|
Cash, Cash Equivalents and Investments (Available For Sale Securities) (Details) (USD $)
In Thousands, unless otherwise specified |
Sep. 30, 2014
|
Dec. 31, 2013
|
|---|---|---|
| Schedule of Available-for-sale Securities [Line Items] | ||
| Adjusted Cost | $ 386,607 | $ 361,183 |
| Unrealized Gains | 26 | 6 |
| Unrealized Losses | (299) | (262) |
| Fair Value | 386,334 | 360,927 |
|
Money Market Funds
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Adjusted Cost | 91,780 | 98,437 |
| Fair Value | 91,780 | 98,437 |
|
Commercial Paper
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Adjusted Cost | 60,743 | 101,773 |
| Fair Value | 60,743 | 101,773 |
|
Corporate Debt Securities
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Adjusted Cost | 220,969 | 155,273 |
| Unrealized Gains | 24 | 6 |
| Unrealized Losses | (286) | (258) |
| Fair Value | 220,707 | 155,021 |
|
US Government Agencies Debt Securities
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Adjusted Cost | 13,115 | 5,700 |
| Unrealized Gains | 2 | |
| Unrealized Losses | (13) | (4) |
| Fair Value | $ 13,104 | $ 5,696 |