WARRANTS (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Mar. 31, 2016	Jan. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Aug. 11, 2017	Aug. 10, 2017
Warrants to purchase common stock issued and outstanding
Number of Warrants			2,166,149
Weighted average exercise price			$ 9.93
Weighted average life in years			3 years 2 months 12 days
Proceeds from issuance of common stock and warrants				$ 29,905	$ 14,480
Common Stock
Warrants to purchase common stock issued and outstanding
Number of shares issued (in shares)					2,388,245
Warrants for purchase of common stock (in shares)			577,548		1,354,523	48,507
Common Stock | Public Offering, March 2016
Warrants to purchase common stock issued and outstanding
Warrants for purchase of common stock (in shares)	2,146,666
Equity issuance (in price per unit)	$ 7.49
Common Stock | Public offering
Warrants to purchase common stock issued and outstanding
Number of shares issued (in shares)		2,000,000
Common Stock | Derivative with Exercise Price Two
Warrants to purchase common stock issued and outstanding
Warrants for purchase of common stock (in shares)			13,429
Warrants
Fair value of warrants
Expected volatility (as a percent)			82.00%	89.00%	100.00%
Risk-free interest rate (as a percent)			1.91%	1.20%	0.65%
Expected term (in years)			1 year 4 months 6 days	2 years 4 months 24 days	3 years 4 months 24 days
Expected dividend yield (as a percent)			0.00%	0.00%	0.00%
Warrants | Public Offering, March 2016
Warrants to purchase common stock issued and outstanding
Warrant Exercise Price	10.00
Equity issuance (in price per unit)	$ 0.01
Percentage of warrant exercises price over public offering price	133.00%
Fair value of warrants
Fair value of warrants	$ 11,726
Expected volatility (as a percent)	112.82%
Risk-free interest rate (as a percent)	1.34%
Expected term (in years)	5 years
Expected dividend yield (as a percent)	0.00%
Warrants | Derivative with Exercise Price Two
Warrants to purchase common stock issued and outstanding
Warrant Exercise Price						$ 0.83	$ 3.87
Common Stock And Warrants | Public Offering, March 2016
Warrants to purchase common stock issued and outstanding
Number of shares issued (in shares)	4,293,333
Proceeds from issuance of common stock and warrants	$ 29,905
Equity | Derivative with Exercise Price One
Warrants to purchase common stock issued and outstanding
Warrants Issued Year			2012
Number of Warrants			6,054
Warrant Exercise Price			$ 6.64
Expiration date			Oct. 05, 2019
Equity | Derivative with Exercise Price Three
Warrants to purchase common stock issued and outstanding
Warrants Issued Year			2016
Number of Warrants			2,146,666
Warrant Exercise Price			$ 10.00
Expiration date			Mar. 18, 2021
Liability | Derivative with Exercise Price Two
Warrants to purchase common stock issued and outstanding
Warrants Issued Year			2014
Number of Warrants			13,429
Warrant Exercise Price			$ 0.83
Expiration date			May 09, 2019