Annual report pursuant to Section 13 and 15(d)

Marketable Securities (Components of Cash Equivalents and Marketable Securitieis) (Details)

v3.3.1.900
Marketable Securities (Components of Cash Equivalents and Marketable Securitieis) (Details)
$ in Thousands
Dec. 31, 2015
USD ($)
security
Dec. 31, 2014
USD ($)
security
Cash Equivalents and Marketable Securities [Line Items]    
Adjusted Cost $ 11,683 $ 15,165
Gross Unrealized Gains 986 125
Gross Unrealized Losses 0 0
Estimated Fair Value $ 12,669 $ 15,290
Number of marketable securities in unrealized loss position | security 0 0
Money market funds [Member]    
Cash Equivalents and Marketable Securities [Line Items]    
Adjusted Cost $ 11,120 $ 14,602
Gross Unrealized Gains 0 0
Gross Unrealized Losses 0 0
Estimated Fair Value 11,120 14,602
Common shares of CO2 Solutions [Member]    
Cash Equivalents and Marketable Securities [Line Items]    
Adjusted Cost 563 563
Gross Unrealized Gains 986 125
Gross Unrealized Losses 0 0
Estimated Fair Value $ 1,549 $ 688