TransMedics (TMDX) 10-Q 8 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Oct. 31, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
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
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		32,647,698
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
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, No Par Value
Trading Symbol	TMDX
Security Exchange Name	NASDAQ

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash	$ 427,110	$ 201,182
Accounts receivable	60,654	27,611
Inventory	39,365	20,605
Prepaid expenses and other current assets	9,595	2,896
Total current assets	536,724	252,294
Property, plant and equipment, net	131,004	19,223
Operating lease right-of-use assets	6,861	5,130
Restricted cash	500	500
Goodwill	11,673
Acquired intangible assets, net	2,405
Other non-current assets	60
Total assets	689,227	277,147
Current liabilities:
Accounts payable	12,836	3,341
Accrued expenses and other current liabilities	31,651	18,635
Deferred revenue	2,629	241
Operating lease liabilities	1,985	1,444
Total current liabilities	49,101	23,661
Convertible senior notes, net	446,448
Long-term debt, net	58,986	58,696
Operating lease liabilities, net of current portion	8,232	7,415
Total liabilities	562,767	89,772
Commitments and contingencies (Note 12)
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; 32,642,130 shares and 32,141,368 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively	634,458	666,277
Accumulated other comprehensive loss	(262)	(225)
Accumulated deficit	(507,736)	(478,677)
Total stockholders' equity	126,460	187,375
Total liabilities and stockholders' equity	$ 689,227	$ 277,147

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 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	32,642,130	32,141,368
Common Stock, Shares, Outstanding	32,642,130	32,141,368

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue:
Total revenue	$ 66,430	$ 25,683	$ 160,449	$ 62,084
Cost of revenue:
Total cost of revenue	25,768	7,568	54,280	17,515
Gross profit	40,662	18,115	106,169	44,569
Operating expenses:
Research, development and clinical trials	11,132	6,808	25,294	21,056
Acquired in-process research and development expenses	27,212		27,212
Selling, general and administrative	30,653	16,851	84,993	48,171
Total operating expenses	68,997	23,659	137,499	69,227
Loss from operations	(28,335)	(5,544)	(31,330)	(24,658)
Other income (expense):
Interest expense	(3,590)	(787)	(7,186)	(2,719)
Other income (expense), net	4,996	(1,076)	7,982	(2,087)
Total other income (expense), net	1,406	(1,863)	796	(4,806)
Loss before income taxes	(26,929)	(7,407)	(30,534)	(29,464)
(Provision) benefit for income taxes	1,507	(19)	1,475	(47)
Net loss	$ (25,422)	$ (7,426)	$ (29,059)	$ (29,511)
Net loss per share attributable to common stockholders, basic	$ (0.78)	$ (0.25)	$ (0.89)	$ (1.03)
Net loss per share attributable to common stockholders, diluted	$ (0.78)	$ (0.25)	$ (0.89)	$ (1.03)
Weighted average common shares outstanding, basic	32,614,059	30,229,936	32,474,522	28,729,649
Weighted average common shares outstanding, diluted	32,614,059	30,229,936	32,474,522	28,729,649
Net product revenue [Member]
Revenue:
Total revenue	$ 47,740	$ 21,299	$ 124,195	$ 54,160
Cost of revenue:
Total cost of revenue	11,086	4,231	26,950	11,689
Service Revenue [Member]
Revenue:
Total revenue	18,690	4,384	36,254	7,924
Cost of revenue:
Total cost of revenue	$ 14,682	$ 3,337	$ 27,330	$ 5,826

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (25,422)	$ (7,426)	$ (29,059)	$ (29,511)
Other comprehensive income (loss):
Foreign currency translation adjustment	(42)	(41)	(37)	(95)
Unrealized gains on marketable securities, net of tax of $0		100		36
Total other comprehensive income (loss)	(42)	59	(37)	(59)
Comprehensive loss	$ (25,464)	$ (7,367)	$ (29,096)	$ (29,570)

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ 0	$ 0	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
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	202	$ 202
Issuance of common stock upon the exercise of common stock options, Shares		164,503
Issuance of common stock in connection with employee stock purchase plan	203	$ 203
Issuance of common stock in connection with employee stock purchase plan, Shares		12,465
Stock-based compensation expense	2,310	$ 2,310
Foreign currency translation adjustment	(24)		(24)
Unrealized losses on marketable securities	(73)		(73)
Net loss	(10,562)			(10,562)
Balance at Mar. 31, 2022	59,910	$ 513,203	(285)	(453,008)
Balance, Shares at Mar. 31, 2022		27,968,583
Balance at Dec. 31, 2021	67,854	$ 510,488	(188)	(442,446)
Balance, Shares at Dec. 31, 2021		27,791,615
Foreign currency translation adjustment	(95)
Unrealized losses on marketable securities	36
Net loss	(29,511)
Balance at Sep. 30, 2022	187,857	$ 660,061	(247)	(471,957)
Balance, Shares at Sep. 30, 2022		31,933,984
Balance at Dec. 31, 2021	67,854	$ 510,488	(188)	(442,446)
Balance, Shares at Dec. 31, 2021		27,791,615
Net loss	(36,200)
Balance at Dec. 31, 2022	187,375	$ 666,277	(225)	(478,677)
Balance, Shares at Dec. 31, 2022		32,141,368
Balance at Mar. 31, 2022	59,910	$ 513,203	(285)	(453,008)
Balance, Shares at Mar. 31, 2022		27,968,583
Issuance of common stock upon the exercise of common stock options	237	$ 237
Issuance of common stock upon the exercise of common stock options, Shares		31,592
Stock-based compensation expense	2,316	$ 2,316
Issuance of restricted common stock		23,120
Foreign currency translation adjustment	(30)		(30)
Unrealized losses on marketable securities	9		9
Net loss	(11,523)			(11,523)
Balance at Jun. 30, 2022	50,919	$ 515,756	(306)	(464,531)
Balance, Shares at Jun. 30, 2022		28,023,295
Issuance of common stock in public offering, net of discounts and issuance costs, Shares		3,737,500
Issuance of common stock in public offering, net of discounts and issuance costs	139,854	$ 139,854
Issuance of common stock upon the exercise of common stock options	1,441	$ 1,441
Issuance of common stock upon the exercise of common stock options, Shares		154,316
Issuance of common stock in connection with employee stock purchase plan	306	$ 306
Issuance of common stock in connection with employee stock purchase plan, Shares		17,678
Stock-based compensation expense	2,704	$ 2,704
Restricted common stock forfeitures		(1,778)
Issuance of restricted common stock		2,973
Foreign currency translation adjustment	(41)		(41)
Unrealized losses on marketable securities	100		100
Net loss	(7,426)			(7,426)
Balance at Sep. 30, 2022	187,857	$ 660,061	(247)	(471,957)
Balance, Shares at Sep. 30, 2022		31,933,984
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	3,574	$ 3,574
Issuance of common stock upon the exercise of common stock options, Shares		378,500
Issuance of common stock in connection with employee stock purchase plan	384	$ 384
Issuance of common stock in connection with employee stock purchase plan, Shares		14,135
Stock-based compensation expense	3,921	$ 3,921
Foreign currency translation adjustment	7		7
Net loss	(2,636)			(2,636)
Balance at Mar. 31, 2023	192,625	$ 674,156	(218)	(481,313)
Balance, Shares at Mar. 31, 2023		32,534,003
Balance at Dec. 31, 2022	187,375	$ 666,277	(225)	(478,677)
Balance, Shares at Dec. 31, 2022		32,141,368
Foreign currency translation adjustment	(37)
Net loss	(29,059)
Balance at Sep. 30, 2023	126,460	$ 634,458	(262)	(507,736)
Balance, Shares at Sep. 30, 2023		32,642,130
Balance at Mar. 31, 2023	192,625	$ 674,156	(218)	(481,313)
Balance, Shares at Mar. 31, 2023		32,534,003
Issuance of common stock upon the exercise of common stock options	705	$ 705
Issuance of common stock upon the exercise of common stock options, Shares		39,158
Stock-based compensation expense	4,958	$ 4,958
Purchases of capped calls related to convertible senior notes	(52,072)	$ (52,072)
Issuance of restricted common stock		9,772
Foreign currency translation adjustment	(2)		(2)
Net loss	(1,001)			(1,001)
Balance at Jun. 30, 2023	145,213	$ 627,747	(220)	(482,314)
Balance, Shares at Jun. 30, 2023		32,582,933
Issuance of common stock upon the exercise of common stock options	952	$ 952
Issuance of common stock upon the exercise of common stock options, Shares		47,438
Issuance of common stock in connection with employee stock purchase plan	571	$ 571
Issuance of common stock in connection with employee stock purchase plan, Shares		11,759
Stock-based compensation expense	5,188	$ 5,188
Foreign currency translation adjustment	(42)		(42)
Net loss	(25,422)			(25,422)
Balance at Sep. 30, 2023	$ 126,460	$ 634,458	$ (262)	$ (507,736)
Balance, Shares at Sep. 30, 2023		32,642,130

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	3 Months Ended
	Sep. 30, 2022 USD ($)
Statement of Stockholders' Equity [Abstract]
Discounts and issuance costs	$ 676

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)
Cash flows from operating activities:
Net loss	$ (29,059)	$ (29,511)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	4,572	2,193
Stock-based compensation expense	14,067	7,330
Acquired in-process research and development expenses	27,212
Deferred taxes	(1,540)
Loss on extinguishment of debt		575
Loss on sale of marketable securities		107
Non-cash interest expense and end of term accretion expense	1,358	309
Non-cash lease expense	728	532
Net amortization of premiums on marketable securities		381
Unrealized foreign currency transaction losses	118	1,733
Changes in operating assets and liabilities, net of acquired assets and liabilities:
Accounts receivable	(30,997)	(16,287)
Inventory	(21,029)	(6,094)
Prepaid expenses and other current assets	(2,170)	(98)
Other non-current assets	(54)
Accounts payable	6,541	(3,534)
Accrued expenses and other current liabilities	9,257	(8)
Deferred revenue	765
Operating lease liabilities	(1,101)	590
Net cash used in operating activities	(21,332)	(41,782)
Cash flows from investing activities:
Purchases of property, plant and equipment	(110,029)	(9,143)
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)
Proceeds from sales and maturities of marketable securities		76,916
Net cash provided by (used in) investing activities	(152,135)	57,277
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 and issuance costs paid		58,509
Repayments of long-term debt		(36,050)
Proceeds from issuance of common stock in public offering, net of underwriting discounts and commissions		140,014
Proceeds from issuance of common stock upon exercise of stock options	5,231	1,880
Proceeds from issuance of common stock in connection with employee stock purchase plan	955	509
Net cash provided by financing activities	399,494	164,862
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(99)	(1,475)
Net increase in cash, cash equivalents and restricted cash	225,928	178,882
Cash, cash equivalents and restricted cash, beginning of period	201,682	26,080
Cash, cash equivalents and restricted cash, end of period	427,610	204,962
Supplemental disclosure of non-cash investing and financing activities:
Transfers of inventory to property, plant and equipment	2,224	2,055
Purchases of property, plant and equipment included in accounts payable and accrued expenses	1,724	926
Operating lease liabilities arising from obtaining right-of-use assets	2,171
Offering costs included in accounts payable and accrued expenses		160
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	427,110	204,462
Restricted cash	500	500
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 427,610	$ 204,962

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASHFLOWS (Parenthetical) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Statement of Cash Flows [Abstract]
Convertible senior notes, issuance costs paid	$ 14,620

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (25,422)	$ (1,001)	$ (2,636)	$ (7,426)	$ (11,523)	$ (10,562)	$ (29,059)	$ (29,511)	$ (36,200)

Insider Trading Arrangements

Insider Trading Arrangements	9 Months Ended
	Sep. 30, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	During our fiscal quarter ended September 30, 2023, certain of our directors and officers (as defined in Rule 16a-1(f) under the Exchange Act) entered into contracts, instructions or written plans for the purchase or sale of our securities that are 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 these Rule 10b5-1 trading plans 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 Waleed Hassanein , M.D., Chief Adoption 6-Sep-23 16-Jan-24 31-Dec-24 Common Stock 171,000 Sale Tamer Khayal , Chief Commercial Adoption 6-Sep-23 16-Jan-24 15-Jan-25 Common Stock 139,727 (3) Sale Edward Basile , Director Adoption 6-Sep-23 6-Feb-24 31-Dec-24 Common Stock 27,814 Sale Stephen Gordon , Chief Financial Adoption 14-Sep-23 1-Jan-24 31-Dec-24 Common Stock 77,060 Sale (1) The plans are subject to earlier termination under certain circumstances specified in the plans, 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. (3) Pursuant to the plan, Mr. Khayal may also sell up to 24,776 additional shares of common stock if such shares of common stock remain unsold pursuant to existing 10b5-1 plans entered into by Mr. Khayal and certain of his affiliates upon the termination of such plans and up to 4,359 shares of common stock underlying RSUs that may vest on February 20, 2024, subject to Mr. Khayal’s continued service to the Company as of such date . As of the date of this report, there were 24,776 shares that remained unsold pursuant to such existing plans.
Rule10b5-1 Trading Plan [Member] | Waleed Hassanein [Member]
Trading Arrangements, by Individual
Name	Waleed Hassanein
Title	M.D., Chief Executive Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	6-Sep-23
Termination Date	31-Dec-24	[1]
Aggregate Available	171,000	[2]
Rule10b5-1 Trading Plan [Member] | Tamer Khayal [Member]
Trading Arrangements, by Individual
Name	Tamer Khayal
Title	Chief Commercial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	6-Sep-23
Termination Date	15-Jan-25	[1]
Aggregate Available	139,727	[2],[3]
Rule10b5-1 Trading Plan [Member] | Edward Basile [Member]
Trading Arrangements, by Individual
Name	Edward Basile
Title	Director
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	6-Sep-23
Termination Date	31-Dec-24	[1]
Aggregate Available	27,814	[2]
Rule10b5-1 Trading Plan [Member] | Stephen Gordon [Member]
Trading Arrangements, by Individual
Name	Stephen Gordon
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	14-Sep-23
Termination Date	31-Dec-24	[1]
Aggregate Available	77,060	[2]
[1] The plans are subject to earlier termination under certain circumstances specified in the plans, 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. Subject to adjustments for stock splits, stock combinations, stock dividends and other similar changes to our common stock. Pursuant to the plan, Mr. Khayal may also sell up to 24,776 additional shares of common stock if such shares of common stock remain unsold pursuant to existing 10b5-1 plans entered into by Mr. Khayal and certain of his affiliates upon the termination of such plans and up to 4,359 shares of common stock underlying RSUs that may vest on February 20, 2024, subject to Mr. Khayal’s continued service to the Company as of such date . As of the date of this report, there were 24,776 shares that remained unsold pursuant to such existing plans.

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Nature of the Business and Basis of Presentation	1. 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 organ transportation, to provide transplant programs in the United States with a more efficient process to procure donor organs with the OCS. On August 16, 2023, the Company acquired Summit Aviation, Inc. and Northside Property Group, LLC (together “Summit”). Summit is a charter flight operator based in Bozeman, Montana. The acquisition enabled TransMedics to add aircraft 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 losses since inception, including net losses of $ 29.1 million for the nine months ended September 30, 2023 and $ 36.2 million for the year ended December 31, 2022. As of September 30, 2023, the Company had an accumulated deficit of $ 507.7 million. The Company expects to continue to generate operating losses in the foreseeable future. The Company believes that its existing cash of $ 427.1 million as of September 30, 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 Quarterly Report on Form 10-Q. 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, 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. Continued impacts to the Company’s business as a result of the COVID-19 pandemic may include decreased overall frequency of transplant procedures; disruptions to the Company’s manufacturing operations and supply chain; labor shortages; decreased productivity and unavailability of materials or components; limitations on its employees’ and customers’ ability to travel, and delays in product installations, trainings or shipments to and from other affected countries and within the United States. While the Company maintains an inventory of finished products and raw materials used in its OCS products, a further prolonged pandemic could lead to shortages in the raw materials necessary to manufacture its products. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Unaudited Interim Financial Information The accompanying unaudited interim financial statements and related notes have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K filed with the SEC. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2023 and results of operations for the three and nine months ended September 30, 2023 and 2022 and cash flows for the nine months ended September 30, 2023 and 2022 have been made. The Company’s results of operations for the three and nine months ended September 30, 2023 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2023. 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 unaudited 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 unaudited 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 September 30, 2023 and December 31, 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 three and nine months ended September 30, 2023 , no customer accounted for more than 10 % of revenue. For the three months ended September 30, 2022 , one customer accounted for 13 % of revenue. For the nine months ended September 30, 2022 , one customer accounted for 15 % of revenue. As of September 30, 2023 one customer accounted for 13 % of accounts receivable. As of December 31, 2022 , no customer accounted for more than 10 % 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. 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. 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. 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. 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. 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. 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 common stock equivalents. 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 three and nine months ended September 30, 2023 and 2022. 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 September 30, 2023 2022 Warrants to purchase common stock 64,440 64,440 Options to purchase common stock 3,191,755 3,309,558 Employee stock purchase plan 9,370 8,886 Restricted stock units 241,167 — Restricted stock awards 9,772 24,315 Convertible senior notes 4,893,848 — 8,410,352 3,407,199

Marketable Securities and Fair

Marketable Securities and Fair Value Measurements	9 Months Ended
	Sep. 30, 2023
Marketable Securities and Fair Value Measurements [Abstract]
Marketable Securities and Fair Value Measurements	3. Marketable Securities and Fair Value Measurements The Company did no t have marketable securities as of September 30, 2023 or December 31, 2022. The Company also did no t have assets or liabilities measured at fair value on a recurring basis as of September 30, 2023 or December 31, 2022. Convertible Senior Notes As of September 30, 2023, the carrying value of the Notes was $ 446.4 million (see Note 9) and the estimated fair value of the Notes was $ 426.2 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.

Acquisition of Summit

Acquisition of Summit	9 Months Ended
	Sep. 30, 2023
Business Combinations [Abstract]
Acquisition of Summit	4. Acquisition of Summit On August 16, 2023 , the Company acquired Summit pursuant to the terms of an equity purchase agreement. Summit is a charter flight operator based in Bozeman, Montana. The acquisition enabled TransMedics to add aircraft 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. The final determinations, which are expected to be completed by August 2024, may result in 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 11,673 Total assets acquired 23,442 Accounts payable and other current liabilities ( 6,720 ) Deferred tax liabilities ( 1,540 ) Operating lease liabilities ( 288 ) Total allocation of purchase price consideration, $ 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, and is being amortized to selling, general and administrative over its estimated useful life of 12 years as of the acquisition date on a straight-line basis. 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 no t 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 $ 1.5 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 general and administrative costs in the 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.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Inventory	5. Inventory Inventory consisted of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 18,856 $ 10,939 Work-in-process 3,051 1,876 Finished goods 17,458 7,790 $ 39,365 $ 20,605

Property, Plant and Equipment,

Property, Plant and Equipment, Net	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	6. Property, Plant and Equipment, Net Property, plant and equipment, net consisted of the following (in thousands): September 30, 2023 December 31, 2022 Transplant aircraft $ 102,985 $ — Flight school aircraft 3,484 — OCS Consoles 13,074 10,878 Manufacturing equipment 5,315 3,721 Computer equipment and software 2,782 2,064 Laboratory equipment 765 671 Office, trade show and training equipment 3,030 2,121 Leasehold improvements 12,917 12,415 Construction-in-progress 4,308 482 148,660 32,352 Less: Accumulated depreciation and amortization ( 17,656 ) ( 13,129 ) $ 131,004 $ 19,223 Depreciation and amortization expense of aircraft is recognized using the straight-line method over the estimated useful life of each asset to its salvage value. The estimated useful lives of aircraft are 10 years for transplant aircraft and five years for flight school aircraft. Residual values estimated for transplant and flight school aircraft are approximately 50 % of the original purchase price. Expenditures for repairs and maintenance are charged to expense as incurred. Construction-in-progress as of September 30, 2023 primarily relates to construction of a commercial aircraft hangar at Bozeman Yellowstone International Airport in Bozeman, Montana.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	7. Goodwill and Intangible Assets The carrying amount of goodwill was $ 11.7 million as of September 30, 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): September 30, 2023 Weighted Average Useful Life Gross Amount Accumulated Amortization Carrying Value (in years) Customer relationship 12 $ 2,320 $ 24 $ 2,296 Other 12 110 1 109 $ 2,430 $ 25 $ 2,405 Amortization expense is recorded within selling, general and administrative expense. Future amortization expense of the intangible assets as of September 30, 2023, is expected to be as follows (in thousands): Year Ending December 31, 2023 (three months) $ 49 2024 203 2025 203 2026 203 2027 203 Thereafter 1,544 $ 2,405

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2023
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued Expenses and Other Current Liabilities	8. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued payroll and related expenses $ 15,934 $ 9,812 Accrued transportation costs 4,375 2,581 Accrued research, development and clinical trials expenses 1,261 1,876 Accrued professional fees 2,073 965 Accrued interest 2,683 — Accrued other 5,325 3,401 $ 31,651 $ 18,635

Long-term Debt and Financing Ar

Long-term Debt and Financing Arrangements	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Long-Term Debt and Financing Arrangements	9. Long-Term Debt and Financing Arrangements Convertible Senior Notes Convertible senior notes consisted of the following (in thousands): September 30, 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 ( 13,552 ) Convertible senior notes, net of discount and current portion $ 446,448 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, beginning on December 1, 2023 . 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 sheet and is being accreted to interest expense over the term of the Notes using the effective interest method. During the three and nine months ended September 30, 2023, the Company recognized $ 2.4 million and $ 3.8 million, respectively, in interest expense related to the 1.50 % cash coupon of the Notes and amortization of the debt issuance costs. During the three and nine months ended September 30, 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 in the accompanying consolidated balance sheet. 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 million 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): September 30, 2023 December 31, 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 ( 1,014 ) ( 1,304 ) Long-term debt, net of discount and current portion $ 58,986 $ 58,696 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”) and the Second Amendment to Credit Agreement, dated as of June 23, 2023, by and among the Company, and CIBC (the “Second 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 with OrbiMed Royalty Opportunities II, LP, including $ 35.0 million of principal repayments and a $ 1.1 million end of term payment, as well as accrued interest and the OrbiMed Credit Agreement was terminated. Upon repayment of the outstanding amounts, the Company recorded a loss on extinguishment of debt of $ 0.6 million, which 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 Calls. 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 consideration payable in connection with an individual acquisition and a maximum amount 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 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. 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 sheet 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 September 30, 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 September 30, 2023 , the stated interest rate applicable to borrowings under the CIBC Credit Agreement was 7.3 % . During the three and nine months ended September 30, 2023, the weighted average effective interest rate on outstanding borrowings under the CIBC Credit Agreement was approximately 7.7 % and 7.6 % , respectively.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
Stock-Based Compensation	10. Stock-Based Compensation 2019 Stock Incentive Plan The Company’s 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 canceled 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 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 September 30, 2023, 1,389,390 shares of common stock were available for issuance under the Amended Plan. 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 the Company’s common stock were initially reserved for issuance under the 2019 ESPP. During the nine months ended September 30, 2023 , 25,894 shares of common stock were issued under the 2019 ESPP and as of September 30, 2023 , 264,559 shares of common stock remained available for issuance. 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. As of September 30, 2023, 290,719 shares of common stock remained available for issuance under the Inducement Plan. Stock Option Activity During the nine months ended September 30, 2023, the Company granted options under the 2019 Plan and the Inducement Plan with service-based vesting for the purchase of an aggregate of 473,346 shares of common stock with a weighted average grant-date fair value of $ 45.49 per share. Restricted Stock Unit Activity During the nine months ended September 30, 2023, the Company granted 251,384 restricted stock units under the 2019 Plan and the Inducement Plan with service-based vesting conditions and a weighted-average grant-date fair value of $ 70.21 per share. Stock-Based Compensation The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Cost of revenue $ 112 $ 33 $ 241 $ 89 Research, development and clinical trials expenses 781 394 2,013 1,079 Selling, general and administrative expenses 4,295 2,277 11,813 6,162 $ 5,188 $ 2,704 $ 14,067 $ 7,330 As of September 30, 2023, total unrecognized compensation cost related to unvested share-based awards was $ 46.2 million, which is expected to be recognized over a weighted average period of 2.5 years.

Asset Acquisition

Asset Acquisition	9 Months Ended
	Sep. 30, 2023
Asset Acquisition [Abstract]
Asset Acquisition	11. Asset Acquisition 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 was expensed as research and development expense in the consolidated statements of operations for the three and nine months ended September 30, 2023. Total IPR&D expense related to this acquisition was $ 27.2 million.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Operating Leases The Company leases office, laboratory and manufacturing space under two non-cancelable operating leases. In June 2023, the Company amended one of its lease agreements to add space, resulting in additional lease payments of approximately $ 2.6 million over the remaining term of the leases. There have been no other material changes to the Company’s leases during the nine months ended September 30, 2023. For additional information, please read Note 12 Leases, to the consolidated financial statements in the Company’s Form 10-K for the year ended December 31, 2022. 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 compensation on a pre-tax basis. Company contributions to the plan may be made at the discretion of the board of directors. As of December 31, 2022 , the Company had no t 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 three and nine months ended September 30, 2023, the Company recorded expense of $ 0.3 million and $ 1.0 million, respectively, 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 September 30, 2023 and December 31, 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 September 30, 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.

Segment Reporting and Geographi

Segment Reporting and Geographic Data	9 Months Ended
	Sep. 30, 2023
Segment Reporting [Abstract]
Segment Reporting and Geographic Data	13. Segment Reporting and Geographic Data The Company has determined that it operates in one segment (see Note 2). See Note 14 for revenue by country. Long-lived assets by geography are summarized as follows (in thousands): September 30, 2023 December 31, 2022 Long-lived assets by country(1): United States $ 130,214 $ 18,568 All other countries 790 655 Total long-lived assets $ 131,004 $ 19,223 (1) Long-lived assets consist of property, plant and equipment, net of depreciation, which are categorized based on their location of domicile.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenue	14. Revenue Payments to Customers 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 net impact of such adjustments were insignificant in each of the three and nine months ended September 30, 2023 and 2022. The Company will continue to update its clinical trial accrual estimates as information related to clinical trial payments is received. 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 $ 0.4 million and $ 0.5 million for the three months ended September 30, 2023 and 2022 , respectively, and $ 0.8 million and $ 1.0 million for the nine months ended September 30, 2023 and 2022, 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 $ 0.7 million for the three and nine months ended September 30, 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 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): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 OCS Transplant Revenue by country United States Lung total revenue $ 3,410 $ 1,438 $ 7,658 $ 6,033 Heart total revenue 15,069 9,304 41,481 18,921 Liver total revenue 41,214 12,543 97,002 30,030 Total United States OCS transplant 59,693 23,285 146,141 54,984 All other countries Lung revenue 310 161 964 703 Heart revenue 3,893 2,237 10,803 6,397 Liver revenue 97 — 104 — Total all other countries OCS 4,300 2,398 11,871 7,100 Total OCS transplant revenue $ 63,993 $ 25,683 $ 158,012 $ 62,084 (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 $ 2.4 million for each of the three and nine months ended September 30, 2023 and none for the three and nine months ended September 30, 2022, is not included in this table.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
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 and Chief Executive Officer and a member of the Company’s board of directors. The Company paid Dr. Amira Hassanein approximately $ 0.1 million in total compensation for each of the three months ended September 30, 2023 and 2022, for her services as an employee. The Company paid Dr. Amira Hassanein approximately $ 0.3 million in total compensation for each of the nine months ended September 30, 2023 and 2022 , for her services as an employee.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying unaudited interim financial statements and related notes have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K filed with the SEC. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2023 and results of operations for the three and nine months ended September 30, 2023 and 2022 and cash flows for the nine months ended September 30, 2023 and 2022 have been made. The Company’s results of operations for the three and nine months ended September 30, 2023 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2023.
Use of Estimates	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 unaudited 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 unaudited 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	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 September 30, 2023 and December 31, 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 three and nine months ended September 30, 2023 , no customer accounted for more than 10 % of revenue. For the three months ended September 30, 2022 , one customer accounted for 13 % of revenue. For the nine months ended September 30, 2022 , one customer accounted for 15 % of revenue. As of September 30, 2023 one customer accounted for 13 % of accounts receivable. As of December 31, 2022 , no customer accounted for more than 10 % 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.
Business Combinations	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.
Asset Acquisitions	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.
Goodwill and Acquired Intangible Assets	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.
Fair Value Measurements	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.
Segment Information	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.
Net Income (Loss) per Share	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 common stock equivalents. 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 three and nine months ended September 30, 2023 and 2022. 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 September 30, 2023 2022 Warrants to purchase common stock 64,440 64,440 Options to purchase common stock 3,191,755 3,309,558 Employee stock purchase plan 9,370 8,886 Restricted stock units 241,167 — Restricted stock awards 9,772 24,315 Convertible senior notes 4,893,848 — 8,410,352 3,407,199

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
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 September 30, 2023 2022 Warrants to purchase common stock 64,440 64,440 Options to purchase common stock 3,191,755 3,309,558 Employee stock purchase plan 9,370 8,886 Restricted stock units 241,167 — Restricted stock awards 9,772 24,315 Convertible senior notes 4,893,848 — 8,410,352 3,407,199

Acquisition of Summit (Tables)

Acquisition of Summit (Tables)	9 Months Ended
	Sep. 30, 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 11,673 Total assets acquired 23,442 Accounts payable and other current liabilities ( 6,720 ) Deferred tax liabilities ( 1,540 ) Operating lease liabilities ( 288 ) Total allocation of purchase price consideration, $ 14,894

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventory consisted of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 18,856 $ 10,939 Work-in-process 3,051 1,876 Finished goods 17,458 7,790 $ 39,365 $ 20,605

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment, net consisted of the following (in thousands): September 30, 2023 December 31, 2022 Transplant aircraft $ 102,985 $ — Flight school aircraft 3,484 — OCS Consoles 13,074 10,878 Manufacturing equipment 5,315 3,721 Computer equipment and software 2,782 2,064 Laboratory equipment 765 671 Office, trade show and training equipment 3,030 2,121 Leasehold improvements 12,917 12,415 Construction-in-progress 4,308 482 148,660 32,352 Less: Accumulated depreciation and amortization ( 17,656 ) ( 13,129 ) $ 131,004 $ 19,223

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Acquired Intangible Assets	Acquired intangible assets consisted of the following (in thousands): September 30, 2023 Weighted Average Useful Life Gross Amount Accumulated Amortization Carrying Value (in years) Customer relationship 12 $ 2,320 $ 24 $ 2,296 Other 12 110 1 109 $ 2,430 $ 25 $ 2,405
Future Amortization Expense of Intangible Assets	Future amortization expense of the intangible assets as of September 30, 2023, is expected to be as follows (in thousands): Year Ending December 31, 2023 (three months) $ 49 2024 203 2025 203 2026 203 2027 203 Thereafter 1,544 $ 2,405

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 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): September 30, 2023 December 31, 2022 Accrued payroll and related expenses $ 15,934 $ 9,812 Accrued transportation costs 4,375 2,581 Accrued research, development and clinical trials expenses 1,261 1,876 Accrued professional fees 2,073 965 Accrued interest 2,683 — Accrued other 5,325 3,401 $ 31,651 $ 18,635

Long-term Debt and Financing _2

Long-term Debt and Financing Arrangements (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule of Convertible Senior Notes	Convertible senior notes consisted of the following (in thousands): September 30, 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 ( 13,552 ) Convertible senior notes, net of discount and current portion $ 446,448
Schedule of Long-Term Debt Instruments	Long-term debt consisted of the following (in thousands): September 30, 2023 December 31, 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 ( 1,014 ) ( 1,304 ) Long-term debt, net of discount and current portion $ 58,986 $ 58,696

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
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): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Cost of revenue $ 112 $ 33 $ 241 $ 89 Research, development and clinical trials expenses 781 394 2,013 1,079 Selling, general and administrative expenses 4,295 2,277 11,813 6,162 $ 5,188 $ 2,704 $ 14,067 $ 7,330

Segment Reporting and Geograp_2

Segment Reporting and Geographic Data (Tables)	9 Months Ended
	Sep. 30, 2023
Segment Reporting [Abstract]
Long-lived assets by geographical area	See Note 14 for revenue by country. Long-lived assets by geography are summarized as follows (in thousands): September 30, 2023 December 31, 2022 Long-lived assets by country(1): United States $ 130,214 $ 18,568 All other countries 790 655 Total long-lived assets $ 131,004 $ 19,223 (1) Long-lived assets consist of property, plant and equipment, net of depreciation, which are categorized based on their location of domicile.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
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): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 OCS Transplant Revenue by country United States Lung total revenue $ 3,410 $ 1,438 $ 7,658 $ 6,033 Heart total revenue 15,069 9,304 41,481 18,921 Liver total revenue 41,214 12,543 97,002 30,030 Total United States OCS transplant 59,693 23,285 146,141 54,984 All other countries Lung revenue 310 161 964 703 Heart revenue 3,893 2,237 10,803 6,397 Liver revenue 97 — 104 — Total all other countries OCS 4,300 2,398 11,871 7,100 Total OCS transplant revenue $ 63,993 $ 25,683 $ 158,012 $ 62,084 (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 $ 2.4 million for each of the three and nine months ended September 30, 2023 and none for the three and nine months ended September 30, 2022, is not included in this table.

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accounting Policies [Abstract]
Net loss	$ 25,422	$ 1,001	$ 2,636	$ 7,426	$ 11,523	$ 10,562	$ 29,059	$ 29,511	$ 36,200
Accumulated deficit	507,736						507,736		478,677
Cash	$ 427,110						$ 427,110		$ 201,182

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022	Sep. 30, 2023 USD ($) Segment	Sep. 30, 2022	Dec. 31, 2022 USD ($)
Allowance for credit losses | $	$ 0		$ 0		$ 0
Number of operating segments | Segment			1
Convertible Senior Notes Due 2028 [Member]
Debt instrument, interest rate	1.50%		1.50%
Customer Concentration Risk | Revenue Benchmark | Significant Customer Benchmark [Member] | Minimum [Member]
Concentration risk percentage	10%		10%
Customer Concentration Risk | Revenue Benchmark | Customer One [Member]
Concentration risk percentage		13%		15%
Customer Concentration Risk | Accounts Receivable | Significant Customer Benchmark [Member] | Minimum [Member]
Concentration risk percentage			10%		10%
Customer Concentration Risk | Accounts Receivable | Customer One [Member] | Minimum [Member]
Concentration risk percentage			13%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	8,410,352	3,407,199
Warrants to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	64,440	64,440
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	3,191,755	3,309,558
Employee stock purchase plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	9,370	8,886
Restricted stock units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	241,167
Restricted stock awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	9,772	24,315
Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount	4,893,848

Marketable Securities and Fai_2

Marketable Securities and Fair Value Measurements - Additional Information (Detail) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Marketable Securities and Fair Value Measurements [Abstract]
Marketable Securities	$ 0	$ 0
Assets measured at fair value	0	0
Liabilities measured at fair value	0	$ 0
Carrying value of convertible senior notes	446,448,000
Estimated fair value of convertible senior notes	$ 426,200,000

Acquisition of Summit - Additio

Acquisition of Summit - Additional Information (Detail) - USD ($)		9 Months Ended
	Aug. 16, 2023	Sep. 30, 2023
Business Acquisition [Line Items]
Upfront cash payment		$ 14,894,000
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	1,500,000
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

Acquisition of Summit - Summary

Acquisition of Summit - Summary of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Aug. 16, 2023
Business Acquisition [Line Items]
Goodwill	$ 11,673
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	$ 11,700	11,673
Total assets acquired		23,442
Accounts payable and other current liabilities		(6,720)
Deferred tax liabilities		(1,540)
Operating lease liabilities		(288)
Total allocation of purchase price consideration, net of cash acquired		$ 14,894

Inventory - Schedule of Invento

Inventory - Schedule of Inventory, Current (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials	$ 18,856	$ 10,939
Work-in-process	3,051	1,876
Finished goods	17,458	7,790
Inventory, net	$ 39,365	$ 20,605

Property, Plant and Equipment_3

Property, Plant and Equipment, Net - Schedule of Property, Plant and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 148,660	$ 32,352
Less: Accumulated depreciation and amortization	(17,656)	(13,129)
Property, plant and equipment, net	131,004	19,223
Transplant Aicraft [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	102,985
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	13,074	10,878
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,315	3,721
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,782	2,064
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	765	671
Office, Trade Show and Training Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,030	2,121
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	12,917	12,415
Construction-In-Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4,308	$ 482

Property, Plant and Equipment_4

Property, Plant and Equipment, Net - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2023
Transplant Aicraft [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of aircarft	10 years
Flight School Aircraft [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of aircarft	5 years
Transplant Aircraft and Flight School Aircraft [Member]
Property, Plant and Equipment [Line Items]
Residual value percentage	50%

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2023	Aug. 16, 2023
Goodwill [Line Items]
Carrying amount of goodwill	$ 11,673,000
Impairments to goodwill	0
Summit [Member]
Goodwill [Line Items]
Carrying amount of goodwill	$ 11,700,000	$ 11,673,000

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Acquired Intangible Assets (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 2,430
Accumulated Amortization	25
Carrying Value	$ 2,405
Customer Relationship [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)	12 years
Gross Amount	$ 2,320
Accumulated Amortization	24
Carrying Value	$ 2,296
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)	12 years
Gross Amount	$ 110
Accumulated Amortization	1
Carrying Value	$ 109

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Future Amortization Expense of Intangible Assets (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2023 (three months)	$ 49
2024	203
2025	203
2026	203
2027	203
Thereafter	1,544
Carrying Value	$ 2,405

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued payroll and related expenses	$ 15,934	$ 9,812
Accrued transportation costs	4,375	2,581
Accrued research, development and clinical trials expenses	1,261	1,876
Accrued professional fees	2,073	965
Accrued interest	2,683
Accrued other	5,325	3,401
Accrued expenses and other liabilities current	$ 31,651	$ 18,635

Long-term Debt and Financing _3

Long-term Debt and Financing Arrangements - Schedule of Convertible Senior Notes (Detail) $ in Thousands	Sep. 30, 2023 USD ($)
Debt Instrument [Line Items]
Convertible senior notes, net of discount and current portion	$ 446,448
Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount	460,000
Net of current portion	460,000
Debt discount, net of accretion	$ (13,552)

Long-term Debt and Financing _4

Long-term Debt and Financing Arrangements - Convertible Senior Notes - Additional Information (Detail)			3 Months Ended	9 Months Ended
	May 11, 2023 USD ($) TradingDays $ / shares shares	May 08, 2023	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)
Debt Instrument [Line Items]
Proceeds from Convertible Debt				$ 445,380,000
Debt instrument, frequency of periodic payment	semiannually
Debt instrument, date of first required payment	Dec. 01, 2023
Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Conversion price per share | $ / shares	$ 94
Premium percentage over closing price		32.50%
Maturity date of notes	Jun. 01, 2028
Interest expense, debt			$ 2,400,000	$ 3,800,000
Percentage of cash coupon of notes and amortization of the debt issuance costs			1.50%	1.50%
Proceeds from Convertible Debt	$ 393,300,000
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, beginning on December 1, 2023.
Conversion of per principal amount of notes	$ 1,000
Average effective interest rate			2.10%	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%
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%
Convertible Senior Notes [Member] | Maximum [Member] | Before March 1, 2028 [Member]
Debt Instrument [Line Items]
Conversion price	98%
Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount			$ 460,000,000	$ 460,000,000
Private Placement [Member] | Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount	$ 460,000,000

Long-term Debt and Financing _5

Long-term Debt and Financing Arrangements - Capped Call Transactions - Additional Information (Detail) $ / shares in Units, $ in Thousands		9 Months Ended
	May 11, 2023 USD ($)	Sep. 30, 2023 USD ($) 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

Long-term Debt and Financing _6

Long-term Debt and Financing Arrangements - Schedule of Long-term Debt Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Net of discount and current portion	$ 58,986	$ 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	(1,014)	(1,304)
Net of discount and current portion	$ 58,986	$ 58,696

Long-term Debt and Financing _7

Long-term Debt and Financing Arrangements - Long-term Debt - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Jul. 31, 2022	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Jun. 23, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Repayments of long-term debt				$ 36,050
Loss on extinguishment of debt				$ 575
Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 60,000	$ 60,000			$ 60,000
Orbi Med [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	$ 35,000
Debt instrument, end of term payment accrued interest	1,100
Loss on extinguishment of debt	600
Canadian Imperial Bank of Commerce [Member]
Debt Instrument [Line Items]
Interest rate effective percentage		7.30%	7.30%
Average effective interest rate		7.70%	7.60%
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	$ 10,000
Minimum percentage to maintain total net revenue set forth in total revenue plan presented			75%
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%
Canadian Imperial Bank of Commerce [Member] | Credit Agreement [Member] | Upfront Fees and Other Costs [Member] | Term Loan [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%
Canadian Imperial Bank of Commerce [Member] | Credit Agreement [Member] | Before March 1, 2028 [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee percentage	2%
Canadian Imperial Bank of Commerce [Member] | Credit Agreement [Member] | Calendar Quarter Ending on September 30, 2023 but Before March 1, 2028 [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee percentage	1%
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] | Maximum [Member] | Credit Agreement [Member] | Aggregate All Acquisitions [Member]
Debt Instrument [Line Items]
Credit Agreement Acquisition Cash Consideration					$ 150,000
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%
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%
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%

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended				9 Months Ended
	May 25, 2023	Apr. 15, 2019	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Aug. 31, 2021
Unrecognized compensation cost related to unvested employee and director stock-based awards			$ 46.2				$ 46.2
Weighted average period for unrecognized compensation cost							2 years 6 months
Common Stock
Number of shares issued			11,759	14,135	17,678	12,465
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			1,389,390				1,389,390
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				264,559
Purchase price of common stock, percent		85%
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 share based payment award number of shares available for grant			290,719				290,719
2019 Plan and 2021 Inducement Plan [Member] | Common Stock
Options granted							473,346
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value							$ 45.49
2019 Plan and 2021 Inducement Plan [Member] | Restricted stock units [Member]
Shares granted							251,384
Share-based compensation arrangement by share-based payment award, grants in period, weighted average grant date fair value							$ 70.21

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allocated Share-based Compensation Expense	$ 5,188	$ 2,704	$ 14,067	$ 7,330
Cost of revenue [Member]
Allocated Share-based Compensation Expense	112	33	241	89
Research, development and clinical trials expenses [Member]
Allocated Share-based Compensation Expense	781	394	2,013	1,079
Selling, general and administrative expenses [Member]
Allocated Share-based Compensation Expense	$ 4,295	$ 2,277	$ 11,813	$ 6,162

Asset Acquisition - Additional

Asset Acquisition - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Aug. 02, 2023	Sep. 30, 2023	Sep. 30, 2023
Asset Acquisition [Line Items]
Acquired in-process research and development expenses		$ 27,212	$ 27,212
BTL [Member]
Asset Acquisition [Line Items]
Acquisition, date	Aug. 02, 2023
Acquired in-process research and development expenses			$ 27,200

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Jan. 01, 2023	Jan. 31, 2021	Sep. 30, 2023	Sep. 30, 2023	Dec. 31, 2022	Jun. 30, 2023
Operating lease, additional amount due over remaining lease term						$ 2.6
Defined contribution plan, contribution amount			$ 0.3	$ 1	$ 0
Recorded unconditional purchase commitment, minimum quantity required		$ 9.5
Recorded unconditional purchase commitment, maturity year and month		2029-12
Remaining purchase commitment			$ 7	$ 7
First 3% of Compensation Contributed [Member]
Defined contribution plan, matching percentage of each employee's contribution	100%
100% Match [Member]
Defined contribution plan, percentage of matching contribution	3%
Fifty Percent Match [Member] | Additional Maximum [Member]
Defined contribution plan, percentage of matching contribution	2%
Excess of 3% to 5% of Compensation Contributed [Member]
Defined contribution plan, matching percentage of each employee's contribution	50%

Segment Reporting and Geograp_3

Segment Reporting and Geographic Data - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2023 Segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment Reporting and Geograp_4

Segment Reporting and Geographic Data - Geographic Areas Long-lived Assets (Detail) - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	[1]	$ 131,004	$ 19,223
United States [Member]
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	[1]	130,214	18,568
All Other Countries [Member]
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	[1]	$ 790	$ 655
[1] Long-lived assets consist of property, plant and equipment, net of depreciation, which are categorized based on their location of domicile.

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Research development and clinical trials expenses	$ 0.4	$ 0.5	$ 0.8	$ 1
Payment to customers related to use of aircraft	$ 0.7		$ 0.7

Revenue - Schedule of Net Reven

Revenue - Schedule of Net Revenue by Organ and Country (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue		$ 66,430	$ 25,683	$ 160,449	$ 62,084
OCS transplant revenue
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	63,993	25,683	158,012	62,084
OCS transplant revenue | United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	59,693	23,285	146,141	54,984
OCS transplant revenue | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	4,300	2,398	11,871	7,100
Lung revenue [Member] | OCS transplant revenue | United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	3,410	1,438	7,658	6,033
Lung revenue [Member] | OCS transplant revenue | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	310	161	964	703
Heart revenue [Member] | OCS transplant revenue | United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	15,069	9,304	41,481	18,921
Heart revenue [Member] | OCS transplant revenue | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	3,893	2,237	10,803	6,397
Liver revenue [Member] | OCS transplant revenue | United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	41,214	$ 12,543	97,002	$ 30,030
Liver revenue [Member] | OCS transplant revenue | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	$ 97		$ 104
[1] Revenue by country is categorized based on the location of the end customer. Total revenue includes product and service revenue. Service revenue unrelated to OCS transplant, which was $ 2.4 million for each of the three and nine months ended September 30, 2023 and none for the three and nine months ended September 30, 2022, is not included in this table.

Revenue - Revenue - Schedule of

Revenue - Revenue - Schedule of Net Revenue by Organ and Country (Parenthetical) (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 66,430,000	$ 25,683,000	$ 160,449,000	$ 62,084,000
Unrelated to OCS Transplant [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 2,400,000	$ 0	$ 2,400,000	$ 0

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Director [Member]
Related Party Transaction [Line Items]
Compensation expense	$ 0.1	$ 0.1	$ 0.3	$ 0.3