Fair Value Measurements - Summary Of Investments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 4,745	$ 4,301
Gross unrealized gains in Accumulated OCI	3,645	3,739
Gross unrealized losses in Accumulated OCI	(150)	0
Gain/(Loss) in Accumulated Deficit	3,762	4,022
Fair value	12,002	12,062
Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,320	3,376
Gross unrealized gains in Accumulated OCI	2,035	2,698
Gross unrealized losses in Accumulated OCI	(150)	0
Gain/(Loss) in Accumulated Deficit
Fair value	5,205	6,074
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,425
Gross unrealized gains in Accumulated OCI	1,610
Gross unrealized losses in Accumulated OCI
Gain/(Loss) in Accumulated Deficit	3,762
Fair value	6,797
Common stock options/warrants [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		925
Gross unrealized gains in Accumulated OCI		1,041
Gross unrealized losses in Accumulated OCI		0
Gain/(Loss) in Accumulated Deficit		4,022
Fair value		$ 5,988