Table:
0
A
B
C
D
1
Years Ended December 31,
2
2019
2018
2017
3
(in thousands)
4
Revenue:
5
Royalty and license fees
$198,124
$219,708
$167,923
6
Total revenue
198,124
219,708
167,923
7
Operating expenses:
8
Cost of revenues
8,460
13,291
6,308
9
Research, development and other related costs
83,613
78,892
75,809
10
Litigation
1,656
—
288
11
Amortization
88,075
88,544
90,340
12
Total operating expenses (1)
181,804
180,727
172,745
13
Total operating income (loss)
$16,320
$38,981
$(4,822)

Questions and formulas:
Question: What is the overall proportion of litigation and amortization expense over the total operating expense in 2019?
Formula: (B10+B11)/B12
Formula2: (B10+B11)/B12
Level: Calculation
Question: What is the percentage change in total revenue in 2019 compared to 2018?
Formula: (B6-C6)/C6
Formula2: (B6-C6)/C6
Level: Calculation
Question: What is the average total operating expense from 2017 to 2019?
Formula: (D12+C12+B12)/3
Formula2: (D12+C12+B12)/3
Level: Calculation