Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Tables)

v3.6.0.2
Stock-Based Compensation (Tables)
12 Months Ended
Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Stock-Based Compensation Expense

The following table shows total stock-based compensation expense recognized in the accompanying consolidated statements of operations (in thousands):

 

 

 

Year Ended December 31,

 

 

 

2016

 

 

2015

 

 

2014

 

Research and development

 

$

6,463

 

 

$

6,444

 

 

$

5,064

 

General and administrative

 

 

8,594

 

 

 

5,286

 

 

 

4,136

 

Total stock-based compensation expense

 

$

15,057

 

 

$

11,730

 

 

$

9,200

 

 

Assumptions Used for Estimating Fair Value of Employee Stock Options

The assumptions used for estimating the fair value of the employee stock options are as follows:

 

 

 

Year Ended December 31,

 

 

 

2016

 

 

2015

 

 

2014

 

Risk-free interest rate

 

1.13-1.61%

 

 

1.46-1.58%

 

 

1.60-1.70%

 

Expected life of option (in years)

 

5.28-5.29

 

 

5.25-5.31

 

 

5.28-5.33

 

Expected dividend yield of stock

 

 

0

%

 

 

0

%

 

 

0

%

Expected volatility

 

0.68-0.70

 

 

0.66-0.67

 

 

0.66-0.69

 

 

Weighted-Average Assumptions Used for Estimating Fair Value of ESPP Purchase Rights

The weighted–average assumptions used for estimating the fair value of the ESPP purchase rights are as follows:

 

 

Year Ended December 31,

 

 

 

2016

 

 

2015

 

 

2014

 

Risk-free interest rate

 

0.41-0.80%

 

 

0.06-0.33%

 

 

0.05-0.30%

 

Expected life of option (in years)

 

0.5-2.0

 

 

0.5-2.0

 

 

0.5-2.0

 

Expected dividend yield of stock

 

 

0

%

 

 

0

%

 

 

0

%

Expected volatility

 

0.71-0.76

 

 

0.55-0.70

 

 

0.52-0.75