CONSOLIDATED STATEMENTS OF CHANGES IN CAPITAL DEFICIENCY - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Beginning balance		$ (52,881)	$ (29,457)	$ (9,957)
Share-based compensation related to stock options		835	498	337
Share-based compensation related to restricted stock award			16
Reclassification of embedded derivative				43,634
Convertible note conversions			1,369	18,654
Equity component of convertible notes				1,315
Convertible note payment			1,150
Net loss		(18,276)	(26,457)	(83,440)
Ending balance		(70,322)	(52,881)	(29,457)
Common Stock [Member]
Beginning balance	[1]	$ 15	$ 14	$ 12
Beginning balance (in shares)		14,838,213	14,372,880	12,413,409
Share-based compensation related to restricted stock award (in shares)			2,990
Convertible note conversions	[1]			$ 2
Convertible note conversions (in shares)			200,997	1,959,471
Convertible note payment	[1]		$ 1
Convertible note payment (in shares)			261,346
Ending balance	[1]	$ 15	$ 15	$ 14
Ending balance (in shares)		14,838,213	14,838,213	14,372,880
Additional Paid-in Capital [Member]
Beginning balance		$ 269,657	$ 266,625	$ 202,687
Share-based compensation related to stock options		835	498	337
Share-based compensation related to restricted stock award			16
Reclassification of embedded derivative				43,634
Convertible note conversions			1,369	18,652
Equity component of convertible notes				1,315
Convertible note payment			1,149
Ending balance		270,492	269,657	266,625
Accumulated Deficit [Member]
Beginning balance		(322,553)	(296,096)	(212,656)
Net loss		(18,276)	(26,457)	(83,440)
Ending balance		$ (340,829)	$ (322,553)	$ (296,096)

[1] Represents an amount less than $1.