Significant Accounting Policies (Details 6) (USD $)
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6 Months Ended | |
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Jun. 30, 2013
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Jun. 30, 2012
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Employee Stock Options:
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Weighted-average assumptions | ||
Risk-free interest rate (as a percent) | 1.00% | 0.80% |
Dividend yield (as a percent) | 0.00% | 0.00% |
Volatility (as a percent) | 51.50% | 51.10% |
Expected life | 5 years 1 month 6 days | 5 years 1 month 6 days |
ESPP:
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Weighted-average assumptions | ||
Risk-free interest rate (as a percent) | 0.10% | 0.10% |
Dividend yield (as a percent) | 0.00% | 0.00% |
Volatility (as a percent) | 61.40% | 42.30% |
Expected life | 6 months | 6 months |
RSUs
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Weighted-average assumptions | ||
Vesting period | 4 years | |
RSUs | Employees
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Weighted-average assumptions | ||
Weighted-average grant date fair value (in dollars per share) | $ 14.48 | $ 7.60 |
Board of Director Stock Options:
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Weighted-average assumptions | ||
Risk-free interest rate (as a percent) | 2.30% | |
Dividend yield (as a percent) | 0.00% | |
Volatility (as a percent) | 52.40% | |
Expected life | 7 years 3 months 18 days |