Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 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 June 30, 2016 and December 31, 2015 by level within the fair value hierarchy (in thousands):

	June 30, 2016
	Level 1		Level 2		Level 3		Total
Money market funds	$	11,141	$	—	$	—	$	11,141
Common shares of CO2 Solutions	—		1,115		—		1,115
Total	$	11,141	$	1,115	$	—	$	12,256

	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