TransMedics (TMDX) 10-Q2 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2024	Apr. 30, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
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		32,937,296
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	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash	$ 350,217	$ 394,812
Accounts receivable	81,942	63,576
Inventory	48,541	44,235
Prepaid expenses and other current assets	7,606	8,031
Total current assets	488,306	510,654
Property, plant and equipment, net	214,421	173,941
Operating lease right-of-use assets	6,226	6,546
Restricted cash	500	500
Goodwill	11,990	11,990
Acquired intangible assets, net	2,303	2,354
Other non-current assets	85	62
Total assets	723,831	706,047
Current liabilities:
Accounts payable	9,225	12,717
Accrued expenses and other current liabilities	36,852	38,221
Deferred revenue	2,060	1,961
Operating lease liabilities	2,086	2,035
Total current liabilities	50,223	54,934
Convertible senior notes, net	447,835	447,140
Long-term debt, net	59,141	59,064
Operating lease liabilities, net of current portion	7,161	7,707
Total liabilities	564,360	568,845
Commitments and contingencies (Note 11)
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; 32,851,376 shares and 32,670,803 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	651,161	641,106
Accumulated other comprehensive loss	(182)	(199)
Accumulated deficit	(491,508)	(503,705)
Total stockholders' equity	159,471	137,202
Total liabilities and stockholders' equity	$ 723,831	$ 706,047

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
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	32,851,376	32,670,803
Common Stock, Shares, Outstanding	32,851,376	32,670,803

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue:
Total revenue	$ 96,850	$ 41,554
Cost of revenue:
Total cost of revenue	36,888	12,788
Gross profit	59,962	28,766
Operating expenses:
Research, development and clinical trials	11,380	5,871
Selling, general and administrative	36,161	24,984
Total operating expenses	47,541	30,855
Income (loss) from operations	12,421	(2,089)
Other income (expense):
Interest expense	(3,598)	(1,091)
Interest income and other income (expense)	3,570	555
Total other expense, net	(28)	(536)
Income (loss) before income taxes	12,393	(2,625)
Provision for income taxes	(196)	(11)
Net income (loss)	$ 12,197	$ (2,636)
Net income (loss) per share, basic	$ 0.37	$ (0.08)
Net income (loss) per share, diluted	$ 0.35	$ (0.08)
Weighted average common shares outstanding, basic	32,760,190	32,260,267
Weighted average common shares outstanding, diluted	34,678,895	32,260,267
Net product revenue [Member]
Revenue:
Total revenue	$ 61,325	$ 33,993
Cost of revenue:
Total cost of revenue	14,084	7,306
Service Revenue [Member]
Revenue:
Total revenue	35,525	7,561
Cost of revenue:
Total cost of revenue	$ 22,804	$ 5,482

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 12,197	$ (2,636)
Other comprehensive income:
Foreign currency translation adjustment	17	7
Total other comprehensive income	17	7
Comprehensive income (loss)	$ 12,214	$ (2,629)

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, 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 income (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, 2023	137,202	$ 641,106	(199)	(503,705)
Balance, Shares at Dec. 31, 2023		32,670,803
Issuance of common stock upon the exercise of common stock options	2,547	$ 2,547
Issuance of common stock upon the exercise of common stock options, Shares		113,023
Issuance of common stock in connection with employee stock purchase plan	638	$ 638
Issuance of common stock in connection with employee stock purchase plan, Shares		9,506
Vesting of restricted stock units, Shares		58,044
Stock-based compensation expense	6,870	$ 6,870
Foreign currency translation adjustment	17		17
Net income (loss)	12,197			12,197
Balance at Mar. 31, 2024	$ 159,471	$ 651,161	$ (182)	$ (491,508)
Balance, Shares at Mar. 31, 2024		32,851,376

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net income (loss)	$ 12,197	$ (2,636)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization expense	4,302	1,287
Stock-based compensation expense	6,870	3,921
Non-cash interest expense and end of term accretion expense	772	106
Non-cash lease expense	321	191
Unrealized foreign currency transaction (gains) losses	199	(137)
Changes in operating assets and liabilities:
Accounts receivable	(18,407)	(10,962)
Inventory	(5,613)	(3,623)
Prepaid expenses and other current assets	(1,576)	(884)
Other non-current assets	(24)	(54)
Accounts payable	(2,039)	1,028
Accrued expenses and other current liabilities	(49)	3,454
Deferred revenue	108
Operating lease liabilities	(496)	(352)
Net cash used in operating activities	(3,435)	(8,661)
Cash flows from investing activities:
Purchases of property, plant and equipment	(44,172)	(927)
Net cash used in investing activities	(44,172)	(927)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	2,547	3,574
Proceeds from issuance of common stock in connection with employee stock purchase plan	638	384
Net cash provided by financing activities	3,185	3,958
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(173)	73
Net decrease in cash, cash equivalents and restricted cash	(44,595)	(5,557)
Cash, cash equivalents and restricted cash, beginning of period	395,312	201,682
Cash, cash equivalents and restricted cash, end of period	350,717	196,125
Supplemental disclosure of non-cash activities:
Transfers of inventory to property, plant and equipment	1,215	317
Purchases of property, plant and equipment included in accounts payable and accrued expenses	1,180	30
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	350,217	195,375
Restricted cash	500	750
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 350,717	$ 196,125

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 12,197	$ (2,636)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	3 Months Ended
Nature of the Business and Basis of Presentation	Mar. 31, 2024
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 logistics services, to provide transplant programs in the United States with a more efficient process to procure donor organs with the OCS. The Company's logistics services include aviation transportation, ground transportation and other coordination activity. On August 16, 2023, the Company acquired Summit Aviation, Inc. and Northside Property Group, LLC (together “Summit”). Summit was a charter flight operator based in Bozeman, Montana. The acquisition enabled TransMedics to add aviation transportation services to its NOP and become a comprehensive national provider of donor organ retrieval and delivery in the United States. The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company believes that its existing cash of $ 350.2 million as of March 31, 2024 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. However, the Company in the future may need to seek additional funding through equity financings, debt financings or strategic alliances. The Company may not be able to obtain financing on acceptable terms, or at all, and the terms of any financing may adversely affect the holdings or the rights of the Company’s shareholders. If the Company is unable to obtain funding when needed, the Company will be required to delay, reduce or eliminate some or all of its research and development programs, product expansion or commercialization efforts, or the Company may be unable to continue operations. The Company is subject to risks and uncertainties common to companies in the medical device industry and of similar size, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, uncertainty of market acceptance of products, and the need to obtain additional financing to fund operations. Products currently under development will require additional research and development efforts, including additional clinical testing and regulatory approval, prior to commercialization. These efforts require additional capital, adequate personnel, infrastructure and extensive compliance-reporting capabilities. The Company’s research and development may not be successfully completed, adequate protection for the Company’s technology may not be obtained, the Company may not obtain necessary government regulatory approval on its expected timeline or at all, and approved products may not prove commercially viable. The Company operates in an environment of rapid change in technology and competition. The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2024
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, 2023 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 March 31, 2024 and results of operations for the three months ended March 31, 2024 and 2023 and cash flows for the three months ended March 31, 2024 and 2023 have been made. The Company’s results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 . 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 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 March 31, 2024 and December 31, 2023, the Company had no allowance for credit losses. 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. 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 accompanying consolidated balance sheets, and the fair value of the Notes is presented at each reporting period for disclosure purposes only (see Note 8) . Spare Parts Inventory Spare parts are used in aviation operations and are generally not for sale. Spare parts inventory is comprised of repairable and expendable spare aircraft parts, which are valued at the lower of cost or net realizable value, using the specific identification method. Storage costs and miscellaneous materials and supplies costs related to inventory or to support flight equipment are expensed as incurred. As of March 31, 2024, spare parts inventory of $ 0.6 million is included within prepaid expenses and other current assets on the accompanying consolidated balance sheets. The Company had no spare parts inventory as of December 31, 2023. The Company determines, based on the evidence that exists, whether or not it is appropriate to maintain a reserve for excess and obsolete spare parts inventory. The reserve is based on historical experience related to the disposal of inventory due to damage, physical deterioration, obsolescence, or other causes. As of March 31, 2024 and December 31, 2023, the Company had no allowance for spare parts excess and obsolescence . 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. Foreign Currency Translation The functional currency of each of the Company’s foreign subsidiaries is the currency of the local country. Assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars using the period-end exchange rates, and income and expense items are translated into U.S. dollars using average exchange rates in effect during each period. The effects of these foreign currency translation adjustments are included in accumulated other comprehensive income (loss), a separate component of stockholders’ equity. The Company also incurs transaction gains and losses resulting from intercompany transactions as well as transactions with customers or vendors denominated in currencies other than the functional currency of the legal entity in which the transaction is recorded. Realized and unrealized foreign currency transaction gains (losses) are included in the consolidated statements of operations as a component of other income (expense) and totaled $( 0.2 ) million and $ 0.1 million, for the three months ended March 31, 2024 and 2023 , respectively. Recently issued accounting pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently assessing the impact of the adoption of this guidance. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public entities, on an annual basis, to provide disclosure of specific categories in their tax rate reconciliations, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently assessing the impact of the adoption of this guidance.

Acquisition of Summit

Acquisition of Summit	3 Months Ended
Acquisition of Summit	Mar. 31, 2024
Business Combinations [Abstract]
Acquisition of Summit	3. Acquisition of Summit On August 16, 2023 , the Company acquired Summit pursuant to the terms of an equity purchase agreement. Summit was a charter flight operator based in Bozeman, Montana. The acquisition enabled TransMedics to add aviation transportation services to its NOP and become a comprehensive national provider of donor organ retrieval and delivery in the United States. The acquisition was accounted for as a purchase of a business under ASC Topic 805, Business Combinations. Under the acquisition method of accounting, the assets and liabilities were recorded as of the acquisition date, at their respective fair values. The preliminary purchase consideration of $ 14.9 million reflected an upfront cash payment of $ 18.0 million, net of cash acquired and working capital adjustments. The Company’s consolidated financial statements reflect the preliminary allocation of the purchase price to the assets and liabilities assumed based on fair value as of the date of the acquisition. The Company's estimate of preliminary purchase consideration is subject to change upon finalizing working capital adjustments. The Company’s preliminary estimate of the fair value of specifically identifiable assets acquired and liabilities assumed as of the date of acquisition is subject to change upon finalizing its valuation analysis. During the three months ended December 31, 2023, the Company recorded an adjustment to goodwill of $ 0.3 million, representing an adjustment to its estimate of the fair value of accounts payable and deferred tax liabilities as of the acquisition date. The final determinations, which are expected to be completed by August 2024, may result in additional changes in the fair value of certain assets and liabilities as compared to these preliminary estimates. The following table summarizes the preliminary allocation of the purchase price (in thousands): Assets Acquired and Liabilities Assumed: Accounts receivable $ 2,089 Other current assets 1,040 Property, plant and equipment 5,922 Right-of-use asset 288 Intangible assets 2,430 Goodwill 11,990 Total assets acquired 23,759 Accounts payable and other current liabilities ( 6,917 ) Deferred tax liabilities ( 1,660 ) Operating lease liabilities ( 288 ) Total allocation of purchase price consideration, $ 14,894 Property, plant and equipment consist primarily of flight school aircraft and construction-in-progress related to a commercial aircraft hangar that Summit is in the process of constructing. Flight school aircraft were valued using market comparisons adjusted for aircraft-specific condition. The fair value of construction-in-progress approximated its cost. Intangible assets consisted primarily of a customer relationship asset of $ 2.3 million related to flight school revenue and was valued using the multi-period excess earnings method, a form of the income approach. Significant assumptions and estimates utilized in this model include the revenue growth rate, contract renewal probability and the discount rate. Intangible assets are being amortized on a straight-line basis to selling, general and administrative over their estimated useful lives of 12 years as of the acquisition date. Goodwill was recognized for the excess purchase price over the fair value of the net assets acquired. Goodwill is primarily attributable to the workforce of the acquired business (which is not eligible for separate recognition as an identifiable intangible asset) and anticipated synergies between Summit’s existing business processes and the NOP. Goodwill from the acquisition is included within the Company’s one reporting unit and is included in the Company’s enterprise-level annual review for impairment. Goodwill resulting from the acquisition is 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 existing deferred tax assets. Therefore, the Company recorded a tax benefit of $ 1.7 million during the three months ended September 30, 2023 for the release of a portion of its valuation allowance related to the net deferred tax liabilities recorded in purchase accounting.

Inventory

Inventory	3 Months Ended
Inventory	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventory	4. Inventory Inventory consisted of the following (in thousands): March 31, 2024 December 31, 2023 Raw materials $ 25,520 $ 25,823 Work-in-process 4,525 3,806 Finished goods 18,496 14,606 $ 48,541 $ 44,235

Property, Plant and Equipment,

Property, Plant and Equipment, Net	3 Months Ended
Property, Plant and Equipment, Net	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	5. Property, Plant and Equipment, Net Property, plant and equipment, net consisted of the following (in thousands): March 31, 2024 December 31, 2023 Transplant aircraft $ 181,236 $ 141,855 Flight school aircraft 3,484 3,484 OCS Consoles 15,369 14,491 Manufacturing equipment 7,669 6,898 Computer equipment and software 3,283 3,021 Laboratory equipment 2,344 1,875 Office, trade show and training equipment 4,200 4,006 Leasehold improvements 13,938 13,354 Construction-in-progress 8,397 6,250 239,920 195,234 Less: Accumulated depreciation and amortization ( 25,499 ) ( 21,293 ) $ 214,421 $ 173,941 During the three months ended March 31, 2024 and 2023, total depreciation and amortization expense was $ 4.3 million and $ 1.3 million, respectively. Construction-in-progress as of March 31, 2024 and December 31, 2023 primarily relates to construction of a commercial aircraft hangar at Bozeman Yellowstone International Airport in Bozeman, Montana. Substantially all of the Company's property, plant and equipment are held in the United States.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
Goodwill and Intangible Assets	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6. Goodwill and Intangible Assets The carrying amount of goodwill was $ 12.0 million as of March 31, 2024 and December 31, 2023 and 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): March 31, 2024 Weighted Average Useful Life Gross Amount Accumulated Amortization Carrying Value (in years) Customer relationship 12 $ 2,320 $ 121 $ 2,199 Other 12 110 6 104 $ 2,430 $ 127 $ 2,303 December 31, 2023 Weighted Average Useful Life Gross Amount Accumulated Amortization Carrying Value (in years) Customer relationship 12 $ 2,320 $ 73 $ 2,247 Other 12 110 3 107 $ 2,430 $ 76 $ 2,354 Amortization expense is recorded within selling, general and administrative expense. Amortization expense was $ 0.1 million for the three months ended March 31, 2024 . Future amortization expense of the intangible assets as of March 31, 2024 is expected to be as follows (in thousands): Year Ending December 31, 2024 (nine months) $ 152 2025 203 2026 203 2027 203 2028 203 Thereafter 1,339 $ 2,303

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
Accrued Expenses and Other Current Liabilities	Mar. 31, 2024
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued Expenses and Other Current Liabilities	7. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2024 December 31, 2023 Accrued payroll and related expenses $ 16,413 $ 20,300 Accrued transportation costs 4,902 4,381 Accrued research, development and clinical trials expenses 2,479 1,771 Accrued other 13,058 11,769 $ 36,852 $ 38,221

Long-term Debt and Financing Ar

Long-term Debt and Financing Arrangements	3 Months Ended
Long-term Debt and Financing Arrangements	Mar. 31, 2024
Debt Disclosure [Abstract]
Long-Term Debt and Financing Arrangements	8. Long-Term Debt and Financing Arrangements Convertible Senior Notes The Notes consisted of the following (in thousands): March 31, 2024 December 31, 2023 Principal amount of convertible senior notes $ 460,000 $ 460,000 Less: Current portion of convertible senior notes — — Convertible senior notes, net of current portion 460,000 460,000 Debt discount, net of accretion ( 12,165 ) ( 12,860 ) Convertible senior notes, net of discount and current portion $ 447,835 $ 447,140 On May 11, 2023, the Company issued $ 460.0 million aggregate principal amount of the Notes, in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act, pursuant to an indenture dated May 11, 2023, by and between the Company and U.S. Bank Trust Company, National Association (the “Indenture”). The initial conversion price of the Notes is approximately $ 94.00 per share of common stock, which represents a premium of approximately 32.5 % over the closing price of the Company’s common stock on May 8, 2023. The Notes will mature on June 1, 2028 , unless earlier repurchased, redeemed or converted. The Company used $ 52.1 million of the proceeds from the sale of the Notes to fund the cost of entering into capped call transactions, described below. The proceeds from the issuance of the Notes were approximately $ 393.3 million, net of capped call transaction costs of $ 52.1 million and initial purchaser discounts and other debt issuance costs totaling $ 14.6 million. The Notes bear interest at a rate of 1.50 % per year and interest is payable semiannually in arrears on June 1 and December 1 of each year. The initial conversion rate is 10.6388 shares of common stock per $ 1,000 principal amount of the Notes, which represents an initial conversion price of approximately $ 94.00 per share of common stock. The conversion rate and conversion price are subject to customary adjustments upon the occurrence of certain events as described in the Indenture. Before March 1, 2028 , noteholders have the right to convert their Notes only upon the occurrence of certain events, including certain corporate events, and during the five business days immediately after any ten consecutive trading days in which the trading price per $ 1,000 principal amount of Notes is less than ninety eight percent ( 98 %) of the as converted value. Additionally, the noteholder can convert their Notes during any calendar quarter (and only during such calendar quarter), commencing after the calendar quarter ending on September 30, 2023 but before March 1, 2028 , provided the last reported sale price of the common stock for at least 20 trading days is greater than or equal to 130 % of the conversion price during the 30 consecutive trading days ending on the last trading day of a calendar quarter. From and after March 1, 2028, noteholders may convert their Notes at any time at their election until the close of business on the second scheduled trading day immediately before the maturity date. The Company has the right to elect to settle conversions either in cash, shares or in a combination of cash and shares of its common stock. Prior to June 8, 2026, the Notes will not be redeemable. On or after June 8, 2026, the Company may redeem for cash all or any portion of the Notes (subject to the partial redemption limitation set forth in the Indenture), at its option, if the last reported sale price of the Company’s common stock has been at least 130 % of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption. In addition, calling any Note for redemption will constitute a “Make-Whole Fundamental Change” (as defined in the Indenture) with respect to that Note, in which case the conversion rate applicable to the conversion of that Note will be increased in certain circumstances if it is converted after it is called for redemption. During the three months ended March 31, 2024, the Company recognized $ 2.4 million in interest expense related to the 1.50 % cash coupon of the Notes and amortization of the debt issuance costs. During the three months ended March 31, 2024, the effective interest rate on the outstanding Notes was approximately 2.1 % . As of March 31, 2024, the estimated fair value of the Notes was $ 506.4 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. 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 was recorded as a reduction to common stock in the accompanying consolidated balance sheets. Each of the Capped Calls has an initial strike price of approximately $ 94.00 per share, subject to certain adjustments, which corresponds to the initial conversion price of the Notes. The Capped Calls have an initial cap price of $ 141.88 per share, subject to certain adjustments. The Capped Calls cover, subject to anti-dilution adjustments, approximately 4,893,848 shares of the Company’s common stock, which is the same number of shares of the Company’s common stock initially underlying the Notes. The Capped Calls are subject to automatic exercise over a 40 trading day period commencing on April 3, 2028 , subject to earlier termination under certain circumstances. Long-term debt Long-term debt consisted of the following (in thousands): March 31, 2024 December 31, 2023 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 ( 859 ) ( 936 ) Long-term debt, net of discount and current portion $ 59,141 $ 59,064 In July 2022, the Company entered into a credit agreement with Canadian Imperial Bank of Commerce (“CIBC”), as amended by the First Amendment to Credit Agreement, dated as of May 8, 2023, by and among the Company and CIBC (the “First Amendment”), the Second Amendment to Credit Agreement, dated as of June 23, 2023, by and among the Company and CIBC (the “Second Amendment”) and the Third Amendment to Credit Agreement, dated as of November 9, 2023, by and among the Company and CIBC (the “Third Amendment”) (as amended, the “CIBC Credit Agreement”), pursuant to which the Company borrowed $ 60.0 million. 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 1.0 % if paid on or after 12 months after the closing date but prior to 24 months after the closing date. 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), as defined, 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. 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 March 31, 2024 , the Company was in compliance with all 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. During the three months ended March 31, 2024 and 2023, the Company recognized $ 1.2 million and $ 1.1 million, respectively, in interest expense related to the CIBC borrowings. During the three months ended March 31, 2024 and 2023, the weighted average effective interest rate on outstanding borrowings under the CIBC Credit Agreement was approximately 7.8 % and 7.3 %, respectively. As of March 31, 2024, the stated interest rate applicable to borrowings under the CIBC Credit Agreement was 7.3 % .

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
Stock-Based Compensation	Mar. 31, 2024
Stockholders' Equity Note [Abstract]
Stock-Based Compensation	9. 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 cancelled without the delivery of shares, are forfeited to or repurchased by TransMedics Group or otherwise become available again for grant. Since the effectiveness of the Company’s 2019 Plan in April 2019, no awards have been 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 March 31, 2024, 929,897 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 three months ended March 31, 2024 , 9,506 shares of common stock were issued under the 2019 ESPP and as of March 31, 2024 , 255,053 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. On November 2, 2023, the Company's Board of Directors approved an increase of 500,000 to shares available under the Inducement Plan. As of March 31, 2024, 564,538 shares of common stock remained available for issuance under the Inducement Plan. Stock Option Activity During the three months ended March 31, 2024, the Company granted options under the 2019 Plan and the Inducement Plan with service-based vesting for the purchase of an aggregate of 304,976 shares of common stock with a weighted average grant-date fair value of $ 53.48 per share. Restricted Stock Unit Activity During the three months ended March 31, 2024, the Company granted 198,860 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 $ 82.77 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 March 31, 2024 2023 Cost of revenue $ 364 $ 49 Research, development and clinical trials expenses 878 518 Selling, general and administrative expenses 5,628 3,354 $ 6,870 $ 3,921 As of March 31, 2024, total unrecognized compensation cost related to unvested share-based awards was $ 73.4 million, which is expected to be recognized over a weighted average period of 2.6 years.

Net Income (Loss) per Share

Net Income (Loss) per Share	3 Months Ended
Net Income (Loss) per Share	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Income (Loss) per Share	10. Net Income (Loss) per Share Basic net income (loss) per common share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock awards, using the treasury stock method, and outstanding convertible notes, using the if-converted method. A reconciliation of the numerators and the denominators of the basic and dilutive net income (loss) per common share computations are as follows (in thousands, except share and per share amounts): Three Months Ended March 31, 2024 2023 Numerator: Net income (loss) $ 12,197 $ ( 2,636 ) Denominator: Weighted average basic common shares outstanding 32,760,190 32,260,267 Effect of dilutive securities: Options to purchase common stock 1,773,345 — Restricted stock units 126,797 — Warrants to purchase common stock 11,379 — Restricted stock awards 7,184 — Weighted average dilutive common shares outstanding 34,678,895 32,260,267 Net income (loss) per share: Basic $ 0.37 $ ( 0.08 ) Diluted $ 0.35 $ ( 0.08 ) The Company excluded the following potential common shares, presented based on weighted average shares outstanding, from the computation of diluted net income (loss) per share because including them would have had an anti-dilutive effect: Three Months Ended March 31, 2024 2023 Convertible senior notes 4,893,848 — Options to purchase common stock 577,604 3,292,968 Employee stock purchase plan 24,413 13,021 Restricted stock units 1,356 81,293 Restricted stock awards — 24,315 Warrants to purchase common stock — 14,440 5,497,221 3,426,037

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies Operating Leases The Company leases office, laboratory and manufacturing space under two non-cancelable operating leases. There have been no material changes to the Company’s leases during the three months ended March 31, 2024. 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, 2023. 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. Effective January 1, 2023, the Company instituted an employer matching program for the 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 months ended March 31, 2024 and 2023, the Company recorded expense of $ 0.6 million and $ 0.3 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 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 March 31, 2024 and December 31, 2023. 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 March 31, 2024 was $ 6.0 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.

Revenue

Revenue	3 Months Ended
Revenue	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue	12. Revenue 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 March 31, 2024 2023 OCS transplant revenue by country by organ(1)(2): United States Lung total revenue $ 4,706 $ 1,431 Heart total revenue 20,224 12,956 Liver total revenue 66,926 23,114 Total United States OCS transplant revenue 91,856 37,501 All other countries Lung revenue 960 251 Heart revenue 3,131 3,802 Total all other countries OCS transplant revenue 4,091 4,053 Total OCS transplant revenue $ 95,947 $ 41,554 (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 $ 0.9 million for the three months ended March 31, 2024 and none for the three months ended March 31, 2023 , is not included in this table. Significant Customers Significant customers are those that accounted for 10 % or more of the Company’s revenue or accounts receivable. For the three months ended March 31, 2024 and 2023 , no customer accounted for more than 10 % of revenue. As of March 31, 2024 and December 31, 2023 , no customer accounted for more than 10 % of accounts receivable. Payments to Customers In connection with its clinical trials, the Company makes payments to customers for reimbursement of clinical trial materials and customer’s costs incurred to execute specific clinical trial protocols related to the Company’s OCS products (reduction of revenue), and payments made to customers to obtain information related to post-approval studies or existing standard-of-care protocols unrelated to the Company's OCS products (operating expenses). For the three months ended March 31, 2024 and 2023, the Company did not record any adjustments to revenue related to such payments. For the three months ended March 31, 2024 and 2023, the Company recorded $ 0.3 million and $ 0.1 million, respectively, to research and development expense related to these costs.

Related Party Transactions

Related Party Transactions	3 Months Ended
Related Party Transactions	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	13. 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 March 31, 2024 and 2023 , for her services as an employee.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2024
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, 2023 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 March 31, 2024 and results of operations for the three months ended March 31, 2024 and 2023 and cash flows for the three months ended March 31, 2024 and 2023 have been made. The Company’s results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 .
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 and Significant Suppliers	Risk of Concentrations of Credit 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 March 31, 2024 and December 31, 2023, the Company had no allowance for credit losses. 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.
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 accompanying consolidated balance sheets, and the fair value of the Notes is presented at each reporting period for disclosure purposes only (see Note 8)
Spare Parts Inventory	Spare Parts Inventory Spare parts are used in aviation operations and are generally not for sale. Spare parts inventory is comprised of repairable and expendable spare aircraft parts, which are valued at the lower of cost or net realizable value, using the specific identification method. Storage costs and miscellaneous materials and supplies costs related to inventory or to support flight equipment are expensed as incurred. As of March 31, 2024, spare parts inventory of $ 0.6 million is included within prepaid expenses and other current assets on the accompanying consolidated balance sheets. The Company had no spare parts inventory as of December 31, 2023. The Company determines, based on the evidence that exists, whether or not it is appropriate to maintain a reserve for excess and obsolete spare parts inventory. The reserve is based on historical experience related to the disposal of inventory due to damage, physical deterioration, obsolescence, or other causes. As of March 31, 2024 and December 31, 2023, the Company had no allowance for spare parts excess and obsolescence
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.
Foreign Currency Translation	Foreign Currency Translation The functional currency of each of the Company’s foreign subsidiaries is the currency of the local country. Assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars using the period-end exchange rates, and income and expense items are translated into U.S. dollars using average exchange rates in effect during each period. The effects of these foreign currency translation adjustments are included in accumulated other comprehensive income (loss), a separate component of stockholders’ equity. The Company also incurs transaction gains and losses resulting from intercompany transactions as well as transactions with customers or vendors denominated in currencies other than the functional currency of the legal entity in which the transaction is recorded. Realized and unrealized foreign currency transaction gains (losses) are included in the consolidated statements of operations as a component of other income (expense) and totaled $( 0.2 ) million and $ 0.1 million, for the three months ended March 31, 2024 and 2023 , respectively.
Recently Issued Accounting Pronouncements	Recently issued accounting pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently assessing the impact of the adoption of this guidance. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public entities, on an annual basis, to provide disclosure of specific categories in their tax rate reconciliations, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently assessing the impact of the adoption of this guidance.

Acquisition of Summit (Tables)

Acquisition of Summit (Tables)	3 Months Ended
Acquisition of Summit (Tables)	Mar. 31, 2024
Business Combinations [Abstract]
Summary of Assets Acquired and Liabilities Assumed	The following table summarizes the preliminary allocation of the purchase price (in thousands): Assets Acquired and Liabilities Assumed: Accounts receivable $ 2,089 Other current assets 1,040 Property, plant and equipment 5,922 Right-of-use asset 288 Intangible assets 2,430 Goodwill 11,990 Total assets acquired 23,759 Accounts payable and other current liabilities ( 6,917 ) Deferred tax liabilities ( 1,660 ) Operating lease liabilities ( 288 ) Total allocation of purchase price consideration, $ 14,894

Inventory (Tables)

Inventory (Tables)	3 Months Ended
Inventory (Tables)	Mar. 31, 2024
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventory consisted of the following (in thousands): March 31, 2024 December 31, 2023 Raw materials $ 25,520 $ 25,823 Work-in-process 4,525 3,806 Finished goods 18,496 14,606 $ 48,541 $ 44,235

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	3 Months Ended
Property, Plant and Equipment, Net (Tables)	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment, net consisted of the following (in thousands): March 31, 2024 December 31, 2023 Transplant aircraft $ 181,236 $ 141,855 Flight school aircraft 3,484 3,484 OCS Consoles 15,369 14,491 Manufacturing equipment 7,669 6,898 Computer equipment and software 3,283 3,021 Laboratory equipment 2,344 1,875 Office, trade show and training equipment 4,200 4,006 Leasehold improvements 13,938 13,354 Construction-in-progress 8,397 6,250 239,920 195,234 Less: Accumulated depreciation and amortization ( 25,499 ) ( 21,293 ) $ 214,421 $ 173,941

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
Goodwill and Intangible Assets (Tables)	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Acquired Intangible Assets	Acquired intangible assets consisted of the following (in thousands): March 31, 2024 Weighted Average Useful Life Gross Amount Accumulated Amortization Carrying Value (in years) Customer relationship 12 $ 2,320 $ 121 $ 2,199 Other 12 110 6 104 $ 2,430 $ 127 $ 2,303 December 31, 2023 Weighted Average Useful Life Gross Amount Accumulated Amortization Carrying Value (in years) Customer relationship 12 $ 2,320 $ 73 $ 2,247 Other 12 110 3 107 $ 2,430 $ 76 $ 2,354
Future Amortization Expense of Intangible Assets	Future amortization expense of the intangible assets as of March 31, 2024 is expected to be as follows (in thousands): Year Ending December 31, 2024 (nine months) $ 152 2025 203 2026 203 2027 203 2028 203 Thereafter 1,339 $ 2,303

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
Accrued Expenses and Other Current Liabilities (Tables)	Mar. 31, 2024
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): March 31, 2024 December 31, 2023 Accrued payroll and related expenses $ 16,413 $ 20,300 Accrued transportation costs 4,902 4,381 Accrued research, development and clinical trials expenses 2,479 1,771 Accrued other 13,058 11,769 $ 36,852 $ 38,221

Long-term Debt and Financing _2

Long-term Debt and Financing Arrangements (Tables)	3 Months Ended
Long-term Debt and Financing Arrangements (Tables)	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Notes	The Notes consisted of the following (in thousands): March 31, 2024 December 31, 2023 Principal amount of convertible senior notes $ 460,000 $ 460,000 Less: Current portion of convertible senior notes — — Convertible senior notes, net of current portion 460,000 460,000 Debt discount, net of accretion ( 12,165 ) ( 12,860 ) Convertible senior notes, net of discount and current portion $ 447,835 $ 447,140
Schedule of Long-Term Debt Instruments	Long-term debt consisted of the following (in thousands): March 31, 2024 December 31, 2023 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 ( 859 ) ( 936 ) Long-term debt, net of discount and current portion $ 59,141 $ 59,064

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
Stock-Based Compensation (Tables)	Mar. 31, 2024
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 March 31, 2024 2023 Cost of revenue $ 364 $ 49 Research, development and clinical trials expenses 878 518 Selling, general and administrative expenses 5,628 3,354 $ 6,870 $ 3,921

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	3 Months Ended
Net Income (Loss) per Share (Tables)	Mar. 31, 2024
Earnings Per Share [Abstract]
Reconciliation of Numerators and Denominators of Basic and Dilutive Net Income (Loss) per Common Share Computations	A reconciliation of the numerators and the denominators of the basic and dilutive net income (loss) per common share computations are as follows (in thousands, except share and per share amounts): Three Months Ended March 31, 2024 2023 Numerator: Net income (loss) $ 12,197 $ ( 2,636 ) Denominator: Weighted average basic common shares outstanding 32,760,190 32,260,267 Effect of dilutive securities: Options to purchase common stock 1,773,345 — Restricted stock units 126,797 — Warrants to purchase common stock 11,379 — Restricted stock awards 7,184 — Weighted average dilutive common shares outstanding 34,678,895 32,260,267 Net income (loss) per share: Basic $ 0.37 $ ( 0.08 ) Diluted $ 0.35 $ ( 0.08 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The Company excluded the following potential common shares, presented based on weighted average shares outstanding, from the computation of diluted net income (loss) per share because including them would have had an anti-dilutive effect: Three Months Ended March 31, 2024 2023 Convertible senior notes 4,893,848 — Options to purchase common stock 577,604 3,292,968 Employee stock purchase plan 24,413 13,021 Restricted stock units 1,356 81,293 Restricted stock awards — 24,315 Warrants to purchase common stock — 14,440 5,497,221 3,426,037

Revenue (Tables)

Revenue (Tables)	3 Months Ended
Revenue (Tables)	Mar. 31, 2024
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 March 31, 2024 2023 OCS transplant revenue by country by organ(1)(2): United States Lung total revenue $ 4,706 $ 1,431 Heart total revenue 20,224 12,956 Liver total revenue 66,926 23,114 Total United States OCS transplant revenue 91,856 37,501 All other countries Lung revenue 960 251 Heart revenue 3,131 3,802 Total all other countries OCS transplant revenue 4,091 4,053 Total OCS transplant revenue $ 95,947 $ 41,554 (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 $ 0.9 million for the three months ended March 31, 2024 and none for the three months ended March 31, 2023 , 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	Mar. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Cash	$ 350,217	$ 394,812

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2024 USD ($) Segment	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Allowance for credit losses	$ 0		$ 0
Number of operating segments \| Segment	1
Prepaid expenses and other current assets	$ 7,606,000		8,031,000
Other Income (Expense) [Member]
Foreign currency transaction gains (losses)	$ (200,000)	$ 100,000
Convertible Senior Notes Due 2028 [Member]
Debt instrument, interest rate	1.50%
Spare Parts Inventory [Member]
Prepaid expenses and other current assets	$ 600,000		$ 0

Acquisition of Summit - Additio

Acquisition of Summit - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Aug. 16, 2023	Sep. 30, 2023	Dec. 31, 2023
Business Acquisition [Line Items]
Goodwill adjustments			$ 300,000
Summit [Member]
Business Acquisition [Line Items]
Acquisition date	Aug. 16, 2023
Preliminary purchase consideration	$ 14,894,000
Upfront cash payment	18,000,000
Intangible assets	2,430,000
Goodwill resulting from the acquisition deductible for tax purposes	0
Tax benefit		$ 1,700,000
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	Mar. 31, 2024	Dec. 31, 2023	Aug. 16, 2023
Business Acquisition [Line Items]
Goodwill	$ 11,990	$ 11,990
Summit [Member]
Business Acquisition [Line Items]
Accounts receivable			$ 2,089
Other current assets			1,040
Property, plant and equipment			5,922
Right-of-use asset			288
Intangible assets			2,430
Goodwill	$ 12,000	$ 12,000	11,990
Total assets acquired			23,759
Accounts payable and other current liabilities			(6,917)
Deferred tax liabilities			(1,660)
Operating lease liabilities			(288)
Total allocation of purchase price consideration, net of cash acquired			$ 14,894

Inventory - Schedule of Invento

Inventory - Schedule of Inventory, Current (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials	$ 25,520	$ 25,823
Work-in-process	4,525	3,806
Finished goods	18,496	14,606
Inventory, net	$ 48,541	$ 44,235

Property, Plant and Equipment_3

Property, Plant and Equipment, Net - Schedule of Property, Plant and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 239,920	$ 195,234
Less: Accumulated depreciation and amortization	(25,499)	(21,293)
Property, plant and equipment, net	214,421	173,941
Transplant Aicraft [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	181,236	141,855
Flight School Aircraft [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,484	3,484
OCS Consoles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	15,369	14,491
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,669	6,898
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,283	3,021
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,344	1,875
Office, Trade Show and Training Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,200	4,006
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	13,938	13,354
Construction-In-Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 8,397	$ 6,250

Property, Plant and Equipment_4

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 4,302	$ 1,287

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Aug. 16, 2023
Goodwill [Line Items]
Carrying amount of goodwill	$ 11,990,000	$ 11,990,000
Impairments to goodwill	0
Amortization expense of intangible assets	100,000
Summit [Member]
Goodwill [Line Items]
Carrying amount of goodwill	$ 12,000,000	$ 12,000,000	$ 11,990,000

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Acquired Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 2,430	$ 2,430
Accumulated Amortization	127	76
Carrying Value	$ 2,303	$ 2,354
Customer Relationship [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)	12 years	12 years
Gross Amount	$ 2,320	$ 2,320
Accumulated Amortization	121	73
Carrying Value	$ 2,199	$ 2,247
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)	12 years	12 years
Gross Amount	$ 110	$ 110
Accumulated Amortization	6	3
Carrying Value	$ 104	$ 107

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Future Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
2024 (nine months)	$ 152
2025	203
2026	203
2027	203
2028	203
Thereafter	1,339
Carrying Value	$ 2,303	$ 2,354

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued payroll and related expenses	$ 16,413	$ 20,300
Accrued transportation costs	4,902	4,381
Accrued research, development and clinical trials expenses	2,479	1,771
Accrued other	13,058	11,769
Accrued expenses and other liabilities current	$ 36,852	$ 38,221

Long-term Debt and Financing _3

Long-term Debt and Financing Arrangements - Schedule of Notes (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Convertible senior notes, net of discount and current portion	$ 447,835	$ 447,140
Convertible Debt [Member]
Debt Instrument [Line Items]
Principal amount	460,000	460,000
Net of current portion	460,000	460,000
Debt discount, net of accretion	$ (12,165)	$ (12,860)

Long-term Debt and Financing _4

Long-term Debt and Financing Arrangements - Convertible Senior Notes - Additional Information (Detail)			3 Months Ended
	May 11, 2023 USD ($) TradingDays $ / shares shares	May 08, 2023	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Estimated fair value of convertible senior notes			$ 506,400,000
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
Percentage of cash coupon of notes and amortization of the debt issuance costs			1.50%
Proceeds from Convertible Debt	$ 393,300,000
Debt instrument, frequency of periodic payment	semiannually
Capped call transaction costs net	$ 52,100,000
Purchase discounts and other debt issuance costs	$ 14,600,000
Debt instrument, interest rate	1.50%
Debt instrument interest payable description			The Notes bear interest at a rate of 1.50% per year and interest is payable semiannually in arrears on June 1 and December 1 of each year.
Conversion of per principal amount of notes	$ 1,000
Average effective interest rate			2.10%
Convertible Senior Notes [Member] \| Used To Fund Capped Call Transactions [Member]
Debt Instrument [Line Items]
Proceeds from Convertible Debt	$ 52,100,000
Convertible Senior Notes [Member] \| Per One Thousand Dollars [Member]
Debt Instrument [Line Items]
Initial conversion rate shares of common stock \| shares	10.6388
Convertible Senior Notes [Member] \| Before March 1, 2028 [Member]
Debt Instrument [Line Items]
Conversion of per principal amount of notes	$ 1,000
Debt instrument, redemption period, end date	Mar. 01, 2028
Number of trading days \| TradingDays	5
Number of consecutive trading days \| TradingDays	10
Convertible Senior Notes [Member] \| Calendar Quarter Ending on September 30, 2023 but Before March 1, 2028 [Member]
Debt Instrument [Line Items]
Debt instrument, redemption period, start date	Sep. 30, 2023
Debt instrument, redemption period, end date	Mar. 01, 2028
Number of trading days \| TradingDays	20
Number of consecutive trading days \| TradingDays	30
Conversion price	130%
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) - Capped Calls [Member] $ in Millions		3 Months Ended
	May 11, 2023 USD ($)	Mar. 31, 2024 TradingDays $ / shares shares
Debt Instrument [Line Items]
Purchases of capped calls related to convertible senior notes \| $	$ 52.1
Initial conversion price/rate		$ 94
Capped calls, initial cap price per share		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	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Long-term debt, net of discount and current portion	$ 59,141	$ 59,064
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	(859)	(936)
Long-term debt, net of discount and current portion	$ 59,141	$ 59,064

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
	Jul. 31, 2022	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 60,000		$ 60,000
Canadian Imperial Bank of Commerce [Member]
Debt Instrument [Line Items]
Interest rate effective percentage		7.30%
Average effective interest rate		7.80%	7.30%
Interest expense, debt		$ 1,200	$ 1,100
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), as defined, for the trailing four month period (only if EBITDA is negative) and (ii) $10.0 million, and (y) a requirement to maintain total net revenue of at least 75% of the level set forth in the total revenue plan presented to CIBC.
Minimum liquidity covenant amount		$ 10,000
Minimum percentage to maintain total net revenue set forth in total revenue plan presented		75%
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] \| Interest Rate Option Two \| Term Loan [Member]
Debt Instrument [Line Items]
LIBOR rate	1%
Canadian Imperial Bank of Commerce [Member] \| Credit Agreement [Member] \| 12 to 24 Months After Closing Date [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee percentage	1%
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
	Nov. 02, 2023	May 25, 2023	Apr. 15, 2019	Mar. 31, 2024	Mar. 31, 2023	Aug. 31, 2021
Unrecognized compensation cost related to unvested employee and director stock-based awards				$ 73.4
Weighted average period for unrecognized compensation cost				2 years 7 months 6 days
Common Stock
Number of shares issued				9,506	14,135
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				929,897
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				255,053
Purchase price of common stock, percent			85%
Number of shares issued				9,506
2021 Inducement Plan [Member] \| Common Stock
Share-based compensation arrangement by share-based payment award, number of shares authorized						1,000,000
Share-based compensation arrangement by sharebased payment award, number of additional shares authorized	500,000
Share based compensation arrangement by share based payment award number of shares available for grant				564,538
2019 Plan and 2021 Inducement Plan [Member] \| Common Stock
Options granted				304,976
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value				$ 53.48
2019 Plan and 2021 Inducement Plan [Member] \| Restricted stock units [Member]
Shares granted				198,860
Share-based compensation arrangement by share-based payment award, grants in period, weighted average grant date fair value				$ 82.77

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Allocated Share-based Compensation Expense	$ 6,870	$ 3,921
Cost of revenue [Member]
Allocated Share-based Compensation Expense	364	49
Research, development and clinical trials expenses [Member]
Allocated Share-based Compensation Expense	878	518
Selling, general and administrative expenses [Member]
Allocated Share-based Compensation Expense	$ 5,628	$ 3,354

Net Income (Loss) per Share - R

Net Income (Loss) per Share - Reconciliation of Numerators and Denominators of Basic and Dilutive Net Income (Loss) per Common Share Computations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss)	$ 12,197	$ (2,636)
Weighted average common shares outstanding, basic	32,760,190	32,260,267
Weighted average common shares outstanding, diluted	34,678,895	32,260,267
Net income (loss) per share, basic	$ 0.37	$ (0.08)
Net income (loss) per share, diluted	$ 0.35	$ (0.08)
Warrants to purchase common stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities	11,379
Options to purchase common stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities	1,773,345
Restricted stock units [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities	126,797
Restricted stock awards [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities	7,184

Net Income (Loss) per Share - S

Net Income (Loss) per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	5,497,221	3,426,037
Convertible senior notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	4,893,848
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	577,604	3,292,968
Employee stock purchase plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	24,413	13,021
Restricted stock units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	1,356	81,293
Restricted stock awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount		24,315
Warrants to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount		14,440

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		15 Months Ended
	Jan. 31, 2021	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024
Lessee operating lease description		two non-cancelable operating leases.
Defined contribution plan, contribution amount		$ 0.6	$ 0.3
Recorded unconditional purchase commitment, minimum quantity required	$ 9.5
Recorded unconditional purchase commitment, maturity year and month	2029-12
Remaining purchase commitment		$ 6		$ 6
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%

Revenue - Schedule of Net Reven

Revenue - Schedule of Net Revenue by Organ and Country (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue		$ 96,850	$ 41,554
OCS transplant revenue
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	95,947	41,554
OCS transplant revenue \| United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	91,856	37,501
OCS transplant revenue \| All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	4,091	4,053
Lung revenue [Member] \| OCS transplant revenue \| United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	4,706	1,431
Lung revenue [Member] \| OCS transplant revenue \| All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	960	251
Heart revenue [Member] \| OCS transplant revenue \| United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	20,224	12,956
Heart revenue [Member] \| OCS transplant revenue \| All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	3,131	3,802
Liver revenue [Member] \| OCS transplant revenue \| United States [Member]
Disaggregation Of Revenue [Line Items]
Total OCS transplant revenue	[1],[2]	$ 66,926	$ 23,114

[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 $ 0.9 million for the three months ended March 31, 2024 and none for the three months ended March 31, 2023 , 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
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 96,850,000	$ 41,554,000
Unrelated to OCS Transplant [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 900,000	$ 0

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Research development and clinical trials expenses	$ 0.3	$ 0.1
Customer Concentration Risk \| Revenue Benchmark \| Minimum [Member] \| Significant Customer Benchmark [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	10%	10%
Customer Concentration Risk \| Accounts Receivable \| Minimum [Member] \| Significant Customer Benchmark [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	10%		10%

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Director [Member]
Related Party Transaction [Line Items]
Compensation expense	$ 0.1	$ 0.1