| Summary of stock option activity |
A summary of stock option activity for the year ended December 31, 2014 is as follows (in thousands, except for per share and weighted-average contractual life amounts):
|
|
|
Shares
|
|
Weighted-
Average
Exercise
Price (in
dollars per
share)
|
|
Weighted-
Average
Contractual
Life
(In Years)
|
|
Aggregate
Intrinsic
Value
|
|
|
Options outstanding at December 31, 2013
|
|
|
1,667
|
|
$
|
7.05
|
|
|
|
|
|
|
|
|
Granted
|
|
|
2,785
|
|
|
15.20
|
|
|
|
|
|
|
|
|
Exercised
|
|
|
(49
|
)
|
|
3.45
|
|
|
|
|
|
|
|
|
Cancelled
|
|
|
(1,182
|
)
|
|
8.63
|
|
|
|
|
|
|
|
|
Expired
|
|
|
(1
|
)
|
|
3.42
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Options outstanding at December 31, 2014
|
|
|
3,220
|
|
$
|
13.58
|
|
|
8.57
|
|
$
|
81,584
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Options exercisable at December 31, 2014
|
|
|
1,323
|
|
$
|
9.98
|
|
|
7.27
|
|
$
|
38,266
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Options vested or expected to vest at December 31, 2014
|
|
|
3,114
|
|
$
|
13.49
|
|
|
8.54
|
|
$
|
79,158
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Summary of stock-based compensation expense by financial statement line |
The following table summarizes stock-based compensation expense by financial statement line (in thousands):
|
|
|
Years Ended December 31,
|
|
|
|
|
2014
|
|
2013
|
|
2012
|
|
|
Research and development
|
|
$
|
1,953
|
|
$
|
302
|
|
$
|
338
|
|
|
General and administrative
|
|
|
5,117
|
|
|
1,206
|
|
|
1,457
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Share-based compensation expense included in operating expenses
|
|
$
|
7,070
|
|
$
|
1,508
|
|
$
|
1,795
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|