Stock-Based Compensation

6 Months Ended

May 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Stock-Based Compensation

Stock Options. We estimate the grant-date fair value of stock options using the Black-Scholes option-pricing model. The following table summarizes stock option transactions for the six months endedMay 31, 2017:

	Options		Weighted Average Exercise Price
Options outstanding at beginning of period	12,731,545		$	18.95
Granted	—		—
Exercised	(255,623	)	11.93
Cancelled	(344,528	)	18.26
Options outstanding at end of period	12,131,394		$	19.12
Options exercisable at end of period	10,082,581		$	19.87

As of May 31, 2017, the weighted average remaining contractual life of stock options outstanding and stock options exercisable was 4.0 years and 3.0 years, respectively. There was $2.1 million of total unrecognized compensation expense related to unvested stock option awards as of May 31, 2017 that is expected to be recognized over a weighted average period of 1.3 years. For the three months ended May 31, 2017 and 2016, stock-based compensation expense associated with stock options totaled $.3 million and $1.1 million, respectively. For the six-month periods ended May 31, 2017 and 2016, stock-based compensation expense associated with stock options totaled $1.1 million and $2.0 million, respectively. The aggregate intrinsic values of stock options outstanding and stock options exercisable were $62.8 million and $51.4 million, respectively, at May 31, 2017. (The intrinsic value of a stock option is the amount by which the market value of a share of the underlying common stock exceeds the exercise price of the stock option.)

Other Stock-Based Awards. From time to time, we grant restricted stock and PSUs to various employees as a compensation benefit. We recognized total compensation expense of $3.6 million and $3.5 million for the three months ended May 31, 2017 and 2016, respectively, related to restricted stock and PSUs. We recognized total compensation expense of $5.9 million and $5.5 million for the six-month periods ended May 31, 2017 and 2016, respectively, related to restricted stock and PSUs.

Director Awards. On April 13, 2017, we granted equity awards to our non-employee directors under our Non-Employee Directors Compensation Plan and pursuant to the respective elections each director made thereunder. The equity awards consisted of 22,994 shares of our common stock that were issued on an unrestricted basis to the respective directors on the grant date, and 43,499 shares that will be paid out on the earlier of a change in control or the date the respective directors leave our board.