Common Stock and Stock Plans (Tables)

12 Months Ended

Mar. 31, 2018

Summary of Stock-based Compensation Expense

Total stock-based compensation expense recognized in accordance with the authoritative guidance for share-based payments was as follows:

	Fiscal Years Ended
	March 31, 2018			March 31, 2017			March 31, 2016
	(In thousands)
Stock-based compensation expense before taxes	$	68,545		$	55,775		$	47,510
Related income tax benefits		(16,278	)		(21,057	)		(18,089	)
Stock-based compensation expense, net of taxes	$	52,267		$	34,718		$	29,421

Summary of Employee Stock Options and Employee Stock Purchase Plan Weighted Average Assumptions

The weighted average estimated fair value of TSR performance stock options granted during fiscal year 2018 was $32.04 per share, using the Monte Carlo simulation. The weighted average estimated fair value of employee stock options granted and employee stock purchase plan shares issued during fiscal year 2018 was $19.86 and $15.09 per share, respectively, during fiscal year 2017 was $23.62 and $16.27 per share, respectively, and during fiscal year 2016 was $20.35 and $13.37 per share, respectively, using the Black-Scholes model. The weighted average assumptions (annualized percentages) used in the Black-Scholes model and Monte Carlo simulation were as follows:

	Employee Stock Options									TSR Performance Stock Options			Employee Stock Purchase Plan
	Fiscal Year 2018			Fiscal Year 2017			Fiscal Year 2016			Fiscal Year 2018 *			Fiscal Year 2018			Fiscal Year 2017			Fiscal Year 2016
Volatility		30.4	%		33.4	%		32.9	%		27.5	%		22.0	%		31.1	%		24.6	%
Risk-free interest rate		1.9	%		1.7	%		1.7	%		1.9	%		1.3	%		0.5	%		0.3	%
Dividend yield		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%
Expected life	5.4 years			5.5 years			5.5 years			5.0 years			0.5 years			0.5 years			0.5 years

*	The Company began granting TSR performance stock options to executive officers in the third quarter of fiscal year 2018.

Summary of Employee Stock Option Activity and TSR Performance Stock Option Activity

A summary of employee stock option activity for fiscal year 2018 is presented below:

	Number of Shares			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2017		2,004,262		$	58.99
Options granted		53,000			63.59
Options canceled		(3,750	)		65.86
Options exercised		(287,012	)		46.59
Outstanding at March 31, 2018		1,766,500		$	61.13		3.05	$	10,279
Vested and exercisable at March 31, 2018		1,111,625		$	58.14		2.40	$	9,185

A summary of TSR performance stock option activity for fiscal year 2018 is presented below:

	Number of Shares (1)		Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2017 (2)		—	$	—
TSR performance options granted		497,500		73.77
TSR performance options canceled		—		—
TSR performance options exercised		—		—
Outstanding at March 31, 2018		497,500	$	73.77		5.63	$	—
Vested and exercisable at March 31, 2018		—	$	—		—	$	—

(1)

Number of shares is based on the target number of options under each TSR performance stock option.

(2)

The Company began granting TSR performance stock options to executive officers in the third quarter of fiscal year 2018.

Summary of Restricted Stock Unit Activity

A summary of restricted stock unit activity for fiscal year 2018 is presented below:

	Number of Restricted Stock Units			Weighted Average Grant Date Fair Value per Share
Outstanding at March 31, 2017		2,679,354		$	64.47
Awarded		1,166,362			72.89
Forfeited		(86,746	)		67.73
Released		(896,776	)		64.98
Outstanding at March 31, 2018		2,862,194		$	67.64
Vested and deferred at March 31, 2018		159,460		$	40.58