Note 2 - Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Notes to Financial Statements

Significant Accounting Policies [Text Block]

2.         Summary of Significant Accounting Policies

Basis of Presentation

The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of the Company and its direct and indirect wholly owned subsidiaries. All inter-company accounts and transactions have been eliminated in consolidation.

Reclassifications

Certain amounts reported previously have been reclassified to conform to the current year presentation, with no effect on stockholders’ equity or net loss as previously reported. These reclassifications relate to the (gain) loss on extinguishment of debt which was historically included in interest expense on the consolidated statements of operations for the year ended December 31, 2019.

Liquidity

The Company had an accumulated deficit of $785.4 million and working capital of $103.4 million as of December 31, 2021. The Company has not established sufficient sales revenues to cover its operating costs and believes it may require additional capital in the future to proceed with its operating plan.

The Company believes the COVID-19 pandemic will continue to negatively impact its operations and ability to implement its market development efforts, which will have a negative effect on its financial condition.

In 2021, the Company raised additional capital through equity offerings, including raising net proceeds of $73.4 million in a January 2021 public offering, $28.6 million in a January 2021 registered direct offering, and $27.3 million in an at-the-market offering launched in 2020 (the “2020 ATM Offering”). Additionally, in 2021, the Company launched the 2021 ATM Offering and raised proceeds, net of legal costs and commissions, of $2.8 million under this offering during the year ended December 31, 2021. Also, certain holders of our Series B, Series C, and D warrants to purchase shares of our common stock exercised such warrants in 2021 for aggregate proceeds to the Company of $30.6 million.

As of December 31, 2021, the Company had cash, cash equivalents, short-term and long-term investments, excluding restricted cash, of $135.8 million.

While the Company believes that its existing cash, cash equivalents, and short-term investments as of December 31, 2021 will be sufficient to sustain operations for at least the next 12 months from the issuance of these consolidated financial statements, the Company believes it may need to obtain additional financing in the future to proceed with its business plan. Management's plan to obtain additional resources for the Company may include additional sales of equity under the 2021 ATM Offering or otherwise, traditional financing, such as loans, entry into a strategic collaboration, entry into an out-licensing arrangement or provision of additional distribution rights in some or all of our markets. However, management cannot provide any assurance that the Company will be successful in accomplishing any or all of its plans and be able to secure additional funding when needed on terms acceptable to the Company, or at all. 

Risk and Uncertainties

The Company is subject to risks similar to other similarly sized companies in the medical device industry. These risks include, without limitation: potential negative impacts on the Company's operations caused by the COVID-19 pandemic, including new variants of the virus; the historical lack of profitability; the Company’s ability to raise additional capital; the success of its market development efforts, the liquidity and capital resources of its partners; its ability to successfully develop, clinically test and commercialize its products; the timing and outcome of the regulatory review process for its products; changes in the health care and regulatory environments of the United States, the European Union, Japan, Taiwan, and other countries in which the Company operates or intends to operate; its ability to attract and retain key management, marketing and scientific personnel; its ability to successfully prepare, file, prosecute, maintain, defend and enforce patent claims and other intellectual property rights; its ability to successfully transition from a research and development company to a marketing, sales and distribution company; competition in the market for robotic surgical devices; and its ability to identify and pursue development of additional products.

The COVID-19 pandemic had a significant impact on the Company in 2021 and continues to have a significant impact on its operations, primarily due to the continued repeated temporary cessation of elective surgical procedures in many markets, and the challenges and restrictions caused by stay-at-home orders, social distancing requirements and travel restrictions. The Company’s business and customers were negatively impacted by the COVID-19 pandemic, which suspended many elective surgical procedures globally, curtailed travel and necessarily diverted the attention of hospital customers. A variety of travel restrictions have caused delays in product installation and training activities. This has significantly impacted the Company’s ability to implement its market development activities to place Senhance Systems, provide training, and increase the use of the Senhance Systems in place. Given the dynamic nature of this health emergency, the full impact of the COVID-19 pandemic on ongoing business, results of operations and overall financial performance cannot be reasonably estimated at this time.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include impairment considerations for long- term assets, fair value estimates related to contingent consideration, warrant liabilities, stock compensation expense, revenue recognition, accounts receivable reserves, short-term and long-term investments, excess and obsolete inventory reserves, inventory classification between current and non-current, measurement of lease liabilities and corresponding right-of-use (“ROU”) assets, and deferred tax asset valuation allowances.

Principles of Consolidation and Foreign Currency Considerations

The accompanying consolidated financial statements include the accounts of the Company and its direct and indirect wholly owned subsidiaries, Asensus Surgical US, Inc., Asensus International, Inc., Asensus Surgical Italia S.r.l., Asensus Surgical Europe S.à.r.l., Asensus Surgical Taiwan Ltd., Asensus Surgical Japan K.K., Asensus Surgical Israel Ltd., Asensus Surgical Netherlands B.V., and Asensus Surgical Canada, Inc. All inter-company accounts and transactions have been eliminated in consolidation.

The functional currency of the Company’s operational foreign subsidiaries is predominantly the Euro. The assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars at exchange rates in effect at the balance sheet date. Income and expense items are translated at the average exchange rates prevailing during the period. The cumulative translation effect for a subsidiary using a functional currency other than the U.S. dollar is included in accumulated other comprehensive income or loss as a separate component of stockholders’ equity.

The Company’s intercompany accounts are denominated in the functional currency of the foreign subsidiary. Gains and losses resulting from the remeasurement of intercompany receivables that the Company considers to be of a long-term investment nature are recorded as a cumulative translation adjustment in accumulated other comprehensive income or loss as a separate component of stockholders’ equity, while gains and losses resulting from the remeasurement of intercompany receivables from a foreign subsidiary for which the Company anticipates settlement in the foreseeable future are recorded in the consolidated statements of operations and comprehensive loss. The net gains and losses included in net loss in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2021, 2020, and 2019 were not significant.

Cash and Cash Equivalents, Restricted Cash, and Investments

The Company considers all highly liquid investments with original maturities of 90 days or less at the time of purchase to be cash equivalents.

Restricted cash as of December 31, 2021 and 2020 includes $1.2 million and $1.2 million, respectively, in cash accounts held as collateral primarily under the terms of an office operating lease, credit cards, and automobile leases.

The Company’s investments as of December 31, 2021 consisted of commercial paper and corporate bonds and were classified as available-for-sale. Investments classified as available-for-sale are measured at fair value, and net unrealized gains and losses are recorded as a component of accumulated other comprehensive income (loss) on the consolidated balance sheets until realized. Realized gains and losses on sales of investment securities are determined based on the specific-identification method and are recorded in interest income, net. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity computed under the effective interest method. Such amortization and accretion is included in interest expense, net. The Company held no investments as of December 31, 2020. The Company recognized an immaterial amount of gross realized losses for the year ending December 31, 2021. There were no gross realized gains for the year ended December 31, 2021. There were no gross realized gain or losses recorded for the years ended December 31, 2020 and 2019. The Company reclassified an immaterial amount of unrealized losses from accumulated other comprehensive income (loss) for the year ended December 31, 2021 with no related reclassification for the years ended December 31, 2020 and 2019. Investments with remaining maturities at date of purchase greater than 90 days and remaining maturities as of the reporting period less than one year are classified as short-term investments. Investments with remaining maturities greater than one year are classified as long-term investments. 

Concentrations and Credit Risk

The Company’s principal financial instruments subject to potential concentration of credit risk are cash and cash equivalents, and investments, including amounts held in money market funds, commercial paper, and corporate bonds. The Company places cash deposits with a federally insured financial institution. The Company maintains its cash at banks and financial institutions it considers to be of high credit quality; however, the Company’s domestic cash deposits may at times exceed the Federal Deposit Insurance Corporation’s insured limit. Balances in excess of federally insured limitations may not be insured. The Company has not experienced losses on these accounts, and management believes that the Company is not exposed to significant risks on such accounts. Investments are stated at their estimated fair values, based on quoted market prices for the same or similar instruments. The counterparties to the agreements relating to the Company’s investments consist of various major corporations, financial institutions, and government agencies of high credit standing.

The Company’s accounts receivable are derived from sales and leases to customers located throughout the world. The Company evaluates its customers’ financial condition and, generally, requires no collateral from its customers. The Company provided reserves for potential credit losses and recorded $0.1 million, $0 million, and $1.6 million in bad debt charges during the years ended December 31, 2021, 2020 and 2019, respectively. The Company had three customers who constituted 61% of the Company’s net accounts receivable as of December 31, 2021. The Company had seven customers who constituted 68% of the Company’s net accounts receivable at December 31, 2020. The Company had two customers who accounted for 52% of revenue in 2021, nine customers who accounted for 55% of revenue in 2020, and six customers who accounted for 82% of revenue in 2019.  

Accounts Receivable

Accounts receivable are recorded at net realizable value, which includes an allowance for estimated uncollectible accounts. The allowance for uncollectible accounts was determined on a customer specific basis based on deemed collectability. The allowance for doubtful accounts was $1.7 million and $1.8 million as of December 31, 2021 and December 31, 2020, respectively.

Inventories

Inventories are stated at the lower of cost (determined on a first-in, first-out basis) or net realizable value. Inventory costs include direct materials, direct labor, and normal manufacturing overhead. The Company records reserves, when necessary, to reduce the carrying value of inventory to its net realizable value. Management considers forecast demand in relation to the inventory on hand, competitiveness of product offerings, market conditions and product life cycles when determining excess and obsolescence and net realizable value adjustments. At the point of loss recognition, a new, lower-cost basis for that inventory is established, and any subsequent improvements in facts and circumstances do not result in the restoration or increase in that newly established cost basis.

Any inventory on hand at the measurement date in excess of the Company's current requirements based on anticipated levels of sales is classified as long-term on the Company's consolidated balance sheets. The Company's classification of long-term inventory requires it to estimate the portion of on hand inventory that can be realized over the upcoming twelve months.

Identifiable Intangible Assets

Definite-Lived Intangible Assets - Intellectual Property

Intellectual property consists of purchased patent rights and developed technology acquired as part of a business acquisition. Developed technology includes reclassified in-process research and development (“IPR&D”) assets related to (i) the Senhance System acquired in 2015 and reclassified in 2017 and (ii) the MST acquisition in 2018 and reclassified in 2020. Amortization of the patent rights is recorded using the straight-line method over the estimated useful life of the patents of 10 years. Amortization of the developed technology is recorded using the straight-line method over the estimated useful life of 5 to 7 years.

The Company periodically evaluates intellectual property for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. To determine the recoverability, the Company evaluates the probability that future estimated undiscounted net cash flows will be less than the carrying amount of the assets. If such estimated cash flows are less than the carrying amount of the assets, then such assets are written down to their fair value. No impairment of intellectual property was identified during the year ended December 31, 2021, 2020 and 2019.

Indefinite-Lived Intangible Assets

IPR&D assets represent the fair value assigned to technologies that were acquired, which at the time of acquisition have not reached technological feasibility and have no alternative future use. IPR&D assets are considered to be indefinite-lived until the completion or abandonment of the associated research and development projects. During the period that the IPR&D assets are considered indefinite-lived, they are tested for impairment on an annual basis, or more frequently if the Company becomes aware of any events occurring or changes in circumstances that indicate that the fair value of the IPR&D assets are less than their carrying amounts. To determine the recoverability, the Company evaluates the probability that future estimated discounted net cash flows will be less than the carrying amount of the assets. If such estimated cash flows are less than the carrying amount of the assets, then such assets are written down to their fair value.

The Company reclassifies IPR&D assets to intellectual property when development is complete, which generally occurs upon regulatory approval when the Company is able to commercialize products. The completed IPR&D assets are then classified as definite-lived intangible assets and are amortized based on their estimated useful lives at that point in time. If development is terminated or abandoned, the Company may have a full or partial impairment charge related to the IPR&D assets, calculated as the excess of carrying value of the IPR&D assets over fair value.

The Company performed an impairment test of its IPR&D at the end of the third quarter 2019 as events and changes in market conditions indicated that the asset might be impaired. During the third quarter of 2019, the Company concluded that the fair value determined by the market value approach was lower than the carrying value and recognized a $7.9 million impairment charge to its IPR&D. The Company performed its annual impairment assessment at December 31, 2019 and no additional impairment was required. As of December 31, 2020, all IPR&D asset development was completed and reclassified to intellectual property.

Property and Equipment

Property and equipment consists primarily of operating lease Senhance System assets, machinery, manufacturing equipment, demonstration equipment, computer equipment, furniture, and leasehold improvements, and purchased software which are recorded at cost less accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets as follows:

	Years
Operating lease assets – Senhance System leasing			5
Machinery, manufacturing, and demonstration equipment		3	-	5
Computer equipment			3
Furniture			5
Leasehold improvements	Lesser of lease term or 3 to 10
Purchased Software			5

The Company reviews its property and equipment assets for possible impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be fully recoverable. To determine the recoverability of its long-lived assets, the Company evaluates the probability that future estimated undiscounted net cash flows will be less than the carrying amount of the assets. If such estimated cash flows are less than the carrying amount of the long-lived assets, then such assets are written down to their fair value. The Company did not identify any impairment during the years ended December 31, 2021, 2020, and 2019.

Operating Leases

We have operating leases for our corporate office buildings, vehicles, and machinery and equipment. At inception, we determine whether an agreement represents a lease and, at commencement, we evaluate each lease agreement to determine whether the lease constitutes an operating or financing lease.

On January 1, 2019, the Company adopted ASU No. 2016-02, applying the package of practical expedients to leases that commenced before the effective date whereby the Company elected to not reassess the following: (i) whether any expired or existing contracts contain leases; (ii) the lease classification for any expired or existing leases; and (iii) initial direct costs for any existing leases. The Company also elected, for all classes of underlying assets, to not separate non-lease components from lease components and instead to account for them as a single component. Non-lease components consist of common area maintenance payments for most real estate leases, which are determined based on costs incurred by the lessor. Many of the Company’s leases include base rental periods coupled with options to renew or terminate the lease, generally at the Company’s discretion.  In evaluating the lease term, the Company considers whether renewal is reasonably certain.  To the extent a significant economic incentive exists to renew the lease, the option is included within the lease term.  Based on the Company’s leases, renewal options generally do not provide a significant economic incentive and are therefore excluded from the lease term.

Adoption of ASU No. 2016-02 did not have a material impact on the Company’s cash flows from operations or the Company’s operating results. The most significant impact was the recognition of operating lease right-of-use assets and operating lease liabilities on our balance sheet. Lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, we utilize the appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Operating lease expense is recognized on a straight-line basis over the lease term, subject to any changes in the lease or expectations regarding the terms.

Employee Retention Tax Credit Receivable

The Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) included an Employee Retention Tax Credit (“ERTC”) provision designed to encourage employers to keep employees on their payroll.  The ERTC is a refundable tax credit against certain payroll taxes paid by employers for eligible wages.  We assessed the government assistance in accordance with Topic 958-605, Not for Profit Entities-Revenue Recognition, and concluded it represents a conditional non-exchange transaction that is recognized when the conditions have been substantially met. During the year ended December 31, 2021, we submitted an ERTC refund for $1.3 million and recorded the amount into Other Income (Expense) on the consolidated statements of operations and comprehensive loss. The Company believes the relevant conditions of the employee retention credit provision of the CARES Act have been substantially met and that it will receive the credit.

Notes Payable – Payroll Protection Program

The Company’s policy is to account for forgivable loans received through the U.S. Small Business Administration (the “SBA”) under the CARES Act Payroll Protection Program (“PPP”), as debt in accordance with ASC 470, Debt, and other related accounting pronouncements. The forgiveness of debt, in whole or part, is recognized once the debt is extinguished, which occurs when the Company is legally released from the liability by the SBA. Any portion of debt forgiven, adjusted for accrued interest forgiven and unamortized debt issuance costs, is recorded as a gain on extinguishment of debt, and presented in the consolidated statements of operations and comprehensive loss. On June 10, 2021, the Company received notification from the SBA that the principal amount of its PPP loan of $2.8 million and related interest had been forgiven.

Contingent Consideration

Contingent consideration is recorded as a liability and is the estimate of the fair value of potential milestone payments related to business acquisitions. Contingent consideration is measured at fair value using a Monte-Carlo simulation utilizing significant unobservable inputs including the probability of achieving each of the potential milestones, future Euro-to-USD exchange rates, revenue volatility and an estimated discount rate associated with the risks of the expected cash flows attributable to the various milestones. Significant increases or decreases in any of the probabilities of success or changes in expected achievement of any of these milestones would result in a significantly higher or lower fair value of these milestones, respectively, and commensurate changes to the associated liability. The contingent consideration is revalued at each reporting period and changes in fair value are recognized in the consolidated statements of operations and comprehensive loss.

On September 21, 2015, the Company completed the strategic acquisition, through its wholly owned subsidiary TransEnterix International, from Sofar S.p.A., an Italian company (“Sofar”), of all of the assets, employees and contracts related to the advanced robotic system for minimally invasive laparoscopic surgery now known as the Senhance System. Under the terms of the Purchase Agreement, as amended in 2016, as of December 31, 2021, the Company has accrued $2.4 million of estimated fair value of remaining contingent consideration related to a milestone of €15.0 million which shall be payable upon achievement of trailing revenues from sales or services contracts of the Senhance System of at least €25.0 million over a calendar quarter or in the event that (i) the Company or Asensus International is acquired, (ii) the Company significantly reduces or suspends selling efforts of the Senhance System, or (iii) the Company acquires a business that offers alternative products that are directly competitive with the Senhance System.

Warrant Liabilities

The Company’s Series B Warrants (see Note 16) were measured at fair value using a simulation model which took into account, as of the valuation date, factors including the current exercise price, the expected life of the warrant, the current price of the underlying stock, its expected volatility, holding cost and the risk-free interest rate for the term of the warrant. The warrant liability was revalued at each reporting period and changes in fair value were recognized in the consolidated statements of operations and comprehensive loss. The selection of the appropriate valuation model and the inputs and assumptions that are required to determine the valuation requires significant judgment and requires management to make estimates and assumptions that affect the reported amount of the related liability and reported amounts of the change in fair value. Actual results could differ from those estimates, and changes in these estimates are recorded when known. All remaining outstanding Series B Warrants were exercised in the first quarter 2021.

Revenue Recognition

The Company’s revenue consists of product revenue resulting from the sale and lease of Senhance Systems, Senhance System components, instruments and accessories, and service revenue. The Company accounts for a contract with a customer when there is a legally enforceable contract between the Company and the customer, the rights of the parties are identified, the contract has commercial substance, and collectability of the contract consideration is probable. The Company's revenues are measured based on consideration specified in the contract with each customer, net of any sales incentives and taxes collected from customers that are remitted to government authorities. The Company’s Senhance System sale arrangements generally include a five-year service period; the first year of service is generally free and included in the Senhance System sale arrangement and the remaining four years are generally included at a stated service price.

The Company’s Senhance System sale arrangements generally contain multiple products and services. For these consolidated sale arrangements, the Company accounts for individual products and services as separate performance obligations if they are distinct, which is if a product or service is separately identifiable from other items in the consolidated package, and if a customer can benefit from it on its own or with other resources that are readily available to the customer. The Company’s Senhance System sale arrangements may include a combination of the following performance obligations: system(s), system components, instruments, accessories, and system services.

For arrangements that contain multiple performance obligations, revenue is allocated to each performance obligation based on its relative estimated standalone selling price. When available, standalone selling prices are based on observable prices at which the Company separately sells the products or services; however due to limited sales to date, standalone selling prices generally are not directly observable. The Company estimates the standalone selling price using the market assessment approach considering market conditions and entity-specific factors including, but not limited to, features and functionality of the products and services, geographies, type of customer, and market conditions. The Company regularly reviews estimated standalone selling prices and updates these estimates if necessary.

The Company recognizes revenues when or as the performance obligations are satisfied by transferring control of the product or service to a customer. The Company generally recognizes revenue for the performance obligations as follows:

•   System sales. For Senhance Systems and Senhance System components sold directly to end customers (including those arising from Senhance System purchases under lease rights to purchase), revenue is recognized when the Company transfers control to the customer, which is generally at the point when acceptance occurs that indicates customer acknowledgment of delivery or installation, depending on the terms of the arrangement. For lease buyouts, where the customer has already acknowledged installation of the system, transfer of control occurs when the Company receives an executed contract for the lease buyout of the Senhance System. For Senhance Systems sold through distributors, for which distributors are responsible for installation, revenue is recognized generally at the time of shipment. The Company’s Senhance System arrangements generally do not provide a right of return. The Senhance Systems are generally covered by a one-year warranty. Warranty costs were not material for the periods presented.

•   Instruments and accessories. Revenue from sales of instruments and accessories is recognized when control is transferred to the customers, which generally occurs at the time of shipment, but also occurs at the time of delivery depending on the customer arrangement.

•   Service. Service revenue is recognized ratably over the term of the service period as the customers benefit from the service throughout the service period. Revenue related to services performed on a time-and-materials basis is recognized when performed.

The following table presents revenue disaggregated by type and geography:

	Years Ended December 31,
	2021		2020		2019
	(in thousands)
U.S.
Systems	$	380	$	282	$	90
Instruments and accessories		270		187		108
Services		383		380		338
Total U.S. revenue		1,033		849		536
Outside of U.S. ("OUS")
Systems		4,363		490		5,459
Instruments and accessories		1,699		653		1,447
Services		1,137		1,183		1,089
Total OUS revenue		7,199		2,326		7,995
Total
Systems		4,743		772		5,549
Instruments and accessories		1,969		840		1,555
Services		1,520		1,563		1,427
Total revenue	$	8,232	$	3,175	$	8,531

The Company recognizes sales by geographic area based on the country in which the customer is based. Operating lease revenue from Senhance System leasing is included as Systems revenues in the above table and was approximately $1.3 million, $0.7 million, and $0 million in the years ended December 31, 2021, 2020 and 2019, respectively.

Transaction price allocated to remaining performance obligations relates to amounts allocated to products and services for which the revenue has not yet been recognized. A significant portion of this amount relates to service obligations performed under the Company's system sales contracts that will be invoiced and recognized as revenue in future periods. Transaction price allocated to remaining performance obligations was approximately $3.0 million, $3.1 million, and $3.7 million as of December 31, 2021, 2020, and 2019, respectively. The amounts as of December 31, 2021 are expected to be recognized as revenue over one to five years.

The Company invoices its customers based on the billing schedules in its sales arrangements. Payments are generally due 30 to 60 days from the date of invoice. Contract assets for the periods presented primarily represent the difference between the revenue that was recognized based on the relative selling price of the related performance obligations and the contractual billing terms in the arrangements. Contract assets are included in accounts receivable and totaled $0.1 million and $0.1 million as of December 31, 2021 and 2020, respectively. Deferred revenue for the periods presented was primarily related to service obligations, for which the service fees are billed up-front, generally annually. The associated deferred revenue is generally recognized ratably over the service period. The Company did not have any significant impairment losses on its contract assets for the periods presented. Revenue recognized for the years ended December 31, 2021, 2020 and 2019 that was included in the deferred revenue balance at the beginning of each reporting period was $0.6 million, $0.6 million and $1.0 million, respectively.

In connection with assets recognized from the costs to obtain a contract with a customer, the Company determined that the sales incentive programs for its sales team do not meet the requirements to be capitalized as the Company does not expect to generate future economic benefits from the related revenue from the initial sales transaction and such costs are expensed as incurred.

Senhance System Leasing

The Company enters into lease arrangements with certain qualified customers. Revenue related to arrangements including lease elements are allocated to lease and non-lease elements based on their relative standalone selling prices. Lease elements generally include a Senhance System, while non-lease elements generally include instruments, accessories, and services. For some lease arrangements, the customers are provided with the right to purchase the leased Senhance System at some point during and/or at the end of the lease term. In some arrangements lease payments are based on the usage of the Senhance System.

In determining whether a transaction should be classified as a sales-type, operating, or direct financing lease, the Company considers the following terms at lease commencement: (1) whether title of the Senhance System transfers automatically or for a nominal fee by the end of the lease term, (2) whether the present value of the minimum lease payments equals or exceeds substantially all of the fair value of the leased Senhance System, (3) whether the lease term is for the major part of the remaining economic life of the leased System, (4) whether the lease grants the lessee an option to purchase the leased Senhance System that the lessee is reasonably certain to exercise, and (5) whether the underlying Senhance System is of such a specialized nature that it is expected to have no alternative use to the Company at the end of the lease term. All such arrangements through December 31, 2021 are classified as operating leases.

Revenue related to lease elements from operating lease arrangements is generally recognized on a straight-line basis over the lease term or based upon Senhance System usage and is presented as product revenue. Revenue related to lease elements from operating lease arrangements was approximately $1.3 million, $0.7 million, $0 million for the years ended December 31, 2021, 2020 and 2019, respectively.

Cost of Revenue

Cost of revenue consists of contract manufacturing, materials, labor and manufacturing overhead incurred internally to produce the products. Depreciation expense related to leased systems is included in the cost of revenue. Shipping and handling costs incurred by the Company are included in the cost of revenue.  We expense all inventory obsolescence provisions as cost of revenue.

Research and Development Costs

Research and development expenses primarily consist of engineering, product development and regulatory expenses, incurred in the design, development, testing and enhancement of our products. Research and development costs are expensed as incurred.

Stock-Based Compensation

The Company recognizes expenses for share-based awards exchanged for services rendered equal to the estimated fair value of these awards over the requisite service period. The Company recognizes as expense, the grant-date fair value of stock options and other stock-based compensation issued to employees and non-employee directors over the requisite service periods, which are typically the vesting periods. The Company uses the Black-Scholes-Merton model to estimate the fair value of stock options. The volatility assumption used in the Black-Scholes-Merton model is based on the Company’s historical volatility. The expected term of options granted has been determined based upon the simplified method, because the Company does not have sufficient historical information regarding its options to derive the expected term. Under this approach, the expected term is the mid-point between the weighted average of vesting period and the contractual term. The risk-free interest rate is based on U.S. Treasury rates whose term is consistent with the expected life of the stock options. The Company has not paid and does not anticipate paying cash dividends on its shares of common stock; therefore, the expected dividend yield is assumed to be zero. The Company estimates forfeitures based on its historical experience and adjust the estimated forfeiture rate based upon actual experience. For awards with performance conditions, we begin recognizing compensation expense when it becomes probable that the performance condition will be attained.

The fair value of restricted stock units is determined by the market price of the Company’s common stock on the date of grant.

The Company records as expense the fair value of stock-based compensation awards, including stock options and restricted stock units. Compensation expense for stock-based compensation was approximately $9.4 million, $7.9 million, and $11.5 million for the years ended December 31, 2021, 2020, and 2019 respectively.

Income Taxes

The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets or liabilities for the temporary differences between financial reporting and tax basis of the Company’s assets and liabilities, and for tax carryforwards at enacted statutory rates in effect for the years in which the asset or liability is expected to be realized. The effect on deferred taxes of a change in tax rates is recognized in income during the period that includes the enactment date. In addition, valuation allowances are established when necessary to reduce deferred tax assets and liabilities to the amounts expected to be realized. The Company has elected to account for global intangible low-taxed income (“GILTI”) as a period expense in the year the tax is incurred.

The Company recognizes the financial statement benefit of an income tax position only after determining that the relevant taxing authority would more likely than not sustain the position following audit. For tax positions meeting the more likely than not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes.

Tax regulations within each jurisdiction are subject to the interpretation of the related tax laws and regulations and require application of significant judgment. The Company is subject to U.S. federal and various state, local and foreign jurisdictions. Due to the Company’s net operating loss carryforwards, the Company may be subject to examination by authorities for all previously filed income tax returns.

Revision of Previously Disclosed Amounts

During the course of preparing the Company’s consolidated financial statements as of and for the year ended December 31 2021, the Company completed an Internal Revenue Code Section 382 and 383 analysis of its historical net operating loss and tax credit carryforward amounts. As a result, a portion of the prior year net operating loss and tax credit carryforwards were determined to be limited. See Note 11—Income Taxes, for further details. 

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources.

Segments

The Company operates in one business segment—the research, development and sale of medical device robotics to improve minimally invasive surgery. The Company’s chief operating decision maker (determined to be the Chief Executive Officer) does not manage any part of the Company separately, and the allocation of resources and assessment of performance are based on the Company’s consolidated operating results.

Approximately 77% and 27% of the Company’s total consolidated assets are located within the U.S. as of December 31, 2021 and 2020, respectively. The remaining assets are mostly located in Europe and are primarily related to the Company’s facility in Italy, and include intellectual property, other current assets, property and equipment, cash, accounts receivable, other long-term assets and inventory of $43.2 million and $56.8 million as of December 31, 2021 and 2020, respectively. Total assets outside of the United States amounted to 23% and 73% of total consolidated assets at December 31, 2021 and 2020, respectively. Long-lived assets in the U.S. were 63% and 11%, Switzerland were 22% and 41%, and Italy were 13% and 48%, as of December 31, 2021 and 2020, respectively.

The Company recognizes sales by geographic area based on the country in which the customer is based. For the years ended December 31, 2021, 2020 and 2019, 13%, 27% and 6%, respectively, of net revenue was generated in the United States; while 62%, 53% and 39%, respectively, was generated in Europe; and 25%, 20%, and 55%, respectively, was generated in Asia. For the year ended December 31, 2021, 47% of net revenue was generated in Germany, 22% was generated in Japan, and 13% was generated in the United States. For the year ended December 31, 2020, 28% of net revenue was generated in Germany, 27% was generated in the Untied States, 10% was generated in Japan, and 10% was generated in Taiwan. For the year ended December 31, 2019, 53% of net revenue was generated in Taiwan, and 23% was generated in Germany.

Impact of Recently Issued Accounting Standards

In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes, which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in ASC 740, Income Tax and also clarifies and amends existing guidance to improve consistent application. The Company adopted ASU 2019-12 effective January 1, 2021; the adoption did not result in a material impact on the Company's financial statements and related disclosures.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which is designed to provide financial statement users with more information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. When determining such expected credit losses, the guidance requires companies to apply a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. This guidance is effective on a modified retrospective basis for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The guidance is not expected to have a material impact on the Company's financial statements and related disclosures.

In August 2020, the FASB issued ASU 2020-06 Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (subtopic 815-40) guidance on the accounting for convertible debt instruments and contracts in an entity’s own equity. The guidance simplifies the accounting for convertible instruments by reducing the various accounting models that can require the instrument to be separated into a debt component and equity component or derivative component. Additionally, the guidance eliminated certain settlement conditions previously required to be able to classify a derivative in equity. The new guidance is effective on a modified or full retrospective basis for fiscal years beginning after December 15, 2021, including interim periods with those fiscal years. The Company is currently evaluating the impact on the consolidated financial statements upon adoption.

The Company has evaluated all other issued and unadopted ASUs and believes the adoption of these standards will not have a material impact on its consolidated statements of operations and comprehensive loss, balance sheets, or statements of cash flows.