XML 31 R20.htm IDEA: XBRL DOCUMENT v3.8.0.1
Equity Incentive Plans and Stock-Based Compensation (Tables)
 9 Months Ended
Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Summary of Stock-based Compensation
A summary of our stock-based compensation expense is as follows (in thousands):
 
Three Months Ended September 30,
 
Nine Months Ended September 30,
 
2017
 
2016
 
2017
 
2016
Stock-based compensation by type of award:
 
 
 
 
 
 
 
Stock options
$
589

 
$
1,028

 
$
2,199

 
$
3,209

Stock awards
2,969

 
3,231

 
9,269

 
9,614

Employee stock purchase rights
987

 
329

 
2,356

 
246

 
$
4,545

 
$
4,588

 
$
13,824

 
$
13,069

 
 
 
 
 
 
 
 
Stock-based compensation by category of expense:
 
 
 
 
 
 
 
Cost of revenue
$
403

 
$
332

 
$
1,068

 
$
921

Sales and marketing
1,696

 
1,760

 
5,120

 
5,577

Research and development
1,537

 
1,730

 
5,024

 
4,251

General and administrative
909

 
766

 
2,612

 
2,320

 
$
4,545

 
$
4,588

 
$
13,824

 
$
13,069
Stock Options Valuation Assumptions
The fair value of the options was estimated as of the grant date using the Black-Scholes option-pricing model with the following assumptions:
 
Nine Months Ended September 30,
 
2017
 
2016
Expected term (in years)
4.7
 
4.9
Risk-free interest rate
1.74%
 
1.42%
Volatility
42%
 
49%
Dividend rate
—%
 
—%
Employee Stock Purchase Plan, Valuation Assumptions
The fair value of the employee stock purchase rights was estimated as of the grant date using the Black-Scholes option-pricing model with the following assumptions:
 
Nine Months Ended September 30,
 
2017
 
2016
Expected term (in years)
1.3
 
1.3
Risk-free interest rate
1.12%
 
0.65%
Volatility
38%
 
43%
Dividend rate
—%
 
—%
Summary of Activity under Stock Option Plans
The following tables summarize our stock option activities and related information:

 
Number of Shares (thousands)
 
Weighted-Average Exercise Price
 
Weighted-Average Remaining Contractual Term
(years)
 
Aggregate Intrinsic Value (thousands)
Outstanding as of December 31, 2016
7,868

 
$
4.82

 
 
 
 
Granted
135

 
$
8.42

 
 
 
 

Exercised
(1,272
)
 
$
3.35

 
 
 
 
Canceled (1)
(421
)
 
$
6.40

 
 
 
 

Outstanding as of September 30, 2017
6,310

 
$
5.09

 
5.5
 
$
17,668

Vested and exercisable as of September 30, 2017
5,152

 
$
5.01

 
4.9
 
$
15,004


 
 (1)
Includes 112,431 shares of canceled stock options from the 2008 Plan that became available for issuance under the 2014 Plan.
Stock Option Information
The following table provides information pertaining to our stock options (in thousands, except weighted-average fair value):
 
Nine Months Ended September 30,
 
2017
 
2016
Fair value of options granted
$
426

 
$
1,603

Weighted-average fair value of options granted
$
3.15

 
$
2.38

Intrinsic value of options exercised
$
7,014

 
$
5,003
Summary of Restricted Stock Units Activity
The following table summarizes our stock award activities and related information:
 
Number of Shares (thousands)
 
Weighted-Average Grant Date Fair Value
 
Weighted-Average Remaining Vesting Term
(years)
 
Aggregate Intrinsic Value (thousands)
Outstanding as of December 31, 2016
5,959

 
$
5.81

 
 
 
 
Granted
2,870

 
$
8.65

 
 
 
 
Released
(1,397
)
 
$
6.33

 
 
 
 
Canceled
(865
)
 
$
5.99

 
 
 
 
Outstanding as of September 30, 2017
6,567

 
$
6.92

 
1.6
 
$
49,650