Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Tables)

v2.4.0.8
Stock Based Compensation (Tables)
 6 Months Ended
Jun. 30, 2014
Stock-Based Compensation Expense

The Company recognizes stock-based compensation in accordance with ASC 718, “Compensation—Stock Compensation.” Stock-based compensation expense, which consists of the compensation cost for employee stock options and the Company’s ESPP, and the value of options issued to non-employees for services rendered, was allocated to research and development and general and administrative in the unaudited consolidated statements of operations for the three and six months ended June 30, 2014 and 2013 as follows (in thousands):

 

 

Three Months Ended

June 30,

 

 

Six Months Ended

June 30,

 

 

2014

 

 

2013

 

 

2014

 

 

2013

 

Amortization of stock-based compensation:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Research and development

$

846

 

 

$

663

 

 

$

1,517

 

 

$

1,197

 

General and administrative

 

622

 

 

 

609

 

 

 

1,217

 

 

 

1,128

 

 

$

1,468

 

 

$

1,272

 

 

$

2,734

 

 

$

2,325

 

 

 
Weighted-Average Fair Value Valuation Assumptions

The fair value of employee stock options and employee purchase rights under the Company’s ESPP was estimated using the following weighted-average assumptions for the three and six months ended June 30, 2014 and 2013:

 

 

Three Months Ended

June 30,

 

 

Six Months Ended

June 30,

 

 

2014

 

 

2013

 

 

2014

 

 

2013

 

Employee Stock Options:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Risk-free interest rate

 

1.81

%

 

 

0.96

%

 

 

1.82

%

 

 

1.13

%

Expected term (in years)

 

5.97

 

 

 

5.47

 

 

 

5.97

 

 

 

5.97

 

Dividend yield

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Volatility

 

94

%

 

 

102

%

 

 

94

%

 

 

101

%

Weighted-average fair value of stock options granted

$

2.79

 

 

$

4.28

 

 

$

2.89

 

 

$

4.03

 

 

 

Three Months Ended

June 30,

 

 

Six Months Ended

June 30,

 

 

2014

 

 

2013

 

 

2014

 

 

2013

 

Employee Stock Purchase Plan (ESPP):

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Risk-free interest rate

 

0.18

%

 

 

0.20

%

 

 

0.18

%

 

 

0.20

%

Expected term (in years)

 

1.23

 

 

 

1.25

 

 

 

1.23

 

 

 

1.25

 

Dividend yield

 

—

 

 

 

—

 

 

 

—

 

 

 

—

 

Volatility

 

53

%

 

 

92

%

 

 

53

%

 

 

92

%

Weighted-average fair value of ESPP purchase rights

$

1.79

 

 

$

2.44

 

 

$

1.79

 

 

$

2.44

 

 
Stock Option Activity Under Equity Incentive Plan

The following table summarizes stock option activity under the Company’s equity incentive plans:

 

Options

 

Number of

Shares

 

 

Weighted-

Average

Exercise

Price

 

 

Weighted-

Average

Remaining

Contractual

Term

 

 

Aggregate

Intrinsic

Value

 

Outstanding at December 31, 2013

 

 

6,526,506

 

 

$

3.66

 

 

 

—

 

 

 

—

 

Granted

 

 

1,765,250

 

 

$

3.79

 

 

 

—

 

 

 

—

 

Exercised

 

 

(58,560

)

 

$

1.45

 

 

 

—

 

 

 

—

 

Forfeitures

 

 

(72,333

)

 

$

4.62

 

 

 

—

 

 

 

—

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Outstanding at June 30, 2014

 

 

8,160,863

 

 

$

3.69

 

 

 

7.67

 

 

 

8,434,466

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vested and expected to vest June 30, 2014

 

 

8,071,025

 

 

$

3.69

 

 

 

7.65

 

 

 

8,412,349

 

Exercisable at June 30, 2014

 

 

4,450,857

 

 

$

3.04

 

 

 

6.60

 

 

 

7,212,989