Fair Value Measurements (Tables)

3 Months Ended

12 Months Ended

Mar. 29, 2026

Dec. 28, 2025

Fair Value Measurements [Abstract]

Schedule of Financial Assets and Liabilities that are Measured at Fair Value on a Recurring Basis

The following table sets forth the Company’s financial assets and liabilities that are measured at fair value on a recurring basis (in thousands):

		As of March 29, 2026
		Level 1				Level 2				Level 3				Total
Financial Assets
Restricted cash		$	1,134			$	—			$	—			$	1,134
Total		$	1,134			$	—			$	—			$	1,134
Financial Liabilities
July 2024 Notes derivative liability ⁽¹⁾		$	—			$	—			$	14,042			$	14,042
July 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				9,036				9,036
September 2024 Notes derivative liability ⁽¹⁾			—				—				26,351				26,351
September 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				4,286				4,286
July 2025 Note derivative liability– related party ⁽¹⁾			—				—				2,239				2,239
September 2025 Notes derivative liability ⁽¹⁾			—				—				10,825				10,825
November 2025 Note derivative liability – related party ⁽¹⁾			—				—				1,069				1,069
January 2026 Note derivative liability – related party											1,467				1,467
$1.9 Million Note											1,530				1,530
March 2026 Bridge Note											9,500				9,500
Forward purchase agreement liabilities			—				—				5,107				5,107
SAFE Agreement with related party			—				—				579				579
Private placement warrants			—				—				1,504				1,504
Working capital warrants			—				—				172				172
Public warrants			2,070				—				—				2,070
Deferred Cobalt Consideration Shares			—				—				6,331				6,331
Deferred Ambia Consideration Shares			—				—				13,936				13,936
Total		$	2,070			$	—			$	107,974			$	110,044

		As of December 28, 2025
		Level 1				Level 2				Level 3				Total
Financial Assets
Restricted cash		$	3,841			$	—			$	—			$	3,841
Total		$	3,841			$	—			$	—			$	3,841
Financial Liabilities
July 2024 Notes derivative liability ⁽¹⁾		$	—			$	—			$	19,604			$	19,604
July 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				12,615				12,615
September 2024 Notes derivative liability ⁽¹⁾			—				—				37,930				37,930
September 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				5,870				5,870
July 2025 Note derivative liability– related party ⁽¹⁾			—				—				3,246				3,246
September 2025 Notes derivative liability ⁽¹⁾			—				—				14,756				14,756
November 2025 Note derivative liability – related party ⁽¹⁾			—				—				1,488				1,488
Forward purchase agreement liabilities			—				—				3,965				3,965
SAFE Agreement with related party			—				—				535				535
Private placement warrants			—				—				1,692				1,692
Working capital warrants			—				—				194				194
Public warrants			2,475				—				—				2,475
Deferred Sunder Consideration Shares			10,840				—				—				10,840
Deferred Ambia Consideration Shares			—				—				16,879				16,879
Total		$	13,315			$	—			$	118,774			$	132,089

⁽¹⁾

The derivative liabilities are associated with the Company’s outstanding senior unsecured convertible notes with stated interest rates of 7.0% (the “September 2024 Notes” and “September 2025 Notes”) and 12.0% (the “July 2024 Notes”, “July 2025 Note”, “November 2025 Note” and “January 2026 Note”) all of which are defined in Note 9 – Borrowings and Derivative Liabilities.

The following tables set forth the Company’s financial assets and liabilities that are measured at fair value, on a recurring basis (in thousands):

		As of December 28, 2025
		Level 1				Level 2				Level 3				Total
Financial Assets
Restricted cash		$	3,841			$	—			$	—			$	3,841
Total		$	3,841			$	—			$	—			$	3,841
Financial Liabilities
July 2024 Notes derivative liability ⁽¹⁾		$	—			$	—			$	19,604			$	19,604
July 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				12,615				12,615
September 2024 Notes derivative liability ⁽¹⁾			—				—				37,930				37,930
September 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				5,870				5,870
July 2025 Note derivative liability– related party ⁽¹⁾			—				—				3,246				3,246
September 2025 Notes derivative liability ⁽¹⁾			—				—				14,756				14,756
November 2025 Note derivative liability – related party ⁽¹⁾			—				—				1,488				1,488
Forward purchase agreement liabilities			—				—				3,965				3,965
SAFE Agreement with related party			—				—				535				535
Private placement warrants			—				—				1,692				1,692
Working capital warrants			—				—				194				194
Public warrants			2,475				—				—				2,475
Deferred Sunder Consideration Shares			10,840				—				—				10,840
Deferred Ambia Consideration Shares			—				—				16,879				16,879
Total		$	13,315			$	—			$	118,774			$	132,089

		As of December 29, 2024
		Level 1				Level 2				Level 3				Total
Financial Assets
Restricted cash		$	3,841			$	—			$	—			$	3,841
Total		$	3,841			$	—			$	—			$	3,841
Financial Liabilities
July 2024 Notes derivative liability ⁽¹⁾		$	—			$	—			$	13,563			$	13,563
July 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				21,127				21,127
September 2024 Notes derivative liability ⁽¹⁾			—				—				55,474				55,474
September 2024 Notes derivative liability – related parties ⁽¹⁾			—				—				6,958				6,958
Forward purchase agreement liabilities ⁽²⁾			—				—				3,494				3,494
SAFE Agreement with related party			—				—				384				384
Private placement warrants			—				—				627				627
Working capital warrants			—				—				72				72
Public warrants			862				—				—				862
Total		$	862			$	—			$	101,699			$	102,561

⁽¹⁾	The derivative liabilities are associated with the Company’s outstanding senior unsecured convertible notes with stated interest rates of 7.0% (the “September 2024 Notes” and “September 2025 Notes”) and 12.0% (the “July 2024 Notes”, “July 2025 Note”, and “November 2025 Note”) all of which are defined in Note 10 – Borrowings and Derivative Liabilities.

⁽²⁾	Includes $1.3 million due to related parties as of and December 29, 2024.

Schedule of Liabilities by Class and Categorized Within Level 3 Under the Fair Value Hierarchy

The reconciliation of liabilities by class and categorized within Level 3 under the fair value hierarchy is as follows for the thirteen week periods ended March 29, 2026 and March 30, 2025 (in thousands):

						Thirteen Weeks Ended March 29, 2026
		Derivative liabilities				Convertible debt at fair value				Forward purchase agreements				SAFE Agreements				Warrant liabilities				Deferred Consideration Shares				Total
Balance as of December 28, 2025		$	95,509			$	—			$	3,965			$	535			$	1,886			$	16,879			$	118,774
Additions			2,297				10,710				—				—				—				6,331				19,338
Conversions			(1,883	)			—				—				—				—				—				(1,883	)
Net (gain) loss recognized within Other non-operating income, net in the consolidated statement of operations			(26,608	)			320				1,142				44				(210	)			(2,943	)			(28,255	)
Balance as of March 29, 2026		$	69,315			$	11,030			$	5,107			$	579			$	1,676			$	20,267			$	107,974

		Thirteen Weeks Ended March 30, 2025
		Derivative liabilities				Forward purchase agreements				SAFE Agreements				Warrant liabilities				Total
Balance as of December 29, 2024		$	97,122			$	3,494			$	384			$	699			$	101,699
Additions			—				—				—				—				—
Conversions			—				—				—				—				—
Net (gain) loss recognized within Other non-operating income, net in the consolidated statement of operations			(15,127	)			(268	)			20				488				(14,887	)
Balance as of March 30, 2025		$	81,995			$	3,226			$	404			$	1,187			$	86,812

The reconciliation of liabilities by class and categorized within Level 3 under the fair value hierarchy is as follows for the fiscal years ended December 28, 2025 and December 29, 2024 (in thousands):

		Fiscal Year Ended December 28, 2025
		Derivative liabilities				Forward Purchase Agreements				SAFE Agreements				Warrant liabilities				Deferred Ambia Consideration Shares				Total
Balance as of December 29, 2024		$	97,122			$	3,494			$	384			$	699			$	—			$	101,699
Additions			20,808				—				—				—				16,879				37,687
Conversions			(10,931	)			—				—				—				—				(10,931	)
Net (gain)/loss recognized within Other non-operating income, net in the consolidated statement of operations			(11,490	)			471				151				1,187				—				(9,681	)
Balance as of December 28, 2025		$	95,509			$	3,965			$	535			$	1,886			$	16,879			$	118,774

		Fiscal Year Ended December 29, 2024
		Derivative liabilities				Forward Purchase Agreements				SAFE Agreements				Warrant liabilities				Total
Balance as of December 31, 2023		$	—			$	3,831			$	—			$	10,960			$	14,791
Additions			131,108				—				6,000				—				137,108
Conversions			—				—				(6,250	)			(7,306	)			(13,556	)
Net (gain)/loss recognized within Other non-operating income, net in the consolidated statement of operations			(33,986	)			(337	)			634				(2,955	)			(36,644	)
Balance as of December 29, 2024		$	97,122			$	3,494			$	384			$	699			$	101,699

Schedule of Derivative Liabilities

The assumptions used to value the derivative liabilities as of March 29, 2026 were as follows:

		12.0% Senior Unsecured Convertible Notes																7.0% Senior Unsecured Convertible Notes
		July 2024 Notes⁽¹⁾				July 2025 Note				November 2025 Note				January 2026 Note				September 2024 Notes⁽¹⁾				September 2025 Notes⁽¹⁾
Coupon rate			12.0	%			12.0	%			12.0	%		$	12.0	%			7.0	%			7.0	%
Initial conversion rate			595.24				558.66				626.96				540.54				467.84				467.84
Initial conversion price		$	1.68			$	1.79			$	1.60			$	1.85			$	2.14			$	2.14
Common stock price		$	1.25			$	1.25			$	1.25			$	1.25			$	1.25			$	1.25
Risk-free interest rate			4.00	%			4.00	%			3.96	%			4.00	%			3.96	%			3.96	%
Volatility			88.1	%			88.8	%			87.5	%			89.2	%			90.7	%			90.7	%
Dividend yield			0.00	%			0.00	%			0.00	%			0.00	%			0.00	%			0.00	%

The assumptions used to value the derivative liabilities as of December 28, 2025 were as follows:

		12.0% Senior Unsecured Convertible Notes												7.0% Senior Unsecured Convertible Notes
		July 2024 Notes⁽¹⁾				July 2025 Note				November 2025 Note				September 2024 Notes⁽¹⁾				September 2025 Notes⁽¹⁾
Coupon rate			12.0	%			12.0	%			12.0	%			7.0	%			7.0	%
Initial conversion rate			595.24				558.66				626.96				467.84				467.84
Initial conversion price		$	1.68			$	1.79			$	1.60			$	2.14			$	2.14
Common stock price		$	1.62			$	1.62			$	1.62			$	1.62			$	1.62
Risk-free interest rate			3.6	%			3.6	%			3.6	%			3.58	%			3.58	%
Volatility			82.2	%			83.2	%			81.3	%			85.6	%			85.6	%
Dividend yield			0.00	%			0.00	%			0.00	%			0.00	%			0.00	%

⁽¹⁾

The conversion option is derived based upon the above assumptions plus a make-whole provision which is based upon changes in the Company’s stock price and the conversion date.

The assumptions used to value the derivative liabilities as of December 28, 2025 were as follows:

		12.0% Senior Unsecured Convertible Notes												7.0% Senior Unsecured Convertible Notes
		July 2024 Notes				July 2025 Note				November 2025 Note				September 2024 Notes				September 2025 Notes
Coupon rate			12.0	%			12.0	%			12.0	%			7.0	%			7.0	%
Conversion rate			595.24				558.66				626.96				467.84				467.84
Conversion price		$	1.68			$	1.79			$	1.60			$	2.14			$	2.14
Common stock price		$	1.62			$	1.62			$	1.62			$	1.62			$	1.62
Risk-free interest rate			3.6	%			3.6	%			3.6	%			3.58	%			3.58	%
Volatility			82.2	%			83.2	%			81.3	%			85.6	%			85.6	%
Dividend yield			0.00	%			0.00	%			0.00	%			0.00	%			0.00	%

The assumptions used to value the derivative liabilities as of December 29, 2024 were as follows:

		Senior Unsecured Convertible Notes
		12.0% Notes				7.0% Notes
		July 2024 Notes				September 2024 Notes
Coupon rate			12.0	%			7.0	%
Conversion rate			595.24				467.84
Conversion price		$	1.68			$	2.14
Common stock price		$	1.81			$	1.81
Risk-free interest rate			4.43	%			4.43	%
Volatility			62.0	%			66.6	%
Dividend yield			0.00	%			0.00	%

Schedule of Key Inputs for the Simulation Include Stock Price

The key inputs for the simulation include stock price, simulation period and volatility of the Company’s common stock and were as follows as of March 29, 2026:

		$1.9 Million Note				March 2026 Bridge Note
VWAP stock price		$	1.24			$	1.24
Simulation period			0.83 years				0.94 years
Risk-free rate			3.76	%			3.77	%
Volatility			81.4	%			83.3	%
Credit risk-adjusted rate			41.4	%			73.4	%

The Company valued the private placement and working capital warrants, based on a binomial lattice model, which included the following inputs:

		As of
		March 29,				December 28,
		2026				2025
Expected term			2.31 years				2.56 years
Stock price		$	1.25			$	1.62
Exercise price		$	11.50			$	11.50
Expected volatility			268.3	%			179.0	%
Risk-free rate			3.90	%			3.50	%
Expected dividend yield			0.00	%			0.00	%

FPAs are measured at fair value on a recurring basis using a Monte Carlo simulation analysis based upon the following inputs:

		As of
		March 29,				December 28,
		2026				2025
VWAP stock price		$	1.24			$	1.66
Simulation period			0.30 years				0.55 years
Risk-free rate			3.73	%			3.57	%
Volatility			58.0	%			77.3	%

FPAs are measured at fair value on a recurring basis using a Monte Carlo simulation analysis based upon the following inputs:

		As of
		December 28,				December 29,
		2025				2024
VWAP stock price		$	1.66			$	1.78
Simulation period			0.55 years				0.55 years
Risk-free rate			3.57	%			4.28	%
Volatility			77.3	%			117.0	%

The Company valued the private placement and working capital warrants, based on a binomial lattice model, which included the following inputs:

		As of
		December 28,				December 29,
		2025				2024
Expected term			2.56 years				3.56 years
Stock price		$	1.62			$	1.81
Exercise price		$	11.50			$	11.50
Expected volatility			179.0	%			68.1	%
Risk-free rate			3.50	%			4.39	%
Expected dividend yield			0.00	%			0.00	%

Schedule of Financial Liabilities that are not Measured at Fair Value

The following tables set forth the Company’s financial liabilities that are not measured at fair value and are considered a Level 3 instrument in the fair value hierarchy (in thousands):

		As of March 29, 2026
		Principal amount ⁽¹⁾				Unamortized debt discount and debt issuance costs				Net carrying amount excluding capitalized interest ⁽¹⁾				Fair value
12.0% senior unsecured convertible notes
July 2024 Notes		$	27,973			$	(5,655	)		$	22,318			$	26,724
July 2024 Notes – related parties			18,000				(10,054	)			7,946				17,086
Subtotal July 2024 Notes			45,973				(15,709	)			30,264				43,810
July 2025 Note – related party			5,000				(3,481	)			1,519				4,494
November 2025 Note – related party			2,000				(1,483	)			517				1,971
January 2026 Note – related party			3,300				(2,262	)			1,038				2,955

7.0% senior unsecured convertible notes
September 2024 Notes			53,793				(37,851	)			15,942				45,830
September 2024 Notes – related parties			8,750				(5,946	)			2,804				7,461
Subtotal September 2024 Notes			62,543				(43,797	)			18,746				53,291
September 2025 Notes			22,000				(18,425	)			3,575				18,793
Total		$	140,816			$	(85,157	)		$	55,659			$	125,314

		As of December 28, 2025
		Principal amount ⁽¹⁾				Unamortized debt discount and debt issuance costs				Net carrying amount excluding capitalized interest ⁽¹⁾				Fair value
12.0% senior unsecured convertible notes
July 2024 Notes		$	27,973			$	(5,832	)		$	22,141			$	33,165
July 2024 Notes – related parties			18,000				(10,369	)			7,631				21,204
Subtotal July 2024 Notes			45,973				(16,201	)			29,772				54,369
July 2025 Note – related party			5,000				(3,557	)			1,443				5,641
November 2025 Note – related party			2,000				(1,509	)			491				2,360

7.0% senior unsecured convertible notes
September 2024 Notes			56,543				(42,211	)			14,332				59,425
September 2024 Notes – related parties			8,750				(6,404	)			2,346				8,880
Subtotal September 2024 Notes			65,293				(48,615	)			16,678				68,305
September 2025 Notes			22,000				(18,646	)			3,354				24,227
Total		$	140,266			$	(88,528	)		$	51,738			$	154,902

⁽¹⁾	Excludes capitalized interest (coupon interest, default interest and failure to file interest) of $9.6 million and $10.8 million as of March 29, 2026, and December 28, 2025, respectively, included in the July 2024 Notes.

The following table sets forth the Company’s financial liabilities that were not measured at fair value and are considered a Level 3 instrument in the fair value hierarchy (in thousands):

		As of December 28, 2025
		Principal amount ⁽¹⁾				Unamortized debt discount and debt issuance costs				Net carrying amount excluding capitalized interest ⁽¹⁾				Fair value
12.0% senior unsecured convertible notes
July 2024 Notes		$	27,973			$	(5,832	)		$	22,141			$	33,165
July 2024 Notes – related parties			18,000				(10,369	)			7,631				21,204
Subtotal July 2024 Notes			45,973				(16,201	)			29,772				54,369
July 2025 Note – related party			5,000				(3,557	)			1,443				5,641
November 2025 Note – related party			2,000				(1,509	)			491				2,360

7.0% senior unsecured convertible notes
September 2024 Notes			56,543				(42,211	)			14,332				59,425
September 2024 Notes – related parties			8,750				(6,404	)			2,346				8,880
Subtotal September 2024 Notes			65,293				(48,615	)			16,678				68,305
September 2025 Notes			22,000				(18,646	)			3,354				24,227
Total		$	140,266			$	(88,528	)		$	51,738			$	154,902

		As of December 29, 2024
		Principal amount ⁽¹⁾				Unamortized debt discount and debt issuance costs				Net carrying amount excluding capitalized interest ⁽¹⁾				Fair value
12.0% senior unsecured convertible notes
July 2024 Notes		$	17,973			$	(6,205	)		$	11,768			$	21,390
July 2024 Notes – related parties			28,000				(10,785	)			17,215				33,323
Subtotal July 2024 Notes			45,973				(16,990	)			28,983				54,713

7.0% senior unsecured convertible notes
September 2024 Notes			71,800				(66,164	)			5,636				77,245
September 2024 Notes – related parties			8,000				(7,524	)			476				8,583
Subtotal September 2024 Notes			79,800				(73,688	)			6,112				85,828
Total		$	125,773			$	(90,678	)		$	35,095			$	140,541

(1)	Excludes capitalized interest (coupon interest, default interest and failure to file interest) of $10.8 million and $13.6 million as of December 28, 2025 and December 29, 2024, respectively, included in the July 2024 Notes.

Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.

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