Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Deficit	Series A Preferred Stock	Series A Preferred Stock Preferred Stock	Series A Preferred Stock Common Stock	Series A Preferred Stock Additional Paid-In Capital	Series B Preferred Stock	Series B Preferred Stock Preferred Stock	Series B Preferred Stock Common Stock	Series B Preferred Stock Additional Paid-In Capital
Beginning Balance at Dec. 31, 2018	$ 29,742	$ 71	$ 381,004	$ (47)	$ (351,288)		$ 2				$ 0
Beginning Balance (in shares) at Dec. 31, 2018		70,793,725					2,093,155				3,100
Stock-based compensation	1,141		1,141
Stock option exercises	472		472
Stock option exercises (in shares)		150,275
Restricted stock awards	0	$ (1)	1
Restricted stock awards (in shares)		500,366
Series B conversion to common stock										$ 0		$ 4	$ (4)
Series B conversion to common stock (in shares)											700	3,888,888
Net income (loss)	(3,833)				(3,833)
Ending Balance at Mar. 31, 2019	27,522	$ 74	382,614	(47)	(355,121)		$ 2				$ 0
Ending Balance (in shares) at Mar. 31, 2019		75,333,254					2,093,155				2,400
Beginning Balance at Dec. 31, 2019	69,764	$ 96	436,306	(47)	(366,593)		$ 2				$ 0
Beginning Balance (in shares) at Dec. 31, 2019		96,189,074					2,093,155				618
Stock-based compensation	1,520		1,520
Stock option exercises	$ 338		338
Stock option exercises (in shares)	107,287	107,287
Restricted stock awards	$ 0
Restricted stock awards (in shares)		459,670
Series B conversion to common stock						$ (1)	$ 2	$ 2	$ (1)	$ 1		$ 1
Series B conversion to common stock (in shares)		972,222					(2,093,155)	2,093,155		175	175	972,222
Net income (loss)	4,966				4,966
Ending Balance at Mar. 31, 2020	$ 76,588	$ 99	$ 438,163	$ (47)	$ (361,627)		$ 0				$ 0
Ending Balance (in shares) at Mar. 31, 2020		99,821,408					0				443