Year Ended December 31,
2019
2018
2017
2016
2015
Stock-based compensation expense data:
Sales and marketing
$2,075
$1,196
$561
$536
$372
General and administrative
6,474
4,901
2,638
1,430
2,486
Research and development
12,054
7,332
4,214
2,035
1,266
Total stock-based compensation expense
$20,603
$13,429
$7,413
$4,001
$4,124

text: ITEM 6. SELECTED FINANCIAL DATA
text: The selected consolidated statements 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 are derived from our audited consolidated financial statements included elsewhere in this Annual Report. The selected consolidated statements 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 not included in this Annual Report. Our historical results are not necessarily indicative of the results to be expected in the future. The selected financial data should be read together with Item 7. "Management’s Discussion and Analysis of Financial Condition and Results of Operations" and in conjunction with our consolidated financial statements, related notes, and other financial information included elsewhere in this Annual Report. The following tables set forth our selected consolidated financial and other data for the years ended and as of December 31, 2019, 2018, 2017, 2016 and 2015 (in thousands, except share and per share data).
text: Information about prior period acquisitions that may affect the comparability of the selected financial information presented below is included in Item 1. Business. Information about the $28.0 million expense recorded in general and administrative expense in 2018, which relates to the agreement reached to settle the legal matter alleging violations of the Telephone Consumer Protection Act, or TCPA, and may affect the comparability of the selected financial information presented below, is disclosed in Item 3. “Legal Proceedings.” Information about the $1.7 million of interest recorded within interest income and the $6.9 million of gain recorded within other income, net, in 2019, which relates to promissory note proceeds received from one of our hardware suppliers and proceeds from an acquired promissory note, and may affect the comparability of the selected financial information presented below, is disclosed in Item 7. "Management’s Discussion and Analysis of Financial Condition and Results of Operations."
text: Certain previously reported amounts in the consolidated statements of operations for the years ended December 31, 2018, 2017, 2016 and 2015 have been reclassified to conform to our current presentation to reflect interest income as a separate line item, which was previously included in other income, net.

Questions:
question: What years does the table provide data for sales and marketing?
answer: 2019
2018
2017
2016
2015
question: What was the amount of sales and marketing in 2018?
answer: $1,196
scale: thousand
question: What was the amount of research and development in 2018?
answer: 7,332
scale: thousand
question: How many years did the amount of general and administrative exceed $5,000 thousand?
answer: 1
derivation: 2019
question: What was the change in the amount of research and development between 2018 and 2019?
answer: 4722
derivation: 12,054-7,332
scale: thousand
question: What was the percentage change in the Total stock-based compensation expense between 2018 and 2019?
answer: 53.42
derivation: (20,603-13,429)/13,429
scale: percent