Fair Value Measurements - Summary Of Investments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 12,904	$ 4,301
Gross unrealized gains in Accumulated OCI	876	3,739
Gross unrealized losses in Accumulated OCI	(4,551)	0
Gain/(Loss) in Accumulated Deficit	4,062	4,022
Fair value	13,291	12,062
Common stock investments, available for sale
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,479	3,376
Gross unrealized gains in Accumulated OCI	660	2,698
Gross unrealized losses in Accumulated OCI	(4,551)	0
Gain/(Loss) in Accumulated Deficit
Fair value	7,588	6,074
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,425
Gross unrealized gains in Accumulated OCI	216
Gross unrealized losses in Accumulated OCI
Gain/(Loss) in Accumulated Deficit	4,062
Fair value	5,703
Common stock options/warrants
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