Organization and Summary of Significant Accounting Policies (Marketable Securities Sold) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Investments in Privately Held Companies
Proceeds from sales of marketable securities	$ 10,155,000	$ 3,579,000
Realized gains on available-for-sale marketable securities	2,807,000	1,333,000
Amount reclassified out of accumulated other comprehensive income	1,126,000	442,000
Invitae
Investments in Privately Held Companies
Fair value		18,900,000
Carrying value		11,600,000
Amount reclassified out of accumulated other comprehensive income	1,100,000	442,000
Amount reclassified out of accumulated other comprehensive income, tax portion	821,000	251,000
Common Stock | Sale | Invitae
Investments in Privately Held Companies
Proceeds from sales of marketable securities	$ 10,200,000	$ 3,600,000
Cost per share (in dollars per share)	$ 6.28	$ 6.28
Realized gains on available-for-sale marketable securities	$ 2,800,000	$ 1,300,000