View Filing Data

Research, development and clinical trials

^[1]

$ 23,604

$ 13,017

Cost of revenue

9,741

7,283

Gross profit

13,863

5,734

Operating expenses:

19,870

13,656

Selling, general and administrative

23,596

12,315

Total operating expenses

43,466

25,971

Loss from operations

(29,603)

(20,237)

Other income (expense):

Interest expense

(4,353)

(2,720)

Change in fair value of preferred stock warrant liability

(341)

(545)

Other income (expense), net

790

(213)

Total other expense, net

(3,904)

(3,478)

Loss before income taxes

(33,507)

(23,715)

Provision for income taxes

(40)

(41)

Net loss

$ (33,547)

$ (23,756)

Net loss per share attributable to common stockholders, basic and diluted

$ (2.36)

$ (17.48)

Weighted average common shares outstanding, basic and diluted

14,204,787

1,358,694

[1]	Net revenue by country is categorized based on the location of the end customer.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (33,547)	$ (23,756)
Other comprehensive income (loss):
Foreign currency translation adjustment	45	41
Unrealized gains (losses) on marketable securities, net of tax of $0	54	7
Total other comprehensive income (loss)	99	48
Comprehensive loss	$ (33,448)	$ (23,708)

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

+ References + Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Statement Of Income And Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ 0	$ 0

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Convertible Preferred Stock [Member]	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 30, 2017	$ (168,724)	$ 186,519	$ 1	$ 143,604	$ (149)	$ (312,180)
Balance, Shares at Dec. 30, 2017		50,404,140	1,330,693
Issuance of common stock upon the exercise of common stock options	46			46
Issuance of common stock upon the exercise of common stock options, Shares			67,107
Abandonment of shares of common stock by stockholders, Shares			(307)
Stock-based compensation expense	144			144
Foreign currency translation adjustment	41				41
Unrealized gains (losses) on marketable securities	7				7
Net loss	(23,756)					(23,756)
Balance at Dec. 29, 2018	(192,242)	$ 186,519	$ 1	143,794	(101)	(335,936)
Balance, Shares at Dec. 29, 2018		50,404,140	1,397,493
Conversion of convertible preferred stock into common stock upon initial public offering	186,519	$ (186,519)	$ 186,519
Conversion of convertible preferred stock into common stock upon initial public offering, Shares		(50,404,140)	13,119,424
Conversion of TransMedics' common stock into TransMedics Group's common stock upon corporate reorganization			$ 143,859	(143,859)
Conversion of preferred stock warrants into common stock warrants upon initial public offering	1,239		1,239
Issuance of common stock in initial public offering,net of discounts and issuance costs of $5,966	91,401		$ 91,401
Issuance of common stock in initial public offering,net of discounts and issuance costs of $5,966, Shares			6,543,500
Issuance of common stock upon the exercise of common stock options	$ 202		$ 194	8
Issuance of common stock upon the exercise of common stock options, Shares	124,226		124,107
Stock-based compensation expense	$ 854		$ 797	$ 57
Settlement of accrued financing fees	124		124
Foreign currency translation adjustment	45				45
Unrealized gains (losses) on marketable securities	54				54
Net loss	(33,547)					(33,547)
Balance at Dec. 28, 2019	$ 54,649		$ 424,134		$ (2)	$ (369,483)
Balance, Shares at Dec. 28, 2019			21,184,524

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 28, 2019 USD ($)
Statement Of Stockholders Equity [Abstract]
Discounts and issuance costs of stock issued	$ 5,966

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Cash flows from operating activities:
Net loss	$ (33,547)	$ (23,756)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	1,222	769
Stock-based compensation expense	854	144
Change in fair value of preferred stock warrant liability	341	545
Non-cash interest and end of term accretion expense	475	177
Net amortization (accretion) of premiums (discounts) on marketable securities	(205)	9
Loss on extinguishment of debt		305
Unrealized foreign currency transaction losses	200	150
Changes in operating assets and liabilities:
Accounts receivable	(3,166)	(2,513)
Inventory	(4,121)	(2,699)
Prepaid expenses and other current assets	250	(1,355)
Accounts payable	3,443	164
Accrued expenses and other current liabilities	2,453	2,338
Deferred revenue	(136)	67
Deferred rent	(349)	(329)
Net cash used in operating activities	(32,286)	(25,984)
Cash flows from investing activities:
Purchases of property and equipment	(165)	(418)
Purchases of marketable securities	(82,371)
Proceeds from sales and maturities of marketable securities	22,035	12,725
Net cash (used in) provided by investing activities	(60,501)	12,307
Cash flows from financing activities:
Proceeds from issuance of long-term debt, net of issuance costs		33,436
Repayments of long-term debt		(9,076)
Proceeds from issuance of common stock in initial public offering, net of underwriting discounts and commissions	97,367
Payments of initial public offering and other financing costs	(4,846)	(2,342)
Proceeds from issuance of common stock upon exercise of stock options	202	46
Net cash provided by financing activities	92,723	22,064
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(85)	(82)
Net (decrease) increase in cash, cash equivalents and restricted cash	(149)	8,305
Cash, cash equivalents and restricted cash, beginning of period	20,741	12,436
Cash, cash equivalents and restricted cash, end of period	20,592	20,741
Supplemental disclosure of cash flow information:
Cash paid for interest	3,877	2,401
Supplemental disclosure of non-cash investing and financing activities:
Conversion of convertible preferred stock to common stock upon initial public offering	186,519
Transfers of inventory to property and equipment	2,146	1,393
Reclassification of warrant liability to equity upon initial public offering	1,239
Purchases of property and equipment included in accounts payable	169
Offering costs included in accounts payable and accrued expenses	120	$ 1,041
Settlement of accrued financing fee	$ 124

Nature of the Business and Basis of Presentation

12 Months Ended

Dec. 28, 2019

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. (the “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 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. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s technology will be obtained, that any products will obtain necessary government regulatory approval or that any approved products will be commercially viable. The Company operates in an environment of rapid change in technology and competition from other medical device companies.

The Corporate Reorganization

On May 6, 2019, immediately prior to the closing of the Company’s initial public offering (the “IPO”), the Company completed a corporate reorganization whereby TransMedics, the direct parent of TransMedics Group prior to the corporate reorganization, became a direct, wholly-owned subsidiary of TransMedics Group pursuant to the merger of TMDX, Inc., a direct, wholly-owned subsidiary of TransMedics Group prior to the corporate reorganization, with and into TransMedics, with TransMedics as the surviving corporation. Pursuant to the terms of an agreement and plan of merger and reorganization, as a result of the merger, each outstanding share of common stock of TransMedics was converted into shares of common stock of TransMedics Group on a 3.5-for-one basis, each outstanding share of convertible preferred stock of TransMedics was converted into shares of common stock of TransMedics Group based on the conversion ratio of each individual series of preferred stock, as defined in the certificate of incorporation of TransMedics prior to the conversion, and the 3.5-for-one ratio on which shares of common stock of TransMedics were converted into common stock of TransMedics Group; each outstanding option to purchase shares of common stock of TransMedics was converted into an outstanding option to purchase shares of common stock of TransMedics Group adjusted on a 3.5-for-one basis, with a corresponding adjustment to the exercise price; and each outstanding warrant to purchase shares of preferred stock of TransMedics was converted into a warrant to purchase shares of common stock of TransMedics Group adjusted on a 3.5-for-one basis, with a corresponding adjustment to the exercise price. This is referred to as the “Corporate Reorganization.”

All share and per share amounts for all periods presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect the 3.5-for-one conversion ratio applied to common stock in the Corporate Reorganization.

Immediately following the Corporate Reorganization, (i) TransMedics Group became a holding company with no material assets other than 100% of the equity interests in TransMedics, (ii) the holders of capital stock in TransMedics became shareholders of TransMedics Group and (iii) the historical consolidated financial statements of TransMedics became the historical consolidated financial statements of TransMedics Group because the Corporate Reorganization was accounted for as a reorganization of entities under common control. Prior to the Corporate Reorganization, TransMedics Group had not conducted any activities other than in connection with its formation and in preparation for the IPO and had no material assets other than 100% of the equity interests in TMDX, Inc.

On May 6, 2019, the Company completed its IPO, pursuant to which it issued and sold 6,543,500 shares of common stock, inclusive of 853,500 shares sold by the Company pursuant to the full exercise of the underwriters’ option to purchase additional shares. The aggregate net proceeds received by the Company from the IPO were $91.4 million, after deducting underwriting discounts and commissions as well as other offering costs of $6.0 million.

The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has incurred recurring losses since inception, including net losses attributable to the Company of $33.5 million for the fiscal year end ended December 28, 2019 and $23.8 million for the fiscal year ended December 29, 2018. As of December 28, 2019, the Company had an accumulated deficit of $369.5 million. The Company expects to continue to generate operating losses in the foreseeable future.

The Company believes that its existing cash, cash equivalents, and marketable securities of $80.7 million as of December 28, 2019 will be sufficient to fund operations, capital expenditures, and debt service payments for at least the next twelve months following the filing of this Annual Report on Form 10-K.

The Company may need to seek additional funding through equity financings, debt financings or strategic alliances. The Company may not be able to obtain financing on acceptable terms, or at all, and the terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders.

If the Company is unable to obtain funding, the Company will be required to delay, reduce or eliminate some or all of its research and development programs, product expansion or commercialization efforts, or the Company may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

Basis of Presentation

The Company’s fiscal year ends on the last Saturday in December, and the Company reports fiscal years using a 52/53-week convention. Under this convention, certain fiscal years contain 53 weeks. Each fiscal year is typically composed of four 13-week fiscal quarters, but in years with 53 weeks, the fourth quarter is a 14-week period. The fiscal year ended December 28, 2019 and December 29, 2018 included 52 weeks.

The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). 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 Accounting Policies

12 Months Ended

Dec. 28, 2019

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, revenue recognition, the valuation of inventory, the valuation of common stock prior to the IPO, the valuation of stock-based awards and the valuation of the preferred stock warrant liability. 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. Actual results may differ from those estimates or assumptions.

Risk of Concentrations of Credit, Significant Customers and Significant Suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities and accounts receivable. The Company has not experienced any other-than-temporary losses with respect to its cash, cash equivalents and marketable securities and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities as of December 28, 2019 consisted of U.S. Treasury securities and U.S. government agency bonds. The Company had no marketable securities as of December 29, 2018.

Significant customers are those that accounted for 10% or more of the Company’s total revenue or accounts receivable (see Note 16).

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. Although the Company seeks to reduce dependence on those limited sources of suppliers and manufacturers, the partial or complete loss of certain of these sources could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships.

Deferred Offering Costs

The Company capitalizes certain legal, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of common stock generated as a result of the offering. Should the in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations. The Company recorded deferred offering costs of $3.4 million as of December 29, 2018. Upon closing of the IPO on May 6, 2019, these deferred offering costs were included in the $6.0 million issuance costs classified to stockholders’ equity (deficit) and recorded against the proceeds from the offering.

Deferred Financing Costs

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

Cash Equivalents

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

Restricted Cash

As of December 28, 2019 and December 29, 2018, the Company maintained two letters of credit totaling $0.5 million for the benefit of the landlord of its leased property. The Company was required to maintain a separate cash balance of $0.5 million to secure the letters of credit. Related to this separate cash balance, the Company classified $0.5 million as restricted cash (non-current) on its consolidated balance sheets as of December 28, 2019 and December 29, 2018. The Company’s cash, cash equivalents and restricted cash was $20.6 million and $20.7 million for the years ended December 28, 2019 and December 29, 2018, respectively.

Accounts Receivable

Accounts receivable are presented net of a provision for doubtful accounts, which is an estimate of amounts that may not be collectible. The Company performs ongoing credit evaluations of its customers and, if necessary, provides an allowance for doubtful accounts and expected losses. The Company writes off accounts receivable against the allowance when it determines a balance is uncollectible and no longer actively pursues collection of the receivable. As of December 28, 2019 and December 29, 2018, the Company had no allowance for doubtful accounts. During the fiscal years ended December 28, 2019 and December 29, 2018, the Company did not record any provisions for doubtful accounts and did not write off any accounts receivable balances.

Property and Equipment

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

		Estimated Useful Life
Manufacturing equipment		5 years
OCS Consoles loaned to customers		5 years
Computer equipment and software		3 years
Laboratory equipment		3 years
Office and trade show equipment		5 years
Leasehold improvements		Shorter of term of lease or 15 years

Costs incurred for OCS Consoles are recorded as inventory unless and until the Company determines that an OCS Console will be loaned to a customer for its use. When an OCS Console is loaned to a customer, the Company reclassifies the cost of the OCS Console from inventory to property and equipment and begins to depreciate the loaned OCS Console over its estimated life. Related depreciation expense for the loaned OCS Console is classified as a cost of revenue. If an OCS Console is returned to the Company, it will continue to be classified as property and equipment and depreciated over its remaining useful life. The Company retains title to all OCS Consoles loaned to customers.

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

Impairment of Long-Lived Assets

Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized in loss from operations when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value. The Company did not record any impairment losses on long-lived assets during the fiscal years ended December 28, 2019 and December 29, 2018

Software Development Costs

The Company incurs costs to develop computer software that is embedded in the hardware components of the Company’s OCS Console and OCS Perfusion Sets. Research and development costs related to this software are expensed as incurred, except for costs of internally developed or externally purchased software that qualify for capitalization. Software development costs incurred subsequent to the establishment of technological feasibility, but prior to the general release of the product, are capitalized and, upon general release, are amortized based upon the pattern in which economic benefits related to such assets are realized. Due to the short time period between achieving technological feasibility and product release and the insignificant amount of costs incurred during such periods, the Company did not capitalize any software development costs during the fiscal years ended December 28, 2019 and December 29, 2018.

Inventory

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

At the end of each reporting period, the Company assesses whether losses should be accrued on long-term manufacturing purchase commitments in accordance with Accounting Standards Codification (“ASC”) 330, Inventory, which requires that losses that are expected to arise from firm, noncancelable and unhedged commitments for the future purchase of inventory, measured in the same way as inventory losses, should be recognized in the current period in the statements of operations unless they are deemed recoverable through firm sales contacts or when there are other circumstances that reasonably assure continuing sales without price decline. As of the end of each reporting period presented in the accompanying consolidated financial statements, the Company did not identify any potential losses arising from remaining future purchase commitments as compared to estimated future customer sales through the remainder of the term of the manufacturing purchase commitment and, as a result, did not recognize any loss provision for future-period remaining purchase commitments for the fiscal year ended December 28, 2019.

Deferred Rent

The Company’s lease agreements include payment escalations, rent holidays and other lease incentives, which are accrued or deferred as appropriate such that rent expense for each lease is recognized on a straight-line basis over the respective lease term. Adjustments for such items, consisting primarily of payment escalations, are recorded as deferred rent and amortized over the respective lease terms.

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 Company’s cash equivalents and marketable securities consisting of money market funds, U.S. Treasury securities and U.S. government agency bonds, and its preferred stock warrant liability are carried at fair value, determined according to the fair value hierarchy described above (see Note 4). 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 at each balance sheet date due to its variable interest rate, which approximates a market interest rate.

Marketable Securities

The Company’s marketable securities (non-equity instruments) are classified as available-for-sale and are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity (deficit). Realized gains and losses and declines in value determined to be other than temporary are based on the specific identification method and are included as a component of other income (expense), net in the consolidated statements of operations.

The Company evaluates its marketable securities with unrealized losses for other-than-temporary impairment. When assessing marketable securities for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge recorded in the consolidated statements of operations. No such adjustments were necessary during the periods presented.

Classification of Convertible Preferred Stock

The Company’s previously issued convertible preferred stock (series A-1, B-1, C, D, E and F) is classified outside of stockholders’ equity (deficit) on the consolidated balance sheet because the holders of such shares had liquidation rights in the event of a deemed liquidation that, in certain situations, was not solely within the control of the Company.

Preferred Stock Warrant Liability

The Company classified warrants for the purchase of shares of its convertible preferred stock (see Notes 3 and 9) as a liability on its consolidated balance sheets as these warrants were freestanding financial instruments that could have required the Company to transfer assets upon exercise. The warrant liability was initially recorded at fair value upon the date of issuance of each warrant and was subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability were recognized as a component of other income (expense) in the consolidated statements of operations. On May 6, 2019, immediately prior to the closing of the IPO, these warrants were converted into warrants to purchase common stock and the fair value of the warrant liability at that time was reclassified to common stock. As a result, subsequent to the closing of the IPO, the Company no longer remeasures the fair value of the warrant liabilities at each reporting date.

Segment Information

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

Product Warranties

The Company provides a one-year warranty on its OCS Consoles and disposable sets and replaces or repairs any OCS Console or disposable set that does not function in accordance with the product specifications. OCS Consoles returned to the Company may be refurbished and redeployed. Estimated warranty costs are recorded at the time of shipment of the OCS Console or disposable set. Warranty costs are estimated based on the current expected product replacement or repair cost and expected replacement or repair rates based on historical experience. The Company evaluates its warranty accrual at the end of each reporting period and makes adjustments as necessary. As of December 28, 2019 and December 29, 2018, the warranty accrual was less than $0.1 million.

Revenue Recognition

The Company generates revenue primarily from sales of its single-use, organ-specific disposable sets (i.e., its organ-specific OCS Perfusion Sets sold together with its organ-specific OCS Solutions) used on its organ-specific OCS Consoles, each being a component of the Company’s OCS products. To a lesser extent, the Company also generates revenue from the sale of OCS Consoles to customers and from the implied rental of OCS Consoles loaned to customers at no charge. For each new transplant procedure, customers purchase an additional OCS disposable set for use on the customer’s existing organ-specific OCS Console.

The Company recognizes revenue from sales to customers applying the following five steps: (1) identification of the contract, or contracts, with a customer, (2) identification of the performance obligations in the contract, (3) determination of the transaction price, (4) allocation of the transaction price to the performance obligations in the contract, and (5) recognition of revenue when, or as, performance obligations are satisfied. Because all performance obligations of a customer order are delivered and recognized as revenue at the same time and because revenue allocated to performance obligations other than OCS disposable sets, such as implied rental income and service revenue, is insignificant, all components of revenue from customer arrangements are classified as a single category of revenue in the Company’s consolidated statements of operations.

Substantially all of the Company’s customer contracts have multiple-performance obligations that contain deliverables consisting of OCS Perfusion Sets and OCS Solutions. In some of those customer contracts, the deliverables also include an OCS Console, whether sold or loaned to the customer. The Company evaluates each promise within a multiple-performance obligation arrangement to determine whether it represents a distinct performance obligation. A performance obligation is distinct if (1) the product or service is separately identifiable from other promises in the contract and (2) the customer can benefit from the product or service on its own or with other resources that are readily available to the customer.

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

Some of the Company’s revenue has been generated from products sold in conjunction with the clinical trials conducted for the Company’s OCS products, under arrangements referred to as customer clinical trial agreements. Under most of these customer clinical trial agreements, the Company places an organ-specific OCS Console at the customer site for its use free of charge for the duration of the clinical trial, and the customer separately purchases from the Company the OCS disposable sets used in each transplant procedure during the clinical trial. When the Company loans the OCS Console to the customer, it retains title to the console at all times and does not require minimum purchase commitments from the customer related to any OCS products. In such cases, the Company invoices the customer for OCS disposable sets based on customer orders received for each new transplant procedure and the prices set forth in the customer agreement. Over time, the Company typically recovers the cost of the loaned OCS Console through the customer’s continued purchasing and use of additional OCS disposable sets. For these reasons, the Company has determined that part of the arrangement consideration for the disposable set is an implied rental payment for use of the OCS Console.

When the Company’s customer arrangements have multiple-performance obligations that contain a loan of an OCS Console for the customer’s use at its customer site as well as OCS disposable sets that are delivered simultaneously, the Company allocates the arrangement consideration between the lease deliverables (i.e., the OCS Console) and non-lease deliverables (i.e., the OCS disposable sets) based on the relative estimated standalone selling price (“SSP”) of each distinct performance obligation. To date, the amounts allocated to lease deliverables have been insignificant. In determining SSP, the Company maximizes observable inputs and consider a number of data points, including: (1) the pricing of standalone sales (in instances where available), (2) the pricing established by management when setting prices for deliverables that are intended to be sold on a standalone basis, (3) contractually stated prices for deliverables that are intended to be sold on a standalone basis, and (4) other pricing factors, such as the geographical region in which the products are sold and expected discounts based on the customer size and type.

Revenue is recognized when control of the OCS product or products is transferred to the customer in an amount that reflects the consideration the Company expects to be entitled to in exchange for the product or products.

Performance Obligations

The primary performance obligations in the Company’s customer arrangements from which it derives revenue are as follows:

•

OCS Console — The OCS Console is a medical device that houses and controls the function of the OCS. The performance obligation of the OCS Console includes customer training and equipment set-up. Revenue for each OCS Console is recognized at the point in time at which control is transferred to the customer, which is typically only after the console has arrived at the customer site and the training and equipment set-up have been completed by the Company because the customer cannot benefit from the OCS Console without the training and equipment set-up having been completed. At that time, the Company believes that the customer has the significant risks and rewards of ownership.

•

OCS Perfusion Set — The OCS Perfusion Set is a single-use disposable set that stores the organ and circulates blood. Revenue for each OCS Perfusion Set is recognized at the point in time at which control is transferred to the customer, which is when title transfers to the customer in connection with delivery. In most of the Company’s customer arrangements, title to the OCS Perfusion Set transfers when the OCS Perfusion Set arrives at the customer site. In limited instances, title transfers upon shipment to the customer by the Company.

•

OCS Solutions — The OCS Solutions are a set of nutrient-enriched solutions to optimize the organ’s condition outside the human body. Revenue for each OCS Solution is recognized at the point in time at which control is transferred to the customer, which is when title transfers to the customer in connection with delivery. In most of the Company’s customer arrangements, title to the OCS Solutions transfers when the OCS Solutions arrive at the customer site. In limited instances, title transfers upon shipment to the customer by the Company.

Payments Made to Customers

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

The Company has determined that the payments made to the customer for reimbursement of clinical trial materials and customer’s costs incurred to execute specific clinical trial protocols related to the Company’s OCS products do not provide the Company with a distinct good or service transferred by the customer, and therefore such payments are recorded as a reduction of revenue from the customer in the Company’s consolidated statements of operations. Reductions of revenue related to such payments made to customers for reimbursements are recognized when the Company recognizes the revenue for the sale of its OCS disposable sets. The Company recorded the reimbursable clinical costs as a reduction of revenue of $2.2 million and $1.6 million for the fiscal years ended December 28, 2019 and December 29, 2018, respectively, as presented below in disaggregated revenue.

The Company has also determined that payments made to customers to obtain information related to post-approval studies or existing standard-of-care protocols (i.e., unrelated to the Company’s OCS products) do meet the criteria to be classified as a cost because the Company receives a distinct good or service transferred by the customer separate from the customer’s purchase of the Company’s OCS products and the consideration paid represents the fair value of the distinct good or service received by the Company. As a result, these payments made to the customers for information related to post-approval studies or standard-of-care protocols are recorded as research, development, and clinical trials expenses. The Company recorded payments made to customers related to post-approval studies and for documentation related to existing standard-of-care protocols of $1.2 million and $0.6 million for the fiscal years ended December 28, 2019 and December 29, 2018, respectively, as research, development, and clinical trials expenses.

Variable Consideration

Revenue is reported net of any taxes assessed by a governmental authority that are directly imposed on a revenue-producing transaction (e.g., sales, use, and value added taxes). The Company only includes estimated variable amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved.

Revenue from reimbursements of out-of-pocket expenses, including travel, lodging, and meals, is accounted for as variable consideration.

The Company does not consider shipping to be a contract performance obligation. The Company records shipping costs billed to customers as revenue and records the associated costs incurred by the Company for those items as cost of revenue.

Contract Assets and Liabilities

The Company recognizes a receivable at the point in time at which it has an unconditional right to payment. Such receivables are not contract assets. Payment terms for customer orders, including for each of the Company’s primary performance obligations, are typically 30 days for customers in the United States and 30 to 90 days for customers in non-U.S. markets, and such payments do not include payments that are variable, dependent on specified factors or events.

Contract assets arise from unbilled amounts in customer arrangements when revenue recognized exceeds the amount billed to the customer and the Company’s right to payment is not just subject to the passage of time. The Company had no contract assets as of December 28, 2019 and December 29, 2018.

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

The Company generally satisfies performance obligations within one year of the contract inception date. As of December 28, 2019 and December 29, 2018, the Company’s wholly- or partially-unsatisfied performance obligations totaled $0.7 million and $1.5 million, respectively.

Disaggregated Revenue

In determining total net revenue under the revenue recognition guidance applicable to both periods presented, the Company reduces revenue by the amount of certain payments made to customers (see “Payments Made to Customers” above). The reconciliation of gross revenue to net revenue for these certain payments is shown below (in thousands):

	December 28, 2019		December 29, 2018
Gross revenue from sales to customers	$	25,844	$	14,657
Less: Clinical trial payments reducing revenue		2,240		1,640
Total net revenue	$	23,604	$	13,017

The Company disaggregates revenue from contracts with customers by product 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):

	December 28, 2019		December 29, 2018
Net revenue by OCS product:
OCS Lung net revenue	$	8,664	$	5,078
OCS Heart net revenue		11,442		5,956
OCS Liver net revenue		3,498		1,983
Total net revenue	$	23,604	$	13,017

	December 28, 2019		December 29, 2018
Net revenue by geography:
United States	$	16,253	$	6,543
Outside the U.S.		7,351		6,474
Total net revenue	$	23,604	$	13,017

Practical Expedients Used in Application of ASC 606

The Company has elected to apply the practical expedient for immaterial goods and services in the context of the contract. Accordingly, the Company does not assess whether promised goods or services are performance obligations if they are deemed immaterial in the context of the contract with the customer.

The Company has elected to apply the practical expedient for shipping. Accordingly, the Company does not consider shipping to be a contract performance obligation.

When applicable, the Company has elected to apply the practical expedient for considering the existence of a significant financing component. Accordingly, the Company does not adjust the promised amount of arrangement consideration for the effects of a significant financing component if it expects, at contract inception, that the period of time between the Company’s transfer of a promised good or service to a customer and the customer’s payment for that good or service will be one year or less.

Distributors

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

In its business with distributors, the Company enters into a distributor agreement under which the distributor places orders to the Company for its products in connection with the distributor’s own sales to identified end customers, and the Company confirms the identification of the end customer prior to accepting each order. The Company’s distributors do not stock OCS Consoles purchased from the Company and stock only minimal quantities of OCS disposable sets. Under these contractual arrangements, the Company invoices the distributor for the selling price (which reflects a distributor discount relative to typical end customer pricing) and payment to the Company from the distributor is not contingent upon the distributor’s collection from the end customer. The Company records revenue based on the amount of the discounted selling price.

When a sale to a distributor includes an OCS Console, the Company performs the training and OCS Console equipment set-up for the end customer. The Company recognizes no revenue from a distributor order that includes an OCS Console until the OCS Console has arrived at the customer site and the training and equipment set-up have been completed by the Company.

Research, Development and Clinical Trials Costs

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

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

Patent Costs

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

Foreign Currency Translation

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

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. 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 for each of the fiscal years ended December 28, 2019 and December 29, 2018.

Stock-Based Compensation

The Company measures stock-based option awards granted to employees, non-employees and directors based on their fair value on the date of grant using the Black-Scholes option-pricing model. Compensation expense for those awards is recognized over the requisite service period, which is generally the vesting period of the respective award. Generally, the Company issues awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company accounts for forfeitures as they occur and records compensation cost assuming all option holders will complete the requisite service period. If an award is forfeited, the Company reverses compensation expense previously recognized in the period the award is forfeited.

Prior to the adoption of Accounting Standards Update (“ASU”) 2018-07 on December 30, 2018 discussed below, the Company measured the fair value of stock-based option awards granted to non-employee consultants on the date that the related service was complete, which was generally the vesting date. Prior to the service completion date, compensation expense was recognized over the period during which services were rendered by such non-employee consultants. At the end of each financial reporting period prior to completion of the service, the fair value of these awards was remeasured using the then-current fair value of the Company’s common stock and updated assumption inputs in the Black-Scholes option-pricing model.

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

Comprehensive Loss and Accumulated Other Comprehensive Loss

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

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

Net Income (Loss) per Share

Prior to closing of the IPO, the Company followed the two-class method when computing net income (loss) per share, as TransMedics had issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed.

Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting net income (loss) attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents.

The outstanding convertible preferred stock contractually entitled the holders of such shares to participate in dividends but did not contractually require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

Subsequent to the closing of its IPO, the Company only has one class of shares outstanding and 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. For periods in which the Company reports a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders for each of the fiscal years ended December 28, 2019 and December 29, 2018.

Income Taxes

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

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

Recently Adopted Accounting Pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASC 606”). ASC 606 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry specific guidance. The new standards require entities to apportion consideration from contracts to performance obligations on a relative standalone selling price basis, based on a five-step model. Under ASC 606, revenue is recognized when a customer obtains control of a promised good or service and is recognized in an amount that reflects the consideration that the entity expects to receive in exchange for the good or service. In addition, ASC 606 provides guidance on accounting for certain revenue related costs, including costs associated with obtaining and fulfilling a contract. The Company adopted ASC 606 on December 30, 2018, applied using the modified retrospective method. Under this method, (i) the new guidance is applied to customer contracts that are not yet completed as of December 29, 2018, with the cumulative effect of initially applying the new guidance recorded as an adjustment to accumulated deficit on the effective date of adoption, and (ii) the Company’s historical results for all periods prior to December 30, 2018 are not adjusted. The Company did not elect to apply any permitted practical expedients as part of its adoption.

The Company’s adoption of ASC 606 did not substantially change the revenue recognition of its OCS products as applied under the prior revenue guidance, ASC 605, and, as a result, the adoption did not have a material impact on the Company’s consolidated financial statements. Accordingly, transitional disclosures were not presented. The Company’s revenue accounting policies related to ASC 605, which were applied in its reported amounts presented for all periods prior to December 30, 2018, were unchanged.

In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting (“ASU 2018-07”). ASU 2018-07 is intended to simplify aspects of share-based compensation issued to non-employees by making the guidance consistent with the accounting for employee share-based compensation. For public entities, ASU 2018-07 was required to be adopted for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. For nonpublic entities, ASU 2018-07 is effective for annual periods beginning after December 15, 2019. Early adoption is permitted for all entities but no earlier than the Company’s adoption of ASU 2014-09. The Company early-adopted ASU 2018-07 on December 30, 2018 and the adoption did not have a material impact on the Company’s financial statements.

Recently Issued Accounting Pronouncements

The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which sets out the principles for the recognition, measurement, presentation, and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less may be accounted for similar to existing guidance for operating leases today. For public entities, the guidance has been effective for annual reporting periods beginning after December 15, 2018 and for interim periods within those fiscal years. ASU 2016-02 initially required adoption using a modified retrospective approach, under which all years presented in the financial statements would be prepared under the revised guidance. In July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842), which added an optional transition method under which financial statements may be prepared under the revised guidance for the year of adoption, but not for prior years. Under the latter method, entities will recognize a cumulative catch-up adjustment to the opening balance of retained earnings in the period of adoption. In November 2019, the FASB issued ASU No. ASU 2019-10, which deferred the effective date for nonpublic entities to annual reporting periods beginning after December 15, 2020, and interim periods within fiscal years beginning after December 15, 2021. The Company is planning to adopt ASU 2016-02 in its fiscal year 2021, which begins on December 29, 2020, in accordance with the nonpublic company requirements. The Company is currently evaluating the method of adoption of this guidance and the impact that the adoption of ASU 2016-02 will have on its consolidated financial statements.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326). The new standard adjusts the accounting for assets held at amortized costs basis, including marketable securities accounted for as available for sale, and trade receivables. The standard eliminates the probable initial recognition threshold and requires an entity to reflect its current estimate of all expected credit losses. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial assets to present the net amount expected to be collected. For public entities except smaller reporting companies, the guidance is effective for annual reporting periods beginning after December 15, 2019 and for interim periods within those fiscal years. For non-public entities and smaller reporting companies, the guidance was effective for annual reporting periods beginning after December 15, 2021. Early adoption is permitted for all entities. In November 2019, the FASB issued ASU No. 2019-10, which deferred the effective date for non-public entities to annual reporting periods beginning after December 15, 2022, including interim periods within those fiscal years. Early application continues to be allowed. The Company is currently assessing the impact of the adoption of this guidance on its financial statements.

Marketable Securities and Fair Value Measurements

12 Months Ended

Dec. 28, 2019

Marketable Securities And Fair Value Measurements [Abstract]

Marketable Securities and Fair Value Measurements

3.	Marketable Securities and Fair Value Measurements

Marketable securities by security type consisted of the following (in thousands):

	December 28, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities (due within one year)	$	23,318	$	17	$	—		$	23,335
U.S. government agency bonds (due within one year)		37,224		39		(2	)	$	37,261
	$	60,542	$	56	$	(2	)	$	60,596

The Company had no marketable securities as of December 29, 2018.

The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis (in thousands):

	Fair Value Measurements at December 28, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	11,760	$	—	$	—	$	11,760
Marketable securities:
U.S. Treasury securities		—		23,335		—		23,335
U.S. government agency bonds		—		37,261		—		37,261
	$	11,760	$	60,596	$	—	$	72,356

	Fair Value Measurements at December 29, 2018 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	13,586	$	—	$	—	$	13,586
	$	13,586	$	—	$	—	$	13,586
Liabilities:
Preferred stock warrant liability	$	—	$	—	$	898	$	898

Money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. U.S. Treasury securities and U.S. government agency bonds were valued by the Company using quoted prices in active markets for similar securities, which represent a Level 2 measurement within the fair value hierarchy. There were no transfers between Level 1, Level 2 and Level 3 during the fiscal years ended December 28, 2019, and December 29, 2018.

The preferred stock warrant liability in the table above consisted of the fair value of warrants to purchase Series D and Series F convertible preferred stock (see Note 9) and was based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The Company’s valuation of the preferred stock warrants utilized the Black-Scholes option-pricing model, which incorporated assumptions and estimates to value the preferred stock warrants. The Company assesses these assumptions and estimates on a quarterly basis as additional information impacting the assumptions was obtained. Changes in the fair value of the preferred stock warrants were recognized as other income (expense) in the consolidated statements of operations. On May 6, 2019, immediately prior to the closing of the IPO, the warrants to purchase preferred stock were converted into warrants to purchase common stock, and the fair value of the warrant liability at that time was reclassified to common stock. As a result, subsequent to the closing of the IPO, the Company no longer remeasures the fair value of the warrant liability at each reporting date.

The quantitative elements associated with the Company’s Level 3 inputs impacting the fair value measurement of the preferred stock warrant liability included the fair value per share of the underlying Series D and Series F convertible preferred stock, the remaining contractual term of the warrants, risk-free interest rate, expected dividend yield and expected volatility of the price of the underlying preferred stock. The most significant assumption in the Black-Scholes option-pricing model impacting the fair value of the preferred stock warrants was the fair value of the Company’s convertible preferred stock as of each remeasurement date. The Company determined the fair value per share of the underlying preferred stock by taking into consideration the most recent sales of its convertible preferred stock, results obtained from third-party valuations and additional factors that the Company deemed relevant. As of December 29, 2018, the fair value of each share of Series D and Series F convertible preferred stock was $6.21 per share and $5.73 per share, respectively. The Company historically was a private company and lacked company-specific historical and implied volatility information of its stock. Therefore, it estimated its expected stock volatility based on the historical volatility of publicly traded peer companies for a term equal to the remaining contractual term of the warrants. The risk-free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company had estimated a 0% dividend yield based on the expected dividend yield and the fact that the Company had never paid or declared dividends.

Based on the terms and conditions of the warrants and pursuant to the Corporate Reorganization, immediately prior to the closing of the Company’s IPO on May 6, 2019, the preferred stock warrants converted to common stock warrants. On that date, the Company remeasured the warrants and reclassified the total carrying value to stockholders’ equity (deficit). The Company performed the final measurement of the warrants using the fair value of the underlying common shares of $27.41 per share on May 6, 2019 and recorded the change in fair value in other income (expense), net in the consolidated statements of operations.

The following table provides a roll-forward of the aggregate fair values of the Company’s preferred stock warrants for which fair value is determined by Level 3 inputs (in thousands):

	Preferred Stock Warrant Liability
Fair value at December 30, 2017	$	353
Change in fair value		545
Fair value at December 29, 2018	$	898
Change in fair value		341
Reclassification of warrant liability to equity upon initial public offering		(1,239	)
Fair value at December 28, 2019	$	—

Inventory

12 Months Ended

Dec. 28, 2019

Inventory Disclosure [Abstract]

Inventory

Inventory consisted of the following (in thousands):

	December 28, 2019		December 29, 2018
Raw materials	$	4,881	$	3,817
Work-in-process		903		882
Finished goods		5,432		4,578
	$	11,216	$	9,277

During the fiscal years ended December 28, 2019 and December 29, 2018, the Company made non-cash transfers of OCS Consoles from inventory to property and equipment (OCS Consoles loaned to customers) of $2.1 million and $1.4 million, respectively.

Property and Equipment, Net

12 Months Ended

Dec. 28, 2019

Property Plant And Equipment [Abstract]

Property and Equipment, Net

5.	Property and Equipment, Net

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

	December 28, 2019			December 29, 2018
Manufacturing equipment	$	1,408		$	1,235
OCS Consoles loaned to customers		6,005			3,898
Computer equipment and software		1,273			1,087
Laboratory equipment		524			512
Office and trade show equipment		177			173
Leasehold improvements		1,319			1,319
Construction-in-progress		433			387
	$	11,139		$	8,611
Less: Accumulated depreciation and amortization		(6,347	)		(5,137	)
	$	4,792		$	3,474

During the fiscal years ended December 28, 2019 and December 29, 2018, total depreciation and amortization expense was $1.2 million and $0.8 million, respectively. Of those amounts, $1.0 million and $0.6 million, respectively, was recorded as expense in cost of revenue related to the depreciation of OCS Consoles loaned to customers. The Company retains title to OCS Consoles loaned to customers.

Construction-in-progress recorded as of December 28, 2019 and December 29, 2018 was primarily related to the in-process construction of manufacturing equipment.

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 28, 2019

Accrued Expenses And Other Current Liabilities [Abstract]

Accrued Expenses and Other Current Liabilities

6.	Accrued Expenses and Other Current Liabilities

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

	December 28, 2019		December 29, 2018
Accrued research, development and clinical trials expenses	$	3,144	$	1,853
Accrued payroll and related expenses		3,604		1,729
Accrued financing fees (Note 13)		120		1,466
Accrued professional fees		537		549
Accrued premium for manufacturing contract (Note 13)		—		1,089
Accrued other		927		492
	$	8,332	$	7,178

Long-Term Debt

12 Months Ended

Dec. 28, 2019

Debt Disclosure [Abstract]

Long-Term Debt

7.	Long-Term Debt

As of December 28, 2019 and December 29, 2018, long-term debt consisted of the following (in thousands):

	December 28, 2019			December 29, 2018
Principal amount of long-term debt	$	35,000		$	35,000
Less: Current portion of long-term debt		—			—
Long-term debt, net of current portion		35,000			35,000
Debt discount, net of accretion		(1,139	)		(1,424	)
Accrued end-of-term payments		285			94
Long-term debt, net of discount and current portion	$	34,146		$	33,670

Hercules Loan and Security Agreement

The Company had a loan agreement, entered into in 2015, and amended in 2016 (collectively, the “Amended Loan Agreement”) with Hercules Technology Growth Capital, Inc. (“Hercules”). The Amended Loan Agreement provided for borrowings of $8.5 million under a term loan, all of which was borrowed by the Company prior to 2016. Borrowings under the Amended Loan Agreement bore interest at an annual rate equal to the greater of (i) 9.55% plus The Wall Street Journal prime rate minus 4.25% or (ii) 9.55%. Borrowings under the Amended Loan Agreement were repayable in monthly interest-only payments through December 2017 and in equal monthly payments of principal and accrued interest from January 2018 until the maturity date in February 2020. The Company was also required to make an end-of-term payment of $0.5 million upon the earlier of the payment of all obligations under the Amended Loan Agreement or the maturity date in February 2020.

In connection with entering into the Amended Loan Agreement, Hercules received a warrant to purchase 34,068 shares of Series F convertible preferred stock, at an exercise price of $4.99 per share, exercisable immediately. The fair value of the warrant on the issuance date of $0.1 million was recorded as a debt discount and as a component of the preferred stock warrant liability. On May 6, 2019, immediately prior to the closing of our IPO, the warrants to purchase preferred stock were converted into warrants to purchase common stock. The warrants for common stock will expire in May 2024.

In June 2018, the Company repaid all amounts due under the Amended Loan Agreement, including $6.7 million of principal repayments, and the Amended Loan Agreement was terminated. Upon prepayment of the outstanding amounts, the Company recorded a loss on extinguishment of debt of $0.3 million, which was classified as other expense in the consolidated statements of operations.

OrbiMed Credit Agreement

In June 2018, the Company entered into a credit agreement (the “Credit Agreement”) with OrbiMed Royalty Opportunities II, LP (“OrbiMed”) pursuant to which OrbiMed made certain term loans available to the Company. The Credit Agreement provides for aggregate maximum borrowings of up to $65.0 million, consisting of (i) $35.0 million upon entering into the Credit Agreement, which was borrowed by the Company in June 2018, and (ii) potential additional borrowings of up to $30.0 million that could have become available upon the Company’s achievement of specified revenue thresholds and a regulatory milestone by determinable dates. The Company did not achieve these revenue thresholds and regulatory milestones by such dates, and therefore OrbiMed’s commitment to fund any additional borrowing was terminated.

Borrowings under the Credit Agreement bear interest at an annual rate equal to the London Interbank Offered Rate (“LIBOR”), subject to a minimum of 1.0% and a maximum of 4.0%, plus 8.5% (the “Applicable Margin”), subject in the aggregate to a maximum interest rate of 11.5%. In addition, borrowings under the Credit Agreement bear paid-in-kind (“PIK”) interest at an annual rate equal to the amount by which LIBOR plus the Applicable Margin exceeds 11.5%, but not to exceed 12.5%. The PIK interest is added to the principal amount of the borrowings outstanding at the end of each quarter until the maturity date of the Credit Agreement in June 2023. Borrowings under the Credit Agreement are repayable in quarterly interest-only payments until the maturity date, at which time all principal and accrued interest is due and payable. At its option, the Company may prepay outstanding borrowings under the Credit Agreement, subject to a prepayment premium of 9.0% of the principal amount of any prepayment within the first three years, which percentage decreases annually until it reaches zero at the end of three years. The Company is also required to make a final payment in an amount equal to 3.0% of the principal amount of any prepayment or repayment. The final payment is being accreted to interest expense over the term of the Credit Agreement using the effective interest method.

In connection with entering into the Credit Agreement, the Company paid OrbiMed an upfront fee of $0.9 million and paid other costs to OrbiMed and third parties of $0.7 million, both of which were recorded by the Company as a debt discount. The debt discount is reflected as a reduction of the carrying value of long-term debt on the Company’s consolidated balance sheet and is being accreted to interest expense over the term of the Credit Agreement using the effective interest method.

All obligations under the 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, including a perfected security interest in substantially all tangible and intangible assets of the Company and each guarantor. Under the Credit Agreement, the Company has agreed to certain affirmative and negative covenants to which it will remain subject until maturity. The covenants include maintaining a minimum liquidity amount of $3.0 million; the requirement, on an annual basis, to deliver to OrbiMed annual audited financial statements with an unqualified audit opinion from the Company’s independent registered public accounting firm; and restrictions on the Company’s activities, including limitations on dispositions, mergers or acquisitions; encumbering its intellectual property; incurring indebtedness or liens; paying dividends; making certain investments; and engaging in certain other business transactions. As of December 28, 2019, the Company was in compliance with all covenants of the Credit Agreement.

The obligations under the 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, including the minimum liquidity and unqualified audit opinion covenants, and a material adverse change in the Company’s business, operations or other financial condition.

Upon the occurrence of an event of default and until such event of default is no longer continuing, the Applicable Margin will increase by 4.0% per annum. If an event of default (other than certain events of bankruptcy or insolvency) occurs and is continuing, OrbiMed may declare all or any portion of the outstanding principal amount of the borrowings plus accrued and unpaid interest to be due and payable. Upon the occurrence of certain events of bankruptcy or insolvency, all of the outstanding principal amount of the borrowings plus accrued and unpaid interest will automatically become due and payable. In addition, the Company may be required to prepay outstanding borrowings, subject to certain exceptions, with portions of net cash proceeds of certain asset sales and certain casualty and condemnation events.

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

As of December 28, 2019, the interest rate applicable to borrowings under the Credit Agreement was 10.63%. During the fiscal year ended December 28, 2019, the weighted average effective interest rate on outstanding borrowings under the Credit Agreement was approximately 12.36%.

Convertible Preferred Stock

12 Months Ended

Dec. 28, 2019

Convertible Preferred Stock [Abstract]

Convertible Preferred Stock

8.	Convertible Preferred Stock

TransMedics, Inc. issued Series A-1 convertible preferred stock (the “Series A-1 Preferred Stock”), Series B convertible preferred stock (the “Series B Preferred Stock”), Series B-1 convertible preferred stock (the “Series B-1 Preferred Stock”), Series C convertible preferred stock (the “Series C Preferred Stock”), Series D convertible preferred stock (the “Series D Preferred Stock”), Series E convertible preferred stock (the “Series E Preferred Stock”) and Series F convertible preferred stock (the “Series F Preferred Stock”). The Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock, Series D Preferred Stock, Series E Preferred Stock and Series F Preferred Stock are collectively referred to as the “Preferred Stock”. The Series A-1 Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock and Series C Preferred Stock were collectively referred to as the “Junior Preferred Stock”, a subset of the Preferred Stock.

Upon issuance of each class of Preferred Stock, the Company assessed the embedded conversion and liquidation features of the securities and determined that such features did not require the Company to separately account for these features. The Company also concluded that no beneficial conversion feature existed on the issuance date of each class of Preferred Stock.

As of December 29, 2018, Preferred Stock consisted of the following (in thousands, except share amounts):

	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Preference		Common Stock Issuable Upon Conversion
Series A-1 Preferred Stock		13,332		13,332	$	3,333	$	33		984
Series B Preferred Stock		3,771,020		3,624,650		10,691		12,382		286,102
Series B-1 Preferred Stock		2,560,245		2,560,245		8,746		8,746		202,086
Series C Preferred Stock		6,198,057		6,198,057		14,970		15,495		1,770,873
Series D Preferred Stock		14,740,000		14,565,000		34,868		72,825		4,161,428
Series E Preferred Stock		6,562,232		6,562,232		29,865		29,966		1,874,923
Series F Preferred Stock		16,931,168		16,880,624		84,046		84,234		4,823,028
		50,776,054		50,404,140	$	186,519	$	223,681		13,119,424

Immediately prior to the closing of the IPO on May 6, 2019, pursuant to the Corporate Reorganization, all of the outstanding shares of convertible preferred stock of TransMedics were converted into an aggregate of 13,119,424 shares of common stock of TransMedics Group.

Warrants to Purchase Preferred Stock

12 Months Ended

Dec. 28, 2019

Warrants And Rights Note Disclosure [Abstract]

Warrants to Purchase Preferred Stock

9.	Warrants to Purchase Preferred Stock

In connection with prior debt agreements and amendments to such agreements, TransMedics had outstanding warrants to purchase shares of Series D Preferred Stock and Series F Preferred Stock as of December 29, 2018. The Company classified all of its preferred stock warrants as a liability on its consolidated balance sheets because the warrants were freestanding financial instruments that could require TransMedics to transfer assets upon exercise. The liability associated with each of these warrants was initially recorded at fair value upon the issuance date of each warrant and subsequently remeasured to fair value at each reporting date. The fair value of these warrants was determined using the Black-Scholes option-pricing model (see Note 3), and the resulting change in fair value of the warrant liability was recorded in other income (expense) in the Company’s consolidated statements of operations (see Note 3).

Immediately prior to the closing of the IPO on May 6, 2019, pursuant to the Corporate Reorganization, all of the outstanding preferred stock warrants of TransMedics were converted into warrants to purchase an aggregate of 64,440 shares of which warrants to purchase 50,000 shares of common stock at an exercise price of $8.75 per share expire on November 7, 2022 and warrants to purchase 14,440 shares of common stock at an exercise price of $17.47 per share have an expiration date of May 6, 2024. Upon conversion, the fair value of the warrant liability at that time was reclassified to common stock. As a result, subsequent to the closing of the Company’s IPO, the Company will no longer remeasure the fair value of the warrant liability at each reporting date.

Equity

12 Months Ended

Dec. 28, 2019

Equity [Abstract]

Equity

10.

Equity

On May 6, 2019, the Company filed a restated certificate of incorporation in the State of Massachusetts, which, among other things, restated the number of shares of all classes of stock that the Company has authority to issue to 175,000,000 shares, consisting of (i) 25,000,000 shares of preferred stock, no par value per share, and (ii) 150,000,000 shares of common stock, no par value per share. The preferred stock will have such rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, as shall be determined by the Company’s boards of directors upon issuance. The shares of preferred stock currently undesignated. Each share of common stock is entitled to one vote on all matters submitted to a vote of the Company’s stockholders. The holders of common stock, voting exclusively and as a separate class, are entitled to elect two directors of the Company. The holders of common stock are entitled to receive dividends, if any, as may be declared by the board of directors, as described above. Through December 28, 2019, no dividends had been declared or paid.

Stock-Based Compensation

12 Months Ended

Dec. 28, 2019

Stockholders Equity Note [Abstract]

Stock-Based Compensation

11.	Stock-Based Compensation

2014 and 2019 Stock Incentive Plan

The Company’s 2014 Stock Incentive Plan (the “2014 Plan”) permitted the Company to sell or issue incentive stock options or nonqualified stock options, stock appreciation rights, restricted stock, restricted stock units, and other stock-based awards to employees, directors, and non-employee consultants of the Company. The 2014 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting, and other restrictions were determined at the discretion of the board of directors, or its committee if so delegated.

Stock options granted under the 2014 Plan with service-based vesting conditions typically vest over three or four years and expire after ten years. Following the effectiveness of the Company’s 2019 Stock Incentive Plan (the “2019 Stock Plan”) in April 2019, no future awards will be made under the 2014 Plan. Additionally, shares underlying awards under the 2014 Plan that expire or are terminated, surrendered, or canceled without the delivery of shares will be available for future awards under the 2019 Stock Plan.

2019 Stock Incentive Plan and Options Grants:

On April 15, 2019, TransMedics Group’s board of directors adopted and its sole stockholder approved the 2019 Stock Plan, which became effective on that same date. The 2019 Stock 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 Stock Plan was 3,428,571 shares, plus the number of shares underlying awards under 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 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 Stock Plan. In addition, the number of shares available for issuance under the 2019 Stock Plan (i) will not be increased by any shares delivered under the 2019 Stock 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 Stock Plan. As of December 28, 2019, 2,981,866 shares of common stock were available for issuance under the 2019 Plan.

During the fiscal year ended December 28, 2019, the Company granted options to its employees and a director with service-based vesting for the purchase of an aggregate of 463,357 shares of common stock with a weighted average grant fair value of $8.55 per share.

2019 Employee Stock Purchase Plan

On April 15, 2019, TransMedics Group’s board of directors adopted and its sole stockholder approved the 2019 Employee Stock Purchase Plan (the “2019 ESPP”), which became effective that same date. A total of 371,142 shares of common stock of TransMedics Group are reserved for issuance under the 2019 ESPP as of December 28, 2019. As of December 28, 2019, no shares have been issued under the 2019 ESPP and 371,142 shares remained available for issuance.

Stock Option Valuation

The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company historically has been a private company and lacks company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

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

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Risk-free interest rate	2.29%				2.91	%
Expected term (in years)		6.02			6.06
Expected volatility	52%				51	%
Expected dividend yield		0	%		0	%

The following table summarizes the Company’s option activity since December 29, 2018:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 29, 2018		1,625,758		$	1.76		5.8	$	20,726
Granted		463,357			16.68
Exercised		(124,226	)		1.60
Forfeited		(12,589	)		3.23
Outstanding as of December 28, 2019		1,952,300		$	5.31		5.87	$	26,415
Vested and expected to vest as of December 28, 2019		1,952,300		$	5.31		5.87	$	26,415
Options exercisable as of December 28, 2019		1,285,242		$	1.91		4.34	$	21,735

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the fiscal years ended December 28, 2019 and December 29, 2018 was $2.3 million and less than $0.2 million, respectively.

The weighted average grant-date fair value of stock options granted during the fiscal years ended December 28, 2019 and December 29, 2018 was $8.55 per share and $0.88 per share, respectively.

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

Stock-Based Compensation

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

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Cost of revenue	$	17	$	7
Research, development and clinical trials expenses		104		42
Selling, general and administrative expenses		733		95
	$	854	$	144

As of December 28, 2019, total unrecognized compensation cost related to unvested employee and director stock-based awards was $3.8 million, which is expected to be recognized over a weighted average period of 2.75 years.

Income Taxes

12 Months Ended

Dec. 28, 2019

Income Tax Disclosure [Abstract]

Income Taxes

12.	Income Taxes

2017 U.S. Tax Reform

On December 22, 2017, the TCJA was signed into United States law. The TCJA includes a number of changes to existing tax law, including, among other things, a permanent reduction in the federal corporate income tax rate from a top marginal tax rate of 35% to a flat rate of 21%, effective as of January 1, 2018, as well as limitation of the deduction for net operating losses to 80% of annual taxable income and elimination of net operating loss carrybacks, in each case, for losses arising in taxable years beginning after December 31, 2017 (though any such net operating losses may be carried forward indefinitely). The TCJA also transitions international taxation from a worldwide system to a modified territorial system and includes base erosion prevention measures on non-U.S. earnings. These changes were effective January 1, 2018. The TCJA also includes a one-time mandatory deemed repatriation tax on accumulated foreign subsidiaries’ previously untaxed foreign earnings, referred to as the Transition Toll Tax.

In connection with the initial analysis of the impact of the TCJA, the Company remeasured its deferred tax assets based on the rates at which they are expected to reverse in the future, which is generally 21% for federal tax purposes. The remeasurement of the Company’s deferred tax assets was offset by a change in the valuation allowance. As a result, no income tax expense or benefit was recognized as of the enactment date of the TCJA.

The FASB issued ASU 2018-05 to address the application of GAAP in situations when a registrant does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the TCJA. As permitted by ASU 2018-05, the Company recorded provisional estimates of the impact of the TCJA as of December 22, 2017 and for the fiscal year ended December 30, 2017. In December 2018, the Company finalized its accounting analysis of the impact of the TCJA based on the guidance, interpretations and data available during the fiscal year ended December 29, 2018. As a result of finalizing the accounting analysis, the Company did not record any adjustments to the provisional amounts recorded in 2017.

Income Taxes

During the fiscal years ended December 28, 2019 and December 29, 2018, the Company recorded no income tax benefits for the net operating losses incurred or for the research and development tax credits generated in each year in the United States, due to its uncertainty of realizing a benefit from those items. The Company generated income in the Netherlands for the fiscal years ended December 28, 2019 and December 29, 2018 and, accordingly, recorded a foreign income tax provision of less than $0.1 million for each of the fiscal years ended December 28, 2019 and December 29, 2018.

Income (loss) before income taxes consisted of the following (in thousands):

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
United States	$	(33,668	)	$	(23,919	)
Foreign		161			204
	$	(33,507	)	$	(23,715	)

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

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Federal statutory income tax rate		(21.0	)%		(21.0	)%
State taxes, net of federal benefit		(6.2	)%		(5.8	)%
Federal and state research and development tax credits		(2.8	)%		(3.0	)%
Nondeductible items		0.2	%		1.4	%
Other		0.9	%		0.5	%
Change in deferred tax asset valuation allowance		29.0	%		28.1	%
Effective income tax rate		0.1	%		0.2	%

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

	December 28, 2019			December 29, 2018
Deferred tax assets:
Net operating loss carryforwards	$	74,206		$	63,041
Capitalized research and development expense		8,505			10,863
Research and development tax credit carryforwards		10,745			9,818
Accrued expenses		1,309			1,161
Stock-based compensation expense		243			260
Deferred rent		157			227
Total deferred tax assets		95,165			85,370
Deferred tax liabilities:
Other		(141	)		(54	)
Total deferred tax liabilities		(141	)		(54	)
Valuation allowance		(95,024	)		(85,316	)
Net deferred tax assets	$	—		$	—

As of December 28, 2019, the Company had U.S. federal and state net operating loss carryforwards of $287.8 million and $217.8 million, respectively, which may be available to offset future taxable income and begin to expire in 2020 and 2030, respectively. The Company’s federal net operating losses include $72.8 million, which can be carried forward indefinitely. As of December 28, 2019, the Company also had U.S. federal and state research and development tax credit carryforwards of $7.0 million and $4.7 million, respectively, which may be available to offset future tax liabilities and begin to expire in 2020 and 2024, respectively. As of December 28, 2019, the Company had no foreign net operating loss carryforwards.

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

As required by Accounting Standard Codification 740, management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards. Management has determined that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets and, as a result, has a valuation allowance of approximately $95.0 million has been recorded.

The Company had no unrecognized tax benefits or related interest and penalties accrued for the fiscal years ended December 28, 2019 and December 29, 2018. The Company's policy is to record any interest or penalties related to income taxes as part of the income tax provision.

The Company files income tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending federal or state tax examinations. The Company has open tax years subject to examination from FY 2016 to present; however, carryforward attributes that were generated prior to December 28, 2014 may still be adjusted upon examination by federal, state, or local tax authorities if they either have been or will be used in a future period.

Changes in the valuation allowance for deferred tax assets during the fiscal years ended December 28, 2019 and December 29, 2018 related primarily to the increase in net operating loss carryforwards and research and development tax credit carryforwards in 2019 and 2018 partially offset in 2018 by a decrease in deferred tax assets resulting from the decreased federal corporate tax rate impact of the TCJA, and were as follows (in thousands):

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Valuation allowance as of beginning of year	$	(85,316	)	$	(78,650	)
Decreases recorded as benefit to income tax provision		—			—
Increases recorded to income tax provision		(9,708	)		(6,666	)
Valuation allowance as of end of year	$	(95,024	)	$	(85,316	)

As of December 28, 2019 and December 29, 2018, the Company had not recorded any amounts for unrecognized tax benefits. The Company’s policy is to record interest and penalties related to income taxes as part of its income tax provision. As of December 28, 2019 and December 29, 2018, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts had been recognized in the Company’s consolidated statements of operations. The Company files income tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending tax examinations. The Company is open to future tax examination under statute from 2016 to the present; however, carryforward attributes that were generated prior to December 28, 2014 may still be adjusted upon examination by federal, state or local tax authorities if they either have been or will be used in a future period.

Commitments and Contingencies

12 Months Ended

Dec. 28, 2019

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

13.	Commitments and Contingencies

Operating Leases

The Company leases its office, laboratory and manufacturing space under two noncancelable operating leases that expire in December 2021. The lease agreements include payment escalations, rent holidays and other lease incentives, which are accrued or deferred as appropriate such that rent expense for each lease is recognized on a straight-line basis over the respective lease terms, recording deferred rent for rent expense incurred but not yet paid (see Note 2). Rent expense for the fiscal years ended December 28, 2019 and December 29, 2018 was $1.2 million and $1.2 million, respectively.

Future minimum lease payments under operating leases as of December 28, 2019 are as follows (in thousands):

Fiscal Year Ending:
December 26, 2020	$	1,570
December 25, 2021		1,589
	$	3,159

License Agreement with the Department of Veterans Affairs

In 2002, the Company entered into a license agreement with the Department of Veterans Affairs (the “VA”), under which the Company was granted an exclusive, worldwide license under specified patents to make, use, sell and import certain technology used in the Company’s products and a non-exclusive, worldwide license to make, use, sell and import solutions for use in or with those products. The rights under the license agreement continue until the expiration of the last to expire of the licensed patents. The majority of the licensed U.S. patents expired in 2017, and the foreign patents expired in September 2018. However, the Company has requested a patent term extension for one U.S. patent covered by the VA license agreement, U.S. Patent No. 6100082. The Company has been granted an interim patent term extension for this patent. As of March 17, 2020, the issuance date of the consolidated financial statements as of December 28, 2019 and for the fiscal year then ended, the Company had not received final approval of the patent extension beyond the interim patent term extension already granted. The maximum extension granted would be through May 2022; however, the length of the patent term extension will be determined by the United States Patent and Trademark Office. The license includes the right to grant sublicenses, subject to approval by the VA and other restrictions, and is subject to the U.S. government’s right to practice the licensed patents on its own behalf without payment of a royalty and obligation to grant certain sublicenses as necessary to fulfill public health, welfare and safety needs. The license agreement also requires the Company to make its products covered by the licensed patents available to the public on reasonable terms and to provide the U.S. government such products at the lowest price.

As consideration for the licenses granted by the VA, the Company is obligated to pay tiered royalties ranging from a low single-digit to a mid single-digit percentage on net sales of each product covered by a licensed patent (subject to a minimum aggregate royalty payment of less than $0.1 million per year during each of the first five years after the first commercial sale, after which no minimum is required). Royalties will be paid by the Company on a licensed product-by-licensed product and country-by-country basis, beginning on the first commercial sale of such licensed product in such country until expiration of the last valid patent claim covering such licensed product in such country. The Company is also responsible for all costs related to the amendment, prosecution and maintenance of the licensed patent rights.

The Company paid the VA royalties of $0.3 million and $0.2 million during the fiscal years ended December 28, 2019 and December 29, 2018, respectively. The Company also accrued VA royalties of $0.1 million as of December 28, 2019.

The VA license agreement can be terminated by the Company or the VA only if the other party fails to cure its material breach within a specified period after receiving notice of such breach.

Accrued Financing Fee

As of December 29, 2018, the Company was obligated to pay financing fees of $1.5 million to former financial advisors related to issuances of Series B preferred stock and Series D preferred stock in periods prior to 2016. These financing fees were contingently payable in cash only upon an initial public offering or certain alternative transactions, including a sale of the company. As a result of the IPO in May 2019, the Company became obligated to pay these previously accrued financing fees. The Company settled the obligations in full during the third and fourth quarter of the fiscal year ended December 28, 2019.

401(k) Savings Plan

The Company has a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code. This plan covers substantially all employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Company contributions to the plan may be made at the discretion of the board of directors. As of December 28, 2019 and December 29, 2018, the Company had not made any contributions to the plan.

Indemnification Agreements

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

The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not currently aware of any indemnification claims and had not accrued any liabilities related to such obligations in its consolidated financial statements as of December 28, 2019 or December 29, 2018.

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 expense as incurred the costs related to such legal proceedings.

Net Loss per Share

12 Months Ended

Dec. 28, 2019

Earnings Per Share [Abstract]

Net Loss per Share

14.	Net Loss per Share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts):

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Numerator:
Net loss attributable to common stockholders	$	(33,547	)	$	(23,756	)
Denominator:
Weighted average common shares outstanding, basic and diluted		14,204,787			1,358,694
Net loss per share attributable to common stockholders, basic and diluted	$	(2.36	)	$	(17.48	)

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

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Convertible preferred stock (as converted to common stock)		—		13,119,424
Warrants to purchase convertible preferred stock (as converted to common stock)		—		64,440
Warrants to purchase common stock		64,440		—
Options to purchase common stock		1,952,300		1,625,798
		2,016,740		14,809,662

Segment Reporting and Geographic Data

12 Months Ended

Dec. 28, 2019

Segment Reporting [Abstract]

Segment Reporting and Geographic Data

15.	Segment Reporting and Geographic Data

The Company has determined that it operates in one segment (see Note 2).

Net revenue by OCS product is summarized as follows (in thousands):

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Net revenue by OCS product:
OCS Lung net revenue	$	8,664	$	5,078
OCS Heart net revenue		11,442		5,956
OCS Liver net revenue		3,498		1,983
Total net revenue	$	23,604	$	13,017

Financial data by geographical area is summarized as follows (in thousands):

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Net revenue by country⁽¹⁾:
United States	$	16,253	$	6,543
United Kingdom		2,233		2,580
Germany		1,147		1,456
All other countries		3,971		2,438
Total net revenue	$	23,604	$	13,017

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Long-lived assets by country⁽²⁾:
United States	$	4,007	$	2,567
All other countries		785		907
Total long-lived assets	$	4,792	$	3,474

(1)	Net revenue by country is categorized based on the location of the end customer.

(2)	The Company’s only long-lived assets consist of property and equipment, net of depreciation, which are categorized based on their location of domicile.

Significant Customer Concentrations

12 Months Ended

Dec. 28, 2019

Risks And Uncertainties [Abstract]

Significant Customer Concentrations

16.	Significant Customer Concentrations

Significant customers are those that accounted for 10% or more of the Company’s net revenue or accounts receivable, as set forth in the following tables for the periods presented:

*	Less than 10%

	Accounts Receivable
	December 28, 2019	December 29, 2018
Company A	*		13	%
Company B	*		15	%

*	Less than 10%

Related Party Transactions

12 Months Ended

Dec. 28, 2019

Related Party Transactions

17.	Related Party Transactions

Employment of Dr. Amira Hassanein

Dr. Amira Hassanein, who serves as Product Director for the Company’s OCS Lung program, is the sister of Dr. Waleed Hassanein, the Company’s President, Chief Executive Officer and a member of the Company’s board of directors. The Company paid Dr. Amira Hassanein $0.2 million and $0.2 million in total compensation in the fiscal years ended December 28, 2019 and December 29, 2018, respectively, for her services as an employee.

Subsequent Events

12 Months Ended

Dec. 28, 2019

Subsequent Events [Abstract]

Subsequent Events

18.	Subsequent Events

On January 9, 2020, the Company entered into an Omnibus Amendment #1 to Lease with respect to its corporate headquarters. The Amendment, with terms effective retroactively to December 23, 2019, made certain changes to the Lease Agreements, dated June 25, 2004. Pursuant to the Omnibus Amendment #1, the Company amended the Leases to include an additional 39,744 square feet for general office use and an additional 11,735 square feet of operational use. The Company also extended the existing Lease term through December 31, 2026 with an option to extend the term of the Lease beyond the new expiration date for one additional period of five years. In addition, under the amended Agreement, the Landlord will contribute $3.4 million toward the Company’s work on the improvement of the premises.

This Amendment provides for annual base rent for the existing and expansion premises of approximately $1.9 million for the first year of the Lease. Thereafter, the annual base rent will increase at an average of 2.5% until the end of the term. The Company is also obligated to pay the Landlord certain costs, taxes, and operating expenses, subject to certain exclusions.

On February 27, 2020, the Company’s Board of Directors approved a change in the Company’s fiscal year end from the last Saturday in December to December 31. Following such change, the Company’s current fiscal year will end on December 31, 2020. Effective with this change, the Company’s quarterly results will be for the three-month periods ending March 31, June 30, September 30 and December 31.

Selected Quarterly Results of Operations Data (Unaudited)

12 Months Ended

Dec. 28, 2019

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Results of Operations Data (Unaudited)

19.	Selected Quarterly Results of Operations Data (Unaudited)

The following table sets forth the selected quarterly statements of operations data for each of the eight most recent fiscal quarters in the period ended December 28, 2019. The selected quarterly statements of operations data have been prepared on the same basis as the audited consolidated financial statements and include all adjustments necessary to present fairly, in all material respects, the information set forth therein on a consistent basis. The Company’s operating results may fluctuate due to a variety of factors. Because the timing of organ transplant procedures is generally unpredictable, the Company has not experienced seasonality in its business from quarter to quarter and does not expect to do so in the foreseeable future. The results of historical periods are not necessarily indicative of the results to be expected for a full year or any future period.

	Fiscal Three Months Ended
	Dec. 28, 2019			Sept. 28, 2019			June 29, 2019			Mar. 30, 2019			Dec. 29, 2018			Sept. 29, 2018			June 30, 2018			Mar. 31, 2018
Net revenue	$	6,057		$	7,205		$	5,666		$	4,676		$	3,544		$	4,039		$	2,915		$	2,519
Gross profit		3,741			4,216			3,333			2,573			1,499			2,132			1,179			924
Loss from operations		(8,694	)		(7,242	)		(7,705	)		(5,962	)		(6,361	)		(3,939	)		(5,156	)		(4,781	)
Net loss	$	(9,177	)		(8,280	)		(9,195	)		(6,895	)	$	(7,635	)	$	(5,105	)	$	(6,115	)	$	(4,901	)
Net loss per share (basic and diluted)	$	(0.43	)	$	(0.39	)	$	(0.70	)	$	(4.86	)	$	(5.48	)	$	(3.73	)	$	(4.57	)	$	(3.61	)

Revision

Subsequent to the filing of its Form 10-Q for the quarterly period ended June 29, 2019, the Company discovered an error in the calculation of basic and diluted net loss per share attributable to common stockholders for the three and six months ended June 30, 2018. The calculation of the weighted average number of common shares outstanding (basic and diluted) as originally reported had not appropriately reflected the 3.5-for-one conversion ratio applied to common stock in the Corporate Reorganization. The correction of this error decreased the weighted average number of common shares outstanding (basic and diluted) for the three and six months ended June 30, 2018 from 4,686,080 and 4,676,991, respectively, (as reported) to 1,338,880 and 1,336,283, respectively, (as revised). As a result, basic and diluted net loss per share attributable to common stockholders for the three and six months ended June 30, 2018 increased from $1.30 and $2.36, respectively, (as reported) to $4.57 and $8.24, respectively, (as revised). Management of the Company has concluded that these revisions of basic and diluted net loss per share attributable to common stockholders are not material to the previously issued interim financial statements.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 28, 2019

Risk of Concentrations of Credit, Significant Customers and Significant Suppliers

Use of Estimates

Significant customers are those that accounted for 10% or more of the Company’s total revenue or accounts receivable (see Note 16).

Deferred Offering Costs

Deferred Financing Costs

Cash Equivalents

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

Restricted Cash

Accounts Receivable

Property and Equipment

		Estimated Useful Life
Manufacturing equipment		5 years
OCS Consoles loaned to customers		5 years
Computer equipment and software		3 years
Laboratory equipment		3 years
Office and trade show equipment		5 years
Leasehold improvements		Shorter of term of lease or 15 years

Impairment of Long-Lived Assets

Software Development Costs

Inventory

Deferred Rent

Fair Value Measurements

•

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

•

Marketable Securities

Classification of Convertible Preferred Stock

Preferred Stock Warrant Liability

Segment Information

Product Warranties

Revenue Recognition

Performance Obligations

The primary performance obligations in the Company’s customer arrangements from which it derives revenue are as follows:

•

Payments Made to Customers

Variable Consideration

Revenue from reimbursements of out-of-pocket expenses, including travel, lodging, and meals, is accounted for as variable consideration.

Contract Assets and Liabilities

Disaggregated Revenue

	December 28, 2019		December 29, 2018
Gross revenue from sales to customers	$	25,844	$	14,657
Less: Clinical trial payments reducing revenue		2,240		1,640
Total net revenue	$	23,604	$	13,017

	December 28, 2019		December 29, 2018
Net revenue by OCS product:
OCS Lung net revenue	$	8,664	$	5,078
OCS Heart net revenue		11,442		5,956
OCS Liver net revenue		3,498		1,983
Total net revenue	$	23,604	$	13,017

	December 28, 2019		December 29, 2018
Net revenue by geography:
United States	$	16,253	$	6,543
Outside the U.S.		7,351		6,474
Total net revenue	$	23,604	$	13,017

Practical Expedients Used in Application of ASC 606

The Company has elected to apply the practical expedient for shipping. Accordingly, the Company does not consider shipping to be a contract performance obligation.

Distributors

Research, Development and Clinical Trials Costs

Patent Costs

Foreign Currency Translation

Stock-based Compensation

Stock-Based Compensation

Comprehensive Loss and Accumulated Other Comprehensive Loss

Net Income (Loss) per Share

Income Taxes

Recently Adopted Accounting Pronouncements

Recently Issued Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 28, 2019

Schedule of Estimated Useful Life of Assets

		Estimated Useful Life
Manufacturing equipment		5 years
OCS Consoles loaned to customers		5 years
Computer equipment and software		3 years
Laboratory equipment		3 years
Office and trade show equipment		5 years
Leasehold improvements		Shorter of term of lease or 15 years

Schedule of Recognized Revenue Net of Payments

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

	December 28, 2019		December 29, 2018
Gross revenue from sales to customers	$	25,844	$	14,657
Less: Clinical trial payments reducing revenue		2,240		1,640
Total net revenue	$	23,604	$	13,017

Schedule of Net revenue by OCS product

	December 28, 2019		December 29, 2018
Net revenue by OCS product:
OCS Lung net revenue	$	8,664	$	5,078
OCS Heart net revenue		11,442		5,956
OCS Liver net revenue		3,498		1,983
Total net revenue	$	23,604	$	13,017

	December 28, 2019		December 29, 2018
Net revenue by geography:
United States	$	16,253	$	6,543
Outside the U.S.		7,351		6,474
Total net revenue	$	23,604	$	13,017

Marketable Securities and Fair Value Measurements (Tables)

12 Months Ended

Dec. 28, 2019

Marketable Securities And Fair Value Measurements [Abstract]

Components of Marketable Securities by Security Type

Marketable securities by security type consisted of the following (in thousands):

	December 28, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities (due within one year)	$	23,318	$	17	$	—		$	23,335
U.S. government agency bonds (due within one year)		37,224		39		(2	)	$	37,261
	$	60,542	$	56	$	(2	)	$	60,596

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis (in thousands):

	Fair Value Measurements at December 28, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	11,760	$	—	$	—	$	11,760
Marketable securities:
U.S. Treasury securities		—		23,335		—		23,335
U.S. government agency bonds		—		37,261		—		37,261
	$	11,760	$	60,596	$	—	$	72,356

	Fair Value Measurements at December 29, 2018 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	13,586	$	—	$	—	$	13,586
	$	13,586	$	—	$	—	$	13,586
Liabilities:
Preferred stock warrant liability	$	—	$	—	$	898	$	898

Schedule of Fair Value Adjustment For Preferred Stock Warrants And Rights outstanding

The following table provides a roll-forward of the aggregate fair values of the Company’s preferred stock warrants for which fair value is determined by Level 3 inputs (in thousands):

	Preferred Stock Warrant Liability
Fair value at December 30, 2017	$	353
Change in fair value		545
Fair value at December 29, 2018	$	898
Change in fair value		341
Reclassification of warrant liability to equity upon initial public offering		(1,239	)
Fair value at December 28, 2019	$	—

Inventory (Tables)

12 Months Ended

Dec. 28, 2019

Inventory Disclosure [Abstract]

Schedule of Inventory, Current

Inventory consisted of the following (in thousands):

	December 28, 2019		December 29, 2018
Raw materials	$	4,881	$	3,817
Work-in-process		903		882
Finished goods		5,432		4,578
	$	11,216	$	9,277

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 28, 2019

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment, Net

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

	December 28, 2019			December 29, 2018
Manufacturing equipment	$	1,408		$	1,235
OCS Consoles loaned to customers		6,005			3,898
Computer equipment and software		1,273			1,087
Laboratory equipment		524			512
Office and trade show equipment		177			173
Leasehold improvements		1,319			1,319
Construction-in-progress		433			387
	$	11,139		$	8,611
Less: Accumulated depreciation and amortization		(6,347	)		(5,137	)
	$	4,792		$	3,474

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 28, 2019

Accrued Expenses And Other Current Liabilities [Abstract]

Schedule of Accrued expenses and other current liabilities

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

	December 28, 2019		December 29, 2018
Accrued research, development and clinical trials expenses	$	3,144	$	1,853
Accrued payroll and related expenses		3,604		1,729
Accrued financing fees (Note 13)		120		1,466
Accrued professional fees		537		549
Accrued premium for manufacturing contract (Note 13)		—		1,089
Accrued other		927		492
	$	8,332	$	7,178

Long-term Debt (Tables)

12 Months Ended

Dec. 28, 2019

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

As of December 28, 2019 and December 29, 2018, long-term debt consisted of the following (in thousands):

	December 28, 2019			December 29, 2018
Principal amount of long-term debt	$	35,000		$	35,000
Less: Current portion of long-term debt		—			—
Long-term debt, net of current portion		35,000			35,000
Debt discount, net of accretion		(1,139	)		(1,424	)
Accrued end-of-term payments		285			94
Long-term debt, net of discount and current portion	$	34,146		$	33,670

Convertible Preferred Stock [Abstract]

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 28, 2019

Schedule of Preferred Stock

As of December 29, 2018, Preferred Stock consisted of the following (in thousands, except share amounts):

	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Preference		Common Stock Issuable Upon Conversion
Series A-1 Preferred Stock		13,332		13,332	$	3,333	$	33		984
Series B Preferred Stock		3,771,020		3,624,650		10,691		12,382		286,102
Series B-1 Preferred Stock		2,560,245		2,560,245		8,746		8,746		202,086
Series C Preferred Stock		6,198,057		6,198,057		14,970		15,495		1,770,873
Series D Preferred Stock		14,740,000		14,565,000		34,868		72,825		4,161,428
Series E Preferred Stock		6,562,232		6,562,232		29,865		29,966		1,874,923
Series F Preferred Stock		16,931,168		16,880,624		84,046		84,234		4,823,028
		50,776,054		50,404,140	$	186,519	$	223,681		13,119,424

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

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65888546&loc=d3e21300-112643

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21553-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21488-112644

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(27))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21484-112644

Reference 14: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 28, 2019

Stockholders Equity Note [Abstract]

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Risk-free interest rate	2.29%				2.91	%
Expected term (in years)		6.02			6.06
Expected volatility	52%				51	%
Expected dividend yield		0	%		0	%

Summary of Stock Option Activity

The following table summarizes the Company’s option activity since December 29, 2018:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 29, 2018		1,625,758		$	1.76		5.8	$	20,726
Granted		463,357			16.68
Exercised		(124,226	)		1.60
Forfeited		(12,589	)		3.23
Outstanding as of December 28, 2019		1,952,300		$	5.31		5.87	$	26,415
Vested and expected to vest as of December 28, 2019		1,952,300		$	5.31		5.87	$	26,415
Options exercisable as of December 28, 2019		1,285,242		$	1.91		4.34	$	21,735

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):

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Cost of revenue	$	17	$	7
Research, development and clinical trials expenses		104		42
Selling, general and administrative expenses		733		95
	$	854	$	144

Income Taxes (Tables)

12 Months Ended

Dec. 28, 2019

Income Tax Disclosure [Abstract]

Schedule of Income (loss) Before Income Taxes

Income (loss) before income taxes consisted of the following (in thousands):

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
United States	$	(33,668	)	$	(23,919	)
Foreign		161			204
	$	(33,507	)	$	(23,715	)

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

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

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Federal statutory income tax rate		(21.0	)%		(21.0	)%
State taxes, net of federal benefit		(6.2	)%		(5.8	)%
Federal and state research and development tax credits		(2.8	)%		(3.0	)%
Nondeductible items		0.2	%		1.4	%
Other		0.9	%		0.5	%
Change in deferred tax asset valuation allowance		29.0	%		28.1	%
Effective income tax rate		0.1	%		0.2	%

Schedule of Net deferred Tax Assets

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

	December 28, 2019			December 29, 2018
Deferred tax assets:
Net operating loss carryforwards	$	74,206		$	63,041
Capitalized research and development expense		8,505			10,863
Research and development tax credit carryforwards		10,745			9,818
Accrued expenses		1,309			1,161
Stock-based compensation expense		243			260
Deferred rent		157			227
Total deferred tax assets		95,165			85,370
Deferred tax liabilities:
Other		(141	)		(54	)
Total deferred tax liabilities		(141	)		(54	)
Valuation allowance		(95,024	)		(85,316	)
Net deferred tax assets	$	—		$	—

Summary Changes in the Valuation Allowance for Deferred Tax Assets

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Valuation allowance as of beginning of year	$	(85,316	)	$	(78,650	)
Decreases recorded as benefit to income tax provision		—			—
Increases recorded to income tax provision		(9,708	)		(6,666	)
Valuation allowance as of end of year	$	(95,024	)	$	(85,316	)

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 28, 2019

Commitments And Contingencies Disclosure [Abstract]

Schedule of future minimum lease payments

Future minimum lease payments under operating leases as of December 28, 2019 are as follows (in thousands):

Fiscal Year Ending:
December 26, 2020	$	1,570
December 25, 2021		1,589
	$	3,159

Net Loss per Share (Tables)

12 Months Ended

Dec. 28, 2019

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Net Loss per Share Attributable to Common Stockholders

Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts):

	Fiscal Year Ended
	December 28, 2019			December 29, 2018
Numerator:
Net loss attributable to common stockholders	$	(33,547	)	$	(23,756	)
Denominator:
Weighted average common shares outstanding, basic and diluted		14,204,787			1,358,694
Net loss per share attributable to common stockholders, basic and diluted	$	(2.36	)	$	(17.48	)

Schedule of Computation of Diluted Net Loss per Share Attributable to Common Stockholders

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

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Convertible preferred stock (as converted to common stock)		—		13,119,424
Warrants to purchase convertible preferred stock (as converted to common stock)		—		64,440
Warrants to purchase common stock		64,440		—
Options to purchase common stock		1,952,300		1,625,798
		2,016,740		14,809,662

Segment Reporting and Geographic Data (Tables)

12 Months Ended

Dec. 28, 2019

Segment Reporting [Abstract]

Net revenue by OCS product

Net revenue by OCS product is summarized as follows (in thousands):

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Net revenue by OCS product:
OCS Lung net revenue	$	8,664	$	5,078
OCS Heart net revenue		11,442		5,956
OCS Liver net revenue		3,498		1,983
Total net revenue	$	23,604	$	13,017

Schedule of Financial data by geographical area

Financial data by geographical area is summarized as follows (in thousands):

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Net revenue by country⁽¹⁾:
United States	$	16,253	$	6,543
United Kingdom		2,233		2,580
Germany		1,147		1,456
All other countries		3,971		2,438
Total net revenue	$	23,604	$	13,017

Long-lived assets by Country

	Fiscal Year Ended
	December 28, 2019		December 29, 2018
Long-lived assets by country⁽²⁾:
United States	$	4,007	$	2,567
All other countries		785		907
Total long-lived assets	$	4,792	$	3,474

(1)	Net revenue by country is categorized based on the location of the end customer.

(2)	The Company’s only long-lived assets consist of property and equipment, net of depreciation, which are categorized based on their location of domicile.

Significant Customer Concentrations (Tables)

12 Months Ended

Dec. 28, 2019

Customer Concentration [Abstract]

Schedule of Net revenue

*	Less than 10%

Schedule of Accounts receivable

	Accounts Receivable
	December 28, 2019	December 29, 2018
Company A	*		13	%
Company B	*		15	%

*	Less than 10%

Selected Quarterly Results of Operations Data (Unaudited) (Tables)

12 Months Ended

Dec. 28, 2019

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Statement of Operations Data

	Fiscal Three Months Ended
	Dec. 28, 2019			Sept. 28, 2019			June 29, 2019			Mar. 30, 2019			Dec. 29, 2018			Sept. 29, 2018			June 30, 2018			Mar. 31, 2018
Net revenue	$	6,057		$	7,205		$	5,666		$	4,676		$	3,544		$	4,039		$	2,915		$	2,519
Gross profit		3,741			4,216			3,333			2,573			1,499			2,132			1,179			924
Loss from operations		(8,694	)		(7,242	)		(7,705	)		(5,962	)		(6,361	)		(3,939	)		(5,156	)		(4,781	)
Net loss	$	(9,177	)		(8,280	)		(9,195	)		(6,895	)	$	(7,635	)	$	(5,105	)	$	(6,115	)	$	(4,901	)
Net loss per share (basic and diluted)	$	(0.43	)	$	(0.39	)	$	(0.70	)	$	(4.86	)	$	(5.48	)	$	(3.73	)	$	(4.57	)	$	(3.61	)

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	May 06, 2019	Dec. 28, 2019	Dec. 29, 2018
Convertible preferred stock conversion ratio		3.5-for-one
Equity Method Investment, Ownership Percentage		100.00%
Net loss		$ (33,547)	$ (23,756)
Accumulated deficit		(369,483)	$ (335,936)
Cash equivalents and marketable securities		$ 80,700
IPO [Member]
Stock Issued During Period, Shares, New Issues	6,543,500
Net proceeds from initial public offering	$ 91,400
Underwriting discounts and commissions and other offering costs	$ 6,000
Over-Allotment Option [Member]
Stock Issued During Period, Shares, New Issues	853,500

Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	May 06, 2019 USD ($)	Dec. 28, 2019 USD ($) Letter Segment	Dec. 29, 2018 USD ($) Security Letter	Dec. 30, 2017 USD ($)
Number of marketable securities \| Security			0
Deferred Offering Costs			$ 3,400,000
Letters of credit outstanding		$ 500,000	$ 500,000
Number of letters of credit maintained \| Letter		2	2
Restricted cash non-current		$ 500,000	$ 500,000
Cash, cash equivalents and restricted cash		20,592,000	20,741,000	$ 12,436,000
Allowance for doubtful accounts		0	0
Provisions for doubtful accounts		0	0
Write off accounts receivable balances		0	0
Impairment losses on long-lived assets		0	0
Capitalized software development costs		$ 0	0
Number of operating segments \| Segment		1
Term of product warranties		1 year
Product warranty description		The Company provides a one-year warranty on its OCS Consoles and disposable sets and replaces or repairs any OCS Console or disposable set that does not function in accordance with the product specifications
Clinical Trial Cost		$ 2,240,000	1,640,000
Research development and clinical trials expenses		1,200,000	600,000
Performance obligations totaled		$ 700,000	1,500,000
Income tax likelihood percentage, description		greater than 50%
Other Income (Expense) [Member]
Foreign currency transaction gains (losses)		$ (200,000)	(200,000)
IPO [Member]
Issuance costs	$ 6,000,000
Maximum [Member]
Product warranty accrual		$ 100,000	$ 100,000
Accounts Receivable [Member]
Concentration Risk, Percentage		10.00%
Revenue [Member] \| Maximum [Member]
Concentration Risk, Percentage		10.00%

Summary of Significant Accounting Policies - Schedule of Estimated Useful Life of Assets (Detail)	12 Months Ended
	Dec. 28, 2019
Manufacturing Equipment [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
OCS Consoles Loaned to Customers [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Office and Trade Show Equipment [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	Shorter of term of lease or 15 years

Summary of Significant Accounting Policies - Recognized revenue net of payments (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 28, 2019

Sep. 28, 2019

Jun. 29, 2019

Mar. 30, 2019

Dec. 29, 2018

Sep. 29, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 28, 2019

Dec. 29, 2018

Gross revenue from sales to customers

$ 25,844

$ 14,657

Clinical Trial Cost

2,240

1,640

$ 6,057

$ 7,205

$ 5,666

$ 4,676

$ 3,544

$ 4,039

$ 2,915

$ 2,519

$ 23,604

^[1]

$ 13,017

^[1]

[1]	Net revenue by country is categorized based on the location of the end customer.

Summary of Significant Accounting Policies - Net revenue by OCS product (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 28, 2019

Sep. 28, 2019

Jun. 29, 2019

Mar. 30, 2019

Dec. 29, 2018

Sep. 29, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 28, 2019

Dec. 29, 2018

$ 6,057

$ 7,205

$ 5,666

$ 4,676

$ 3,544

$ 4,039

$ 2,915

$ 2,519

$ 23,604

^[1]

$ 13,017

^[1]

United States

^[1]

16,253

6,543

Outside the U.S.

7,351

6,474

OCS Lung net revenue

8,664

5,078

OCS Heart net revenue

11,442

5,956

OCS Liver net revenue

$ 3,498

$ 1,983

[1]	Net revenue by country is categorized based on the location of the end customer.

Components of Marketable Securities by Security Type (Detail) $ in Thousands	Dec. 28, 2019 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Marketable Securities, Amortized Cost	$ 60,542
Marketable Securities, Gross Unrealized Gains	56
Marketable Securities, Gross Unrealized Losses	(2)
Marketable Securities, Fair Value	60,596
U.S. Treasury Securities (due within one year) [Member]
Schedule Of Available For Sale Securities [Line Items]
Marketable Securities, Amortized Cost	23,318
Marketable Securities, Gross Unrealized Gains	17
Marketable Securities, Fair Value	23,335
U.S. Government Agency Bonds (due within one year) [Member]
Schedule Of Available For Sale Securities [Line Items]
Marketable Securities, Amortized Cost	37,224
Marketable Securities, Gross Unrealized Gains	39
Marketable Securities, Gross Unrealized Losses	(2)
Marketable Securities, Fair Value	$ 37,261

Marketable Securities and Fair Value Measurements - Additional Information (Detail) - USD ($)		12 Months Ended
	May 06, 2019	Dec. 28, 2019	Dec. 29, 2018
Marketable securities		$ 0
IPO closing date	May 06, 2019
Warrants using fair value underlying common shares	$ 27.41
Series D Convertible Preferred Stock Member [Member]
Share Price			$ 6.21
Series F Convertible Preferred Stock Member [Member]
Share Price			$ 5.73
Measurement Input, Expected Dividend Rate [Member]
Based on the expected dividend yield		0.00%

Fair Value of Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Cash equivalents:
Money market funds	$ 11,760	$ 13,586
Marketable securities:
Marketable securities	60,596
Cash equivalents and marketable securities	72,356
Cash Equivalents, at Carrying Value		13,586
Liabilities:
Preferred stock warrant liability		898
Level 1 [Member]
Cash equivalents:
Money market funds	11,760	13,586
Marketable securities:
Cash equivalents and marketable securities	11,760
Cash Equivalents, at Carrying Value		13,586
Level 2 [Member]
Marketable securities:
Cash equivalents and marketable securities	60,596
Level 3 [Member]
Liabilities:
Preferred stock warrant liability		$ 898	$ 353
U.S. Treasury Securities [Member]
Marketable securities:
Marketable securities	23,335
U.S. Treasury Securities [Member] \| Level 2 [Member]
Marketable securities:
Marketable securities	23,335
U.S. Government Agency Bonds [Member]
Marketable securities:
Marketable securities	37,261
U.S. Government Agency Bonds [Member] \| Level 2 [Member]
Marketable securities:
Marketable securities	$ 37,261

Marketable Securities and Fair Value Adjustment For Preferred Stock Warrants And Rights outstanding (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Fair value at December 30, 2017	$ 898
Change in fair value of preferred stock warrant liability	341	$ 545
Fair value at December 29, 2018		898
Reclassification of warrant liability to equity upon initial public offering	(1,239)
Level 3 [Member]
Fair value at December 30, 2017	898	353
Change in fair value of preferred stock warrant liability	341	545
Fair value at December 29, 2018		$ 898
Reclassification of warrant liability to equity upon initial public offering	$ (1,239)

Inventory (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 4,881	$ 3,817
Work-in-process	903	882
Finished goods	5,432	4,578
Inventory, net	$ 11,216	$ 9,277

Inventory - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Inventory Disclosure [Abstract]
Inventory Transfer To Property Plant And Equipment	$ 2,146	$ 1,393

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 11,139	$ 8,611
Less: Accumulated depreciation and amortization	(6,347)	(5,137)
Property and equipment, net	4,792	3,474
Manufacturing Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,408	1,235
OCS Consoles Loaned To Customers [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,005	3,898
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,273	1,087
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	524	512
Office and Trade Show Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	177	173
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,319	1,319
Construction-In-Progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 433	$ 387

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Property Plant And Equipment [Line Items]
Depreciation and amortization expense	$ 1,222	$ 769
OCS Consoles Loaned To Customers [Member] \| Cost of Revenue [Member]
Property Plant And Equipment [Line Items]
Depreciation	$ 1,000	$ 600

Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued research, development and clinical trials expenses	$ 3,144	$ 1,853
Accrued payroll and related expenses	3,604	1,729
Accrued financing fees (Note 13)	120	1,466
Accrued professional fees	537	549
Accrued premium for manufacturing contract (Note 13)		1,089
Accrued other	927	492
Accrued Expenses And Other Liabilities Current	$ 8,332	$ 7,178

Long-term Debt (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Debt Disclosure [Abstract]
Principal amount of long-term debt	$ 35,000	$ 35,000
Long-term debt, net of current portion	35,000	35,000
Debt discount, net of accretion	(1,139)	(1,424)
Accrued end-of-term payments	285	94
Long-term debt, net of discount and current portion	$ 34,146	$ 33,670

Long-term Debt - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Jun. 30, 2018	Aug. 31, 2016	Dec. 28, 2019	Dec. 29, 2018	May 06, 2019	Dec. 26, 2015
Basis spread on variable rate			8.50%
Warrants exercise price					$ 27.41
Repayments of long-term debt				$ 9,076
Loss on extinguishment of debt				(305)
Long-term debt			$ 35,000	$ 35,000
Description of variable rate basis			London Interbank Offered Rate (“LIBOR”), subject to a minimum of 1.0% and a maximum of 4.0%
Interest rate effective percentage			10.63%
Prepayment premium percentage			9.00%
Prepayment percentage			3.00%
Description of covenants			The covenants include maintaining a minimum liquidity amount of $3.0 million; the requirement, on an annual basis, to deliver to OrbiMed annual audited financial statements with an unqualified audit opinion from the Company’s independent registered public accounting firm; and restrictions on the Company’s activities, including limitations on dispositions, mergers or acquisitions; encumbering its intellectual property; incurring indebtedness or liens; paying dividends; making certain investments; and engaging in certain other business transactions.
Minimum liquidity covenant amount			$ 3,000
Average effective interest rate			12.36%
In Event Of Default [Member]
Increasing applicable margin			4.00%
Minimum [Member]
LIBOR Rate			1.00%
LIBOR plus the applicable margin, percentage			11.50%
Maximum [Member]
LIBOR Rate			4.00%
Interest rate effective percentage			11.50%
LIBOR plus the applicable margin, percentage			12.50%
Hercules [Member] \| Loan Agreement [Member]
Debt instrument, face amount						$ 8,500
Debt instrument, stated percentage		9.55%
Debt instrument, maturity month and year		2020-02
Debt instrument, end-of-term payment		$ 500
Debt instrument, interest-only payments, month and year		2017-12
Warrants expiration date		May 31, 2024
Repayments of long-term debt	$ 6,700
Hercules [Member] \| Loan Agreement [Member] \| Other Expense [Member]
Loss on extinguishment of debt	300
Hercules [Member] \| Loan Agreement [Member] \| Preferred Stock Warrant Liability [Member]
Fair value of warrant recognized as debt discount		$ 100
Hercules [Member] \| Loan Agreement [Member] \| Series F Convertible Preferred Stock Member [Member]
Warrant to purchase shares of preferred stock		34,068
Warrants exercise price		$ 4.99
Hercules [Member] \| Loan Agreement [Member] \| The Wall Street Journal Prime Rate [Member]
Basis spread on variable rate		4.25%
Orbi Med [Member]
Line of credit, aggregate maximum borrowing capacity	65,000
Long-term debt	35,000
Potential additional borrowings to be available upon achievement of specified conditions	$ 30,000
Orbi Med [Member] \| Debt Discount [Member]
Upfront fee paid			$ 900
OrbiMed and Third Parties [Member] \| Debt Discount [Member]
Other costs paid			$ 700

Convertible Preferred Stock - Additional Information (Detail) - shares	12 Months Ended
	Dec. 28, 2019	May 06, 2019	Dec. 29, 2018
Convertible Preferred Stock [Abstract]
Beneficial conversion feature, description	The Company also concluded that no beneficial conversion feature existed on the issuance date of each class of Preferred Stock.
Common Stock Issuable Upon Conversion		13,119,424	13,119,424

Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	May 06, 2019	Dec. 29, 2018
Preferred Stock Authorized		50,776,054
Preferred Stock Issued and Outstanding		50,404,140
Carrying Value		$ 186,519
Liquidation Preference		$ 223,681
Common Stock Issuable Upon Conversion	13,119,424	13,119,424
Series A-1 Preferred Stock
Preferred Stock Authorized		13,332
Preferred Stock Issued and Outstanding		13,332
Carrying Value		$ 3,333
Liquidation Preference		$ 33
Common Stock Issuable Upon Conversion		984
Series B Preferred Stock
Preferred Stock Authorized		3,771,020
Preferred Stock Issued and Outstanding		3,624,650
Carrying Value		$ 10,691
Liquidation Preference		$ 12,382
Common Stock Issuable Upon Conversion		286,102
Series B-1 Preferred Stock
Preferred Stock Authorized		2,560,245
Preferred Stock Issued and Outstanding		2,560,245
Carrying Value		$ 8,746
Liquidation Preference		$ 8,746
Common Stock Issuable Upon Conversion		202,086
Series C Preferred Stock
Preferred Stock Authorized		6,198,057
Preferred Stock Issued and Outstanding		6,198,057
Carrying Value		$ 14,970
Liquidation Preference		$ 15,495
Common Stock Issuable Upon Conversion		1,770,873
Series D Preferred Stock
Preferred Stock Authorized		14,740,000
Preferred Stock Issued and Outstanding		14,565,000
Carrying Value		$ 34,868
Liquidation Preference		$ 72,825
Common Stock Issuable Upon Conversion		4,161,428
Series E Preferred Stock
Preferred Stock Authorized		6,562,232
Preferred Stock Issued and Outstanding		6,562,232
Carrying Value		$ 29,865
Liquidation Preference		$ 29,966
Common Stock Issuable Upon Conversion		1,874,923
Series F Preferred Stock
Preferred Stock Authorized		16,931,168
Preferred Stock Issued and Outstanding		16,880,624
Carrying Value		$ 84,046
Liquidation Preference		$ 84,234
Common Stock Issuable Upon Conversion		4,823,028

Warrants to Purchase Preferred Stock - Additional Information (Detail)	May 06, 2019 $ / shares shares
Preferred Stock Warrants Shares Issued Upon Conversion	64,440
Exercise Price of $8.75 Per Share [Member]
Preferred Stock Warrants Shares Issued Upon Conversion	50,000
Preferred Stock Warrants Convertible Conversion Price \| $ / shares	$ 8.75
Exercise Price of $17.47 Per Share [Member]
Preferred Stock Warrants Shares Issued Upon Conversion	14,440
Preferred Stock Warrants Convertible Conversion Price \| $ / shares	$ 17.47

Equity - Additional Information (Detail)		12 Months Ended
Equity - Additional Information (Detail)	May 06, 2019 Vote $ / shares shares	Dec. 28, 2019 $ / shares shares	Dec. 29, 2018 $ / shares shares
Class Of Stock [Line Items]
Shares authorized \| shares	175,000,000
Preferred Stock, Shares Authorized \| shares	25,000,000	25,000,000	0
Preferred stock, no par value
Common stock, voting rights		Each share of common stock is entitled to one vote on all matters submitted to a vote of the Company’s stockholders.
Common stock, dividends declared		$ 0
Common stock, dividends paid		$ 0
Number of vote entitled for each share of common stock \| Vote	1
Common Stock No Par Value [Member]
Class Of Stock [Line Items]
Common stock, shares authorized \| shares	150,000,000	150,000,000	0
Common stock, no par value

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Apr. 15, 2019	Dec. 28, 2019	Dec. 29, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		463,357
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 16.68
Aggregate intrinsic value of stock options exercised		$ 2.3
Weighted average grant-date fair value of stock options granted		$ 8.55	$ 0.88
Performance-based Vesting [Member]
Shares granted to employees		0
2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
2019 Stock Plan [Member]
Shares available for future issuance	3,428,571	2,981,866
2019 Stock Incentive Plan [Member] \| Common Stock \| Employees and Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		463,357
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 8.55
2019 Employee Stock Purchase Plan [Member]
Unrecognized compensation cost related to unvested employee and director stock-based awards		$ 3.8
Weighted average period for unrecognized compensation cost		2 years 9 months
2019 Employee Stock Purchase Plan [Member] \| Board of Directors Chairman [Member]
Shares available for future issuance	371,142	371,142
Number of shares issued		0
Minimum [Member] \| 2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Maximum [Member]
Aggregate intrinsic value of stock options exercised			$ 0.2
Maximum [Member] \| 2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
Maximum [Member] \| 2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	1,595,189

Stock-Based Compensation - Assumptions Used to Determine Grant Date Fair Value of Stock Options Granted (Detail)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Stockholders Equity Note [Abstract]
Risk-free interest rate	2.29%	2.91%
Expected term (in years)	6 years 7 days	6 years 21 days
Expected volatility	52.00%	51.00%
Expected dividend yield	0.00%	0.00%

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Number of Shares
Beginning Balance	1,625,758
Granted	463,357
Exercised	(124,226)
Forfeited	(12,589)
Ending Balance	1,952,300	1,625,758
Vested and expected to vest as of December 28, 2019	1,952,300
Options exercisable as of December 28, 2019	1,285,242
Weighted Average Exercise Price
Beginning Balance	$ 1.76
Granted	16.68
Exercised	1.60
Forfeited	3.23
Ending Balance	5.31	$ 1.76
Vested and expected to vest as of December 28, 2019	5.31
Options exercisable as of December 28, 2019	$ 1.91
Weighted Average Contractual Term
Options Outstanding	5 years 10 months 13 days	5 years 9 months 18 days
Vested and expected to vest as of December 28, 2019	5 years 10 months 13 days
Options exercisable as of December 28, 2019	4 years 4 months 2 days
Aggregate Intrinsic Value
Options Outstanding	$ 26,415	$ 20,726
Vested and expected to vest as of December 28, 2019	26,415
Options exercisable as of December 28, 2019	$ 21,735

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Allocated Share-based Compensation Expense	$ 854	$ 144
Cost of revenue [Member]
Allocated Share-based Compensation Expense	17	7
Research, development and clinical trials expenses [Member]
Allocated Share-based Compensation Expense	104	42
Selling, general and administrative expenses [Member]
Allocated Share-based Compensation Expense	$ 733	$ 95

Income Taxes - Additional Information (Detail) - USD ($)		12 Months Ended
	Dec. 22, 2017	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income Taxes [Line Items]
Federal corporate income tax rate	35.00%	21.00%	21.00%
Percentage of limitation of deduction for net operating losses of taxable income		80.00%
Income tax benefits		$ 0	$ 0	$ 0
Operating loss carryforwards, limitations on use		These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income or tax liabilities. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period.
Valuation allowance		$ 95,024,000	85,316,000	$ 78,650,000
Unrecognized tax benefits		0	0
Unrecognized tax benefits, related interest and penalties accrued		0	0
Accrued interest or penalties related to uncertain tax positions		0	0
U.S. Federal [Member]
Income Taxes [Line Items]
Operating loss carryforwards		$ 287,800,000
Operating loss carryforwards begin to expire		2020
Indefinite operating loss carryforwards		$ 72,800,000
U.S. Federal [Member] \| Research and Development Credit Carry Forwards [Member]
Income Taxes [Line Items]
Tax credit carryforwards		$ 7,000,000
Tax credits carryforwards begin to expire		2020
State [Member]
Income Taxes [Line Items]
Operating loss carryforwards		$ 217,800,000
Operating loss carryforwards begin to expire		2030
State [Member] \| Research and Development Credit Carry Forwards [Member]
Income Taxes [Line Items]
Tax credit carryforwards		$ 4,700,000
Tax credits carryforwards begin to expire		2024
Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards		$ 0
Maximum [Member]
Income Taxes [Line Items]
Foreign income tax provision		$ 100,000	$ 100,000
Minimum [Member]
Income Taxes [Line Items]
Percentage of change in ownership for operating loss carryforward		50.00%
Period for change in ownership percentage		3 years

Income Taxes - Schedule of Income (loss) Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Income Tax Disclosure [Abstract]
United States	$ (33,668)	$ (23,919)
Foreign	161	204
Loss before income taxes	$ (33,507)	$ (23,715)

Income Taxes - Reconciliation of U.S. Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate (Detail)		12 Months Ended
	Dec. 22, 2017	Dec. 28, 2019	Dec. 29, 2018
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	(35.00%)	(21.00%)	(21.00%)
State taxes, net of federal benefit		(6.20%)	(5.80%)
Federal and state research and development tax credits		(2.80%)	(3.00%)
Nondeductible items		0.20%	1.40%
Other		0.90%	0.50%
Change in deferred tax asset valuation allowance		29.00%	28.10%
Effective income tax rate		0.10%	0.20%

Income Taxes - Schedule of Net deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Deferred tax assets:
Net operating loss carryforwards	$ 74,206	$ 63,041
Capitalized research and development expense	8,505	10,863
Research and development tax credit carryforwards	10,745	9,818
Accrued expenses	1,309	1,161
Stock-based compensation expense	243	260
Deferred rent	157	227
Total deferred tax assets	95,165	85,370
Deferred tax liabilities:
Other	(141)	(54)
Total deferred tax liabilities	(141)	(54)
Valuation allowance	$ (95,024)	$ (85,316)	$ (78,650)

Income Taxes - Summary of Changes in the Valuation Allowance for Deferred Tax Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Income Tax Disclosure [Abstract]
Valuation allowance as of beginning of year	$ 85,316	$ 78,650
Increases recorded to income tax provision	(9,708)	(6,666)
Valuation allowance as of end of year	$ 95,024	$ 85,316

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Rent expense	$ 1,200	$ 1,200
Payments for royalties	300	200
Royalty payable	100
Accrued professional fees	537	549
Series B Preferred Stock and Series D Preferred Stock [Member]
Accrued professional fees		$ 1,500
Maximum [Member]
Guaranteed minimum annual royalty payment	$ 100

Commitments and Contingencies (Detail) $ in Thousands	Dec. 28, 2019 USD ($)
Commitments And Contingencies Disclosure [Abstract]
December 26, 2020	$ 1,570
December 25, 2021	1,589
Future minimum payments due	$ 3,159

Net Loss per Share - Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018	Dec. 28, 2019	Dec. 29, 2018
Numerator:
Net loss attributable to common stockholders	$ (9,177)	$ (8,280)	$ (9,195)	$ (6,895)	$ (7,635)	$ (5,105)	$ (6,115)	$ (4,901)		$ (33,547)	$ (23,756)
Denominator:
Weighted average common shares outstanding, basic and diluted							1,338,880		1,336,283	14,204,787	1,358,694
Net loss per share attributable to common stockholders, basic and diluted	$ (0.43)	$ (0.39)	$ (0.70)	$ (4.86)	$ (5.48)	$ (3.73)	$ (4.57)	$ (3.61)	$ (8.24)	$ (2.36)	$ (17.48)

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

+ References + Details

Net Loss per Share - Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,016,740	14,809,662
Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		13,119,424
Warrants to Purchase Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		64,440
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	64,440
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,952,300	1,625,798

Segment Reporting and Geographic Data - Additional Information (Detail)	12 Months Ended
	Dec. 28, 2019 Segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment Reporting and Geographic Data - Net revenue by OCS product (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 28, 2019

Sep. 28, 2019

Jun. 29, 2019

Mar. 30, 2019

Dec. 29, 2018

Sep. 29, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 28, 2019

Dec. 29, 2018

$ 6,057

$ 7,205

$ 5,666

$ 4,676

$ 3,544

$ 4,039

$ 2,915

$ 2,519

$ 23,604

^[1]

$ 13,017

^[1]

OCS Lung net revenue

8,664

5,078

OCS Heart net revenue

11,442

5,956

OCS Liver net revenue

$ 3,498

$ 1,983

[1]	Net revenue by country is categorized based on the location of the end customer.

Segment Reporting and Geographic Data - Financial data by geographical area (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 28, 2019

Sep. 28, 2019

Jun. 29, 2019

Mar. 30, 2019

Dec. 29, 2018

Sep. 29, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 28, 2019

Dec. 29, 2018

$ 6,057

$ 7,205

$ 5,666

$ 4,676

$ 3,544

$ 4,039

$ 2,915

$ 2,519

$ 23,604

^[1]

$ 13,017

^[1]

United States

^[1]

16,253

6,543

UNITED KINGDOM

^[1]

2,233

2,580

GERMANY

^[1]

1,147

1,456

All other countries

Geographic Areas, Long-Lived Assets [Abstract]

^[1]

$ 3,971

$ 2,438

[1]	Net revenue by country is categorized based on the location of the end customer.

Segment Reporting and Geographic Data - Geographic Areas Long Lived Assets (Detail) - USD ($)
$ in Thousands

Dec. 28, 2019

Dec. 29, 2018

Long-lived assets

^[1]

$ 4,792

$ 3,474

United States

Geographic Areas, Long-Lived Assets [Abstract]

Long-lived assets

^[1]

4,007

2,567

All other countries

Geographic Areas, Long-Lived Assets [Abstract]

Long-lived assets

^[1]

$ 785

$ 907

[1]	The Company’s only long-lived assets consist of property and equipment, net of depreciation, which are categorized based on their location of domicile.

Significant Customer Concentrations - Additional Information (Detail)	12 Months Ended
	Dec. 28, 2019
Accounts Receivable [Member]
Concentration Risk, Percentage	10.00%
Maximum [Member] \| Revenue [Member]
Concentration Risk, Percentage	10.00%

Significant Customer Concentrations - Net revenue (Detail) - Customer Concentration Risk [Member] - Revenue [Member]	12 Months Ended
	Dec. 29, 2018
Company A [Member]
Concentration Risk, Percentage	10.00%
Company B [Member]
Concentration Risk, Percentage	10.00%

Significant Customer Concentrations - Accounts receivable (Detail) - Accounts Receivable [Member]	12 Months Ended
	Dec. 29, 2018
Company A [Member]
Concentration Risk, Percentage	13.00%
Company B [Member]
Concentration Risk, Percentage	15.00%

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Director [Member]
Compensation Expense	$ 0.2	$ 0.2

Subsequent Events - Additional Information (Details) - Omnibus Amendment #1 - Subsequent Event [Member] $ in Millions	Jan. 09, 2020 USD ($) ft²
Subsequent Event [Line Items]
Lease agreement effective date	Jun. 25, 2004
Area of office space \| ft²	39,744
Area of operational space \| ft²	11,735
Extended lease terms at existing lease rates	2026-12
Extended lease term	5 years
Lease existence of option to extend	true
Landlord’s contribution for leasehold improvements , amount \| $	$ 3.4
Lease annual base rent \| $	$ 1.9
Percentage of annual base rent increase	2.50%

Selected Quarterly Results of Operations Data -Summary of Quarterly Statement of Operations Data (Detail) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

6 Months Ended

12 Months Ended

Dec. 28, 2019

Sep. 28, 2019

Jun. 29, 2019

Mar. 30, 2019

Dec. 29, 2018

Sep. 29, 2018

Jun. 30, 2018

Mar. 31, 2018

Jun. 30, 2018

Dec. 28, 2019

Dec. 29, 2018

Quarterly Financial Information Disclosure [Abstract]

Net loss per share (basic and diluted)

$ 6,057

$ 7,205

$ 5,666

$ 4,676

$ 3,544

$ 4,039

$ 2,915

$ 2,519

$ 23,604

^[1]

$ 13,017

^[1]

Gross profit

3,741

4,216

3,333

2,573

1,499

2,132

1,179

924

13,863

5,734

Loss from operations

(8,694)

(7,242)

(7,705)

(5,962)

(6,361)

(3,939)

(5,156)

(4,781)

(29,603)

(20,237)

Net loss

$ (9,177)

$ (8,280)

$ (9,195)

$ (6,895)

$ (7,635)

$ (5,105)

$ (6,115)

$ (4,901)

$ (33,547)

$ (23,756)

$ (0.43)

$ (0.39)

$ (0.70)

$ (4.86)

$ (5.48)

$ (3.73)

$ (4.57)

$ (3.61)

$ (8.24)

$ (2.36)

$ (17.48)

[1]	Net revenue by country is categorized based on the location of the end customer.