Summary of Significant Accounting Policies Schedule of Other Income (Loss), Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accounting Policies [Abstract]
(Loss) gain on warrants	$ (168)	$ 65
Interest income	1,000	650
Accretion of interest income from debt discount on notes receivable	66	35
Out-of-period adjustment	1,231	0
Other (expense) income	(3)	59
Other income, net	$ 2,126	$ 809