Organization and Summary of Significant Accounting Policies (Marketable Securities Sold) (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Investments in Privately Held Companies
Proceeds from sales of marketable securities		$ 10,155,000	$ 5,117,000
Realized gains on available-for-sale marketable securities	$ 676,000	2,807,000	2,009,000
Amount reclassified out of accumulated other comprehensive income	345,000	1,127,000	787,000
Invitae
Investments in Privately Held Companies
Carrying value	$ 10,700,000		10,700,000
Amount reclassified out of accumulated other comprehensive income		1,100,000	787,000
Amount reclassified out of accumulated other comprehensive income, tax portion		821,000	448,000
Common Stock | Sale | Invitae
Investments in Privately Held Companies
Proceeds from sales of marketable securities		$ 10,200,000	$ 5,100,000
Cost per share (in dollars per share)		$ 6.28	$ 6.28
Realized gains on available-for-sale marketable securities		$ 2,800,000	$ 2,000,000