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 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	3,978		3,978
Stock option exercises	1,193		1,193
Stock option exercises (in shares)		412,500
Restricted stock awards	0	$ 1	(1)
Restricted stock awards (in shares)		801,661
Conversion to common stock									$ 0		$ 8	$ (8)
Conversion to common stock (in shares)										(1,402)	7,788,888
Equity offering, net of finance costs	47,590	$ 10	47,580
Equity offering, net of finance costs (in shares)		10,000,000
Net income (loss)	(14,609)				(14,609)
Ending Balance at Sep. 30, 2019	67,894	$ 90	433,746	(47)	(365,897)		$ 2			$ 0
Ending Balance (in shares) at Sep. 30, 2019		89,796,774					2,093,155			1,698
Beginning Balance at Jun. 30, 2019	66,150	$ 88	432,358	(47)	(366,251)		$ 2			$ 0
Beginning Balance (in shares) at Jun. 30, 2019		89,535,024					2,093,155			1,716
Stock-based compensation	1,267		1,267
Stock option exercises	123		123
Stock option exercises (in shares)		52,121
Restricted stock awards	0	$ 2	(2)
Restricted stock awards (in shares)		109,629
Conversion to common stock									0
Conversion to common stock (in shares)										(18)	100,000
Net income (loss)	354				354
Ending Balance at Sep. 30, 2019	67,894	$ 90	433,746	(47)	(365,897)		$ 2			$ 0
Ending Balance (in shares) at Sep. 30, 2019		89,796,774					2,093,155			1,698
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	7,845		7,845
Stock option exercises	$ 2,761	$ 1	2,760
Stock option exercises (in shares)	1,159,347	1,159,347
Restricted stock awards	$ 0
Restricted stock awards (in shares)		712,654
Conversion to common stock						$ 0	$ (2)	$ 2	$ 0		$ 1	$ (1)
Conversion to common stock (in shares)							(2,093,155)	2,093,155		(175)	972,222
Net income (loss)	15,515				15,515
Ending Balance at Sep. 30, 2020	95,885	$ 100	446,910	(47)	(351,078)		$ 0			$ 0
Ending Balance (in shares) at Sep. 30, 2020		101,126,452					0			443
Beginning Balance at Jun. 30, 2020	84,770	$ 99	445,180	(47)	(360,462)		$ 0			$ 0
Beginning Balance (in shares) at Jun. 30, 2020		100,916,511					0			443
Stock-based compensation	1,539		1,539
Stock option exercises	192	$ 1	191
Stock option exercises (in shares)		68,623
Restricted stock awards	0
Restricted stock awards (in shares)		141,318
Net income (loss)	9,384				9,384
Ending Balance at Sep. 30, 2020	$ 95,885	$ 100	$ 446,910	$ (47)	$ (351,078)		$ 0			$ 0
Ending Balance (in shares) at Sep. 30, 2020		101,126,452					0			443