Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member]	Preferred Stock [Member] Series G Preferred Stock [Member]	Common Stock [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2017	$ 313		$ 279,548	$ (265,128)	$ 14,733
Balance (in shares) at Dec. 31, 2017		630	18,046,731
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock awards under equity incentive plans	0		$ 790	0	790
Common stock awards under equity incentive plans (in shares)		0	312,556
Exercise of options	0		$ 28	0	28
Exercise of options (in shares)		0	32,500
Conversion of preferred stock into common stock	(112)		$ 112	0	0
Conversion of preferred stock into common stock (in shares)		(225)	213,523
Exercise of warrant	0		$ 11,106	0	11,106
Exercise of warrant (in shares)		0	8,826,230
Acquisition of Golden Ridge	0		$ 5,000	0	5,000
Acquisition of Golden Ridge (in shares)		0	1,666,667
Other	0		$ 155	0	155
Other (in shares)		0	0
Net loss	0		$ 0	(8,101)	(8,101)
Balance at Dec. 31, 2018	201		$ 296,739	(273,229)	$ 23,711
Balance (in shares) at Dec. 31, 2018		405	29,098,207		29,098,207
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sales of common stock and Prefunded Warrant, net of costs	0		$ 19,422	0	$ 19,422
Sales of common stock and Prefunded Warrant, net of costs (in shares)		0	9,831,668
Exercise of Prefunded Warrant	0		$ 10	0	10
Exercise of Prefunded Warrant (in shares)		0	1,003,344
Common stock awards under equity incentive plans	0		$ 1,360	0	1,360
Common stock awards under equity incentive plans (in shares)		0	289,349
Exercise of options	0		$ 156	0	156
Exercise of options (in shares)		0	165,812
Conversion of preferred stock into common stock	(89)		$ 89	0	0
Conversion of preferred stock into common stock (in shares)		(180)	170,818
Exercise of warrant	0		$ 2,062	0	2,062
Exercise of warrant (in shares)		0	685,409
Retirement of unvested shares	0		$ 0	0	0
Retirement of unvested shares (in shares)		0	(830,124)
Retirement of shares received in settlement with sellers of Golden Ridge	0		$ (1,027)	0	(1,027)
Retirement of shares received in settlement with sellers of Golden Ridge (in shares)		0	(340,000)
Net loss	0		$ 0	(13,951)	(13,951)
Balance at Dec. 31, 2019	$ 112		$ 318,811	$ (287,180)	$ 31,743
Balance (in shares) at Dec. 31, 2019		225	40,074,483		40,474,483