Investments in Non-Publicly Traded Companies (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Additional Investments	$ 0	$ 0.1
Neurone II [Member]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	3.00%
Munich Venture Partners Fund [Member]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	0.42%