2/24/2018 S-1 Table of Contents infrastructure­related costs, and marketing expenses. Net cash provided by operating activities is impacted by our net loss adjusted for certain non­cash items, including depreciation and amortization expenses and stock­based compensation, as well as the effect of changes in operating assets and liabilities. For the year ended December 31, 2017, net cash provided by operating activities was $330.3 million, which mostly consisted of our net loss of $111.7 million, adjusted for depreciation and amortization expenses of $181.8 million and stock­based compensation expense of $164.6 million, and net cash inflow of $81.3 million from operating assets and liabilities. The inflow from operating assets and liabilities was primarily due to an increase of $64.3 million in deferred revenue from increased subscription sales, as a majority of our paying users are invoiced in advance. The increase in net cash provided by operating activities during the year ended December 31, 2017, compared to the year ended December 31, 2016, was primarily due to a reduction of our net loss, as adjusted for stock­based compensation and depreciation and amortization expenses, as well as cash inflow from changes in operating assets and liabilities. For the year ended December 31, 2016, net cash provided by operating activities was $252.6 million, which primarily consisted of our net loss of $210.2 million, adjusted for depreciation and amortization expenses of $191.6 million and stock­based compensation expense of $147.6 million, as well as a net cash inflow of $118.8 million from operating assets and liabilities. The inflow from operating assets and liabilities was primarily due to an increase of $87.6 million in deferred revenue from increased subscription sales, as a majority of our paying users are invoiced in advance, and an increase of $35.6 million in accrued compensation and benefits due to the introduction of our annual bonus plan. The increase in net cash from operating activities during 2016 compared to 2015 was primarily due to a reduction of our net loss, as adjusted for stock­based compensation and depreciation and amortization expenses, as well as cash inflow from changes in operating assets and liabilities. For the year ended December 31, 2015, net cash provided by operating activities was $14.8 million, which mostly consisted of our net loss of $325.9 million, adjusted for depreciation and amortization expenses of $149.6 million and stock­based compensation expense of $66.1 million, as well as a net cash inflow of $123.6 million from operating assets and liabilities. The inflow from operating assets and liabilities was primarily due to an increase of $82.0 million in deferred revenue from increased subscription sales, as a majority of our paying users are invoiced in advance, and an increase of $50.6 million in current and non­current liabilities. Investing activities Net cash used in investing activities is primarily impacted by purchases of property and equipment, particularly for purchasing infrastructure equipment in co­location facilities that we directly lease and operate, and for making improvements to existing and new office spaces. For the year ended December 31, 2017, net cash used in investing activities was $23.9 million, which mostly consisted of capital expenditures related to our infrastructure equipment and office build­outs. The decrease in cash used in investing activities during the year ended December 31, 2017, compared to the year ended December 31, 2016, was primarily due to decreases in capital expenditures for infrastructure equipment and leasehold improvements related to our current corporate headquarters. For the year ended December 31, 2016, net cash used in investing activities was $118.0 million, which mostly consisted of capital expenditures related to our infrastructure and office build­outs. The increase in cash used in investing activities during 2016 compared to 2015 was primarily due to increases in capital expenditures and patent purchases. For the year ended December 31, 2015, net cash used in investing activities was $85.6 million, which mostly consisted of capital expenditures related to our infrastructure equipment and office build­outs. 79 https://www.sec.gov/Archives/edgar/data/1467623/000119312518055809/d451946ds1.htm 87/235