Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Beginning balance, shares at Dec. 31, 2017	44,181
Beginning balance, value at Dec. 31, 2017	$ 0	$ 80,384	$ (78,551)	$ 1,833
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares	7,910
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, value		1,312		1,312
Issuance of common stock and warrants in connection with registered direct offering and private placement, net of offering costs, shares	27,465
Issuance of common stock and warrants in connection with registered direct offering and private placement, net of offering costs, value		4,210		4,210
Issuance of common stock, pre-funded warrants and warrants in connection with underwritten public offering, net of offering costs, shares	67,740
Issuance of common stock, pre-funded warrants and warrants in connection with underwritten public offering, net of offering costs, value		13,193		13,193
Issuance of common stock upon the exercise of pre-funded warrants, shares	191,532
Issuance of common stock upon the exercise of pre-funded warrants, value		105		105
Issuance of common stock under the employee stock purchase plan, shares	53
Issuance of common stock under the employee stock purchase plan, value		3		3
Issuance of restricted stock, shares	3,697
Stock-based compensation expense		282		282
Net Loss			(7,360)	(7,360)
Ending balance, shares at Dec. 31, 2018	342,578
Ending balance, value at Dec. 31, 2018	$ 0	99,489	(85,911)	13,578
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares	9,090
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, value		(58)		(58)
Issuance of common stock in connection with registered direct public, net of offering costs, shares	181,818
Issuance of common stock in connection with registered direct public, net of offering costs, value	$ 1	765		766
Issuance of common stock upon the exercise of pre-funded warrants, shares	130,338
Issuance of common stock upon the exercise of pre-funded warrants, value		$ 72		$ 72
Issuance of common stock under the employee stock purchase plan, shares	36	1		1
Issuance of common stock upon vesting of restricted stock units, shares	1,154
Issuance of common stock upon vesting of restricted stock units, value		$ (3)		$ (3)
Issuance of restricted stock, shares	4,419
Stock-based compensation expense		300		300
Net Loss			(8,908)	(8,908)
Ending balance, shares at Dec. 31, 2019	669,433
Ending balance, value at Dec. 31, 2019	$ 1	$ 100,566	$ (94,819)	$ 5,748