expenses and other current liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Accrued Liabilities and Other Liabilities [Abstract]    
Accrued professional services and other $ 2,606 $ 5,834
Accrued compensation and related benefits 1,510 4,773
Other accrued liabilities 1,922 928
Accrued severance, contract termination, and other charges 4,013 0
Total $ 10,051 $ 11,535
v3.24.0.1
Warranties - Schedule of Product Warranty Liability (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Movement in Standard Product Warranty Accrual [Roll Forward]    
Balance at beginning of period $ 527 $ 44
Accrual for warranties issued 218 644
Net changes in accrual related to pre-existing warranties (154) (7)
Warranty charges (182) (154)
Balance at end of period $ 409 $ 527
v3.24.0.1
Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Current tax expense:    
Federal $ 0 $ 0
State 0 0
Total current tax expense 0 0
Deferred tax (benefit) expense:    
Federal (25,328) (34,296)
State 0 (40)
Valuation allowance 25,328 34,336
Total deferred tax expense $ 0 $ 0
v3.24.0.1
Income Taxes - Schedule of Deferred Taxes (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Deferred tax assets:    
Federal net operating loss carryforwards $ 62,561 $ 48,186
State net operating loss carryforwards 491 491
Operating lease obligation 1,604 1,537
Section 174 expenditures 26,444 14,840
R&D tax credit 4,714 4,714
Other 3,235 3,148
Intangible assets, net 5,522 6,001
Total deferred tax assets 104,571 78,917
Less: valuation allowance (102,803) (77,475)
Deferred tax assets, net of valuation allowance 1,768 1,442
Deferred tax liabilities:    
Operating lease right of use asset, net 1,485 1,359
Property and equipment, net 283 83
Total deferred tax liabilities 1,768 1,442
Net deferred tax assets $ 0 $ 0
v3.24.0.1
Income Taxes - Schedule of Reconciliation of Taxes at Federal Statutory Rate to Provision for Income Taxes (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Income Tax Disclosure [Abstract]    
Provision at statutory rate of 21% $ (25,937) $ (32,205)
State tax expense 0 492
Stock options 520 533
Other 89 865
R&D tax credit 0 (4,021)
Change in valuation allowance 25,328 34,336
Total $ 0 $ 0
v3.24.0.1
Income Taxes - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Income Taxes [Line Items]    
R&D tax credit $ 0.1  
Net operating loss 2.0  
2037    
Income Taxes [Line Items]    
R&D tax credit 4.7  
Federal    
Income Taxes [Line Items]    
Net operating loss carryforwards 297.9 $ 229.5
Federal | 2036    
Income Taxes [Line Items]    
Net operating loss carryforwards 10.5  
Federal | Indefinite    
Income Taxes [Line Items]    
Net operating loss carryforwards 287.4  
State and Local Jurisdiction    
Income Taxes [Line Items]    
Net operating loss carryforwards $ 12.5 $ 12.5
v3.24.0.1
Commitments and Contingencies (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]    
Grant funding received included within other current accrued liabilities $ 1.1  
Grant funding received included within other noncurrent liabilities   $ 0.9
v3.24.0.1
Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Numerator:    
Net loss attributable to common stockholders, basic $ (123,510) $ (153,357)
Net loss attributable to common stockholders, diluted $ (123,510) $ (153,357)
Denominator:    
Weighted-average shares outstanding, basic (in shares) 181,411,069 175,400,486
Weighted-average shares outstanding, diluted (in shares) 181,411,069 175,400,486
Net loss per share, basic (in dollars per share) $ (0.68) $ (0.87)
Net loss per share, diluted (in dollars per share) $ (0.68) $ (0.87)
v3.24.0.1
Net Loss Per Share - Schedule of Potential Common Shares (Details) - shares
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Common shares excluded from computation of diluted Net (loss) income per share 3,908,044 6,647,112
Anti-dilutive effect. Potential common shares from unvested restricted stock 633,750 1,336,667
Unexercised stock options    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Common shares excluded from computation of diluted Net (loss) income per share 522,971 2,541,439
Unvested restricted stock units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Common shares excluded from computation of diluted Net (loss) income per share 3,385,073 4,105,673
v3.24.0.1
Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Supplemental Cash Flow Elements [Abstract]    
Cash paid for interest $ 0 $ 0
Cash paid for taxes 0 0
Cash paid for amounts included in the measurement of lease liabilities:    
Operating cash flows from operating leases (2,470) (1,921)
Right-of-use assets obtained in exchange for lease obligations $ 2,096 $ 0
v3.24.0.1
Supplemental Cash Flow Information - Schedule of Supplemental Disclosures of Noncash Financing Activities (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Supplemental Cash Flow Elements [Abstract]    
Common stock issued for purchase of assets $ 0 $ 16,115
Acquisitions of property and equipment and intangible assets included in accounts payable and other $ 292 $ 59
v3.24.0.1
Retirement Plan (Details)
 12 Months Ended
Dec. 31, 2023
Retirement Benefits [Abstract]  
Participants minimum required age limit of plan 21 years