0000950170-24-021155 | 10-K | XBRL Viewer

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Leases - Summary of Supplemental Disclosure of Cash Flow Information Related To Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 2,246	$ 1,948	$ 1,901

Goodwill and Intangible Assets - Future Amortization Expense of Intangible Assets (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2024	$ 203
2025	203
2026	203
2027	203
2028	203
Thereafter	1,339
Carrying Value	$ 2,354

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (25,028)	$ (36,231)	$ (44,215)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Property, Plant and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 195,234	$ 32,352
Less: Accumulated depreciation and amortization	(21,293)	(13,129)
Property, plant and equipment, net	173,941	19,223
Transplant Aicraft [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	141,855
Flight School Aircraft [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	3,484
OCS Consoles [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	14,491	10,878
Manufacturing Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	6,898	3,721
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	3,021	2,064
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	1,875	671
Office Trade Show And Training Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	4,006	2,121
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	13,354	12,415
Construction-In-Progress [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 6,250	$ 482

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Aug. 16, 2023
Goodwill [Line Items]
Carrying amount of goodwill	$ 11,990,000
Amortization expense of intangible assets	100,000
Impairments to goodwill	0
Summit [Member]
Goodwill [Line Items]
Carrying amount of goodwill	$ 12,000,000	$ 11,990,000

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

Income Taxes - Summary of Changes in the Valuation Allowance for Deferred Tax Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Valuation allowance as of beginning of year	$ (121,891)	$ (116,164)	$ (101,029)
Increases recorded to income tax provision	(19,095)	(5,727)	(15,135)
Valuation allowance as of end of year	$ (140,986)	$ (121,891)	$ (116,164)

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

12.

Leases

The Company leases its office, laboratory and manufacturing space under two noncancelable leases that expire in December 2027 and include a lease incentive, fixed payment escalations, and rent holidays. The leases include an option to renew for an additional five years. The option to extend the lease term was not included in the right-of-use asset and the lease liability as it was not reasonably certain of being exercised. The Company classified the leases as operating leases under ASC 842. Annual base rent increases at an average rate of 2.5% each year until the end of the term. The Company is also obligated to pay the landlord certain costs, taxes, and operating expenses, subject to certain exclusions. As these costs are generally variable in nature, they are not included in the measurement of the right-of-use asset and related lease liability. In June 2023, the Company amended one of its lease agreements to add space through the remainder of the lease term and under the existing terms of the lease.

In connection with the acquisition of Summit, the Company acquired a 20-year operating lease with one 10-year renewal option, for space at the Bozeman Yellowstone International Airport in Bozeman, Montana where the Company is constructing a commercial aircraft hangar (see Note 3). The Company also leases office space for its NOP and hangar space for its aircraft at various locations in the United States under short-term leases.

The components of the Company’s lease expense under ASC 842 are as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Operating lease cost	$	1,692	$	1,353	$	1,353
Short-term lease cost		1,606		806		159
Variable lease cost		1,495		718		640
	$	4,793	$	2,877	$	2,152

Supplemental disclosure of cash flow information related to the leases were as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Cash paid for amounts included in the measurement of operating lease liabilities	$	2,246	$	1,948	$	1,901

The weighted-average remaining lease term as of December 31, 2023 and 2022 was 4.7 years and 5.0 years, respectively. The weighted-average discount rate as of December 31, 2023 and 2022 was 6.9% and 6.7%, respectively. Because the interest rate implicit in the leases was not readily determinable, the Company’s estimated incremental borrowing rate was used to calculate the present value of the leases. In determining its incremental borrowing rate, the Company considered its credit quality and assessed interest rates available in the market for similar borrowings, adjusted for the impact of collateral over the term of the leases.

Future payments for the Company’s operating lease liabilities as of December 31, 2023 are as follows (in thousands):


Year Ending December 31,
2024	$	2,638
2025		2,704
2026		2,771
2027		2,839
2028		25
Thereafter		610
Total future minimum lease payments		11,587
Less: imputed interest		(1,845	)
Total operating lease liabilities	$	9,742

The following table represents operating lease liabilities on the consolidated balance sheets (in thousands):


	December 31, 2023
Current operating lease liabilities	$	2,035
Operating lease liabilities, net of current portion		7,707
Total operating lease liabilities	$	9,742

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions				12 Months Ended
	Nov. 02, 2023	May 25, 2023	Apr. 15, 2019	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Aug. 31, 2021
Aggregate intrinsic value of stock options exercised				$ 31.0	$ 15.0	$ 16.3
Weighted average grant-date fair value of stock options granted				$ 41.75	$ 11.32	$ 18.63
Unrecognized compensation cost related to unvested employee and director stock-based awards				$ 48.6
Weighted average period for unrecognized compensation cost				2 years 4 months 24 days
Common Stock
Number of shares issued				25,894	30,143	27,849
Restricted stock awards [Member] \| Common Stock
Weighted average grant-date fair value of stock options granted					$ 28.74
Shares granted				10,304		0
Aggregate fair value of restricted stock vested				$ 1.7
Restricted stock vesting				(24,315)	0	0
Performance-based Vesting [Member]
Shares granted				0
Restricted Stock Units [Member] \| Common Stock
Shares granted				357,594	0	0
2019 Stock Plan [Member]
Share-based compensation arrangement by share-based payment award, number of shares authorized			3,428,571
Share based compensation arrangement by share based payment award number of shares available for grant				1,359,742
2019 Stock Plan [Member] \| Common Stock
Share-based compensation arrangement by sharebased payment award, number of additional shares authorized		1,000,000
2019 Stock Plan [Member] \| From 2014 Plan [Member]
Share-based compensation arrangement by share-based payment award, number of shares authorized			1,595,189
2019 Employee Stock Purchase Plan [Member]
Share-based compensation arrangement by share-based payment award, number of shares authorized			371,142
Share based compensation arrangement by share based payment award number of shares available for grant				264,559
Purchase price of common stock, percent			85.00%
Number of shares issued				25,894
2021 Inducement Plan [Member] \| Common Stock
Share-based compensation arrangement by share-based payment award, number of shares authorized							1,000,000
Share-based compensation arrangement by sharebased payment award, number of additional shares authorized	500,000
Share based compensation arrangement by share based payment award number of shares available for grant				607,366
2019 Plan and Inducement Plan [Member] \| Employee Stock Option \| Maximum [Member]
Plans expire term				10 years

Income Taxes - Schedule of Net deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 99,332	$ 92,445
Capitalized research and development expense	14,062	8,109
Acquired in-process research and development expenses	7,275
Research and development tax credit carryforwards	16,195	13,565
Accrued expenses	5,657	2,994
Stock-based compensation expense	6,704	3,492
Lease liability	2,600	2,218
Section 163(j) interest	191	754
Other	400	483
Total deferred tax assets	152,416	124,060
Deferred tax liabilities:
Property, plant and equipment	(9,055)	(885)
Right-of-use assets	(1,721)	(1,284)
Intangible assets	(654)
Total deferred tax liabilities	(11,430)	(2,169)
Valuation allowance	$ (140,986)	$ (121,891)	$ (116,164)	$ (101,029)

Long-Term Debt and Financing Arrangements - Schedule of Convertible Senior Notes (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Convertible senior notes, net of discount and current portion	$ 447,140
Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount	460,000
Debt discount, net of accretion	(12,860)
Net of current portion	$ 460,000

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482900/835-30-50-1

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-Topic 235
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SX 210.4-08(f))
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 3
-Subparagraph (SX 210.12-04(a))
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-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-3

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Reference 5: http://www.xbrl.org/2003/role/exampleRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash	$ 394,812	$ 201,182
Accounts receivable	63,576	27,611
Inventory	44,235	20,605
Prepaid expenses and other current assets	8,031	2,896
Total current assets	510,654	252,294
Property, plant and equipment, net	173,941	19,223
Operating lease right-of-use assets	6,546	5,130
Restricted cash	500	500
Goodwill	11,990
Acquired intangible assets, net	2,354
Other non-current assets	62
Total assets	706,047	277,147
Current liabilities:
Accounts payable	12,717	3,341
Accrued expenses and other current liabilities	38,221	18,635
Deferred revenue	1,961	241
Operating lease liabilities	2,035	1,444
Total current liabilities	54,934	23,661
Convertible senior notes, net	447,140
Long-term debt, net	59,064	58,696
Operating lease liabilities, net of current portion	7,707	7,415
Total liabilities	568,845	89,772
Commitments and contingencies (Note 13)
Stockholders’ equity:
Preferred stock, no par value; 25,000,000 shares authorized; no shares issued or outstanding
Common stock, no par value; 150,000,000 shares authorized; 32,670,803 shares and 32,141,368 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively	641,106	666,277
Accumulated other comprehensive loss	(199)	(225)
Accumulated deficit	(503,705)	(478,677)
Total stockholders’ equity	137,202	187,375
Total liabilities and stockholders’ equity	$ 706,047	$ 277,147

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Number of Shares
Beginning Balance	3,288,791
Granted	639,045
Exercised	(493,935)
Forfeited	(143,913)
Expired	(937)
Ending Balance	3,289,051	3,288,791
Vested and expected to vest as of December 31, 2023	3,289,051
Options exercisable as of December 31, 2023	1,920,240
Weighted Average Exercise Price
Beginning Balance	$ 21.56
Granted	64.37
Exercised	12.46
Forfeited	34.14
Expired	30.57
Ending Balance	30.69	$ 21.56
Vested and expected to vest as of December 31, 2023	30.69
Options exercisable as of December 31, 2023	$ 23.78
Weighted Average Contractual Term
Options Outstanding	7 years 6 months 7 days	7 years 10 months 9 days
Vested and expected to vest as of December 31, 2023	7 years 6 months 7 days
Options exercisable as of December 31, 2023	6 years 10 months 2 days
Aggregate Intrinsic Value
Options Outstanding	$ 159,343	$ 132,076
Vested and expected to vest as of December 31, 2023	159,343
Options exercisable as of December 31, 2023	$ 105,898

Revenue (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Recognized Revenue Net of Payments

The reconciliation of gross product revenue to net product revenue for these certain payments is shown below (in thousands):


	Year Ended December 31,
	2023			2022			2021
Gross product revenue from sales to customers	$	176,047		$	77,854		$	30,780
Less: clinical trial payments		(22	)		(1,380	)		1,123
Total net product revenue	$	176,069		$	79,234		$	29,657

Schedule of Net Revenue by Organ and Country

The Company disaggregates revenue from contracts with customers related to OCS transplant by organ type and geographical area as it believes this presentation best depicts how the nature, amount, timing and uncertainty of the Company’s revenue and cash flows are affected by economic factors, as shown below (in thousands):


	Year Ended December 31,
	2023		2022		2021
OCS Transplant Revenue by country by organ(1)(2):
United States
Lung total revenue	$	10,548	$	7,967	$	9,843
Heart total revenue		59,080		29,902		10,103
Liver total revenue		151,719		46,169		1,915
Total United States OCS transplant revenue		221,347		84,038		21,861
All other countries
Lung revenue		1,272		880		822
Heart revenue		14,012		8,451		7,579
Liver revenue		104		90		—
Total all other countries OCS transplant revenue		15,388		9,421		8,401
Total OCS transplant revenue	$	236,735	$	93,459	$	30,262

(1)

Revenue by country is categorized based on the location of the end customer. Total revenue includes product and service revenue.

(2)

Service revenue unrelated to OCS transplant, which was $4.9 million for the year December 31, 2023, is not included in this table.

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Director [Member]
Related Party Transaction [Line Items]
Compensation expense	$ 0.4	$ 0.4	$ 0.4

Long-Term Debt and Financing Arrangements - Capped Call Transactions - Additional Information (Detail) $ / shares in Units, $ in Thousands		12 Months Ended
	May 11, 2023 USD ($)	Dec. 31, 2023 USD ($) TradingDays $ / shares shares
Debt Instrument [Line Items]
Purchases of capped calls related to convertible senior notes \| $		$ 52,072
Capped Calls [Member]
Debt Instrument [Line Items]
Purchases of capped calls related to convertible senior notes \| $	$ 52,100
Initial conversion price/rate \| $ / shares		$ 94
Capped calls, initial cap price per share \| $ / shares		141.88
Capped calls, subject to anti-dilution adjustments \| shares		4,893,848
Number of trading days subject to automatic exercise \| TradingDays		40
Trading day period, commencing date		Apr. 03, 2028

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Long-Term Debt and Financing Arrangements (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Convertible Senior Notes

Convertible senior notes consisted of the following (in thousands):


	December 31, 2023
Principal amount of convertible senior notes	$	460,000
Less: Current portion of convertible senior notes		—
Convertible senior notes, net of current portion		460,000
Debt discount, net of accretion		(12,860	)
Convertible senior notes, net of discount and current portion	$	447,140

Schedule of Long-term Debt Instruments

Long-term debt consisted of the following (in thousands):


	December 31,
	2023			2022
Principal amount of long-term debt	$	60,000		$	60,000
Less: Current portion of long-term debt		—			—
Long-term debt, net of current portion		60,000			60,000
Debt discount, net of accretion		(936	)		(1,304	)
Long-term debt, net of discount and current portion	$	59,064		$	58,696

Canadian Imperial Bank of Commerce Credit Agreement

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69B

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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Depreciation and amortization expense	$ 8,177	$ 3,478	$ 1,817
Property, Plant and Equipment [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization expense	$ 8,100	$ 3,500	$ 1,800

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 31, 2020	$ 103,891	$ 502,217	$ (95)	$ (398,231)
Balance, Shares at Dec. 31, 2020		27,175,305
Issuance of common stock upon the exercise of common stock options	974	$ 974
Issuance of common stock upon the exercise of common stock options, Shares		588,461
Issuance of common stock in connection with employee stock purchase plan	419	$ 419
Issuance of common stock in connection with employee stock purchase plan, Shares		27,849
Stock-based compensation expense	6,878	$ 6,878
Foreign currency translation adjustment	(46)		(46)
Unrealized gains (losses) on marketable securities	(47)		(47)
Net loss	(44,215)			(44,215)
Balance at Dec. 31, 2021	67,854	$ 510,488	(188)	(442,446)
Balance, Shares at Dec. 31, 2021		27,791,615
Issuance of common stock upon the exercise of common stock options	4,667	$ 4,667
Issuance of common stock upon the exercise of common stock options, Shares		507,795
Issuance of common stock in connection with employee stock purchase plan	509	$ 509
Issuance of common stock in connection with employee stock purchase plan, Shares		30,143
Issuance of common stock in public offering, net of discounts and issuance costs	139,854	$ 139,854
Issuance of common stock in public offering, net of discounts and issuance costs, Shares		3,737,500
Issuance of restricted common stock, Shares		26,093
Restricted common stock forfeitures, Shares		(1,778)
Issuance of common stock in connection with exercise of warrants	438	$ 438
Issuance of common stock in connection with exercise of warrants, Shares		50,000
Stock-based compensation expense	10,321	$ 10,321
Foreign currency translation adjustment	(73)		(73)
Unrealized gains (losses) on marketable securities	36		36
Net loss	(36,231)			(36,231)
Balance at Dec. 31, 2022	187,375	$ 666,277	(225)	(478,677)
Balance, Shares at Dec. 31, 2022		32,141,368
Issuance of common stock upon the exercise of common stock options	$ 6,155	$ 6,155
Issuance of common stock upon the exercise of common stock options, Shares	493,935	493,935
Issuance of common stock in connection with employee stock purchase plan	$ 955	$ 955
Issuance of common stock in connection with employee stock purchase plan, Shares		25,894
Issuance of restricted common stock, Shares		10,304
Restricted common stock forfeitures, Shares		(698)
Stock-based compensation expense	19,791	$ 19,791
Purchases of capped calls related to convertible senior notes	(52,072)	(52,072)
Foreign currency translation adjustment	26		26
Net loss	(25,028)			(25,028)
Balance at Dec. 31, 2023	$ 137,202	$ 641,106	$ (199)	$ (503,705)
Balance, Shares at Dec. 31, 2023		32,670,803

Acquisition of Summit - Summary of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Aug. 16, 2023
Business Acquisition [Line Items]
Goodwill	$ 11,990
Summit [Member]
Business Acquisition [Line Items]
Accounts receivable		$ 2,089
Other current assets		1,040
Property, plant and equipment		5,922
Right-of-use asset		288
Intangible assets		2,430
Goodwill	$ 12,000	11,990
Total assets acquired		23,759
Accounts payable and other current liabilities		(6,917)
Deferred tax liabilities		(1,660)
Operating lease liabilities		(288)
Total allocation of purchase price consideration, net of cash acquired		$ 14,894

Revenue

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Revenue

14. Revenue

The Company has determined that the payments made to the customer for reimbursement of clinical trial materials and customer’s costs incurred to execute specific clinical trial protocols related to the Company’s OCS products do not provide the Company with a distinct good or service transferred by the customer, and therefore such payments are recorded as a reduction of revenue from the customer in the Company’s consolidated statements of operations. The Company records the reduction of revenue in the same period as the revenue is recognized and records a corresponding accrual for its estimate of the payments. As clinical trials reach the closeout phase, the Company updates its accrual estimates with corresponding adjustments to revenue. The Company will continue to update its clinical trial accrual estimates as information related to clinical trial payments is received.

The reconciliation of gross product revenue to net product revenue for these certain payments is shown below (in thousands):


	Year Ended December 31,
	2023			2022			2021
Gross product revenue from sales to customers	$	176,047		$	77,854		$	30,780
Less: clinical trial payments		(22	)		(1,380	)		1,123
Total net product revenue	$	176,069		$	79,234		$	29,657

The Company determined that payments made to customers to obtain information related to post-approval studies or existing standard-of-care protocols (i.e., unrelated to the Company’s OCS products) meet the criteria to be classified as a cost because the Company receives a distinct good or service transferred by the customer separate from the customer’s purchase of the Company’s OCS products and the consideration paid to the customer represents the fair value of the distinct good or service received. As a result, such payments made to the customers are recorded as operating expenses. The Company recorded payments made to customers related to post-approval studies and for documentation related to existing standard-of-care protocols of $0.9 million, $1.0 million and $2.1 million for the years ended December 31, 2023, 2022 and 2021, respectively, as operating expenses.

Summit makes payments to its aircraft management customers who had opted in to Summit's charter program. Summit pays the aircraft owner a fee for the use of the aircraft for charter flight services. The Company determined that fees incurred for the use of aircraft management customers' aircraft meet the criteria to be classified as a cost because the Company receives a distinct good or service transferred by the customer separate from the customer’s purchase of Summit's aircraft management services and the consideration to the customer represents the fair value of the distinct good or service received. As a result, such fees are recorded as cost of sales. The Company recorded expense for the use of customers' aircraft of $1.1 million for the year ended December 31, 2023. As part of the Summit integration, Summit's legacy aircraft management customers are being transitioned to third parties and following this transition, the Company will no longer make such payments to customers.

Disaggregated Revenue


	Year Ended December 31,
	2023		2022		2021
OCS Transplant Revenue by country by organ(1)(2):
United States
Lung total revenue	$	10,548	$	7,967	$	9,843
Heart total revenue		59,080		29,902		10,103
Liver total revenue		151,719		46,169		1,915
Total United States OCS transplant revenue		221,347		84,038		21,861
All other countries
Lung revenue		1,272		880		822
Heart revenue		14,012		8,451		7,579
Liver revenue		104		90		—
Total all other countries OCS transplant revenue		15,388		9,421		8,401
Total OCS transplant revenue	$	236,735	$	93,459	$	30,262

(1)

Revenue by country is categorized based on the location of the end customer. Total revenue includes product and service revenue.

(2)

Service revenue unrelated to OCS transplant, which was $4.9 million for the year December 31, 2023, is not included in this table.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Statement of Stockholders' Equity [Abstract]
Discounts and issuance costs	$ 676

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue:
Total revenue	$ 241,623	$ 93,459	$ 30,262
Cost of revenue:
Total cost of revenue	87,530	28,187	9,103
Gross profit	154,093	65,272	21,159
Operating expenses:
Research, development and clinical trials	36,055	26,812	22,304
Acquired in-process research and development expenses	27,212
Selling, general and administrative	119,553	69,897	38,283
Total operating expenses	182,820	96,709	60,587
Loss from operations	(28,727)	(31,437)	(39,428)
Other income (expense):
Interest expense	(10,791)	(3,726)	(3,874)
Other income (expense), net	12,847	(1,002)	(877)
Total other income (expense), net	2,056	(4,728)	(4,751)
Loss before income taxes	(26,671)	(36,165)	(44,179)
(Provision) benefit for income taxes	1,643	(66)	(36)
Net loss	$ (25,028)	$ (36,231)	$ (44,215)
Net loss per share attributable to common stockholders, basic	$ (0.77)	$ (1.23)	$ (1.6)
Net loss per share attributable to common stockholders, diluted	$ (0.77)	$ (1.23)	$ (1.6)
Weighted average common shares outstanding, basic	32,517,372	29,556,633	27,616,839
Weighted average common shares outstanding, diluted	32,517,372	29,556,633	27,616,839
Net product revenue [Member]
Revenue:
Total revenue	$ 176,069	$ 79,234	$ 29,657
Cost of revenue:
Total cost of revenue	41,015	16,970	9,031
Service Revenue [Member]
Revenue:
Total revenue	65,554	14,225	605
Cost of revenue:
Total cost of revenue	$ 46,515	$ 11,217	$ 72

Revenue - Schedule of Net Revenue by Organ and Country (Parenthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 241,623	$ 93,459	$ 30,262
Unrelated to OCS Transplant [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 4,900

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

+ Details

Subsequent Events

12 Months Ended

Dec. 31, 2023

Subsequent Events [Abstract]

Subsequent Events

16. Subsequent Events

In separate transactions in January 2024 and February 2024, the Company acquired two fixed-wing aircraft from two separate sellers for a total purchase price of $26.6 million. The Company plans to utilize these aircraft as part of the NOP's aviation transportation services.

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (25,028)	$ (36,231)	$ (44,215)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	8,177	3,478	1,817
Stock-based compensation expense	19,791	10,321	6,878
Acquired in-process research and development expenses	27,212
Deferred taxes	(1,660)
Loss on extinguishment of debt		575
Loss on sale of marketable securities		107
Non-cash interest expense and end of term accretion expense	2,128	465	540
Non-cash lease expense	1,041	717	829
Net amortization of premiums on marketable securities		381	1,356
Unrealized foreign currency transaction (gains) losses	(342)	1,129	928
Changes in operating assets and liabilities, net of acquired assets and liabilities:
Accounts receivable	(33,816)	(21,678)	840
Inventory	(28,092)	(8,024)	(4,894)
Prepaid expenses and other current assets	(2,101)	2,521	(3,151)
Other non-current assets	(54)
Accounts payable	6,957	(3,270)	5,090
Accrued expenses and other current liabilities	14,250	3,437	4,875
Deferred revenue	83		7
Operating lease liabilities	(1,574)	255	236
Net cash used in operating activities	(13,028)	(45,817)	(28,864)
Cash flows from investing activities:
Purchases of property, plant and equipment	(151,847)	(11,907)	(3,519)
Purchase of business, net of cash acquired	(14,894)
Purchase of in-process research and development assets	(27,212)
Purchases of marketable securities		(10,496)	(72,024)
Proceeds from sales and maturities of marketable securities		76,916	104,810
Net cash provided by (used in) investing activities	(193,953)	54,513	29,267
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net of issuance costs paid of $14,620	445,380
Purchases of capped calls related to convertible senior notes	(52,072)
Proceeds from issuance of long-term debt, net of issuance costs		58,509
Repayments of long-term debt		(36,050)
Proceeds from issuance of common stock in public offering, net of underwriting discounts and commissions and issuance costs paid		139,854
Proceeds from issuance of common stock upon exercise of stock options	6,155	4,667	974
Proceeds from issuance of common stock upon exercise of warrants		438
Proceeds from issuance of common stock in connection with employee stock purchase plan	955	509	419
Net cash provided by financing activities	400,418	167,927	1,393
Effect of exchange rate changes on cash, cash equivalents and restricted cash	193	(1,021)	(797)
Net increase in cash, cash equivalents and restricted cash	193,630	175,602	999
Cash, cash equivalents and restricted cash, beginning of period	201,682	26,080	25,081
Cash, cash equivalents and restricted cash, end of period	395,312	201,682	26,080
Supplemental disclosure of cash flow information:
Cash paid for interest	8,089	3,260	3,334
Supplemental disclosure of non-cash activities:
Transfers of inventory to property, plant and equipment	4,574	2,135	1,823
Purchases of property, plant and equipment included in accounts payable and accrued expenses	2,454	62	1,200
Operating lease liabilities arising from obtaining right-of-use assets	2,171
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	394,812	201,182	25,580
Restricted cash	500	500	500
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 395,312	$ 201,682	$ 26,080

Stock-Based Compensation - Summary of Restricted Common Stock Activity (Details) - Common Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restricted stock awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested Stock, Beginning Balance	24,315
Unvested Stock, Issued \ Granted	10,304		0
Unvested Stock, Vested	(24,315)	0	0
Unvested Stock, Forfeited	(698)
Unvested Stock, Ending Balance	9,606	24,315
Weighted Average Grant Date Fair Value
Unvested Stock, Beginning Balance	$ 28.79
Unvested Stock, Issued \ Granted	72.75
Unvested Stock, Vested	28.79
Unvested Stock, Forfeited	71.6
Unvested Stock, Ending Balance	$ 72.83	$ 28.79
Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested Stock, Issued \ Granted	357,594	0	0
Unvested Stock, Forfeited	(29,228)
Unvested Stock, Ending Balance	328,366
Weighted Average Grant Date Fair Value
Unvested Stock, Issued \ Granted	$ 63.74
Unvested Stock, Forfeited	56.53
Unvested Stock, Ending Balance	$ 64.38

Acquisition of Summit

12 Months Ended

Dec. 31, 2023

Business Combinations [Abstract]

Acquisition of Summit

On August 16, 2023, the Company acquired Summit pursuant to the terms of an equity purchase agreement. Summit was a charter flight operator based in Bozeman, Montana. The acquisition enabled TransMedics to add aviation transportation services to its NOP and become a comprehensive national provider of donor organ retrieval and delivery in the United States.

The acquisition was accounted for as a purchase of a business under ASC Topic 805, Business Combinations. Under the acquisition method of accounting, the assets and liabilities were recorded as of the acquisition date, at their respective fair values. The preliminary purchase consideration of $14.9 million reflected an upfront cash payment of $18.0 million, net of cash acquired and working capital adjustments.

The Company’s consolidated financial statements reflect the preliminary allocation of the purchase price to the assets and liabilities assumed based on fair value as of the date of the acquisition. The Company's estimate of preliminary purchase consideration is subject to change upon finalizing working capital adjustments. The Company’s preliminary estimate of the fair value of specifically identifiable assets acquired and liabilities assumed as of the date of acquisition is subject to change upon finalizing its valuation analysis. During the three months ended December 31, 2023, the Company recorded an adjustment to goodwill of $0.3 million, representing an adjustment to its estimate of the fair value of accounts payable and deferred tax liabilities as of the acquisition date. The final determinations, which are expected to be completed by August 2024, may result in additional changes in the fair value of certain assets and liabilities as compared to these preliminary estimates.

The following tables summarize the preliminary allocation of the purchase price (in thousands):


Assets Acquired and Liabilities Assumed:
Accounts receivable	$	2,089
Other current assets		1,040
Property, plant and equipment		5,922
Right-of-use asset		288
Intangible assets		2,430
Goodwill		11,990
Total assets acquired		23,759
Accounts payable and other current liabilities		(6,917	)
Deferred tax liabilities		(1,660	)
Operating lease liabilities		(288	)
Total allocation of purchase price consideration, net of cash acquired	$	14,894

Property, plant and equipment consist primarily of flight school aircraft and construction-in-progress related to a commercial aircraft hangar that Summit is in the process of constructing. Flight school aircraft were valued using market comparisons adjusted for aircraft-specific condition. The fair value of construction-in-progress approximated its cost.

Intangible assets consisted primarily of a customer relationship asset of $2.3 million related to flight school revenue and was valued using the multi-period excess earnings method, a form of the income approach. Significant assumptions and estimates utilized in this model include the revenue growth rate, contract renewal probability and the discount rate. Intangible assets are being amortized on a straight-line basis to selling, general and administrative over their estimated useful lives of 12 years as of the acquisition date.

Goodwill was recognized for the excess purchase price over the fair value of the net assets acquired. Goodwill is primarily attributable to the workforce of the acquired business (which is not eligible for separate recognition as an identifiable intangible asset) and anticipated synergies between Summit’s existing business processes and the NOP. Goodwill from the acquisition is included within the Company’s one reporting unit and is included in the Company’s enterprise-level annual review for impairment. Goodwill resulting from the acquisition is not deductible for tax purposes.

Deferred tax liabilities relate to the differences between the fair value recognized in purchase accounting and the tax basis of property, plant and equipment and intangible assets. The net deferred tax liability is a source of income to support the recognition of a portion of our existing deferred tax assets. Therefore, the Company recorded a tax benefit of $1.7 million for the release of a portion of its valuation allowance related to the net deferred tax liabilities recorded in purchase accounting.

The Company incurred total transaction costs of $2.0 million for third-party professional services utilized for the acquisition, which are included in selling, general and administrative costs in the consolidated statements of operations. The operating results of the acquired entity have been included in the consolidated financial statements beginning on the acquisition date. Pro forma results of operations for the acquisition have not been presented as they are not material to the Company’s consolidated results of operations.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, revenue recognition, the valuation of inventory, the valuation of assets acquired and liabilities assumed in business combinations, including acquired intangible assets and the resulting goodwill, and the valuation of stock-based awards. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. As of the date of issuance of these consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update estimates, judgments or revise the carrying value of any assets or liabilities. Actual results may differ from those estimates or assumptions.

Risk of Concentrations of Credit, Significant Customers and Significant Suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and accounts receivable. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. As of December 31, 2023 and 2022, the Company had no allowance for credit losses.

Significant customers are those that accounted for 10% or more of the Company’s revenue or accounts receivable. For the year ended December 31, 2023, no customer accounted for more than 10% of revenue. For the years ended December 31, 2022 and 2021, one customer accounted for 14% of revenue and one customer accounted for 11% of revenue, respectively. As of December 31, 2023 and 2022, no customer accounted for 10% or more of accounts receivable.

Certain of the components and subassemblies included in the Company’s products are obtained from a sole source, a single source or a limited group of suppliers, as are sterilization services. Although the Company seeks to reduce dependence on those limited sources of suppliers, manufacturers and service providers, the partial or complete loss of certain of these sources could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships.

Deferred Financing Costs

Deferred financing costs related to a recognized debt liability are recorded as a reduction of the carrying amount of the debt liability and amortized to interest expense using the effective interest method over the repayment term of the debt.

Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents.

Restricted Cash

As of December 31, 2023 and 2022, the Company maintained two letters of credit totaling $0.5 million for the benefit of the landlord of its leased property. The Company was required to maintain a separate cash balance of $0.5 million to secure the letters of credit. Related to this separate cash balance, the Company classified $0.5 million as restricted cash (non-current) on its consolidated balance sheets as of December 31, 2023 and 2022.

Accounts Receivable

Accounts receivable are presented net of an allowance for credit losses, which is an estimate of amounts that may not be collectible. The Company performs ongoing credit evaluations of its customers and monitors economic conditions to identify facts and circumstances that may indicate its receivables are at risk of collection. The Company provides reserves against accounts receivable for estimated credit losses, if any, that may result from a customer’s inability to pay based on the composition of its accounts receivable, current economic conditions and historical credit loss activity. Amounts deemed uncollectible are

charged or written-off against the reserve. As of December 31, 2023 and 2022, the Company had no allowance for credit losses. During the years ended December 31, 2023, 2022 and 2021, the Company did not record any provisions for credit losses. During the year ended December 31, 2022, the Company wrote off less than $0.1 million of accounts receivable balances. During the years ended December 31, 2023 and 2021, the Company did not write off any accounts receivable balances.

Business Combinations

In determining whether an acquisition should be accounted for as a business combination or asset acquisition, the Company first determines whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets. If this is the case, the single identifiable asset or the group of similar assets is not deemed to be a business and the acquisition is accounted for as an asset acquisition. If this is not the case, the Company then further evaluates whether the acquisition includes, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. If so, the Company concludes that the acquisition is a business and accounts for it as a business combination.

The Company accounts for business combinations using the acquisition method of accounting. In accordance with this method, assets acquired and liabilities assumed are recorded at their respective fair values at the acquisition date. The fair value of the consideration paid is assigned to the assets acquired and liabilities assumed based on their respective fair values. Goodwill represents the excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed.

Determining the fair value of assets acquired and liabilities assumed is judgmental in nature and can involve the use of significant estimates and assumptions. Fair value and useful life determinations are based on, among other things, valuations that use information and assumptions provided by management, which consider management’s best estimates of inputs and assumptions that a market participant would use. Actual results may vary from these estimates and may result in adjustments to goodwill and acquisition date fair values of assets and liabilities during a measurement period or upon a final determination of asset and liability fair values, whichever comes first. Adjustments to fair values of assets and liabilities made after the end of the measurement period are recorded within operating results.

Transaction costs related to business combinations are expensed as incurred and are included in general and administrative expense in the consolidated statements of operations.

Goodwill and Acquired Intangible Assets

The Company records goodwill when consideration paid in a business combination exceeds the value of the net assets acquired. The Company’s estimates of fair value are based upon assumptions believed to be reasonable at that time, but that are inherently uncertain and unpredictable. Goodwill is not amortized, but rather is tested for impairment annually in the fourth quarter, or more frequently if facts and circumstances warrant a review, such as significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets.

The Company has determined that there is a single reporting unit for the purpose of conducting this goodwill impairment assessment. The Company has the option of performing either a qualitative or quantitative assessment to determine whether further impairment testing is necessary. If it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, a quantitative impairment test will be required. The quantitative goodwill impairment test requires management to estimate and compare the fair value of the reporting unit with its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets, goodwill is not impaired. If the fair value of the reporting unit is less than the carrying value, the difference is recorded as an impairment loss up to the amount of goodwill.

Intangible assets are recorded at their estimated fair values at the date of acquisition and are reported net of accumulated amortization. The Company amortizes acquired intangible assets with finite lives over their estimated useful lives based on the pattern of consumption of the economic benefits or, if that pattern cannot be readily determined, on a straight-line basis.

Asset Acquisitions

The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the asset or group of assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date.

On August 2, 2023, the Company acquired certain assets related to lung and heart perfusion technology from Bridge to Life Ltd. and its subsidiary Tevosol, Inc., together (“BTL”). The Company intends to further develop these technologies to expand its product offerings and indications for organ transplantation. The Company accounted for the purchase of BTL as an asset acquisition as substantially all of the fair value of gross assets acquired were concentrated on a single set of identifiable activities consisting of lung and heart perfusion technology, referred to as the in-process research and development (“IPR&D”) asset. Due to the stage of development of the IPR&D asset at the date of acquisition, it was not yet probable that there was future economic benefit from this asset. Absent successful clinical results and regulatory approval for the asset applications, there was no alternative future use associated with the asset. Accordingly, the value of the IPR&D asset of $27.2 million was expensed as research and development expense in the consolidated statements of operations.

Property Plant and Equipment

Property, Plant and Equipment

Property, plant and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful life of each asset as follows:


		Estimated Useful Life
Transplant aircraft		10 years
Flight school aircraft		5 years
Manufacturing equipment		5 years
OCS Consoles		5 years
Computer equipment and software		3 years
Laboratory equipment		3 years
Office, trade show and training equipment		5 years
Leasehold improvements		Shorter of term of lease or 15 years

Depreciation and amortization expense of aircraft is recognized over the estimated useful lives of each asset to their salvage value. Salvage values estimated for transplant and flight school aircraft are approximately 50% of the original purchase price.

Costs incurred for OCS Consoles are recorded as inventory unless and until the Company determines that an OCS Console will either be used for the NOP or loaned to a customer for its use, at which time the Company reclassifies the cost of the OCS Console from inventory to property, plant and equipment and begins to depreciate the OCS Console over its estimated useful life. Such depreciation expense is classified as a cost of revenue. The Company retains title to all OCS Consoles loaned to customers.

Costs for capital assets not yet placed into service are capitalized as construction-in-progress and depreciated once placed into service. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is included in loss from operations. Expenditures for repairs and maintenance are charged to expense as incurred.

Impairment of Long-Lived Assets

Long-lived assets consist primarily of property, plant and equipment, right-of-use assets and intangible assets with finite lives. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized in loss from operations when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company did not record any impairment losses on long-lived assets during the years ended December 31, 2023, 2022 and 2021.

Software Development Costs

The Company incurs costs to develop computer software that is embedded in the hardware components of the Company’s OCS Console and OCS Perfusion Sets. Research and development costs related to this software are expensed as incurred, except

for costs of internally developed or externally purchased software that qualify for capitalization. Software development costs incurred subsequent to the establishment of technological feasibility, but prior to the general release of the product, are capitalized and amortized over their estimated useful life. Due to the short time period between achieving technological feasibility and product release and the insignificant amount of costs incurred during such periods, the Company did not capitalize any software development costs during the years ended December 31, 2023, 2022 and 2021.

The Company also capitalizes development costs related to internal-use software when it is probable that the expenditures will result in additional functionality. Costs incurred in the preliminary and post-implementation stages of development are expensed as incurred. Once an application has reached the development stage, internal and external costs, if direct and incremental, are capitalized until the software is substantially complete and ready for its intended use and depreciated over their estimated useful life. Capitalization ceases upon completion of all substantial testing performed to ensure the product is ready for its intended use. The Company did not capitalize any software development costs related to internal-use software during the years ended December 31, 2023, 2022 and 2021.

Inventory

Inventory is valued at the lower of cost or net realizable value. Cost is computed using the first-in, first-out method. The Company regularly reviews inventory quantities on-hand for excess and obsolete inventory and, when circumstances indicate, records charges to write down inventories to their estimated net realizable value, after evaluating historical sales, future demand, market conditions and expected product life cycles. Such charges are classified as cost of revenue in the consolidated statements of operations. Any write-down of inventory to net realizable value creates a new cost basis.

At the end of each reporting period, the Company assesses whether losses should be accrued on long-term manufacturing purchase commitments in accordance with ASC 330, Inventory, which requires that losses that are expected to arise from firm, noncancelable and unhedged commitments for the future purchase of inventory, measured in the same way as inventory losses, should be recognized in the current period in the statements of operations unless they are deemed recoverable through firm sales contacts or when there are other circumstances that reasonably assure continuing sales without price decline. As of the end of each reporting period presented in the accompanying consolidated financial statements, the Company did not identify any potential losses arising from remaining future purchase commitments as compared to estimated future customer sales through the remainder of the term of the manufacturing purchase commitment and, as a result, did not recognize any loss provision for future-period remaining purchase commitments for the year ended December 31, 2023.

Leases

The Company accounts for leases under ASC Topic 842, Leases (“ASC 842”). In accordance with ASC 842, the Company accounts for a contract as a lease when it has the right to control the asset for a period of time while obtaining substantially all of the asset’s economic benefits. The Company determines if an arrangement is a lease or contains an embedded lease at inception. For arrangements that meet the definition of a lease, the Company determines the initial classification and measurement of its right-of-use asset and lease liability at the lease commencement date and thereafter if modified. The lease term includes any renewal options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its estimated secured incremental borrowing rate for that lease term. The Company’s policy is to not record leases with an original term of twelve months or less on its consolidated balance sheets and recognizes those lease payments in the income statement on a straight-line basis over the lease term.

In addition to rent, the leases may require the Company to pay additional costs, such as utilities, maintenance and other operating costs, which are generally referred to as non-lease components. The Company has elected to not separate lease and non-lease components. Only the fixed costs for lease components and their associated non-lease components are accounted for as a single lease component and recognized as part of a right-of-use asset and lease liability. Rent expense for operating leases is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments and is included in operating expense in the consolidated statements of operations.

Revenue from leasing arrangements is not subject to the revenue standard for contracts with customers and remains separately accounted for under ASC 842. In accordance with ASC 842, lessors should classify and account for a lease with variable lease payments that do not depend on a reference index or a rate as an operating lease if the lease would have been classified as a sales-type lease or a direct financing lease and the lessor would have otherwise recognized a day-one loss. The Company’s OCS Console implied rental agreements qualify as sales-type leases with certain variable payments that meet specified criteria such that a day-one loss would be recognized under ASC 842. Therefore, in accordance with ASC 842, such

leases are accounted for as operating leases and the Company does not derecognize the leased asset (the OCS Console) at the time of the sale but depreciates the leased asset over the useful life of the asset.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The carrying values of the Company’s accounts receivable, accounts payable and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities. The carrying value of the Company’s long-term debt approximates its fair value (a level 2 measurement) at each balance sheet date due to its variable interest rate, which approximates a market interest rate. The Company's 1.50% Convertible Senior Notes due 2028 (the "Notes") are carried at the face value less unamortized debt discount and issuance costs on the consolidated balance sheets, and the fair value of the convertible senior notes is presented at each reporting period for disclosure purposes only (see Note 8).

Segment Information

The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company has developed and is commercializing a proprietary system to preserve and deliver human organs for transplant in a near-physiologic condition to address the limitations of cold storage organ preservation. Operating segments are defined as components of an enterprise for which separate financial information is regularly evaluated by the Company’s chief operating decision maker, or decision-making group, in deciding how to allocate resources and assess performance. The Company has determined that its chief operating decision maker is its Chief Executive Officer. The Company’s chief operating decision maker reviews the Company’s financial information on a consolidated basis for purposes of allocating resources and assessing financial performance.

Product Warranties

The Company provides a one-year warranty on its OCS Consoles and disposable sets and replaces or repairs any OCS Console or disposable set that does not function in accordance with the product specifications. OCS Consoles returned to the Company may be refurbished and redeployed. Estimated warranty costs are recorded at the time of shipment of the OCS Console or disposable set. Warranty costs are estimated based on the current expected product replacement or repair cost and expected replacement or repair rates based on historical experience. The Company evaluates its warranty accrual at the end of each reporting period and makes adjustments as necessary. As of December 31, 2023 and 2022, the warranty accrual was less than $0.1 million each.

Revenue Recognition

The Company generates net product revenue primarily from sales of its single-use, organ-specific disposable sets used on its organ-specific OCS Consoles. To a lesser extent, the Company also generates product revenue from the sale of OCS Consoles to customers and the implied rental of OCS Consoles loaned to customers at no charge. For each new transplant procedure, customers purchase an additional OCS disposable set for use on the customer’s existing organ-specific OCS Console. The Company also generates service revenue by providing outsourced organ retrieval, OCS organ management and logistics services under its NOP in the United States.

The Company recognizes revenue from sales to customers applying the following five steps: (1) identification of the contract, or contracts, with a customer, (2) identification of the performance obligations in the contract, (3) determination of the transaction price, (4) allocation of the transaction price to the performance obligations in the contract, and (5) recognition of revenue when, or as, performance obligations are satisfied.

Substantially all of the Company’s customer contracts have multiple-performance obligations that contain deliverables consisting of OCS Perfusion Sets and OCS Solutions. Customer contract deliverables may also include organ retrieval, OCS organ management services and organ transportation under the Company's NOP or an OCS Console, whether sold or loaned to the customer. The Company evaluates each promise within a multiple-performance obligation arrangement to determine whether it represents a distinct performance obligation. The primary performance obligations in the Company’s customer arrangements from which it derives revenue are the OCS Perfusion Sets, the OCS Solutions, the OCS Console, organ retrieval services, OCS organ management services and organ transportation logistics.

When a customer order includes an OCS Console, the Company has determined that customer training and the equipment set-up of the OCS Console, each performed by the Company, are not distinct because they are not sold on a standalone basis and can only be performed by the Company in conjunction with a sale or loan of its OCS Console. In addition, the Company has determined that the OCS Console itself is not distinct because the customer cannot benefit from the OCS Console without the training and equipment set-up having been completed. As a result, when the order includes an OCS Console, the Company has concluded that training, OCS Console equipment set-up, and the OCS Console itself are highly interdependent and represent a single, combined performance obligation. The Company recognizes revenue from the single, combined performance obligation only once the OCS Console has arrived at the customer site and the training and equipment set-up have been completed by the Company.

Customer orders may include the loan of an OCS Console as well as OCS disposable sets used in each transplant procedure. When the Company loans the OCS Console to the customer, it retains title to the console at all times and does not require minimum purchase commitments from the customer related to any OCS products. In such cases, the Company invoices the customer for OCS disposable sets based on customer orders received for each new transplant procedure and the prices set forth in the customer agreement. Over time, the Company typically recovers the cost of the loaned OCS Console through the customer’s continued purchasing and use of additional OCS disposable sets. For these reasons, the Company has determined that part of the arrangement consideration for the disposable set is an implied rental payment for use of the OCS Console. Therefore, the Company allocates the arrangement consideration between the lease deliverables (i.e., the OCS Console) and non-lease deliverables (i.e., the OCS disposable sets) based on the relative estimated standalone selling price of each distinct performance obligation. To date, the amounts allocated to lease deliverables have been insignificant.

Revenue from sales to customers of OCS Perfusion Sets, OCS Solutions and OCS Consoles is classified as net product revenue in the Company's consolidated statements of operations. Revenue from sales to customers of organ retrieval, OCS organ management services and organ transportation logistics is classified as service revenue in the Company’s consolidated statements of operations.

Revenue is recognized when control is transferred to the customer in an amount that reflects the consideration the Company expects to be entitled to in exchange for the product or services. When a customer order includes disposable sets and organ retrieval, OCS organ management or logistics services, the Company has determined that the disposable sets and services constitute separate performance obligations and recognizes revenue as the disposable sets and services are each delivered to the customer.

Payments Made to Customers

Under some of the Company’s customer clinical trial agreements, the Company makes payments to its customers for reimbursements of clinical trial materials and for specified clinical documentation related to the customer’s use of its OCS products. The Company also makes payments to customers involved in post-approval studies for information related to the transplant procedures performed. The Company determines the appropriate accounting treatments for these payments depending on the nature of the payment and whether they are for distinct goods or services.

Contract Assets and Liabilities

The Company recognizes a receivable at the point in time at which it has an unconditional right to payment. Such receivables are not contract assets. Contract assets arise from unbilled amounts in customer arrangements when revenue recognized exceeds the amount billed to the customer and the Company’s right to payment is not just subject to the passage of time. The Company had no contract assets as of December 31, 2023 and 2022.

Contract liabilities represent the Company’s obligation to transfer goods or services to a customer for which it has received consideration (or the amount is due) from the customer. The Company has determined that its only contract liabilities are deferred revenue, which consists of amounts that have been invoiced but that have not been recognized as revenue.

Remaining Performance Obligations

The Company generally satisfies performance obligations within one year of the contract inception date, which amounts are included in deferred revenue and are not material.

Other Revenue Considerations

The Company only includes estimated variable amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. The Company does not assess whether promised goods or services are performance obligations if they are deemed immaterial in the context of the contract with the customer. Additionally, the Company does not assess whether a contract has a significant financing component if the expectation at contract inception is that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Revenue is reported net of taxes.

Distributors

The Company markets and sells its products primarily through its direct sales force, which sells its products to end customers globally. A small portion of the Company’s revenue is generated by sales to a limited number of distributors in Europe and Asia-Pacific. When the Company transacts with a distributor, its contractual arrangement is with the distributor and not with the end customer. Whether the Company transacts business with and receives the order from a distributor or directly from an end customer, its revenue recognition policy and resulting pattern of revenue recognition for the order are the same.

Research, Development and Clinical Trials Costs

Research, development and clinical trials expenses consist of costs incurred for research activities, product development, hardware and software engineering and clinical trial activities, including salaries and bonuses, stock-based compensation, employee benefits, facilities costs, laboratory supplies, depreciation, testing, regulatory, data management and consulting costs.

Research, development and clinical trials costs are expensed as incurred. Advance payments for goods or services to be received in the future for use in research, development and clinical trials activities are recorded as prepaid expenses. Such prepaid expenses are recognized as an expense when the related goods have been delivered or the related services have been performed, or when it is no longer expected that the goods will be delivered or the services rendered.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.

Foreign Currency Translation

The functional currency of each of the Company’s foreign subsidiaries is the currency of the local country. Assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars using the period-end exchange rates, and income and expense items are translated into U.S. dollars using average exchange rates in effect during each period. The effects of these foreign currency translation adjustments are included in accumulated other comprehensive loss, a separate component of stockholders’ equity.

The Company also incurs transaction gains and losses resulting from intercompany transactions as well as transactions with customers or vendors denominated in currencies other than the functional currency of the legal entity in which the transaction is recorded. Realized and unrealized foreign currency transaction gains (losses) are included in the consolidated statements of operations as a component of other income (expense) and totaled $0.3 million, ($1.3 million) and ($1.0 million) for the years ended December 31, 2023, 2022 and 2021, respectively.

Stock-based Compensation

Stock-Based Compensation

The Company accounts for stock-based awards granted to employees, non-employees and directors based on the fair value of the award on the date of grant. The fair value of option awards is measured using the Black-Scholes option-pricing model. The fair value of restricted common stock awards is measured based on the difference between market value of the Company’s common stock on date of grant and the purchase price (if any). Generally, the Company issues awards with only service-based vesting conditions. Compensation expense for those awards is recognized over the vesting period of the respective award using the straight-line method. The Company accounts for forfeitures as they occur and records compensation cost assuming all option holders will complete the requisite service period. When the unvested portion of an award is forfeited, the Company reverses compensation expense previously recognized in the period of the forfeiture.

The Company classifies stock-based compensation expense in its consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)

Comprehensive income (loss) includes net income (loss) as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only elements of other comprehensive income (loss) are foreign currency translation adjustments and unrealized gains (losses) on marketable securities.

Accumulated other comprehensive income (loss) on the consolidated balance sheets consists primarily of foreign currency translation adjustments. Accumulated other comprehensive income (loss) attributable to unrealized gains (losses) on marketable securities has not been significant.

Net Income (Loss) per Share

Basic net income (loss) per common share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock awards, using the treasury stock method, and outstanding convertible notes, using the if-converted method. For periods in which the Company reports a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders for each of the years ended December 31, 2023, 2022 and 2021.

The Company’s potential dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated above because including them would have had an anti-dilutive effect:


	As of December 31,
	2023		2022
Warrants to purchase common stock		14,440		14,440
Options to purchase common stock		3,289,051		3,288,791
Employee stock purchase plan		9,506		14,135
Restricted stock units		328,366		—
Restricted stock awards		9,606		24,315
Convertible senior notes		4,893,848		—
		8,544,817		3,341,681

Income Taxes

The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company's tax returns. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be realized and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by analyzing carryback capacity in periods with taxable income, reversal of existing taxable temporary differences and estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

Recently Issued Accounting Pronouncements

Recently issued accounting pronouncements

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently assessing the impact of the adoption of this guidance.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public entities, on an annual basis, to provide disclosure of specific categories in their tax rate reconciliations, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently assessing the impact of the adoption of this guidance.

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2021	Dec. 31, 2023	Dec. 31, 2022
Defined contribution plan, contribution amount		$ 1.4	$ 0.0
Recorded unconditional purchase commitment, minimum quantity required	$ 9.5
Recorded unconditional purchase commitment, maturity year and month	2029-12
Remaining purchase commitment		$ 7.0
First 3% of Compensation Contributed [Member]
Defined contribution plan, matching percentage of each employee's contribution		100.00%
100% Match [Member]
Defined contribution plan, percentage of matching contribution		3.00%
Excess of 3% to 5% of Compensation Contributed [Member]
Defined contribution plan, matching percentage of each employee's contribution		50.00%
Fifty Percent Match [Member] \| Additional Maximum [Member]
Defined contribution plan, percentage of matching contribution		2.00%

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Accrued Expenses And Other Current Liabilities [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	December 31,
	2023		2022
Accrued payroll and related expenses	$	20,300	$	9,812
Accrued transportation costs		4,381		2,581
Accrued research, development and clinical trials expenses		1,771		1,876
Accrued other		11,769		4,366
	$	38,221	$	18,635

Revenue - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Research development and clinical trials expenses	$ 0.9	$ 1.0	$ 2.1
Payment to customers related to use of aircraft	$ 1.1

Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

6. Goodwill and Intangible Assets

The carrying amount of goodwill was $12.0 million as of December 31, 2023 related to the Company’s acquisition of Summit. Goodwill is not amortized, but instead is reviewed for impairment at least annually or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. To date, the Company has had no impairments to goodwill.

Acquired intangible assets consisted of the following (in thousands):


			December 31, 2023
	Weighted Average Useful Life		Gross Amount		Accumulated Amortization		Carrying Value
	(in years)
Customer relationship		12	$	2,320	$	73	$	2,247
Other		12		110		3		107
			$	2,430	$	76	$	2,354

Amortization expense is recorded within selling, general and administrative expense. Amortization expense for the year ended December 31, 2023 was $0.1 million. Future amortization expense of the intangible assets as of December 31, 2023, is expected to be as follows (in thousands):


Year Ending December 31,
2024	$	203
2025		203
2026		203
2027		203
2028		203
Thereafter		1,339
	$	2,354

Related Party Transactions

12 Months Ended

Dec. 31, 2023

Related Party Transactions

15. Related Party Transactions

Employment of Dr. Amira Hassanein

Dr. Amira Hassanein, who serves as Product Director for the Company’s OCS Lung program, is the sister of Dr. Waleed Hassanein, the Company’s President, Chief Executive Officer and a member of the Company’s board of directors. The Company paid Dr. Amira Hassanein $0.4 million in total compensation in each of the years ended December 31, 2023, 2022 and 2021, respectively, for her services as an employee.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

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+ Details

Income Taxes - Schedule of Loss Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (27,038)	$ (36,416)	$ (44,321)
Foreign	367	251	142
Loss before income taxes	$ (26,671)	$ (36,165)	$ (44,179)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

11.

Income Taxes

Tax Provision Components

During the years ended December 31, 2023, 2022 and 2021, the Company recorded no income tax benefits for the net operating losses incurred or for the research and development tax credits generated in each year in the United States, due to the uncertainty regarding the realizability of these respective deferred tax assets. The Company generated income in the Netherlands for the years ended December 31, 2023, 2022 and 2021 and, accordingly, recorded a foreign income tax provision of less than $0.1 million, $0.1 million and less than $0.1 million for the years ended December 31, 2023, 2022 and 2021, respectively.

The Company recorded a tax benefit of $1.7 million for the release of a portion of its valuation allowance related to the net deferred tax liabilities recorded in purchase accounting during the year ended December 31, 2023. As part of the allocation of the purchase price of Summit, the Company recorded deferred tax liabilities for the differences between the fair value recognized in purchase accounting and the tax basis of property, plant and equipment and intangible assets. The net deferred tax liability is a source of income to support the recognition of a portion of its existing deferred tax assets. Therefore, the Company released the same amount of its valuation allowance. The Company maintains a valuation allowance on its overall net deferred tax asset as it deems it more likely than not that the net deferred tax asset will not be realized.

Loss Before Income Taxes

The domestic and foreign components of loss before income taxes were as follows (in thousands):


	Year Ended December 31,
	2023			2022			2021
United States	$	(27,038	)	$	(36,416	)	$	(44,321	)
Foreign		367			251			142
	$	(26,671	)	$	(36,165	)	$	(44,179	)

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	Year Ended December 31,
	2023			2022			2021
Federal statutory income tax rate		(21.0	)%		(21.0	)%		(21.0	)%
State taxes, net of federal benefit		(7.1	)%		(5.4	)%		(6.9	)%
Federal and state research and development tax credits		(10.2	)%		(5.4	)%		(2.4	)%
State deferred tax adjustment		(27.5	)%		—			—
Nondeductible items		1.2	%		0.7	%		0.1	%
Stock-based compensation expense		(5.7	)%		(3.5	)%		(3.3	)%
Deferred tax effect of change in state blended rate		(5.9	)%		16.2	%		(1.7	)%
Return to provision		(1.5	)%		2.6	%		1.1	%
Other		(0.1	)%		0.1	%		(0.2	)%
Change in deferred tax asset valuation allowance		71.6	%		15.8	%		34.3	%
Effective income tax rate		(6.2	)%		0.1	%		0.0	%

Net deferred tax assets consisted of the following (in thousands):


	December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	99,332		$	92,445
Capitalized research and development expense		14,062			8,109
Acquired in-process research and development expenses		7,275			—
Research and development tax credit carryforwards		16,195			13,565
Accrued expenses		5,657			2,994
Stock-based compensation expense		6,704			3,492
Lease liability		2,600			2,218
Section 163(j) interest		191			754
Other		400			483
Total deferred tax assets		152,416			124,060
Deferred tax liabilities:
Property, plant and equipment		(9,055	)		(885	)
Right-of-use assets		(1,721	)		(1,284	)
Intangible assets		(654	)		—
Total deferred tax liabilities		(11,430	)		(2,169	)
Valuation allowance		(140,986	)		(121,891	)
Net deferred tax assets	$	—		$	—

As of December 31, 2023, the Company had federal net operating loss carryforwards of $376.4 million, which may be available to offset future taxable income, of which $207.4 million of the total net operating loss carryforwards expire at various dates beginning in 2024, while the remaining $169.0 million do not expire but are limited in their usage to an annual deduction equal to 80% of annual taxable income. As of December 31, 2023, the Company had state net operating loss carryforwards of $328.8 million, which may be available to offset future taxable income and expire at various dates beginning in 2030. As of December 31, 2023, the Company also had U.S. federal and state research and development tax credit carryforwards of $10.7 million and $6.5 million, respectively, which may be available to offset future tax liabilities and begin to expire in 2024. As of December 31, 2023, the Company had no foreign net operating loss carryforwards.

Utilization of the U.S. federal and state net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Sections 382 and 383 of the Internal Revenue Code of 1986, and corresponding provisions of state law, due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income or tax liabilities. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period. The Company has not conducted a study to assess whether a change of control has occurred or whether there have been multiple changes of control since inception due to the significant complexity and cost associated with such a study. If the Company has experienced a change of control, as defined by Section 382, at any time since inception, utilization of the net operating loss carryforwards or research and development tax credit carryforwards would be subject to an annual limitation under Section 382, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term tax-exempt rate, and then could be subject to additional adjustments, as required. Any limitation may result in expiration of a portion of the net operating loss carryforwards or research and development tax credit carryforwards before utilization. Further, until a study is completed by the Company and any limitation is known, no amounts are being presented as an uncertain tax position.

As required by Accounting Standard Codification 740, management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards. Management has determined that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets and, as a result, a valuation allowance has been recorded.

As of December 31, 2023 and 2022, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts had been recognized in the Company’s consolidated statements of operations. The Company's policy is to record any interest or penalties related to income taxes as part of the income tax provision.

The Company generated research credits for the tax years ending after December 31, 2001 but has not conducted a study to document qualified activities. This study may result in an adjustment to the Company's research and development carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an unrecognized tax benefit for the year ended December 31, 2023. A full valuation allowance has been provided against the Company's research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the deferred tax asset established for the research credit carryforward and the valuation allowance.

The Company files income tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending federal or state tax examinations. The Company has open tax years subject to examination from fiscal year 2020 to present. To the extent that the Company has carryforward attributes, the tax years in which the attribute was generated may still be adjusted upon examination by federal, state or local tax authorities if they either have been or will be used in the future.

Changes in the valuation allowance for deferred tax assets during the year ended December 31, 2023 related primarily to current year federal and state net operating losses generated, acquired IPR&D and capitalized research and development costs. Changes in the valuation allowance for deferred tax assets during the year ended December 31, 2022 related primarily to the capitalization of research and development costs required under Section 174 and current year federal and state net operating losses generated, partially offset by a decrease in deferred tax assets related to state net operating loss carryforwards due to a change in the state effective tax rate. Changes in the valuation allowance for deferred tax assets during the year ended December 31, 2021 related primarily to the increase in net operating loss carryforwards in 2021. The changes in the valuation allowance were as follows (in thousands):


	Year Ended December 31,
	2023			2022			2021
Valuation allowance as of beginning of year	$	(121,891	)	$	(116,164	)	$	(101,029	)
Decreases recorded as benefit to income tax provision		—			—			—
Increases recorded to income tax provision		(19,095	)		(5,727	)		(15,135	)
Valuation allowance as of end of year	$	(140,986	)	$	(121,891	)	$	(116,164	)

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
-Name Accounting Standards Codification
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-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Leases - Summary of Operating Lease Liabilities on Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Current operating lease liabilities	$ 2,035	$ 1,444
Operating lease liabilities, net of current portion	7,707	$ 7,415
Total operating lease liabilities	$ 9,742

Inventory

12 Months Ended

Dec. 31, 2023

Inventory Disclosure [Abstract]

Inventory

4. Inventory

Inventory consisted of the following (in thousands):


	December 31,
	2023		2022
Raw materials	$	25,823	$	10,939
Work-in-process		3,806		1,876
Finished goods		14,606		7,790
	$	44,235	$	20,605

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Net loss	$ 25,028	$ 36,231	$ 44,215
Accumulated deficit	503,705	478,677
Cash	$ 394,812	$ 201,182

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ 0	$ 0	$ 0

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ (25,028)	$ (36,231)	$ (44,215)
Other comprehensive income (loss):
Foreign currency translation adjustment	26	(73)	(46)
Unrealized gains (losses) on marketable securities, net of tax of $0		36	(47)
Total other comprehensive income (loss)	26	(37)	(93)
Comprehensive loss	$ (25,002)	$ (36,268)	$ (44,308)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-SubTopic 10
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-Section 45
-Paragraph 1A
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

+ Details

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued payroll and related expenses	$ 20,300	$ 9,812
Accrued transportation costs	4,381	2,581
Accrued research, development and clinical trial expenses	1,771	1,876
Accrued other	11,769	4,366
Accrued expenses and other liabilities current	$ 38,221	$ 18,635

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred Stock, No Par Value
Preferred Stock, Shares Authorized	25,000,000	25,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, No Par Value
Common Stock, Shares Authorized	150,000,000	150,000,000
Common Stock, Shares, Issued	32,670,803	32,141,368
Common Stock, Shares, Outstanding	32,670,803	32,141,368

Nature of the Business and Basis of Presentation

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Nature of the Business and Basis of Presentation

TransMedics Group, Inc. (“TransMedics Group” and, together with its consolidated subsidiaries, the “Company”) was incorporated in the Commonwealth of Massachusetts in October 2018. TransMedics, Inc. (“TransMedics”), an operating company and wholly owned subsidiary of TransMedics Group, was incorporated in the State of Delaware in August 1998. The Company is a commercial-stage medical technology company transforming organ transplant therapy for end-stage organ failure patients across multiple disease states. The Company developed the Organ Care System (“OCS”) to replace a decades-old standard of care. The OCS represents a paradigm shift that transforms organ preservation for transplantation from a static state to a dynamic environment that enables new capabilities, including organ optimization and assessment. The Company’s OCS technology replicates many aspects of the organ’s natural living and functioning environment outside of the human body. The Company also developed its National OCS Program (“NOP”), an innovative turnkey solution to provide outsourced organ retrieval, OCS organ management and logistics services, to provide transplant programs in the United States with a more efficient process to procure donor organs with the OCS. Our logistics services include aviation transportation, ground transportation and other coordination activity.

On August 16, 2023, the Company acquired Summit Aviation, Inc. and Northside Property Group, LLC (together “Summit”). Summit was a charter flight operator based in Bozeman, Montana. The acquisition enabled TransMedics to add aviation transportation services to its NOP and become a comprehensive national provider of donor organ retrieval and delivery in the United States.

The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has incurred recurring annual losses since inception, including a net loss of $25.0 million for the year ended December 31, 2023. As of December 31, 2023, the Company had an accumulated deficit of $503.7 million. The Company believes that its existing cash of $394.8 million as of December 31, 2023 will be sufficient to fund its operations, capital expenditures, and debt service payments for at least the next 12 months following the filing of this Annual Report on Form 10-K. The Company may need to seek additional funding through equity financings, debt financings or strategic alliances. The Company may not be able to obtain financing on acceptable terms, or at all, and the terms of any financing may adversely affect the holdings or the rights of the Company’s shareholders. If the Company is unable to obtain funding when needed, the Company will be required to delay, reduce or eliminate some or all of its research and development programs, product expansion or commercialization efforts, or the Company may be unable to continue operations.

The Company is subject to risks and uncertainties common to companies in the medical device industry and of similar size, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, uncertainty of market acceptance of products, and the need to obtain additional financing to fund operations. Products currently under development will require additional research and development efforts, including additional clinical testing and regulatory approval, prior to commercialization. These efforts require additional capital, adequate personnel, infrastructure and extensive compliance-reporting capabilities. The Company’s research and development may not be successfully completed, adequate protection for the Company’s technology may not be obtained, the Company may not obtain necessary government regulatory approval on its expected timeline or at all, and approved products may not prove commercially viable. The Company operates in an environment of rapid change in technology and competition.

The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Equity

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Equity

Preferred Stock

As of December 31, 2023, the Company’s articles of organization authorized the Company to issue up to 25,000,000 shares of preferred stock, no par value per share, all of which is undesignated. The preferred stock will have such rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, as shall be determined by the Company’s boards of directors upon issuance.

Common Stock

As of December 31, 2023, the Company’s articles of organization authorized the Company to issue up to 150,000,000 shares of common stock, no par value per share. Each share of common stock is entitled to one vote on all matters submitted to a vote of the Company’s stockholders. The holders of common stock are entitled to receive dividends, if any, as may be declared by the board of directors, as described above. Through December 31, 2023, no dividends had been declared or paid.

Warrants

As of December 31, 2023, the Company had outstanding warrants to purchase 14,440 shares of common stock at an exercise price of $17.47 per share with an expiration date of May 6, 2024. In November 2022, warrants were exercised to purchase 50,000 shares of common stock at an exercise price of $8.75 per share for total proceeds of $0.4 million.

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-16

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Tax benefit	$ 1,700,000
Income tax benefits for research and development tax credits	$ 0	$ 0	$ 0
Foreign income tax provision		100,000
Operating loss carryforwards, limitations on use	These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income or tax liabilities. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period.
Unrecognized tax benefits	$ 0	0
Accrued interest or penalties related to uncertain tax positions	$ 0	$ 0
Earliest Tax Year [Member]
Income Taxes [Line Items]
Open Tax Year	2020
U.S. Federal [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 376,400,000
Operating loss carryforwards begin to expire	2024
U.S. Federal [Member] \| Expiration Beginning in 2023 [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 207,400,000
U.S. Federal [Member] \| Non-expirable [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 169,000,000
Percentage of annual deduction of taxable income	80.00%
State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 328,800,000
Operating loss carryforwards begin to expire	2030
Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 0
Research and Development Tax Credits [Member] \| U.S. Federal [Member]
Income Taxes [Line Items]
Tax credit carryforwards	$ 10,700,000
Tax credits carryforwards begin to expire	2024
Research and Development Tax Credits [Member] \| State [Member]
Income Taxes [Line Items]
Tax credit carryforwards	$ 6,500,000
Tax credits carryforwards begin to expire	2024
Maximum [Member]
Income Taxes [Line Items]
Foreign income tax provision	$ 100,000		$ 100,000

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2023	Jan. 31, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Registrant Name	TransMedics Group, Inc.
Entity Central Index Key	0001756262
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Financial Statement Error Correction [Flag]	false
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Public Float			$ 2,641
Entity Common Stock, Shares Outstanding		32,715,316
Entity File Number	001-38891
Entity Incorporation, State or Country Code	MA
Entity Tax Identification Number	83-2181531
Entity Address, Address Line One	200 Minuteman Road
Entity Address, City or Town	Andover
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01810
City Area Code	978
Local Phone Number	552-0900
ICFR Auditor Attestation Flag	true
Document Annual Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, No Par Value
Trading Symbol	TMDX
Security Exchange Name	NASDAQ
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Boston, Massachusetts
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Definitive Proxy Statement for its 2024 Annual Meeting of Stockholders scheduled to be held on May 23, 2024, which Definitive Proxy will be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of December 31, 2023, are incorporated by reference into Part II and Part III of this Form 10-K.

Stock-Based Compensation - Assumptions Used to Determine Grant Date Fair Value of Stock Options Granted (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Risk-free interest rate	4.15%	2.33%	0.90%
Expected term (in years)	6 years 10 days	6 years 10 days	6 years 10 days
Expected volatility	69.00%	59.00%	58.00%
Expected dividend yield	0.00%	0.00%	0.00%

Income Taxes - Reconciliation of U.S. Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	(21.00%)	(21.00%)	(21.00%)
State taxes, net of federal benefit	(7.10%)	(5.40%)	(6.90%)
Federal and state research and development tax credits	(10.20%)	(5.40%)	(2.40%)
State deferred tax adjustment	(27.50%)
Nondeductible items	1.20%	0.70%	0.10%
Stock-based compensation expense	(5.70%)	(3.50%)	(3.30%)
Deferred tax effect of change in state blended rate	(5.90%)	16.20%	(1.70%)
Return to provision	(1.50%)	2.60%	1.10%
Other	(0.10%)	0.10%	(0.20%)
Change in deferred tax asset valuation allowance	71.60%	15.80%	34.30%
Effective income tax rate	(6.20%)	0.10%	0.00%

Summary of Significant Accounting Policies - Schedule of Estimated Useful Life of Assets (Detail)	Dec. 31, 2023
Manufacturing Equipment [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
Transplant Aircraft [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	10 years
Flight School Aircraft [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
OCS Consoles [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Office Trade Show And Training Equipment [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Leasehold Improvements [Member] \| Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	15 years

Revenue - Schedule of Recognized Revenue Net of Payments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 241,623	$ 93,459	$ 30,262
Net product revenue [Member]
Disaggregation of Revenue [Line Items]
Gross product revenue from sales to customers	176,047	77,854	30,780
Less: Clinical trial payments	(22)	(1,380)	1,123
Total revenue	$ 176,069	$ 79,234	$ 29,657

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Schedule of Estimated Useful Life of Assets


		Estimated Useful Life
Transplant aircraft		10 years
Flight school aircraft		5 years
Manufacturing equipment		5 years
OCS Consoles		5 years
Computer equipment and software		3 years
Laboratory equipment		3 years
Office, trade show and training equipment		5 years
Leasehold improvements		Shorter of term of lease or 15 years

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated above because including them would have had an anti-dilutive effect:


	As of December 31,
	2023		2022
Warrants to purchase common stock		14,440		14,440
Options to purchase common stock		3,289,051		3,288,791
Employee stock purchase plan		9,506		14,135
Restricted stock units		328,366		—
Restricted stock awards		9,606		24,315
Convertible senior notes		4,893,848		—
		8,544,817		3,341,681

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Summary of Components of Lease Expense

The components of the Company’s lease expense under ASC 842 are as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Operating lease cost	$	1,692	$	1,353	$	1,353
Short-term lease cost		1,606		806		159
Variable lease cost		1,495		718		640
	$	4,793	$	2,877	$	2,152

Summary of Supplemental Disclosure of Cash Flow Information Related to Leases

Supplemental disclosure of cash flow information related to the leases were as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Cash paid for amounts included in the measurement of operating lease liabilities	$	2,246	$	1,948	$	1,901

Summary of Future Payments for Operating Lease Liabilities

Future payments for the Company’s operating lease liabilities as of December 31, 2023 are as follows (in thousands):


Year Ending December 31,
2024	$	2,638
2025		2,704
2026		2,771
2027		2,839
2028		25
Thereafter		610
Total future minimum lease payments		11,587
Less: imputed interest		(1,845	)
Total operating lease liabilities	$	9,742

Summary of Operating Lease Liabilities on Consolidated Balance Sheets

The following table represents operating lease liabilities on the consolidated balance sheets (in thousands):


	December 31, 2023
Current operating lease liabilities	$	2,035
Operating lease liabilities, net of current portion		7,707
Total operating lease liabilities	$	9,742

Acquisition of Summit - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Aug. 16, 2023	Dec. 31, 2023	Dec. 31, 2023
Business Acquisition [Line Items]
Upfront cash payment			$ 14,894,000
Tax benefit			$ 1,700,000
Goodwill adjustments		$ 300,000
Summit [Member]
Business Acquisition [Line Items]
Acquisition date	Aug. 16, 2023
Preliminary purchase consideration	$ 14,894,000
Upfront cash payment	18,000,000
Intangible assets	2,430,000
Goodwill resulting from the acquisition deductible for tax purposes	0
Tax benefit	1,700,000
Transaction costs	2,000,000
Summit [Member] \| Customer Relationship Asset [Member]
Business Acquisition [Line Items]
Intangible assets	$ 2,300,000
Estimated useful life	12 years

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Acquired Intangible Assets

Acquired intangible assets consisted of the following (in thousands):


			December 31, 2023
	Weighted Average Useful Life		Gross Amount		Accumulated Amortization		Carrying Value
	(in years)
Customer relationship		12	$	2,320	$	73	$	2,247
Other		12		110		3		107
			$	2,430	$	76	$	2,354

Future Amortization Expense of Intangible Assets

Future amortization expense of the intangible assets as of December 31, 2023, is expected to be as follows (in thousands):


Year Ending December 31,
2024	$	203
2025		203
2026		203
2027		203
2028		203
Thereafter		1,339
	$	2,354

Inventory - Schedule of Inventory, Current (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials	$ 25,823	$ 10,939
Work-in-process	3,806	1,876
Finished goods	14,606	7,790
Inventory, net	$ 44,235	$ 20,605

Long-Term Debt and Financing Arrangements - Long-term Debt - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Nov. 10, 2023	Jun. 23, 2023	May 11, 2023
Debt Instrument [Line Items]
Loss on extinguishment of debt			$ 575
Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 60,000	$ 60,000
Convertible Senior Notes [Member]
Debt Instrument [Line Items]
LIBOR rate						1.50%
Interest rate effective percentage		2.10%
Orbi Med [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ 600
Canadian Imperial Bank of Commerce [Member]
Debt Instrument [Line Items]
Interest rate effective percentage		7.30%
Average effective interest rate		7.70%	6.60%
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	60,000
Description of covenants		The financial covenants include, among other covenants, (x) a requirement to maintain a minimum liquidity amount of the greater of either (i) the consolidated adjusted EBITDA loss (or gain) for the trailing four month period (only if EBITDA is negative) and (ii) $10.0 million, and (y) a requirement to maintain total net revenue of at least 75% of the level set forth in the total revenue plan presented to CIBC
Minimum liquidity covenant amount		$ 10,000
Minimum percentage to maintain total net revenue set forth in total revenue plan presented		75.00%
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| Term Loan [Member] \| In Event Of Default [Member]
Debt Instrument [Line Items]
Increasing applicable margin		2.00%
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| Term Loan [Member] \| Upfront Fees and Other Costs [Member]
Debt Instrument [Line Items]
Debt instrument discount gross	$ 1,500
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| Interest Rate Option Two \| Term Loan [Member]
Debt Instrument [Line Items]
LIBOR rate	1.00%
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| Prior to 12 Months After Closing Date [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee percentage	2.00%
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| 12 to 24 Months After Closing Date [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee percentage	1.00%
Canadian Imperial Bank of Commerce [Member] \| Maximum [Member] \| Credit Agreement [Member] \| Aggregate All Acquisitions [Member]
Debt Instrument [Line Items]
Credit Agreement Acquisition Cash Consideration				$ 300,000	$ 150,000
Canadian Imperial Bank of Commerce [Member] \| Maximum [Member] \| Credit Agreement [Member] \| Individual Acquisition [Member]
Debt Instrument [Line Items]
Credit Agreement Acquisition Cash Consideration					$ 50,000
Canadian Imperial Bank of Commerce [Member] \| Term Secured Overnight Financing Rate [Member] \| Credit Agreement [Member] \| Interest Rate Option One [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Canadian Imperial Bank of Commerce [Member] \| Term Secured Overnight Financing Rate [Member] \| Minimum [Member] \| Credit Agreement [Member] \| Interest Rate Option One [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
LIBOR rate	1.50%
Canadian Imperial Bank of Commerce [Member] \| Prime Rate \| Minimum [Member] \| Credit Agreement [Member] \| Interest Rate Option Two \| Term Loan [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	4.00%
Canadian Imperial Bank of Commerce [Member] \| Amount Over Federal Funds Effective Rate [Member] \| Minimum [Member] \| Credit Agreement [Member] \| Interest Rate Option Two \| Term Loan [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%

Property, Plant and Equipment, Net

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment, Net

5. Property, Plant and Equipment, Net

Property, plant and equipment, net consisted of the following (in thousands):


	December 31,
	2023			2022
Transplant aircraft	$	141,855		$	—
Flight school aircraft		3,484			—
OCS Consoles		14,491			10,878
Manufacturing equipment		6,898			3,721
Computer equipment and software		3,021			2,064
Laboratory equipment		1,875			671
Office, trade show and training equipment		4,006			2,121
Leasehold improvements		13,354			12,415
Construction-in-progress		6,250			482
		195,234			32,352
Less: Accumulated depreciation and amortization		(21,293	)		(13,129	)
	$	173,941		$	19,223

During the years ended December 31, 2023, 2022 and 2021, total depreciation and amortization expense was $8.1 million, $3.5 million and $1.8 million, respectively. Construction-in-progress as of December 31, 2023 primarily relates to construction of a commercial aircraft hangar at Bozeman Yellowstone International Airport in Bozeman, Montana. Substantially all of the Company's property, plant and equipment are held in the United States.

Acquisition of Summit (Tables)

12 Months Ended

Dec. 31, 2023

Business Combinations [Abstract]

Summary of Assets Acquired and Liabilities Assumed

The following tables summarize the preliminary allocation of the purchase price (in thousands):


Assets Acquired and Liabilities Assumed:
Accounts receivable	$	2,089
Other current assets		1,040
Property, plant and equipment		5,922
Right-of-use asset		288
Intangible assets		2,430
Goodwill		11,990
Total assets acquired		23,759
Accounts payable and other current liabilities		(6,917	)
Deferred tax liabilities		(1,660	)
Operating lease liabilities		(288	)
Total allocation of purchase price consideration, net of cash acquired	$	14,894

Long-Term Debt and Financing Arrangements - Convertible Senior Notes - Additional Information (Detail)			12 Months Ended
	May 11, 2023 USD ($) TradingDays $ / shares shares	May 08, 2023	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Proceeds from Convertible Debt			$ 445,380,000
Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Estimated fair value of convertible senior notes			524,900,000
Conversion price per share \| $ / shares	$ 94
Premium percentage over closing price		32.50%
Maturity date of notes	Jun. 01, 2028
Interest expense, debt			$ 6,200,000
Percentage of cash coupon of notes and amortization of the debt issuance costs			1.50%
Proceeds from Convertible Debt	$ 393,300,000
Debt instrument, frequency of periodic payment	semiannually
Capped call transaction costs net	$ 52,100,000
Purchase discounts and other debt issuance costs	$ 14,600,000
Debt instrument, interest rate	1.50%
Debt instrument interest payable description			The Notes bear interest at a rate of 1.50% per year and interest is payable semiannually in arrears on June 1 and December 1 of each year.
Conversion of per principal amount of notes	$ 1,000
Average effective interest rate			2.10%
Convertible Senior Notes [Member] \| Used To Fund Capped Call Transactions [Member]
Debt Instrument [Line Items]
Proceeds from Convertible Debt	$ 52,100,000
Convertible Senior Notes [Member] \| Per One Thousand Dollars [Member]
Debt Instrument [Line Items]
Initial conversion rate shares of common stock \| shares	10.6388
Convertible Senior Notes [Member] \| Before March 1, 2028 [Member]
Debt Instrument [Line Items]
Conversion of per principal amount of notes	$ 1,000
Debt instrument, redemption period, end date	Mar. 01, 2028
Number of trading days \| TradingDays	5
Number of consecutive trading days \| TradingDays	10
Convertible Senior Notes [Member] \| Calendar Quarter Ending on September 30, 2023 but Before March 1, 2028 [Member]
Debt Instrument [Line Items]
Debt instrument, redemption period, start date	Sep. 30, 2023
Debt instrument, redemption period, end date	Mar. 01, 2028
Number of trading days \| TradingDays	20
Number of consecutive trading days \| TradingDays	30
Conversion price	130.00%
Convertible Senior Notes [Member] \| On or After June 8, 2026 [Member] \| Redeemable Debt [Member]
Debt Instrument [Line Items]
Number of trading days \| TradingDays	20
Number of consecutive trading days \| TradingDays	30
Conversion price	130.00%
Convertible Senior Notes [Member] \| Maximum [Member] \| Before March 1, 2028 [Member]
Debt Instrument [Line Items]
Conversion price	98.00%
Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount			$ 460,000,000
Private Placement [Member] \| Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount	$ 460,000,000

Revenue - Schedule of Net Revenue by Organ and Country (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

$ 241,623

$ 93,459

$ 30,262

OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

236,735

93,459

30,262

United States [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

221,347

84,038

21,861

All Other Countries [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

15,388

9,421

8,401

Lung revenue [Member] | United States [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

10,548

7,967

9,843

Lung revenue [Member] | All Other Countries [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

1,272

880

822

Heart revenue [Member] | United States [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

59,080

29,902

10,103

Heart revenue [Member] | All Other Countries [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

14,012

8,451

7,579

Liver revenue [Member] | United States [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

151,719

46,169

$ 1,915

Liver revenue [Member] | All Other Countries [Member] | OCS transplant revenue

Disaggregation Of Revenue [Line Items]

Total OCS transplant revenue

^[1],[2]

$ 104

$ 90

[1]	Revenue by country is categorized based on the location of the end customer. Total revenue includes product and service revenue.
[2]	Service revenue unrelated to OCS transplant, which was $4.9 million for the year December 31, 2023, is not included in this table.

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

- Definition

+ References

+ Details

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Use of Estimates

Risk of Concentrations of Credit, Significant Customers and Significant Suppliers

Deferred Financing Costs

Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents.

Restricted Cash

Accounts Receivable

Business Combinations

Transaction costs related to business combinations are expensed as incurred and are included in general and administrative expense in the consolidated statements of operations.

Asset Acquisitions

Goodwill and Acquired Intangible Assets

Property, Plant and Equipment


		Estimated Useful Life
Transplant aircraft		10 years
Flight school aircraft		5 years
Manufacturing equipment		5 years
OCS Consoles		5 years
Computer equipment and software		3 years
Laboratory equipment		3 years
Office, trade show and training equipment		5 years
Leasehold improvements		Shorter of term of lease or 15 years

Impairment of Long-Lived Assets

Software Development Costs

Inventory

Leases

Fair Value Measurements

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Segment Information

Product Warranties

Revenue Recognition

Payments Made to Customers

Contract Assets and Liabilities

Remaining Performance Obligations

The Company generally satisfies performance obligations within one year of the contract inception date, which amounts are included in deferred revenue and are not material.

Other Revenue Considerations

Distributors

Research, Development and Clinical Trials Costs

Patent Costs

Foreign Currency Translation

Stock-Based Compensation

Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)

Net Income (Loss) per Share


	As of December 31,
	2023		2022
Warrants to purchase common stock		14,440		14,440
Options to purchase common stock		3,289,051		3,288,791
Employee stock purchase plan		9,506		14,135
Restricted stock units		328,366		—
Restricted stock awards		9,606		24,315
Convertible senior notes		4,893,848		—
		8,544,817		3,341,681

Income Taxes

Recently issued accounting pronouncements

Leases - Summary of Components of Lease Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 1,692	$ 1,353	$ 1,353
Short-term lease cost	1,606	806	159
Variable lease cost	1,495	718	640
Lease expense	$ 4,793	$ 2,877	$ 2,152

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

13.

Commitments and Contingencies

401(k) Savings Plan

The Company has a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code. This plan covers substantially all employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. As of December 31, 2022, the Company had not made any contributions to the plan. Effective January 1, 2023, the Company instituted an employer matching program for the 401(k) Plan pursuant to which the Company will match 100% of the first 3% of each participating employee’s eligible compensation contributed to the plan and 50% of up to an additional 2% each participating employee’s eligible compensation contributed to the plan. For the year ended December 31, 2023, the Company recorded expense of $1.4 million related to these matching contributions.

Indemnification Agreements

In the ordinary course of business, the Company has agreed to defend and indemnify its customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets. The Company’s exposure under these indemnification provisions is generally limited to the total amount paid by the end-customer under the agreement. However, certain agreements include indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners, and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or services as directors or officers.

The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not currently aware of any indemnification claims and had not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31, 2023 and 2022.

Unconditional Purchase Commitment

In January 2021, the Company entered into an unconditional $9.5 million purchase commitment, in the ordinary course of business, for goods with specified annual minimum quantities to be purchased through December 2029. The contract is not cancellable without penalty. The remaining purchase commitment as of December 31, 2023 was $7.0 million.

Legal Proceedings

The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

Long-Term Debt and Financing Arrangements - Schedule of Long-term Debt Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Long-term debt, net of discount and current portion	$ 59,064	$ 58,696
Term Loan Member
Debt Instrument [Line Items]
Principal amount	60,000	60,000
Net of current portion	60,000	60,000
Debt discount, net of accretion	(936)	(1,304)
Long-term debt, net of discount and current portion	$ 59,064	$ 58,696

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Stockholders' Equity Note [Abstract]

Assumptions Used to Determine Grant Date Fair Value of Stock Options Granted

The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to employees and directors:


	Year Ended December 31,
	2023			2022			2021
Risk-free interest rate		4.15	%		2.33	%		0.90	%
Expected term (in years)		6.03			6.03			6.03
Expected volatility		69	%		59	%		58	%
Expected dividend yield		0	%		0	%		0	%

Summary of Stock Option Activity

The following table summarizes the Company’s option activity since December 31, 2022:


	Number of Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2022		3,288,791		$	21.56		7.86	$	132,076
Granted		639,045			64.37
Exercised		(493,935	)		12.46
Forfeited		(143,913	)		34.14
Expired		(937	)		30.57
Outstanding as of December 31, 2023		3,289,051		$	30.69		7.52	$	159,343
Vested and expected to vest as of December 31, 2023		3,289,051		$	30.69		7.52	$	159,343
Options exercisable as of December 31, 2023		1,920,240		$	23.78		6.84	$	105,898

Summary of Restricted Common Stock Activity

The following table summarizes the Company's restricted common stock activity since December 31, 2022:


	Shares			Weighted Average Grant-Date Fair Value
Unvested restricted common stock as of December 31, 2022		24,315		$	28.79
Issued		10,304			72.75
Vested		(24,315	)		28.79
Forfeited		(698	)		71.60
Unvested restricted common stock as of December 31, 2023		9,606		$	72.83

The following table summarizes the Company's restricted common stock unit activity since December 31, 2022:


	Shares			Weighted Average Grant-Date Fair Value
Unvested restricted stock units as of December 31, 2022		—		$	—
Granted		357,594			63.74
Vested		—			—
Forfeited		(29,228	)		56.53
Unvested restricted stock units as of December 31, 2023		328,366		$	64.38

Schedule of Stock-Based Compensation Expense

The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations (in thousands):


	Year Ended December 31,
	2023		2022		2021
Cost of revenue	$	438	$	125	$	72
Research, development and clinical trials expenses		2,823		1,465		1,114
Selling, general and administrative expenses		16,530		8,731		5,692
	$	19,791	$	10,321	$	6,878

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Warrants to purchase common stock	8,544,817	3,341,681
Warrants to purchase common stock [Member]
Warrants to purchase common stock	14,440	14,440
Options to purchase common stock [Member]
Warrants to purchase common stock	3,289,051	3,288,791
Employee stock purchase plan [Member]
Warrants to purchase common stock	9,506	14,135
Restricted stock units [Member]
Warrants to purchase common stock	328,366
Restricted stock awards [Member]
Warrants to purchase common stock	9,606	24,315
Convertible senior notes [Member]
Warrants to purchase common stock	4,893,848

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Loss Before Income Taxes

Loss Before Income Taxes

The domestic and foreign components of loss before income taxes were as follows (in thousands):


	Year Ended December 31,
	2023			2022			2021
United States	$	(27,038	)	$	(36,416	)	$	(44,321	)
Foreign		367			251			142
	$	(26,671	)	$	(36,165	)	$	(44,179	)

Reconciliation of U.S. Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	Year Ended December 31,
	2023			2022			2021
Federal statutory income tax rate		(21.0	)%		(21.0	)%		(21.0	)%
State taxes, net of federal benefit		(7.1	)%		(5.4	)%		(6.9	)%
Federal and state research and development tax credits		(10.2	)%		(5.4	)%		(2.4	)%
State deferred tax adjustment		(27.5	)%		—			—
Nondeductible items		1.2	%		0.7	%		0.1	%
Stock-based compensation expense		(5.7	)%		(3.5	)%		(3.3	)%
Deferred tax effect of change in state blended rate		(5.9	)%		16.2	%		(1.7	)%
Return to provision		(1.5	)%		2.6	%		1.1	%
Other		(0.1	)%		0.1	%		(0.2	)%
Change in deferred tax asset valuation allowance		71.6	%		15.8	%		34.3	%
Effective income tax rate		(6.2	)%		0.1	%		0.0	%

Schedule of Net deferred Tax Assets

Net deferred tax assets consisted of the following (in thousands):


	December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	99,332		$	92,445
Capitalized research and development expense		14,062			8,109
Acquired in-process research and development expenses		7,275			—
Research and development tax credit carryforwards		16,195			13,565
Accrued expenses		5,657			2,994
Stock-based compensation expense		6,704			3,492
Lease liability		2,600			2,218
Section 163(j) interest		191			754
Other		400			483
Total deferred tax assets		152,416			124,060
Deferred tax liabilities:
Property, plant and equipment		(9,055	)		(885	)
Right-of-use assets		(1,721	)		(1,284	)
Intangible assets		(654	)		—
Total deferred tax liabilities		(11,430	)		(2,169	)
Valuation allowance		(140,986	)		(121,891	)
Net deferred tax assets	$	—		$	—

Summary Changes in the Valuation Allowance for Deferred Tax Assets

Changes in the valuation allowance for deferred tax assets during the year ended December 31, 2022 related primarily to the capitalization of research and development costs required under Section 174 and current year federal and state net operating losses generated, partially offset by a decrease in deferred tax assets related to state net operating loss carryforwards due to a change in the state effective tax rate. Changes in the valuation allowance for deferred tax assets during the year ended December 31, 2021 related primarily to the increase in net operating loss carryforwards in 2021. The changes in the valuation allowance were as follows (in thousands):


	Year Ended December 31,
	2023			2022			2021
Valuation allowance as of beginning of year	$	(121,891	)	$	(116,164	)	$	(101,029	)
Decreases recorded as benefit to income tax provision		—			—			—
Increases recorded to income tax provision		(19,095	)		(5,727	)		(15,135	)
Valuation allowance as of end of year	$	(140,986	)	$	(121,891	)	$	(116,164	)

Leases - Summary of Future Payments for Operating Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 2,638
2025	2,704
2026	2,771
2027	2,839
2028	25
Thereafter	610
Total future minimum lease payments	11,587
Less: imputed interest	(1,845)
Lease liabilities	$ 9,742

Subsequent Events - Additional Information (Details) - Subsequent Event [Member] $ in Millions	2 Months Ended
	Feb. 27, 2024 USD ($) Aircraft Seller
Subsequent Event [Line Items]
Number of fixed wing aircraft acquired \| Aircraft	2
Number of fixed wing aircraft sellers \| Seller	2
Purchase price of fixed wing aircrafts \| $	$ 26.6

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allocated Share-based Compensation Expense	$ 19,791	$ 10,321	$ 6,878
Cost of revenue [Member]
Allocated Share-based Compensation Expense	438	125	72
Research, development and clinical trials expenses [Member]
Allocated Share-based Compensation Expense	2,823	1,465	1,114
Selling, general and administrative expenses [Member]
Allocated Share-based Compensation Expense	$ 16,530	$ 8,731	$ 5,692

Insider Trading Arrangements

3 Months Ended

Dec. 31, 2023

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

During our fiscal quarter ended December 31, 2023, one of our directors entered into a contract, instruction or written plan for the purchase or sale of our securities that is intended to satisfy the conditions specified in Rule 10b5-1(c) under the Exchange Act for an affirmative defense against liability for trading in securities on the basis of material nonpublic information. We refer to these contracts, instructions, and written plans as “Rule 10b5-1 trading plans” and each one as a “Rule 10b5-1 trading plan.”

We describe the material terms of this Rule 10b5-1 trading plan in the table below.

Rule 10b5-1 Trading Plans

       
      Maximum

       
      Number

       
      of Securities to

       
      Scheduled

      be Purchased or

       
      Action

      Commencement

      Termination

      Sold Pursuant to

      Covers

       
      and Date

      of Trading

      of Trading

      Security

      the Rule 10b5-1

      Purchase

      Director/Officer

      of Action

      Period

      Period (1)

      Covered

      Trading Plan (2)

      Or Sale

James Tobin, 
Chairman of the Board of Directors

Adoption
21-Nov-23

20-Feb-24

30-Dec-24

Common Stock

40,445

Sale

(1)

The plan is subject to earlier termination under certain circumstances specified in the plan, including upon the sale or purchase (as applicable) of all shares subject to the plan and upon either party to a plan giving notice of termination within the time prescribed under the plan.

(2)

Subject to adjustments for stock splits, stock combinations, stock dividends and other similar changes to our common stock.

Name

James Tobin

Title

Chairman of the Board of Directors

Rule 10b5-1 Arrangement Adopted

true

Adoption Date

21-Nov-23

Rule 10b5-1 Arrangement Terminated

true

Termination Date

30-Dec-24

Arrangement Duration

315 days

Aggregate Available

40,445

Long-Term Debt and Financing Arrangements

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Long-Term Debt and Financing Arrangements

Convertible Senior Notes

Convertible senior notes consisted of the following (in thousands):


	December 31, 2023
Principal amount of convertible senior notes	$	460,000
Less: Current portion of convertible senior notes		—
Convertible senior notes, net of current portion		460,000
Debt discount, net of accretion		(12,860	)
Convertible senior notes, net of discount and current portion	$	447,140

As of December 31, 2023, the estimated fair value of the Notes was $524.9 million. The fair value was determined based on the quoted price of the last trade of the Notes prior to the end of the reporting period in an inactive market, which is considered as Level 2 in the fair value hierarchy.

On May 11, 2023, the Company issued $460.0 million aggregate principal amount of the Notes, in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act, pursuant to an indenture dated May 11, 2023, by and between the Company and U.S. Bank Trust Company, National Association (the “Indenture”).

The initial conversion price of the Notes is approximately $94.00 per share of common stock, which represents a premium of approximately 32.5% over the closing price of the Company’s common stock on May 8, 2023. The Notes will mature on June 1, 2028, unless earlier repurchased, redeemed or converted. The Company used $52.1 million of the proceeds from the sale of the Notes to fund the cost of entering into capped call transactions, described below. The proceeds from the issuance of the Notes were approximately $393.3 million, net of capped call transaction costs of $52.1 million and initial purchaser discounts and other debt issuance costs totaling $14.6 million.

The Notes bear interest at a rate of 1.50% per year and interest is payable semiannually in arrears on June 1 and December 1 of each year. The initial conversion rate is 10.6388 shares of common stock per $1,000 principal amount of the Notes, which represents an initial conversion price of approximately $94.00 per share of common stock. The conversion rate and conversion price are subject to customary adjustments upon the occurrence of certain events as described in the Indenture.

Before March 1, 2028, noteholders have the right to convert their Notes only upon the occurrence of certain events, including certain corporate events, and during the five business days immediately after any ten consecutive trading days in which the trading price per $1,000 principal amount of Notes is less than ninety eight percent (98%) of the as converted value. Additionally, the noteholder can convert their Notes during any calendar quarter (and only during such calendar quarter), commencing after the calendar quarter ending on September 30, 2023 but before March 1, 2028, provided the last reported sale price of the common stock for at least 20 trading days is greater than or equal to 130% of the conversion price during the 30 consecutive trading days ending on the last trading day of a calendar quarter. From and after March 1, 2028, noteholders may convert their Notes at any time at their election until the close of business on the second scheduled trading day immediately before the maturity date. The Company has the right to elect to settle conversions either in cash, shares or in a combination of cash and shares of its common stock.

Prior to June 8, 2026, the Notes will not be redeemable. On or after June 8, 2026, the Company may redeem for cash all or any portion of the Notes (subject to the partial redemption limitation set forth in the Indenture), at its option, if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption. In addition, calling any Note for redemption will constitute a “Make-Whole Fundamental Change” (as defined in the Indenture) with respect to that Note, in which case the conversion rate applicable to the conversion of that Note will be increased in certain circumstances if it is converted after it is called for redemption.

The Company accounts for the Notes as a single liability in accordance with ASC 470-20 as the Company concluded that embedded conversion features within the Notes do not meet the requirements for bifurcation. Initial purchaser discounts and other debt issuance costs related to the Notes totaling $14.6 million were recorded by the Company as a debt discount. The debt discount is reflected as a reduction of the carrying value of the Notes on the Company’s consolidated balance sheets and is being accreted to interest expense over the term of the Notes using the effective interest method. During the year ended December 31, 2023, the Company recognized $6.2 million in interest expense related to the 1.50% cash coupon of the Notes and amortization of the debt issuance costs. During the year ended December 31, 2023, the effective interest rate on the outstanding Notes was approximately 2.1%.

Capped Call Transactions

In connection with the offering of the Notes, the Company entered into privately negotiated capped call transactions (the “Capped Calls”) with certain financial institution counterparties (the “Option Counterparties”). The Capped Calls are generally intended to reduce or offset the potential dilution to the common stock upon any conversion of the Notes with such reduction or offset, as the case may be, subject to a cap based on the cap price. For accounting purposes, the Capped Calls are separate transactions, and not part of the terms of the Notes. The Capped Calls are recorded in stockholders’ equity and are not accounted for as derivatives. The cost of $52.1 million incurred to purchase the Capped Calls were recorded as a reduction to common stock on the accompanying consolidated balance sheets.

Each of the Capped Calls has an initial strike price of approximately $94.00 per share, subject to certain adjustments, which corresponds to the initial conversion price of the Notes. The Capped Calls have an initial cap price of $141.88 per share, subject to certain adjustments. The Capped Calls cover, subject to anti-dilution adjustments, approximately 4,893,848 shares of the Company’s common stock, which is the same number of shares of the Company’s common stock initially underlying the Notes. The Capped Calls are subject to automatic exercise over a 40 trading day period commencing on April 3, 2028, subject to earlier termination under certain circumstances.

Long-term debt

Long-term debt consisted of the following (in thousands):


	December 31,
	2023			2022
Principal amount of long-term debt	$	60,000		$	60,000
Less: Current portion of long-term debt		—			—
Long-term debt, net of current portion		60,000			60,000
Debt discount, net of accretion		(936	)		(1,304	)
Long-term debt, net of discount and current portion	$	59,064		$	58,696

Canadian Imperial Bank of Commerce Credit Agreement

In July 2022, the Company entered into a credit agreement with Canadian Imperial Bank of Commerce (“CIBC”), as amended by the First Amendment to Credit Agreement, dated as of May 8, 2023, by and among the Company and CIBC (the “First Amendment”), the Second Amendment to Credit Agreement, dated as of June 23, 2023, by and among the Company, and CIBC (the “Second Amendment”), the Third Amendment to Credit Agreement, dated as of November 9, 2023, by and among the Company, and CIBC (the “Third Amendment”) (as amended, the “CIBC Credit Agreement”), pursuant to which the Company borrowed $60.0 million. In connection with the CIBC Credit Agreement, the Company repaid all amounts due under its previously outstanding credit agreement and recorded a loss on extinguishment of debt of $0.6 million during 2022, which amount was classified as other expense in the consolidated statements of operations.

On May 8, 2023, the Company entered into the First Amendment, which among other items, allowed for the issuance of the Notes and capped call transactions. On June 23, 2023, the Company entered into the Second Amendment, which among other items, permits the Company to make acquisitions of equity or assets of another entity, subject to the conditions under the Second Amendment, including acquisitions, without further consent of CIBC, up to a maximum amount of $50.0 million for the cash payable in connection with an individual acquisition and a maximum amount in aggregate of $150.0 million for the total cash consideration payable for all acquisitions made by the Company on or after June 23, 2023. The definition of consolidated adjusted EBITDA was also amended by the Second Amendment to add a provision for the pro forma effect of any acquisitions that occur during the period. Additionally, pursuant to the Second Amendment, the parties agreed to extend the start of the principal repayment period to July 31, 2026, on which date the Company is obligated to begin repayment of the term loans in equal monthly installments until the maturity date in July 2027. On November 9, 2023, the Company entered into the Third Amendment, which, among other items, permits the Company to make acquisitions of equity or assets of another entity, subject to the conditions under the Third Amendment, without further consent of CIBC, for cash consideration in a maximum aggregate amount of $300.0 million for all such acquisitions made by the Company on or after November 9, 2023.

Borrowings under the CIBC Credit Agreement bear interest at an annual rate equal to either, at the Company’s option, (i) the secured overnight financing rate for an interest period selected by the Company, subject to a minimum of 1.50%, plus 2.0% or (ii) 1.0% plus the higher of a) the prime rate subject to a minimum of 4.0% or b) the Federal Funds Effective Rate, plus 0.5%. At the Company’s option, the Company may prepay borrowings outstanding under the CIBC Credit Agreement, subject to a prepayment fee of 2.0% of outstanding borrowings if paid prior to 12 months after the closing date, and 1.0% if paid on or after 12 months after the closing date but prior to 24 months after the closing date.

In connection with entering into the CIBC Credit Agreement, the Company paid upfront fees and other costs of $1.5 million, which were recorded by the Company as a debt discount. The debt discount is reflected as a reduction of the carrying value of long-term debt on the Company’s consolidated balance sheets and is being accreted to interest expense over the term of the CIBC Credit Agreement using the effective interest method.

All obligations under the CIBC Credit Agreement are guaranteed by the Company and each of its material subsidiaries. All obligations of the Company and each guarantor are secured by substantially all of the Company’s and each guarantor’s assets, including their intellectual property, subject to certain exceptions. Under the CIBC Credit Agreement, the Company has agreed to customary representations and warranties, events of default and certain affirmative and negative covenants to which it will remain subject until maturity. The financial covenants include, among other covenants, (x) a requirement to maintain a minimum liquidity amount of the greater of either (i) the consolidated adjusted EBITDA loss (or gain) for the trailing four month period (only if EBITDA is negative) and (ii) $10.0 million, and (y) a requirement to maintain total net revenue of at least 75% of the level set forth in the total revenue plan presented to CIBC. As discussed above, the definition of consolidated adjusted EBITDA was amended to include the pro forma effect of acquisitions. The obligations under the CIBC Credit Agreement are subject to acceleration upon the occurrence of specified events of default, including payment default, change in control, bankruptcy, insolvency, certain defaults under other material debt, certain events with respect to governmental approvals (if such events could cause a material adverse change in the Company’s business), failure to comply with certain covenants and a material adverse change in the Company’s business, operations or financial condition. As of December 31, 2023, the Company was in compliance with all financial covenants of the CIBC Credit Agreement.

During the continuance of an event of default, the interest rate per annum will be equal to the rate that would have otherwise been applicable at the time of the event of default plus 2.0%. If an event of default (other than certain events of bankruptcy or insolvency) occurs and is continuing, CIBC may declare all or any portion of the outstanding principal amount of the borrowings plus accrued and unpaid interest to be due and payable. Upon the occurrence of certain events of bankruptcy or insolvency, all of the outstanding principal amount of the borrowings plus accrued and unpaid interest will automatically become due and payable. In addition, the Company may be required to prepay outstanding borrowings, subject to certain exceptions, with portions of net cash proceeds of certain asset sales and certain casualty and condemnation events.

The Company assessed all terms and features of the CIBC Credit Agreement in order to identify any potential embedded features that would require bifurcation. As part of this analysis, the Company assessed the economic characteristics and risks of the debt. The Company determined that all features of the CIBC Credit Agreement are either clearly and closely associated with a debt host or have a de minimis fair value and, as such, do not require separate accounting as a derivative liability.

As of December 31, 2023, the stated interest rate applicable to borrowings under the CIBC Credit Agreement was 7.3%. During the years ended December 31, 2023 and 2022, the weighted average effective interest rate on outstanding borrowings under the CIBC Credit Agreement was approximately 7.7% and 6.6%, respectively.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Stockholders' Equity Note [Abstract]

Stock-Based Compensation

10.

Stock-Based Compensation

2019 Stock Incentive Plan

The 2019 Stock Incentive Plan (the “2019 Plan”) provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock, restricted stock units, unrestricted stock, unrestricted stock units, and other stock-based awards to employees, directors, and consultants of the Company and its subsidiaries. The number of shares of common stock of TransMedics Group initially available for issuance under the 2019 Plan was 3,428,571 shares, plus the number of shares underlying awards under the previously outstanding 2014 Stock Incentive Plan (the “2014 Plan”), not to exceed 1,595,189 shares, that expire or are terminated, surrendered, or cancelled without the delivery of shares, are forfeited to or repurchased by TransMedics Group or otherwise become available again for grant. Since the effectiveness of the Company’s 2019 Plan in April 2019, no awards have been made or will be made under the 2014 Plan.

Shares withheld in payment of the exercise or purchase price of an award or in satisfaction of tax withholding requirements, and the shares covered by a stock appreciation right for which any portion is settled in stock, will reduce the number of shares available for issuance under the 2019 Plan. In addition, the number of shares available for issuance under the 2019 Plan (i) will not be increased by any shares delivered under the 2019 Plan that are subsequently repurchased using proceeds directly attributable to stock option exercises and (ii) will not be reduced by any awards that are settled in cash or that expire, become unexercisable, terminate or are forfeited to or repurchased by TransMedics Group without the issuance of stock under the 2019 Plan. On May 25, 2023, the shareholders of the Company approved the Amended and Restated TransMedics Group, Inc. 2019 Stock Incentive Plan (the “Amended Plan”) to among other things, (i) increase the number of shares of the Company’s common stock available for issuance thereunder by 1,000,000 shares, (ii) prohibit the payment of dividend or dividend equivalents on a current basis with respect to unvested awards, (iii) extend the expiration date of the Amended Plan until June 1, 2033 and (iv) increase the annual limits on non-employee director compensation. As of December 31, 2023, 1,359,742 shares of common stock were available for issuance under the Amended Plan.

2021 Inducement Plan

In August 2021, the Company’s board of directors approved the TransMedics Group, Inc. Inducement Plan (the “Inducement Plan”). Pursuant to the terms of the Inducement Plan, the Company may grant nonqualified stock options, stock appreciation rights, restricted stock, unrestricted stock, restricted stock unit awards and performance awards to individuals who were not previously employees or directors of the Company or individuals returning to employment after a bona fide period of non-employment with the Company. A total of 1,000,000 shares of the Company’s common stock were initially available for issuance under the Inducement Plan. On November 2, 2023, the Company's board of directors approved an increase of 500,000 to shares available under the Inducement Plan. As of December 31, 2023, 607,366 shares of common stock remained available for issuance under the Inducement Plan.

Awards granted under the 2019 Plan and Inducement Plan vest over periods determined by the board of directors and expire no longer than ten years from the date of the grant. The exercise price for stock options granted is not less than the fair value of common shares based on quoted market prices.

2019 Employee Stock Purchase Plan

Pursuant to the Company’s 2019 Employee Stock Purchase Plan (the “2019 ESPP”), certain employees of the Company are eligible to purchase common stock of the Company at a reduced price during offering periods. The 2019 ESPP permits participants to purchase common stock using funds contributed through payroll deductions, subject to the limitations set forth in the Internal Revenue Code, at a purchase price of 85% of the lower of the closing price of the Company’s common stock on the first trading day of the offering period or the closing price on the applicable purchase date, which is the final trading day of the applicable offering period. A total of 371,142 shares of common stock of TransMedics Group were initially reserved for issuance under the 2019 ESPP. During the year ended December 31, 2023, 25,894 shares were issued under the 2019 ESPP and as of December 31, 2023, 264,559 shares remained available for issuance.

Stock Option Valuation

The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. Because there had been no public market for the Company's common stock prior to the Company's initial public offering, there is limited Company-specific historical and implied volatility data. Accordingly, the Company bases its estimates of expected volatility on a combination of the Company's own historical volatility and historical volatility of a group of publicly-traded companies with similar characteristics to itself. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.


	Year Ended December 31,
	2023			2022			2021
Risk-free interest rate		4.15	%		2.33	%		0.90	%
Expected term (in years)		6.03			6.03			6.03
Expected volatility		69	%		59	%		58	%
Expected dividend yield		0	%		0	%		0	%

The following table summarizes the Company’s option activity since December 31, 2022:


	Number of Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2022		3,288,791		$	21.56		7.86	$	132,076
Granted		639,045			64.37
Exercised		(493,935	)		12.46
Forfeited		(143,913	)		34.14
Expired		(937	)		30.57
Outstanding as of December 31, 2023		3,289,051		$	30.69		7.52	$	159,343
Vested and expected to vest as of December 31, 2023		3,289,051		$	30.69		7.52	$	159,343
Options exercisable as of December 31, 2023		1,920,240		$	23.78		6.84	$	105,898

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2023, 2022 and 2021, was $31.0 million, $15.0 million and $16.3 million, respectively. The weighted average grant-date fair

value of stock options granted during the years ended December 31, 2023, 2022 and 2021 was $41.75 per share, $11.32 per share and $18.63 per share, respectively.

The Company has not granted any stock-based awards with performance-based vesting conditions.

Restricted Common Stock

Shares of unvested restricted common stock may not be sold or transferred by the holder. If the holder’s service to the Company and its affiliates ceases for any reason, unvested shares of restricted common stock held by these individuals will immediately be forfeited for no consideration, as provided in the individual restricted stock agreements.

The following table summarizes the Company's restricted common stock activity since December 31, 2022:


	Shares			Weighted Average Grant-Date Fair Value
Unvested restricted common stock as of December 31, 2022		24,315		$	28.79
Issued		10,304			72.75
Vested		(24,315	)		28.79
Forfeited		(698	)		71.60
Unvested restricted common stock as of December 31, 2023		9,606		$	72.83

The aggregate fair value of restricted stock that vested during the year ended December 31, 2023 was $1.7 million. There was no restricted stock vesting during the years ended December 31, 2022 or 2021. The Company granted restricted common stock during the year ended December 31, 2022 with a weighted average grant-date fair value of $28.74 per share. The Company did not grant restricted common stock during the year ended December 31, 2021.

Restricted Common Stock Units

The following table summarizes the Company's restricted common stock unit activity since December 31, 2022:


	Shares			Weighted Average Grant-Date Fair Value
Unvested restricted stock units as of December 31, 2022		—		$	—
Granted		357,594			63.74
Vested		—			—
Forfeited		(29,228	)		56.53
Unvested restricted stock units as of December 31, 2023		328,366		$	64.38

The Company did not grant restricted common stock units during the years ended December 31, 2022 or 2021.

Stock-Based Compensation

The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations (in thousands):


	Year Ended December 31,
	2023		2022		2021
Cost of revenue	$	438	$	125	$	72
Research, development and clinical trials expenses		2,823		1,465		1,114
Selling, general and administrative expenses		16,530		8,731		5,692
	$	19,791	$	10,321	$	6,878

As of December 31, 2023, total unrecognized compensation cost related to unvested share-based awards was $48.6 million, which is expected to be recognized over a weighted-average period of 2.4 years.

Leases - Additional Information (Detail)	12 Months Ended
Leases - Additional Information (Detail)	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lease expiration month and year	Dec. 31, 2027
Lessee, operating lease, existence of option to extend [true false]	true
Lessee operating lease description	two noncancelable leases that expire in December 2027 and include a lease incentive, fixed payment escalations, and rent holidays. The leases include an option to renew for an additional five years.
Lessee, operating lease, renewal term	5 years
Lease base rent annual increase	2.50%
Operating lease, weighted-average remaining lease term	4 years 8 months 12 days	5 years
Operating lease, weighted-average discount rate	6.90%	6.70%
Summit [Member]
Lessee, Lease, Description [Line Items]
Lessee, operating lease, existence of option to extend [true false]	true
Lessee, operating lease, renewal term	10 years
Lessee, operating lease term	20 years

Segment Reporting and Geographic Data - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 Segment
Segment Reporting [Abstract]
Number of operating segments	1

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Letter Segment	Dec. 31, 2022 USD ($) Letter	Dec. 31, 2021 USD ($)
Letters of credit outstanding	$ 500,000	$ 500,000
Number of letters of credit maintained \| Letter	2	2
Restricted cash non-current	$ 500,000	$ 500,000
Allowance for credit losses	0	0
Provisions for credit losses	0	0	$ 0
Write off accounts receivable balances	0		0
Impairment losses on long-lived assets	0	0	0
Provision for loss on contracts	$ 0
Number of operating segments \| Segment	1
Term of product warranties	1 year
Product warranty description	The Company provides a one-year warranty on its OCS Consoles and disposable sets and replaces or repairs any OCS Console or disposable set that does not function in accordance with the product specifications
Contract with customer, asset, after allowance for credit loss	$ 0	0
Acquired in-process research and development expenses	27,212,000
Acquired in-process research and development expenses	$ 27,212,000
Transplant Aircraft and Flight School Aircraft [Member]
Salvage value percentage	50.00%
Convertible Senior Notes Due 2028 [Member]
Debt Instrument, Interest Rate, Stated Percentage	1.50%
Bridge to Life Ltd [Member]
Acquisition, date	Aug. 02, 2023
Other Income (Expense) [Member]
Foreign currency transaction gains (losses)	$ 300,000	(1,300,000)	(1,000,000)
Maximum [Member]
Write off accounts receivable balances		100,000
Product warranty accrual	$ 100,000	100,000
Performance obligations satisfaction period	1 year
Internal Use [Member]
Capitalized software development costs	$ 0	0	0
Sold to Customers [Member]
Capitalized software development costs	0	$ 0	$ 0
IPR&D [Member] \| Bridge to Life Ltd [Member]
Acquired in-process research and development expenses	$ 27,200,000
Customer Concentration Risk [Member] \| Revenue [Member] \| Significant Customer Benchmark [Member] \| Minimum [Member]
Concentration risk percentage	10.00%
Customer Concentration Risk [Member] \| Revenue [Member] \| Customer One [Member]
Concentration risk percentage		14.00%	11.00%
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Significant Customer Benchmark [Member] \| Minimum [Member]
Concentration risk percentage	10.00%	10.00%

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Statement of Cash Flows [Abstract]
Convertible senior notes, issuance costs paid	$ 14,620

Goodwill and Intangible Assets - Schedule of Acquired Intangible Assets (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 2,430
Accumulated Amortization	76
Carrying Value	$ 2,354
Customer Relationship [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)	12 years
Gross Amount	$ 2,320
Accumulated Amortization	73
Carrying Value	$ 2,247
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)	12 years
Gross Amount	$ 110
Accumulated Amortization	3
Carrying Value	$ 107

Property, Plant and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment, Net

Property, plant and equipment, net consisted of the following (in thousands):


	December 31,
	2023			2022
Transplant aircraft	$	141,855		$	—
Flight school aircraft		3,484			—
OCS Consoles		14,491			10,878
Manufacturing equipment		6,898			3,721
Computer equipment and software		3,021			2,064
Laboratory equipment		1,875			671
Office, trade show and training equipment		4,006			2,121
Leasehold improvements		13,354			12,415
Construction-in-progress		6,250			482
		195,234			32,352
Less: Accumulated depreciation and amortization		(21,293	)		(13,129	)
	$	173,941		$	19,223

Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2022	Dec. 31, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Preferred stock, shares authorized		25,000,000	25,000,000
Preferred stock, no par value
Common stock, shares authorized		150,000,000	150,000,000
Common stock, no par value
Common stock, voting rights		Each share of common stock is entitled to one vote on all matters submitted to a vote of the Company’s stockholders.
Common stock, dividends, declared		$ 0
Common stock, dividends, paid		$ 0
Proceeds from issuance of warrants			$ 438
Exercise Price of $8.75 Per Share [Member]
Class Of Stock [Line Items]
Warrants exercised to purchase shares of common stock	50,000
Preferred stock warrants convertible conversion price	$ 8.75
Proceeds from issuance of warrants	$ 400
Exercise Price of $17.47 Per Share [Member]
Class Of Stock [Line Items]
Preferred stock warrants shares issued upon conversion		14,440
Preferred stock warrants convertible conversion price		$ 17.47
Class of warrant or rights expiration date		May 06, 2024

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2023

Accrued Expenses And Other Current Liabilities [Abstract]

Accrued Expenses and Other Current Liabilities

7. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	December 31,
	2023		2022
Accrued payroll and related expenses	$	20,300	$	9,812
Accrued transportation costs		4,381		2,581
Accrued research, development and clinical trials expenses		1,771		1,876
Accrued other		11,769		4,366
	$	38,221	$	18,635

Inventory (Tables)

12 Months Ended

Dec. 31, 2023

Inventory Disclosure [Abstract]

Schedule of Inventory, Current

Inventory consisted of the following (in thousands):


	December 31,
	2023		2022
Raw materials	$	25,823	$	10,939
Work-in-process		3,806		1,876
Finished goods		14,606		7,790
	$	44,235	$	20,605