Stock-Based Compensation (Tables)

9 Months Ended

Dec. 31, 2021

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 each of the three and nine months ended December 31, 2021 and 2020:

	For the Three Months Ended December 31,				For the Nine Months Ended December 31,
		2021		2020		2021		2020
	(in thousands)
Cost of revenue	$	1,259	$	1,061	$	3,589	$	2,689
Research and development		2,278		1,922		6,681		5,069
Selling, general and administrative		8,846		9,873		30,470		25,961
	$	12,383	$	12,856	$	40,740	$	33,719

Summary of Stock Option Activity

The following table summarizes the stock option activity for the nine months ended December 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		711		$	141.87	5.46
Granted		66			289.01
Exercised		(155	)		56.98
Cancelled and expired		(14	)		314.28
Outstanding at end of period		608		$	175.36		5.72		113,080
Exercisable at end of period		462		$	147.90	4.81			99,031
Options vested and expected to vest at end of period		608		$	175.36		5.72		113,080

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 December 31,						For the Nine Months Ended December 31,
		2021			2020			2021			2020
Weighted average grant-date fair value	$	127.20		$	94.64		$	104.93		$	76.79
Valuation assumptions:
Risk-free interest rate		1.14	%		0.39	%		0.81	%		0.31	%
Expected option life (years)		5.57			4.17			4.28			4.22
Expected volatility		41.19	%		43.70	%		44.11	%		42.85	%

Restricted Stock Units

Summary of Restricted Stock Units Activity

The following table summarizes activity of restricted stock units for the nine months ended December 31, 2021:

				Weighted
				Average
	Number of			Grant Date
	Shares			Fair Value
	(in thousands)			(per share)
Restricted stock units at beginning of period		301		$	273.57
Granted (1)		171			289.73
Vested		(132	)		297.00
Forfeited		(30	)		275.27
Restricted stock units at end of period		310		$	274.15

(1) Includes 10 thousand performance-based awards granted due to greater than 100% target vesting.

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