Stock-Based Compensation (Tables)

3 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Recognized

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

	For the Three Months Ended June 30,
		2021		2020
	(in $000's)
Cost of  revenue	$	1,030	$	705
Research and development		2,109		1,442
Selling, general and administrative		9,469		7,151
	$	12,608	$	9,298

Summary of Stock Option Activity

The following table summarizes the stock option activity for the three months ended June 30, 2021:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	(in thousands)			Price		Term (years)		(in thousands)
Outstanding at beginning of period		711		$	141.87		5.46
Granted		60			285.52
Exercised		(56	)		38.02
Cancelled and expired		(3	)		259.61
Outstanding at end of period		712		$	161.56		5.77	$	111,794
Exercisable at end of period		562		$	135.54		4.89	$	103,757
Options vested and expected to vest at end of period		712		$	161.56		5.77	$	111,794

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 was as follows: 

	For the Three Months Ended June 30,
		2021			2020
Weighted average grant-date fair value	$	103.03		$	75.75
Valuation assumptions:
Risk-free interest rate		0.79	%		0.31	%
Expected option life (years)		4.20			4.22
Expected volatility		44.28	%		42.80	%

Restricted Stock Units

Summary of Restricted Stock Units Activity

The following table summarizes activity of restricted stock units for the three months ended June 30, 2021:

	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)			(per share)
Restricted stock units at beginning of period		301		$	273.57
Granted		146			286.57
Vested		(84	)		303.33
Forfeited		(7	)		268.73
Restricted stock units at end of period		356		$	272.06

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:

	May 2021			May 2020
Risk-free interest rate		0.3	%		0.2	%
Expected volatility		44.8	%		35.5	%
Dividend yield		—			—
Remaining performance period (years)		2.8		1.9 - 2.9
Estimated fair value per share		$292.40		$347.05 - $349.28
Target performance (number of shares)		25,172			30,881