Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Beginning balance, shares at Dec. 31, 2017	2,429,993
Beginning balance, value at Dec. 31, 2017	$ 0	$ 80,384	$ (78,551)	$ 1,833
Cash paid in lieu of fractional shares for 1:10 reverse stock split	(31)
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares	270,000
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, value		932		932
Stock-based compensation expense		41		41
Net Loss			(2,239)	(2,239)
Ending balance, shares at Mar. 31, 2018	2,699,962
Ending balance, value at Mar. 31, 2018		81,357	(80,790)	567
Beginning balance, shares at Dec. 31, 2017	2,429,993
Beginning balance, value at Dec. 31, 2017	$ 0	80,384	(78,551)	1,833
Net Loss				(5,633)
Ending balance, shares at Sep. 30, 2018	4,449,909
Ending balance, value at Sep. 30, 2018		85,934	(84,184)	1,750
Beginning balance, shares at Mar. 31, 2018	2,699,962
Beginning balance, value at Mar. 31, 2018		81,357	(80,790)	567
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares	150,000
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, value		359		359
Issuance of common stock and warrants in connection with registered direct offering and private placement, net of offering costs, shares	1,510,604
Issuance of common stock and warrants in connection with registered direct offering and private placement, net of offering costs, value		4,210		4,210
Stock-based compensation expense		37		37
Net Loss			(1,901)	(1,901)
Ending balance, shares at Jun. 30, 2018	4,360,566
Ending balance, value at Jun. 30, 2018		85,963	(82,691)	3,272
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares	15,000
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, value		21		21
Issuance of common stock under the employee stock purchase plan, shares	756
Issuance of common stock under the employee stock purchase plan, value		1		1
Issuance of common stock, pre-funded warrants and warrants in connection with underwritten public offering, net of offering costs, value		(90)		(90)
Issuance of restricted stock, shares	73,587
Stock-based compensation expense		39		39
Net Loss			(1,493)	(1,493)
Ending balance, shares at Sep. 30, 2018	4,449,909
Ending balance, value at Sep. 30, 2018		85,934	(84,184)	1,750
Beginning balance, shares at Dec. 31, 2018	18,841,814
Beginning balance, value at Dec. 31, 2018	$ 2	99,487	(85,911)	13,578
Issuance of common stock upon the exercise of pre-funded warrants, shares	4,304,286
Issuance of common stock upon the exercise of pre-funded warrants, value		43		43
Issuance of restricted stock, shares	243,032
Stock-based compensation expense		160		160
Net Loss			(2,119)	(2,119)
Ending balance, shares at Mar. 31, 2019	23,389,132
Ending balance, value at Mar. 31, 2019	$ 2	99,690	(88,030)	11,662
Beginning balance, shares at Dec. 31, 2018	18,841,814
Beginning balance, value at Dec. 31, 2018	$ 2	99,487	(85,911)	13,578
Net Loss				(6,248)
Ending balance, shares at Sep. 30, 2019	25,654,670
Ending balance, value at Sep. 30, 2019	$ 3	99,761	(92,159)	7,605
Beginning balance, shares at Mar. 31, 2019	23,389,132
Beginning balance, value at Mar. 31, 2019	$ 2	99,690	(88,030)	11,662
Issuance of common stock upon the exercise of pre-funded warrants, shares	1,700,000
Issuance of common stock upon the exercise of pre-funded warrants, value	$ 1	16		17
Issuance of common stock under the employee stock purchase plan, shares	2,065
Issuance of common stock under the employee stock purchase plan, value		1		1
Stock-based compensation expense		62		62
Net Loss			(2,035)	(2,035)
Ending balance, shares at Jun. 30, 2019	25,091,197
Ending balance, value at Jun. 30, 2019	$ 3	99,769	(90,065)	9,707
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares	500,000
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, value		(52)		(52)
Issuance of common stock upon vesting of restricted stock units, shares	63,473
Issuance of common stock upon vesting of restricted stock units, value		(3)		(3)
Stock-based compensation expense		47		47
Net Loss			(2,094)	(2,094)
Ending balance, shares at Sep. 30, 2019	25,654,670
Ending balance, value at Sep. 30, 2019	$ 3	$ 99,761	$ (92,159)	$ 7,605