STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

The fair value of each option is based on the assumptions in the following table:


	Three Months Ended September 30,			Nine Months Ended September 30,
	2020	2019	2020	2019
Option Plan Shares
Risk-free interest rates	(1)	(1)	0.11% - 1.47%	2.54% - 2.59%
Expected term (in years)	(1)	(1)	0.25 - 6.15	6.28
Expected volatility	(1)	(1)	44.19% - 77.51%	64.95% - 65.00%
Dividend yield	(1)	(1)	—%	—%
Weighted average fair value per share of options granted during the period	(1)	(1)	$58.57	$57.11
ESPP Shares
Risk-free interest rates	(2)	(2)	0.12% - 0.2%	2.31% - 2.44%
Expected term (in years)	(2)	(2)	0.5 - 2	0.5 - 2
Expected volatility	(2)	(2)	63.7% - 89.0%	55.0% - 58.0%
Dividend yield	(2)	(2)	—%	—%
Weighted average fair value per share of stock purchase rights granted during the period	(2)	(2)	$30.60	$35.91

______________

(1)The Company did not grant options under its 2010 Omnibus Long-Term Incentive Plan or 2019 Omnibus Long-Term Incentive Plan during the period indicated.

(2)The Company did not issue stock purchase rights under its 2010 Employee Stock Purchase Plan during the period indicated.

Summary of stock option activity under the Stock Plans

A summary of stock option activity under the Stock Plans during the nine months ended September 30, 2020 is as follows:


Options	Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term(Years)	Aggregate Intrinsic Value(1)
(Aggregate intrinsic value in thousands)
Outstanding, January 1, 2020	2,700,293	$	34.01	6.7
Granted	309,143	97.66
Exercised	(509,335)	30.34
Forfeited	(71,364)	82.76
Outstanding, September 30, 2020	2,428,737	$	41.45	6.3	$	146,939
Exercisable, September 30, 2020	1,577,785	$	26.96	5.4	$	118,314

______________

(1)The total intrinsic value of options exercised during the nine months ended September 30, 2020 and 2019 was $29.0 million and $41.7 million, respectively, determined as of the date of exercise.

Summary of restricted stock and restricted stock unit activity under the Stock Plans

A summary of restricted stock and restricted stock unit activity under the Stock Plans during the nine months ended September 30, 2020 is as follows:


	Restricted Shares and RSUs	Weighted Average Grant Date Fair Value
Outstanding, January 1, 2020	4,384,005	$	63.41
Granted	2,166,913	90.94
Released	(1,615,545)	48.97
Forfeited	(280,899)	80.67
Outstanding, September 30, 2020	4,654,474	$	80.10