Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2018	$ 56,615	$ 50	$ 12	$ 162,428	$ (105,875)
Balance, shares at Dec. 31, 2018		10	11,891
Exercise of stock options	99	$ 0	$ 0	99	0
Exercise of stock options, shares		0	10
Issuance of restricted common stock	0	$ 0	$ 0	0	0
Issuance of restricted common stock, shares		0	255
Forfeiture of restricted common stock	0	$ 0	$ 0	0	0
Forfeiture of restricted common stock, shares		0	(1)
Purchase and retirement of common stock	(486)	$ 0	$ 0	(486)	0
Purchase and retirement of common stock, shares		0	(20)
Stock-based compensation	2,078	$ 0	$ 0	2,078	0
Net loss	(8,463)	0	0	0	(8,463)
Balance at Mar. 31, 2019	49,843	$ 50	$ 12	164,119	(114,338)
Balance, shares at Mar. 31, 2019		10	12,135
Balance at Dec. 31, 2019	49,450	$ 50	$ 12	188,103	(138,715)
Balance, shares at Dec. 31, 2019		10	12,446
Issuance of common stock, net of issuance costs	574	$ 0	$ 1	573	0
Issuance of common stock, net of issuance costs, shares		0	28
Exercise of stock options	$ 135	$ 0	$ 0	135	0
Exercise of stock options, shares	8	0	8
Issuance of restricted common stock	$ 0	$ 0	$ 0	0	0
Issuance of restricted common stock, shares		0	186
Forfeiture of restricted common stock	0	$ 0	$ 0	0	0
Forfeiture of restricted common stock, shares		0	0
Purchase and retirement of common stock	(738)	$ 0	$ 0	(738)	0
Purchase and retirement of common stock, shares		0	(23)
Stock-based compensation	2,230	$ 0	$ 0	2,230	0
Net loss	(8,908)	0	0	0	(8,908)
Balance at Mar. 31, 2020	$ 42,743	$ 50	$ 13	$ 190,303	$ (147,623)
Balance, shares at Mar. 31, 2020		10	12,645