Organization and Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The Company Tandem Diabetes Care, Inc. is a global insulin delivery and diabetes technology company focused on the design, development, and commercialization of technology solutions that reduce the burden of diabetes management. Tandem Diabetes Care, Inc. is incorporated in the state of Delaware. Unless the context requires otherwise, the terms the “Company” or “Tandem” refer to Tandem Diabetes Care, Inc., together with its wholly-owned subsidiaries. The Company’s strategy is to offer flexibility and choice in intelligent insulin delivery systems through an accessible portfolio of market-leading pumps, applications and insights. In support of this strategy, the Company’s pump platforms include t:slim X2 and Tandem Mobi (Mobi). Both pumps feature Control-IQ+ technology, which is the Company’s most advanced algorithm for managing insulin delivery, using information received from compatible continuous glucose monitoring (CGM) sensors. New software for the insulin pumps may be updated remotely by the individual users as new advancements become available. The insulin pumps are compatible with other complementary digital health offerings, such as the Company’s mobile application and cloud-based diabetes management applications. The Company’s insulin pumps are durable medical devices designed for multiple years of daily use. In addition, the Company sells disposable supplies used in conjunction with the pumps, which are replaced periodically. These supplies include cartridges for storing insulin, and infusion sets that contain a cannula and connect the pump to a user’s body to administer insulin.
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The Company has prepared the accompanying unaudited condensed consolidated financial statements in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and pursuant to the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying condensed consolidated financial statements include all adjustments, consisting only of normal and recurring adjustments, necessary for a fair presentation. Interim financial results are not necessarily indicative of results anticipated for the full year or any other period(s). These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 (Annual Report), from which the condensed consolidated balance sheet presented as of December 31, 2025 herein was derived. The condensed consolidated financial statements include the accounts of Tandem Diabetes Care, Inc. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. The functional currency of each of the Company’s foreign subsidiaries is its respective local currency. The Company translates the financial statements of its foreign subsidiaries into U.S. dollars using period-end exchange rates for assets and liabilities and average exchange rates for each period for revenue, costs and expenses. Translation-related adjustments are included in other comprehensive income (loss) in the condensed consolidated statements of operations, and in accumulated other comprehensive income (loss) in the stockholders’ equity section of the Company’s condensed consolidated balance sheets. Foreign exchange gains or losses resulting from balances denominated in a currency other than the functional currency are recognized in interest income and other income, net in the Company’s condensed consolidated statements of operations.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s condensed consolidated financial statements and accompanying notes as of the date of the condensed consolidated financial statements. Some of those judgments can be subjective and complex, and therefore, actual results could differ materially from those estimates under different assumptions or conditions.
Accounts Receivable	Accounts Receivable The Company grants credit to various customers in the ordinary course of business and is paid directly by customers who use its products, distributors and third-party insurance payors. The Company maintains an allowance for its current estimate of expected credit losses. Provisions for expected credit losses are estimated based on historical experience, assessment of specific customer-related risks, review of outstanding invoices, forecasts about the future, and various other assumptions and estimates that are believed to be reasonable under the circumstances, including the impact of broader macroeconomic conditions such as changes in credit risk, discretionary spending, and interest rates. Uncollectible accounts are written off against the allowance after appropriate collection efforts have been exhausted and when it is deemed that a balance is uncollectible.
Operating Lease Right-of-Use Assets and Liabilities	Operating Lease Right-of-Use Assets and Liabilities Operating lease right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized when the Company takes possession of the leased property (the Commencement Date) based on the present value of lease payments over the lease term. For lease agreements that contain lease and non-lease components, the Company accounts for both of those components as a single lease component. Rent expense on noncancelable leases containing known future scheduled rent increases is recorded on a straight-line basis over the term of the respective leases beginning on the Commencement Date. The difference between rent expense and rent paid is accounted for as a component of operating lease right-of-use assets on the Company’s condensed consolidated balance sheets. Landlord improvement allowances and other similar lease incentives are recorded as a reduction of the right-of-use lease assets, and are amortized on a straight-line basis as a reduction to operating lease costs.
Intangible Assets Subject to Amortization	Intangible Assets Subject to Amortization Finite-lived intangible assets are recorded at cost, net of accumulated amortization and, if applicable, impairment charges. Amortization of finite-lived intangible assets is recognized over their estimated useful lives using a straight-line or accelerated attribution method, depending on the economic benefit associated with the asset.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets, such as property and equipment, operating lease right-of-use assets, and acquired intangible assets subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined using unobservable (Level 3) inputs (see Note 5 “Fair Value Measurements”), including discounted cash flow models, future estimated sublease income, and third-party independent appraisals, as considered necessary. There is uncertainty in the projected undiscounted future cash flows used in the Company’s impairment review analysis, which requires the use of estimates and assumptions. If actual performance does not meet or exceed projected performance, or if the assumptions used in the model change in the future, the Company may be required to recognize additional impairment charges in future periods. The Company recognized the impairment of operating lease right-of-use assets in the first quarter of 2025 (see Note 6, “Leases”). There were no other impairments of long-lived assets, including acquired intangible assets, during the three and six months ended June 30, 2026 and 2025.
Equity Method Investments	Equity Method Investment The Company uses the equity method to account for investments in companies if it owns more than 20% of the investee company’s outstanding equity or the investment provides the Company with the ability to exercise significant influence but not control over the operating and financial policies of the investee. The Company assesses whether it has significant influence by considering various factors, including the nature and magnitude of the investment, voting rights held, and participation in the governance of the investee, if any. The Company may also consider additional relevant factors, such as the presence of other business relationships. The Company held an equity method investment in CeQur SA (CeQur), a privately held company, of $132.3 million and $60.4 million as of June 30, 2026 and December 31, 2025, respectively. On May 22, 2026, the Company made an additional investment in CeQur of CHF 64.0 million ($81.4 million USD), remaining at an ownership level of less than 50%. The Company continues to account for the investment under the equity method. The additional investment was recorded as an increase to the carrying value of the existing equity method investment. In connection with the additional investment, the Company obtained, for an immaterial amount, the option to acquire the remainder of CeQur’s shares no earlier than 2028 at its sole discretion. In the event the option is exercised, the price to be paid will be calculated using a predetermined market-based formula. The Company recorded this call option in other long-term assets on the condensed consolidated balance sheets. The call option does not meet the criteria for derivative accounting. Equity method investments are reviewed for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. No impairment charges were recognized for the equity method investment during the three and six months ended June 30, 2026. The Company’s condensed consolidated net loss included its proportionate share of the net loss of its equity method investee, which was $5.6 million and $9.5 million for the three and six months ended June 30, 2026, respectively, and $3.4 million and $6.9 million for the three and six months ended June 30, 2025, respectively.
Revenue Recognition / Variable Consideration	Revenue Recognition Revenue is generated primarily from sales of insulin pumps, single-use insulin cartridges and infusion sets to individual customers with third-party insurance coverage and through a network of distributors that resell the products to insulin-dependent diabetes customers. The Company recognizes revenue when it transfers control of the promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services, net of estimated rebates, prompt payment discounts, and a provision for product returns. Revenue Recognition for Arrangements with Multiple Performance Obligations The Company considers the individual deliverables in its product offerings to be separate performance obligations. The transaction price is the net consideration to which the Company expects to be entitled, determined from either the stated value in contractual arrangements or the estimated cash to be collected in non-contracted arrangements. The transaction price also includes an estimate of variable consideration at the time of sale. Variable consideration includes, but is not limited to: rebates, prompt payment discounts, and a provision for product returns. These amounts are recorded as a reduction of accounts receivable when no payment is required from the Company and as a liability when a payment is required. The Company recognizes consideration based on when the performance obligation is satisfied, considering whether or not this occurs at a point in time or over time. Generally, insulin pumps, cartridges, infusion sets, and accessories are deemed performance obligations that are satisfied at a point in time when the customer obtains control of the promised good, which is typically upon shipment or delivery as title transfers. Certain complementary products, such as the Company’s data management and software update platforms, are considered distinct performance obligations that are satisfied over time, as access and support for these products is provided throughout the typical four-year warranty period of the insulin pumps. Accordingly, revenue related to these complementary products is deferred and recognized over the period of the performance obligation according to the agreement. The Company allocates the transaction price to each individual performance obligation based on the standalone selling price. For the pay-as-you-go reimbursement model, the Company allocates a portion of the transaction price associated with the customer’s initial supply order to the pump based on its relative standalone selling price. When standalone selling prices are not directly observable, the Company estimates such amounts using an expected cost plus a margin approach and allocates any residual consideration to the remaining performance obligations, as appropriate. Variable Consideration The amount of variable consideration that is included in the transaction price is included in revenue only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. The Company is subject to certain rebates on pricing programs with managed care organizations, including pharmacy benefit managers and governmental or third-party commercial payors. The terms of these programs may vary depending on the customer and contractual arrangements. The Company estimates provisions for rebates based on contractual arrangements, estimates of products sold subject to rebate, known market events or trends, and channel inventory data. Sales rebates are recorded as a reduction of revenue and are included within other current or long-term liabilities on the consolidated balance sheets, depending on the anticipated settlement period of the rebate. Actual rebate payments may differ from estimated amounts recorded in the accompanying consolidated financial statements.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company records the fair value of derivative instruments as either current assets or current liabilities on the condensed consolidated balance sheets. Changes in the fair value of derivative instruments are recorded each period in current earnings or other comprehensive income (loss), depending on whether a derivative instrument is designated as part of a hedging transaction. For a derivative to qualify as a hedge at inception and throughout the hedged period, the Company formally documents the nature and relationships between the hedging instrument and hedged item. For derivatives formally designated as hedges, the Company assesses both at inception and quarterly thereafter, whether the hedging derivatives are highly effective in offsetting changes in either the fair value or cash flows of the hedged item. Gains or losses on cash flow hedges are reclassified from other comprehensive income (loss) to earnings when the hedged transaction occurs and affects consolidated results. Gains or losses on fair value hedges are recognized in earnings immediately and offset against changes in the fair value of the underlying hedged asset, liability, or firm commitment. If the Company determines that a forecasted transaction is no longer probable or no longer qualifies for hedge accounting treatment, the Company discontinues hedge accounting and any related unrealized gain or loss on the derivative instrument is recognized in current earnings.
Warranty Reserve	Warranty Reserve The Company generally provides a four-year warranty on its insulin pumps to end-user customers and may replace any pumps that do not function as intended in accordance with the product specifications within the warranty period. In addition, the Company offers a six-month warranty on single-use insulin cartridges and infusion sets. Estimated warranty costs are recorded at the time of shipment, and the Company reevaluates the estimate of the warranty reserve obligation at each reporting period. Warranty costs are primarily estimated based on expected replacement rates using historical experience and the expected product replacement cost. Returned insulin pumps may be refurbished and redeployed. Experience has shown that initial data for any new pump version or pump platform may be insufficient. Therefore, the Company relies on long-term historical replacement data from existing platforms until sufficient data is available. As actual experience accumulates, the Company adjusts its warranty reserve estimate accordingly. In addition, the availability of replacement data may differ by country due to local compliance and privacy regulations, which may require the Company to estimate its warranty liability using available information or data from similar markets. The Company may further adjust the warranty reserve when appropriate, considering revised expectations of product performance based on enhanced hardware, or new features and capabilities that may become available through Tandem Device Updater, a tool that allows Tandem pump users to update their pump software from a personal computer. Warranty expense is recorded as a component of cost of sales in the consolidated statements of operations.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation cost is measured at the grant date based on the estimated fair value of the award, and the portion that is ultimately expected to vest is recognized as compensation expense over the requisite service period on a straight-line basis. The Company estimates the fair value of employee purchase rights under the Company’s Employee Stock Purchase Plan (ESPP) using the Black-Scholes option pricing model on the date of grant. The Black-Scholes option pricing model requires the use of assumptions, including stock price volatility, expected term, dividend yield and risk-free interest rate. The fair value of restricted stock unit (RSU) awards issued under the Company’s stock incentive plans that vest solely based on service, is estimated based on the fair market value of the underlying stock on the date of grant. The fair value of RSU awards that vest based upon predefined Company performance metrics and the awardee’s continuing service through the measurement date is generally estimated based on the fair market value of the underlying stock on the grant date and the estimated probability of achieving the applicable performance conditions. The Company reassesses the probability of achieving such performance conditions each reporting period, and any resulting adjustment to compensation expense is recognized in the period of change. For certain performance-based RSUs with market-based criteria, the Company uses a Monte Carlo methodology to estimate the fair value at the date of grant. With respect to RSU awards with a market condition, the Company recognizes compensation expense ratably over the requisite service period under an award based on the fair market value of the award at the time of grant, regardless of whether the market condition is satisfied. Previously recognized compensation cost would be reversed only if the employee terminated employment before completing the requisite service period.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period, without consideration for common share equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding, including all potentially dilutive common share equivalents. Dilutive common share equivalents are comprised of stock options and unvested RSUs outstanding under the Company’s stock incentive plans, potential awards to be granted pursuant to the ESPP, and common stock warrants, each calculated using the treasury stock method, and shares issuable upon conversion of the Company’s convertible senior notes calculated using the if-converted method.
Recently Adopted Accounting Pronouncements and Accounting Pronouncements Issued and Not Yet Adopted	Recently Adopted Accounting Pronouncements In September 2025, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2025-06 Intangibles–Goodwill and Other–Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software (ASU 2025-06), which modernizes the accounting guidance for internal-use software, including website development costs. The amendments eliminate the consideration of software development stages and introduce a new capitalization threshold based on the entity’s commitment to fund the project and the probability of completion. The Company early adopted ASU 2025-06 effective January 1, 2026 using the prospective method. The adoption of ASU 2025-06 did not have a material impact on the Company’s condensed consolidated financial statements. Accounting Pronouncements Issued and Not Yet Adopted In November 2024, the FASB issued ASU 2024-03 Income Statement–Reporting Comprehensive Income–Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (ASU 2024-03), and in January 2025, the FASB issued Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date (ASU 2025-01). ASU 2024-03 requires entities to disclose information about purchases of inventory, employee compensation, and intangible asset amortization in each income statement line item that contains those expenses. ASU 2024-03, as clarified by ASU 2025-01, is effective for the annual reporting period beginning after December 15, 2026 and interim reporting periods within the annual reporting period beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating ASU 2024-03, as clarified by ASU 2025-01, to determine the impact it may have on its consolidated financial statements. In November 2025, the FASB issued ASU 2025-09 Derivatives and Hedging (Topic 815): Hedge Accounting Improvements (ASU 2025-09). This update is intended to better align hedge accounting with entities’ risk management strategies and simplify application. Key provisions include allowing grouping of forecasted transactions with similar risk exposure, introducing a model for hedging variable-rate debt instruments that permit rate selection, permitting component hedging for certain nonfinancial forecasted transactions, clarifying treatment of certain compound derivatives, and restoring operability for specific dual hedge strategies. ASU 2025-09 is effective for fiscal years beginning after December 15, 2026, including interim periods, with early adoption permitted. The Company is currently evaluating ASU 2025-09 to determine the impact it may have on its consolidated financial statements. In December 2025, the FASB issued ASU 2025-11 Interim Reporting (Topic 270): Narrow-Scope Improvements (ASU 2025-11), which clarifies and improves the guidance for interim financial reporting. The amendments introduce a disclosure principle requiring entities to disclose events since the end of the previous annual reporting period that materially affect the entity, consolidate a comprehensive list of interim disclosure requirements within ASC 270, and provide guidance on the form and content of condensed interim financial statements. ASU 2025-11 will be effective for interim reporting periods in fiscal years beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating ASU 2025-11 to determine the impact it may have on its consolidated financial statements.
Fair Value Measurements	The Company performs fair value measurements in accordance with U.S. GAAP. Fair value is defined as the price that would be received from the sale of an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. To measure fair value of assets and liabilities, the Company uses the following fair value hierarchy based on three levels of inputs: Level 1 — observable inputs, such as quoted prices in active markets for identical assets or liabilities; Level 2 — significant other observable inputs that are observable either directly or indirectly; and Level 3 — significant unobservable inputs for which there are little or no market data, which require the Company to develop its own assumptions. The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued expenses, and employee-related liabilities are reasonable estimates of their fair values because of the short-term nature of these assets and liabilities. Short-term investments are carried at fair value.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker (CODM) in making decisions regarding resource allocation and assessing performance. The Company is organized based on its current product portfolio, which consists primarily of insulin pumps, single-use insulin cartridges, and infusion sets for the storage and delivery of insulin. The Company views its operations and manages its business as one reporting segment because key operating decisions and resource allocations are made by the CODM using consolidated financial data. Accordingly, the Company is organized as a single operating segment and therefore a single reportable segment: Insulin Pumps and Supplies. The Company’s CODM is the Chief Executive Officer (CEO), who evaluates segment performance based on segment net income (loss) on a consolidated basis. Segment net income (loss) was consistent with the net loss amounts reported in the Company’s condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2026 and 2025. There were no significant segment expenses that are regularly provided to the CODM other than those reported in the Company’s condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2026 and 2025. The Company’s CODM is provided segment assets information on a consolidated basis for the evaluation of Company performance. Total segment assets were consistent with total assets reported in the Company’s consolidated balance sheets for June 30, 2026 and December 31, 2025.

Organization and Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Tandem Diabetes Care, Inc. is a global insulin delivery and diabetes technology company focused on the design, development, and commercialization of technology solutions that reduce the burden of diabetes management. Tandem Diabetes Care, Inc. is incorporated in the state of Delaware. Unless the context requires otherwise, the terms the “Company” or “Tandem” refer to Tandem Diabetes Care, Inc., together with its wholly-owned subsidiaries.

The Company’s strategy is to offer flexibility and choice in intelligent insulin delivery systems through an accessible portfolio of market-leading pumps, applications and insights. In support of this strategy, the Company’s pump platforms include t:slim X2 and Tandem Mobi (Mobi). Both pumps feature Control-IQ+ technology, which is the Company’s most advanced algorithm for managing insulin delivery, using information received from compatible continuous glucose monitoring (CGM) sensors. New software for the insulin pumps may be updated remotely by the individual users as new advancements become available. The insulin pumps are compatible with other complementary digital health offerings, such as the Company’s mobile application and cloud-based diabetes management applications. The Company’s insulin pumps are durable medical devices designed for multiple years of daily use. In addition, the Company sells disposable supplies used in conjunction with the pumps, which are replaced periodically. These supplies include cartridges for storing insulin, and infusion sets that contain a cannula and connect the pump to a user’s body to administer insulin.

Basis of Presentation and Principles of Consolidation

The Company has prepared the accompanying unaudited condensed consolidated financial statements in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and pursuant to the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying condensed consolidated financial statements include all adjustments, consisting only of normal and recurring adjustments, necessary for a fair presentation.

Interim financial results are not necessarily indicative of results anticipated for the full year or any other period(s). These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 (Annual Report), from which the condensed consolidated balance sheet presented as of December 31, 2025 herein was derived. The condensed consolidated financial statements include the accounts of Tandem Diabetes Care, Inc. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.

The functional currency of each of the Company’s foreign subsidiaries is its respective local currency. The Company translates the financial statements of its foreign subsidiaries into U.S. dollars using period-end exchange rates for assets and liabilities and average exchange rates for each period for revenue, costs and expenses. Translation-related adjustments are included in other comprehensive income (loss) in the condensed consolidated statements of operations, and in accumulated other comprehensive income (loss) in the stockholders’ equity section of the Company’s condensed consolidated balance sheets. Foreign exchange gains or losses resulting from balances denominated in a currency other than the functional currency are recognized in interest income and other income, net in the Company’s condensed consolidated statements of operations.

Use of Estimates

The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s condensed consolidated financial statements and accompanying notes as of the date of the condensed consolidated financial statements. Some of those judgments can be subjective and complex, and therefore, actual results could differ materially from those estimates under different assumptions or conditions.

Accounts Receivable

The Company grants credit to various customers in the ordinary course of business and is paid directly by customers who use its products, distributors and third-party insurance payors. The Company maintains an allowance for its current estimate of expected credit losses. Provisions for expected credit losses are estimated based on historical experience, assessment of specific customer-related risks, review of outstanding invoices, forecasts about the future, and various other assumptions and estimates that are believed to be reasonable under the circumstances, including the impact of broader macroeconomic conditions such as changes in credit risk, discretionary spending, and interest rates. Uncollectible accounts are written off against the allowance after appropriate collection efforts have been exhausted and when it is deemed that a balance is uncollectible.

Operating Lease Right-of-Use Assets and Liabilities

Operating lease right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized when the Company takes possession of the leased property (the Commencement Date) based on the present value of lease payments over the lease term. For lease agreements that contain lease and non-lease components, the Company accounts for both of those components as a single lease component. Rent expense on noncancelable leases containing known future scheduled rent increases is recorded on a straight-line basis over the term of the respective leases beginning on the Commencement Date. The difference between rent expense and rent paid is accounted for as a component of operating lease right-of-use assets on the Company’s condensed consolidated balance sheets. Landlord improvement allowances and other similar lease incentives are recorded as a reduction of the right-of-use lease assets, and are amortized on a straight-line basis as a reduction to operating lease costs.

Intangible Assets Subject to Amortization

Finite-lived intangible assets are recorded at cost, net of accumulated amortization and, if applicable, impairment charges. Amortization of finite-lived intangible assets is recognized over their estimated useful lives using a straight-line or accelerated attribution method, depending on the economic benefit associated with the asset.

Impairment of Long-Lived Assets

Long-lived assets, such as property and equipment, operating lease right-of-use assets, and acquired intangible assets subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined using unobservable (Level 3) inputs (see Note 5 “Fair Value Measurements”), including discounted cash flow models, future estimated sublease income, and third-party independent appraisals, as considered necessary. There is uncertainty in the projected undiscounted future cash flows used in the Company’s impairment review analysis, which requires the use of estimates and assumptions. If actual performance does not meet or exceed projected performance, or if the assumptions used in the model change in the future, the Company may be required to recognize additional impairment charges in future periods. The Company recognized the impairment of operating lease right-of-use assets in the first quarter of 2025 (see Note 6, “Leases”). There were no other impairments of long-lived assets, including acquired intangible assets, during the three and six months ended June 30, 2026 and 2025.

Equity Method Investments

Equity Method Investment

The Company uses the equity method to account for investments in companies if it owns more than 20% of the investee company’s outstanding equity or the investment provides the Company with the ability to exercise significant influence but not control over the operating and financial policies of the investee. The Company assesses whether it has significant influence by considering various factors, including the nature and magnitude of the investment, voting rights held, and participation in the governance of the investee, if any. The Company may also consider additional relevant factors, such as the presence of other business relationships.

The Company held an equity method investment in CeQur SA (CeQur), a privately held company, of $132.3 million and $60.4 million as of June 30, 2026 and December 31, 2025, respectively. On May 22, 2026, the Company made an additional investment in CeQur of CHF 64.0 million ($81.4 million USD), remaining at an ownership level of less than 50%. The Company continues to account for the investment under the equity method. The additional investment was recorded as an increase to the carrying value of the existing equity method investment. In connection with the additional investment, the Company obtained, for an immaterial amount, the option to acquire the remainder of CeQur’s shares no earlier than 2028 at its sole discretion. In the event the option is exercised, the price to be paid will be calculated using a predetermined market-based formula. The Company recorded this call option in other long-term assets on the condensed consolidated balance sheets. The call option does not meet the criteria for derivative accounting.

Equity method investments are reviewed for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. No impairment charges were recognized for the equity method investment during the three and six months ended June 30, 2026.

The Company’s condensed consolidated net loss included its proportionate share of the net loss of its equity method investee, which was $5.6 million and $9.5 million for the three and six months ended June 30, 2026, respectively, and $3.4 million and $6.9 million for the three and six months ended June 30, 2025, respectively.

Revenue Recognition / Variable Consideration

Revenue Recognition

Revenue is generated primarily from sales of insulin pumps, single-use insulin cartridges and infusion sets to individual customers with third-party insurance coverage and through a network of distributors that resell the products to insulin-dependent diabetes customers. The Company recognizes revenue when it transfers control of the promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services, net of estimated rebates, prompt payment discounts, and a provision for product returns.

Revenue Recognition for Arrangements with Multiple Performance Obligations

The Company considers the individual deliverables in its product offerings to be separate performance obligations.

The transaction price is the net consideration to which the Company expects to be entitled, determined from either the stated value in contractual arrangements or the estimated cash to be collected in non-contracted arrangements. The transaction price also includes an estimate of variable consideration at the time of sale. Variable consideration includes, but is not limited to: rebates, prompt payment discounts, and a provision for product returns. These amounts are recorded as a reduction of accounts receivable when no payment is required from the Company and as a liability when a payment is required.

The Company recognizes consideration based on when the performance obligation is satisfied, considering whether or not this occurs at a point in time or over time. Generally, insulin pumps, cartridges, infusion sets, and accessories are deemed performance obligations that are satisfied at a point in time when the customer obtains control of the promised good, which is typically upon shipment or delivery as title transfers. Certain complementary products, such as the Company’s data management and software update platforms, are considered distinct performance obligations that are satisfied over time, as access and support for these products is provided throughout the typical four-year warranty period of the insulin pumps. Accordingly, revenue related to these complementary products is deferred and recognized over the period of the performance obligation according to the agreement.

The Company allocates the transaction price to each individual performance obligation based on the standalone selling price. For the pay-as-you-go reimbursement model, the Company allocates a portion of the transaction price associated with the customer’s initial supply order to the pump based on its relative standalone selling price. When standalone selling prices are not directly observable, the Company estimates such amounts using an expected cost plus a margin approach and allocates any residual consideration to the remaining performance obligations, as appropriate.

Variable Consideration

The amount of variable consideration that is included in the transaction price is included in revenue only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. The Company is subject to certain rebates on pricing programs with managed care organizations, including pharmacy benefit managers and governmental or third-party commercial payors. The terms of these programs may vary depending on the customer and contractual arrangements. The Company estimates provisions for rebates based on contractual arrangements, estimates of products sold subject to rebate, known market events or trends, and channel inventory data. Sales rebates are recorded as a reduction of revenue and are included within other current or long-term liabilities on the consolidated balance sheets, depending on the anticipated settlement period of the rebate. Actual rebate payments may differ from estimated amounts recorded in the accompanying consolidated financial statements.

Derivative Instruments and Hedging Activities

The Company records the fair value of derivative instruments as either current assets or current liabilities on the condensed consolidated balance sheets. Changes in the fair value of derivative instruments are recorded each period in current earnings or other comprehensive income (loss), depending on whether a derivative instrument is designated as part of a hedging transaction. For a derivative to qualify as a hedge at inception and throughout the hedged period, the Company formally documents the nature and relationships between the hedging instrument and hedged item.

For derivatives formally designated as hedges, the Company assesses both at inception and quarterly thereafter, whether the hedging derivatives are highly effective in offsetting changes in either the fair value or cash flows of the hedged item.

Gains or losses on cash flow hedges are reclassified from other comprehensive income (loss) to earnings when the hedged transaction occurs and affects consolidated results. Gains or losses on fair value hedges are recognized in earnings immediately and offset against changes in the fair value of the underlying hedged asset, liability, or firm commitment. If the Company determines that a forecasted transaction is no longer probable or no longer qualifies for hedge accounting treatment, the Company discontinues hedge accounting and any related unrealized gain or loss on the derivative instrument is recognized in current earnings.

Warranty Reserve

The Company generally provides a four-year warranty on its insulin pumps to end-user customers and may replace any pumps that do not function as intended in accordance with the product specifications within the warranty period. In addition, the Company offers a six-month warranty on single-use insulin cartridges and infusion sets. Estimated warranty costs are recorded at the time of shipment, and the Company reevaluates the estimate of the warranty reserve obligation at each reporting period. Warranty costs are primarily estimated based on expected replacement rates using historical experience and the expected product replacement cost. Returned insulin pumps may be refurbished and redeployed.

Experience has shown that initial data for any new pump version or pump platform may be insufficient. Therefore, the Company relies on long-term historical replacement data from existing platforms until sufficient data is available. As actual experience accumulates, the Company adjusts its warranty reserve estimate accordingly. In addition, the availability of replacement data may differ by country due to local compliance and privacy regulations, which may require the Company to estimate its warranty liability using available information or data from similar markets. The Company may further adjust the warranty reserve when appropriate, considering revised expectations of product performance based on enhanced hardware, or new features and capabilities that may become available through Tandem Device Updater, a tool that allows Tandem pump users to update their pump software from a personal computer. Warranty expense is recorded as a component of cost of sales in the consolidated statements of operations.

Stock-Based Compensation

Stock-based compensation cost is measured at the grant date based on the estimated fair value of the award, and the portion that is ultimately expected to vest is recognized as compensation expense over the requisite service period on a straight-line basis.

The Company estimates the fair value of employee purchase rights under the Company’s Employee Stock Purchase Plan (ESPP) using the Black-Scholes option pricing model on the date of grant. The Black-Scholes option pricing model requires the use of assumptions, including stock price volatility, expected term, dividend yield and risk-free interest rate.

The fair value of restricted stock unit (RSU) awards issued under the Company’s stock incentive plans that vest solely based on service, is estimated based on the fair market value of the underlying stock on the date of grant. The fair value of RSU awards that vest based upon predefined Company performance metrics and the awardee’s continuing service through the measurement date is generally estimated based on the fair market value of the underlying stock on the grant date and the estimated probability of achieving the applicable performance conditions. The Company reassesses the probability of achieving such performance conditions each reporting period, and any resulting adjustment to compensation expense is recognized in the period of change. For certain performance-based RSUs with market-based criteria, the Company uses a Monte Carlo methodology to estimate the fair value at the date of grant. With respect to RSU awards with a market condition, the Company recognizes compensation expense ratably over the requisite service period under an award based on the fair market value of the award at the time of grant, regardless of whether the market condition is satisfied. Previously recognized compensation cost would be reversed only if the employee terminated employment before completing the requisite service period.

Net Loss Per Share

Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period, without consideration for common share equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding, including all potentially dilutive common share equivalents. Dilutive common share equivalents are comprised of stock options and unvested RSUs outstanding under the Company’s stock incentive plans, potential awards to be granted pursuant to the ESPP, and common stock warrants, each calculated using the treasury stock method, and shares issuable upon conversion of the Company’s convertible senior notes calculated using the if-converted method.

Recently Adopted Accounting Pronouncements and Accounting Pronouncements Issued and Not Yet Adopted

Recently Adopted Accounting Pronouncements

In September 2025, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2025-06 Intangibles–Goodwill and Other–Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software (ASU 2025-06), which modernizes the accounting guidance for internal-use software, including website development costs. The amendments eliminate the consideration of software development stages and introduce a new capitalization threshold based on the entity’s commitment to fund the project and the probability of completion. The Company early adopted ASU 2025-06 effective January 1, 2026 using the prospective method. The adoption of ASU 2025-06 did not have a material impact on the Company’s condensed consolidated financial statements.

Accounting Pronouncements Issued and Not Yet Adopted

In November 2024, the FASB issued ASU 2024-03 Income Statement–Reporting Comprehensive Income–Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (ASU 2024-03), and in January 2025, the FASB issued Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date (ASU 2025-01). ASU 2024-03 requires entities to disclose information about purchases of inventory, employee compensation, and intangible asset amortization in each income statement line item that contains those expenses. ASU 2024-03, as clarified by ASU 2025-01, is effective for the annual reporting period beginning after December 15, 2026 and interim reporting periods within the annual reporting period beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating ASU 2024-03, as clarified by ASU 2025-01, to determine the impact it may have on its consolidated financial statements.

In November 2025, the FASB issued ASU 2025-09 Derivatives and Hedging (Topic 815): Hedge Accounting Improvements (ASU 2025-09). This update is intended to better align hedge accounting with entities’ risk management strategies and simplify application. Key provisions include allowing grouping of forecasted transactions with similar risk exposure, introducing a model for hedging variable-rate debt instruments that permit rate selection, permitting component hedging for certain nonfinancial forecasted transactions, clarifying treatment of certain compound derivatives, and restoring operability for specific dual hedge strategies. ASU 2025-09 is effective for fiscal years beginning after December 15, 2026, including interim periods, with early adoption permitted. The Company is currently evaluating ASU 2025-09 to determine the impact it may have on its consolidated financial statements.

In December 2025, the FASB issued ASU 2025-11 Interim Reporting (Topic 270): Narrow-Scope Improvements (ASU 2025-11), which clarifies and improves the guidance for interim financial reporting. The amendments introduce a disclosure principle requiring entities to disclose events since the end of the previous annual reporting period that materially affect the entity, consolidate a comprehensive list of interim disclosure requirements within ASC 270, and provide guidance on the form and content of condensed interim financial statements. ASU 2025-11 will be effective for interim reporting periods in fiscal years beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating ASU 2025-11 to determine the impact it may have on its consolidated financial statements.

Fair Value Measurements

The Company performs fair value measurements in accordance with U.S. GAAP. Fair value is defined as the price that would be received from the sale of an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. To measure fair value of assets and liabilities, the Company uses the following fair value hierarchy based on three levels of inputs:

Level 1 — observable inputs, such as quoted prices in active markets for identical assets or liabilities;

Level 2 — significant other observable inputs that are observable either directly or indirectly; and

Level 3 — significant unobservable inputs for which there are little or no market data, which require the Company to develop its own assumptions.

The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued expenses, and employee-related liabilities are reasonable estimates of their fair values because of the short-term nature of these assets and liabilities. Short-term investments are carried at fair value.

Segment Reporting

Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker (CODM) in making decisions regarding resource allocation and assessing performance. The Company is organized based on its current product portfolio, which consists primarily of insulin pumps, single-use insulin cartridges, and infusion sets for the storage and delivery of insulin. The Company views its operations and manages its business as one reporting segment because key operating decisions and resource allocations are made by the CODM using consolidated financial data. Accordingly, the Company is organized as a single operating segment and therefore a single reportable segment: Insulin Pumps and Supplies.

The Company’s CODM is the Chief Executive Officer (CEO), who evaluates segment performance based on segment net income (loss) on a consolidated basis. Segment net income (loss) was consistent with the net loss amounts reported in the Company’s condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2026 and 2025. There were no significant segment expenses that are regularly provided to the CODM other than those reported in the Company’s condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2026 and 2025.

The Company’s CODM is provided segment assets information on a consolidated basis for the evaluation of Company performance. Total segment assets were consistent with total assets reported in the Company’s consolidated balance sheets for June 30, 2026 and December 31, 2025.