|
Compensation and Other Benefit Plans (Tables)
|
12 Months Ended |
|
Dec. 31, 2014
|
| Compensation and Other Benefit Plans [Abstract] |
|
| Stock option activity |
The following table summarizes the Company’s stock option activity:
| |
|
2014 |
|
|
2013 |
|
|
2012 |
|
| |
|
Number of
Shares
|
|
|
Weighted
Average
Exercise
Price
|
|
|
Number of
Shares
|
|
|
Weighted
Average
Exercise
Price
|
|
|
Number of
Shares
|
|
|
Weighted
Average
Exercise
Price
|
|
Outstanding at beginning of year |
|
|
7,216,041 |
|
|
$ |
8.42 |
|
|
|
6,788,383 |
|
|
$ |
8.99 |
|
|
|
5,053,435 |
|
|
$ |
12.55 |
|
Granted |
|
|
1,891,989 |
|
|
|
6.69 |
|
|
|
1,168,203 |
|
|
|
3.13 |
|
|
|
2,351,445 |
|
|
|
2.59 |
|
Exercised |
|
|
(915,911 |
) |
|
|
3.91 |
|
|
|
(589,355 |
) |
|
|
2.26 |
|
|
|
(90,252 |
) |
|
|
1.68 |
|
Forfeited, expired or cancelled |
|
|
(489,810 |
) |
|
|
14.36 |
|
|
|
(151,190 |
) |
|
|
17.46 |
|
|
|
(526,245 |
) |
|
|
15.84 |
|
Outstanding at end of year |
|
|
7,702,309 |
|
|
|
8.15 |
|
|
|
7,216,041 |
|
|
|
8.42 |
|
|
|
6,788,383 |
|
|
|
8.99 |
|
Exercisable at end of year |
|
|
4,908,925 |
|
|
|
9.98 |
|
|
|
4,814,926 |
|
|
|
11.14 |
|
|
|
4,276,834 |
|
|
|
12.42 |
|
Weighted average grant date fair value |
|
|
|
|
|
$ |
4.49 |
|
|
|
|
|
|
$ |
2.27 |
|
|
|
|
|
|
$ |
1.89 |
|
|
| Unvested RSU activity |
Unvested RSU activity for the year ended December 31, 2014 is summarized below:
| |
|
|
|
|
Weighted |
|
| |
|
Number of |
|
|
Average Grant |
|
| |
|
Shares |
|
|
Date Fair Value |
|
| |
|
|
|
|
|
|
Unvested awards at December 31, 2013 |
|
|
1,738,037 |
|
|
$ |
2.73 |
|
Granted |
|
|
1,506,194 |
|
|
|
7.03 |
|
Vested |
|
|
(1,099,701 |
) |
|
|
3.51 |
|
Forfeited |
|
|
(190,651 |
) |
|
|
4.22 |
|
Unvested awards at December 31, 2014 |
|
|
1,953,879 |
|
|
|
5.46 |
|
|
| Weighted average assumptions |
The fair value of stock option awards was estimated using the Black-Scholes model with the following weighted average assumptions for the years ended December 31, 2014, 2013, and 2012:
| |
|
Year Ended December 31, |
|
| |
|
2014 |
|
|
2013 |
|
|
2012 |
|
Dividend yield |
|
|
0 |
% |
|
|
0 |
% |
|
|
0 |
% |
Expected volatility |
|
|
92 |
% |
|
|
92 |
% |
|
|
92 |
% |
Risk-free interest rate |
|
|
1.72 |
% |
|
|
0.89 |
% |
|
|
0.82 |
% |
Expected term |
|
5.6 years |
|
|
5.6 years |
|
|
5.6 years |
|
|
| Stock-based compensation expense |
The following table shows total stock-based compensation expense included in the accompanying consolidated statements of comprehensive loss for the years ended December 31, 2014, 2013, and 2012 (in thousands):
| |
|
Year Ended December 31, |
|
| |
|
2014 |
|
|
2013 |
|
|
2012 |
|
Research and development |
|
$ |
5,557 |
|
|
$ |
2,358 |
|
|
$ |
2,391 |
|
Selling, general and administrative |
|
|
5,215 |
|
|
|
2,741 |
|
|
|
1,893 |
|
Total stock-based compensation expense |
|
$ |
10,772 |
|
|
$ |
5,099 |
|
|
$ |
4,284 |
|
|