STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2016


	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2016	2015	2016	2015
Option Plan Shares
Risk-free interest rates	(1)	(1)	1.48% - 1.69%	1.5% - 1.92%
Expected term (in years)	(1)	(1)	6.25 - 6.74	6.25 - 6.6
Expected volatility	(1)	(1)	58.9% - 59.4%	67.1% - 73.2%
Dividend yield	(1)	(1)	0 %	0%
Weighted average fair value per share of options granted during the period	(1)	(1)	$ 3.17	$15.81
Market Measure-Based Shares
Risk-free interest rates	0.76 %	(2)	0.76% - 0.91%	(2)
Expected term (in years)	2.43	(2)	2.43 - 2.84	(2)
Expected volatility	79.6 %	(2)	68.3% - 79.6%	(2)
Dividend yield	0 %	(2)	0 %	(2)
Weighted average fair value per share of stock purchase rights granted during the period	$ 13.42	(2)	$ 3.77	(2)
ESPP Shares
Risk-free interest rates	(3)	(3)	0.41% - 0.8%	0.25% - 0.6%
Expected term (in years)	(3)	(3)	0.5 - 2	0.5 - 2
Expected volatility	(3)	(3)	70.1% - 92.7%	51.2% - 57.4%
Dividend yield	(3)	(3)	0 %	0%
Weighted average fair value per share of stock purchase rights granted during the period	(3)	(3)	$ 3.08	$ 7.48

(1)

The Company did not grant options under its 2010 Stock Plan during the period indicated.

(2)

The Company did not issue market measure-based shares during the respective period.

(3)

The Company did not issue stock purchase rights under its 2010 Employee Stock Purchase Plan during the respective period.

Summary of stock option activity under the Stock Plans


				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
		Exercise		Contractual	Intrinsic
Options	Shares	Price		Term (Years)	Value(1)
(Aggregate intrinsic value in thousands)
Outstanding, December 31, 2015	4,936,594	$	4.80	4.5
Granted	883,889		5.48
Exercised	(681,427)		1.57
Forfeited	(59,043)		9.75
Outstanding, September 30, 2016	5,080,013	$	5.29	4.8	$	69,009
Exercisable, September 30, 2016	3,838,961	$	3.81	3.5	$	57,076
Vested and expected to vest, September 30, 2016	5,014,789	$	5.24	4.8	$	68,340

(1)

The aggregate intrinsic value of options outstanding, exercisable and vested and expected to vest is calculated as the difference between the exercise price of the underlying options and the market price of the Company’s common stock for options that had exercise prices that were lower than the $18.57 market price of the Company’s common stock at September 30, 2016. The total intrinsic value of options exercised during the nine months ended September 30, 2016 and 2015 was $5.6 million and $2.0 million, respectively.

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


		Weighted
	Restricted	Average Grant
	Shares	Date Fair Value
Outstanding, January 1, 2016	3,444,694	$	14.19
Granted	3,912,879		6.16
Released	(723,808)		17.11
Forfeited	(644,464)		9.78
Outstanding, September 30, 2016	5,989,301	$	8.82