|
Fair Value Measurements (Recurring Fair Value Measurements) (Details) (USD $)
In Thousands, unless otherwise specified
|
Dec. 31, 2014
|
Dec. 31, 2013
|
| Cash Equivalents [Abstract] |
|
|
| Total cash equivalents |
$ 50,359 |
$ 41,260 |
| Marketable Securities [Abstract] |
|
|
| Total marketable securities |
30,588 |
9,668 |
| Total |
80,947 |
50,928 |
| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |
|
|
| Cash Equivalents [Abstract] |
|
|
| Total cash equivalents |
50,359 |
41,260 |
| Marketable Securities [Abstract] |
|
|
| Total marketable securities |
30,540 |
5,507 |
| Total |
80,899 |
46,767 |
| Significant Other Observable Inputs (Level 2) [Member] |
|
|
| Cash Equivalents [Abstract] |
|
|
| Total cash equivalents |
0 |
0 |
| Marketable Securities [Abstract] |
|
|
| Total marketable securities |
48 |
4,161 |
| Total |
48 |
4,161 |
| Marketable Securities [Member] |
|
|
| Marketable Securities [Abstract] |
|
|
| U.S. treasury securities |
30,020 |
4,999 |
| Certificates of Deposit, Fair Value Disclosure |
48 |
4,161 |
| Mutual funds |
520 |
508 |
| Marketable Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |
|
|
| Marketable Securities [Abstract] |
|
|
| U.S. treasury securities |
30,020 |
4,999 |
| Certificates of Deposit, Fair Value Disclosure |
0 |
0 |
| Mutual funds |
520 |
508 |
| Marketable Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |
|
|
| Marketable Securities [Abstract] |
|
|
| U.S. treasury securities |
0 |
0 |
| Certificates of Deposit, Fair Value Disclosure |
48 |
4,161 |
| Mutual funds |
0 |
0 |
| Cash Equivalents [Member] |
|
|
| Cash Equivalents [Abstract] |
|
|
| Money market funds |
50,359 |
41,260 |
| Cash Equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |
|
|
| Cash Equivalents [Abstract] |
|
|
| Money market funds |
50,359 |
41,260 |
| Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] |
|
|
| Cash Equivalents [Abstract] |
|
|
| Money market funds |
$ 0 |
$ 0 |