Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Tables)

v3.8.0.1
Stockholders' Equity (Tables)
12 Months Ended
Dec. 31, 2017
Equity [Abstract]  
Schedule of Accounting for Share-Based Compensation
The following table summarizes stock-based compensation expense (in thousands):
 
December 31,
 
2017
 
2016
 
2015
Stock-based compensation expense as a component of:
 
 
 
 
 
Research and development expenses
$
14,235

 
$
8,836

 
$
4,080

General and administrative expenses
10,680

 
10,057

 
8,378

 
$
24,915

 
$
18,893

 
$
12,458

Schedule of Stock Option Plan Activity
Following is a summary of the Company’s stock option plan activity and related information:
 
 
Shares
 
Weighted
Average
Exercise
Price
 
Weighted
Average
Remaining
Contractual
Term in
Years
 
Aggregate
Intrinsic
Value
(In  thousands)
Balance at December 31, 2016
1,754,275

 
$
42.12

 
6.19
 
$
104,247

Granted
273,353

 
112.58

 
 
 
 
Exercised
(148,252
)
 
31.58

 
 
 
 
Forfeited
(3,044
)
 
79.74

 
 
 
 
Balance at December 31, 2017
1,876,332

 
53.17

 
5.77
 
157,340

Exercisable at December 31, 2017
1,431,245

 
40.08

 
4.95
 
138,616

Options vested and expected to vest as of December 31, 2017
1,876,332

 
$
53.17

 
5.77
 
$
157,340

Schedule of Stock Option Plan Activity by Exercise Price Range
Following is a further breakdown of the options outstanding as of December 31, 2017:
 
Range of exercise prices
Options
outstanding
 
Weighted
average
remaining  life
in years
 
Weighted average
exercise price
 
Options
exercisable
 
Weighted average
exercise price
$8.58 - $10.05
208,032

 
2.88
 
$
9.97

 
208,032

 
$
9.97

$10.12 - $12.81
71,850

 
3.95
 
11.44

 
71,850

 
11.44

$14.47 - $14.47
285,879

 
4.11
 
14.47

 
271,879

 
14.47

$16.14 - $17.88
72,777

 
1.16
 
16.32

 
72,777

 
16.32

$21.92 - $21.92
207,004

 
5.13
 
21.92

 
207,004

 
21.92

$32.00 - $56.26
226,287

 
6.72
 
50.50

 
160,301

 
48.49

$63.58 - $68.62
25,757

 
6.50
 
67.17

 
23,726

 
67.34

$74.42 - $74.42
216,118

 
6.11
 
74.42

 
206,828

 
74.42

$85.79 - $97.92
238,675

 
6.99
 
88.93

 
138,712

 
90.54

$100.38 - $141.61
323,953

 
9.12
 
112.75

 
70,136

 
106.78

$8.58 – $141.61
1,876,332

 
5.77
 
$
53.17


1,431,245

 
$
40.08

Schedule of Stock Option Weighted-Average Assumptions
The assumptions used for the specified reporting periods and the resulting estimates of weighted-average grant date fair value per share of options granted:

 
Year Ended December 31,
 
2017
 
2016
 
2015
 
Risk-free interest rate
2.0%-2.2%
 
1.3%-1.9%
 
1.7%-2.0%
 
Expected volatility
43%-47%
 
48%-50%
 
50%-58%
 
Expected term
6.5 to 6.8 years
 
6.6 to 6.7 years
 
6.5 years
 

Schedule of Restricted Stock Activity
The following is a summary of the Company’s restricted stock activity and related information:
 
 
Shares
 
Weighted-Average
Grant Date Fair
Value
Outstanding at December 31, 2016
308,700

 
$
86.61

Granted
73,799

 
99.53

Vested
(187,864
)
 
84.50

Forfeited
(61,341
)
 
97.78

Outstanding at December 31, 2017
133,294

 
$
91.60