STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

The following table summarizes activity under the Company’s stock option plans, including the 2012 and 2014 Inducement Plans and those suspended upon the adoption of the 2006 Share Incentive Plan, for the year ended December 31, 2016. All option grants presented in the table had exercise prices not less than the fair value of the underlying common stock on the grant date:

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Years	Aggregate Intrinsic Value ⁽¹⁾
Options outstanding as of December 31, 2015		10,322,903		$	44.50	5.6	$	630,949
Granted		847,450		$	84.31
Exercised		(2,129,090	)	$	29.23
Expired and forfeited		(185,055	)	$	84.78
Options outstanding as of December 31, 2016		8,856,208		$	51.13	5.4	$	304,356
Options expected to vest at December 31, 2016		1,753,013		$	84.38	8.3	$	10,707
Exercisable at December 31, 2016		7,103,016		$	42.92	4.6	$	293,646

(1)

The aggregate intrinsic value for outstanding options is calculated as the difference between the exercise price of the underlying awards and the quoted price of the Company’s common stock as of the last trading day for the respective year. The aggregate intrinsic value of options outstanding and exercisable includes options with an exercise price below $82.84, the closing price of the Company’s common stock on December 31, 2016.

Stock Option Valuation Assumptions

The assumptions used to estimate the per share fair value of stock options granted during the periods presented were as follows:

Years Ended December 31,

2016

2015

2014

Expected volatility

36 – 44%

36 – 45%

44 – 45%

Dividend yield

0.00%

Expected life

5.0 - 8.1 years

6.4 - 8.0 years

6.9 years

Risk-free interest rate

1.1 – 2.3%

1.5 – 2.2%

1.8 – 2.3%

Employee Stock Purchase Plan Valuation Assumptions

The assumptions used to estimate the per share fair value of stock purchase rights granted under the ESPP were as follows:

	Years Ended December 31,
	2016		2015		2014
Expected volatility	42 - 50%		36 - 38%		38 - 39%
Dividend yield		0.00%		0.00%		0.00%
Expected life	6-24 months		6-24 months		6-24 months
Risk-free interest rate	0.4 - 0.8%		0.1- 0.8%		0.1- 0.5%

Summary of Restricted Stock Unit Activity

A summary of RSU activity under the plan for the year ended December 31, 2016 as follows:

	Shares			Weighted Average Grant Date Fair Value		Weighted Average Remaining Years		Aggregate Intrinsic Value
Non-vested units as of December 31, 2015		2,147,209		$	93.89		2.8	$	224,942
Granted		1,321,224		$	84.18
Vested		(751,203	)	$	80.42
Forfeited		(272,264	)	$	94.52
Non-vested units as of December 31, 2016		2,444,966		$	92.70		1.4	$	202,541
Non-vested units expected to vest at December 31, 2016		2,444,966		$	92.70			$	202,541

Stock-Based Compensation Expense

Compensation expense included in the Company’s Consolidated Statements of Operations for all stock-based compensation arrangements was as follows:

	Years Ended December 31,
	2016		2015		2014
Cost of sales	$	9,121	$	6,836	$	6,076
Research and development		58,279		49,399		33,835
Selling, general and administrative		67,241		55,290		46,499
Total stock-based compensation expense	$	134,641	$	111,525	$	86,410