STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Option Valuation Assumptions

The assumptions used to estimate the per share fair value of stock options granted under the 2017 Equity Incentive Plan and the 2006 Share Incentive Plan were as follows:

	Three Months Ended June 30,		Six Months Ended June 30,
	2017	2016	2017	2016
Expected volatility	38 – 40%	37 - 40%	38 – 40%	36 – 44%
Dividend yield	0.0%	0.0%	0.0%	0.0%
Expected life	5.0 – 6.6 years	5.1 - 6.8 years	5.0 – 6.6 years	5.1 – 8.1 years
Risk-free interest rate	1.8 – 1.9%	1.1 - 1.5%	1.8 – 2.2%	1.1 – 2.1%

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:

	Six Months Ended June 30,
	2017	2016
Expected volatility	31 - 42%	42 - 50%
Dividend yield	0.0%	0.0%
Expected life	6-24 months	6-24 months
Risk-free interest rate	1.0 - 1.3%	0.4 - 0.8%

Stock-Based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Cost of sales	$	2,510	$	2,289	$	4,796	$	3,851
R&D		14,647		14,814		26,141		28,521
SG&A		22,944		16,795		39,838		31,703
Total stock-based compensation expense	$	40,101	$	33,898	$	70,775	$	64,075