Thank you, Gary. I will be describing our results on a non-GAAP or pro forma basis, which excludes the impact of our prior year Xi trade-in programs, legal claim accruals, stock-based compensation, amortization of purchased IP, and investment impairments. We provide pro forma information because we believe that business trends and operating results are easier to understand on a pro forma basis. I will also summarize our GAAP results later in my script. We've posted reconciliations of our pro forma results to our GAAP results on our website so that there's no confusion. Pro forma second quarter revenue was $586 million, an increase of 16% compared with $507 million for the second quarter of 2014, and an increase of 10% compared with last quarter. Pro forma revenue for the second quarter of 2014 excludes net revenue associated with offers made in 2014 to trade out Si product for Xi product. All trade out offers were either fulfilled or lapsed in 2014. Second quarter procedures of approximately 162,000 grew nearly 14% compared with the second quarter of 2014 and approximately 8% compared with the first quarter of 2015. Revenue highlights are as follows. Pro forma, instrument, and accessory revenue grew 13% compared with the second quarter of 2014 and increased 7% compared with the first quarter 2015. The increase relative to the prior year reflects procedure growth and customer buying patterns, partially offset by the impact of foreign exchange. The increase relative to the prior quarter primarily reflects procedure growth. Instrument and accessory revenue realized per procedure including initial stocking orders was approximately $1,830 per procedure, approximately the same as the second quarter of 2014 and similar to the approximately $1,840 last quarter. Pro forma system revenue of $176 million increased 27% compared with the second quarter of 2014 and increased 25% compared with the first quarter of 2015. The increase relative to the prior year reflects increased unit sales, partially offset by the impact of foreign exchange. The increase compared with the first quarter primarily reflects increased unit sales. 118 systems were placed in the second quarter compared with 96 systems in the second quarter of 2014, and 99 systems last quarter. 64% of the systems placed in the second quarter were Xis compared with 52% in the second quarter of 2014, and 76% in the first quarter of 2015. We sold more Sis in the quarter than the previous quarter, reflecting seven Si system sales under a contract with the Department of Defense, and eight Si system sales in Japan. We expect the mix of Xi to Si product to fluctuate quarter-to-quarter. Service revenue of $113 million increased 6% year-over-year and decreased $1 million compared with the first quarter of 2015. The year-over-year increase reflects the increase in our installed base. The decrease compared with the first quarter reflects the timing of service contract renewals and changes in foreign exchange rates, partially offset by an increase in our installed base. Globally, our system ASP of $1,500,000 was approximately the same as the second quarter of last year, and increased relative to the first quarter ASP of $1,480,000. Relative to the second quarter of 2014, higher ASPs were primarily associated with higher mix of Xis, offset by the impact of the strengthened dollar. The increase in ASPs relative to last quarter reflects geographic mix and lower trade-in activity. ASPs will fluctuate on a geographic and product mix, trade-in volume, and changes in foreign exchange rates. Hospitals financed approximately 21% of the systems placed in the second quarter, up from 14% last quarter. We directly financed 12 systems, of which five were structured as operating leases. Several customers bought out previously leased systems in the quarter. Although revenue associated with the buyouts are included in total revenue, we've excluded this revenue from the computation of system ASPs. We have also excluded these buyouts from the system placement number. In the U.S., we placed 72 systems in the second quarter, compared with 61 systems in the second quarter of 2014 and 63 systems in the first quarter of 2015. As previously noted, second quarter system placements in the U.S. included seven systems sold under our Department of Defense contract. In general, the increase in system placements relative to the prior year reflect growth in procedures and market acceptance of the Xi system. Outside of the U.S., results were as follows; second quarter pro forma revenue outside the U.S. of $168 million grew 25% compared with $135 million for the second quarter of 2014, and grew 12% compared with $150 million last quarter. The increase compared with the previous year reflects higher Japan system revenue, higher instrument and accessory revenue reflecting procedure growth, partially offset by foreign exchange. The increase compared with last quarter reflects higher Japan systems placements, geographic mix of system placements, and procedure growth. Outside the U.S., we placed 46 systems in the second quarter compared with 35 in the second quarter of 2014 and 36 systems last quarter. o-US system placements reflect 13 systems into Japan this quarter compared with five systems in the second quarter of 2014, and one last quarter. We obtained Xi approval in Japan in late March, and five of the systems sold this quarter were Xi systems. European system placements grew to 22 systems this quarter compared with 19 last year and 18 last quarter. We placed no systems into China this quarter compared with one in the second quarter of 2014 and eight last quarter. As we have indicated in the past, and consistent with our history, system placements in our o-US markets will fluctuate quarter-to-quarter. Moving on to the remainder of the P&L, pro forma gross margin in the second quarter of 2015 was 68% compared with 69.2% for the second quarter of 2014 and 65.6% for the first quarter of 2015. The decline in gross margins relative to the second quarter of 2014 is primarily attributable to foreign exchange and a higher mix of newer products, including Xi and stapling. The sequential improvement in gross margin is primarily attributable to the completion of activities that resulted in one-time charges in the first quarter and cost of sales efficiency gains. In 2014, we recorded pretax charges of approximately $82 million, representing the estimated cost of settling a number of product liability legal claims under a tolling agreement. During 2015, we have refined our estimate of the overall cost of settling claims and recorded additional charges of approximately $7 million in each of the first and second quarters. These charges are excluded from our pro forma results and are included in our GAAP results. We will continue to refine our estimates as we proceed through the negotiation process. Pro forma operating expenses, which exclude the reserves for legal claims, stock compensation expense, and amortization of purchased IP, increased 10% compared with the second quarter of 2014 and increased 4% compared with last quarter. The year-over-year increase of pro forma operating expenses primarily reflects headcount additions and higher incentive compensation. Our pro forma effective tax rate for the second quarter was 25.6% compared with an effective tax rate of 29.8% for the second quarter of 2014 and 28.9% last quarter. The effective tax rate for the second quarter of 2015 benefited from approximately $8 million, or the equivalent of $0.21 per share of discrete items, including the release of reserves specific to tax years where we recently completed audits. Our tax rate will fluctuate with changes in the mix of U.S. and o-US income, and will not reflect a federal research and development credit, unless such credit is reinstated. Our pro forma net income was $173 million or $4.57 per share compared with $140 million or $3.73 per share for the second quarter of 2014 and $135 million or $3.57 per share for the first quarter of 2015. As I indicated earlier, pro forma income provides an easier comparison of our financial results and business trends. I will now summarize our GAAP results. GAAP revenue was $586 million for the second quarter of 2015 compared with $512 million for the second quarter of 2014 and $532 million for the first quarter of 2015. GAAP net income was $135 million or $3.56 per share for the second quarter of 2015, compared with $104 million or $2.77 per share for the second quarter of 2014 and $97 million or $2.57 per share for the first quarter of 2015. We ended the quarter with cash and investments of $2.9 billion, up from $2.7 billion as of March 31, 2015. The increase was primarily driven by cash generated by operations and proceeds from stock option exercises, partially offset by stock buyback. During the quarter we repurchased approximately 100,000 shares for $49 million at an average purchase price of $494 per share. And with that I would like to turn it over to Calvin who will go over our procedure and clinical highlights and provide 2015 financial guidance.