Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Conversion of CRG into Series A Preferred Stock [Member] Preferred Stock [Member]	Conversion of CRG into Series A Preferred Stock [Member] Common Stock [Member]	Conversion of CRG into Series A Preferred Stock [Member] Additional Paid-in Capital [Member]	Conversion of CRG into Series A Preferred Stock [Member] Retained Earnings [Member]	Conversion of CRG into Series A Preferred Stock [Member]	Conversion of Series B Preferred Stock into Common Stock [Member] Preferred Stock [Member]	Conversion of Series B Preferred Stock into Common Stock [Member] Common Stock [Member]	Conversion of Series B Preferred Stock into Common Stock [Member] Additional Paid-in Capital [Member]	Conversion of Series C Preferred Stock into Common Stock [Member] Preferred Stock [Member]	Conversion of Series C Preferred Stock into Common Stock [Member] Common Stock [Member]	Conversion of Series C Preferred Stock into Common Stock [Member] Additional Paid-in Capital [Member]	Conversion of Series C Preferred Stock into Common Stock [Member] Retained Earnings [Member]	Conversion of Series C Preferred Stock into Common Stock [Member]	Series B Preferred Stock [Member] Preferred Stock [Member]	Series B Preferred Stock [Member] Additional Paid-in Capital [Member]	Series B Preferred Stock [Member]	Series A Preferred Stock [Member] Preferred Stock [Member]	Series A Preferred Stock [Member] Common Stock [Member]	Series A Preferred Stock [Member] Additional Paid-in Capital [Member]	Series A Preferred Stock [Member] Retained Earnings [Member]	Series A Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2017																							833,597
Balance at Dec. 31, 2017																							$ 1	$ 265,636	$ (301,327)	$ (35,690)
Issuance of common stock (in shares)																							42,127
Issuance of common stock																								337		337
Employee stock-based compensation																								618		618
Conversion of converitble securities (in shares)	41,800					(7,017)	3,508,500
Conversion of converitble securities			$ 41,800		$ 41,800		$ 2	$ (2)
Issuance of common stock (in shares)														17,979
Issuance of stock															$ 15,525	$ 15,525
Accretion of Series A Preferred Stock dividends																								(410)		(410)
Net and comprehensive loss																									(10,281)	(10,281)
Balance (in shares) at Mar. 31, 2018																						52,762	4,384,224
Balance at Mar. 31, 2018																							$ 3	323,504	(311,608)	11,899
Balance (in shares) at Dec. 31, 2018																						45,671	34,921,999
Balance at Dec. 31, 2018																							$ 34	338,311	(328,885)	9,460
Employee stock-based compensation																								493		493
Conversion of converitble securities (in shares)						(1,523)	3,807,500		(2,170)	5,425,000
Conversion of converitble securities							$ 4	$ (4)		$ 5	$ (5)
Accretion of Series A Preferred Stock dividends																								(895)		(895)
Net and comprehensive loss																									(5,055)	(5,055)
Stock Issued During Period, Shares, Employee Stock Purchase Plans																							46,888
Issuance of common stock under officers and directors purchase plan																								18		18
Exercises of warrants for common stock (in shares)																							15,851,605
Exercises of warrants for common stock																							$ 16	6,324		6,340
Issuance of Series A preferred stock to pay dividends (in shares)																	2,945
Issuance of Series A preferred stock to pay dividends																			$ 2,918		$ 2,918
Balance (in shares) at Mar. 31, 2019																						44,923	60,052,992
Balance at Mar. 31, 2019																							$ 59	$ 347,160	$ (333,940)	$ 13,279