OKLO INC., 10-Q filed on 8/7/2026
Quarterly Report
v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Aug. 04, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Transition Report false  
Entity File Number 001-40583  
Registrant Name Oklo Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 86-2292473  
Entity Address, Address Line One 3190 Coronado Dr.  
Entity Address, City or Town Santa Clara  
Entity Address, State or Province CA  
City Area Code 650  
Local Phone Number 550-0127  
Entity Address, Postal Zip Code 95054  
Title of 12(b) Security Class A common stock, par value $0.0001 per share  
Trading Symbol OKLO  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   186,017,650
Document Fiscal Year Focus 2026  
CIK 0001849056  
Amendment Flag false  
Document Fiscal Period Focus Q2  
Current Fiscal Year End Date --12-31  
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Current assets:    
Cash and cash equivalents $ 1,644,704 $ 788,445
Restricted cash 8,400 0
Marketable debt securities 820,454 439,526
Accounts receivable, net 1,979 0
Prepaid expenses and other current assets 45,372 25,798
Total current assets 2,520,909 1,253,769
Restricted cash, noncurrent portion 8,500 0
Marketable debt securities, net of current portion 541,131 184,568
Property, plant and equipment, net 176,195 42,312
Operating lease right-of-use assets 3,160 1,384
Intangible assets, net 44,203 27,500
Goodwill 16,535 6,621
Other assets 47,249 12,303
Total assets 3,357,882 1,528,457
Current liabilities:    
Accounts payable 10,470 4,145
Accrued expenses and other 38,023 20,497
Operating lease liabilities 1,025 904
Other current liabilities 2,499 0
Total current liabilities 52,017 25,546
Operating lease liabilities, net of current portion 2,234 546
Long-term debt, net of current portion 700 0
Right of first refusal liability 25,000 25,000
Deferred tax liabilities 1,157 1,155
Other liabilities 3,217 0
Total liabilities 84,325 52,247
Commitments and contingencies
Stockholders' equity:    
Class A common stock, $0.0001 par value – 500,000,000 shares authorized; 185,090,155 and 160,514,103 shares issued and outstanding as of June 30, 2026 and December 31, 2025, respectively 18 16
Additional paid-in capital 3,599,945 1,715,787
Accumulated deficit (322,373) (240,772)
Accumulated other comprehensive (loss) income (4,033) 1,179
Total stockholders’ equity 3,273,557 1,476,210
Total liabilities and stockholders’ equity $ 3,357,882 $ 1,528,457
v3.26.1
Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares
Jun. 30, 2026
Dec. 31, 2025
Statement of Financial Position [Abstract]    
Common stock, par value (in dollars per share) $ 0.0001 $ 0.0001
Common stock, authorized (in shares) 500,000,000 500,000,000
Common stock, issued (in shares) 185,090,155 160,514,103
Common stock, outstanding (in shares) 185,090,155 160,514,103
v3.26.1
Condensed Consolidated Statements of Operations (Unaudited) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Income Statement [Abstract]        
Revenue $ 1,210 $ 0 $ 1,210 $ 0
Operating expenses        
Cost of sales 721 0 721 0
Research and development 39,474 11,468 66,523 19,314
General and administrative 34,205 16,547 58,132 26,575
Total operating expenses 74,400 28,015 125,376 45,889
Loss from operations (73,190) (28,015) (124,166) (45,889)
Other income (expense)        
Interest and dividend income, net 23,209 3,761 44,548 7,414
Other non-operating expenses (1,708) 0 (1,981) 0
Total other income (expense) 21,501 3,761 42,567 7,414
Loss before income taxes (51,689) (24,254) (81,599) (38,475)
Income tax benefit (expense) 3,153 (431) (2) 3,980
Net loss $ (48,536) $ (24,685) $ (81,601) $ (34,495)
Net loss per share:        
Basic - Class A common stock (in dollars per share) $ (0.28) $ (0.18) $ (0.47) $ (0.25)
Diluted - Class A common stock (in dollars per share) $ (0.28) $ (0.18) $ (0.47) $ (0.25)
Weighted-average common shares outstanding - basic - Class A common stock (in shares) 176,224,404 140,085,498 173,295,347 139,103,193
Weighted-average common shares outstanding - diluted - Class A common stock (in shares) 176,224,404 140,085,498 173,295,347 139,103,193
v3.26.1
Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Statement of Comprehensive Income [Abstract]        
Net loss $ (48,536) $ (24,685) $ (81,601) $ (34,495)
Other comprehensive loss:        
Unrealized loss on marketable debt securities (2,551) (329) (5,212) (890)
Total comprehensive loss $ (51,087) $ (25,014) $ (86,813) $ (35,385)
v3.26.1
Condensed Consolidated Statements of Stockholders’ Equity (Unaudited) - USD ($)
$ in Thousands
Total
Issuance of common stock in at-the-market offering, net of offering costs
Issuance of common stock in connection with public offering, net of offering costs
Common Stock
Common Stock
Issuance of common stock in at-the-market offering, net of offering costs
Common Stock
Issuance of common stock in connection with public offering, net of offering costs
Common Stock
Restricted Stock
Additional Paid-In Capital
Additional Paid-In Capital
Issuance of common stock in at-the-market offering, net of offering costs
Additional Paid-In Capital
Issuance of common stock in connection with public offering, net of offering costs
Accumulated Deficit
Accumulated Other Comprehensive Income
Beginning balance of the period (in shares) at Dec. 31, 2024       137,706,596                
Balance as of beginning of the period at Dec. 31, 2024 $ 250,857     $ 14       $ 383,739     $ (135,109) $ 2,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Exercise of stock options (in shares)       318,921                
Exercise of stock options 720             720        
Issuance of stock in connection with acquisition of business (in shares)       820,840     274,339          
Issuance of stock in connection with acquisition of business 27,408             27,408        
Common stock withheld for taxes (in shares)       (66,724)                
Common stock withheld for taxes (1,595)             (1,595)        
Issuance of common stock (in shares)             134,832          
Stock-based compensation 2,311             2,311        
Change in unrealized loss on marketable debt securities (561)                     (561)
Net loss (9,810)                   (9,810)  
Ending balance of the period (in shares) at Mar. 31, 2025       139,188,804                
Balance as of end of the period at Mar. 31, 2025 269,330     $ 14       412,583     (144,919) 1,652
Beginning balance of the period (in shares) at Dec. 31, 2024       137,706,596                
Balance as of beginning of the period at Dec. 31, 2024 $ 250,857     $ 14       383,739     (135,109) 2,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Common stock withheld for taxes (in shares) (66,724)                      
Issuance of common stock (in shares) 1,016,098                      
Issuance of common stock $ 1,348                      
Change in unrealized loss on marketable debt securities (890)                      
Net loss (34,495)                      
Ending balance of the period (in shares) at Jun. 30, 2025       147,595,514,000                
Balance as of end of the period at Jun. 30, 2025 696,411     $ 15       864,677     (169,604) 1,323
Beginning balance of the period (in shares) at Mar. 31, 2025       139,188,804                
Balance as of beginning of the period at Mar. 31, 2025 269,330     $ 14       412,583     (144,919) 1,652
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Exercise of stock options (in shares)       697,177                
Exercise of stock options $ 628             628        
Issuance of common stock (in shares) 697,177         7,666,667 42,866          
Issuance of common stock $ 628   $ 440,102     $ 1       $ 440,101    
Stock-based compensation 11,365             11,365        
Change in unrealized loss on marketable debt securities (329)                     (329)
Net loss (24,685)                   (24,685)  
Ending balance of the period (in shares) at Jun. 30, 2025       147,595,514,000                
Balance as of end of the period at Jun. 30, 2025 $ 696,411     $ 15       864,677     (169,604) 1,323
Beginning balance of the period (in shares) at Dec. 31, 2025 160,514,103     160,514,103                
Balance as of beginning of the period at Dec. 31, 2025 $ 1,476,210     $ 16       1,715,787     (240,772) 1,179
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Exercise of stock options (in shares)       290,908                
Exercise of stock options 737             737        
Common stock withheld for taxes (in shares)       (1,280)                
Common stock withheld for taxes (75)             (75)        
Issuance of common stock (in shares)         12,376,352   687,756          
Issuance of common stock   $ 1,181,897     $ 1       $ 1,181,896      
Stock-based compensation 15,586             15,586        
Change in unrealized loss on marketable debt securities (2,661)                     (2,661)
Net loss (33,065)                      
Ending balance of the period (in shares) at Mar. 31, 2026       173,867,839                
Balance as of end of the period at Mar. 31, 2026 $ 2,638,629     $ 17       2,913,931     (273,837) (1,482)
Beginning balance of the period (in shares) at Dec. 31, 2025 160,514,103     160,514,103                
Balance as of beginning of the period at Dec. 31, 2025 $ 1,476,210     $ 16       1,715,787     (240,772) 1,179
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Common stock withheld for taxes (in shares) (1,280)                      
Issuance of common stock (in shares) 651,612 23,088,406                    
Issuance of common stock $ 1,597                      
Change in unrealized loss on marketable debt securities (5,212)                      
Net loss $ (81,601)                      
Ending balance of the period (in shares) at Jun. 30, 2026 185,090,155     185,090,155                
Balance as of end of the period at Jun. 30, 2026 $ 3,273,557     $ 18       3,599,945     (322,373) (4,033)
Beginning balance of the period (in shares) at Mar. 31, 2026       173,867,839                
Balance as of beginning of the period at Mar. 31, 2026 2,638,629     $ 17       2,913,931     (273,837) (1,482)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Exercise of stock options (in shares)       360,704                
Exercise of stock options $ 860             860        
Issuance of common stock (in shares) 360,704       10,712,054   149,558          
Issuance of common stock $ 860 $ 670,047     $ 1       $ 670,046      
Stock-based compensation 15,108             15,108       0
Change in unrealized loss on marketable debt securities (2,551)                     (2,551)
Net loss $ (48,536)                   (48,536)  
Ending balance of the period (in shares) at Jun. 30, 2026 185,090,155     185,090,155                
Balance as of end of the period at Jun. 30, 2026 $ 3,273,557     $ 18       $ 3,599,945     $ (322,373) $ (4,033)
v3.26.1
Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Cash flows from operating activities:    
Net loss $ (81,601,000) $ (34,495,000)
Adjustments to reconcile net loss to net cash used in operating activities:    
Depreciation and amortization 500,000 249,000
Interest income and accretion of discount on marketable debt securities, net 891,000 (342,000)
Stock-based compensation 29,944,000 13,676,000
Deferred income tax expense (credit) 2,000 (4,734,000)
Other 9,000 0
Change in operating assets and liabilities, net of effect of acquisitions:    
Prepaid expenses and other current assets (10,798,000) (4,013,000)
Accounts receivable 517,000 0
Other assets (17,513,000) (21,000)
Accounts payable 3,263,000 (2,456,000)
Accrued expenses and other 9,343,000 1,390,000
Operating lease right-of-use assets and liabilities 33,000 32,000
Other liabilities (49,000) 0
Net cash used in operating activities (65,459,000) (30,714,000)
Cash flows from investing activities:    
Purchases of property, plant and equipment (126,901,000) (1,209,000)
Purchases of marketable debt securities (1,176,421,000) (346,604,000)
Proceeds from redemptions of marketable debt securities 432,827,000 68,017,000
Payment for acquisition of businesses, net of cash acquired 25,736,000 900,000
Other investments (16,500,000) 0
Net cash used in investing activities (912,731,000) (280,696,000)
Cash flows from financing activities:    
Payment of taxes from common stock withheld (75,000) (1,595,000)
Proceeds from exercise of stock options 1,597,000 1,348,000
Payment of offering costs and deferred issuance costs 0 (304,000)
Payment of finance lease liability (750,000) 0
Payment of debt (1,367,000) 0
Proceeds from sale of common stock, net of offering costs 1,851,944,000 441,600,000
Net cash provided by financing activities 1,851,349,000 441,049,000
Net increase in cash, cash equivalents and restricted cash 873,159,000 129,639,000
Cash, cash equivalents and restricted cash - beginning of period 788,445,000 97,132,000
Cash, cash equivalents and restricted cash - end of period 1,661,604,000 226,771,000
Cash, cash equivalents, and restricted cash    
Cash and cash equivalents 1,644,704,000 226,771,000
Restricted cash 8,400,000 0
Restricted cash, noncurrent portion 8,500,000 0
Total cash, cash equivalents, and restricted cash 1,661,604,000 226,771,000
Supplemental disclosures of cash flow information:    
Cash paid for interest 54,000 0
Cash paid for income taxes 0 660,000
Supplemental noncash investing and financing activities:    
Issuance of common stock in connection with acquisition of business 0 27,408,000
Assumed liabilities in connection with acquisition of businesses 3,585,000 287,000
Purchases of property, plant and equipment in accounts payable and accrued expense and other 9,008,000 1,509,000
Offering costs included in accounts payable 0 1,132,000
Offering costs included in accrued expense and other 0 62,000
Holdback liabilities in connection with the acquisition of businesses 4,066,000 0
Contingent consideration in connection with the acquisition of business 3,110,000 0
Settlement of accounts payable in connection with acquisition of businesses $ 564,000 $ 0
v3.26.1
Nature of Operations and Organization
 6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Nature of Operations and Organization Nature of Operations and Organization
Oklo Inc. (the "Company" or "Oklo"), a Delaware corporation, and its subsidiaries are developing advanced fission power plants to provide clean, reliable, and affordable energy at scale. Oklo Technologies, Inc., a Delaware corporation and wholly owned subsidiary of Oklo Inc., was incorporated on July 3, 2013.

The Company plans to commercialize its metal-fueled fast reactor technology with the Aurora powerhouse product line. The Aurora powerhouse product line is designed to produce between 15 and 75 megawatts of electricity (“MWe”) on fresh, recycled, or down-blended nuclear fuel. Advanced fission technology is built on a deep history of successful operation, first demonstrated by the Experimental Breeder Reactor-II (“EBR-II”), which sold and supplied power to the grid and showed effective used nuclear fuel recycling capabilities over 30 years of operation. The Company is also commercializing nuclear fuel recycling and fuel fabrication technology that can convert used nuclear fuel and other nuclear materials into usable fuel for its reactors, as well as the production of radioisotopes. The Company’s radioisotope activities are intended to support domestic supply for medical, industrial, space, defense, and other critical applications. The Company is pursuing these activities through dedicated isotope production and processing capabilities, which may also benefit from radioisotope co-products generated through its fuel recycling and reactor platform. In addition, the Company is expanding its capabilities in precision manufacturing, prototyping, and chemical process engineering through recent acquisitions in support of its power, fuel, and isotope projects. For more information about the Company’s recent acquisitions, see Note 3—Business Combination—2026 Acquisitions.

Liquidity and Capital Resources

As of June 30, 2026, the Company’s cash, cash equivalents, and marketable debt securities were $3,006,289. The Company continues to incur significant operating losses. For the six months ended June 30, 2026, the Company had a net loss of $81,601, loss from operations of $124,166, and net cash used in operating activities of $65,459. As of June 30, 2026, the Company had an accumulated deficit of $322,373.

The Company expects to utilize its existing cash, cash equivalents, and marketable debt securities to fund construction of its powerhouses, fuel and radioisotope businesses as well as maintain its ongoing operations and growth plans and believes that its existing cash, cash equivalents, and marketable debt securities will be sufficient to fund its operations for the one-year period following the issuance date of these unaudited condensed consolidated financial statements.
v3.26.1
Summary of Significant Accounting Policies
 6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies Summary of Significant Accounting Policies
Basis of Presentation

The accompanying unaudited condensed consolidated financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial reporting.

The accompanying unaudited condensed consolidated financial statements and footnote disclosures have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information or footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted, pursuant to the rules and regulations of the SEC for interim financial reporting. Accordingly, they do not include all the information and footnotes necessary for a complete presentation of financial position, results of operations, or cash flows. The information herein should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was filed on March 17, 2026. In the opinion of management, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting of a normal recurring nature, which are necessary for a fair statement of the financial position, operating results, and cash flows for the periods presented.
Restricted Cash

Restricted cash consists of cash balances that are subject to restrictions on withdrawal or use. Such amounts are not available for general corporate purposes and may be restricted pursuant to contractual, regulatory, or other arrangements.

Accounts Receivable

Accounts receivable are recorded at the invoiced amount and include amounts earned but not yet billed to customers, net of expected credit losses. The Company estimates expected credit losses based on historical experience and current conditions. The allowance for credit losses was not material as of June 30, 2026 and December 31, 2025.

Revenue Recognition

The Company recognizes revenue in a manner to depict the transfer of goods or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for goods or services. Revenue is recognized when control of the promised good or service is transferred to the customer. Depending on the terms of the arrangement, revenue may be recognized either over time or at a point in time.

During the three and six months ended June 30, 2026, the Company generated revenue primarily from engineering and consulting services, manufacturing and fabrication services, and other ancillary service arrangements. For revenue recognized over time, the Company utilizes input methods based on the expected remaining output of the contract to recognize revenue. The Company determined this is the most faithful depiction of the transfer of goods or services as it is based on the expected remaining effort to deliver under the contracts.

For certain milestone-based contracts, individual contractual deliverables or milestones may represent distinct performance obligations. Revenue associated with these arrangements is generally recognized at a point in time when control of the related good or service transfers to the customer, which may occur upon delivery, customer acceptance, or satisfaction of other contractual criteria.

Disaggregation of Revenue

The following table presents revenue disaggregated by nature of revenue stream for the periods presented:
Three and Six Months Ended June 30,
20262025
Engineering and consulting services
$800 $— 
Manufacturing and fabrication services
168 — 
Other
242 — 
Total revenue recognized
$1,210 $— 

Contract Balances

Contract assets arise when revenue is recognized before the Company obtains an unconditional right to consideration and generally result from revenue recognized in advance of customer billings. Contract liabilities represent customer prepayments received in advance of satisfying related performance obligations and are recognized as revenue as the Company fulfills those obligations.

The following table presents contract balances for the periods presented:
As of
June 30, 2026
(unaudited)		December 31, 2025
Contract assets
$2,402 $— 
Contract liabilities
53 — 

Contract assets are included within prepaid expenses and other current assets on the condensed consolidated balance sheets. Contract liabilities are included within other current liabilities on the condensed consolidated balance sheets.
The changes in contract assets and contract liabilities during the period ended June 30, 2026, were primarily attributable to the Company's acquisitions. For additional information about the acquisitions, see Note 3—Business Combinations—2026 Acquisitions.

The Company has elected not to disclose information about remaining performance obligations for (i) contracts with an original expected duration of one year or less and (ii) contracts for which revenue is recognized using the right-to-invoice practical expedient, whereby the amount invoiced corresponds directly with the value of the Company's performance completed to date. As of June 30, 2026, remaining performance obligations not subject to these exceptions were not material.

Cost of Sales

Cost of sales includes direct costs incurred in satisfying performance obligations under customer contracts.

Segment Information

The Company has viewed its financial information on an aggregate basis for the purposes of evaluating financial performance and allocating the Company’s resources. The Company’s principal business consists primarily of research and development and deployment activities for its planned or in-process powerhouses, nuclear fuel recycling and fuel fabrication facilities, and its radioisotope production facilities. Accordingly, the Company has determined that it conducts its business in one operating and reportable segment. For more information about the Company’s single operating and reportable segment, see Note 12—Segment Information.
Principles of Consolidation

The unaudited condensed consolidated financial statements include the Company’s accounts and those of its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated.
Use of Estimates

Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, judgments, and assumptions that affect the amounts reported and disclosed in the unaudited condensed consolidated financial statements and accompanying notes. Actual results could differ materially from these estimates. On an ongoing basis, the Company evaluates its estimates, including those related to the valuation of operating lease liabilities and operating right-of-use assets, useful lives of property, plant and equipment, valuation allowance on deferred tax assets, and the fair value of acquired intangible assets and goodwill. These estimates, judgments, and assumptions are based on current and expected economic conditions, historical data, and experience available at the date of the accompanying unaudited condensed consolidated financial statements, and various other factors that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Risk and Uncertainties

The Company is subject to continuing risks and uncertainties amidst a range of supply chain, construction, and design complexities and in connection with the market dynamics around fuel costs and the current macroeconomic environment, including as a result of inflation, instability in the global banking system, trade policy (including tariffs, export controls, and sanctions), ongoing or escalating geopolitical factors and military activities, as well as the potential for additional conflicts, war or civil unrest. At this point, the extent to which these effects may impact the Company’s future financial condition or results of operations is uncertain, and as of the date of issuance of these unaudited condensed consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the update of any estimates or judgments or an adjustment of the carrying value of any assets or liabilities. These estimates may change as new events occur and additional information is obtained and will be recognized in the financial statements as soon as they become known.
Net Loss Per Common Share

The Company’s basic net loss per share of common stock is computed based on the average number of outstanding shares of common stock for the period, by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share of common
stock is computed by dividing net loss by the weighted-average number of shares of common stock and common share equivalents of potentially dilutive securities outstanding for the period. Potentially dilutive securities include common stock equivalents. Since the Company was in a loss position for the periods presented, basic net loss per share of common stock is the same as diluted net loss per share of common stock since the effects of potentially dilutive securities are antidilutive.

The outstanding potentially dilutive common stock equivalents as of June 30, 2026 and 2025 consisting of: (1) options to purchase shares of common stock of 5,738,353 and 8,430,096, respectively, (2) unvested restricted stock of 373,406 and 640,125, respectively, and (3) unvested restricted stock units of 3,525,985 and 2,337,546, respectively, have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect.

Emerging Growth Company Status

The Company is classified as an emerging growth company (“EGC”), as defined under the Jumpstart Our Business Startups Act. Therefore, the Company may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not EGCs. The Company will retain EGC status until December 31, 2026.

Recently Issued and Not Adopted Accounting Standards

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which will require disaggregated disclosures in the notes to the financial statements of certain categories of expenses, including purchases of inventory, employee compensation, and depreciation and amortization, that are included in expense line items within the statement of operations. ASU 2024-03 will be applied prospectively; however, retrospective application is permitted. ASU 2024-03, as clarified in ASU 2025-01, Clarifying the Effective Date, is effective for the Company's annual reporting period ending December 31, 2027. Early adoption is permitted. The Company is evaluating the impact of ASU 2024-03 on its disclosures in the notes to its financial statements.

In September 2025, the FASB issued ASU 2025‑06, Intangibles—Goodwill and Other—Internal‑Use Software (Subtopic 350‑40): Targeted Improvements to the Accounting for Internal‑Use Software, which updates the guidance for capitalization of internal‑use software costs, including clarifications to the criteria for capitalizing configuration, development, and implementation activities. ASU 2025-06 is effective for the Company beginning with interim reporting for fiscal year 2029. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2025-06 on its accounting policies and related disclosures.

In December 2025, the FASB issued ASU 2025‑10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which provides updated guidance on how to recognize, measure, and present government grants. ASU 2025‑10 is effective for the Company for annual periods beginning after December 15, 2028, including interim periods within those periods using a modified prospective, modified retrospective, or full retrospective transition approach. Early adoption is permitted. The Company is currently assessing the effect of ASU 2025-10 on its financial statements.
v3.26.1
Business Combinations
 6 Months Ended
Jun. 30, 2026
Business Combination [Abstract]  
Business Combinations Business Combinations
2026 Acquisitions

On June 4, 2026, the Company acquired ARMEC, LLC and its affiliated entity equity interests in a business combination for its U.S.-based precision manufacturing and mechanical engineering expertise specializing in high-precision machining and prototyping for the nuclear industry for aggregate consideration of $20,462, consisting of (i) $15,857 of cash consideration, (ii) $1,700 of purchase price holdback amounts subject to purchase price adjustments and indemnification claims, which has been adjusted for settlement of preexisting relationships, and (iii) $3,110 of earnout contingent consideration recorded at fair value, subject to a potential maximum payment of $5,000, see Note 6—Financial Instruments for additional details.

On June 15, 2026, the Company acquired Creative Engineers, Inc. in a business combination for its U.S.-based chemical process engineering expertise in sodium and alkali-metal systems for the nuclear industry for aggregate consideration of $12,918, consisting of (i) $10,911 of cash consideration and (ii) $2,000 of purchase price holdback amounts subject to purchase price adjustments and indemnification claims, which has been adjusted for settlement of preexisting relationships.
As of June 30, 2026, the accounting for the acquisitions is preliminary, and the amounts recognized in these financial statements are provisional. The Company is continuing to finalize certain working capital adjustments and fair value estimates of assets acquired and liabilities assumed. The Company expects to finalize the fair values of the assets acquired and liabilities assumed during the one-year measurement period.

The composition of the preliminary purchase price is as follows:
Cash$26,768 
Purchase price holdback amounts, net4,066 
Contingent consideration3,110 
Settlement of preexisting relationships(564)
Total purchase consideration$33,380 

The Company incurred $575 in transaction costs related to the acquisitions, which primarily consisted of legal and accounting expenses. The acquisition-related expenses were recorded in general and administrative expenses on the condensed consolidated statements of operations.

The preliminary purchase price allocation resulted in the following amounts being allocated to the assets acquired and liabilities assumed at the acquisition dates based upon their respective fair values as summarized below:
Cash$1,032 
Accounts receivable2,496 
Prepaid expenses and other current assets2,437 
Property, plant and equipment3,966 
Operating lease right-of-use assets320 
Intangible assets16,800 
Goodwill9,914 
Accounts payable(205)
Accrued expenses and other(716)
Other current liabilities(102)
Operating lease liability(320)
Debt(2,242)
Net assets acquired$33,380 

Intangible assets acquired, consisting of customer relationships with a weighted average useful life of 10.9 years, and trade names with a weighted-average useful life of 8.5 years, are included in intangible assets, net on the condensed consolidated balance sheets. Goodwill recognized is primarily attributable to the assembled workforce, expected synergies and other future economic benefits of the acquired businesses. The goodwill arising from the acquisitions is deductible for tax purposes.

Pro forma results of operations for these business combinations have not been presented because they are not material to the consolidated results of operations, either individually or in aggregate.

The results of operations for the acquisitions are included in the condensed consolidated financial statements beginning on their respective acquisition dates. For the three and six months ended June 30, 2026, revenue and net loss attributable to the acquisitions that were included in the Company's condensed consolidated statements of operations were $968 and $42, respectively.

2025 Acquisitions

On February 28, 2025 (the “Acquisition Date”), the Company acquired Atomic Alchemy Inc.’s ("Atomic Alchemy") common stock in a business combination for its radioisotope business located in the U.S. The purchase price of $28,424 was comprised of (i) a cash portion of $900, net of cash acquired, paid at the Acquisition Date to certain Atomic Alchemy equity holders for their respective portion of the consideration, and (ii) the issuance of 820,840 shares of the Company’s common stock representing stock consideration in exchange for Atomic Alchemy’s common stock. At the Acquisition
Date, the Company’s common stock public trading price of $33.39 per share was used to measure the stock consideration of $27,408.

In connection with the business combination, the Company issued 274,339 shares of its common stock, subject to certain lock-up provisions, vesting conditions, and substantial risk of forfeiture, representing post-combination services, pursuant to an employment agreement and vesting agreement.

The composition of the purchase price is as follows:
Cash$1,016 
Common stock27,408 
Total purchase consideration$28,424 

The Company incurred $410 in transaction costs related to the acquisition, which primarily consisted of legal and accounting expenses. The acquisition-related expenses were recorded in general and administrative expenses on the condensed consolidated statements of operations.

During the fourth quarter of 2025, the Company adjusted the purchase price allocation as a result of certain measurement period adjustments to the acquired assets and liabilities assumed. The Company finalized its measurement period accounting after filing Atomic Alchemy's short year 2025 federal and state income tax returns, and following revisions to internal estimates and new information obtained about facts and circumstances that existed as of the Acquisition Date. The measurement period adjustments included a decrease in deferred tax liabilities of $99 with a corresponding decrease to goodwill.

The purchase price allocation resulted in the following amounts being allocated to the assets acquired and liabilities assumed at the Acquisition Date based upon their respective fair values as summarized below:
Cash$116 
Prepaid expenses99 
Property and equipment40 
Operating lease right-of-use assets19 
Indefinite-lived intangible assets27,500 
Goodwill6,621 
Operating lease liability(19)
Other current liabilities(268)
Deferred tax liabilities(5,684)
Net assets acquired
$28,424 

The Company utilized an independent appraisal firm to assist in the determination of the fair values of the assets acquired and liabilities assumed, which required certain significant management assumptions and estimates. The fair value of the indefinite-lived intangible assets representing in-process research and development ("IPR&D") were valued using a pre-tax royalty for the hypothetical use of a trade name for a selected royalty rate based on a market licensing agreement benchmarking analysis.

The IPR&D consisted of two separate projects, Abundantia and Meitner. Abundantia’s fair value assigned of $4,600 is expected to produce revenue in 2027 from the sale of purified radium and other desired radioisotopes produced via irradiation. Meitner’s fair value of $22,900 is a later stage project which will produce for sale isotopes that are prepared and irradiated into radioisotopes in Versatile Isotope Production Reactors (“VIPR”), which is a thermal pool-type nuclear reactor. Each project has a different risk profile, cash flows, and its own unique process. Abundantia's fair value was determined using a risk-adjusted cash flow approach applied to its potential cash flows, subject to obtaining a certain material handling permit required by the NRC. Meitner is expected to produce revenue once a facility is constructed, with its fair value determined using a risk-adjusted cash flow approach applied to its cash flows, subject to approval of an application for a construction license and operating license by the NRC. There was no estimated useful life assigned given the assets are IPR&D. The IPR&D is included in intangible assets, net on the condensed consolidated balance sheets.

The excess of the purchase price over the fair value amounts assigned to the assets acquired and liabilities assumed represents goodwill from the acquisition. Goodwill is recorded as a noncurrent asset that is not amortized but is subject to
an annual review for impairment. The goodwill arising from the acquisition of Atomic Alchemy is not deductible for tax purposes.

The results of operations of Atomic Alchemy are included in the condensed consolidated financial statements beginning on the Acquisition Date.
v3.26.1
Balance Sheet Components
 6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Balance Sheet Components Balance Sheet Components
Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets are summarized as follows:
As of
June 30, 2026
(unaudited)		December 31, 2025
Prepaid expenses$15,079 $18,853 
Accrued interest receivable10,273 4,976 
Other20,020 1,969 
Total prepaid expenses and other current assets$45,372 $25,798 

Prepaid expenses include prepaid consulting fees, insurance premiums, rent and other charges, and construction deposits.

Prepaid expenses are amortized on a straight-line basis over the related contract term. Construction deposits consist of advance payments for long-lived assets related to capital projects and are recorded within current assets until the related construction activities are performed. Upon performance of the construction activities, the construction deposits are reclassified to construction in progress. Cash outflows associated with construction deposits are presented as purchases of property, plant and equipment within investing activities in the condensed consolidated statements of cash flows.

Property, Plant and Equipment, Net

Property, plant and equipment, net are summarized as follows:
As of
Estimates Useful Lives (Years)June 30, 2026
(unaudited)		December 31, 2025
Computers and equipment
3 - 7
$740 $366 
Furniture, fixtures and machinery72,796 483 
Software31,405 1,405 
Leasehold improvements*255 62 
Land and buildings407,182 5,145 
Total property, plant and equipment, gross12,378 7,461 
Less: accumulated depreciation and amortization(1,300)(897)
Construction in progress and equipment deposits165,117 35,748 
Total property, plant and equipment, net$176,195 $42,312 
* Shorter of lease term or estimated useful life of the asset.

Included in property, plant, and equipment is construction in progress and equipment deposits. Costs related to construction of capital projects are accumulated in construction in progress and equipment deposits until the project is complete, as well as equipment that is not yet placed in service. A construction project is considered substantially complete upon the cessation of construction and development activities. Once the project is substantially complete and ready for its intended use, the costs will be depreciated over the asset’s estimated useful life.

Depreciation and amortization expenses for the three months ended June 30, 2026 and 2025 totaled $240 and $125, respectively. Depreciation and amortization expenses for the six months ended June 30, 2026 and 2025 totaled $403 and $249, respectively.
Intangible Assets

Intangible assets are summarized as follows:

As of
Estimated Useful Lives (Years)June 30, 2026
(unaudited)		December 31, 2025
IPR&DN/A$27,500 $27,500 
Customer relationships10.916,000 — 
Trade names8.5800 — 
Total intangible assets44,300 27,500 
Less: accumulated amortization(97)— 
Total intangible assets, net$44,203 $27,500 

Amortization expense was $97 for the three and six months ended June 30, 2026. There was no amortization expense for the three and six months ended June 30, 2025.

Other Assets

Other assets are summarized as follows:
As of
June 30, 2026
(unaudited)		December 31, 2025
Finance lease right-of-use asset$933 $— 
Prepayments17,730217 
Other investments28,586 12,086 
Total other assets$47,249 $12,303 
As of June 30, 2026 and December 31, 2025, the Company’s other investments primarily consist of simple agreements for future equity and preferred equity investments in privately held companies. These investments are recorded at cost, as they do not have readily determinable fair values. As of June 30, 2026, management did not identify any impairment indicators or observable transactions that would require an adjustment to carrying value.
Accrued Expenses and Other

Accrued expenses and other are summarized as follows:
As of
June 30, 2026
(unaudited)		December 31, 2025
Accrued professional fees$2,689 $1,838 
Accrued payroll and bonuses11,160 10,998 
General accrued expenses20,754 7,210 
Contingent consideration1,880 — 
Other1,540 451 
Total accrued expenses and other$38,023 $20,497 
v3.26.1
Leases
 6 Months Ended
Jun. 30, 2026
Leases [Abstract]  
Leases Leases
As of June 30, 2026, the Company had commercial real estate lease agreements for office space under operating leases and land under a finance lease.

The table below presents supplemental information related to the operating and finance leases:
Six Months Ended June 30,
20262025
Cash payments included in the measurement of operating lease liabilities during the period$637 $376 
Cash payments included in the measurement of finance lease liability during the period750 — 
Operating lease liabilities arising from obtaining lease right-of-use assets during the period2,016 1,142 
Finance lease liability arising from obtaining lease right-of-use asset during the period933 — 

Weighted average remaining lease terms and weighted average discount rates were as follows as of June 30, 2026:
Operating LeasesFinance Lease
Weighted-average remaining lease term (in years) as of period-end
3.414.8
Weighted-average discount rate during the period8.94%9.50%

The Company utilizes an estimated incremental borrowing rate on a collateralized basis, reflecting the term of the lease and the Company’s credit profile at the commencement of the lease in determining the present value of future payments since the implicit rate for the Company’s leases is not readily determinable.

Variable lease expense includes lease payments that vary based on usage or performance and are not fixed at lease commencement. Payments for services such as maintenance, utilities, and real estate taxes are accounted for as non-lease components and expensed as incurred.

Finance lease right-of-use asset is included within other assets on the condensed consolidated balance sheets. Finance lease liability of $187 is included within other liabilities on the condensed consolidated balance sheets.

The components of operating and finance lease costs were as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Operating lease costs included in:
Research and development$1,486 $212 $1,746 $363 
General and administrative742 106 847 186 
Total operating costs (1)
2,228 318 2,593 549 
Finance lease cost:
Interest on lease liabilities4 — 4 — 
Total lease cost$2,232 $318 $2,597 $549 

(1) Month-to-month lease arrangements for the three months ended June 30, 2026 and 2025 of $1,865 and $80, respectively, and six months ended June 30, 2026 and 2025 of $1,922 and $151, respectively, are included in the captions within operating lease costs.

The minimum lease payments below do not include non-lease components, which are contractual obligations under the Company’s lease, but are not fixed and can fluctuate from period to period and are expensed as incurred.
As of June 30, 2026, future maturities of the operating and finance lease liabilities were as follows:
Operating Leases
Finance Lease
2026 (remaining of year)$801 $— 
2027901 — 
2028910 — 
2029793 — 
2030270 — 
Thereafter125 750 
Minimum lease payments3,800 750 
Less imputed interest(541)(563)
Present value of lease liabilities$3,259 $187 
Current portion of lease liabilities$1,025 $— 
Noncurrent portion of lease liabilities2,234 187 
Total lease liabilities$3,259 $187 
Leases Leases
As of June 30, 2026, the Company had commercial real estate lease agreements for office space under operating leases and land under a finance lease.

The table below presents supplemental information related to the operating and finance leases:
Six Months Ended June 30,
20262025
Cash payments included in the measurement of operating lease liabilities during the period$637 $376 
Cash payments included in the measurement of finance lease liability during the period750 — 
Operating lease liabilities arising from obtaining lease right-of-use assets during the period2,016 1,142 
Finance lease liability arising from obtaining lease right-of-use asset during the period933 — 

Weighted average remaining lease terms and weighted average discount rates were as follows as of June 30, 2026:
Operating LeasesFinance Lease
Weighted-average remaining lease term (in years) as of period-end
3.414.8
Weighted-average discount rate during the period8.94%9.50%

The Company utilizes an estimated incremental borrowing rate on a collateralized basis, reflecting the term of the lease and the Company’s credit profile at the commencement of the lease in determining the present value of future payments since the implicit rate for the Company’s leases is not readily determinable.

Variable lease expense includes lease payments that vary based on usage or performance and are not fixed at lease commencement. Payments for services such as maintenance, utilities, and real estate taxes are accounted for as non-lease components and expensed as incurred.

Finance lease right-of-use asset is included within other assets on the condensed consolidated balance sheets. Finance lease liability of $187 is included within other liabilities on the condensed consolidated balance sheets.

The components of operating and finance lease costs were as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Operating lease costs included in:
Research and development$1,486 $212 $1,746 $363 
General and administrative742 106 847 186 
Total operating costs (1)
2,228 318 2,593 549 
Finance lease cost:
Interest on lease liabilities4 — 4 — 
Total lease cost$2,232 $318 $2,597 $549 

(1) Month-to-month lease arrangements for the three months ended June 30, 2026 and 2025 of $1,865 and $80, respectively, and six months ended June 30, 2026 and 2025 of $1,922 and $151, respectively, are included in the captions within operating lease costs.

The minimum lease payments below do not include non-lease components, which are contractual obligations under the Company’s lease, but are not fixed and can fluctuate from period to period and are expensed as incurred.
As of June 30, 2026, future maturities of the operating and finance lease liabilities were as follows:
Operating Leases
Finance Lease
2026 (remaining of year)$801 $— 
2027901 — 
2028910 — 
2029793 — 
2030270 — 
Thereafter125 750 
Minimum lease payments3,800 750 
Less imputed interest(541)(563)
Present value of lease liabilities$3,259 $187 
Current portion of lease liabilities$1,025 $— 
Noncurrent portion of lease liabilities2,234 187 
Total lease liabilities$3,259 $187 
v3.26.1
Financial Instruments
 6 Months Ended
Jun. 30, 2026
Investments, Debt and Equity Securities [Abstract]  
Financial Instruments Financial Instruments
The following table shows the Company’s cash, cash equivalents and marketable debt securities by significant investment category:
As of June 30, 2026
Amortized CostUnrealized Gains
Unrealized Losses (1)
Fair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $— $57,623 $— $— 
Level 1:
Money market funds— — — — 1,571,094 — — 
U.S. Treasury securities1,244,182 61 (4,041)1,240,202 — 699,071 541,131 
Subtotal1,244,182 61 (4,041)1,240,202 1,571,094 699,071 541,131 
Level 2 (2):
Commercial paper137,423 — (53)137,370 15,987 121,383 — 
Total $1,381,605 $61 $(4,094)$1,377,572 $1,644,704 $820,454 $541,131 

(1) There was no allowance for expected credit losses on available-for-sale marketable debt securities as of June 30, 2026 as the unrealized losses were deemed to be temporary in nature.

(2) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.

As of June 30, 2026, interest receivables related to available-for-sale marketable debt securities of $4,896 were included in marketable debt securities on the condensed consolidated balance sheets.

As of June 30, 2026, interest receivables related to marketable debt securities of $6,769 were included in prepaid expenses and other current assets on the condensed consolidated balance sheets.

The following table shows the fair value of the Company’s noncurrent marketable debt securities, by contractual maturity, as of June 30, 2026:

Due within 1 year$820,454 
Due after 1 year through 5 years541,131 
Total fair value$1,361,585 

The following tables show the Company’s cash, cash equivalents, and marketable debt securities by significant investment category:
As of December 31, 2025
Amortized CostUnrealized GainsFair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $11,022 $— $— 
Level 1:
Money market funds— — — 777,423 — — 
U.S. Treasury securities504,008 1,123 505,131 — 320,563 184,568 
Subtotal504,008 1,123 505,131 777,423 320,563 184,568 
Level 2 (1):
Commercial paper118,907 56 118,963 — 118,963 — 
Total$622,915 $1,179 $624,094 $788,445 $439,526 $184,568 

(1) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.

As of December 31, 2025, interest receivables related to available-for-sale marketable debt securities of $4,005 were included in marketable debt securities on the condensed consolidated balance sheets.

As of December 31, 2025, interest receivables related to marketable debt securities of $3,160 were included in prepaid expenses and other current assets on the condensed consolidated balance sheets.

The following table presents the fair value of the Company's contingent consideration measured on a recurring basis as of June 30, 2026:

Fair ValueQuoted Prices in Active Markets for Identical Assets (Level 1)Significant Other Observable Inputs (Level 2)Significant Unobservable Inputs (Level 3)
Contingent consideration$3,110 $— $— $3,110 

The fair value of the contingent consideration was determined using an option pricing model based on the probability of achieving the earnout targets over the two-year earnout period. The contingent consideration is classified as a Level 3 fair value measurement due to the use of significant unobservable inputs, which include a calculated discount rate and expected revenue volatility. No material changes or assumptions relating to the estimated fair value of the contingent consideration were identified during the period. As of June 30, 2026, the current portion of $1,880 is reflected in accrued expenses and other and $1,230 is reflected in other liabilities on the condensed consolidated balance sheets.
v3.26.1
Right of First Refusal Liability
 6 Months Ended
Jun. 30, 2026
Commitments and Contingencies Disclosure [Abstract]  
Right of First Refusal Liability Right of First Refusal Liability
On February 16, 2024, the Company entered into a letter of intent (the “LOI”) with an unrelated third party (the “third party”) for the purchase of power from the Company’s planned powerhouses to serve certain data centers in the U.S. on a 20-year timeline with the right to renew for additional 20-year terms, and at a rate to be formally specified in one or more future power purchase agreements ("PPA") (subject to the requirement that the price meets certain conditions contained in the agreement).

The LOI provides for the third party to have a continuing right of first refusal for a period of thirty-six (36) months following its execution to purchase energy output produced by certain powerhouses developed by the Company in the U.S., subject to certain provisions and excluded powerhouses (the “ROFR”). In exchange for the ROFR and other rights contained in the LOI, in March 2024, the third party paid the Company $25,000 (the “Payment”). In connection with the Payment, the Company agreed to supply power at a discount to the most favored nation pricing that the Company is required to provide to the third party in a future PPA (location to be determined); provided, that pricing set out in a PPA will include an additional discount if needed such that the total savings against most favored nation pricing over the course of the PPA is equivalent to the Payment. The Payment is effectively a nonrefundable upfront payment that will be attributed to future power delivery. As of June 30, 2026 and December 31, 2025, the outstanding balance under the right of first refusal liability was $25,000, as reflected on the condensed consolidated balance sheets.
v3.26.1
Stockholders’ Equity
 6 Months Ended
Jun. 30, 2026
Equity [Abstract]  
Stockholders’ Equity Stockholders’ Equity
Pursuant to the Second Amended and Restated Certificate of Incorporation of the Company, the Company is authorized to issue 501,000,000 shares of all classes of capital stock consisting of (i) 500,000,000 shares of common stock, par value of $0.0001 per share, and (ii) 1,000,000 shares of preferred stock, par value of $0.0001 per share. Subject to the special rights of the holders of any outstanding series of preferred stock, the number of shares of preferred stock may be increased or decreased (but not below the number of shares then outstanding) by affirmative vote of the holders of a majority of the stock of the Company entitled to vote. There are no shares of preferred stock issued and outstanding.

Equity ATM Programs

In December 2025, the Company entered into a sales agreement with sales agents pursuant to which the Company may offer and sell, from time to time and at its sole discretion, shares of its common stock up to an aggregate gross sales price of $1,500,000 in an "at-the-market" offering (the "2025 ATM Program"), which was completed during the period ended March 31, 2026. Under the 2025 ATM Program, the Company agreed to pay the sales agents' commissions at a rate equal to 1.5% of the aggregate gross proceeds from each sale of shares.

In May 2026, the Company entered into a sales agreement with sales agents pursuant to which the Company may offer and sell, from time to time and at its sole discretion, shares of its common stock up to an aggregate gross sales price of $1,000,000 in an "at-the-market" offering (the "2026 ATM Program"), which was ongoing as of June 30, 2026. Under the 2026 ATM Program, the Company agreed to pay the sales agents' commissions at a rate up to 1.5% of the aggregate gross proceeds from each sale of shares.

The following is a summary of the shares issued under the ATM Programs during the six months ended June 30, 2026 (in thousands except shares issued and average price per share):
ATM ProgramsShares IssuedAverage Net Price Per ShareGross ProceedsNet Proceeds
2025 ATM Program12,376,352$96.95$1,199,868 $1,181,897 
2026 ATM Program10,712,054$63.51680,371 670,047 
Total / Average23,088,406$81.44$1,880,239 $1,851,944 

Exercise of Stock Options – During the three and six months ended June 30, 2026, the Company issued shares of its common stock upon the exercise of stock options totaling 360,704 and 651,612, respectively, with proceeds of $860 and $1,597, respectively, as reflected on the condensed consolidated statements of stockholders’ equity. During the three and six months ended June 30, 2025, the Company issued shares of its common stock upon the exercise of stock options totaling 697,177 and 1,016,098, respectively, with proceeds of $628 and $1,348, respectively, as reflected on the condensed consolidated statements of stockholders’ equity.

Restricted Stock Units – The Company issued, in connection with the vesting of restricted stock units, 149,558 and 42,866 shares of the Company’s common stock during the three months ended June 30, 2026 and 2025, respectively, and 837,314 and 177,698 shares of common stock during the six months ended June 30, 2026 and 2025, respectively, as reflected on the condensed consolidated statements of stockholders’ equity.

Common Stock Withheld for Taxes – The Company withheld 1,280 and 66,724 shares of its common stock upon issuance of vested restricted units, representing a payment for taxes of $75 and $1,595, during the six months ended June 30, 2026 and 2025, respectively, as reflected on the condensed consolidated statements of stockholders’ equity.
v3.26.1
Stock-Based Compensation
 6 Months Ended
Jun. 30, 2026
Share-Based Payment Arrangement [Abstract]  
Stock-Based Compensation Stock-Based Compensation
The Company recorded stock-based compensation in the following expense categories in its condensed consolidated statement of operations for employees and non-employees:

Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Research and development$5,603 $3,229 $13,099 $4,202 
General and administrative8,755 8,136 16,845 9,474 
Total costs charged to operations$14,358 $11,365 $29,944 $13,676 

Research and development expenses of $713 and general and administrative expenses of $37 related to construction in progress, were capitalized during the three and six months ended June 30, 2026, respectively. No research and development expenses and general and administrative expenses were capitalized during the three and six months ended June 30, 2025.

During the six months ended June 30, 2026, approximately 1,730,000 restricted stock units were granted to acquire shares of the Company's common stock, with a grant date fair value of approximately $107,000 under its stock-based compensation plan.

Unrecognized compensation costs and expected weighted-average period to be recognized related to the stock-based compensation awards as of June 30, 2026 were as follows:

Restricted StockStock OptionsTotals
Unrecognized stock-based compensation cost$172,870 $12,618 $185,488 
Weighted-average period over which cost is expected to be recognized (in years)3.753.093.70
v3.26.1
Income Taxes
 6 Months Ended
Jun. 30, 2026
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The provision for income taxes in interim periods is determined using an estimate of the Company’s annual effective tax rate ("ETR"), adjusted for discrete items that arise during the period. Each quarter, the Company updates its estimate of its annual ETR, and if the estimated annual ETR changes, the Company makes a cumulative adjustment in such period. The quarterly provision for income taxes, and estimate of the Company’s annual ETR, are subject to variation due to several factors, including variability in pre-tax income (or loss), the mix of jurisdictions to which such income relates, changes in how the Company conducts business, and tax law developments.

The realization of deferred tax assets is dependent upon a variety of factors, including the generation of future taxable income, the reversal of deferred tax liabilities, and tax planning strategies. The Company's provision for income taxes reflects discrete items and jurisdictional tax expense, which may cause fluctuations in the quarterly and year‑to‑date ETR compared to the Company’s statutory tax rate. During the three months ended June 30, 2026, the Company recorded an income tax benefit of $3,153, primarily related to a change in estimated accrual for state income tax expense. During the six months ended June 30, 2026, the Company recorded an income tax expense of $2, primarily related to deferred tax liabilities on long-life assets recognized during the period. During the three months ended June 30, 2025, the Company recorded an income tax expense of $431, and during the six months ended June 30, 2025, the Company recorded an income tax benefit of $3,980, primarily related to discrete items recognized in connection with the acquisition of Atomic Alchemy. Based on the Company's cumulative historical operating losses and uncertainty regarding the generation of future taxable income, a valuation allowance was maintained against all of our deferred tax assets as of June 30, 2026 and 2025.

As of June 30, 2026 and 2025, the Company had unrecognized tax benefits related to federal research credit carryforwards, of which, if fully recognized in the future would have no impact to the ETR and would result in a corresponding adjustment to the valuation allowance. No interest and penalties related to the unrecognized tax benefits are accrued.
v3.26.1
Commitments and Contingencies
 6 Months Ended
Jun. 30, 2026
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies Commitments and Contingencies
Contract Commitments

The Company enters into contracts in the normal course of business with third-party contract research organizations, contract development and manufacturing organizations and other service providers and vendors. These contracts generally
provide for termination on notice and, therefore, are cancellable contracts and not considered contractual obligations and commitments.
Contingencies

From time to time, the Company may become involved in litigation matters arising in the ordinary course of business. The Company is not a party to any material legal proceedings, nor is it aware of any material pending or threatened litigation. There were no contingent liabilities as of June 30, 2026.
v3.26.1
Segment Information
 6 Months Ended
Jun. 30, 2026
Segment Reporting [Abstract]  
Segment Information Segment Information
The Company’s chief operating decision maker (“CODM”) has been identified as the Chief Executive Officer. The Company’s CODM reviews consolidated results to assess performance, makes decisions, and allocates operating and capital resources of the Company as a whole, therefore, there is only one operating and reportable segment. The CODM does not distinguish its principal business activities for the purpose of internal reporting and uses net loss to allocate resources in the annual budgeting and forecasting process, along with using that measure as a basis for evaluating financial performance quarterly by comparing the actual results with historical budgets.

Significant segment expenses that are provided to CODM on a regular basis and are included within reported measure of segment profit or loss are research and development and general and administrative. Other segment items are interest and dividend income and income taxes.
The condensed consolidated statements of operations for the three and six months ended June 30, 2026 and 2025, reflect the significant segment expenses and other segment items, as well as the condensed consolidated balance sheets as of June 30, 2026 and December 31, 2025, for the one reportable segment.
v3.26.1
Related Party Transactions
 6 Months Ended
Jun. 30, 2026
Related Party Transactions [Abstract]  
Related Party Transactions Related Party Transactions
On June 25, 2025, the Company entered into an agreement under which M. Klein & Company, through its affiliate, The Klein Group LLC, will provide financial advisory and strategic services. Mr. Michael Klein, who currently serves as a director of the Company, maintains a direct controlling interest in M. Klein & Company. The advisory agreement is for a term of one year and requires the Company to pay a $250 quarterly retainer fee, in addition to other potential fees depending on the outcomes of certain transactions. During the six months ended June 30, 2026, the Company made total payments of $502 under the agreement.
v3.26.1
Subsequent Events
 6 Months Ended
Jun. 30, 2026
Subsequent Events [Abstract]  
Subsequent Events Subsequent Events
The Company performed an evaluation of subsequent events through the date of filing of these unaudited condensed consolidated financial statements with the SEC and determined that there have been no material subsequent events which affected, or could affect, the amounts or disclosures on the unaudited condensed consolidated financial statements.
v3.26.1
Insider Trading Arrangements
 3 Months Ended
Jun. 30, 2026
shares
Trading Arrangements, by Individual  
Non-Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Terminated false
William Goodwin [Member]  
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
On April 2, 2026, William Goodwin, the Company’s Chief Legal and Strategy Officer, materially modified the Rule 10b5-1 trading arrangement previously adopted by him on December 15, 2025 and previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (the “Prior Trading Arrangement”). The Prior Trading Arrangement was intended to provide for “eligible sell-to-cover transactions” (as described in Rule 10b5-1(c)(1)(ii)(D)(3) under the Exchange Act) to satisfy tax withholding obligations arising exclusively from the vesting of equity awards and the related issuance of up to 13,620 shares of the Company’s common stock, and was scheduled to terminate on December 4, 2026, subject to early termination for certain specified events set forth therein.

For purposes of Rule 10b5-1(c) under the Exchange Act, the April 2, 2026 modification constituted a termination of the Prior Trading Arrangement and the adoption of a new Rule 10b5-1 trading arrangement (the “Modified Trading Arrangement”) intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. The Modified Trading Arrangement provided for the sale of up to 79,677 shares of the Company’s common stock and was scheduled to terminate on December 4, 2026, subject to early termination for certain specified events set forth therein. On June 29, 2026, Mr. Goodwin terminated the Modified Trading Arrangement.
William Goodwin, April 2026 Plan [Member] | William Goodwin [Member]  
Trading Arrangements, by Individual  
Name William Goodwin
Title Chief Legal and Strategy Officer
Rule 10b5-1 Arrangement Adopted true
Adoption Date April 2, 2026
Rule 10b5-1 Arrangement Terminated true
Termination Date June 29, 2026
Expiration Date December 4, 2026
Arrangement Duration 246 days
Aggregate Available 79,677
William Goodwin, December 2025 Plan [Member] | William Goodwin [Member]  
Trading Arrangements, by Individual  
Name William Goodwin
Title Chief Legal and Strategy Officer
Non-Rule 10b5-1 Arrangement Terminated true
Termination Date April 2, 2026
Aggregate Available 13,620
v3.26.1
Summary of Significant Accounting Policies (Policies)
 6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]  
Basis of Presentation
Basis of Presentation

The accompanying unaudited condensed consolidated financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial reporting.

The accompanying unaudited condensed consolidated financial statements and footnote disclosures have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information or footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted, pursuant to the rules and regulations of the SEC for interim financial reporting. Accordingly, they do not include all the information and footnotes necessary for a complete presentation of financial position, results of operations, or cash flows. The information herein should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was filed on March 17, 2026. In the opinion of management, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting of a normal recurring nature, which are necessary for a fair statement of the financial position, operating results, and cash flows for the periods presented.
Restricted Cash
Restricted Cash
Restricted cash consists of cash balances that are subject to restrictions on withdrawal or use. Such amounts are not available for general corporate purposes and may be restricted pursuant to contractual, regulatory, or other arrangements.
Accounts Receivable
Accounts Receivable

Accounts receivable are recorded at the invoiced amount and include amounts earned but not yet billed to customers, net of expected credit losses. The Company estimates expected credit losses based on historical experience and current conditions. The allowance for credit losses was not material as of June 30, 2026 and December 31, 2025.
Revenue Recognition
Revenue Recognition

The Company recognizes revenue in a manner to depict the transfer of goods or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for goods or services. Revenue is recognized when control of the promised good or service is transferred to the customer. Depending on the terms of the arrangement, revenue may be recognized either over time or at a point in time.

During the three and six months ended June 30, 2026, the Company generated revenue primarily from engineering and consulting services, manufacturing and fabrication services, and other ancillary service arrangements. For revenue recognized over time, the Company utilizes input methods based on the expected remaining output of the contract to recognize revenue. The Company determined this is the most faithful depiction of the transfer of goods or services as it is based on the expected remaining effort to deliver under the contracts.

For certain milestone-based contracts, individual contractual deliverables or milestones may represent distinct performance obligations. Revenue associated with these arrangements is generally recognized at a point in time when control of the related good or service transfers to the customer, which may occur upon delivery, customer acceptance, or satisfaction of other contractual criteria.
Contract Balances

Contract assets arise when revenue is recognized before the Company obtains an unconditional right to consideration and generally result from revenue recognized in advance of customer billings. Contract liabilities represent customer prepayments received in advance of satisfying related performance obligations and are recognized as revenue as the Company fulfills those obligations.
Contract assets are included within prepaid expenses and other current assets on the condensed consolidated balance sheets. Contract liabilities are included within other current liabilities on the condensed consolidated balance sheets.
The changes in contract assets and contract liabilities during the period ended June 30, 2026, were primarily attributable to the Company's acquisitions. For additional information about the acquisitions, see Note 3—Business Combinations—2026 Acquisitions.

The Company has elected not to disclose information about remaining performance obligations for (i) contracts with an original expected duration of one year or less and (ii) contracts for which revenue is recognized using the right-to-invoice practical expedient, whereby the amount invoiced corresponds directly with the value of the Company's performance completed to date. As of June 30, 2026, remaining performance obligations not subject to these exceptions were not material.
Cost of Sales
Cost of Sales

Cost of sales includes direct costs incurred in satisfying performance obligations under customer contracts.
Segment Information
Segment Information
The Company has viewed its financial information on an aggregate basis for the purposes of evaluating financial performance and allocating the Company’s resources. The Company’s principal business consists primarily of research and development and deployment activities for its planned or in-process powerhouses, nuclear fuel recycling and fuel fabrication facilities, and its radioisotope production facilities. Accordingly, the Company has determined that it conducts its business in one operating and reportable segment.
Principles of Consolidation
Principles of Consolidation

The unaudited condensed consolidated financial statements include the Company’s accounts and those of its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated.
Use of Estimates
Use of Estimates
Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, judgments, and assumptions that affect the amounts reported and disclosed in the unaudited condensed consolidated financial statements and accompanying notes. Actual results could differ materially from these estimates. On an ongoing basis, the Company evaluates its estimates, including those related to the valuation of operating lease liabilities and operating right-of-use assets, useful lives of property, plant and equipment, valuation allowance on deferred tax assets, and the fair value of acquired intangible assets and goodwill. These estimates, judgments, and assumptions are based on current and expected economic conditions, historical data, and experience available at the date of the accompanying unaudited condensed consolidated financial statements, and various other factors that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Risk and Uncertainties
Risk and Uncertainties

The Company is subject to continuing risks and uncertainties amidst a range of supply chain, construction, and design complexities and in connection with the market dynamics around fuel costs and the current macroeconomic environment, including as a result of inflation, instability in the global banking system, trade policy (including tariffs, export controls, and sanctions), ongoing or escalating geopolitical factors and military activities, as well as the potential for additional conflicts, war or civil unrest. At this point, the extent to which these effects may impact the Company’s future financial condition or results of operations is uncertain, and as of the date of issuance of these unaudited condensed consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the update of any estimates or judgments or an adjustment of the carrying value of any assets or liabilities. These estimates may change as new events occur and additional information is obtained and will be recognized in the financial statements as soon as they become known.
Net Loss Per Common Share
Net Loss Per Common Share

The Company’s basic net loss per share of common stock is computed based on the average number of outstanding shares of common stock for the period, by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss per share of common
stock is computed by dividing net loss by the weighted-average number of shares of common stock and common share equivalents of potentially dilutive securities outstanding for the period. Potentially dilutive securities include common stock equivalents. Since the Company was in a loss position for the periods presented, basic net loss per share of common stock is the same as diluted net loss per share of common stock since the effects of potentially dilutive securities are antidilutive.
Recently Issued and Not Adopted Accounting Standards
Recently Issued and Not Adopted Accounting Standards

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which will require disaggregated disclosures in the notes to the financial statements of certain categories of expenses, including purchases of inventory, employee compensation, and depreciation and amortization, that are included in expense line items within the statement of operations. ASU 2024-03 will be applied prospectively; however, retrospective application is permitted. ASU 2024-03, as clarified in ASU 2025-01, Clarifying the Effective Date, is effective for the Company's annual reporting period ending December 31, 2027. Early adoption is permitted. The Company is evaluating the impact of ASU 2024-03 on its disclosures in the notes to its financial statements.

In September 2025, the FASB issued ASU 2025‑06, Intangibles—Goodwill and Other—Internal‑Use Software (Subtopic 350‑40): Targeted Improvements to the Accounting for Internal‑Use Software, which updates the guidance for capitalization of internal‑use software costs, including clarifications to the criteria for capitalizing configuration, development, and implementation activities. ASU 2025-06 is effective for the Company beginning with interim reporting for fiscal year 2029. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2025-06 on its accounting policies and related disclosures.

In December 2025, the FASB issued ASU 2025‑10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which provides updated guidance on how to recognize, measure, and present government grants. ASU 2025‑10 is effective for the Company for annual periods beginning after December 15, 2028, including interim periods within those periods using a modified prospective, modified retrospective, or full retrospective transition approach. Early adoption is permitted. The Company is currently assessing the effect of ASU 2025-10 on its financial statements.
v3.26.1
Summary of Significant Accounting Policies (Tables)
 6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]  
Schedule of Disaggregation of Revenue
The following table presents revenue disaggregated by nature of revenue stream for the periods presented:
Three and Six Months Ended June 30,
20262025
Engineering and consulting services
$800 $— 
Manufacturing and fabrication services
168 — 
Other
242 — 
Total revenue recognized
$1,210 $— 
Schedule of Contract Balances
The following table presents contract balances for the periods presented:
As of
June 30, 2026
(unaudited)		December 31, 2025
Contract assets
$2,402 $— 
Contract liabilities
53 — 
v3.26.1
Business Combinations (Tables)
 6 Months Ended
Jun. 30, 2026
Business Combination [Abstract]  
Schedule of Business Acquisitions, by Acquisition
The composition of the preliminary purchase price is as follows:
Cash$26,768 
Purchase price holdback amounts, net4,066 
Contingent consideration3,110 
Settlement of preexisting relationships(564)
Total purchase consideration$33,380 
The composition of the purchase price is as follows:
Cash$1,016 
Common stock27,408 
Total purchase consideration$28,424 
Schedule of Assets Acquired and Liabilities Assumed
The preliminary purchase price allocation resulted in the following amounts being allocated to the assets acquired and liabilities assumed at the acquisition dates based upon their respective fair values as summarized below:
Cash$1,032 
Accounts receivable2,496 
Prepaid expenses and other current assets2,437 
Property, plant and equipment3,966 
Operating lease right-of-use assets320 
Intangible assets16,800 
Goodwill9,914 
Accounts payable(205)
Accrued expenses and other(716)
Other current liabilities(102)
Operating lease liability(320)
Debt(2,242)
Net assets acquired$33,380 
The purchase price allocation resulted in the following amounts being allocated to the assets acquired and liabilities assumed at the Acquisition Date based upon their respective fair values as summarized below:
Cash$116 
Prepaid expenses99 
Property and equipment40 
Operating lease right-of-use assets19 
Indefinite-lived intangible assets27,500 
Goodwill6,621 
Operating lease liability(19)
Other current liabilities(268)
Deferred tax liabilities(5,684)
Net assets acquired
$28,424 
v3.26.1
Balance Sheet Components (Tables)
 6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Schedule of Prepaid Expenses and Other Current Assets
Prepaid expenses and other current assets are summarized as follows:
As of
June 30, 2026
(unaudited)		December 31, 2025
Prepaid expenses$15,079 $18,853 
Accrued interest receivable10,273 4,976 
Other20,020 1,969 
Total prepaid expenses and other current assets$45,372 $25,798 
Schedule of Property, Plant and Equipment, Net
Property, plant and equipment, net are summarized as follows:
As of
Estimates Useful Lives (Years)June 30, 2026
(unaudited)		December 31, 2025
Computers and equipment
3 - 7
$740 $366 
Furniture, fixtures and machinery72,796 483 
Software31,405 1,405 
Leasehold improvements*255 62 
Land and buildings407,182 5,145 
Total property, plant and equipment, gross12,378 7,461 
Less: accumulated depreciation and amortization(1,300)(897)
Construction in progress and equipment deposits165,117 35,748 
Total property, plant and equipment, net$176,195 $42,312 
* Shorter of lease term or estimated useful life of the asset.
Schedule of Intangible Assets
Intangible assets are summarized as follows:

As of
Estimated Useful Lives (Years)June 30, 2026
(unaudited)		December 31, 2025
IPR&DN/A$27,500 $27,500 
Customer relationships10.916,000 — 
Trade names8.5800 — 
Total intangible assets44,300 27,500 
Less: accumulated amortization(97)— 
Total intangible assets, net$44,203 $27,500 
Schedule of Intangible Assets
Intangible assets are summarized as follows:

As of
Estimated Useful Lives (Years)June 30, 2026
(unaudited)		December 31, 2025
IPR&DN/A$27,500 $27,500 
Customer relationships10.916,000 — 
Trade names8.5800 — 
Total intangible assets44,300 27,500 
Less: accumulated amortization(97)— 
Total intangible assets, net$44,203 $27,500 
Schedule of Other Assets
Other assets are summarized as follows:
As of
June 30, 2026
(unaudited)		December 31, 2025
Finance lease right-of-use asset$933 $— 
Prepayments17,730217 
Other investments28,586 12,086 
Total other assets$47,249 $12,303 
Schedule of Accrued Expenses and Other
Accrued expenses and other are summarized as follows:
As of
June 30, 2026
(unaudited)		December 31, 2025
Accrued professional fees$2,689 $1,838 
Accrued payroll and bonuses11,160 10,998 
General accrued expenses20,754 7,210 
Contingent consideration1,880 — 
Other1,540 451 
Total accrued expenses and other$38,023 $20,497 
v3.26.1
Leases (Tables)
 6 Months Ended
Jun. 30, 2026
Leases [Abstract]  
Schedule of Lease Supplemental Information and Lease Cost
The table below presents supplemental information related to the operating and finance leases:
Six Months Ended June 30,
20262025
Cash payments included in the measurement of operating lease liabilities during the period$637 $376 
Cash payments included in the measurement of finance lease liability during the period750 — 
Operating lease liabilities arising from obtaining lease right-of-use assets during the period2,016 1,142 
Finance lease liability arising from obtaining lease right-of-use asset during the period933 — 

Weighted average remaining lease terms and weighted average discount rates were as follows as of June 30, 2026:
Operating LeasesFinance Lease
Weighted-average remaining lease term (in years) as of period-end
3.414.8
Weighted-average discount rate during the period8.94%9.50%
The components of operating and finance lease costs were as follows:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Operating lease costs included in:
Research and development$1,486 $212 $1,746 $363 
General and administrative742 106 847 186 
Total operating costs (1)
2,228 318 2,593 549 
Finance lease cost:
Interest on lease liabilities4 — 4 — 
Total lease cost$2,232 $318 $2,597 $549 

(1) Month-to-month lease arrangements for the three months ended June 30, 2026 and 2025 of $1,865 and $80, respectively, and six months ended June 30, 2026 and 2025 of $1,922 and $151, respectively, are included in the captions within operating lease costs.
Schedule of Operating Lease Maturities
As of June 30, 2026, future maturities of the operating and finance lease liabilities were as follows:
Operating Leases
Finance Lease
2026 (remaining of year)$801 $— 
2027901 — 
2028910 — 
2029793 — 
2030270 — 
Thereafter125 750 
Minimum lease payments3,800 750 
Less imputed interest(541)(563)
Present value of lease liabilities$3,259 $187 
Current portion of lease liabilities$1,025 $— 
Noncurrent portion of lease liabilities2,234 187 
Total lease liabilities$3,259 $187 
Schedule of Finance Lease Maturities
As of June 30, 2026, future maturities of the operating and finance lease liabilities were as follows:
Operating Leases
Finance Lease
2026 (remaining of year)$801 $— 
2027901 — 
2028910 — 
2029793 — 
2030270 — 
Thereafter125 750 
Minimum lease payments3,800 750 
Less imputed interest(541)(563)
Present value of lease liabilities$3,259 $187 
Current portion of lease liabilities$1,025 $— 
Noncurrent portion of lease liabilities2,234 187 
Total lease liabilities$3,259 $187 
v3.26.1
Financial Instruments (Tables)
 6 Months Ended
Jun. 30, 2026
Investments, Debt and Equity Securities [Abstract]  
Schedule of Cash, Cash Equivalents and Marketable Debt Securities by Significant Investment Category
The following table shows the Company’s cash, cash equivalents and marketable debt securities by significant investment category:
As of June 30, 2026
Amortized CostUnrealized Gains
Unrealized Losses (1)
Fair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $— $57,623 $— $— 
Level 1:
Money market funds— — — — 1,571,094 — — 
U.S. Treasury securities1,244,182 61 (4,041)1,240,202 — 699,071 541,131 
Subtotal1,244,182 61 (4,041)1,240,202 1,571,094 699,071 541,131 
Level 2 (2):
Commercial paper137,423 — (53)137,370 15,987 121,383 — 
Total $1,381,605 $61 $(4,094)$1,377,572 $1,644,704 $820,454 $541,131 

(1) There was no allowance for expected credit losses on available-for-sale marketable debt securities as of June 30, 2026 as the unrealized losses were deemed to be temporary in nature.

(2) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.
The following tables show the Company’s cash, cash equivalents, and marketable debt securities by significant investment category:
As of December 31, 2025
Amortized CostUnrealized GainsFair ValueCash and Cash EquivalentsCurrent Marketable Debt SecuritiesNoncurrent Marketable Debt Securities
Cash$— $— $— $11,022 $— $— 
Level 1:
Money market funds— — — 777,423 — — 
U.S. Treasury securities504,008 1,123 505,131 — 320,563 184,568 
Subtotal504,008 1,123 505,131 777,423 320,563 184,568 
Level 2 (1):
Commercial paper118,907 56 118,963 — 118,963 — 
Total$622,915 $1,179 $624,094 $788,445 $439,526 $184,568 

(1) The valuation techniques used to measure the fair values of the Company’s Level 2 financial instruments, which generally have counterparties with high credit ratings, are based on quoted market prices or model-driven valuations using significant inputs derived from or corroborated by observable market data.
Schedule of Fair Value of the Company’s Marketable Debt Securities, by Contractual Maturity
The following table shows the fair value of the Company’s noncurrent marketable debt securities, by contractual maturity, as of June 30, 2026:

Due within 1 year$820,454 
Due after 1 year through 5 years541,131 
Total fair value$1,361,585 
Schedule of Fair Value of Contingent Consideration
The following table presents the fair value of the Company's contingent consideration measured on a recurring basis as of June 30, 2026:

Fair ValueQuoted Prices in Active Markets for Identical Assets (Level 1)Significant Other Observable Inputs (Level 2)Significant Unobservable Inputs (Level 3)
Contingent consideration$3,110 $— $— $3,110 
v3.26.1
Stockholders’ Equity (Tables)
 6 Months Ended
Jun. 30, 2026
Equity [Abstract]  
Schedule of Shares Issued
The following is a summary of the shares issued under the ATM Programs during the six months ended June 30, 2026 (in thousands except shares issued and average price per share):
ATM ProgramsShares IssuedAverage Net Price Per ShareGross ProceedsNet Proceeds
2025 ATM Program12,376,352$96.95$1,199,868 $1,181,897 
2026 ATM Program10,712,054$63.51680,371 670,047 
Total / Average23,088,406$81.44$1,880,239 $1,851,944 
v3.26.1
Stock-Based Compensation (Tables)
 6 Months Ended
Jun. 30, 2026
Share-Based Payment Arrangement [Abstract]  
Schedule of Stock-Based Compensation Expense
The Company recorded stock-based compensation in the following expense categories in its condensed consolidated statement of operations for employees and non-employees:

Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Research and development$5,603 $3,229 $13,099 $4,202 
General and administrative8,755 8,136 16,845 9,474 
Total costs charged to operations$14,358 $11,365 $29,944 $13,676 
Schedule of Unrecognized Compensation Expense
Unrecognized compensation costs and expected weighted-average period to be recognized related to the stock-based compensation awards as of June 30, 2026 were as follows:

Restricted StockStock OptionsTotals
Unrecognized stock-based compensation cost$172,870 $12,618 $185,488 
Weighted-average period over which cost is expected to be recognized (in years)3.753.093.70
v3.26.1
Nature of Operations and Organization (Details)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
MWd
Mar. 31, 2026
USD ($)
Jun. 30, 2025
USD ($)
Mar. 31, 2025
USD ($)
Jun. 30, 2026
USD ($)
MWd
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]              
Powerhouse production capability, nuclear fuel | MWd 15       15    
Powerhouse production capability, fresh fuel | MWd 75       75    
Powerhouse useful life 30 years       30 years    
Cash, cash equivalents, and marketable securities $ 3,006,289       $ 3,006,289    
Net loss 48,536 $ 33,065 $ 24,685 $ 9,810 81,601 $ 34,495  
Operating loss 73,190   $ 28,015   124,166 45,889  
Net cash used in operating activities         65,459 $ 30,714  
Accumulated deficit $ 322,373       $ 322,373   $ 240,772
v3.26.1
Summary of Significant Accounting Policies - Schedule of Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Property, Plant and Equipment [Line Items]    
Total revenue recognized $ 1,210 $ 0
Engineering and consulting services    
Property, Plant and Equipment [Line Items]    
Total revenue recognized 800 0
Manufacturing and fabrication services    
Property, Plant and Equipment [Line Items]    
Total revenue recognized 168 0
Other    
Property, Plant and Equipment [Line Items]    
Total revenue recognized $ 242 $ 0
v3.26.1
Summary of Significant Accounting Policies - Schedule of Contract Balances (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Accounting Policies [Abstract]    
Contract assets $ 2,402 $ 0
Contract liabilities $ 53 $ 0
v3.26.1
Summary of Significant Accounting Policies (Details)
 6 Months Ended 12 Months Ended
Jun. 30, 2026
segment
shares
Jun. 30, 2025
shares
Dec. 31, 2025
segment
Property, Plant and Equipment [Line Items]      
Number of operating segments | segment 1   1
Number of reportable segments | segment 1   1
Stock Options      
Property, Plant and Equipment [Line Items]      
Antidilutive securities excluded from earnings per share (in shares) 5,738,353 8,430,096  
Restricted Stock      
Property, Plant and Equipment [Line Items]      
Antidilutive securities excluded from earnings per share (in shares) 373,406 640,125  
Restricted Stock Units      
Property, Plant and Equipment [Line Items]      
Antidilutive securities excluded from earnings per share (in shares) 3,525,985 2,337,546  
v3.26.1
Business Combinations - Narrative (Details)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 15, 2026
USD ($)
Jun. 15, 2026
USD ($)
Jun. 04, 2026
USD ($)
Feb. 28, 2025
USD ($)
project
$ / shares
shares
Jun. 30, 2026
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Business Combination [Line Items]                
Payment for acquisition of businesses, net of cash acquired           $ 25,736,000 $ 900,000  
Purchase price adjustments or indemnification claims         $ 3,110,000 3,110,000    
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc.                
Business Combination [Line Items]                
Total purchase consideration $ 33,380,000              
Transaction costs $ 575,000              
Revenue of acquiree since acquisition date         968,000 968,000    
Loss from operations since acquisition date         $ 42,000 $ 42,000    
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc. | Customer Relationships                
Business Combination [Line Items]                
Weighted average useful life 10 years 10 months 24 days              
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc. | Trade Names                
Business Combination [Line Items]                
Weighted average useful life 8 years 6 months              
ARMEC, LLC and Precision Manufacturing & Engineering Solutions, LLC                
Business Combination [Line Items]                
Total purchase consideration     $ 20,462,000          
Payment for acquisition of businesses, net of cash acquired     15,857,000          
Potential maximum contingent consideration payment     5,000,000          
ARMEC, LLC and Precision Manufacturing & Engineering Solutions, LLC | Purchase Price Holdback Amounts                
Business Combination [Line Items]                
Purchase price adjustments or indemnification claims     1,700,000          
ARMEC, LLC and Precision Manufacturing & Engineering Solutions, LLC | Earnout Contingent Consideration                
Business Combination [Line Items]                
Purchase price adjustments or indemnification claims     $ 3,110,000          
Creative Engineers, Inc                
Business Combination [Line Items]                
Total purchase consideration   $ 12,918,000            
Payment for acquisition of businesses, net of cash acquired   10,911,000            
Purchase price adjustments or indemnification claims $ 2,000,000 $ 2,000,000            
Atomic Alchemy, Inc.                
Business Combination [Line Items]                
Total purchase consideration       $ 28,424,000        
Payment for acquisition of businesses, net of cash acquired       900,000        
Transaction costs       $ 410,000        
Share price (in dollars per share) | $ / shares       $ 33.39        
Common stock       $ 27,408,000        
Decrease in deferred tax liabilities               $ 99,000
IPR&D projects, number | project       2        
Indefinite-lived intangible assets       $ 27,500,000        
Tax-deductible goodwill       0        
Atomic Alchemy, Inc. | In Process Research and Development, Abundantia Project                
Business Combination [Line Items]                
Indefinite-lived intangible assets       4,600,000        
Atomic Alchemy, Inc. | In Process Research and Development, Meitner Project                
Business Combination [Line Items]                
Indefinite-lived intangible assets       $ 22,900,000        
Atomic Alchemy, Inc. | Class A common stock, stock purchase consideration                
Business Combination [Line Items]                
Equity interests issued or issuable (in shares) | shares       820,840        
Atomic Alchemy, Inc. | Class A common stock, post combination services consideration                
Business Combination [Line Items]                
Equity interests issued or issuable (in shares) | shares       274,339        
v3.26.1
Business Combinations - Schedule of Purchase Price (Details) - USD ($)
Jun. 15, 2026
Feb. 28, 2025
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc.    
Business Combination [Line Items]    
Cash $ 26,768,000  
Settlement of preexisting relationships (564,000)  
Total purchase consideration 33,380,000  
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc. | Purchase Price Holdback Amounts    
Business Combination [Line Items]    
Purchase price holdback amounts, net and contingent consideration 4,066,000  
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc. | Earnout Contingent Consideration    
Business Combination [Line Items]    
Purchase price holdback amounts, net and contingent consideration $ 3,110,000  
Atomic Alchemy, Inc.    
Business Combination [Line Items]    
Cash   $ 1,016,000
Common stock   27,408,000
Total purchase consideration   $ 28,424,000
v3.26.1
Business Combinations - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Jun. 15, 2026
Dec. 31, 2025
Feb. 28, 2025
Business Combination [Line Items]        
Goodwill $ 16,535   $ 6,621  
ARMEC, LLC And Precision Manufacturing & Engineering Solutions, LLC and Creative Engineers, Inc.        
Business Combination [Line Items]        
Cash   $ 1,032    
Accounts receivable   2,496    
Prepaid expenses and other current assets   2,437    
Property, plant and equipment   3,966    
Operating lease right-of-use assets   320    
Intangible assets   16,800    
Goodwill   9,914    
Accounts payable   (205)    
Accrued expenses and other   (716)    
Other current liabilities   (102)    
Operating lease liability   (320)    
Debt   (2,242)    
Net assets acquired   $ 33,380    
Atomic Alchemy, Inc.        
Business Combination [Line Items]        
Cash       $ 116
Prepaid expenses       99
Property, plant and equipment       40
Operating lease right-of-use assets       19
Indefinite-lived intangible assets       27,500
Goodwill       6,621
Other current liabilities       (268)
Operating lease liability       (19)
Deferred tax liabilities       (5,684)
Net assets acquired       $ 28,424
v3.26.1
Balance Sheet Components - Schedule of Prepaid Expense and Other Current Assets (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Prepaid expenses $ 15,079 $ 18,853
Accrued interest receivable 10,273 4,976
Other 20,020 1,969
Total prepaid expenses and other current assets $ 45,372 $ 25,798
v3.26.1
Balance Sheet Components - Schedule of Property, Plant and Equipment, Net (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Property, Plant, and Equipment [Line Items]    
Total property, plant and equipment, gross $ 12,378 $ 7,461
Less: accumulated depreciation and amortization (1,300) (897)
Construction in progress and equipment deposits 165,117 35,748
Total property, plant and equipment, net 176,195 42,312
Computers and equipment    
Property, Plant, and Equipment [Line Items]    
Total property, plant and equipment, gross $ 740 366
Computers and equipment | Minimum    
Property, Plant, and Equipment [Line Items]    
Estimates Useful Lives (Years) 3 years  
Computers and equipment | Maximum    
Property, Plant, and Equipment [Line Items]    
Estimates Useful Lives (Years) 7 years  
Furniture, fixtures and machinery    
Property, Plant, and Equipment [Line Items]    
Estimates Useful Lives (Years) 7 years  
Total property, plant and equipment, gross $ 2,796 483
Software    
Property, Plant, and Equipment [Line Items]    
Estimates Useful Lives (Years) 3 years  
Total property, plant and equipment, gross $ 1,405 1,405
Leasehold improvements    
Property, Plant, and Equipment [Line Items]    
Total property, plant and equipment, gross $ 255 62
Land and Building    
Property, Plant, and Equipment [Line Items]    
Estimates Useful Lives (Years) 40 years  
Total property, plant and equipment, gross $ 7,182 $ 5,145
v3.26.1
Balance Sheet Components - Narrative (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Property, Plant, and Equipment [Line Items]        
Depreciation and amortization     $ 500,000 $ 249,000
Amortization expense $ 97,000 $ 0 97,000 0
Property, Plant and Equipment        
Property, Plant, and Equipment [Line Items]        
Depreciation and amortization $ 240,000 $ 125,000 $ 403,000 $ 249,000
v3.26.1
Balance Sheet Components - Schedule of Intangible Assets (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Intangible Asset, Finite-Lived [Line Items]    
Intangible assets, net $ 27,500 $ 27,500
Total intangible assets 44,300 27,500
Less: accumulated amortization (97) 0
Total intangible assets, net $ 44,203 27,500
Customer Relationships    
Intangible Asset, Finite-Lived [Line Items]    
Estimated Useful Lives (Years) 10 years 10 months 24 days  
Net carrying value $ 16,000 0
Trade Names    
Intangible Asset, Finite-Lived [Line Items]    
Estimated Useful Lives (Years) 8 years 6 months  
Net carrying value $ 800 $ 0
v3.26.1
Balance Sheet Components - Schedule of Other Assets (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Finance lease right-of-use asset $ 933 $ 0
Prepayments 17,730 217
Other investments 28,586 12,086
Total other assets $ 47,249 $ 12,303
v3.26.1
Balance Sheet Components - Schedule of Accrued Expenses and Other (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Accrued professional fees $ 2,689 $ 1,838
Accrued payroll and bonuses 11,160 10,998
General accrued expenses 20,754 7,210
Contingent consideration 1,880 0
Other 1,540 451
Total accrued expenses and other $ 38,023 $ 20,497
v3.26.1
Leases - Schedule of Supplemental Information (Details) - USD ($)
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Leases [Abstract]    
Cash payments included in the measurement of operating lease liabilities during the period $ 637,000 $ 376,000
Cash payments included in the measurement of finance lease liability during the period 750,000 0
Operating lease liabilities arising from obtaining lease right-of-use assets during the period 2,016,000 1,142,000
Finance lease liability arising from obtaining lease right-of-use asset during the period $ 933,000 $ 0
Operating lease, weighted-average remaining lease term (in months) as of period-end 3 years 4 months 24 days  
Operating lease, weighted-average discount rate during the period 8.94%  
Finance lease, Weighted-average remaining lease term (in months) as of period-end 14 years 9 months 18 days  
Finance lease, weighted-average discount rate during the period 9.50%  
v3.26.1
Leases - Narratives (Details)
$ in Thousands
Jun. 30, 2026
USD ($)
Leases [Abstract]  
Finance lease liabilities $ 187
v3.26.1
Leases - Schedule of Operating and Finance Lease Costs (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Lessee, Lease, Description [Line Items]        
Total operating costs $ 2,228 $ 318 $ 2,593 $ 549
Interest on lease liabilities 4 0 4 0
Total lease cost 2,232 318 2,597 549
Month-to-Month Lease Arrangements        
Lessee, Lease, Description [Line Items]        
Total operating costs 1,865 80 1,922 151
Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense        
Lessee, Lease, Description [Line Items]        
Total operating costs 742 106 847 186
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense        
Lessee, Lease, Description [Line Items]        
Total operating costs $ 1,486 $ 212 $ 1,746 $ 363
v3.26.1
Leases - Schedule of Operating and Finance Lease Maturities (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Operating Leases    
2026 (remaining of year) $ 801  
2027 901  
2028 910  
2029 793  
2030 270  
Thereafter 125  
Minimum lease payments 3,800  
Less imputed interest (541)  
Current portion of lease liabilities 1,025 $ 904
Noncurrent portion of lease liabilities 2,234 $ 546
Operating lease liability, total 3,259  
Finance Lease    
2026 (remaining of year) 0  
2027 0  
2028 0  
2029 0  
2030 0  
Thereafter 750  
Minimum lease payments 750  
Less imputed interest (563)  
Current portion of lease liabilities 0  
Noncurrent portion of lease liabilities 187  
Finance lease liability, total $ 187  
v3.26.1
Financial Instruments - Schedule of Cash, Cash Equivalents, and Marketable Debt Securities by Investment Category (Details) - USD ($)
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Cash $ 57,623,000 $ 11,022,000  
Amortized Cost 1,381,605,000 622,915,000  
Unrealized Gains 61,000 1,179,000  
Unrealized Losses (4,094,000)    
Fair Value 1,377,572,000 624,094,000  
Cash and Cash Equivalents 1,644,704,000 788,445,000 $ 226,771,000
Current Marketable Debt Securities 820,454,000 439,526,000  
Noncurrent Marketable Debt Securities 541,131,000 184,568,000  
Allowance for credit loss 0    
Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost 1,244,182,000 504,008,000  
Unrealized Gains 61,000 1,123,000  
Unrealized Losses (4,041,000)    
Fair Value 1,240,202,000 505,131,000  
Cash and Cash Equivalents 1,571,094,000 777,423,000  
Current Marketable Debt Securities 699,071,000 320,563,000  
Noncurrent Marketable Debt Securities 541,131,000 184,568,000  
Level 1 | U.S. Treasury securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost 1,244,182,000 504,008,000  
Unrealized Gains 61,000 1,123,000  
Unrealized Losses (4,041,000)    
Fair Value 1,240,202,000 505,131,000  
Current Marketable Debt Securities 699,071,000 320,563,000  
Noncurrent Marketable Debt Securities 541,131,000 184,568,000  
Level 1 | Money market funds      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Cash and Cash Equivalents 1,571,094,000 777,423,000  
Level 2 | Commercial paper      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost 137,423,000 118,907,000  
Unrealized Gains 0 56,000  
Unrealized Losses (53,000)    
Fair Value 137,370,000 118,963,000  
Cash and Cash Equivalents 15,987,000    
Current Marketable Debt Securities $ 121,383,000 $ 118,963,000  
v3.26.1
Financial Instruments - Narrative (Details) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]    
Contingent consideration period 2 years  
Purchase price adjustments or indemnification claims $ 3,110  
Location, Statement of Financial Position, Balance [Axis]: us-gaap:AccruedLiabilitiesCurrent    
Debt Securities, Available-for-Sale [Line Items]    
Purchase price adjustments or indemnification claims 1,880  
Location, Statement of Financial Position, Balance [Axis]: us-gaap:DebtSecuritiesAvailableForSaleExcludingAccruedInterestCurrent    
Debt Securities, Available-for-Sale [Line Items]    
Debt securities interest receivable $ 4,896 $ 4,005
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Marketable debt securities Marketable debt securities
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Debt Securities, Available-for-Sale [Line Items]    
Purchase price adjustments or indemnification claims $ 1,230  
Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Debt Securities, Available-for-Sale [Line Items]    
Debt securities interest receivable $ 6,769 $ 3,160
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Prepaid expenses and other current assets Prepaid expenses and other current assets
v3.26.1
Financial Instruments - Schedule of Fair Value of the Company’s Marketable Debt Securities, by Contractual Maturity (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]    
Fair Value $ 1,377,572 $ 624,094
Commercial Paper, Not Included with Cash and Cash Equivalents    
Debt Securities, Available-for-Sale [Line Items]    
Due within 1 year 820,454  
Due after 1 year through 5 years 541,131  
Fair Value $ 1,361,585  
v3.26.1
Financial Instruments - Schedule of Fair Value of Contingent Consideration (Details)
$ in Thousands
Jun. 30, 2026
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contingent consideration $ 3,110
Level 1  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contingent consideration 0
Level 2  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contingent consideration 0
Level 3  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contingent consideration $ 3,110
v3.26.1
Right of First Refusal Liability (Details) - USD ($)
$ in Thousands
 1 Months Ended
Mar. 31, 2024
Jun. 30, 2026
Dec. 31, 2025
Feb. 16, 2024
Commitments and Contingencies Disclosure [Abstract]        
Commitment period       20 years
Purchase power agreement additional extension term       20 years
Right of first refusal term       36 months
Right of first refusal payment $ 25,000      
Right of first refusal liability   $ 25,000 $ 25,000  
v3.26.1
Stockholders’ Equity - Narrative (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
May 31, 2026
USD ($)
Jun. 30, 2026
USD ($)
$ / shares
shares
Jun. 30, 2025
USD ($)
shares
Jun. 30, 2026
USD ($)
$ / shares
shares
Jun. 30, 2025
USD ($)
shares
Dec. 31, 2025
USD ($)
$ / shares
shares
Class of Stock [Line Items]            
Common stock and preferred stock, authorized (in shares)   501,000,000   501,000,000    
Common stock, authorized (in shares)   500,000,000   500,000,000   500,000,000
Common stock, par value (in dollars per share) | $ / shares   $ 0.0001   $ 0.0001   $ 0.0001
Preferred stock, authorized (in shares)   1,000,000   1,000,000    
Preferred stock, par value (in dollars per share) | $ / shares   $ 0.0001   $ 0.0001    
Issuance of common stock (in shares)   360,704 697,177 651,612 1,016,098  
Issuance of common stock | $   $ 860 $ 628 $ 1,597 $ 1,348  
Common stock withheld for taxes (in shares)       1,280 66,724  
Payment of taxes from common stock withheld | $       $ 75 $ 1,595  
Restricted Stock            
Class of Stock [Line Items]            
Vesting of restricted stock units (in shares)   149,558 42,866 837,314 177,698  
2025 ATM Program            
Class of Stock [Line Items]            
Proceeds from issuance of common stock, gross | $       $ 1,199,868   $ 1,500
Sale of stock, commission percentage           0.015
Issuance of common stock (in shares)       12,376,352    
2026 ATM Program            
Class of Stock [Line Items]            
Proceeds from issuance of common stock, gross | $ $ 1,000     $ 680,371    
Sale of stock, commission percentage 0.015          
Issuance of common stock (in shares)       10,712,054    
v3.26.1
Stockholders’ Equity - Schedule of Shares Issued (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
May 31, 2026
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Class of Stock [Line Items]            
Issuance of stock (in shares)   360,704 697,177 651,612 1,016,098  
Net Proceeds       $ 1,851,944 $ 441,600  
At The Market Offering            
Class of Stock [Line Items]            
Issuance of stock (in shares)       23,088,406    
Average Net Price Per Share (in dollars per share)       $ 81.44    
Gross Proceeds       $ 1,880,239    
Net Proceeds       $ 1,851,944    
2025 ATM Program            
Class of Stock [Line Items]            
Issuance of stock (in shares)       12,376,352    
Average Net Price Per Share (in dollars per share)       $ 96.95    
Gross Proceeds       $ 1,199,868   $ 1,500
Net Proceeds       $ 1,181,897    
2026 ATM Program            
Class of Stock [Line Items]            
Issuance of stock (in shares)       10,712,054    
Average Net Price Per Share (in dollars per share)       $ 63.51    
Gross Proceeds $ 1,000     $ 680,371    
Net Proceeds       $ 670,047    
v3.26.1
Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]        
Share-Based Payment Arrangement, Expense $ 14,358,000 $ 11,365,000 $ 29,944,000 $ 13,676,000
Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense        
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]        
Share-Based Payment Arrangement, Expense 8,755,000 8,136,000 16,845,000 9,474,000
Share-Based Payment Arrangement, Amount Capitalized 37,000 0 37,000 0
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense        
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]        
Share-Based Payment Arrangement, Expense 5,603,000 3,229,000 13,099,000 4,202,000
Share-Based Payment Arrangement, Amount Capitalized $ 713,000 $ 0 $ 713,000 $ 0
v3.26.1
Stock-Based Compensation - Narrative (Details) - Restricted Stock
$ in Thousands
 6 Months Ended
Jun. 30, 2026
USD ($)
shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Granted (in shares) | shares 1,730,000
Issued during period, grant date fair value | $ $ 107,000
v3.26.1
Stock-Based Compensation - Schedule of Unrecognized Compensation Expense (Details)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
USD ($)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Unrecognized stock-based compensation cost $ 185,488
Weighted-average period over which cost is expected to be recognized (in years) 3 years 8 months 12 days
Restricted Stock  
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Unrecognized stock-based compensation cost $ 172,870
Weighted-average period over which cost is expected to be recognized (in years) 3 years 9 months
Stock Options  
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]  
Unrecognized stock-based compensation cost $ 12,618
Weighted-average period over which cost is expected to be recognized (in years) 3 years 1 month 2 days
v3.26.1
Income Taxes (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Income Tax Disclosure [Abstract]        
Income tax (benefit) expense $ (3,153) $ 431 $ 2 $ (3,980)
v3.26.1
Commitments and Contingencies (Details)
Jun. 30, 2026
USD ($)
Commitments and Contingencies Disclosure [Abstract]  
Loss contingency accrual $ 0
v3.26.1
Segment Information (Details) - segment
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Segment Reporting [Abstract]    
Number of reportable segments 1 1
Number of operating segments 1 1
v3.26.1
Related Party Transactions (Details) - Klein Group LLC - USD ($)
$ in Thousands
 6 Months Ended
Jun. 25, 2025
Jun. 30, 2026
Related Party Transaction [Line Items]    
Advisory agreement term 1 year  
Advisory agreement, quarterly retainer fee $ 250  
Advisory agreement, payment of quarterly retainer fee   $ 502