Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid in Capital	Accumulated deficit	Accumulated other comprehensive income (loss)	Non-controlling interest	Total
Balance at Dec. 31, 2016	$ 5	$ 342,547	$ (338,224)	$ (31)	$ 830	$ 5,127
Balance (in shares) at Dec. 31, 2016	450,660
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss			(24,092)			(24,092)
Other comprehensive income (loss)				34		34
Stock-based compensation		1,710				1,710
Issuance of common stock, net	$ 3	6,357				6,360
Issuance of common stock, net (in shares)	267,418
Balance at Dec. 31, 2017	$ 8	350,614	(362,316)	3	830	$ (10,861)
Balance (in shares) at Dec. 31, 2017	718,078					718,078
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss			(20,573)		163	$ (20,410)
Other comprehensive income (loss)				(15)		(15)
Stock-based compensation		1,147				1,147
Dissolution of GBO			993		$ (993)
Shares issued in connection with reverse stock split (in shares)	101
Issuance of common stock and pre-funded warrants, net	$ 42	34,895				34,937
Issuance of common stock and pre-funded warrants, net (in shares)	4,215,581
Issuance of common stock upon exercise of warrants	$ 7	582				589
Issuance of common stock upon exercise of warrants (in shares)	740,460
Balance at Dec. 31, 2018	$ 57	$ 387,238	$ (381,896)	$ (12)		$ 5,387
Balance (in shares) at Dec. 31, 2018	5,674,220					5,674,220