CAPITAL STOCK - Narrative (Details) $ / shares in Units, $ in Thousands				1 Months Ended						12 Months Ended		34 Months Ended
	Mar. 13, 2020 shares	Oct. 31, 2019 USD ($) $ / shares shares	Mar. 31, 2017	Feb. 29, 2020 USD ($) $ / shares shares	Jan. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 $ / shares shares	Aug. 31, 2018 USD ($) closing $ / shares shares	Feb. 28, 2018 USD ($) $ / shares shares	Mar. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Class of Stock [Line Items]
Shares authorized (in shares)						105,000,000				105,000,000		105,000,000
Common stock, shares authorized (in shares)						100,000,000				100,000,000	100,000,000	100,000,000
Preferred stock, shares authorized (in shares)						5,000,000				5,000,000		5,000,000
Common stock, par value (in dollars per share) | $ / shares						$ 0.01				$ 0.01	$ 0.01	$ 0.01
Shares sold (in shares)										2,557,544
Proceeds from the sale of common stock | $										$ 2,283	$ 44,529
Preferred stock outstanding (in shares)						0				0		0
Aspire Stock Purchase Agreement
Class of Stock [Line Items]
Amount of shares authorized to be sold (in shares)						20,000,000
Sale of stock, term						30 months
Shares sold (in shares)										1,598,465
Sale price (in usd per share) | $ / shares						$ 0.63				$ 0.63		$ 0.63
Transaction value | $										$ 1,000
Average over number of lowest sale prices						3 days
Number of consecutive days threshold						10 days
LLS Stock Purchase Agreement
Class of Stock [Line Items]
Amount of shares authorized to be sold (in shares)							5,000,000
Shares sold (in shares)		606,364					150,987
Sale price (in usd per share) | $ / shares		$ 0.82					$ 6.62
Transaction value | $							$ 5,000
Average over number of lowest sale prices							3 days
Number of separate closings | closing							5
Aggregate offering | $		$ 1,400
ATM Agreement
Class of Stock [Line Items]
Commission fee percent			3.00%
Underwriter Option
Class of Stock [Line Items]
Shares sold (in shares)								7,414,996
Proceeds from the sale of common stock | $								$ 37,900
Underwriting Agreement
Class of Stock [Line Items]
Sale price (in usd per share) | $ / shares								$ 5.50
Maximum | ATM Agreement
Class of Stock [Line Items]
Aggregate offering | $									$ 50,000
Common Stock | Aspire Stock Purchase Agreement
Class of Stock [Line Items]
Amount of shares required to be purchased (in shares)						200,000
Common Stock | ATM Agreement
Class of Stock [Line Items]
Shares sold (in shares)										658,000		1,871,386
Weighted-average share price (in usd per share) | $ / shares										$ 1.19		$ 6.09
Proceeds from the sale of common stock | $										$ 800		$ 11,000
Subsequent event | Aspire Stock Purchase Agreement
Class of Stock [Line Items]
Amount of shares authorized to be sold (in shares)	14,900,000
Shares sold (in shares)					2,200,000
Transaction value | $					$ 4,100
Weighted-average share price (in usd per share) | $ / shares					$ 1.84
Subsequent event | Oppenheimer
Class of Stock [Line Items]
Amount of shares authorized to be sold (in shares)				15,000,000
Proceeds from the sale of common stock | $				$ 14,000
Number of warrants to purchase (in shares)				7,500,000
Warrant exercise price (in usd per share) | $ / shares				$ 1.1
Expiration term				5 years
Number of shares sold per each combination (in shares)				1
Number of warrants sold per each combination (in shares)				0.5
Number of securities called by each warrant or right (in shares)				1
Combined price of instruments issued per share (in dollars per share) | $ / shares				$ 1.00
Aspire Capital Fund,LLC
Class of Stock [Line Items]
Shares sold (in shares)										959,079