Cash, Cash Equivalents and Investments (Details Textual)	3 Months Ended
	Mar. 31, 2013
Cash, Cash equivalents and Investments (Additional Textual) [Abstract]
Initial maturities period of cash and cash equivalents	3 months
Maximum [Member]
Cash, Cash equivalents and Investments (Textual) [Abstract]
Maturities period of Short-term investments and securities	1 year