Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2018	$ 0	$ 204,101	$ 1,223	$ (199,388)	$ 5,936
Balance (in shares) at Dec. 31, 2018	17,114
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(18,114)	(18,114)
Realized foreign currency translation gain from dissolution of subsidiary					0
Unrealized foreign currency translation adjustment	0	0	(9)	0	(9)
Stock-based compensation, net	$ 0	1,512	0	0	1,512
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	12,665	0	0	12,665
Issuance of common stock, net (in shares)	59,955
Conversion of preferred stock into common stock	$ 0	0	0	0	0
Conversion of preferred stock into common stock (in shares)	78,733
Balance at Dec. 31, 2019	$ 0	218,278	1,124	(217,502)	1,990
Balance (in shares) at Dec. 31, 2019	155,802
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(15,836)	(15,836)
Realized foreign currency translation gain from dissolution of subsidiary	0	0	(1,202)	0	(1,202)
Unrealized foreign currency translation adjustment	0	0	(19)	0	(19)
Stock-based compensation, net	$ 0	1,349	0	0	1,349
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	25,921	0	0	25,921
Issuance of common stock, net (in shares)	1,695,877
Exercise of warrants	$ 0	4,115	0	0	4,115
Exercise of warrants (in shares)	455,139
Conversion of preferred stock into common stock	$ 0	0	0	0	0
Conversion of preferred stock into common stock (in shares)	429,242
Balance at Dec. 31, 2020	$ 0	$ 249,663	$ (7)	$ (233,338)	$ 16,318
Balance (in shares) at Dec. 31, 2020	2,736,060