Note 3 - Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Share-Based Payment Arrangement, Cost by Plan [Table Text Block]

	Three Months Ended March 31,
	2022		2021
Cost of revenue	$	1,307	$	816
Research and development		8,401		6,165
Selling, general and administrative		30,103		21,602
Total stock-based compensation expense	$	39,811	$	28,583
Tax benefit related to stock-based compensation (1)	$	573	$	430

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

	Time-Based RSUs					PSUs and MPSUs					MSUs					Total
	Number of Shares			Weighted- Average Grant Date Fair Value Per Share		Number of Shares			Weighted- Average Grant Date Fair Value Per Share		Number of Shares			Weighted- Average Grant Date Fair Value Per Share		Number of Shares			Weighted- Average Grant Date Fair Value Per Share
Outstanding at January 1, 2022		125		$	235.82		1,166		$	222.78		1,218		$	44.59		2,509		$	136.87
Granted		27		$	394.67		442	(1)	$	371.40		120		$	270.15		589		$	351.82
Vested		(18	)	$	195.68		(263	)	$	146.71		(81	)	$	23.57		(362	)	$	121.58
Forfeited		(2	)	$	254.34		-		$	-		(2	)	$	169.32		(4	)	$	212.17
Outstanding at March 31, 2022		132		$	273.34		1,345		$	286.50		1,255		$	67.28		2,732		$	185.11

Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]

	Three Months Ended March 31,
	2022			2021
Expected term (in years)		0.5			0.5
Expected volatility		38.1	%		43.3	%
Risk-free interest rate		0.7	%		0.1	%
Dividend yield		0.6	%		0.6	%