Employee Benefit Plans

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Employee Benefit Plans

Note 11. Employee Benefit Plans

Equity Incentive Plans

The Company has stock-based compensation plans pursuant to which it has granted stock options, restricted stock units (“RSUs”), and performance share awards (“PSAs”). The Company also maintains its 2008 Employee Stock Purchase Plan (the “ESPP”) for all eligible employees. As of June 30, 2021, 10.0 million and 10.1 million shares were available for future issuance under the Company's 2015 Equity Incentive Plan (the "2015 Plan") and the ESPP, respectively. In connection with past acquisitions, the Company has also assumed or substituted stock options, RSUs, restricted stock awards ("RSAs"), and PSAs.

RSU, RSA and PSA Activities

The Company’s RSU, RSA and PSA activity and related information as of and for the six months ended June 30, 2021 were as follows (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, 2020	19.9	$	23.05
Granted(*)	3.3	23.95
Awards assumed upon the acquisition of Apstra	2.2	25.49
Vested	(4.4)	24.47
Canceled	(1.4)	24.25
Balance as of June 30, 2021	19.6	$	23.08	1.4	$	536.1

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(*)    Includes 1.3 million service-based, 1.5 million performance-based, and 0.5 million market-based RSUs and PSAs, as applicable. The number of shares subject to performance-based and market-based conditions represents the aggregate maximum number of shares that may be issued pursuant to the award over its full term. The grant date fair value of RSUs and PSAs was reduced by the present value of dividends expected to be paid on the underlying shares of common stock during the requisite and derived service period as these awards are not entitled to receive dividends until vested.

Employee Stock Purchase Plan

The following table summarizes employee stock purchases through the ESPP (in millions, except per share amounts):

	Six Months Ended June 30,
	2021		2020
Shares purchased	1.4		1.4
Average exercise price per share	$	19.75	$	19.50

Share-Based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Cost of revenues - Product	$	1.0	$	1.1	$	2.3	$	2.5
Cost of revenues - Service	3.9		3.4		8.4		7.6
Research and development	20.1		19.0		44.3		34.2
Sales and marketing	14.9		13.2		31.4		27.0
General and administrative	10.6		7.3		21.6		14.7
Total	$	50.5	$	44.0	$	108.0	$	86.0

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Stock options	$	2.5	$	1.8	$	5.2	$	3.7
RSUs, RSAs, and PSAs	44.6		37.3		94.5		72.2
ESPP	3.4		4.9		8.3		10.1
Total	$	50.5	$	44.0	$	108.0	$	86.0

As of June 30, 2021, the total unrecognized compensation cost related to unvested share-based awards was $303.7 million to be recognized over a weighted-average period of 1.89 years.