Acquisition (Details) (USD $)	12 Months Ended				12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010 Avalon [Member]	Dec. 31, 2010 Avalon [Member] Completed technology [Member]	Dec. 31, 2012 Avalon [Member] Completed technology [Member] Minimum [Member]	Dec. 31, 2012 Avalon [Member] Completed technology [Member] Maximum [Member]	Dec. 31, 2010 Avalon [Member] Customer relationships [Member]	Dec. 31, 2012 Avalon [Member] Customer relationships [Member] Minimum [Member]	Dec. 31, 2012 Avalon [Member] Customer relationships [Member] Maximum [Member]	Dec. 31, 2012 Avalon [Member] Backlog [Member]	Dec. 31, 2010 Avalon [Member] Backlog [Member]
Business Acquisition [Line Items]
Avalon purchase cash consideration			$ 8,000,000
Required future installments resulting from contingent consideration arrangement			7,500,000
Compensation expense, acquisition related	1,900,000	1,900,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]
Current assets, net of cash acquired			1,902,000
Fixed and other long-term assets, net			729,000
Intangible assets				5,670,000			910,000				730,000
Goodwill			2,329,000
Total assets acquired			12,270,000
Deferred tax liabilities			(3,550,000)
Other liabilities assumed			(716,000)
Net assets acquired			$ 8,004,000
Amortization life (in years)					6 years	10 years		5 years	6 years	1 year