Employee Benefit Plans

Share-Based Compensation Plans

The Company’s share-based compensation plans include the 2006 Equity Incentive Plan (the “2006 Plan”), the 2000 Nonstatutory Stock Option Plan (the “2000 Plan”), the Amended and Restated 1996 Stock Plan (the “1996 Plan”), various equity incentive plans assumed through acquisitions, and the 2008 Employee Stock Purchase Plan (the "2008 Purchase Plan"). Under these plans, the Company has granted (or in the case of acquired plans assumed) stock options, restricted stock units ("RSUs"), restricted stock awards ("RSAs"), and performance share awards ("PSAs").

The 2006 Plan was adopted and approved by the Company’s stockholders in May 2006. To date, the Company's stockholders have approved a share reserve of 149.5 million shares of common stock plus the addition of any shares subject to options under the 2000 Plan and the 1996 Plan that were outstanding as of May 18, 2006, and that subsequently expire unexercised, up to a maximum of an additional 75.0 million shares. As of March 31, 2013, the 2006 Plan had 52.5 million shares subject to currently outstanding equity awards and 43.8 million shares available for future issuance.

The 2008 Purchase Plan was adopted in May 2008. To date, the Company's stockholders have approved a share reserve of 19.0 million shares of the Company's common stock for issuance under this plan. The 2008 Purchase Plan permits eligible employees to acquire shares of the Company’s common stock at a 15% discount to the offering price (as determined in the 2008 Purchase Plan) through periodic payroll deductions of up to 10% of base compensation, subject to individual purchase limits of 6,000 shares in any twelve-month period or $25,000 worth of stock, determined at the fair market value of the shares at the time the stock purchase option is granted, in one calendar year. As of March 31, 2013, approximately 11.4 million shares have been issued and 7.6 million shares remain available for future issuance under the 2008 Purchase Plan.

In connection with certain past acquisitions, the Company assumed stock options, RSU, and RSA awards under the assumed stock plans of the acquired companies and exchanged the assumed awards for Juniper Networks' stock options, RSUs, and RSAs, respectively. No new stock options, RSUs, and RSAs can be granted under these plans. As of March 31, 2013, stock options, RSUs and RSAs representing approximately 6.6 million shares of common stock were outstanding under all awards assumed through the Company's acquisitions.

Stock Option Activities

The following table summarizes the Company’s stock option activity and related information as of and for the three months ended March 31, 2013 (in millions, except for per share amounts and years):



	Outstanding Options
	Number of Shares		Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value
Balance as of December 31, 2012	34.1		$	24.13
Options granted	—		—
Options canceled	(0.4	)	31.35
Options exercised	(2.3	)	16.17
Options expired	(1.4	)	27.73
Balance as of March 31, 2013	30.0		$	24.46	3.1	$	35.8

As of March 31, 2013:
Vested and expected-to-vest options	29.2		$	24.50	3.0	$	32.5
Exercisable options	24.5		$	24.33	2.4	$	18.8

Aggregate intrinsic value represents the difference between the Company’s closing stock price on the last trading day of the period, which was $18.54 per share as of March 31, 2013, and the exercise price multiplied by the number of related options. The pre-tax intrinsic value of options exercised, representing the difference between the fair market value of the Company’s common stock on the date of the exercise and the exercise price of each option, was $11.9 million for the three months ended March 31, 2013.

Restricted Stock Unit, Restricted Stock Award, and Performance Share Award Activities

The following table summarizes the Company’s RSU, RSA, and PSA activity and related information as of and for the three months ended March 31, 2013 (in millions, except per share amounts and years):



	Outstanding RSUs, RSAs, and PSAs
	Number of Shares		Weighted Average Grant-Date Fair Value per Share		Weighted Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value
Balance as of December 31, 2012	26.8		$	27.76
RSUs granted	7.7		20.41
PSAs granted^(*)	2.0		21.36
RSUs vested	(3.8	)	28.80
PSAs vested	(1.0	)	28.26
RSAs vested	(0.2	)	19.59
RSUs canceled	(0.7	)	24.20
PSAs canceled	(1.8	)	29.05
Balance as of March 31, 2013	29.0		$	25.28	1.7	$	538.4

As of March 31, 2013:
Vested and expected-to-vest RSUs, RSAs, and PSAs	24.9		$	23.95	1.6	$	461.3

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^(*)

The number of shares subject to PSAs granted represents the aggregate maximum number of shares that may be issued pursuant to the award over its full term. The aggregate number of shares subject to these PSAs that would be issued if performance goals determined by the Compensation Committee are achieved at target is 1.0 million shares. Depending on achievement of such performance goals, the range of shares that could be issued under these awards is 0 to 2.0 million shares.

Employee Stock Purchase Plan ("ESPP")

The Company's 2008 Purchase Plan is implemented in a series of offering periods, each six months in duration, or a shorter period as determined by the Board. Employees purchased approximately 1.9 million and 1.7 million shares of common stock through the 2008 Purchase Plan at an average per share price of $15.05 and $17.79 for the three months ended March 31, 2013 and March 31, 2012, respectively.

Share-Based Compensation Expense

The weighted-average assumptions used and the resulting estimates of fair value for stock options and ESPP were as follows:



	Three Months Ended March 31,
	2013	2012
Stock Options:
Volatility	—	46%
Risk-free interest rate	—	0.8%
Expected life (years)	—	4.2
Dividend yield	—	—
Weighted-average fair value per share	—	$8.51

ESPP:
Volatility	36%	51%
Risk-free interest rate	0.1%	0.1%
Expected life (years)	0.5	0.5
Dividend yield	—	—
Weighted-average fair value per share	$5.63	$6.38

Share-based compensation expense associated with stock options, ESPP, RSUs, RSAs, and PSAs was recorded in the following cost and expense categories in the Company's Condensed Consolidated Statements of Operations (in millions):



	Three Months Ended March 31,
	2013		2012
Cost of revenues - Product	$	0.9	$	1.0
Cost of revenues - Service	4.6		5.3
Research and development	23.6		25.8
Sales and marketing	14.5		21.9
General and administrative	6.3		11.0
Total	$	49.9	$	65.0

The following table summarizes share-based compensation expense by award type (in millions):



	Three Months Ended March 31,
	2013		2012
Stock options	$	9.5	$	17.7
RSUs and PSAs	33.7		41.8
RSAs	3.3		—
ESPP	3.4		5.5
Total	$	49.9	$	65.0

The following table presents unrecognized compensation cost, adjusted for estimated forfeitures, recognized over a weighted-average period related to unvested stock options, RSUs, PSAs, and RSAs as of March 31, 2013 (in millions, except years):



	Unrecognized Compensation Cost		Weighted Average Period (In Years)
Stock options	$	59.0	2.3
RSUs and PSAs	342.7		2.2
RSAs	$	65.2	3.2