Aspen Aerogels (ASPN) 10-Q 2 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	May 01, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Trading Symbol	ASPN
Entity Registrant Name	ASPEN AEROGELS, INC.
Entity Central Index Key	0001145986
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		76,161,210
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-36481
Entity Tax Identification Number	04-3559972
Entity Address, Address Line One	30 Forbes Road
Entity Address, Address Line Two	Building B
Entity Address, State or Province	MA
Entity Address, City or Town	Northborough
Entity Address, Postal Zip Code	01532
City Area Code	508
Local Phone Number	691-1111
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.00001 per share
Security Exchange Name	NYSE
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 101,461	$ 139,723
Restricted cash	157	248
Accounts receivable, net of allowances of $217 and $230	84,029	69,995
Inventories	45,750	39,189
Prepaid expenses and other current assets	23,708	17,176
Total current assets	255,105	266,331
Property, plant and equipment, net	422,736	417,227
Operating lease right-of-use assets	16,824	17,212
Other long-term assets	3,324	2,278
Total assets	697,989	703,048
Current liabilities:
Accounts payable	44,713	51,094
Accrued expenses	12,762	22,811
Deferred revenue	3,130	2,316
Finance obligation for sale and leaseback transactions	1,206
Operating lease liabilities	1,769	1,874
Total current liabilities	63,580	78,095
Convertible note - related party	118,030	114,992
Finance obligation for sale and leaseback transactions long-term	3,556
Operating lease liabilities long-term	21,620	21,906
Total liabilities	206,786	214,993
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 5,000,000 shares authorized, no shares issued and outstanding at March 31, 2024 and December 31, 2023
Common stock, $0.00001 par value; 250,000,000 shares authorized, 76,077,929 and 76,503,151 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	0	0
Additional paid-in capital	1,166,640	1,161,657
Accumulated deficit	(675,437)	(673,602)
Total stockholders’ equity	491,203	488,055
Total liabilities and stockholders’ equity	$ 697,989	$ 703,048

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Allowance for accounts receivable and contract assets	$ 217	$ 230
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	76,077,929	76,503,151
Common stock, shares outstanding	76,077,929	76,503,151

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 94,501	$ 45,586
Cost of revenue	59,358	40,500
Gross profit	35,143	5,086
Operating expenses:
Research and development	4,489	4,099
Sales and marketing	8,303	7,713
General and administrative	17,213	12,182
Total operating expenses	32,707	23,994
Income (loss) from operations	2,436	(18,908)
Other income (expense)
Interest expense, convertible note - related party	(3,038)	(275)
Interest income (expense)	(477)	2,387
Total other income (expense)	(3,515)	2,112
Loss before income tax expense	(1,079)	(16,796)
Income tax expense	(756)
Net loss	$ (1,835)	$ (16,796)
Net loss per share:
Basic	$ (0.02)	$ (0.24)
Diluted	$ (0.02)	$ (0.24)
Weighted-average common shares outstanding:
Basic	75,762,893	69,162,739
Diluted	75,762,893	69,162,739

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2022	$ 447,435		$ 1,075,226	$ (627,791)
Beginning balance, shares at Dec. 31, 2022		69,994,963
Net loss	(16,796)			(16,796)
Stock compensation expense	2,267		2,267
Vesting of restricted stock units	(385)		(385)
Vesting of restricted stock units, shares		71,643
Proceeds from employee stock option exercises	21		21
Proceeds from employee stock option exercises, shares		2,554
Ending balance at Mar. 31, 2023	432,542		1,077,129	(644,587)
Ending balance, shares at Mar. 31, 2023		70,069,160
Beginning balance at Dec. 31, 2023	488,055		1,161,657	(673,602)
Beginning balance, shares at Dec. 31, 2023		76,503,151
Net loss	(1,835)			(1,835)
Stock compensation expense	2,532		2,532
Issuance costs from private placement of common stock	(28)		(28)
Vesting of restricted stock units	(1,081)		(1,081)
Vesting of restricted stock units, shares		118,289
Cancellation of restricted stock	2,174		2,174
Cancellation of restricted stock, shares		(679,797)
Proceeds from employee stock option exercises	1,386		1,386
Proceeds from employee stock option exercises, shares		136,286
Ending balance at Mar. 31, 2024	$ 491,203		$ 1,166,640	$ (675,437)
Ending balance, shares at Mar. 31, 2024		76,077,929

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (1,835,000)	$ (16,796,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	5,786,000	2,704,000
Accretion of interest on convertible note - related party	2,810,000
Amortization of debt discount due to modification of convertible note - related party	219,000	266,000
Deferred financing costs written off	1,709,000
Provision for bad debt		99,000
Stock-compensation expense	4,706,000	2,267,000
Impairment of property, plant and equipment	6,039,000	0
Reduction in the carrying amount of operating lease right-of-use assets	574,000	632,000
Changes in operating assets and liabilities:
Accounts receivable	(14,034,000)	9,971,000
Inventories	(6,561,000)	(4,469,000)
Prepaid expenses and other assets	(9,359,000)	(5,097,000)
Accounts payable	2,148,000	(5,516,000)
Accrued expenses	(10,289,000)	(6,240,000)
Deferred revenue	814,000	(1,872,000)
Operating lease liabilities	(485,000)	(609,000)
Net cash used in operating activities	(17,749,000)	(24,651,000)
Cash flows from investing activities:
Capital expenditures	(25,863,000)	(49,378,000)
Net cash used in investing activities	(25,863,000)	(49,378,000)
Cash flows from financing activities:
Proceeds from employee stock option exercises	1,386,000	21,000
Proceeds from sale and leaseback transactions	4,982,000
Payments made for employee restricted stock tax withholdings	(1,081,000)	(385,000)
Fees and issuance costs from private placement of common stock	(28,000)
Net cash provided by (used in) financing activities	5,259,000	(364,000)
Net (decrease) increase in cash, cash equivalents and restricted cash	(38,353,000)	(74,393,000)
Cash, cash equivalents and restricted cash at beginning of period	139,971,000	282,561,000
Cash, cash equivalents and restricted cash at end of period	101,618,000	208,168,000
Supplemental disclosures of cash flow information:
Interest paid	187,000	0
Supplemental disclosures of non-cash activities:
Right-of-use assets obtained in exchange for new operating lease liabilities	94,000
Capitalized interest		2,561,000
Changes in accrued capital expenditures	(8,529,000)	3,610,000
Convertible Note [Member]
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of convertible note issuance costs	$ 9,000	$ 9,000

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (1,835)	$ (16,796)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On February 26, 2024 , Donald R. Young , our President, Chief Executive Officer , and member of our board of directors, adopted a trading plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. The plan provides for the sale of up to 691,124 shares at specific market prices, subject to specified limitations, during pre-determined sale periods. The plan was established for the purposes of facilitating the exercise and subsequent sale of stock options with a ten-year contractual life that are due to expire between September 2024 and December 2025 (the “Options”), by facilitating the sale of shares solely to raise sufficient proceeds to cover the exercise cost and taxes associated with the exercise of the Options. The plan expires on the earlier of (i) the date all of the shares under the plan have been sold and (ii) December 11, 2025 . Except as disclosed above, none of our directors or executive officers adopted , modified or terminated any contract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any “non-Rule 10b5-1 trading arrangement” as such term is defined in Item 408(a) of Regulation S-K, during the fiscal quarter ended March 31, 2024
Donald R. Young
Trading Arrangements, by Individual
Name	Donald R. Young
Title	President, Chief Executive Officer
Adoption Date	February 26, 2024
Arrangement Duration	118 days
Aggregate Available	691,124
Trd Arr Expiration Date	December 11, 2025
Other Directors or Executive Officers
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arr Modified Flag	false
Non Rule10B51 Arr Modified Flag	false

Description of Business and Bas

Description of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	(1) Description of Business and Basis of Presentation Nature of Business Aspen Aerogels, Inc. (the Company) is an aerogel technology company that designs, develops and manufactures innovative, high-performance aerogel insulation used primarily in the energy industrial and sustainable insulation materials markets. In addition, the Company has introduced a line of aerogel thermal barriers for use in battery packs in the electric vehicle market. The Company is also developing applications for its aerogel technology in the battery materials and a number of other high-potential markets. The Company maintains its corporate offices in Northborough, Massachusetts. The Company has three wholly owned subsidiaries: Aspen Aerogels Rhode Island, LLC, Aspen Aerogels Germany, GmbH and Aspen Aerogels Georgia, LLC. Additionally, we engaged Prodensa Servicios de Consultora to establish OPE Manufacturer Mexico S de RL de CV, a maquiladora located in Mexico, (“OPE”) which manufactures thermal barrier PyroThin products and operates an automated fabrication facility for PyroThin. OPE is currently owned by Prodensa, which charges a management fee. There is an option for OPE to be purchased by the Company after a period of 18 months. During the period between inception and the exercise of the purchase option, OPE operations are consolidated within the Company financial statements. Liquidity During the three months ended March 31, 2024, the Company incurred a net loss of $ 1.8 million, used $ 17.7 million of cash in operations and used $ 25.9 million of cash for capital expenditures. The Company had unrestricted cash and cash equivalents of $ 101.5 million as of March 31, 2024. In November 2022, the Company entered into a loan agreement (the GM Loan Agreement) with General Motors Holdings LLC (GM), an entity affiliated with General Motors LLC, which provides for a multi-draw senior secured term loan (the GM Loan) in an aggregate principal amount of up to $ 100.0 million, available to the Company on a delayed draw basis beginning January 1, 2023 to September 30, 2023 , subject to certain conditions precedent to funding. In September 2023, the Company amended the GM Loan Agreement to (i) extend the draw period for the GM Loan to a period beginning on the date that is twelve months prior to the date agreed upon by the Company and GM for the start of production at an aerogel manufacturing facility in Bulloch County, Georgia (the Plant) and ending on March 31, 2024 (or any later date approved in writing by GM at its sole discretion); (ii) extend the maturity date of the GM Loan from March 31, 2025 to September 30, 2025; and (iii) add financial covenants measured starting from the fiscal quarter ending December 31, 2024 and at the end of each fiscal quarter thereafter. As of March 31, 2024, the Company has not drawn, and no longer has the ability to draw on the GM Loan. The associated unamortized deferred financing costs of $ 1.7 million were written off to interest expense upon the expiration of the draw period. In January 2024 , the Company entered i nto a sale and leaseback arrangement, pursuant to which the Company sold certain equipment to an equipment leasing company for a one-time cash payment of $ 5.0 million and leased back such equipment from the leasing company. The associated monthly lease rents will be paid over the lease term of three years . The Company is increasing investment in the research and development of next-generation aerogel products and manufacturing process technologies. In addition, the Company has developed a number of promising aerogel products and technologies for the electric vehicle market. The Company believes that the commercial potential for the Company’s products and technology in the electric vehicle market is significant. Accordingly, the Company is hiring additional personnel, incurring additional operating expenses, incurring significant capital expenditures to expand aerogel manufacturing capacity and automated thermal barrier fabrication operations, and enhancing research and development resources, among other items. The Company expects its existing cash balance will be sufficient to support current operating requirements, current research and development activities and the initial capital expenditures required to support the evolving commercial opportunity in the electric vehicle market and other strategic business initiatives. However, the Company plans to supplement its cash balance with equity financings, debt financings, equipment leasing, sale and leaseback transactions, c ustomer prepayments, or government grant and loan programs to provide the additional capital necessary to purchase the capital equipment, construct the new facilities, establish the operations and complete the aerogel capacity expansions required to support these evolving commercial opportunities and strategic business initiatives. Unaudited Interim Financial Information The accompanying unaudited interim consolidated financial statements include the accounts of the Company and have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and disclosures normally included in the consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and accompanying notes in our Annual Report on Form 10-K for the year ended December 31, 2023 (the Annual Report), filed with the U.S. Securities and Exchange Commission on March 7, 2024. In the opinion of the Company’s management, the unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments that are of a normal recurring nature and necessary for the fair statement of the Company’s financial position as of March 31, 2024 and the results of its operations and stockholders’ equity for the three months ended March 31, 2024 and 2023 and the cash flows for the three-month periods then ended. The Company has evaluated subsequent events through the date of this filing. The Company’s results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or any other period.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Significant Accounting Policies	(2) Significant Accounting Policies Please refer to "Note 2. Summary of Basis of Presentation and Significant Accounting Policies," to the Company's consolidated financial statements from the Annual Report for the discussion of the Company's significant accounting policies. Use of Estimates The preparation of the consolidated financial statements requires the Company to make a number of estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include allowances for doubtful accounts, sales returns and allowances, product warranty costs, inventory valuation, the carrying amount of property and equipment, right-of-use assets, lease liabilities, stock-based compensation, and deferred income taxes. The Company evaluates its estimates and assumptions on an on-going basis using historical experience and other factors, including current economic conditions, which are believed to be reasonable under the circumstances. Management adjusts such estimates and assumptions when facts and circumstances warrant. Illiquid credit markets, volatile equity markets and declines in business investment can increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods. Restricted Cash As of March 31, 2024, the Company had $ 0.2 million of restricted cash to support its outstanding letters of credit. Concentration of Credit Risk Financial instruments, which potentially expose the Company to concentrations of credit risk, consist principally of accounts receivable. The Company’s customers are primarily insulation distributors, insulation contractors, insulation fabricators and select energy and automotive end-users located throughout the world. The Company performs ongoing credit evaluations of its customers’ financial condition and generally requires no collateral to secure accounts receivable. The Company maintains an allowance for doubtful accounts based on its assessment of the collectability of accounts receivable. The Company reviews the allowance for doubtful accounts quarterly. During both the three months ended March 31, 2024 and 2023, the Company recorded an increase for estimated customer uncollectible accounts receivable of less than $ 0.1 million. For the three months ended March 31, 2024 and 2023 , two customers represented 64 % and 45 % of total revenue, respectively. At March 31, 2024 , the Company had one customer which accounted for 64 % of accounts receivable. At December 31, 2023, the Company had two customers which accounted for 60 % and 6 % of accounts receivable, respectively. Revenue Recognition The Company recognizes revenue in accordance with Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606). See note 3 for further details. Warranty The Company provides warranties for its products and records the estimated cost within cost of revenue in the period that the related revenue is recorded. The Company’s standard warranty period for energy industrial products extends to one year from the date of shipment. This standard warranty provides that the Company’s products will be free from defects in material and workmanship, and will, under normal use, conform to the specifications for the product. The Company’s thermal barrier products provide quality and warranty provisions customary in the automotive industry. The Company recorded warranty expense related to its thermal barrier products of $ 0.2 million during the three months ended March 31, 2024 and less than $ 0.1 million during the three months ended March 31, 2023 . Sale and Leaseback Accounting The Company has entered into sale and leaseback transactions for certain equipment within its plants. Due to the Company not meeting criteria to account for the transfer of the assets as a sale, sale accounting is precluded. Accordingly, the Company uses the financing method to account for these transactions. Under the financing method of accounting for a sale and leaseback, the Company does not derecognize the assets and does not recognize as revenue any of the sale proceeds received from the lessor that contractually constitutes payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as finance obligations and leaseback payments made by the Company are allocated between interest expense and a reduction to the finance obligation. Interest on the finance obligation is calculated using the Company’s incremental borrowing rate at the inception of the arrangement on the outstanding finance obligation. Recently Issued Accounting Standards From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies. Recently issued standards typically do not require adoption until a future effective date. Prior to their effective date, the Company evaluates the pronouncements to determine the potential effects of adoption to its consolidated financial statements. Standards Implemented Since December 31, 2023 The Company has not implemented any accounting standards that had a material impact on its consolidated financial statements during the three months ended March 31, 2024. Standards to be Implemented In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2023-07 Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures to enhance disclosures about significant segment expenses. This ASU is effective for the Company’s fiscal year 2024 and interim periods in fiscal year 2025. Early adoption is permitted. The Company is currently evaluating segment expense disclosures related to its annual report for fiscal year 2024. In December 2023, the FASB issued ASU 2023-09 Income Taxes (Topic 740) Improvements to Income Tax Disclosures that requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. This ASU is effective for the Company’s fiscal year 2025. Early adoption is permitted. The Company is currently evaluating income tax disclosures related to its annual report for fiscal year 2025. Although there are several other new accounting pronouncements issued by the FASB, the Company does not believe any of these accounting pronouncements had or will have a material impact on its Consolidated Financial Statements. The Company believes that the impact of recently issued accounting standards that are not yet effective will not have a material impact on its consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	(3) Revenue from Contracts with Customers Revenue Recognition Revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract with a customer; (ii) identification of the performance obligations in the contract; (iii) determination of the transaction price; (iv) allocation of the transaction price to the separate performance obligations in the contract; and (v) recognition of the revenue associated with performance obligations as they are satisfied. The Company applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price based on the estimated relative standalone-selling prices of the promised products or services underlying each performance obligation. The Company determines standalone-selling prices based on the price at which the performance obligation is sold separately. If the standalone-selling price is not observable through past transactions, the Company estimates the standalone-selling price considering available information such as market conditions and internally approved pricing guidelines related to the performance obligations. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. When determining the transaction price of a contract, an adjustment is made if payment from a customer occurs either significantly before or significantly after performance, resulting in a significant financing component. Applying the practical expedient in paragraph ASC 606-10-32-18, the Company does not assess whether a significant financing component exists if the period between when the Company performs its obligations under the contract and when the customer pays is one year or less. The Company did not have any contracts outstanding at December 31, 2023 and did not enter into any contracts during the three months ended March 31, 2024 that contained a significant financing component. The Company records deferred revenue for product sales when (i) the Company has delivered products, but other revenue recognition criteria have not been satisfied, or (ii) payments have been received in advance of the completion of required performance obligations. Energy Industrial The Company generally enters into contracts containing one type of performance obligation. For a majority of the contracts, the Company recognizes revenue at a point in time when transfer of control of the products is passed to the customer, which is generally upon delivery according to contractual shipping terms within customer purchase orders. For a limited number of customer arrangements for customized products with no alternative use to the Company and an enforceable right to payment for progress completed to date, the Company recognizes revenue over time using units of production to measure progress toward satisfying the performance obligations. Units of production represent work performed as we do not generate significant work in process and thereby best depicts the transfer of control to the customer. Customer invoicing terms for contracts for which revenue is recognized under the over time methodology are typically based on certain milestones within the production and delivery schedule. The timing of revenue recognition is assessed on a contract-by-contract basis. The Company also enters into rebate agreements with certain customers. These agreements may be considered an additional performance obligation of the Company or variable consideration within a contract. Rebates are recorded as a reduction of revenue in the period the related revenue is recognized. A corresponding liability is recorded as a component of deferred revenue on the consolidated balance sheets. These arrangements are primarily based on the customer attaining contractually specified sales volumes. The Company estimates the amount of its sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related revenue is recognized. The Company currently estimates return liabilities using historical rates of return, current quarter credit sales, and specific items of exposure on a contract-by-contract basis. Sales return reserves were approximately $ 0.2 million as of March 31, 2024 and December 31, 2023. Thermal Barriers The Company supplies fabricated, multi-part thermal barriers for use in battery packs in the electric vehicle market. These thermal barriers are customized to meet customer specifications. Although thermal barrier products are customized with no alternative use to the Company, the Company does not always have an enforceable right to payment. Under the provisions of ASC 606, the Company recognizes revenue at a point in time when transfer of the control of the products is passed to the customer according to the terms of the contract, including under bill and hold arrangements. The timing of revenue recognition is assessed on a contract-by-contract basis. Shipping and Handling Costs Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as fulfillment costs and are included in the cost of product revenue. The associated amount of revenue recognized includes the consideration to which the Company expects to be entitled to receive in exchange for incurring these shipping and handling costs. Disaggregation of Revenue In the following tables, revenue is disaggregated by primary geographical region and source of revenue: Three Months Ended March 31, 2024 2023 U.S. International Total U.S. International Total (In thousands) Geographical region Asia $ — $ 7,213 $ 7,213 $ — $ 11,784 $ 11,784 Canada — 1,868 1,868 — 324 324 Europe — 9,361 9,361 — 5,412 5,412 Latin America — 15,371 15,371 — 1,624 1,624 U.S. 60,688 — 60,688 26,442 — 26,442 Total revenue $ 60,688 $ 33,813 $ 94,501 $ 26,442 $ 19,144 $ 45,586 Source of revenue Energy industrial $ 14,033 $ 15,049 $ 29,082 $ 16,504 $ 17,371 $ 33,875 Thermal barrier 46,655 18,764 65,419 9,938 1,773 11,711 Total revenue $ 60,688 $ 33,813 $ 94,501 $ 26,442 $ 19,144 $ 45,586 Contract Balances The following table presents changes in the Company’s contract liabilities during the three months ended March 31, 2024: Balance at Additions Deductions Balance at (In thousands) Contract liabilities Deferred revenue Energy industrial $ 2,316 $ 2,941 $ ( 2,127 ) $ 3,130 Total contract liabilities $ 2,316 $ 2,941 $ ( 2,127 ) $ 3,130 During the three months ended March 31, 2024, the Company recognized $ 1.2 million of revenue that was included in deferred revenue as of December 31, 2023. A contract asset is recorded when the Company satisfies a performance obligation by transferring a promised good or service and has earned the right to consideration from its customer. These assets may represent a conditional right to consideration and are included within accounts receivable and other current assets on the consolidated balance sheets. A contract liability is recorded when consideration is received, or such consideration is unconditionally due, from a customer prior to transferring goods or services under the terms of the contract. Contract liabilities are recognized as revenue after control of the products or services is transferred to the customer and all revenue recognition criteria have been met.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories	(4) Inventories Inventories consist of the following: March 31, December 31, 2024 2023 (In thousands) Raw materials $ 19,190 $ 24,735 Work in process 13,936 7,936 Finished goods 12,624 6,518 Total $ 45,750 $ 39,189

Property, Plant and Equipment,

Property, Plant and Equipment, Net	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	(5) Property, Plant and Equipment, Net Property, plant and equipment consist of the following: March 31, December 31, Useful 2024 2023 life (In thousands) Construction in progress $ 322,030 $ 314,695 — Buildings 25,985 25,473 30 years Machinery and equipment 187,075 185,339 3 - 10 years Computer equipment and software 9,631 9,495 3 years Leasehold improvements 23,472 23,514 Shorter of useful life or lease term Total 568,193 558,516 Accumulated depreciation ( 145,457 ) ( 141,289 ) Property, plant and equipment, net $ 422,736 $ 417,227 Depreciation expense was $ 5.8 million and $ 2.7 million for the three months ended March 31, 2024 and 2023, respectively. The Company recorded impairment charges of approximately $ 6.0 million during the three months ended March 31, 2024 for equipment that will no longer be needed in manufacturing following customer directed engineering changes to a part it manufactures and for other property, plant and equipment that have become obsolete following development of new and more efficient equipment. The impairment charges of $6.0 million during the three months ended March 31, 2024 consist of $3.3 million impairment included in cost of revenue and $2.7 million included in impairment of equipment under development on the Company's consolidated statement of operations. There were no impairments of property, plant and equipment during the three months ended March 31, 2023. The construction in progress balance at March 31, 2024 and December 31, 2023 included engineering designs and construction costs, and capitalized interest totaling $ 296.7 million and $ 288.5 million, respectively, for a planned aerogel manufacturing facility in Bulloch County, Georgia. The Company incurred $ 8.8 million in capitalized interest for the construction in progress in Bulloch County, Georgia. The Company incurred $ 0.0 million and $ 2.6 million in capitalized interest for the three months ended March 31, 2024 and 2023 , respectively.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses	(6) Accrued Expenses Accrued expenses consist of the following: March 31, December 31, 2024 2023 (In thousands) Employee compensation $ 5,710 $ 16,876 Other accrued expenses 7,052 5,935 Total $ 12,762 $ 22,811

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	(7) Related Party Transactions Convertible Note During the year ended December 31, 2022, the Company issued a $ 100.0 million aggregate principal amount convertible note to Wood River Capital, LLC, an entity affiliated with Koch Disruptive Technologies, LLC (the 2022 Convertible Note), for the planned manufacturing facility in Bulloch County, Georgia. Refer to note 8 for more information. During the three months ended March 31, 2024, the Company incurred $ 2.8 million of interest from the 2022 Convertible Note. Other The Company had $ 2.8 million in accounts payable as o f December 31, 2023, due to an entity affiliated with Koch Disruptive Technologies, LLC (Koch) for project management service. On March 27, 2024, we entered into a Settlement and Release Agreement with the affiliate of Koch to settle the accounts payable for $ 1.2 million, which was outstanding as of March 31, 2024 .

Convertible Note - Related Part

Convertible Note - Related Party	3 Months Ended
	Mar. 31, 2024
Convertible Notes [Abstract]
Convertible Note - Related Party	(8) Convertible Note – Related Party 2022 Convertible Note On February 15, 2022 , the Company entered into a note purchase agreement (the Note Purchase Agreement) with Wood River Capital LLC, an entity affiliated with Koch, relating to the issuance and sale to Koch of the 2022 Convertible Note in the aggregate principal amount of $ 100.0 million. The transactions contemplated by the Note Purchase Agreement closed on February 18, 2022 (the Issue Date). The maturity date of the 2022 Convertible Note is February 18, 2027 , subject to earlier conversion, redemption, or repurchase. The 2022 Convertible Note is a senior unsecured obligation of the Company and ranks equal in right of payment to all senior unsecured indebtedness of the Company and will rank senior in right of payment to any indebtedness that is contractually subordinated to the 2022 Convertible Note. In accordance with ASU 2020-06, the 2022 Convertible Note is accounted for as a single unit of account and consists of the following: March 31, December 31, 2024 2023 (In thousands) Convertible note, principal $ 100,000 $ 100,000 Payment in-kind 18,318 18,318 Accrued interest 2,810 - Discount on convertible note, net of accumulated amortization ( 2,990 ) ( 3,209 ) Debt issuance costs, net of accumulated amortization ( 108 ) ( 117 ) Convertible note $ 118,030 $ 114,992 The 2022 Convertible Note does not have current observable inputs such as recent trading prices (Level 1) and is measured at fair value using a combination of option pricing and discounted cash flow models and incorporate management’s assumptions for stock price, volatility and risk rate. In general, fair values determined by Level 1 inputs utilize observable inputs such as quoted prices in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are either directly or indirectly observable, such as quoted prices for similar instruments in active markets, interest rates and yield curves. Fair values determined by Level 3 inputs utilize unobservable data points in which there is little or no market data, which require the Company to develop its own assumptions for the asset or liability. The Company estimated the fair value of the 2022 Convertible Notes is approximately $ 118.7 million as of March 31, 2024. However, as the Company has not elected to utilize the fair value option, it is carried at amortized cost of $ 118.0 million. Contractual Interest Rates The 2022 Convertible Note was issued at par and bears interest at the Secured Overnight Financing Rate (SOFR) plus 5.50 % per annum if interest is paid in cash, or, if interest is paid in-kind as an increase in the principal amount of the outstanding note, at the SOFR plus 6.50 % per annum. Under the terms of the 2022 Convertible Note, SOFR has a floor of 1 % and a cap of 3 %. Interest on the 2022 Convertible Note is payable semi-annually in arrears on June 30 and December 30. The Company, at its option, is permitted to settle each semi-annual interest payment in cash, in-kind, or any combination thereof. It is expected that the Notes will mature on February 18, 2027 , subject to earlier conversion, redemption or repurchase. The Company elected to repay the contractual interest due on June 30, 2022, December 30, 2022, June 30, 2023, and December 30, 2023 in-kind as an increase to the principal amount of $ 2.9 million, $ 4.9 million, $ 5.1 million, and $ 5.4 million, respectively. The contractual interest attributable to the 2022 Convertible Note was recorded as an addition to the convertible note – related party balance on the condensed consolidated balance sheets. Accrued interest was $ 2.8 million as of March 31, 2024, of which debt issuance costs, net of accumulated amortization is $ 0.1 million. The effective interest rate approximated the contract interest rate for the three months ended March 31, 2024 . The Company amortized $ 1.1 million of the $ 4.1 million discount on the convertible note as of March 31, 2024 utilizing an effective interest rate of 10.7 %. Conversion Rights On November 28, 2022, the Company entered into an amendment to the 2022 Convertible Note to reduce the initial Conversion Price by $ 5.00 per share from $ 34.936625 per share to $ 29.936625 per share, by increasing the initial Conversion Rate from 28.623257 shares per $ 1,000 of Capitalized Principal Amount to 33.400100 shares per $ 1,000 of Capitalized Principal Amount under the Convertible Note. Accordingly, the 2022 Convertible Note is convertible at the option of the holder at any time prior to the business day immediately preceding the maturity date at an initial conversion rate of 33.400100 shares of the Company’s common stock per $ 1,000 of capitalized principal. The effective conversion price is approximately $ 29.936625 per share (the Conversion Price). The Conversion Price is subject to adjustment upon the occurrence of certain dilutive events such as stock splits and combinations, stock dividends, mergers and spin-off. As of March 31, 2024, 4,045,687 shares of the Company’s common stock were issuable upon conversion of the 2022 Convertible Note. The Company has the right to settle conversions in shares of common stock, cash, or any combination thereof. If the closing price per share of the Company’s common stock on the New York Stock Exchange is at least 130 % of the Conversion Price for 20 consecutive trading days , the Company may elect to convert the principal and accrued interest owing under the Notes, plus a make-whole amount equal to the sum of the present values of the remaining interest payments that would have otherwise been payable from the date of such conversion, redemption or repurchase, as applicable, through maturity (the Make-Whole Amount), into the Company’s common stock at the Conversion Price. Optional Redemption The 2022 Convertible Note is redeemable at the Company’s option at any time and in the event that the volume weighted average price of the Company’s common stock for the 10 trading days immediately preceding the date on which the Company provides the redemption notice has been at least 130 % of the Conversion Price then in effect at a redemption price of 100 % of the principal amount, plus accrued and unpaid interest (excluding the redemption date), plus the Make-Whole Amount. Contingent Redemption Upon the occurrence of certain fundamental changes described in the Indenture (each, a Fundamental Change), the Holder of the Note may require that the Company repurchase all or part of the principal amount of the Note at a purchase price of 100 % of the principal amount of such Note, plus accrued and unpaid interest to, but excluding, the Fundamental Change repurchase date, plus the Make-Whole Amount. The Indenture includes customary “events of default,” which may result in the acceleration of the maturity of the Note. Embedded Derivatives The Company determined that the Make-Whole feature of the 2022 Convertible Note requires bifurcation in accordance with Accounting Standards Codification 815, Derivatives and Hedging (ASC 815). Accordingly, the Company must separately account for the feature at fair value with changes in fair value reported in current period earnings. The fair value of the Make-Whole was determined to be immaterial as of February 18, 2022 and March 31, 2024 .

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	(9) Commitments and Contingencies Cloud Computing Agreement The Company is party to a cloud computing agreement that is a service contract for enterprise resource planning software. During the quarter ended March 31, 2024 , the amortization period was adjusted to three years . The capitalized implementation costs are classified on the consolidated balance sheets as follows: March 31, December 31, 2024 2023 (In thousands) Cloud computing costs included in other current assets $ 420 $ 420 Cloud computing costs included in other assets 1,957 1,590 Amortization of cloud computing costs ( 767 ) ( 662 ) Total capitalized cloud computing costs $ 1,610 $ 1,348 Thermal Barrier Contracts The Company is party to production contracts with General Motors to supply fabricated, multi-part thermal barriers (Barriers) for use in the battery system of its next-generation electric vehicles (Contracts). Pursuant to the Contracts, the Company is obligated to supply Barriers at fixed annual prices and at volumes to be specified by General Motors up to a daily maximum quantity through the respective terms of the agreements, which expire at various times from 2026 through 2034. While General Motors has agreed to purchase its requirement for Barriers from the Company for locations to be designated from time to time by General Motors, it has no obligation to purchase any minimum quantity of Barriers under the Contracts. In addition, General Motors may terminate the Contracts at any time and for any or no reason. All other terms of the Contracts are generally consistent with General Motors' standard purchase terms, including quality and warranty provisions customary in automotive industry. Charges for Engineering Change In January 2024, the Company was notified by a customer of an engineering change to one of the parts the Company manufactures for that customer to enable incremental productivity and support a set of broader system level changes that could drive higher demand for its parts. The Company has submitted a preliminary claim to the customer for reimbursement for estimated inventory and equipment losses incurred by the Company and its vendors due to potential obsolescence. The customer’s ordinary course process is to audit the claim to determine the proposed reimbursable amount. The Company expects the matter to be concluded by the second quarter of 2024. In connection with the same, the Company has recognized a charge of $ 6.8 million, net of contractual recoverable of $ 1.9 million, in cost of revenues for inventory obsolescence and impairment of equipment. Federal, State and Local Environmental Regulations The Company is subject to federal, state and local environmental laws and regulations. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation. Penalties may be imposed for noncompliance. Litigation The Company is, from time to time, a party to litigation that arises in the normal course of its business operations. See Part II, Item 1 “Legal Proceedings” of this Quarterly Report on Form 10-Q for a description of certain of the Company’s current legal proceedings. The Company is not presently a party to any litigation for which it believes a loss is probable requiring an amount to be accrued or a possible loss contingency requiring disclosure. Purchase Commitments As of March 31, 2024, the Company had purchase commitments of approximately $ 266.8 million, which included capital commitments of $ 202.7 million. Purchase commitments related to capital expenditures are anticipated to be spent over the next three years , while the Company's remaining purchase commitments are anticipated to be spent throughout 2024. Purchase obligations relate primarily to open purchase orders for capital expenditures, inventories, and goods and services. Purchase obligations are entered into with various vendors in the normal course of business and are consistent with the Company's expected requirements.

Leases and sale and leaseback

Leases and sale and leaseback	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases and sale and leaseback	(10) Leases and sale and leaseback The Company leases office, laboratory, warehouse and fabrication space in Massachusetts, Rhode Island and Monterrey, Mexico under operating leases. Under these agreements, the Company is obligated to pay annual rent, real estate taxes, and certain other operating expenses. The Company also leases equipment under operating leases. The Company’s operating leases expire at various dates through 2034 . The Company determines if an arrangement is a lease at inception. Right-of-use (ROU) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s payment obligations under the lease. Operating lease ROU assets and liabilities are recognized based on the present value of lease payments over the lease term. To measure its lease liabilities, the Company uses its incremental borrowing rate or the rate implicit in the lease, if available. The Company calculates its incremental borrowing rate using a synthetic credit rating analysis based on Moody’s Building Materials Industry Rating Methodology. ROU assets also include any direct costs and prepaid lease payments but exclude any lease incentives received. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company elected the short-term lease recognition exemption for all leases that qualify. For leases that qualify for this exemption, the Company does not recognize ROU assets or lease liabilities. For lease agreements with lease and non-lease components, the Company accounts for each component separately. However, in the case of equipment leases, the Company accounts for lease and non-lease components as a single component. Maturities of operating lease liabilities as of March 31, 2024 are as follows: Year Operating (In thousands) 2024 (excluding the three months ended March 31, 2024) $ 3,303 2025 4,424 2026 4,077 2027 3,793 2028 3,946 Thereafter 19,174 Total lease payments 38,717 Less imputed interest ( 15,328 ) Total lease liabilities $ 23,389 The Company incurred operating lease costs of $ 1.4 million and $ 1.1 million during the three months ended March 31, 2024 and 2023, respectively. Cash payments related to operating lease liabilities were $ 1.3 million and $ 1.0 million during the three months ended March 31, 2024 and 2023, respectively. As of March 31, 2024, the weighted average remaining lease term for operating leases was 8.8 years. As of March 31, 2024, the weighted average discount rate for operating leases was 12.0 % . As of March 31, 2024, the Company has additional operating real estate leases that will commence during 2024 with total lease payments of $ 3.2 million and a weighted average lease term of 5.0 years. Sale and leaseback transaction In January 2024, the Company entered into a sale and leaseback arrangement, pursuant to which the Company sold certain equipment to an equipment leasing company for a one-time cash payment of $ 5.0 million and leased back such equipment from the leasing company. The transaction was considered as a failed sale and leaseback transaction and accordingly, was accounted as a financing transaction. The Company did not recognize a gain on any of the proceeds received from the lessor that contractually constitute payments to acquire the assets subject to these arrangements. Instead, the sale proceeds received were accounted for as finance obligations. The outstanding finance obligation balance as of March 31, 2024 was $ 4.8 million. The monthly lease rents will be paid over the term of three years and will be allocated between interest expense and principal repayment of the financial liability.

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock based compensation	(11) Stock based compensation During the three months ended March 31, 2024, the Company granted 238,986 restricted common stock units (RSUs) with an aggregate grant date fair value of $ 3.9 million and non-qualified stock options (NSOs) to purchase 564,535 shares of common stock with an aggregate grant date fair value of $ 6.3 million to employees under its equity incentive plans . The RSUs and NSOs granted to employees will typically vest over a three-year period. Stock-based compensation is included in cost of revenue or operating expenses, as applicable, and consists of the following: Three Months Ended March 31, 2024 2023 (In thousands) Cost of product revenue $ 161 $ 134 Research and development expenses 424 30 Sales and marketing expenses 322 314 General and administrative expenses 3,799 1,789 Total stock-based compensation $ 4,706 $ 2,267 The 2023 Equity Plan was approved by stockholders at the Company’s annual meeting of stockholders on June 1, 2023 as the successor to the Company’s 2014 Employee, Director and Consultant Equity Incentive Plan (the 2014 Equity Plan), and no further awards may be made under the 2014 Equity Plan after that date. As of March 31, 2024, 5,533,077 shares of common stock were reserved for issuance upon the exercise or vesting of outstanding stock-based awards granted under the Company’s equity incentive plans. Any cancellations or forfeitures of awards outstanding under the 2023 Equity Plan, the 2014 Equity Plan or the 2001 Equity Incentive Plan, as amended (the 2001 Equity Plan) will result in the shares reserved for issuance pursuant to such awards becoming available for grant under the 2023 Equity Plan. As of March 31, 2024, the Company has either reserved in connection with statutory tax withholdings or issued a total of 5,491,916 shares under the Company’s equity incentive plans. As of March 31, 2024, there were 2,097,001 shares of common stock available for future grant under the 2023 Equity Plan. On March 5, 2024, the Compensation and Leadership Development Committee (the Committee) of the Board of Directors of the Company approved the cancellation of the outstanding, unearned portion of the performance-based restricted shares granted to certain employees pursuant to the 2014 Equity Plan on June 29, 2021 (to Donald R. Young) and June 2, 2022 (to certain other employees). The Committee determined that based on current market conditions, the likelihood of achievement of any of the remaining performance hurdles applicable to the unearned restricted shares is remote, and that the unearned restricted shares therefore had ceased to have incentive value for the grantees. On March 6, 2024, the Company entered into cancellation agreements, pursuant to which the applicable employees agreed to such cancellation. The cancelled unearned restricted shares were added to the number of shares available for awards under the Company’s 2023 Equity Incentive Plan. For financial accounting purposes, the cancellation of the unearned restricted shares resulted in the immediate charge of approximately $ 2.2 million of unamortized stock compensation costs of which $ 2.0 million is included in the general and administrative expenses and $ 0.2 million is included in research and development expenses in the accompanying consolidated statement of operations.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	(12) Net Loss Per Share The computation of basic and diluted net loss per share consists of the following: Three Months Ended March 31, 2024 2023 (In thousands, except Numerator: Net loss $ ( 1,835 ) $ ( 16,796 ) Denominator: Weighted average shares outstanding, basic and diluted 75,762,893 69,162,739 Net loss per share, basic and diluted $ ( 0.02 ) $ ( 0.24 ) Potentially dilutive common shares that were excluded from the computation of diluted net loss per share because they were anti-dilutive consist of the following: Three Months Ended March 31, 2024 2023 Common stock options 5,604,256 4,330,797 Restricted common stock units 604,220 458,262 Restricted common stock awards 201,878 857,933 Convertible note, if converted 4,045,687 3,687,070 Total 10,456,041 9,334,062 As the Company incurred a net loss for the three months ended March 31, 2024 and 2023 , the potential dilutive shares from common stock options, restricted common stock units, restricted common stock awards, and the convertible note were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive for the periods presented. The Company excludes the shares issued in connection with restricted stock awards from the calculation of basic weighted average common shares outstanding until the restrictions lapse.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	(13) Income Taxes The Company incurred net operating losses and recorded a full valuation allowance against net deferred tax assets for all periods presented. Accordingly, the Company has not recorded a provision for federal or state income taxes. The Company has provided $ 0.8 million of income tax expense related to its Mexican maquiladora operations for the quarter ended March 31, 2024 .

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Information	(14) Segment Information Operating segments are identified as components of an enterprise about which separate, discrete financial information is available for evaluation by the chief operating decision maker in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the Chief Executive Officer. The Company’s chief operating decision maker reviews consolidated operating results to make decisions about allocating resources and assessing performance for the entire Company. The Company reports two segments: Energy Industrial and Thermal Barrier. We evaluate segment performance based on the segment profit (loss) before corporate expenses. Summarized below are the Revenue and Segment Operating Profit for each reporting segment: Revenue Segment Operating Profit (Loss) Three Months Ended Three Months Ended March 31, March 31, 2024 2023 2024 2023 (In thousands) Energy industrial $ 29,082 $ 33,875 $ 11,562 $ 8,881 Thermal barrier 65,419 11,711 23,581 ( 3,795 ) Total $ 94,501 $ 45,586 $ 35,143 $ 5,086 Corporate expenses 32,707 23,994 Operating gain (loss) 2,436 ( 18,908 ) Other (expense) income, net ( 3,515 ) 2,112 Income tax expense ( 756 ) - Net loss $ ( 1,835 ) $ ( 16,796 ) Total Assets March 31, December 31, 2024 2023 (In thousands) Energy industrial $ 103,304 $ 93,168 Thermal barrier 127,199 118,565 Total assets of reportable segments 230,503 211,733 Construction in progress 322,012 314,678 All other corporate assets 145,474 176,637 $ 697,989 $ 703,048

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	(15) Subsequent Events The Company has evaluated subsequent events through May 2, 2024, the date of issuance of the consolidated financial statements for the three months ended March 31, 2024 .

Description of Business and B_2

Description of Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Nature of Business	Nature of Business Aspen Aerogels, Inc. (the Company) is an aerogel technology company that designs, develops and manufactures innovative, high-performance aerogel insulation used primarily in the energy industrial and sustainable insulation materials markets. In addition, the Company has introduced a line of aerogel thermal barriers for use in battery packs in the electric vehicle market. The Company is also developing applications for its aerogel technology in the battery materials and a number of other high-potential markets. The Company maintains its corporate offices in Northborough, Massachusetts. The Company has three wholly owned subsidiaries: Aspen Aerogels Rhode Island, LLC, Aspen Aerogels Germany, GmbH and Aspen Aerogels Georgia, LLC. Additionally, we engaged Prodensa Servicios de Consultora to establish OPE Manufacturer Mexico S de RL de CV, a maquiladora located in Mexico, (“OPE”) which manufactures thermal barrier PyroThin products and operates an automated fabrication facility for PyroThin. OPE is currently owned by Prodensa, which charges a management fee. There is an option for OPE to be purchased by the Company after a period of 18 months. During the period between inception and the exercise of the purchase option, OPE operations are consolidated within the Company financial statements.
Liquidity	Liquidity During the three months ended March 31, 2024, the Company incurred a net loss of $ 1.8 million, used $ 17.7 million of cash in operations and used $ 25.9 million of cash for capital expenditures. The Company had unrestricted cash and cash equivalents of $ 101.5 million as of March 31, 2024. In November 2022, the Company entered into a loan agreement (the GM Loan Agreement) with General Motors Holdings LLC (GM), an entity affiliated with General Motors LLC, which provides for a multi-draw senior secured term loan (the GM Loan) in an aggregate principal amount of up to $ 100.0 million, available to the Company on a delayed draw basis beginning January 1, 2023 to September 30, 2023 , subject to certain conditions precedent to funding. In September 2023, the Company amended the GM Loan Agreement to (i) extend the draw period for the GM Loan to a period beginning on the date that is twelve months prior to the date agreed upon by the Company and GM for the start of production at an aerogel manufacturing facility in Bulloch County, Georgia (the Plant) and ending on March 31, 2024 (or any later date approved in writing by GM at its sole discretion); (ii) extend the maturity date of the GM Loan from March 31, 2025 to September 30, 2025; and (iii) add financial covenants measured starting from the fiscal quarter ending December 31, 2024 and at the end of each fiscal quarter thereafter. As of March 31, 2024, the Company has not drawn, and no longer has the ability to draw on the GM Loan. The associated unamortized deferred financing costs of $ 1.7 million were written off to interest expense upon the expiration of the draw period. In January 2024 , the Company entered i nto a sale and leaseback arrangement, pursuant to which the Company sold certain equipment to an equipment leasing company for a one-time cash payment of $ 5.0 million and leased back such equipment from the leasing company. The associated monthly lease rents will be paid over the lease term of three years . The Company is increasing investment in the research and development of next-generation aerogel products and manufacturing process technologies. In addition, the Company has developed a number of promising aerogel products and technologies for the electric vehicle market. The Company believes that the commercial potential for the Company’s products and technology in the electric vehicle market is significant. Accordingly, the Company is hiring additional personnel, incurring additional operating expenses, incurring significant capital expenditures to expand aerogel manufacturing capacity and automated thermal barrier fabrication operations, and enhancing research and development resources, among other items. The Company expects its existing cash balance will be sufficient to support current operating requirements, current research and development activities and the initial capital expenditures required to support the evolving commercial opportunity in the electric vehicle market and other strategic business initiatives. However, the Company plans to supplement its cash balance with equity financings, debt financings, equipment leasing, sale and leaseback transactions, c ustomer prepayments, or government grant and loan programs to provide the additional capital necessary to purchase the capital equipment, construct the new facilities, establish the operations and complete the aerogel capacity expansions required to support these evolving commercial opportunities and strategic business initiatives.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying unaudited interim consolidated financial statements include the accounts of the Company and have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and disclosures normally included in the consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements and accompanying notes in our Annual Report on Form 10-K for the year ended December 31, 2023 (the Annual Report), filed with the U.S. Securities and Exchange Commission on March 7, 2024. In the opinion of the Company’s management, the unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments that are of a normal recurring nature and necessary for the fair statement of the Company’s financial position as of March 31, 2024 and the results of its operations and stockholders’ equity for the three months ended March 31, 2024 and 2023 and the cash flows for the three-month periods then ended. The Company has evaluated subsequent events through the date of this filing. The Company’s results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or any other period.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements requires the Company to make a number of estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include allowances for doubtful accounts, sales returns and allowances, product warranty costs, inventory valuation, the carrying amount of property and equipment, right-of-use assets, lease liabilities, stock-based compensation, and deferred income taxes. The Company evaluates its estimates and assumptions on an on-going basis using historical experience and other factors, including current economic conditions, which are believed to be reasonable under the circumstances. Management adjusts such estimates and assumptions when facts and circumstances warrant. Illiquid credit markets, volatile equity markets and declines in business investment can increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.
Restricted Cash	Restricted Cash As of March 31, 2024, the Company had $ 0.2 million of restricted cash to support its outstanding letters of credit.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments, which potentially expose the Company to concentrations of credit risk, consist principally of accounts receivable. The Company’s customers are primarily insulation distributors, insulation contractors, insulation fabricators and select energy and automotive end-users located throughout the world. The Company performs ongoing credit evaluations of its customers’ financial condition and generally requires no collateral to secure accounts receivable. The Company maintains an allowance for doubtful accounts based on its assessment of the collectability of accounts receivable. The Company reviews the allowance for doubtful accounts quarterly. During both the three months ended March 31, 2024 and 2023, the Company recorded an increase for estimated customer uncollectible accounts receivable of less than $ 0.1 million. For the three months ended March 31, 2024 and 2023 , two customers represented 64 % and 45 % of total revenue, respectively. At March 31, 2024 , the Company had one customer which accounted for 64 % of accounts receivable. At December 31, 2023, the Company had two customers which accounted for 60 % and 6 % of accounts receivable, respectively.
Revenue Recognition	Revenue Recognition The Company recognizes revenue in accordance with Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606). See note 3 for further details.
Warranty	Warranty The Company provides warranties for its products and records the estimated cost within cost of revenue in the period that the related revenue is recorded. The Company’s standard warranty period for energy industrial products extends to one year from the date of shipment. This standard warranty provides that the Company’s products will be free from defects in material and workmanship, and will, under normal use, conform to the specifications for the product. The Company’s thermal barrier products provide quality and warranty provisions customary in the automotive industry. The Company recorded warranty expense related to its thermal barrier products of $ 0.2 million during the three months ended March 31, 2024 and less than $ 0.1 million during the three months ended March 31, 2023 .
Sale and Leaseback Accounting	Sale and Leaseback Accounting The Company has entered into sale and leaseback transactions for certain equipment within its plants. Due to the Company not meeting criteria to account for the transfer of the assets as a sale, sale accounting is precluded. Accordingly, the Company uses the financing method to account for these transactions. Under the financing method of accounting for a sale and leaseback, the Company does not derecognize the assets and does not recognize as revenue any of the sale proceeds received from the lessor that contractually constitutes payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as finance obligations and leaseback payments made by the Company are allocated between interest expense and a reduction to the finance obligation. Interest on the finance obligation is calculated using the Company’s incremental borrowing rate at the inception of the arrangement on the outstanding finance obligation.
Recently Issued Accounting Standards	Recently Issued Accounting Standards From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies. Recently issued standards typically do not require adoption until a future effective date. Prior to their effective date, the Company evaluates the pronouncements to determine the potential effects of adoption to its consolidated financial statements. Standards Implemented Since December 31, 2023 The Company has not implemented any accounting standards that had a material impact on its consolidated financial statements during the three months ended March 31, 2024. Standards to be Implemented In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2023-07 Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures to enhance disclosures about significant segment expenses. This ASU is effective for the Company’s fiscal year 2024 and interim periods in fiscal year 2025. Early adoption is permitted. The Company is currently evaluating segment expense disclosures related to its annual report for fiscal year 2024. In December 2023, the FASB issued ASU 2023-09 Income Taxes (Topic 740) Improvements to Income Tax Disclosures that requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. This ASU is effective for the Company’s fiscal year 2025. Early adoption is permitted. The Company is currently evaluating income tax disclosures related to its annual report for fiscal year 2025. Although there are several other new accounting pronouncements issued by the FASB, the Company does not believe any of these accounting pronouncements had or will have a material impact on its Consolidated Financial Statements. The Company believes that the impact of recently issued accounting standards that are not yet effective will not have a material impact on its consolidated financial statements.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Summary of Revenue Disaggregated by Geographical Region and Source of Revenue	In the following tables, revenue is disaggregated by primary geographical region and source of revenue: Three Months Ended March 31, 2024 2023 U.S. International Total U.S. International Total (In thousands) Geographical region Asia $ — $ 7,213 $ 7,213 $ — $ 11,784 $ 11,784 Canada — 1,868 1,868 — 324 324 Europe — 9,361 9,361 — 5,412 5,412 Latin America — 15,371 15,371 — 1,624 1,624 U.S. 60,688 — 60,688 26,442 — 26,442 Total revenue $ 60,688 $ 33,813 $ 94,501 $ 26,442 $ 19,144 $ 45,586 Source of revenue Energy industrial $ 14,033 $ 15,049 $ 29,082 $ 16,504 $ 17,371 $ 33,875 Thermal barrier 46,655 18,764 65,419 9,938 1,773 11,711 Total revenue $ 60,688 $ 33,813 $ 94,501 $ 26,442 $ 19,144 $ 45,586
Summary of Changes in Contract Assets and Contract Liabilities	The following table presents changes in the Company’s contract liabilities during the three months ended March 31, 2024: Balance at Additions Deductions Balance at (In thousands) Contract liabilities Deferred revenue Energy industrial $ 2,316 $ 2,941 $ ( 2,127 ) $ 3,130 Total contract liabilities $ 2,316 $ 2,941 $ ( 2,127 ) $ 3,130

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consist of the following: March 31, December 31, 2024 2023 (In thousands) Raw materials $ 19,190 $ 24,735 Work in process 13,936 7,936 Finished goods 12,624 6,518 Total $ 45,750 $ 39,189

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Property, plant and equipment consist of the following: March 31, December 31, Useful 2024 2023 life (In thousands) Construction in progress $ 322,030 $ 314,695 — Buildings 25,985 25,473 30 years Machinery and equipment 187,075 185,339 3 - 10 years Computer equipment and software 9,631 9,495 3 years Leasehold improvements 23,472 23,514 Shorter of useful life or lease term Total 568,193 558,516 Accumulated depreciation ( 145,457 ) ( 141,289 ) Property, plant and equipment, net $ 422,736 $ 417,227

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following: March 31, December 31, 2024 2023 (In thousands) Employee compensation $ 5,710 $ 16,876 Other accrued expenses 7,052 5,935 Total $ 12,762 $ 22,811

Convertible Note - Related Pa_2

Convertible Note - Related Party (Tables)	3 Months Ended
	Mar. 31, 2024
Convertible Notes [Abstract]
Summary of Convertible Notes	In accordance with ASU 2020-06, the 2022 Convertible Note is accounted for as a single unit of account and consists of the following: March 31, December 31, 2024 2023 (In thousands) Convertible note, principal $ 100,000 $ 100,000 Payment in-kind 18,318 18,318 Accrued interest 2,810 - Discount on convertible note, net of accumulated amortization ( 2,990 ) ( 3,209 ) Debt issuance costs, net of accumulated amortization ( 108 ) ( 117 ) Convertible note $ 118,030 $ 114,992 The 2022 Convertible Note does not have current observable inputs such as recent trading prices (Level 1) and is measured at fair value using a combination of option pricing and discounted cash flow models and incorporate management’s assumptions for stock price, volatility and risk rate. In general, fair values determined by Level 1 inputs utilize observable inputs such as quoted prices in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are either directly or indirectly observable, such as quoted prices for similar instruments in active markets, interest rates and yield curves. Fair values determined by Level 3 inputs utilize unobservable data points in which there is little or no market data, which require the Company to develop its own assumptions for the asset or liability. The Company estimated the fair value of the 2022 Convertible Notes is approximately $ 118.7 million as of March 31, 2024. However, as the Company has not elected to utilize the fair value option, it is carried at amortized cost of $ 118.0 million.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Summary of Capitalized Implementation Costs are Classified on the Consolidated Balance Sheets	The capitalized implementation costs are classified on the consolidated balance sheets as follows: March 31, December 31, 2024 2023 (In thousands) Cloud computing costs included in other current assets $ 420 $ 420 Cloud computing costs included in other assets 1,957 1,590 Amortization of cloud computing costs ( 767 ) ( 662 ) Total capitalized cloud computing costs $ 1,610 $ 1,348

Leases and sale and leaseback (

Leases and sale and leaseback (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Summary of Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities as of March 31, 2024 are as follows: Year Operating (In thousands) 2024 (excluding the three months ended March 31, 2024) $ 3,303 2025 4,424 2026 4,077 2027 3,793 2028 3,946 Thereafter 19,174 Total lease payments 38,717 Less imputed interest ( 15,328 ) Total lease liabilities $ 23,389

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock Based Compensation Included in Cost of Revenue or Operating Expenses	Stock-based compensation is included in cost of revenue or operating expenses, as applicable, and consists of the following: Three Months Ended March 31, 2024 2023 (In thousands) Cost of product revenue $ 161 $ 134 Research and development expenses 424 30 Sales and marketing expenses 322 314 General and administrative expenses 3,799 1,789 Total stock-based compensation $ 4,706 $ 2,267

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss Per Share	The computation of basic and diluted net loss per share consists of the following: Three Months Ended March 31, 2024 2023 (In thousands, except Numerator: Net loss $ ( 1,835 ) $ ( 16,796 ) Denominator: Weighted average shares outstanding, basic and diluted 75,762,893 69,162,739 Net loss per share, basic and diluted $ ( 0.02 ) $ ( 0.24 )
Summary of Potentially Dilutive Common Shares Excluded from Computation of Diluted Net Loss Per Share	Potentially dilutive common shares that were excluded from the computation of diluted net loss per share because they were anti-dilutive consist of the following: Three Months Ended March 31, 2024 2023 Common stock options 5,604,256 4,330,797 Restricted common stock units 604,220 458,262 Restricted common stock awards 201,878 857,933 Convertible note, if converted 4,045,687 3,687,070 Total 10,456,041 9,334,062

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Summary of Revenue and Segment Operating Profit	Summarized below are the Revenue and Segment Operating Profit for each reporting segment: Revenue Segment Operating Profit (Loss) Three Months Ended Three Months Ended March 31, March 31, 2024 2023 2024 2023 (In thousands) Energy industrial $ 29,082 $ 33,875 $ 11,562 $ 8,881 Thermal barrier 65,419 11,711 23,581 ( 3,795 ) Total $ 94,501 $ 45,586 $ 35,143 $ 5,086 Corporate expenses 32,707 23,994 Operating gain (loss) 2,436 ( 18,908 ) Other (expense) income, net ( 3,515 ) 2,112 Income tax expense ( 756 ) - Net loss $ ( 1,835 ) $ ( 16,796 ) Total Assets March 31, December 31, 2024 2023 (In thousands) Energy industrial $ 103,304 $ 93,168 Thermal barrier 127,199 118,565 Total assets of reportable segments 230,503 211,733 Construction in progress 322,012 314,678 All other corporate assets 145,474 176,637 $ 697,989 $ 703,048

Description of Business and B_3

Description of Business and Basis of Presentation - Additional Information (Detail) $ in Thousands	1 Months Ended		3 Months Ended
	Jan. 31, 2024 USD ($)	Nov. 30, 2022 USD ($)	Mar. 31, 2024 USD ($) Subsidiary	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Basis Of Presentation [Line Items]
Number of Subsidiaries | Subsidiary			3
Period of option to purchase			18 months
Net loss incurred			$ 1,835	$ 16,796
Cash used in operations			17,749	$ 24,651
Cash for capital expenditures			25,900
Deferred financing costs written off			1,709
Sale and leaseback arrangement date	January 2024
Sale and leaseback equipment value	$ 5,000
Sale and leaseback rent payment term	3 years
Unrestricted cash and cash equivalents			101,461		$ 139,723
General Motors Holdings LLC [Member] | Loan Agreement [Member]
Basis Of Presentation [Line Items]
Aggregate principal amount		$ 100,000
Senior secured term loan, Draw beginning date		Jan. 01, 2023
Senior secured term loan, Draw Endining date		Sep. 30, 2023
Deferred financing costs written off			$ 1,700

Significant Accounting Polici_2

Significant Accounting Policies - Additional Information (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($) Customer shares	Mar. 31, 2023 USD ($) Customer	Dec. 31, 2023 USD ($) Customer shares
Summary Of Significant Accounting Policies [Line Items]
Reduction/Charge for uncollectible accounts receivable		$ 99
Period of option to purchase	18 months
Restricted cash to support our outstanding letters of credit	$ 157		$ 248
Restricted common stock issued | shares	76,077,929		76,503,151
Energy Industrial [Member]
Summary Of Significant Accounting Policies [Line Items]
Standard product warranty period	1 year
Thermal Barrier [Member]
Summary Of Significant Accounting Policies [Line Items]
Warranty expense	$ 200
Equity Incentive Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Shares reserved for issuance | shares	5,533,077
Number of shares either issued or reserved in connection with statutory tax withholdings | shares	5,491,916
Equity Incentive Plan [Member] | Non-Qualified Stock Options [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock-based awards granted to purchase common stock | shares	564,535
Stock-based awards granted to purchase common stock, grant date fair value	$ 6,300
Stock-based award vesting period	3 years
Equity Incentive Plan [Member] | Restricted Stock Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock-based awards granted to purchase common stock | shares	238,986
Stock-based awards granted to purchase common stock, grant date fair value	$ 3,900
Stock-based award vesting period	3 years
2023 Equity Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Increased number of shares available for grant | shares	2,097,001
Revenue [Member] | Customer Concentration Risk [Memeber] | Two Customers [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	2	2
Revenue [Member] | Customer Concentration Risk [Memeber] | Customer A [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	64%	64%
Revenue [Member] | Customer Concentration Risk [Memeber] | Customer B [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	45%	45%
Accounts Receivable [Member] | Customer Concentration Risk [Memeber] | Two Customers [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer			2
Accounts Receivable [Member] | Customer Concentration Risk [Memeber] | One Customer [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	64%
Number of customers | Customer	1
Accounts Receivable [Member] | Customer Concentration Risk [Memeber] | Customer A [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage			60%
Accounts Receivable [Member] | Customer Concentration Risk [Memeber] | Customer B [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage			6%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Reduction/Charge for uncollectible accounts receivable	$ 100	$ 100
Maximum [Member] | Thermal Barrier [Member]
Summary Of Significant Accounting Policies [Line Items]
Warranty expense		$ 100

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) Agreement	Dec. 31, 2023 USD ($)
Revenue Recognition [Line Items]
Deferred revenue, revenue recognized	$ 1.2
Maximum [Member]
Revenue Recognition [Line Items]
Sales return reserves	$ 0.2	$ 0.2
Energy Industrial [Member]
Revenue Recognition [Line Items]
Number of performance obligations | Agreement	1

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Summary of Revenue Disaggregated by Geographical Region and Source of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Total revenue	$ 94,501	$ 45,586
Energy Industrial [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	29,082	33,875
Thermal Barrier [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	65,419	11,711
Asia [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	7,213	11,784
Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,868	324
Europe [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	9,361	5,412
Latin America [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	15,371	1,624
U.S. [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	60,688	26,442
U.S. [Member] | Energy Industrial [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	14,033	16,504
U.S. [Member] | Thermal Barrier [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	46,655	9,938
International [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	33,813	19,144
International [Member] | Energy Industrial [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	15,049	17,371
International [Member] | Thermal Barrier [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 18,764	$ 1,773

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Summary of Changes in Contract Assets and Contract Liabilities (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Contract liabilities
Beginning Balance	$ 2,316
Additions	2,941
Deductions	(2,127)
Ending Balance	3,130
Energy Industrial [Member]
Contract liabilities
Beginning Balance	2,316
Additions	2,941
Deductions	(2,127)
Ending Balance	$ 3,130

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials	$ 19,190	$ 24,735
Work in process	13,936	7,936
Finished goods	12,624	6,518
Total	$ 45,750	$ 39,189

Property, Plant and Equipment_3

Property, Plant and Equipment, Net - Summary of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 568,193	$ 558,516
Accumulated depreciation	(145,457)	(141,289)
Property, plant and equipment, net	422,736	417,227
Construction in Progress [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, gross	322,030	314,695
Buildings [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 25,985	25,473
Property, plant and equipment, Useful life	30 years
Machinery and Equipment [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 187,075	185,339
Machinery and Equipment [Member] | Minimum [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, Useful life	3 years
Machinery and Equipment [Member] | Maximum [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, Useful life	10 years
Computer Equipment and Software [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 9,631	9,495
Property, plant and equipment, Useful life	3 years
Leasehold Improvements [Member]
Property Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 23,472	$ 23,514
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember

Property, Plant and Equipment_4

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Property Plant and Equipment [Line Items]
Depreciation	$ 5,786,000	$ 2,704,000
Impairment charges of property, plant and equipment	6,039,000	0
Capitalized interest		2,561,000
Georgia [Member]
Property Plant and Equipment [Line Items]
Pre-construction costs	296,700,000		$ 288,500,000
Capitalized interest	0	$ 2,600,000
Georgia [Member] | Construction in Progress [Member]
Property Plant and Equipment [Line Items]
Capitalized interest	$ 8,800,000

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Employee compensation	$ 5,710	$ 16,876
Other accrued expenses	7,052	5,935
Total	$ 12,762	$ 22,811

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	Nov. 28, 2022 $ / shares	Nov. 27, 2022 $ / shares	Mar. 31, 2024 USD ($) $ / shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Related Party Transaction [Line Items]
Accrued interest | $			$ 2,810
Accounts Payable | $			44,713	$ 51,094
Koch Disruptive Technologies LLC [Member]
Related Party Transaction [Line Items]
Accounts Payable | $			1,200	$ 2,800
2022 Convertible Notes [Member]
Related Party Transaction [Line Items]
Accrued interest | $			$ 2,800
Conversion notes effective conversion price per share | $ / shares			$ 29.936625
Common stock per capitalized principal | $ / shares			$ 1,000
Initial conversion rate of convertible notes			33.4001
2022 Convertible Notes [Member] | Wood River Capital, LLC [Member]
Related Party Transaction [Line Items]
Issuance and sale of convertible notes | $					$ 100,000
Conversion notes effective conversion price per share decrease | $ / shares	$ 5
Conversion notes effective conversion price per share | $ / shares	29.936625	$ 34.936625
Common stock per capitalized principal | $ / shares	$ 1,000	$ 1,000
Initial conversion rate of convertible notes	33.4001	28.623257

Convertible Note - Related Pa_3

Convertible Note - Related Party - Additional Information (Detail) $ / shares in Units, $ in Thousands				3 Months Ended
	Nov. 28, 2022 $ / shares	Nov. 27, 2022 $ / shares	Feb. 15, 2022 USD ($)	Mar. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($)	Dec. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Dec. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)
Convertible Notes [Line Items]
Issuance and sale of convertible notes				$ 100,000	$ 100,000
Payment in-kind						$ 5,400	$ 5,100	$ 4,900	$ 2,900
Accrued interest				$ 2,810
Debt instrument, interest rate terms				Interest on the 2022 Convertible Note is payable semi-annually in arrears on June 30 and December 30. The Company, at its option, is permitted to settle each semi-annual interest payment in cash, in-kind, or any combination thereof.
Debt issuance costs, net of accumulated amortization				$ 108	$ 117
Amortized Debt Discount Premium				$ 1,100
Purchase price of notes percentage				100%
SOFR Plus [Member]
Convertible Notes [Line Items]
Debt instrument, interest rate				5.50%
SOFR Plus [Member] | Floor Rate [Member]
Convertible Notes [Line Items]
Debt instrument, interest rate				1%
SOFR Plus [Member] | Cap Rate [Member]
Convertible Notes [Line Items]
Debt instrument, interest rate				3%
SOFR Plus [Member] | PIK Interest [Member]
Convertible Notes [Line Items]
Debt instrument, interest rate				6.50%
2022 Convertible Notes [Member]
Convertible Notes [Line Items]
Convertible notes, fair value				$ 118,700
Convertible debt carried at amortized cost				118,000
Accrued interest				2,800
Debt Instrument Unamortized Discount				$ 4,100
Debt Instrument Effective Interest Rate				10.70%
Initial conversion rate of convertible notes				33.4001
Common stock per capitalized principal | $ / shares				$ 1,000
Conversion notes effective conversion price per share | $ / shares				$ 29.936625
Common stock issuable upon conversion of convertible notes | shares				4,045,687
Percentage of common stock closing price per share of conversion price				130%
Number of trading days on conversion price				20 consecutive trading days
Convertible notes redemption terms				The 2022 Convertible Note is redeemable at the Company’s option at any time and in the event that the volume weighted average price of the Company’s common stock for the 10 trading days immediately preceding the date on which the Company provides the redemption notice has been at least 130% of the Conversion Price then in effect at a redemption price of 100% of the principal amount, plus accrued and unpaid interest (excluding the redemption date), plus the Make-Whole Amount.
Convertible notes redemption percentage				130%
Redemption price, percentage of principal amount redeemed				100%
2022 Convertible Notes [Member] | Wood River Capital, LLC [Member]
Convertible Notes [Line Items]
Initial conversion rate of convertible notes	33.4001	28.623257
Common stock per capitalized principal | $ / shares	$ 1,000	$ 1,000
Conversion notes effective conversion price per share | $ / shares	29.936625	$ 34.936625
Conversion notes effective conversion price per share decrease | $ / shares	$ 5
2022 Convertible Notes [Member] | Koch Strategic Platforms (KSP) [Member]
Convertible Notes [Line Items]
Issuance and sale of convertible notes			$ 100,000
Debt instrument, issuance date			Feb. 15, 2022
Existing maturity date			Feb. 18, 2027	Feb. 18, 2027

Convertible Note - Related Pa_4

Convertible Note - Related Party - Summary of Convertible Notes (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Convertible Notes [Abstract]
Convertible note, principal	$ 100,000	$ 100,000
Payment in-kind	18,318	18,318
Accrued interest	2,810
Discount on convertible note, net of accumulated amortization	(2,990)	(3,209)
Debt issuance costs, net of accumulated amortization	(108)	(117)
Convertible note	$ 118,030	$ 114,992

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Commitments And Contingencies [Line Items]
Charge recognized in cost of revenues for inventory obsolescence and impairment of equipment	$ 6.8
Contractual recoverable, net	1.9
Purchase commitments	266.8
Capital commitments	$ 202.7
Purchase commitments spent over period	3 years
Cloud Computing Agreement [Member] | Enterprise Resource Planning Software [Member]
Commitments And Contingencies [Line Items]
Adjusted amortization period	3 years
Thermal Barrier Contracts [Member] | General Motors
Commitments And Contingencies [Line Items]
Purchase commitment, description	While General Motors has agreed to purchase its requirement for Barriers from the Company for locations to be designated from time to time by General Motors, it has no obligation to purchase any minimum quantity of Barriers under the Contracts.

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Capitalized Implementation Costs are Classified on the Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Cloud computing costs included in other current assets	$ 420	$ 420
Cloud computing costs included in other assets	1,957	1,590
Amortization of cloud computing costs	(767)	(662)
Total capitalized cloud computing costs	$ 1,610	$ 1,348

Leases and sale and leaseback -

Leases and sale and leaseback - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2024	Mar. 31, 2024	Mar. 31, 2023
Lessee Lease Description [Line Items]
Operating lease expiry year		2034
Operating lease cost		$ 1.4	$ 1.1
Cash payments related to operating lease liabilities		$ 1.3	$ 1
Operating lease, weighted average remaining lease term		8 years 9 months 18 days
Operating lease, weighted average discount rate, percent		12%
Operating real estate lease liability payments not yet commenced		$ 3.2
Operating real estate lease liability payments not yet commenced, term		5 years
Sale and leaseback transaction one-time cash payment	$ 5
Outstanding finance obligation		$ 4.8
Sale and leaseback rent payment term	3 years

Leases and sale and leaseback_2

Leases and sale and leaseback - Summary of Maturities of Operating Lease Liabilities (Detail) $ in Thousands	Sep. 30, 2023 USD ($)
Leases [Abstract]
2024 (excluding the three months ended March 31, 2024)	$ 3,303
2025	4,424
2026	4,077
2027	3,793
2028	3,946
Thereafter	19,174
Total lease payments	38,717
Less imputed interest	(15,328)
Total lease liabilities	$ 23,389

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unamortized stock compensation costs | $	$ 2.2
Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for issuance | shares	5,533,077
Number of shares either issued or reserved in connection with statutory tax withholdings | shares	5,491,916
Equity Incentive Plan [Member] | Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based awards granted to purchase common stock | shares	238,986
Stock-based awards granted to purchase common stock, grant date fair value | $	$ 3.9
Stock-based award vesting period	3 years
Equity Incentive Plan [Member] | Non-Qualified Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based awards granted to purchase common stock | shares	564,535
Stock-based awards granted to purchase common stock, grant date fair value | $	$ 6.3
Stock-based award vesting period	3 years
2023 Equity Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Increased number of shares available for grant | shares	2,097,001
General and Administrative Expenses [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unamortized stock compensation costs | $	$ 2
Research and Development Expenses [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unamortized stock compensation costs | $	$ 0.2

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Stock Based Compensation Included in Cost of Revenue or Operating Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 4,706	$ 2,267
Cost of Product Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	161	134
Research and Development Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	424	30
Sales and Marketing Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	322	314
General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 3,799	$ 1,789

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net loss	$ (1,835)	$ (16,796)
Denominator:
Weighted average shares outstanding, basic	75,762,893	69,162,739
Weighted average shares outstanding, diluted	75,762,893	69,162,739
Net loss per share, basic	$ (0.02)	$ (0.24)
Net loss per share, diluted	$ (0.02)	$ (0.24)

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Potentially Dilutive Common Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	10,456,041	9,334,062
Common Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	5,604,256	4,330,797
Restricted Common Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	604,220	458,262
Restricted Common Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	201,878	857,933
Convertible Note If Converted [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Securities	4,045,687	3,687,070

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Income Taxes [Line Items]
Income tax expense	$ 756
Mexican Maquiladora Operations [Member]
Income Taxes [Line Items]
Income tax expense	$ 800

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2024 Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Segment Information - Summary o

Segment Information - Summary of Revenue and Segment Operating Profit (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenue	$ 94,501	$ 45,586
Segment Operating Profit (Loss)	35,143	5,086
Corporate expenses	32,707	23,994
Operating gain (loss)	2,436	(18,908)
Other (expense) income, net	(3,515)	2,112
Income tax expense	(756)
Net loss	(1,835)	(16,796)
Total assets	697,989		$ 703,048
Construction in Progress [Member]
Segment Reporting Information [Line Items]
Total assets	322,012		314,678
All Other Corporate Assets [Member]
Segment Reporting Information [Line Items]
Total assets	145,474		176,637
Operating Segment
Segment Reporting Information [Line Items]
Total assets	230,503		211,733
Operating Segment | Energy Industrial [Member]
Segment Reporting Information [Line Items]
Revenue	29,082	33,875
Segment Operating Profit (Loss)	11,562	8,881
Total assets	103,304		93,168
Operating Segment | Thermal Barrier [Member]
Segment Reporting Information [Line Items]
Revenue	65,419	11,711
Segment Operating Profit (Loss)	23,581	$ (3,795)
Total assets	$ 127,199		$ 118,565