|
|
|
|
Three Months Ended |
|
Six Months Ended |
|
|
|
|
June 30, |
|
June 30, |
|
|
|
|
2012 |
|
2011 |
|
2012 |
|
2011 |
|
|
Number of options granted |
|
195,000 |
|
22,000 |
|
235,000 |
|
34,000 |
|
|
Grant date fair value of options granted per share |
|
$ |
5.17 |
|
$ |
17.76 |
|
$ |
5.68 |
|
$ |
17.53 |
|
|
Weighted average exercise price of options granted |
|
$ |
9.19 |
|
$ |
31.16 |
|
$ |
10.06 |
|
$ |
30.61 |
|
|
Volatility (1) |
|
59 |
% |
59 |
% |
60 |
% |
59 |
% |
|
Risk free interest rate (2) |
|
1.4 |
% |
2.4 |
% |
1.4 |
% |
2.5 |
% |
|
Expected term (in years) (3) |
|
6.3 |
|
6.3 |
|
6.3 |
|
6.3 |
|
|
Expected annual dividends |
|
None |
|
None |
|
None |
|
None |
|
(1) Expected volatility is based on the historical volatility of our common stock over a preceding period commensurate with the expected term of the award.
(2) The risk free rate for periods within the expected term of the stock option is based on the U.S. Treasury yield curve in effect at the time of grant.
(3) The expected term was calculated as the average between the vesting term and the contractual term, weighted by tranche. We used this simplified method as we do not have sufficient historical data in order to calculate a more appropriate estimate. |