Basis of Presentation and Summary of Significant Accounting Policies (Textual) (Details) (USD $)	3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended		12 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2013 reporting_unit operating_segment Criteria	Dec. 31, 2012	Sep. 30, 2013 Total revenues [Member] Customer concentration risk [Member] customer	Sep. 30, 2013 Total revenues [Member] Customer concentration risk [Member] customer	Sep. 30, 2013 Accounts Receivable [Member] Customer concentration risk [Member] customer	Dec. 31, 2012 Accounts Receivable [Member] Customer concentration risk [Member] customer	Sep. 30, 2013 Equity Securities [Member]	Sep. 30, 2013 Debt Securities [Member]	Sep. 30, 2013 Customer A [Member] Total revenues [Member] Customer concentration risk [Member]	Sep. 30, 2013 Customer A [Member] Total revenues [Member] Customer concentration risk [Member]	Sep. 30, 2013 Customer B [Member] Total revenues [Member] Customer concentration risk [Member]	Sep. 30, 2013 Customer B [Member] Total revenues [Member] Customer concentration risk [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of major customers (customer)				5	5	5	5
Major customers, concentration risk percentage (percent)				59.00%	81.00%	89.00%	84.00%			34.00%	47.00%	21.00%	10.00%
Maturity date of highly liquid investments (months)		3 months
Maturity period of marketable securities included in non-current asset (years)		1 year
OTTI recorded in selling, general and administrative expenses	$ 800,000
Gross unrealized losses		$ 0	$ 0					$ 0	$ 0
Number of operating segments (operating segment)		1
Number of reportable units (reportable unit)		1
Number revenue recognition criteria (criteria)		4