Commitments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	1 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	May 31, 2007 Lease Agreements [Member]	Sep. 30, 2008 Expansion Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Rent escalation, percentage				4.00%	6.00%
Allowance toward cost of leasehold improvements				$ 0.2	$ 0.5
Rent expense	$ 2.9	$ 2.1	$ 1.6

Rental expense incurred for leased assets including furniture and equipment which has not been recognized in costs and expenses applicable to sales and revenues; for example, cost of goods sold or other operating costs and expenses.

No definition available.

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration