Investments (Tables)
12 Months Ended
Dec. 31, 2014
Fair Value Disclosures [Abstract]  
Fair Value Information of Short and Long-term Investments
The following table summarizes the fair value information of short and long-term investments as of December 31, 2014 and 2013, respectively (in thousands):
 
December 31, 2014
 
Level 1
 
Level 2
 
Level 3
 
Total
Mutual funds
$
1,071

 
$

 
$

 
$
1,071

Corporate notes and bonds

 
62,550

 

 
62,550

U.S. government and agency securities

 
34,987

 

 
34,987

Certificates of deposit

 
25,000

 

 
25,000

Total
$
1,071

 
$
122,537

 
$

 
$
123,608

 
December 31, 2013
 
Level 1
 
Level 2
 
Level 3
 
Total
Demand notes
$

 
$
719

 
$

 
$
719

Corporate notes and bonds

 
16,244

 

 
16,244

Certificates of deposit

 
90,000

 

 
90,000

Total
$

 
$
106,963

 
$

 
$
106,963

Schedule of Difference Between Amortized Cost and Fair Value
The following table summarizes the differences between amortized cost and fair value of short and long-term investments as of December 31, 2014 and 2013, respectively (in thousands):
 
December 31, 2014
 
 
 
 
 
Gross unrealized
 
 
 
Maturities
 
Amortized Cost
 
Gain
 
Loss
 
Fair Value
Short-term
 
 
 
 
 
 
 
 
 
Corporate notes and bonds
1 year or less
 
10,947

 
33

 

 
10,980

Long-term
 
 
 
 
 
 
 
 
 
Corporate notes and bonds
3 years or less
 
51,874

 

 
(304
)
 
51,570

U.S. government and agency securities
3 years or less
 
35,000

 

 
(13
)
 
34,987

Certificates of deposit
3 years or less
 
25,000

 

 

 
25,000

Total
 
 
$
122,821

 
$
33

 
$
(317
)
 
$
122,537

The above table does not include $1.1 million for mutual funds at December 31, 2014, which are recorded as trading securities and are therefore not recorded at amortized cost.

 
December 31, 2013
 
 
 
 
 
Gross unrealized
 
 
 
Maturities
 
Amortized Cost
 
Gain
 
Loss
 
Fair Value
Short-term
 
 
 
 
 
 
 
 
 
Demand notes
1 year or less
 
$
719

 
$

 
$

 
$
719

Corporate notes and bonds
1 year or less
 
5,132

 
50

 

 
5,182

Certificate of deposit
1 year or less
 
60,000

 

 

 
60,000

Long-term
 
 
 
 
 
 
 
 
 
Corporate notes and bonds
3 years or less
 
11,037

 
25

 

 
11,062

Certificate of deposit
3 years or less
 
30,000

 

 

 
30,000

Total
 
 
$
106,888

 
$
75

 
$

 
$
106,963