8. Stock-based Compensation

During the nine months ended September 30, 2018, we granted stock only stock appreciation rights (“SOSARs”) on 668 shares of our common stock to eligible employees. The weighted-average grant date fair value of the SOSARs was $71.87 per share with a weighted-average exercise price of $391.28 per share with some based on the closing price of common stock on the date of grant and some at a premium to the closing price ranging from 110% to 160%. The SOSARs generally vest in two equal installments on the second and third anniversary of the grant date; however, 168 SOSARs vest in three equal annual installments beginning on the first anniversary of the grant date and 175 SOSARs vest after 18 months from the grant date. During the nine months ended September 30, 2018, 395 SOSARs were exercised, 146 SOSARs were forfeited, and 1 SOSAR expired.

During the nine months ended September 30, 2018, we granted restricted stock units (“RSUs”) on 110 shares of our common stock to eligible employees. The weighted-average grant date fair value of the RSUs was $325.58 per share. The RSUs generally vest in two equal installments on the second and third anniversary of the grant date. During the nine months ended September 30, 2018, 6 RSUs vested and 19 RSUs were forfeited.

During the nine months ended September 30, 2018, we awarded 29 performance shares (“PSUs”) that are subject to service and performance vesting conditions. The PSUs had a weighted-average grant date fair value was $327.58 per share and vest based on our growth in comparable restaurant sales and average restaurant margin over defined periods. The quantity of shares that will vest range from 0% to 300% of the targeted number of shares. If the defined minimum targets are not met, then no shares will vest.

During the nine months ended September 30, 2018, 29 PSUs that were subject to service, market and performance conditions vested, and 24 shares that were subject to service, performance and/or market conditions were forfeited for failure to meet the specified performance levels or service requirements.

We estimate forfeitures when determining the amount of stock-based compensation costs to be recognized in each period. As a result of the transition of employees in connection with the corporate restructuring described in Note 5. “Corporate Restructuring Costs,” we reduced our estimate of the number of certain SOSAR and RSU awards that we expect will vest, resulting in a cumulative adjustment to reduce expense of $5,360. In July 2018, in connection with the restructuring, we modified service requirements for certain SOSAR and RSU awards for approximately 340 employees, resulting in additional expense of $5,021 during the nine months ended September 30, 2018. We expect that the modification will result in a total estimated expense of $7,000 and will be recognized over various employee service periods through the first quarter of 2019.

The following table sets forth total stock-based compensation expense:



	Three months ended				Nine months ended
	September 30,				September 30,
	2018		2017		2018		2017
Stock-based compensation expense	$	24,760	$	18,069	$	48,796	$	55,545
Stock-based compensation expense, net of tax	$	18,161	$	10,983	$	35,792	$	33,760
Stock-based compensation expense recognized as capitalized development	$	186	$	319	$	577	$	949
Excess tax benefit (deficit) on stock-based compensation recognized in provision for income taxes	$	(181)	$	(77)	$	(6,155)	$	587