Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2016

Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]

Summary of financial instruments measured at fair value on a recurring basis

The following tables present the financial instruments that were measured at fair value on a recurring basis at March 31, 2016 and December 31, 2015, by level within the fair value hierarchy (in thousands):

	March 31, 2016
	Level 1		Level 2		Level 3		Total
Money market funds	$	11,130	$	—	$	—	$	11,130
Common shares of CO2 Solutions	—		1,459		—		1,459
Total	$	11,130	$	1,459	$	—	$	12,589

	December 31, 2015
	Level 1		Level 2		Level 3		Total
Money market funds	$	11,120	$	—	$	—	$	11,120
Common shares of CO2 Solutions	—		1,549		—		1,549
Total	$	11,120	$	1,549	$	—	$	12,669