Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Allowance for accounts receivable	$ 68	$ 47
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	28,471,775	24,464,163
Common stock, shares outstanding (in shares)	28,471,775	24,464,163
5.50% Series B cumulative convertible preferred stock, $0.01 par value, 2,600,000 shares issued and outstanding at December 31, 2015
Convertible preferred stock (in dollars per share)	$ 0.01	$ 0.01
Convertible preferred stock, shares issued (in shares)	2,600,000	2,600,000
Convertible preferred stock, shares outstanding (in shares)	2,600,000	2,600,000
Preferred stock dividend rate	5.50%	5.50%