XML 109 R30.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Stock-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Stock-Based Compensation Expense
We recognize total stock-based compensation expense in our Condensed Consolidated Statements of Operations as follows (in thousands):
 
Year Ended December 31,
 
2019
 
2018
 
2017
Cost of goods sold
$
4,294

 
$
4,629

 
$
2,333

Research and development
63,224

 
56,193

 
21,252

General and administrative
32,277

 
27,279

 
13,030

Total stock-based compensation
$
99,795

 
$
88,101

 
$
36,615
Black-Scholes Option-Pricing Model Assumptions Used to Calculate Fair Value of Employee Stock Options
The following table lists the Black-Scholes option-pricing model assumptions used to calculate the fair value of employee and director stock options, as well as the resulting grant-date fair value:
 
Year Ended December 31,
 
2019
 
2018
 
2017
Average risk-free interest rate
1.8
%
 
2.8
%
 
2.0
%
Dividend yield
0.0
%
 
0.0
%
 
0.0
%
Average volatility factor
62.2
%
 
61.0
%
 
54.2
%
Weighted-average expected life
5.6 years

 
5.1 years

 
5.3 years

Weighted-average grant-date fair value of options granted
$
12.25

 
$
29.86

 
$
20.08
Stock Option Activity Under Equity Incentive Plans
The table below presents a summary of stock option activity under our equity incentive plans (in thousands, except for price per share and contractual life information):
 
Number
of
Shares
 
Weighted-
Average
Exercise
Price
per Share
 
Weighted-
Average
Remaining
Contractual
Life
(in Years)
 
Aggregate
Intrinsic
Value(1)
Outstanding at December 31, 2018
15,930

 
$
26.18

 
 
 
 
Options granted
1,842

 
21.86

 
 
 
 
Options exercised
(1,629
)
 
11.68

 
 
 
 
Options forfeited & canceled
(1,258
)
 
49.91

 
 
 
 
Outstanding at December 31, 2019
14,885

 
$
25.23

 
4.31
 
$
73,134

 
 
 
 
 
 
 
 
Exercisable at December 31, 2019
9,938

 
20.79

 
3.14
 
$
66,707

_______________________________________________________________
(1)
Aggregate intrinsic value represents the difference between the exercise price of the option and the closing market price of our common stock on December 31, 2019.
Restricted Stock Unit Award Activity
A summary of RSU award activity is as follows (in thousands except for per share amounts):
 
Units Issued
 
Weighted-
Average
Grant
Date Fair
Value
 
Aggregate
Intrinsic
Value(1)
Balance at December 31, 2018
3,320

 
$
41.57

 
 
Granted
3,189

 
23.32

 
 
Vested and released
(1,159
)
 
36.33

 
 
Forfeited and canceled
(415
)
 
43.19

 
 
Balance at December 31, 2019
4,935

 
$
30.85

 
$
106,506