Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member] Series A Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2017	22,000	17,674,729
Balance at Dec. 31, 2017	$ 21,523	$ 18	$ 202,953	$ (189,741)	$ (14)	$ 34,739
Stock-based compensation expense			821			821
Other comprehensive gain/(loss)					10	10
Net loss				(6,081)		(6,081)
Issuance of common stock upon ESPP purchase
Balance (in shares) at Mar. 31, 2018	22,000	17,674,729
Balance at Mar. 31, 2018	$ 21,523	$ 18	203,774	(195,822)	(4)	29,489
Balance (in shares) at Dec. 31, 2017	22,000	17,674,729
Balance at Dec. 31, 2017	$ 21,523	$ 18	202,953	(189,741)	(14)	34,739
Net loss						(15,470)
Balance (in shares) at Sep. 30, 2018	22,000	19,221,292
Balance at Sep. 30, 2018	$ 21,523	$ 19	208,536	(205,211)	4	24,871
Balance (in shares) at Mar. 31, 2018	22,000	17,674,729
Balance at Mar. 31, 2018	$ 21,523	$ 18	203,774	(195,822)	(4)	29,489
Stock-based compensation expense			922			922
Other comprehensive gain/(loss)					5	5
Net loss				(4,879)		(4,879)
Issuance of common stock upon ESPP purchase			84			84
Issuance of common stock upon ESPP purchase (in shares)		51,984
Balance (in shares) at Jun. 30, 2018	22,000	17,726,713
Balance at Jun. 30, 2018	$ 21,523	$ 18	204,780	(200,701)	1	25,621
Stock-based compensation expense			904			904
Other comprehensive gain/(loss)					3	3
Net loss				(4,510)		(4,510)
Issuance of common stock upon ESPP purchase
Issuance of common stock upon ESPP purchase (in shares)
Issuance of common stock, net of issuance costs (in shares)		1,494,579
Issuance of common stock, net of issuance costs		$ 1	2,852			2,853
Balance (in shares) at Sep. 30, 2018	22,000	19,221,292
Balance at Sep. 30, 2018	$ 21,523	$ 19	208,536	(205,211)	4	24,871
Balance (in shares) at Dec. 31, 2018	22,000	19,243,651
Balance at Dec. 31, 2018	$ 21,523	$ 19	209,366	(210,470)	5	20,443
Conversion of Series A convertible preferred stock into Common Stock (in shares)	(340)
Conversion of Series A convertible preferred stock into Common Stock	$ (340)
Conversion of Series A convertible preferred stock into Common Stock (in shares)		341,743
Conversion of Series A convertible preferred stock into Common Stock			340
Stock-based compensation expense			780			780
Other comprehensive gain/(loss)					(2)	(2)
Net loss				(6,531)		(6,531)
Balance (in shares) at Mar. 31, 2019	21,660	19,585,394
Balance at Mar. 31, 2019	$ 21,183	$ 19	210,486	(217,001)	3	14,690
Balance (in shares) at Dec. 31, 2018	22,000	19,243,651
Balance at Dec. 31, 2018	$ 21,523	$ 19	209,366	(210,470)	5	20,443
Net loss						(13,382)
Balance (in shares) at Sep. 30, 2019	21,660	19,585,394
Balance at Sep. 30, 2019	$ 21,183	$ 19	210,683	(223,852)	2	8,035
Balance (in shares) at Mar. 31, 2019	21,660	19,585,394
Balance at Mar. 31, 2019	$ 21,183	$ 19	210,486	(217,001)	3	14,690
Conversion of Series A convertible preferred stock into Common Stock
Conversion of Series A convertible preferred stock into Common Stock
Stock-based compensation expense			101			101
Other comprehensive gain/(loss)					1	1
Net loss				(5,315)		(5,315)
Balance (in shares) at Jun. 30, 2019	21,660	19,585,394
Balance at Jun. 30, 2019	$ 21,183	$ 19	210,587	(222,316)	4	9,477
Conversion of Series A convertible preferred stock into Common Stock
Conversion of Series A convertible preferred stock into Common Stock
Stock-based compensation expense			96			96
Other comprehensive gain/(loss)					(2)	(2)
Net loss				(1,536)		(1,536)
Balance (in shares) at Sep. 30, 2019	21,660	19,585,394
Balance at Sep. 30, 2019	$ 21,183	$ 19	$ 210,683	$ (223,852)	$ 2	$ 8,035