Stock-based Compensation Expense (Tables)

3 Months Ended

Apr. 30, 2016

A summary of restricted stock unit activity for the three months ended April 30, 2016 is as follows:



	Unvested Restricted Stock Units		Weighted average grant date fair value per share
	(in thousands)
Unvested restricted stock units at January 31, 2016	7,739.6		$	51.80
Granted	1,015.9		57.68
Vested	(863.8	)	56.48
Canceled/Forfeited	(311.3	)	51.87
Performance Adjustment (1)	(29.7	)	63.81
Unvested restricted stock units at April 30, 2016	7,550.7		$	52.26

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(1)	Based on Autodesk's financial results and relative total stockholder return for the fiscal 2016 performance period. The performance stock units were attained at rates ranging from 86.1% to 98.0% of the target award.

The following table summarizes stock-based compensation expense for the three months ended April 30, 2016 and 2015, respectively, as follows:



	Three Months Ended April 30,
	2016		2015
Cost of subscription	$	1.7	$	1.4
Cost of license and other revenue	1.8		1.5
Marketing and sales	23.6		21.7
Research and development	20.9		17.6
General and administrative	8.9		8.0
Stock-based compensation expense related to stock awards and ESPP purchases	56.9		50.2
Tax benefit	—		(14.0		)
Stock-based compensation expense related to stock awards and ESPP purchases, net of tax	$	56.9	$	36.2

Autodesk uses the following assumptions to estimate the fair value of stock-based awards:



	Three Months Ended April 30, 2016		Three Months Ended April 30, 2015
	Performance Stock Unit	ESPP	Performance Stock Unit	ESPP
Range of expected volatilities	38.4 - 38.6%	35.0 - 40.2%	27.3%	27.7 - 28.2%
Range of expected lives (in years)	N/A	0.5 - 2.0	N/A	0.5 - 2.0
Expected dividends	—%	—%	—%	—%
Range of risk-free interest rates	0.6 - 0.7%	0.5 - 0.9%	0.2%	0.1 - 0.6%