|
Fair Value Measurements (Details) (USD $)
In Thousands, unless otherwise specified
|
3 Months Ended |
|
|
Mar. 31, 2015
|
Dec. 31, 2014
|
| Minimum |
|
|
| Fair Value Measurements |
|
|
| Maturity period of long-term investments |
1 year |
|
| Maximum |
|
|
| Fair Value Measurements |
|
|
| Maturity period of long-term investments |
2 years |
|
| Measured on a recurring basis |
|
|
| Fair Value Measurements |
|
|
| Assets, Adjusted Cost |
84,124 |
$ 97,266 |
| Assets, Unrealized Gains |
18 |
2 |
| Assets, Unrealized Losses |
(28) |
(49) |
| Assets, Fair Value |
84,114 |
97,219 |
| Measured on a recurring basis | Cash and Cash Equivalents |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
14,637 |
29,187 |
| Measured on a recurring basis | Short-term investments |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
50,707 |
53,523 |
| Measured on a recurring basis | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
18,770 |
14,509 |
| Measured on a recurring basis | Cash |
|
|
| Fair Value Measurements |
|
|
| Assets, Adjusted Cost |
4,875 |
13,077 |
| Assets, Fair Value |
4,875 |
13,077 |
| Measured on a recurring basis | Cash | Cash and Cash Equivalents |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
4,875 |
13,077 |
| Measured on a recurring basis | Level 1 |
|
|
| Fair Value Measurements |
|
|
| Assets, Adjusted Cost |
10,762 |
16,110 |
| Assets, Fair Value |
10,762 |
16,110 |
| Measured on a recurring basis | Level 1 | Cash and Cash Equivalents |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
9,762 |
16,110 |
| Measured on a recurring basis | Level 1 | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
1,000 |
|
| Measured on a recurring basis | Level 1 | Money market funds |
|
|
| Fair Value Measurements |
|
|
| Assets, Adjusted Cost |
9,762 |
16,110 |
| Assets, Fair Value |
9,762 |
16,110 |
| Measured on a recurring basis | Level 1 | Money market funds | Cash and Cash Equivalents |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
9,762 |
16,110 |
| Measured on a recurring basis | Level 1 | U.S. government notes |
|
|
| Fair Value Measurements |
|
|
| Assets, Adjusted Cost |
1,000 |
|
| Assets, Fair Value |
1,000 |
|
| Measured on a recurring basis | Level 1 | U.S. government notes | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Assets, Fair Value |
1,000 |
|
| Measured on a recurring basis | Level 2 |
|
|
| Fair Value Measurements |
|
|
| Adjusted cost, Available-for-sale investments |
68,487 |
68,079 |
| Unrealized Gains, available-for-sale investments |
18 |
2 |
| Unrealized Losses, available-for-sale investments |
(28) |
(49) |
| Fair value, Available-for-sale investments |
68,477 |
68,032 |
| Measured on a recurring basis | Level 2 | Short-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
50,707 |
53,523 |
| Measured on a recurring basis | Level 2 | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
17,770 |
14,509 |
| Measured on a recurring basis | Level 2 | Asset-backed securities |
|
|
| Fair Value Measurements |
|
|
| Adjusted cost, Available-for-sale investments |
7,056 |
4,458 |
| Unrealized Gains, available-for-sale investments |
1 |
|
| Unrealized Losses, available-for-sale investments |
(2) |
(3) |
| Fair value, Available-for-sale investments |
7,055 |
4,455 |
| Measured on a recurring basis | Level 2 | Asset-backed securities | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
7,055 |
4,455 |
| Measured on a recurring basis | Level 2 | Corporate bonds |
|
|
| Fair Value Measurements |
|
|
| Adjusted cost, Available-for-sale investments |
52,525 |
54,321 |
| Unrealized Gains, available-for-sale investments |
14 |
2 |
| Unrealized Losses, available-for-sale investments |
(26) |
(46) |
| Fair value, Available-for-sale investments |
52,513 |
54,277 |
| Measured on a recurring basis | Level 2 | Corporate bonds | Short-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
43,307 |
46,726 |
| Measured on a recurring basis | Level 2 | Corporate bonds | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
9,206 |
7,551 |
| Measured on a recurring basis | Level 2 | Commercial paper |
|
|
| Fair Value Measurements |
|
|
| Adjusted cost, Available-for-sale investments |
4,397 |
6,797 |
| Fair value, Available-for-sale investments |
4,397 |
6,797 |
| Measured on a recurring basis | Level 2 | Commercial paper | Short-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
4,397 |
6,797 |
| Measured on a recurring basis | Level 2 | U.S. agency securities |
|
|
| Fair Value Measurements |
|
|
| Adjusted cost, Available-for-sale investments |
4,509 |
2,503 |
| Unrealized Gains, available-for-sale investments |
3 |
|
| Fair value, Available-for-sale investments |
4,512 |
2,503 |
| Measured on a recurring basis | Level 2 | U.S. agency securities | Short-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
3,003 |
|
| Measured on a recurring basis | Level 2 | U.S. agency securities | Long-term investments |
|
|
| Fair Value Measurements |
|
|
| Fair value, Available-for-sale investments |
1,509 |
$ 2,503 |