Commitments and Contingencies (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Commitments and contingencies (Textual) [Abstract]
Operating leases expenses	$ 348,000	$ 259,000	$ 636,000	$ 514,000
Credit amount as collateral	700,000		700,000		700,000
Maximum deductible amount for defending lawsuit			300,000
Receivable reimbursable expenses	$ 1,012		$ 1,012