For the Year Ended December 31,
2018
2017
Change
% Change
(In millions, except percentages)
Revenues
$82.3
$50.5
$31.8
63%
Cost of revenues
15.3
6.0
9.3
155%
Gross profit
67.0
44.5
22.5
51%
Gross margin
81%
88%
Operating expenses:
Selling, general and administrative
32.2
28.6
3.6
13%
Research and development
2.1
1.5
0.6
40%
Total operating expenses
34.3
30.1
4.2
14%
Other income (expense)
(4.0)
2.2
(6.2)
(282)%
Income before income taxes
28.7
16.6
12.1
73%
Income tax provision (benefit)
8.0
(6.2)
14.2
(229)%
Net income
$20.7
$22.8
$(2.1)
(9)%

text: Year ended December 31, 2018 compared with the year ended December 31, 2017:
text: Revenue in 2018 is derived from multiple license agreements that we entered into with third-parties following negotiations pursuant to our patent licensing and enforcement program. The revenue increase is primarily due to licensing revenues, as further described in "Item 1. Business" - "Licensing and Enforcement - Current Activities, Post 2013".
text: Cost of revenues includes contingent legal fees directly associated with our licensing and enforcement programs. Cost of revenues increased largely in proportion to increase in revenues.
text: Selling, general and administrative expenses ("SG&A") consisted primarily of legal fees incurred in operations and employee headcount related expenses. These comprise approximately 74% of total SG&A expense. Litigation expenses increased $4.2 million to $16.5 million in 2018 compared to 2017 and are primarily due to the timing of various outstanding litigation actions. See "Item 3. Legal Proceedings". Employee headcount related expenses increased $1.8 million to $7.2 million in 2018 compared to 2017, and is primarily due to incentive bonuses earned during the year. The balance of SG&A expenses include consulting, other professional services, facilities and other administrative fees and expenses.
text: Research and Development expenses ("R&D") are primarily from our Finjan Mobile security business and increased by $0.6 million to $2.1 million in 2018 compared to 2017, as we continue to position this business for future growth.
text: Other income (expense) is primarily due to changes in the fair value of the warrant liability of $3.4 million in 2018 versus a benefit of $2.2 million in 2017, and interest expense of $0.6 million in 2018, net.
text: We recognized an income tax expense of $8.1 million on pre-tax income of $28.7 million in 2018 as compared to a benefit from the reduction in the valuation allowance of $6.2 million in 2017.

Questions:
question: What are the respective increase in R&D expenses between 2017 and 2018, as well as the R&D expenses in 2018?
answer: $0.6 million
$2.1 million
question: What are the respective fair value of the warrant liability and interest expense in 2018?
answer: $3.4 million
$0.6 million
question: What are the respective income tax expense and pre-tax income in 2018?
answer: $8.1 million
$28.7 million
question: What is the value of pre-tax income as a percentage of revenues in 2018?
answer: 34.87
derivation: 28.7/82.3
scale: percent
question: What is the value of the warrant liability fair value as a percentage of the cost of revenues in 2018?
answer: 22.22
derivation: 3.4/15.3
scale: percent
question: What is the value of R&D expenses as a percentage of the cost of revenues in 2018?
answer: 13.73
derivation: 2.1/15.3 
scale: percent