Certain Financial Statement Information - Short-Term Investments Schedule of Maturities (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Schedule of cost and estimated fair values of available-for-sale securities with stated maturities by contractual maturity
Less than 1 year, Cost	$ 15,500
Mature in 1 - 2 years, Cost	31,021
Mature in 3 - 5 years, Cost	11,310
Mature after 5 years, Cost	0
Cost, Total	57,831
Less than 1 year, Fair Value	15,485
Mature in 1 - 2 years, Fair Value	30,908
Mature in 3 - 5 years, Fair Value	11,280
Mature after 5 years, Fair Value	0
Fair Value, Total	$ 57,673