SHAREHOLDERS EQUITY - Common Stock (Details) $ / shares in Units, $ in Thousands				9 Months Ended
	Sep. 10, 2018 shares	Jul. 26, 2018 USD ($) shares	Jul. 23, 2018 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) item $ / shares shares	Sep. 30, 2017 USD ($) item shares	Dec. 31, 2017 $ / shares shares
Class of Stock [Line Items]
Common stock par value | $ / shares				$ 0		$ 0
Issuance of common stock, net of issuance costs | $				$ 34,450	$ 3,860
Common stock issuance costs | $				$ 4,411	$ 43
Preferred Stock, shares outstanding						20,868
Convertible Preferred Stock Converted to Other Securities | $		$ 25,000
Series A preferred stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding		8,559
Series B preferred stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding		428
Series C preferred stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding		11,881
Series D
Class of Stock [Line Items]
Preferred Stock, shares outstanding		41,000				41,000
Common Stock
Class of Stock [Line Items]
Common stock par value | $ / shares				$ 0.00
Number of votes per each share				one
Make whole share issuance	128,978
Common Stock | Private Placement
Class of Stock [Line Items]
Issuance of common stock (in shares)				67,242	13,579
Number of Private Placement Memorandums | item				2	2
Issuance of common stock, net of issuance costs | $				$ 1,900	$ 400
Common stock issuance costs | $				$ 100
Common Stock | IPO
Class of Stock [Line Items]
Issuance of common stock (in shares)			1,921,775
Issuance of common stock, net of issuance costs | $			$ 32,500
Common stock price (in dollars per share) | $ / shares			$ 19.00
Common Stock | Underwriters option
Class of Stock [Line Items]
Issuance of common stock (in shares)			296,250