Credit Facilities (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Credit Facility [Line Items]
Letters of credit outstanding	$ 2,800,000	$ 2,800,000
Line of Credit Facility, Covenant Compliance	. We are currently in compliance with all covenant requirements.
Line of Credit Facility, Interest Rate Description	prime rate
Line of Credit Facility, Collateral	and are secured by substantially all of our accounts receivable, deposit and securities accounts. The agreement provides for a negative pledge on our inventory and intellectual property, subject to certain exceptions
Silicon Valley Bank
Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	17,700,000
Credit facility | Silicon Valley Bank
Credit Facility [Line Items]
Borrowing capacity	30,000,000
Minimum net worth requirement	50,000,000
Line of Credit Facility, Covenant Terms, Borrowing Base, Possible Increase	20,000,000
Period for borrowing base requirement	90 days
Cash and cash equivalents, net of amount outstanding under credit agreement	20,000,000
Variable rate basis	prime
Interest rate over prime	1.00%
Letters of credit | Silicon Valley Bank
Credit Facility [Line Items]
Letters of credit outstanding	2,800,000
Threshold One [Member]
Credit Facility [Line Items]
Customer accounts receivable concentration limit	25.00%
Threshold Two [Member]
Credit Facility [Line Items]
Customer accounts receivable concentration limit	50.00%
Threshold Three [Member]
Credit Facility [Line Items]
Customer accounts receivable concentration limit	70.00%
Required Borrowing Base Immediately Preceeding 90 Days [Member] | Credit facility | Silicon Valley Bank
Credit Facility [Line Items]
Borrowing base requirement	$ 40,000,000