Note 8 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

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

	Year Ended December 31,
	2021		2020		2019
Cost of revenue	$	3,543	$	2,592	$	2,409
Research and development		26,030		20,033		19,584
Selling, general and administrative		93,906		62,926		56,706
Total stock-based compensation expense	$	123,479	$	85,551	$	78,699
Tax benefit related to stock-based compensation (1)	$	1,760	$	1,855	$	2,754

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, 2019		240		$	95.38		2,174		$	61.61		2,219		$	35.69		4,633		$	50.94
Granted		52		$	141.32		512	(1)	$	99.88		-		$	-		564		$	103.68
Vested		(103	)	$	81.53		(656	)	$	53.72		(324	)	$	23.57		(1,083	)	$	47.34
Forfeited		(9	)	$	117.31		(43	)	$	42.72		(9	)	$	68.48		(61	)	$	57.01
Outstanding at December 31, 2019		180		$	115.45		1,987		$	74.50		1,886		$	37.63		4,053		$	59.16
Granted		76		$	189.28		627	(1)	$	173.40		-		$	-		703		$	175.12
Vested		(86	)	$	110.67		(1,213	)	$	59.03		(324	)	$	23.57		(1,623	)	$	54.70
Forfeited		(9	)	$	138.34		(11	)	$	84.48		(8	)	$	68.48		(28	)	$	96.35
Outstanding at December 31, 2020		161		$	151.62		1,390		$	132.60		1,554		$	40.40		3,105		$	87.42
Granted		46		$	384.33		365	(1)	$	354.12		-		$	-		411		$	357.49
Vested		(71	)	$	144.46		(577	)	$	91.50		(324	)	$	23.57		(972	)	$	72.69
Forfeited		(11	)	$	207.04		(12	)	$	103.84		(12	)	$	68.48		(35	)	$	124.50
Outstanding at December 31, 2021		125		$	235.82		1,166		$	222.78		1,218		$	44.59		2,509		$	136.87

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

	Year Ended December 31,
	2021			2020			2019
Expected term (in years)		0.5			0.5			0.5
Expected volatility		43.2	%		48.9	%		37.0	%
Risk-free interest rate		0.1	%		0.8	%		2.2	%
Dividend yield		0.6	%		0.9	%		1.1	%