CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This document, including the following Management’s Discussion and Analysis of Financial Condition and Results of Operations, contains forward-looking statements that are not purely historical regarding DexCom's or its management's intentions, beliefs, expectations and strategies for the future. These forward-looking statements fall within the meaning of the federal securities laws that relate to future events or our future financial performance. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “intend,” “potential” or “continue” or the negative of these terms or other comparable terminology. Forward-looking statements are made as of the date of this report, deal with future events, are subject to various risks and uncertainties, and actual results could differ materially from those anticipated in those forward looking statements. The risks and uncertainties that could cause actual results to differ materially are more fully described under “Risk Factors” and elsewhere in this report and in our other reports filed with the SEC. We assume no obligation to update any of the forward-looking statements after the date of this report or to conform these forward-looking statements to actual results.

Overview

We are a medical device company primarily focused on the design, development and commercialization of continuous glucose monitoring (“CGM”) systems for ambulatory use by people with diabetes and by healthcare providers in the hospital for the treatment of people with and without diabetes. Unless the context requires otherwise, the terms “we,” “us,” “our,” the “company,” or “DexCom” refer to DexCom, Inc. and its subsidiaries.

Background

From inception to 2006, we devoted substantially all of our resources to start-up activities, raising capital and research and development, including product design, testing, manufacturing and clinical trials. Since 2006, we have devoted considerable resources to the commercialization of our ambulatory continuous glucose monitoring systems, including the G4 PLATINUM and G5 Mobile, as well as the continued research and clinical development of our technology platform.

The International Diabetes Federation (“IDF”) estimates that in 2015, 415 million people around the world had diabetes, and the Centers for Disease Control (“CDC”) estimates that in 2012, diabetes affected 29.1 million people in the United States, of which 8.1 million were undiagnosed. IDF estimates that by 2040, the worldwide incidence of people suffering from diabetes will reach 642 million. According to the CDC 's National Vital Statistics Reports for 2010, diabetes was the seventh leading cause of death by disease in the United States. According to the Congressional Diabetes Caucus, diabetes is the leading cause of kidney failure, adult-onset blindness, lower-limb amputations, and significant cause of heart disease and stroke, high blood pressure and nerve damage. According to the IDF , there were an estimated 5 million deaths attributable to diabetes globally in 2015 between the ages of 20 and 79 years. The American Diabetes Association (“ADA”) Fast Facts, revised in July 2014, states that diabetes is the primary cause of death for more than 69,000 Americans each year, and contributes to the death of more than 234,000 Americans annually. According to an article published in The New England Journal of Medicine in November 2014, excess mortality for people with diabetes with ages of less than 30 years is largely explained by acute complications of diabetes.

According to the CDC 2011 National Diabetes Fact Sheet, in the United States, another individual is diagnosed with diabetes every 17 seconds. As reported by the Congressional Diabetes Caucus website, 1.9 million people will be diagnosed with diabetes this year, approximately 5,082 people per day. In 2012 alone there were about 1.7 million people 20 years or older diagnosed. In addition to those newly diagnosed, the Congressional Diabetes Caucus website reports that every 24 hours there are: 238 amputations in people with diabetes, 120 people who enter end-stage kidney disease programs, and 48 people who go blind.

According to the ADA , one in every five healthcare dollars was spent on treating diabetes in 2012, and the direct medical costs and indirect expenditures attributable to diabetes in the United States were an estimated $245 billion, an increase of $71 billion, or approximately 41%, since 2007. Of the $245 billion in overall expenses, the ADA estimated that approximately $176 billion were direct costs associated with diabetes care, chronic complications and excess general medical costs, and $69 billion were indirect medical costs. The ADA also found that average medical expenditures among people with diagnosed diabetes were 2.3 times higher than for people without diabetes in 2012. According to the IDF , expenditures attributable to diabetes were an estimated $673 to $1,197 billion globally in 2015. The IDF estimates that expenditures attributable to diabetes will grow to a range of $802 to $1,452 billion globally by 2040.

We believe continuous glucose monitoring has the potential to enable more people with diabetes to achieve and sustain tight glycemic control. The Diabetes Control and Complications Trial demonstrated that improving blood glucose control lowers the risk of developing diabetes-related complications by up to 50%. The study also demonstrated that people with Type 1 diabetes achieved sustained benefits with intensive management. Yet, according to an article published in the Journal of the American Medical Association in 2004, less than 50% of diabetes patients were meeting ADA standards for glucose control (A1c), and only 37% of people with diabetes were achieving their glycemic targets. According to an article published in The New England Journal of Medicine in November 2014, in two national registries, only 13% to 15% of people with diabetes met treatment guidelines for good glycemic control, and more than 20% had very poor glycemic control. The CDC estimated that as of 2006, 63.4% of all adults with diabetes were monitoring their blood glucose levels on a daily basis, and that 86.7% of insulin-requiring patients with diabetes monitored daily.

Various clinical studies also demonstrate the benefits of continuous glucose monitoring and that continuous glucose monitoring is equally effective in patients who administer insulin through multiple daily injections or through use of continuous subcutaneous insulin infusion pumps. Results of a Juvenile Diabetes Research Foundation study published in the New England Journal of Medicine in 2008, and the extension phase of the study, published in Diabetes Care in 2009, demonstrated that continuous glucose monitoring improved A1c levels and reduced incidence of hypoglycemia for patients over the age of 25 and for all patients of all ages who utilized continuous glucose monitoring regularly.

Our initial target market in the United States consists of the estimated 30% of people with Type 1 diabetes who utilize insulin pump therapy and the estimated 50% of people with Type 1 diabetes who utilize multiple daily insulin injections. Our broader target market in the United States consists of our initial target market plus an estimated 20% of people with Type 1 diabetes using conventional insulin therapy and the estimated 27% of people with Type 2 diabetes who require insulin. Although our initial focus was within the United States, we have expanded our operations to include Canada, Australia, New Zealand, and portions of Europe, Asia, Latin America, the Middle East and Africa.

Products

Ambulatory Product Line: SEVEN ^® PLUS, DexCom G4 ^® , DexCom G4 ^® PLATINUM, DexCom Share ^TM System and DexCom G5 ^® Mobile

We received approval from the Food and Drug Administration (“FDA”) and commercialized our first product in 2006. In 2009 we received approval and began commercializing our third generation system, the DexCom SEVEN PLUS. We no longer market or provide support for the DexCom SEVEN PLUS system. On June 14, 2012, we received Conformité Européenne Marking (“CE Mark”) approval for our fourth generation continuous glucose monitoring system, the DexCom G4 system, enabling commercialization of the DexCom G4 system in the European Union, Australia, New Zealand and the countries in Asia and Latin America that recognize the CE Mark . On October 5, 2012, we received approval from the FDA for the DexCom G4 PLATINUM, which is designed for up to seven days of continuous use by adults with diabetes, and we began commercializing this product in the United States in the fourth quarter of 2012. On February 14, 2013, we received CE Mark approval for a pediatric indication for our DexCom G4 system, enabling us to market and sell this system to persons two years old and older who have diabetes (hereinafter referred to as the “Pediatric Indication”) , and we initiated a limited commercial launch in the second quarter of 2013. In connection with our receipt of CE Mark approval for the Pediatric Indication , we changed the name of the DexCom G4 system to the DexCom G4 PLATINUM system. On February 3, 2014, we received approval from the FDA for a Pediatric Indication for the DexCom G4 PLATINUM system in the United States. On June 3, 2014, we received approval from the FDA for an expanded indication for the DexCom G4 PLATINUM for professional use. This expanded indication allows healthcare professionals to purchase the DexCom G4 PLATINUM system for use with multiple patients. Healthcare professionals can use the insights gained from a DexCom G4 PLATINUM professional session to adjust therapy and to educate and motivate patients to modify their behavior after viewing the effects that specific foods, exercise, stress, and medications have on their glucose levels. On January 23, 2015, we received approval from the FDA for the DexCom G4 PLATINUM with Share, which is designed for up to seven days of continuous use, and we began commercializing this product in the United States in the first quarter of 2015. The DexCom G4 PLATINUM with Share remote monitoring system uses a secure wireless connection between a patient's receiver and an app on the patient's iPhone ^® , iPod touch ^® , or iPad ^® mobile digital device to transmit glucose information to apps on the mobile devices of up to five designated recipients, or “followers,” who can remotely monitor a patient's glucose information and receive alert notifications anywhere they have an Internet or cellular connection. Unless the context requires otherwise, the term “G4 PLATINUM” shall refer to the DexCom G4 and DexCom G4 PLATINUM systems (and all associated indications of use for such systems including without limitation, associated DexCom Share System functionalities) that are commercialized by us in and outside of the United States.

As compared to the SEVEN PLUS, the G4 PLATINUM offers:

DexCom SHARE ^TM  

On October 17, 2014, we received approval from the FDA for the DexCom SHARE remote monitoring system. DexCom SHARE enables users of our G4 PLATINUM System to have their sensor glucose information remotely monitored by their family or friends. To use DexCom SHARE, the G4 PLATINUM user docks their G4 PLATINUM Receiver in the DexCom SHARE Cradle and their sensor glucose information is wirelessly transmitted to, and viewed by, such patient’s friends or family through the DexCom SHARE mobile application. DexCom SHARE provides secondary notifications to individuals designated by a G4 PLATINUM System user and does not replace real time continuous glucose monitoring or standard home blood glucose monitoring.

On January 23, 2015, the FDA approved a version of the G4 PLATINUM Receiver that includes the DexCom Share System. The G4 PLATINUM Receiver with Share remote monitoring system uses a secure wireless connection via Bluetooth Low Energy between a patient's receiver and a mobile application on the patient's iPhone, iPod touch, or iPad mobile digital device to transmit glucose information to mobile applications on the mobile devices of up to five designated recipients, or “followers,” without the need to use the DexCom SHARE Cradle component. The mobile applications that comprise the DexCom Share System were classified by the FDA as Class II, exempt, due to the fact that these mobile applications were secondary displays of the associated G4 PLATINUM Receiver. With the mobile applications classified as Class II, exempt, DexCom must comply with certain general and special controls required by the FDA but does not need prior FDA approval to commercialize changes to the DexCom Share System. We began commercialization of the G4 PLATINUM with Share in the first quarter of 2015 and discontinued the DexCom SHARE Cradle. Effective April 24, 2015, our DexCom Share System also supports the Apple Watch ^TM , allowing the Apple Watch to utilize DexCom Share System functionality. Effective June 2, 2015, the mobile application for the Share System followers became available for Android devices.

DexCom G5 Mobile

On August 19, 2015, we received approval from the FDA for the DexCom G5 Mobile Continuous Glucose Monitoring System (the “G5 Mobile”). The G5 Mobile is designed to allow our transmitter to run the algorithm that has historically operated on the receiver, and to communicate directly to a patient's iPhone, iPod touch, or iPad mobile digital device to utilize DexCom Share System functionality. The G5 Mobile transmitter has a labeled useful life of three months.

We previously received CE Mark approval for, and in September, 2015, we launched the G5 Mobile in certain countries in Europe. In the countries and regions outside of the United States that recognize the CE Mark, the G5 Mobile does not require confirmatory finger sticks when making treatment decisions, although a minimum of two finger sticks a day remain necessary for calibration of the G5 Mobile.

Data from the G5 Mobile can be integrated with DexCom CLARITY ^TM , our next generation cloud-based reporting software, for personalized, easy-to-understand analysis of trends that may improve diabetes management.

Except with respect to the foregoing, the G5 Mobile is equivalent to the G4 PLATINUM System in technical and regulatory respects.

SweetSpot

Through our acquisition of SweetSpot in 2012, we have a software platform that enables our customers to aggregate and analyze data from certain diabetes devices and to share it with their healthcare providers. In November 2011, SweetSpot received 510(k) clearance from the FDA to market to clinics its initial cloud-based data management service, which helps healthcare providers and patients see, understand and use blood glucose meter data to diagnose and manage diabetes. SweetSpot has also developed a data transfer service that is registered with the FDA as a Medical Device Data System . This data transfer service allows researchers to control the transfer of data from certain diabetes devices to research tools and databases according to their own research workflows. SweetSpot’s software provides an advanced cloud-based platform for uploading, processing and delivering health data and transforms raw output from certain medical devices into useful information for healthcare providers, individuals and researchers.

Sensor Augmented Insulin Pumps

We are leveraging our technology platform to enhance the capabilities of our current products and to develop additional continuous glucose monitoring products. In 2008 and 2015, we entered into development agreements with Animas Corporation (“Animas”) , a subsidiary of Johnson & Johnson, and in 2012 and 2015 we entered into development agreements with Tandem Diabetes Care, Inc. (“Tandem”) . The purpose of each of these development relationships is to integrate our technology into the insulin pump product offerings of the respective partner, enabling the partner's insulin pump to receive glucose readings from our transmitter and display this information on the pump's screen. The Animas insulin pump product augmented with our sensor technology has been branded the Vibe®, and received CE Mark approval in May 2011, which allows Animas to market the

Vibe in the countries that recognize CE Mark approvals. In December 2014, Animas received FDA approval for the VIBE system in the United States and began commercializing this product in 2015. In July 2014, Tandem filed their submission for FDA approval of their CGM-enabled insulin pump in the United States. In September 2015 Tandem announced it had received FDA approval of its t:slim G4™ Insulin Pump, a touch-screen pump that is integrated with our G4 PLATINUM system and is indicated for use by people 12 years of age or older who use insulin. Tandem began commercializing this product in September 2015.

Future Products

We plan to develop future generations of technologies focused on improved performance and convenience and that will enable intelligent insulin administration. Over the longer term, we plan to develop networked platforms with open architecture, connectivity and transmitters capable of communicating with other devices and software systems. Our product development timelines are highly dependent on our ability to achieve clinical endpoints and regulatory and legal requirements and to overcome technology challenges, and our product development timelines may be delayed due to extended regulatory approval timelines, scheduling issues with patients and investigators, requests from institutional review boards, sensor performance and manufacturing supply constraints, among other factors. In addition, support of these clinical trials requires significant resources from employees involved in the production of our products, including research and development, manufacturing, quality assurance, and clinical and regulatory personnel. Even if our development and clinical trial efforts are successful, the FDA may not approve our products, and even if approved, we may not achieve acceptance in the marketplace by physicians and people with diabetes.

On August 10, 2015, we entered into a Collaboration and License Agreement (the “Verily Collaboration Agreement”) with Google Life Sciences LLC, now named Verily Life Sciences (“Verily”). Pursuant to the Verily Collaboration Agreement, we and Verily have agreed to jointly develop a series of next-generation continuous glucose monitoring products. The Verily Collaboration Agreement provides us with an exclusive license to use certain intellectual property of Verily related to the development, manufacture and commercialization of the products contemplated under the Verily Collaboration Agreement. The Verily Collaboration Agreement provides for the establishment of a joint steering committee, joint development committee and joint commercialization committee to oversee and coordinate the parties’ activities under the collaboration. We and Verily have agreed to make committee decisions by consensus.

Commercial Operations

We have built a direct sales organization in the United States, and are building a direct sales force in Europe, to call on endocrinologists, pediatric endocrinologists, physicians, pediatricians and diabetes educators who can educate and influence patient adoption of continuous glucose monitoring. We believe that focusing efforts on these participants is important given the instrumental role they each play in the decision-making process for diabetes therapy. To complement our direct sales efforts, we have entered into U.S. and international distribution arrangements that allow distributors to sell our products. We believe our direct, highly specialized and focused sales organization and our domestic and international distribution agreements are sufficient for us to support our sales efforts for at least the next twelve months.

As a medical device company, reimbursement from Medicare and private third-party healthcare payors is an important element of our success. Although the Centers for Medicare and Medicaid (“CMS”) released 2008 Alpha-Numeric Healthcare Common Procedure Coding System (“HCPCS”) codes applicable to each of the three components of our continuous glucose monitoring systems, to date, our approved products are not reimbursed by virtue of a national coverage decision by Medicare. It is not known when, if ever, Medicare will adopt a national coverage decision with respect to continuous glucose monitoring devices. Until any such coverage decision is adopted by Medicare, reimbursement of our products will generally be limited to those customers covered by third-party payors that have adopted coverage policies for continuous glucose monitoring devices that include our products. As of April 27, 2016 , the seven largest private third-party payors, in terms of the number of covered lives, have issued coverage policies for the category of continuous glucose monitoring devices. In addition, we have negotiated contracted rates with all seven of those third-party payors for the purchase of our G4 PLATINUM and G5 Mobile systems by their members. Many of these coverage policies reimburse for our products under durable medical equipment benefits, are restrictive in nature and require the patient to comply with extensive documentation and other requirements to demonstrate medical necessity under the policy. In addition, customers who are insured by payors that do not offer coverage for our devices will have to bear the financial cost of the products. We currently employ in-house reimbursement expertise to assist customers in obtaining reimbursement from private third-party payors. We also maintain a field-based reimbursement team charged with calling on third-party private payors to obtain coverage decisions and contracts. We have had formal meetings and have increased our efforts to create and liberalize coverage policies with third-party payors, including obtaining reimbursement for our products under pharmacy benefits, and expect to continue to do so in fiscal 2016. However, unless government and other third-party payors provide adequate coverage and reimbursement for our products, people with diabetes may not use them on a widespread basis.

We currently manufacture our products at our headquarters facilities in San Diego, California. As of March 31, 2016 , these facilities had more than 8,000 square feet of laboratory space and approximately 18,000 square feet of controlled environment rooms. In July 2012, the FDA completed an inspection of our facilities, and did not identify any observations or require any other types of corrective action. During a routine FDA post-approval facility inspection ending on November 7, 2013, the FDA issued a Form 483 with several observations regarding DexCom Medical Device Reporting (“MDR”) procedures and complaint reportability determinations. DexCom responded to the observations on November 26, 2013. On March 14, 2014, we received the 2014 Warning Letter from the FDA related to administrative deficiencies in filing MDR s. On April 2, 2014, we responded to the 2014 Warning Letter. On April 16, 2015, the FDA initiated an on-site inspection intended to both close out the 2014 Warning Letter and conduct our normal biennial quality system inspection. The FDA completed its inspection with no observations. On May 21, 2015, the FDA issued a letter closing the 2014 Warning Letter. During a routine FDA post-market inspection ending on March 29, 2016, the FDA issued a Form 483 with one observation regarding the DexCom MDR procedure specific to retrospective MDR filing when a change in complaint reportability is made. On April 19, 2016, we responded to this observation.

There are technical challenges to increasing manufacturing capacity, including FDA qualification of new manufacturing facilities, equipment design and automation, material procurement, problems with production yields, and quality control and assurance. We have focused significant effort on continual improvement programs in our manufacturing operations intended to improve quality, yields and throughput. We have made progress in manufacturing to enable us to supply adequate amounts of product to support our commercialization efforts, however we cannot guarantee that supply will not be constrained going forward. Additionally, the production of our continuous glucose monitoring systems must occur in a highly controlled and clean environment to minimize particles and other yield- and quality-limiting contaminants. Developing commercial-scale manufacturing facilities has and will continue to require the investment of substantial additional funds and the hiring and retaining of additional management, quality assurance, quality control and technical personnel who have the necessary manufacturing experience. Manufacturing is subject to numerous risks and uncertainties described in detail in “Risk Factors” below.

We manufacture our G4 PLATINUM and G5 Mobile systems with certain components supplied by outside vendors and other components that we manufacture internally. Key components that we manufacture internally include our wire-based sensors for the G4 PLATINUM and G5 Mobile systems. The remaining components and assemblies are purchased from outside vendors. We then assemble, test, package and ship the finished G4 PLATINUM and G5 Mobile systems, which include a reusable transmitter, a receiver, disposable sensors and our mobile applications including functionality related to the DexCom Share System.

Product revenues are generated from the sale of durable continuous glucose monitoring systems (receivers and transmitters) and disposable sensors through a direct sales force in the United States as well as through distribution arrangements in the United States, Canada, Australia, New Zealand, and in portions of Europe, Asia, Latin America, the Middle East and Africa. The sensor is inserted by the user and is intended to be used continuously for up to seven days, after which it may be replaced with a new disposable sensor. Our transmitter is reusable until it reaches the end of its battery life. Our receiver is reusable. As we establish an installed base of customers using our products, we expect to generate an increasing portion of our revenues through recurring sales of our disposable sensors.

As of March 31, 2016 , we had an accumulated deficit of $574.6 million . We expect our losses to continue as we proceed with our commercialization and research and development activities. We have financed our operations primarily through offerings of equity securities and debt. In November 2012, we entered into our Loan Agreement that provides for (i) a $15.0 million revolving line of credit and (ii) initially provided a total term loan of up to $20.0 million (the “Term Loan”). The revolving line of credit expired as of November 2015 with no amounts drawn or outstanding. In accordance with the Loan Agreement , $7.0 million was advanced under the Term Loan at the funding date in November 2012, and the remaining $13.0 million in additional funds expired unused.

Financial Operations

Revenue

We sell our durable systems and disposable units through a direct sales force in the United States and through distribution arrangements in the United States, Canada, Australia, New Zealand, and in portions of Europe, Asia, Latin America, the Middle East and Africa. We have contracts with certain distributors who stock our products, and we refer to these distributors as Stocking Distributors , whereby the distributors fulfill orders for our product from their inventory. We also have contracts with certain distributors that do not stock our products, but rather products are shipped directly to the customer by us on behalf of our distributor, and we refer to these distributors as Drop-Ship Distributors . We expect that revenues we generate from the sales of our products will fluctuate from quarter to quarter. We typically experience seasonality with lower sales in the first quarter of each year, compared to the previous fourth quarter, related to annual insurance deductible resets and unfunded flexible spending accounts.

Cost of Sales

Cost of sales includes direct labor and materials costs related to each product sold or produced, including assembly, test labor and scrap, as well as factory overhead supporting our manufacturing operations. Factory overhead includes facilities, material procurement and control, manufacturing engineering, quality assurance, supervision and management. These costs are primarily salary, fringe benefits, share-based compensation, facility expense, supplies and purchased services. A portion of our costs are currently fixed due to our moderate level of production volumes compared to our potential capacity. All of our manufacturing costs are included in product cost of sales.

Research and Development

Our research and development expenses primarily consist of engineering and research expenses related to our continuous glucose monitoring technology, clinical trials, regulatory expenses, quality assurance programs, materials and products for clinical trials. Research and development expenses are primarily related to employee compensation, including salary, fringe benefits, share-based compensation, and temporary employee expenses. We also incur significant expenses to operate our clinical trials including clinical site reimbursement, clinical trial product and associated travel expenses. Our research and development expenses also include fees for design services, contractors and development materials.

Selling, General and Administrative

Our selling, general and administrative expenses primarily consist of salary, fringe benefits and share-based compensation for our executive, financial, sales, marketing and administrative functions. Other significant expenses include trade show expenses, sales samples, insurance, professional fees for our outside legal counsel and independent auditors, litigation expenses, patent application expenses and consulting expenses.

Results of Operations

Quarter Ended March 31, 2016 Compared to March 31, 2015

Revenue, Cost of Sales and Gross Profit

Revenues increased $43.4 million to $116.2 million for the three months ended March 31, 2016 compared to $72.8 million for the three months ended March 31, 2015 , primarily due to increased sales volume of our disposable sensors resulting from the continued growth of our installed base of customers using our G4 PLATINUM and G5 Mobile systems and durable systems to both new and existing customers. Revenue attributable to our disposable sensors and durable systems was approximately 72% and 28% of total revenue for the three months ended March 31, 2016 , and was approximately 70% and 30% of total revenue for the three months ended March 31, 2015 .

Cost of sales increased $14.8 million to $41.1 million for the three months ended March 31, 2016 compared to $26.3 million for the three months ended March 31, 2015 , primarily due to increased sales volume, and partially due to increased warranty costs related to receivers, and the customer notification regarding the receiver speaker as discussed in the Risk Factor entitled “ If we or our suppliers or distributors fail to comply with ongoing regulatory requirements, or if we experience unanticipated problems with our products, the products could be subject to restrictions or withdrawal from the market." Gross profit increased $28.6 million to $75.1 million for the three months ended March 31, 2016 compared to $46.5 million for the same period in 2015 , primarily due to increased revenue, partially offset by the product mix of sales of our lower margin G5 transmitters.

Revenue from products shipped to our Drop-Ship Distributors ’ customers was $9.5 million , or 8% , of our total revenues for the three months ended March 31, 2016 compared to $8.4 million , or 12% , of our total revenues for the three months ended March 31, 2015 . Revenue from products shipped to Stocking Distributors was $79.4 million , or 68% , of our total revenues for the three months ended March 31, 2016 compared to $44.7 million , or 61% , of our total revenues for the three months ended March 31, 2015 .

Research and Development. Research and development expense increased $12.4 million to $32.2 million for the three months ended March 31, 2016 compared to $19.8 million for the three months ended March 31, 2015 . Significant elements of the increase in research and development costs for the three months ended March 31, 2016 compared to the three months ended March 31, 2015 included $ 3.9 million in additional salaries, bonus and payroll related costs, $3.1 million in additional share-based compensation, and $2.0 million in additional supplies.

Selling, General and Administrative. Selling, general and administrative expense increased $22.7 million to $62.1 million for the three months ended March 31, 2016 compared to $39.4 million for the three months ended March 31, 2015 . The increase was primarily due to higher headcount related selling, marketing and information technology infrastructure costs to support revenue growth and the continued commercialization of our products. Significant elements of the increase in selling,

general, and administrative expenses included $ 5.7 million in additional salaries, bonus, and payroll related costs, $ 5.0 million in additional share-based compensation costs, $ 2.9 million in additional marketing costs, $1.5 million of additional commissions, $1.4 million of additional consulting fees and $0.7 million of additional costs to support our international expansion.

Interest Expense. Interest expense was $0.1 million for the three months ended March 31, 2016 compared to $0.2 million for the three months ended March 31, 2015 and is related to our Loan Agreement.

Interest Income. Interest income of $0.1 million for the three months ended March 31, 2016 is related to our marketable securities portfolio.

Liquidity and Capital Resources

We have incurred losses since our inception in May 1999. As of March 31, 2016 , we had an accumulated deficit of $574.6 million and had working capital of $163.3 million . Our cash, cash equivalents and marketable securities totaled $106.5 million . To date, we have funded our operations primarily through offerings of equity securities and debt, and the sales of our products.

Net Cash Used in/Provided by Operating Activities . The change in cash used in operations was primarily due to an additional $7.2 million cash outflow from changes in operating assets and liabilities, and by $6.3 million in higher net loss, partially offset by $9.9 million in higher non-cash charges primarily comprised of share-based compensation. The main drivers in the change in operating assets and liabilities included increases in accounts receivable, inventory and accounts payable and accrued payroll and other liabilities, all as a result of our growth.

Net Cash Used in Investing Activities. The change in cash used in investing activities was primarily due to a $11.8 million decrease in cash used to purchase marketable securities, and by the use of $11.5 million to purchase equipment to support manufacturing improvements and information technology infrastructure for the three months ended March 31, 2016 , compared to $8.0 million to purchase equipment for the three months ended March 31, 2015 , partially offset by a $6.4 million increase in proceeds from the maturity of marketable securities.

Net Cash Provided by Financing Activities . The decrease in cash provided by financing activities was due to $1.7 million decrease in proceeds from the issuance of common stock pursuant to the exercise of then-outstanding stock options for the three months ended March 31, 2016 compared to the three months ended March 31, 2015 .

Operating Capital and Capital Expenditure Requirements

We anticipate that we will continue to incur net losses as we incur expenses and expand the commercialization of our approved products domestically and internationally, develop additional continuous glucose monitoring products, and expand our marketing, manufacturing and corporate infrastructure.

We believe that our cash, cash equivalents, marketable securities balances, and projected cash contributions from our commercial operations will be sufficient to meet our anticipated cash requirements with respect to the continued scale-up of our commercialization activities, research and development activities, including clinical trials, the expansion of our marketing, manufacturing and corporate infrastructure, and to meet our other anticipated cash needs through at least March 31, 2017 . If our available cash, cash equivalents and marketable securities are insufficient to satisfy our liquidity requirements, or if we develop additional products or new markets for our existing products, we may seek to sell additional equity or debt securities or obtain an additional credit facility. The sale of additional equity and debt securities may result in additional dilution to our stockholders. If we raise additional funds through the issuance of debt securities or preferred stock, these securities could have rights senior to those of our common stock and could contain covenants that would restrict our operations. We may require additional capital beyond our currently forecasted amounts. Any such required additional capital may not be available on reasonable terms, if at all. Additionally, we cannot guarantee that we will be successful in obtaining additional cash contributions from future partnership arrangements. Our ability to transition to, and maintain profitable operations is dependent

upon achieving a level of revenues adequate to support our cost structure. If events or circumstances occur such that we do not meet our operating plan as expected, or if we are unable to obtain additional financing, we may be required to reduce planned increases in compensation related expenses or other operating expenses related to research, development, and commercialization activities, which could have an adverse impact on our ability to achieve our intended business objectives.

Because of the numerous risks and uncertainties associated with the development of continuous glucose monitoring technologies, we are unable to estimate the exact amounts of capital outlays and operating expenditures associated with our current and anticipated clinical trials. Our future funding requirements will depend on many factors, including, but not limited to:

Contractual Obligations

We are party to various purchase arrangements related to components used in manufacturing and research and development activities. As of March 31, 2016 , we had firm purchase commitments with certain vendors totaling approximately $58.4 million due within one year. There are no material purchase commitments due beyond one year.

Off-Balance Sheet Arrangements

We have not engaged in any off-balance sheet activities.

Critical Accounting Policies and Estimates

The discussion and analysis of our financial condition and results of operations are based on our consolidated financial statements, which we have prepared in accordance with U.S. GAAP . The preparation of these consolidated financial statements requires us 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 as well as the reported revenue and expenses during the reporting periods. On an ongoing basis, we evaluate our estimates and judgments. We base our estimates on historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

Our significant accounting policies are more fully described in Note 1 to our consolidated financial statements included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2015. Our accounting policies and estimates which are most critical to a full understanding and evaluation of our reported financial results are described in the Management’s Discussion and Analysis of Financial Condition and Results of Operations in Item 7 of our Annual Report on Form 10-K for the fiscal year ended December 31, 2015. There were no material changes to our critical accounting policies during the three months ended March 31, 2016 .

Recent Accounting Guidance

In May 2014, the FASB issued authoritative guidance for Revenue from Contracts with Customers, to supersede nearly all existing revenue recognition guidance under U.S. GAAP . The core principle of the guidance is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. The guidance defines a five step process to achieve this core principle and it is possible when the five step process is applied, more judgment and estimates may be required within the revenue recognition process than required under existing U.S. GAAP including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The updated standard permits the use of either the retrospective or cumulative effect transition method and is effective for us in our first quarter of fiscal 2018. Early adoption is not permitted. We have not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures.

In July 2015, the FASB issued guidance to change the subsequent measurement of inventory from lower of cost or market to lower of cost and net realizable value. The guidance requires that inventory accounted for under the first-in, first-out (FIFO) or average cost methods be measured at the lower of cost and net realizable value, where net realizable value represents the estimated selling price of inventory in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The guidance is effective for us beginning in the first quarter of fiscal 2018. Earlier application is permitted as of the beginning of an interim or annual reporting period. We are currently evaluating the effect this guidance will have on our consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”), which require a lessee to recognize a lease payment liability and a corresponding right of use asset on their balance sheet for all lease terms longer than 12 months, lessor accounting remains largely unchanged. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning on or after December 15, 2018 and early adoption is permitted. We are currently evaluating the effect this guidance will have on our consolidated financial statements.

In February 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718) (“ASU 2016-09”), which is intended to simplify several areas of accounting for share-based payment arrangements. The amendments in this update cover such areas as the recognition of excess tax benefits and deficiencies, the classification of those excess benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. ASU 2016-09 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. We are currently evaluating the effect this guidance will have on our consolidated financial statements.