CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
General and administrative expense	$ 5,589	$ 4,947
Operating loss	(5,589)	(4,947)
Other income (loss)	(1,435)	249
Interest income	798	801
Interest expense	(2,690)	(1,198)
Equity income (loss)	2,746	(17,002)
Net loss before income taxes	(6,170)	(22,097)
Income tax benefit (expense)	0	0
Net loss	$ (6,170)	$ (22,097)
Net loss per share:
Basic (in dollars per share)	$ (0.30)	$ (1.08)
Diluted (in dollars per share)	$ (0.30)	$ (1.08)
Weighted average shares used in computing loss per share:
Basic (in shares)	20,506	20,380
Diluted (in shares)	20,506	20,380