Table:
|  |  | Years Ended December 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Stock-based compensation by type of award: |  |  |  |
| Stock options | $648 | $1,353 | $2,705 |
| Stock awards | 14,882 | 10,445 | 11,421 |
| Employee stock purchase rights(1) | 999 | 5,240 | 3,077 |
| Total | $16,529 | $17,038 | $17,203 |
| Stock-based compensation by category of expense: |  |  |  |
| Cost of revenue | $1,500 | $1,602 | $1,362 |
| Sales and marketing | 5,765 | 5,667 | 6,075 |
| Research and development | 6,039 | 6,631 | 6,343 |
| General and administrative | 3,225 | 3,138 | 3,423 |
| Total | $16,529 | $17,038 | $17,203 |
Paragraphs:
Stock-Based Compensation
A summary of our stock-based compensation expense is as follows (in thousands):
(1) Amount for the year ended December 31, 2018 includes $4.1 million of accelerated stock-based compensation expense. In March 2018, as
a result of a suspension of the 2014 Purchase Plan due to our non-timely filing status, all unrecognized stock-based compensation expense
related to ESPP under the 2014 Purchase Plan was accelerated and recognized within the consolidated statement of operations.
As of December 31, 2019, we had $29.5 million of unrecognized stock-based compensation expense related to
unvested stock-based awards, including ESPP under our Amended 2014 Purchase Plan, which will be recognized
over a weighted-average period of 2.6 years.
Question:
What is the percentage change in total stock base compensation  by type of award between 2018 and 2019?
Answer: (16529 - 17038)/17038  = -2.99