Employee Stock-Based Compensation and Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Assumptions Used To Value Option Grants

The Company used the Black-Scholes model to estimate the fair value of the 2015 ESPP awards with the following weighted-average assumptions:

	Year Ended	Year Ended		Year Ended
	December 31, 2018	December 31, 2017		December 31, 2016
Expected volatility factor	0.26 - 0.29	0.27 - 0.29		0.27 - 0.41
Risk free interest rate	1.12% - 2.19%	0.60% - 1.12%		0.25% - 0.42%
Expected dividend yield	0% - 1.27%	0	%	0	%
Expected life (in years)	0.5	0.5		0.5

Detail Of The Total Stock-Based Compensation Recognized By Income Statement Classification

The detail of the total stock-based compensation recognized by income statement classification is as follows (in thousands):

Income Statement Classifications	2018		2017		2016
Cost of subscription, support and services	$	7,979	$	4,281	$	2,179
Research and development	66,154		47,291		38,578
Sales, marketing and services	72,406		55,173		48,514
General and administrative	57,080		58,375		63,468
Total	$	203,619	$	165,120	$	152,739

Schedule of Nonvested Stock Unit Activity

The following table summarizes the Company's non-vested stock unit activity for the year ended December 31, 2018:

	Number of Shares		Weighted- Average Fair Value at Grant Date
Non-vested stock units at December 31, 2017	4,622,546		$	82.83
Granted	3,903,225		92.20
Vested	(2,076,052	)	71.92
Forfeited	(596,218	)	74.07
Non-vested stock units at December 31, 2018	5,853,501		88.79

Non-vested stock

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Assumptions Used To Value Option Grants

The grant date fair value of the non-vested performance stock unit awards was determined through the use of a Monte Carlo simulation model, which utilized multiple input variables that determined the probability of satisfying the market condition requirements applicable to each award as follows:

	March 2017 Grant (Modified)		March 2017 Grant		March 2016 Grant		January 2016 Grant
Expected volatility factor	0.16 - 0.32		0.27 - 0.32		0.29 - 0.39		0.29 - 0.37
Risk free interest rate	2.67	%	1.48	%	0.91	%	1.10	%
Expected dividend yield	0	%	0	%	0	%	0	%