Stock Award Plans and Stock-Based Compensation (Tables)

12 Months Ended

Mar. 31, 2021

Stock-Based Compensation Recognized

The following table summarizes stock-based compensation expense by financial statement line item in the Company’s consolidated statements of operations:

	Fiscal Years Ended March 31,
		2021		2020		2019
	(in $000's)
Cost of revenue	$	3,760	$	2,641	$	2,643
Research and development		6,941		5,534		9,312
Selling, general and administrative		36,305		31,606		42,539
	$	47,006	$	39,781	$	54,494

Components of Stock-Based Compensation

The components of stock-based compensation were as follows:

	Fiscal Years Ended March 31,
		2021		2020		2019
	(in $000's)
Restricted stock units	$	36,347	$	28,895	$	45,998
Stock options		8,982		9,006		7,445
Employee stock purchase plan		1,677		1,880		1,051
	$	47,006	$	39,781	$	54,494

Summary of Stock Option Activity

The following table summarizes stock option activity for the fiscal year ended March 31, 2021:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	(in thousands)			Price		Term (years)		(in thousands)
Outstanding at beginning of period		869		$	112.03		5.30
Granted		70			225.60
Exercised		(215	)		42.16
Cancelled and expired		(13	)		248.42
Outstanding at end of period		711		$	141.87		5.46	$	129,912
Exercisable at end of period		537		$	104.55		4.51	$	117,880
Options vested and expected to vest at end of period		711		$	141.87		5.46	$	129,912

Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted

The weighted average grant-date fair values and weighted average assumptions used in the calculation of fair value of options granted were as follows:

	Fiscal Years Ended March 31,
		2021			2020			2019
Valuation assumptions:
Weighted average grant-date fair value	$	77.82		$	93.05		$	141.47
Risk-free interest rate		0.32	%		1.97	%		2.91	%
Expected option life (years)		4.22			4.14			4.04
Expected volatility		42.9	%		42.3	%		42.8	%

Restricted Stock Units

Summary of Restricted Stock Units Activity

The following table summarizes restricted stock unit activity for the fiscal year ended March 31, 2021:

	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)			(per share)
Restricted stock units at beginning of period		320		$	263.92
Granted		230			254.78
Vested		(139	)		227.32
Forfeited		(109	)		266.57
Restricted stock units at end of period		301		$	273.57

Summary of Assumptions Used To Value Awards And Estimated Grant-Date Fair Value

The table below sets forth the assumptions used to value the awards and the estimated grant-date fair value:

Risk-free interest rate		0.2	%
Expected volatility		35.5	%
Dividend yield		—
Remaining performance period (years)	1.9 - 2.9
Estimated grant date fair value per share	$347.05 - $349.28
Target performance (number of shares)		30,881