Stock-Based Compensation (Details 1) (Details) (USD $) | 6 Months Ended |
In Thousands, except Share data, unless otherwise specified | Jun. 30, 2014 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | ' |
Options Outstanding, Shares, Beginning of Period | 12,236,400 |
Options Outstanding, Shares, Options exercised | -2,476,757 |
Options Outstanding, Shares, Options canceled | -36 |
Options Outstanding, Shares, forfeited | -127,729 |
Options Outstanding, Shares, End of Period | 9,631,878 |
Options Outstanding, Shares, Vested and Expected to Vest | 9,395,479 |
Options Outstanding, Shares, Exercisable | 4,761,733 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward] | ' |
Options Outstanding, Weighted Average Exercise Price, Beginning of Period, USD per share | $7.64 |
Options Outstanding, Weighted Average Exercise Price, Options exercised, USD per share | $3.79 |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price | $8.23 |
Options Outstanding, Weighted Average Exercise Price, Options forfeited, USD per share | $12.74 |
Options Outstanding, Weighted Average Exercise Price, End of Period, USD per share | $8.56 |
Options Outstanding, Weighted Average Exercise Price Per Share, Vested and Expected to Vest, USD per share | $8.46 |
Options Outstanding, Weighted Average Exercise Price Per Share, Exercisable, USD per share | $5.91 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | '7 years 4 months 17 days |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term | '7 years 4 months 9 days |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term | '6 years 6 months 14 days |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] | ' |
Options Outstanding, Aggregate Intrinsic Value | $604,546 |
Options Outstanding, Aggregate Intrinsic Value, Vested and Expected to Vest | 590,683 |
Options Outstanding, Aggregate Intrinsic Value, Exercisable | $311,508 |