Commitments and Contingencies (Future Minimum Rental Commitments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Operating Leased Assets [Line Items]
2013	$ 2,136
2014	3,596
2015	4,171
2016	4,271
2017	2,442
Thereafter	14,517
Total minimum lease payments	31,133
Operating Leases [Member]
Operating Leased Assets [Line Items]
2013	2,431
2014	3,797
2015	4,171
2016	4,271
2017	2,442
Thereafter	14,517
Total minimum lease payments	31,629
Sublease Member
Operating Leased Assets [Line Items]
2013	(295)
2014	(201)
2015
2016
2017
Thereafter
Total minimum lease payments	$ (496)