Fair Value Measurements (Schedule of Financial Instruments Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	$ 12,256	$ 12,669
Investment owned (shares)	10,000,000
Level 1 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	$ 11,141	11,120
Level 2 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	1,115	1,549
Level 3 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	0	0
Money market funds [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	11,141	11,120
Money market funds [Member] | Level 1 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	11,141	11,120
Money market funds [Member] | Level 2 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	0	0
Money market funds [Member] | Level 3 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	0	0
Common shares of CO2 Solution [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	1,115	1,549
Common shares of CO2 Solution [Member] | Level 1 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	0	0
Common shares of CO2 Solution [Member] | Level 2 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	1,115	1,549
Common shares of CO2 Solution [Member] | Level 3 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Total financial assets measured at fair value on a recurring basis	$ 0	$ 0