STOCKHOLDERS' EQUITY AND LOSS PER SHARE (Details) - USD ($)			3 Months Ended			6 Months Ended		12 Months Ended
	Apr. 06, 2018	Mar. 27, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Nov. 26, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			100,000,000			100,000,000		47,000,000
New shares issued (in shares)						0
Net proceeds from units issued in the period				$ 2,809,000	$ 18,381,000
Preferred stock, shares authorized (in shares)			3,000,000			3,000,000		3,000,000
Loss Per Share
Total shares excluded from net loss per share attributable to common stockholders						6,266,706	6,683,300
Common stock warrants
Class of Stock [Line Items]
Class of Warrant or Right, Outstanding			2,256,537	3,391,100		2,256,537	3,391,100	3,385,100		3,730,255
Loss Per Share
Total shares excluded from net loss per share attributable to common stockholders							3,391,100
Common stock options
Stock Repurchase Program [Abstract]
Shares authorized, amount									$ 4,000,000.0
Stock repurchased during period								$ 152,000
Stock repurchased during period (in shares)			0			0
Loss Per Share
Total shares excluded from net loss per share attributable to common stockholders						1,356,028	1,129,653
Non-vested restricted stock unit awards
Loss Per Share
Total shares excluded from net loss per share attributable to common stockholders						2,654,141	2,162,547
Common stock options
Class of Stock [Line Items]
New shares issued (in shares)		5,714,286		857,142	5,714,286
Share price (in dollars per share)		$ 3.50
Net proceeds from the sale of common stock from private placement offering		$ 20,000,000
Net proceeds from units issued in the period		$ 18,400,000		$ 1,000	$ 6,000
Over-Allotment Option | Common stock options
Class of Stock [Line Items]
New shares issued (in shares)	857,142
Share price (in dollars per share)	$ 3.50
Net proceeds from the sale of common stock from private placement offering	$ 3,000,000
Net proceeds from units issued in the period	$ 2,800,000