Balance Sheet Components - Investments, Contractual Maturities (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amortized Cost, Due in one year or less	$ 12,882
Amortized Cost, Due in one year to five years	3,496
Amortized Cost	16,378
Fair Value, Due in one year or less	12,867
Fair Value, Due in one year to five years	3,490
Fair Value	$ 16,357