SHAREHOLDERS' EQUITY (Details) - USD ($)		3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 10, 2016	Dec. 31, 2016	Sep. 30, 2017	Sep. 30, 2017
Class of Stock [Line Items]
Payments of stock issuance costs				$ 300,000
Cowen
Class of Stock [Line Items]
At-the-market sales agreement, maximum aggregate proceeds	$ 25,000,000.0
At-the-market sales agreement, proceeds from issuance of common stock		$ 6,700,000
Amount of net capacity remaining on the at-the-market sales agreement			$ 17,200,000	$ 17,200,000
Cowen | Common Class A
Class of Stock [Line Items]
At-the-market sales agreement, shares issued (in shares)			1,864,384	2,222,240
Cowen | Maximum
Class of Stock [Line Items]
Percentage of gross proceeds payable as commission	3.00%