Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2018	$ 39,001	$ 1,597	$ 314,907	$ (276,800)	$ (703)
Balance, shares at Dec. 31, 2018		159,721,000
Issuance of common stock	7,785	$ 23	7,762
Issuance of common stock, shares		2,307,000
Common stock issued under equity compensation plan, net of shares withheld for taxes	(408)	$ 3	(411)
Common stock issued under equity compensation plan, net of shares withheld for taxes, shares		288,000
Exercise of options	350	$ 2	348
Exercise of options, shares		212,000
Share-based compensation	1,366		1,366
Cumulative effect of change in accounting principle	116			116
Net loss	(5,539)			(5,539)
Other comprehensive income (loss)	(3)				(3)
Balance at Mar. 31, 2019	42,668	$ 1,625	323,972	(282,223)	(706)
Balance, shares at Mar. 31, 2019		162,528,000
Balance at Dec. 31, 2019	54,500	$ 1,652	332,377	(278,827)	(702)
Balance, shares at Dec. 31, 2019		165,221,000
Common stock issued under equity compensation plan, net of shares withheld for taxes	(597)	$ 2	(599)
Common stock issued under equity compensation plan, net of shares withheld for taxes, shares		218,000
Exercise of options	271	$ 2	269
Exercise of options, shares		121,000
Share-based compensation	1,978		1,978
Net loss	(2,356)			(2,356)
Other comprehensive income (loss)	2				2
Balance at Mar. 31, 2020	$ 53,798	$ 1,656	$ 334,025	$ (281,183)	$ (700)
Balance, shares at Mar. 31, 2020		165,560,000