UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($)	Total	Common Stock	Preferred Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)
Balance, shares at Dec. 31, 2019		13,146,831
Balance, amount at Dec. 31, 2019	$ 21,096,000	$ 13,000	$ 0	$ 364,028,000	$ (342,945,000)
Share-based compensation	1,028,000	0	0	1,028,000	0
Net loss	(5,435,000)	$ 0	0	0	(5,435,000)
Balance, shares at Jun. 30, 2020		13,146,831
Balance, amount at Jun. 30, 2020	16,689,000	$ 13,000	$ 0	365,056,000	(348,380,000)
Balance, shares at Mar. 31, 2020		13,146,831	0
Balance, amount at Mar. 31, 2020	17,544,000	$ 13,000	$ 0	364,537,000	(347,006,000)
Share-based compensation	519,000	0	0	519,000	0
Net loss	(1,374,000)	$ 0	0	0	(1,374,000)
Balance, shares at Jun. 30, 2020		13,146,831
Balance, amount at Jun. 30, 2020	16,689,000	$ 13,000	0	365,056,000	(348,380,000)
Balance, shares at Dec. 31, 2020		13,169,204
Balance, amount at Dec. 31, 2020	16,335,000	$ 13,000	0	366,087,000	(349,765,000)
Share-based compensation	924,000	$ 0	0	924,000	0
Net loss	$ 6,000
Issuance of common stock upon exercise of stock options, shares	76,667	76,667
Issuance of common stock upon exercise of stock options, amount	$ 176,000	$ 0	0	176,000	0
Issuance of restricted stock, shares		220,000
Issuance of restricted stock, amount	0	$ 0	0	0	0
Net income	6,000	$ 0	0	0	6,000
Balance, shares at Jun. 30, 2021		13,465,871
Balance, amount at Jun. 30, 2021	17,441,000	$ 13,000	0	367,187,000	(349,759,000)
Balance, shares at Mar. 31, 2021		13,443,909
Balance, amount at Mar. 31, 2021	17,270,000	$ 13,000	0	366,712,000	(349,455,000)
Share-based compensation	425,000	0	0	425,000	0
Net loss	(304,000)	$ 0	0	0	(304,000)
Issuance of common stock upon exercise of stock options, shares		21,962
Issuance of common stock upon exercise of stock options, amount	50,000	$ 0	0	50,000	0
Balance, shares at Jun. 30, 2021		13,465,871
Balance, amount at Jun. 30, 2021	$ 17,441,000	$ 13,000	$ 0	$ 367,187,000	$ (349,759,000)