Item 6. Selected Financial Data
We have derived the consolidated statement of operations data for the years ended December 31, 2019, 2018 and 2017 and the selected consolidated balance sheet data as of December 31, 2019 and 2018 from our audited consolidated financial statements that are included in this Form 10-K. The following selected consolidated statement of operations data for the years ended December 31, 2016 and 2015 and the selected consolidated balance sheet data as of December 31, 2017, 2016 and 2015 are derived from our audited consolidated financial statements that are not included in this report
Our historical operating results are not necessarily indicative of future operating results, these selected consolidated financial data should be read in conjunction with the consolidated financial statements and accompanying notes in Part II, Item 8, and Management’s Discussion and Analysis of Financial Condition and Results of Operations in Part II, Item 7 included in this report
The amounts as of and for the years ended December 31, 2019 and 2018 have been prepared based on our adoption of Accounting Standards Codification (‘‘ASC’’) No. 606, Contracts with Customers. We elected to adopt this accounting standard on a modified retrospective basis which resulted in the impact of adoption being recorded as of January 1, 2018. The amounts in all other years, other than 2019 and 2018, in the tables below have been prepared on the previously outstanding guidance on revenue recognition. We have disclosed the ASC 606 adoption impact on our revenue recognition in Note 2 of the audited consolidated financial statements included in Part II, Item 8 of this report
The amounts as of and for the years ended December 31, 2019 and 2018 have been prepared based on our adoption of Accounting Standards Codification (‘‘ASC’’) No. 606, Contracts with Customers. We elected to adopt this accounting standard on a modified retrospective basis which resulted in the impact of adoption being recorded as of January 1, 2018. The amounts in all other years, other than 2019 and 2018, in the tables below have been prepared on the previously outstanding guidance on revenue recognition. We have disclosed the ASC 606 adoption impact on our revenue recognition in Note 2 of the audited consolidated financial statements included in Part II, Item 8 of this report
Table:
 |  | Years Ended December 31, |  |  | 
(in thousands, except per share amounts) | 2019 | 2018 | 2017 | 2016 | 2015
Consolidated Statement of Operations Data |  |  |  |  | 
Revenue | $212,628 | $232,223 | $235,429 | $227,297 | $196,285
Cost of revenue | $48,881 | $51,896 | $53,318 | $54,413 | $48,402
Gross profit | $163,747 | $180,327 | $182,111 | $172,884 | $147,883
Loss from operations | $(17,094) | $(27,679) | $(10,372) | $(20,570) | $(40,309)
Net loss | $(17,819) | $(27,617) | $(10,751) | $(22,391) | $(41,897)
Net loss per share: basic and diluted | $(0.23) | $(0.38) | $(0.15) | $(0.34) | $(0.67)
Weighted-average shares used in computing net |  |  |  |  | 
loss per share: basic and diluted | 76,080 | 72,882 | 70,053 | 65,701 | 62,428
Consolidated Balance Sheet Data: |  |  |  |  | 
Cash,cash equivalents and marketable securities | $129,922 | $128,375 | $131,134 | $114,347 | $98,117
Working capital | $123,358 | $117,572 | $111,076 | $95,285 | $89,550
Total assets | $274,053 | $235,876 | $224,858 | $216,733 | $189,892
Deferred revenue(current and non-current) | $101,164 | $97,966 | $94,637 | $91,617 | $72,008
Total stockholders’ equity | $108,787 | $103,883 | $98,386 | $82,752 | $78,205


Question: What is the accounting standards used to prepare the financial statements?
Answer: Accounting Standards Codification