Significant Customer Concentration (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Customer A [Member]
Revenue, Major Customer [Line Items]
Percentage of revenue generated by single major customer (in hundredths)	11.00%	22.00%	8.00%	23.00%
Customer B [Member]
Revenue, Major Customer [Line Items]
Percentage of revenue generated by single major customer (in hundredths)	9.00%	11.00%	7.00%	11.00%

Percentage of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues.

No definition available.

Name:	us-gaap_EntityWideRevenueMajorCustomerPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration