STOCKHOLDERS' EQUITY - SALES AGREEMENT (Details) - USD ($)		1 Months Ended	12 Months Ended
	Aug. 28, 2015	Dec. 31, 2017	Dec. 31, 2017
Stockholders Equity Note [Abstract]
Aggregate offering price of common stock	$ 50,000,000
Maximum commission rate (as a percent)	3.00%
Issuance of common stock in connection with at market offering, net of issuance costs (in shares)		614,230
Net cash proceeds from issuance of common stock after deducting sales commissions and offering costs		$ 1,060,000	$ 1,060,000