v3.20.4
Stockholders' Equity (Tables)
 12 Months Ended
Dec. 31, 2020
Summary of Stock Option Award Activity The following table summarizes the stock option award activity under the Stock Plans during the year ended December 31, 2020:

 

 

Class A

Number

of Shares

 

 

Class B

Number

of Shares

 

 

Weighted-

Average

Exercise

Price

 

 

Weighted-

Average

Remaining

Contractual

Term

(in years)

 

 

Aggregate

Intrinsic

Value(1)

 

 

 

(in thousands, except per share data)

 

Outstanding at December 31, 2019

 

 

8,712

 

 

 

1,550

 

 

$

9.00

 

 

 

5.59

 

 

$

75,460

 

Granted

 

 

90

 

 

 

—

 

 

$

24.95

 

 

 

—

 

 

$

—

 

Exercised

 

 

(3,824

)

 

 

(754

)

 

$

7.47

 

 

 

—

 

 

$

—

 

Forfeited

 

 

(150

)

 

 

—

 

 

$

13.78

 

 

 

—

 

 

$

—

 

Outstanding at December 31, 2020

 

 

4,828

 

 

 

796

 

 

$

10.37

 

 

 

5.20

 

 

$

223,230

 

Exercisable at December 31, 2020

 

 

3,466

 

 

 

796

 

 

$

9.35

 

 

 

4.37

 

 

$

173,581

 

Vested and expected to vest at December 31, 2020

 

 

4,761

 

 

 

796

 

 

$

10.34

 

 

 

5.17

 

 

$

220,777

 

 

(1)

The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying stock option awards and the closing market price of our Class A common stock as of December 31, 2020 and December 31, 2019, respectively.
Summary of Total Stock-based Compensation Expense

Total stock-based compensation expense by function was as follows:

 

 

Year Ended December 31,

 

 

2020

 

 

2019

 

 

2018

 

 

(in thousands)

 

Cost of revenue

$

9,367

 

 

$

6,365

 

 

$

4,393

 

Research and development

 

533,272

 

 

 

464,639

 

 

 

340,533

 

Sales and marketing

 

108,270

 

 

 

93,355

 

 

 

84,059

 

General and administrative

 

119,273

 

 

 

121,654

 

 

 

109,226

 

Total

$

770,182

 

 

$

686,013

 

 

$

538,211

 

 
Restricted Stock Units and Restricted Stock Awards  
Summary of RSU and RSA Award Activity

The following table summarizes the RSU and RSA activity during the year ended December 31, 2020:

 

 

 

Class A

Outstanding

 

 

Weighted-

Average

Grant Date

Fair Value

per RSU

 

 

 

(in thousands, except per share data)

 

Unvested at December 31, 2019

 

 

148,797

 

 

$

12.39

 

Granted

 

 

61,337

 

 

$

19.67

 

Vested

 

 

(71,301

)

 

$

13.60

 

Forfeited

 

 

(7,661

)

 

$

13.19

 

Unvested at December 31, 2020

 

 

131,172

 

 

$

15.10