Consolidated Statements Of Redeemable Preferred Stock and Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Series E Convertible Preferred Stock	Series F Convertible Preferred Stock	July 2020 Warrants	June 2020 Warrants	Common Stock	Common Stock Series E Convertible Preferred Stock	Common Stock Series F Convertible Preferred Stock	Common Stock June 2020 Warrants	Additional Paid-in Capital	Additional Paid-in Capital Series E Convertible Preferred Stock	Additional Paid-in Capital Series F Convertible Preferred Stock	Additional Paid-in Capital July 2020 Warrants	Additional Paid-in Capital June 2020 Warrants	Convertible Preferred Stock	Convertible Preferred Stock Series F Convertible Preferred Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit	Mezzanine Equity Series E Convertible Preferred Stock
Beginning balance at Dec. 31, 2019	$ 377					$ 31				$ 235,594							$ (701)	$ (234,547)
Beginning balance at Dec. 31, 2019																			$ 3,965
Beginning balance, shares at Dec. 31, 2019																			70,000
Balance (in shares) at Dec. 31, 2019						31,459,000
Issuance of convertible preferred stock in rights offering, net of offering costs			$ 2,411													$ 2,411
Issuance of convertible preferred stock in rights offering, net of offering costs, shares																18,000
Beneficial conversion on Convertible Preferred Stock												$ 2,700				$ (2,700)
Conversion of convertible preferred stock		$ 3,965					$ 7	$ 43			$ 3,958	16,905				$ (16,948)			$ (3,965)
Conversion of convertible preferred stock, shares							6,957,000	42,370,000								(17,000)			(70,000)
Sale of common stock	3,872					$ 11				3,861
Sale of common stock, shares						10,800,000
Sale of common stock warrants	3,031			$ 9,450						3,031			$ 9,450
Issuance of restricted shares	164
Deemed Dividend on Convertible Preferred Stock	(17,378)											(17,378)				$ 17,378
Stock offering costs	(856)									(856)
Stock-based compensation	1,846									1,846
Warrants issued in connection with debt instruments	67									67
Issuance of stock from RSUs, net	162					$ 1				161
Issuance of stock from RSUs, net, shares						1,297,000
Exercise of common stock warrants					$ 46									$ 46
Exercise of common stock warrants, shares									116,000
Net loss	(10,687)																	(10,687)
Foreign currency translation adjustments	167																167
Ending balance at Sep. 30, 2020	13,851					$ 93				259,385					$ 141		(534)	(245,234)
Balance (in shares) at Sep. 30, 2020						92,999,000
Ending balance, shares at Sep. 30, 2020															1,000
Beginning balance at Dec. 31, 2019	377					$ 31				235,594							(701)	(234,547)
Beginning balance at Dec. 31, 2019																			$ 3,965
Beginning balance, shares at Dec. 31, 2019																			70,000
Balance (in shares) at Dec. 31, 2019						31,459,000
Sale of common stock, shares			17,000
Ending balance at Dec. 31, 2020	$ 10,028					$ 98				261,573						$ 118	(385)	(251,376)
Balance (in shares) at Dec. 31, 2020	97,709,000					97,709,000
Ending balance, shares at Dec. 31, 2020	0		882													1,000
Beginning balance at Jun. 30, 2020	$ 1,308					$ 50				247,149							(645)	(245,246)
Balance (in shares) at Jun. 30, 2020						50,322,000
Issuance of convertible preferred stock in rights offering, net of offering costs			$ 2,411													$ 2,411
Issuance of convertible preferred stock in rights offering, net of offering costs, shares																18,000
Beneficial conversion on Convertible Preferred Stock												2,700				$ (2,700)
Conversion of convertible preferred stock								$ 43				16,905				$ (16,948)
Conversion of convertible preferred stock, shares								42,370,000								(17,000)
Sale of common stock warrants				$ 9,450									$ 9,450
Deemed Dividend on Convertible Preferred Stock	(17,378)											$ (17,378)				$ 17,378
Stock-based compensation	513									513
Issuance of stock from RSUs, net, shares						191,000
Exercise of common stock warrants					$ 46									$ 46
Exercise of common stock warrants, shares									116,000
Net loss	12																	12
Foreign currency translation adjustments	111																111
Ending balance at Sep. 30, 2020	13,851					$ 93				259,385					$ 141		(534)	(245,234)
Balance (in shares) at Sep. 30, 2020						92,999,000
Ending balance, shares at Sep. 30, 2020															1,000
Beginning balance at Dec. 31, 2020	$ 10,028					$ 98				261,573						$ 118	(385)	(251,376)
Beginning balance, shares at Dec. 31, 2020	0		882													1,000
Balance (in shares) at Dec. 31, 2020	97,709,000					97,709,000
Conversion of convertible preferred stock						$ 2				628						$ (630)
Conversion of convertible preferred stock, shares						1,577,000										(1,000)
Sale of common stock	$ 13,291					$ 14				13,277
Sale of common stock, shares			18,000			14,000,000
Exercise of stock option Shares	176,000					176,000
Exercise of stock option	$ 66									66
Issuance of restricted shares, Shares						260,000
Issuance of restricted shares										164
Issuance of common stock for settlement of liability	510					$ 1				509
Issuance of common stock for settlement of liability, Shares						500,000
Deemed Dividend on Convertible Preferred Stock	(546)									(546)						$ 546
Stock-based compensation	2,253									2,253
Issuance of stock from RSUs, net						$ 3				(3)
Issuance of stock from RSUs, net, shares						3,381,000
Exercise of common stock warrants	15,062					$ 35				15,027
Exercise of common stock warrants, shares						35,719,000
Net loss	(10,879)																	(10,879)
Foreign currency translation adjustments	(173)																(173)
Ending balance at Sep. 30, 2021	$ 30,322					$ 153				292,948						34	(558)	(262,255)
Balance (in shares) at Sep. 30, 2021	153,322,000					153,322,000
Ending balance, shares at Sep. 30, 2021	0		251
Beginning balance at Jun. 30, 2021	$ 33,256					$ 151				292,517						35	(468)	(258,979)
Balance (in shares) at Jun. 30, 2021						151,236,000
Conversion of convertible preferred stock										10						(10)
Conversion of convertible preferred stock, shares						25,000
Exercise of stock option Shares						176,000
Exercise of stock option	$ 66									66
Issuance of restricted shares, Shares	260,000
Issuance of restricted shares	$ 164									164
Deemed Dividend on Convertible Preferred Stock	(9)									(9)						9
Stock-based compensation	192									192
Issuance of stock from RSUs, net						$ 2				(2)
Issuance of stock from RSUs, net, shares						1,600,000
Exercise of common stock warrants	10									10
Exercise of common stock warrants, shares						25,000
Net loss	(3,276)																	(3,276)
Foreign currency translation adjustments	(90)																(90)
Ending balance at Sep. 30, 2021	$ 30,322					$ 153				$ 292,948						$ 34	$ (558)	$ (262,255)
Balance (in shares) at Sep. 30, 2021	153,322,000					153,322,000
Ending balance, shares at Sep. 30, 2021	0		251