Cash, Cash Equivalents and Investments (Details Textual) (USD $)	6 Months Ended
	Jun. 30, 2012
Cash Cash equivalents and Investments (Textual) [Abstract]
Gross unrealized loss available for sale equity securities	4,319
Maximum [Member]
Cash Cash equivalents and Investments (Textual) [Abstract]
Maturities Period of Short-term investments and securities	1 year
Maximum [Member] | Commercial Paper [Member]
Cash Cash equivalents and Investments (Textual) [Abstract]
Period of held to maturity securities continuous unrealized loss position	12 months
Minimum [Member]
Cash Cash equivalents and Investments (Textual) [Abstract]
Maturities Period of Short-term investments and securities	90 days