Table:
|  |  | Fiscal Years |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Risk-free interest rate | 2.8% | 2.3% | 1.9% |
| Expected term (years) | 3.9 | 3.4 | 7.0 |
| Expected volatility | 51.9% | 45.8% | 32.3% |
| Target price | $53.87 | $98.99 | $67.39 |
Paragraphs:
Stock Options with Market-based Vesting Criteria
We grant NQs that are subject to vesting only upon the market price of our underlying public stock closing above a certain price target withins even years of the date of grant. Share-based compensation expense is recognized regardless of the number of awards that are earned based on the market condition and is recognized on a straight-line basis over the estimated service period of approximately three years.
If the required service period is not met for these options, then the share-based compensation expense would be reversed. In the event that our common stock achieves the target price per share based on a 30-day trailing average prior to the end of the estimated service period, any remaining unamortized compensation cost will be recognized.
Stock options with market-based vesting criteria granted for fiscal years 2019, 2018 and 2017 were 585,000, 325,000 and 320,000, respectively, at weighted average grant date fair values of $7.47, $15.52 and $13.18 per share, or total grant date fair value $2.4 million, $5.0 million and $4.3 million, respectively.
These NQs with market-based vesting criteria were valued using a Monte Carlo simulation model. The weighted average Monte Carlo input assumptions used for calculating the fair value of these market-based stock options are as follows:
During our fiscal first quarter of 2019, we canceled 1,122,500 performance-based stock options with a concurrent grant of 748,328 PRSUs for 13 employees, which was accounted for as a modification. The incremental compensation cost resulting from the modification was $8.2 million, and was being recognized as share-based compensation expense over the requisite service period of three years for the new PRSU awards.
As a result of subsequent actions that resulted in forfeitures, the remaining compensation expense associated with this modification as of September 27, 2019 is $2.8 million.
Question:
When does the share-based compensation expense reverse?
Answer: If the required service period is not met for these options