Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2018	$ 1	$ 223,440	$ (207,330)	$ 16,111
Beginning Balance, (in shares) at Dec. 31, 2018	310,330
Share-based compensation expense		135		$ 135
Issuance of common stock upon vesting of restricted stock units (in shares)	48			48
Issuance of common stock under ESPP		1		$ 1
Issuance of common stock under ESPP (in shares)	36
Net loss			(5,779)	(5,779)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2019	$ 1	223,576	(213,109)	10,468
Ending Balance, (in shares) at Jun. 30, 2019	310,414
Stockholders' Equity Attributable to Parent, Beginning Balance at Mar. 31, 2019	$ 1	223,508	(209,965)	13,544
Beginning Balance, (in shares) at Mar. 31, 2019	310,393
Share-based compensation expense		68		$ 68
Issuance of common stock upon vesting of restricted stock units (in shares)	21			21
Net loss			(3,144)	$ (3,144)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2019	$ 1	223,576	(213,109)	10,468
Ending Balance, (in shares) at Jun. 30, 2019	310,414
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2019	$ 2	224,741	(219,160)	$ 5,583
Beginning Balance, (in shares) at Dec. 31, 2019	550,736			550,736
Share-based compensation expense		115		$ 115
Issuance of common stock upon vesting of restricted stock units (in shares)	50			50
Issuance of common stock under ESPP (in shares)	0
Fractional shares issued due to reverse stock split	7,692
Issuance of common stock in public offerings		8,592		$ 8,592
Issuance of common stock in public offerings (in shares)	2,670,853
Issuance of common stock upon exercise of warrants		343		343
Issuance of common stock upon exercise of warrants (in shares)	1,653,089
Net loss			(4,603)	(4,603)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2020	$ 2	233,791	(223,763)	$ 10,030
Ending Balance, (in shares) at Jun. 30, 2020	4,882,420			4,882,420
Stockholders' Equity Attributable to Parent, Beginning Balance at Mar. 31, 2020	$ 2	231,132	(221,574)	$ 9,560
Beginning Balance, (in shares) at Mar. 31, 2020	2,571,553
Share-based compensation expense		45		$ 45
Issuance of common stock upon vesting of restricted stock units (in shares)	50			50
Issuance of common stock in public offerings		2,557		$ 2,557
Issuance of common stock in public offerings (in shares)	1,715,240
Issuance of common stock upon exercise of warrants		57		57
Issuance of common stock upon exercise of warrants (in shares)	595,577
Net loss			(2,189)	(2,189)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2020	$ 2	$ 233,791	$ (223,763)	$ 10,030
Ending Balance, (in shares) at Jun. 30, 2020	4,882,420			4,882,420