The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. We base our estimates, in part, on historical experience that we believe to be reasonable under the circumstances. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the condensed consolidated financial statements in the period they are determined to be necessary.

Significant areas that require estimates include revenue recognition, intangible assets, business acquisition liabilities, allowance for doubtful accounts, stock-based compensation, reserves for excess and obsolete inventory, useful lives of assets, the outcome of litigation, recoverability of intangible assets and income taxes. We are subject to risks and uncertainties due to changes in the healthcare environment, regulatory oversight, competition, and legislation that may cause actual results to differ from estimated results.

Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration we expect to receive in exchange for those products or services. Sales and other taxes we collect concurrent with revenue-producing activities are excluded from revenue. For purposes of disclosure, we disaggregate our revenue into two categories, Musculoskeletal Solutions and Enabling Technologies. Our Musculoskeletal Solutions products consist primarily of the implantable devices, disposables, and unique instruments used in an expansive range of spine, orthopedic trauma, hip, knee and extremity procedures. The majority of contracts with our customers for Musculoskeletal Solutions products have a single performance obligation and revenue is recognized at a point in time. Our Enabling Technologies products are advanced robotics hardware systems and related technologies that are designed to enhance a surgeon’s capabilities and streamline surgical procedures by making them less invasive, more accurate, and more reproducible to improve patient care. The majority of contracts with our customers for Enabling Technologies products contain multiple performance obligations, including maintenance and support, and revenue is recognized as we fulfill each performance obligation. When contracts have multiple performance obligations, we allocate the contract’s transaction price to each performance obligation using our best estimate of the standalone selling price of each distinct good or service in the contract. Our policy is to classify shipping and handling costs billed to customers as sales and the related expenses as cost of goods sold.

Nature of Products and Services

A significant portion of our Musculoskeletal Solutions product revenue is generated from consigned inventory maintained at hospitals or with sales representatives. Revenue from the sale of consigned musculoskeletal products is recognized when we transfer control, which generally occurs at the time the product is used or implanted. For all other Musculoskeletal Solutions product transactions, we recognize revenue when we transfer title to the goods, provided there are no remaining performance obligations that can affect the customer’s final acceptance of the sale.

Revenue from the sale of Enabling Technologies products is generally recognized when control transfers to the customer which occurs at the time the product is shipped or delivered. Any revenue related to the provision of maintenance and support is recognized as we satisfy the performance obligation. We use an observable price to determine the stand-alone selling price for each separate performance obligation.

Contract Balances

Timing of revenue recognition may differ from the timing of invoicing to customers. We record a receivable when revenue is recognized prior to invoicing, or deferred revenue when revenue is recognized subsequent to invoicing.

Deferred revenue is comprised mainly of unearned revenue related to the sales of certain Enabling Technologies products, which includes maintenance and support services. Maintenance and support services are generally invoiced annually, at the beginning of each contract period, and revenue is recognized ratably over the maintenance period. For the three months ended March 31, 2021 and 2020, there was an immaterial amount of revenue recognized from previously deferred revenue.

The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents. Cash equivalents, which consist of money market accounts, commercial paper and corporate debt securities are stated at fair value.

Our marketable securities include municipal bonds, corporate debt securities, commercial paper, asset-backed securities, and securities of government, federal agency, and other sovereign obligations are classified as available-for-sale as of March 31, 2021 and December 31, 2020. Short-term and long-term marketable securities are recorded at fair value on our condensed consolidated balance sheets. Any changes in the fair value of our available-for-sale securities, that do not result in recognition or reversal of an allowance for credit loss or write-down, are recorded, net of taxes, as a component of accumulated other comprehensive income or loss on our condensed consolidated balance sheets. Premiums and discounts are recognized over the life of the related security as an adjustment to yield using the straight-line method. Realized gains or losses from the sale of marketable securities are determined on a specific identification basis. Realized gains and losses, interest income and the amortization/accretion of premiums/discounts are included in other income/(expense), net, on our condensed consolidated statements of operations and comprehensive income. Interest receivable is recorded in prepaid expenses and other current assets on our condensed consolidated balance sheets.

We invest in securities that meet or exceed standards as defined in our investment policy. Our policy also limits the amount of credit exposure to any one issue, issuer or type of security. We review our securities for other-than-temporary impairment at each reporting period. If an unrealized loss for any security is expected, the loss will be recognized on an allowance basis, consistent with ASC 326-30, in our condensed consolidated statement of operations and comprehensive income in the period the determination is made.

Assets and Liabilities That Are Measured at Fair Value on a Recurring Basis

Fair value is defined as the 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 the liability in an orderly transaction between market participants on the measurement date. Additionally, a fair value hierarchy was established that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets and liabilities and the lowest priority to unobservable inputs. The level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Our assets and liabilities measured at fair value on a recurring basis are classified and disclosed in one of the following three categories:

Level 1—quoted prices (unadjusted) in active markets for identical assets and liabilities;

Level 2—observable inputs other than quoted prices in active markets for identical assets and liabilities; and

Level 3—unobservable inputs in which there is little or no market data available, which require the reporting entity to use significant unobservable inputs or valuation techniques.

Assets and Liabilities That Are Measured at Fair Value on a Nonrecurring Basis

The purchase price of business acquisitions is primarily allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values on the acquisition date, with the excess recorded as goodwill. We utilize Level 3 inputs in the determination of the initial fair value.

Contingent consideration represents contingent milestone, performance and revenue-sharing payment obligations related to business acquisitions and is measured at fair value, based on significant inputs that are not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The valuation of contingent consideration uses assumptions we believe would be made by a market participant. We assess these assumptions on an ongoing basis as additional data impacting the assumptions is obtained. The fair value of contingent consideration recorded in business acquisition liabilities on our condensed consolidated balance sheets, and changes in the fair value of contingent consideration are recognized within acquisition related costs in the condensed consolidated statements of operations and comprehensive income. The fair value of contingent restricted stock unit (“RSU”) grants are recorded as additional paid-in capital in the consolidated balance sheet on the day of the grant due to the remote likelihood of forfeiture.

Inventories are stated at the lower of cost or net realizable value. Cost is determined on a first-in, first-out basis. The majority of our inventory is finished goods and we utilize both in-house manufacturing and third-party suppliers to produce our products. We periodically evaluate the carrying value of our inventories in relation to estimated forecasts of product demand, which takes into consideration the life cycle of product releases. When quantities on hand exceed estimated sales forecasts, we record a write-down for such excess inventories. Once inventory has been written down, it creates a new cost basis for inventory that is not subsequently written up.

Goodwill represents the excess of purchase price over the fair values of the identifiable assets acquired less the liabilities assumed in the acquisition of a business. Goodwill is tested for impairment at least annually or whenever events or circumstances indicate that a carrying amount may not be recoverable. Goodwill is tested for impairment at the reporting unit level by comparing the reporting unit’s carrying amount to the fair value of the reporting unit. Fair values are estimated using an income and discounted cash flow approach. We perform our annual impairment test of goodwill in the fourth quarter of each year. We consider qualitative indicators of the fair value of a reporting unit when it is unlikely that a reporting unit has impaired goodwill. During the three months ended March 31, 2021 and 2020, we did not record any impairment charges related to goodwill.

Intangible assets consist of purchased in-process research and development (“IPR&D”), developed technology, supplier network, patents, customer relationships, re-acquired rights, and non-compete agreements. Intangible assets with finite useful lives are amortized over the period of estimated benefit using the straight-line method and estimated useful lives ranging from one to sixteen years. Intangible assets are tested for impairment annually or whenever events or circumstances indicate that a carrying amount of an asset (asset group) may not be recoverable. If an impairment is indicated, we measure the amount of the impairment loss as the amount by which the carrying amount exceeds the fair value of the asset. Fair value is generally determined using a discounted future cash flow analysis. There were no impairments of finite-lived intangible assets during the three months ended March 31, 2021 or 2020.

IPR&D has an indefinite life and is not amortized until completion of the project at which time the IPR&D becomes an amortizable asset. If the related project is not completed in a timely manner, we may have an impairment related to the IPR&D, calculated as the excess of the asset’s carrying value over its fair value. There were no impairments of IPR&D during the three months ended March 31, 2021 or 2020.

The cost of employee and non-employee director awards is measured at the grant date fair value of the award and is recognized as expense over the requisite service period, which is generally the vesting period of the equity award. Compensation expense for awards includes the impact of forfeiture in the period when they occur.

We estimate the fair value of stock options utilizing the Black-Scholes option-pricing model. Inputs to the Black-Scholes model include our stock price, expected volatility, expected term, risk-free interest rate and expected dividends. Expected volatility is based on the historical volatility of the Company’s common stock over the most recent period commensurate with the estimated expected term of the Company’s stock options offering period which is derived from historical experience. The risk-free interest rate assumption is based on observed interest rates of U.S. Treasury securities appropriate for the expected terms of the stock options. The dividend yield assumption is based on the history and expectation of no dividend payouts. The fair value of restricted stock units is estimated using the closing price of the Company’s common stock on the date of grant.