|
Fair Value (Details) (USD $)
In Thousands, unless otherwise specified |
Dec. 31, 2013
|
Jan. 31, 2013
|
|---|---|---|
| Assets: | ||
| Total assets measured at fair value | $ 360,927 | $ 66,269 |
|
Money market funds
|
||
| Assets: | ||
| Total assets measured at fair value | 98,437 | 32,522 |
|
Commercial paper
|
||
| Assets: | ||
| Total assets measured at fair value | 101,773 | 24,092 |
|
Corporate debt securities
|
||
| Assets: | ||
| Total assets measured at fair value | 155,021 | 9,655 |
|
U.S. government and government agency debt securities
|
||
| Assets: | ||
| Total assets measured at fair value | 5,696 | |
|
Quoted Prices in Active Markets for Identical Instruments (Level 1)
|
||
| Assets: | ||
| Total assets measured at fair value | 98,437 | 32,522 |
|
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Money market funds
|
||
| Assets: | ||
| Total assets measured at fair value | 98,437 | 32,522 |
|
Significant Other Observable Inputs (Level 2)
|
||
| Assets: | ||
| Total assets measured at fair value | 262,490 | 33,747 |
|
Significant Other Observable Inputs (Level 2) | Commercial paper
|
||
| Assets: | ||
| Total assets measured at fair value | 101,773 | 24,092 |
|
Significant Other Observable Inputs (Level 2) | Corporate debt securities
|
||
| Assets: | ||
| Total assets measured at fair value | 155,021 | 9,655 |
|
Significant Other Observable Inputs (Level 2) | U.S. government and government agency debt securities
|
||
| Assets: | ||
| Total assets measured at fair value | 5,696 | |
|
Total
|
||
| Assets: | ||
| Total assets measured at fair value | 360,927 | 66,269 |
|
Total | Money market funds
|
||
| Assets: | ||
| Total assets measured at fair value | 98,437 | 32,522 |
|
Total | Commercial paper
|
||
| Assets: | ||
| Total assets measured at fair value | 101,773 | 24,092 |
|
Total | Corporate debt securities
|
||
| Assets: | ||
| Total assets measured at fair value | 155,021 | 9,655 |
|
Total | U.S. government and government agency debt securities
|
||
| Assets: | ||
| Total assets measured at fair value | 5,696 | |
|
Level 3
|
||
| Assets: | ||
| Total assets measured at fair value | $ 0 | $ 0 |