Balance Sheet Components (Available-for-Sale Investments in Unrealized Loss Position) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	$ 7,845	$ 15,497
Unrealized Loss, Less than 12 months	(1)	(3)
Corporate Bonds/Notes [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	7,845	5,369
Unrealized Loss, Less than 12 months	$ (1)	(1)
U.S. Government Securitie [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months		10,128
Unrealized Loss, Less than 12 months		$ (2)