Year Ended December 31,
2019
2018
2017
2016
2015
(in thousands, except shares and per share data)
Revenue
$200,882
$147,094
$104,352
$76,846
$58,720
Cost of revenue(1)
63,535
46,810
31,503
23,767
19,789
Gross profit
137,347
100,284
72,849
53,079
38,931
Operating expenses:
Sales and marketing(1)
87,731
69,608
46,998
34,847
25,925
Research and development(1)
50,024
41,305
22,241
14,765
11,521
General and administrative(1)
46,820
31,462
22,895
14,293
12,272
Total operating expenses
184,575
142,375
92,134
63,905
49,718
Operating loss
(47,228)
(42,091)
(19,285)
(10,826)
(10,787)
Other expenses, net
(4,597)
(4,628)
(302)
(484)
(599)
Loss before income taxes
(51,825)
(46,719)
(19,587)
(11,310)
(11,386)
(Provision for) benefit from income taxes
(425)
(796)
(47)
24
562
Net loss
$(52,250)
$(47,515)
$(19,634)
$(11,286)
$(10,824)
Net loss per share attributable to common shareholders - basic and diluted
$(1.58)
$(1.63)
$(0.70)
$(0.68)
$(0.88)
Weighted average shares outstanding - basic and diluted
33,161,656
29,107,267
27,862,375
16,659,561
12,257,413

text: Item 6. Selected Financial Data.
text: SELECTED CONSOLIDATED FINANCIAL DATA
text: The following selected historical financial data should be read in conjunction with Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and our consolidated financial statements and the related notes appearing in Item 8, “Financial Statements and Supplementary Data,” of this Annual Report on Form 10-K to fully understand the factors that may affect the comparability of the information presented below.
text: The selected consolidated financial data in this section are not intended to replace the consolidated financial statements and are qualified in their entirety by the consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K.
text: The following selected consolidated statements of operations data for the years ended December 31, 2019, 2018 and 2017, and the consolidated balance sheet data as of December 31, 2019 and 2018, have been derived from our audited consolidated financial statements included elsewhere in this Annual Report on Form 10-K. The consolidated statements of operations data for the years ended December 31, 2016 and 2015 and the consolidated balance sheet data as of December 31, 2017, 2016 and 2015 have been derived from our audited consolidated financial statements not included in this Annual Report on Form 10-K. The selected consolidated financial data for the year ended December 31, 2019 and as of December 31, 2019 reflects the adoption of ASU No. 2016-02, Leases (Topic 842). The selected consolidated financial data for the years ended December 31, 2019 and 2018 and as of December 31, 2019 and 2018 reflects the adoption of ASU No. 2014-09, Revenue from Contracts with Customers. See Notes 15 and 18 of the notes to consolidated financial statements for a summary of adjustments. The summary consolidated financial data for the years ended December 31, 2018, 2017, 2016 and 2015 and as of December 31, 2018, 2017, 2016 and 2015 does not reflect the adoption of ASU 2016-02. The summary consolidated financial data for the years ended December 31, 2017, 2016 and 2015 and as of December 31, 2017, 2016 and 2015 does not reflect the adoption of ASU 2014-09.

Questions:
question: What was the revenue in 2019 and 2018?
answer: 200,882
147,094
scale: thousand
question: What was the cost of revenue in 2019?
answer: 63,535
scale: thousand
question: What was the Gross profit in 2018?
answer: 100,284
scale: thousand
question: In which year was revenue less than 100,000 thousands?
answer: 2016
2015
derivation: locate and analyze revenue in row 4
question: What is the average cost of revenue from 2015-2019?
answer: 37080.8
derivation: (63,535 + 46,810 + 31,503 + 23,767 + 19,789) / 5
scale: thousand
question: What is the change in the Gross Profit from 2018 to 2019?
answer: 37063
derivation: 137,347 - 100,284
scale: thousand