Credit Facilities (Details) (USD $)	6 Months Ended
	Jun. 30, 2012
Silicon Valley Bank
Line of Credit Facility [Line Items]
Borrowing capacity	$ 30,000,000
Minimum required net worth	50,000,000
Potential increase in borrowing capacity	20,000,000
Borrowing base	40,000,000
Borrowing base, period	90 days
Cash and cash equivalents, net of amount outstanding under credit facility	20,000,000
Amount outstanding	0
Cash management services | Silicon Valley Bank
Line of Credit Facility [Line Items]
Borrowing capacity	300,000
Letter of credit | Silicon Valley Bank
Line of Credit Facility [Line Items]
Amount outstanding	$ 0
Prime rate | Silicon Valley Bank
Line of Credit Facility [Line Items]
Interest rate over prime	1.00%
Threshold one
Line of Credit Facility [Line Items]
Customer accounts receivable concentration limit	25.00%
Threshold two
Line of Credit Facility [Line Items]
Customer accounts receivable concentration limit	50.00%
Threshold three
Line of Credit Facility [Line Items]
Customer accounts receivable concentration limit	85.00%