Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Deficit	Preferred Stock Series A	Preferred Stock Series A Preferred Stock	Preferred Stock Series A Common Stock	Preferred Stock Series A Additional Paid-In Capital	Preferred Stock Series B	Preferred Stock Series B Preferred Stock	Preferred Stock Series B Common Stock	Preferred Stock Series B 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	2,711		2,711
Stock option exercises	1,070		1,070
Stock option exercises (in shares)		360,379
Restricted stock awards	0	$ (1)	1
Restricted stock awards (in shares)		692,032
Series B conversion to common stock										$ 0		$ 8	$ (8)
Series B conversion to common stock (in shares)											1,384	7,688,888
Equity offering, net of finance costs (in shares)												10,000,000
Equity offering, net of finance costs										47,590		$ 10	47,580
Net income	(14,963)				(14,963)
Ending Balance at Jun. 30, 2019	66,150	$ 88	432,358	(47)	(366,251)		$ 2				$ 0
Ending Balance (in shares) at Jun. 30, 2019		89,535,024					2,093,155				1,716
Beginning Balance at Mar. 31, 2019	27,522	$ 74	382,614	(47)	(355,121)		$ 2				$ 0
Beginning Balance (in shares) at Mar. 31, 2019		75,333,254					2,093,155				2,400
Stock-based compensation	1,570		1,570
Stock option exercises	598		598
Stock option exercises (in shares)		210,104
Restricted stock awards	0
Restricted stock awards (in shares)		191,666
Series B conversion to common stock										0		$ 4	(4)
Series B conversion to common stock (in shares)											684	3,800,000
Equity offering, net of finance costs (in shares)												10,000,000
Equity offering, net of finance costs										47,590		$ 10	$ 47,580
Net income	(11,130)				(11,130)
Ending Balance at Jun. 30, 2019	66,150	$ 88	432,358	(47)	(366,251)		$ 2				$ 0
Ending Balance (in shares) at Jun. 30, 2019		89,535,024					2,093,155				1,716
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	6,306		6,306
Stock option exercises	$ 2,569	$ 0	2,569
Stock option exercises (in shares)	1,090,724	1,090,724
Restricted stock awards	$ 0	$ 0
Restricted stock awards (in shares)		571,336
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
Equity offering, net of finance costs (in shares)						0
Net income	6,131				6,131
Ending Balance at Jun. 30, 2020	84,770	$ 99	445,180	(47)	(360,462)		$ 0				$ 0
Ending Balance (in shares) at Jun. 30, 2020		100,916,511					0				443
Beginning Balance at Mar. 31, 2020	76,588	$ 99	438,163	(47)	(361,627)		$ 0				$ 0
Beginning Balance (in shares) at Mar. 31, 2020		99,821,408					0				443
Stock-based compensation	4,786		4,786
Stock option exercises	2,231	$ 0	2,231
Stock option exercises (in shares)		983,437
Restricted stock awards	0	$ 0
Restricted stock awards (in shares)		111,666
Net income	1,165				1,165
Ending Balance at Jun. 30, 2020	$ 84,770	$ 99	$ 445,180	$ (47)	$ (360,462)		$ 0				$ 0
Ending Balance (in shares) at Jun. 30, 2020		100,916,511					0				443