The Company and Summary of Significant Accounting Policies Non-marketable securities (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Security Owned Not Readily Marketable [Line Items]
Payments to Acquire Investments			$ 625
privately-held companies [Member] | Preferred Stock
Security Owned Not Readily Marketable [Line Items]
Payments to Acquire Investments		$ 600		$ 2,500
privately-held companies [Member] | Convertible Debt Securities [Member]
Security Owned Not Readily Marketable [Line Items]
Payments to Acquire Investments	$ 600