Investments Summary of Investments (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013	Dec. 31, 2013
Investments [Abstract]
“Available-for-sale” marketable equity securities, cost basis	$ 12,937,000			$ 12,937,000			$ 2,879,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	19,338,000	[1]		19,338,000	[1]		2,177,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	(1,297,000)			(1,297,000)			(587,000)
“Available-for-sale” marketable equity securities, at fair value	30,978,000			30,978,000			4,469,000
Investments accounted for under cost method	143,824,000			143,824,000			135,819,000
Marketable Securities	174,802,000			174,802,000			140,288,000
Unrealized holding (losses) gains arising during the period	(2,734,000)		44,000	16,045,000		360,000
Unrealized Loss in Investment in Privately Held Entities	$ 0			$ 0			$ 0

[1] The increase in our investments during the six months ended June 30, 2014, was primarily related to an increase in unrealized gains of approximately $16.0 million related to our investments in publicly traded life science companies. These unrealized gains are a component of our comprehensive income, within our stockholders’ equity, and have not been recognized in the accompanying consolidated statement of income for the six months ended June 30, 2014.