Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

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

	Three Months Ended				Nine Months Ended
	September 30, 2017		September 30, 2016		September 30, 2017		September 30, 2016
Expected volatility factor	0.27 - 0.29		0.27 - 0.41		0.27 - 0.29		0.27 - 0.41
Risk free interest rate	0.60% - 1.12%		0.35% - 0.42%		0.60% - 1.12%		0.25% - 0.42%
Expected dividend yield	0	%	0	%	0	%	0	%
Expected life (in years)	0.5		0.5		0.5		0.5

Schedule of 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):

	Three Months Ended				Nine Months Ended
Income Statement Classifications	September 30, 2017		September 30, 2016		September 30, 2017		September 30, 2016
Cost of services and maintenance revenues	$	1,132	$	590	$	2,539	$	1,626
Research and development	14,365		10,501		35,691		27,945
Sales, marketing and services	16,063		13,405		42,388		36,909
General and administrative	20,172		16,347		46,601		48,791
Total	$	51,732	$	40,843	$	127,219	$	115,271

Schedule of Assumptions Used to Value Nonvested Share 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		March 2016 Grant		January 2016 Grant
Expected volatility factor	0.27-0.32		0.29 - 0.39		0.29 - 0.37
Risk free interest rate	1.48	%	0.91	%	1.10	%
Expected dividend yield	0	%	0	%	0	%