CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Preferred Stock Related Party	Common stock	Common stock Related Party	Contributed capital	Contributed capital Related Party	Contributed capital Cumulative effect of accounting changes	Accumulated deficit	Accumulated deficit Cumulative effect of accounting changes	Treasury stock	Accumulated other comprehensive (loss) income
Beginning balance (in shares) at Dec. 31, 2021		3,955,000
Beginning balance (in shares) at Dec. 31, 2021				6,767,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards released (in shares)				112,000
Issuance of common stock under employee purchase plan (in shares)				13,000
Issuance of shares to retire convertible notes (in shares)				1,080,000
Ending balance (in shares) at Jun. 30, 2022		3,955,000
Ending balance (in shares) at Jun. 30, 2022				7,972,000
Beginning balance, amount at Dec. 31, 2021		$ 4		$ 7		$ 580,714		$ (37,438)	$ (570,668)	$ 25,922	$ (45,067)	$ (60)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options						6
Issuance of common stock under employee purchase plan						137
Issuance of shares to retire convertible notes				1		10,169
Equity-based compensation						6,659
Reclassification of common stock par value due to reverse stock split						11
Net loss	$ (31,988)								(31,988)
Net unrealized gain (loss) on debt securities available-for-sale	(132)											(132)
Foreign currency translation adjustment	(240)											(240)
Ending balance, amount at Jun. 30, 2022	(61,963)	$ 4		$ 8		560,258			(576,734)		(45,067)	(432)
Beginning balance (in shares) at Mar. 31, 2022		3,955,000
Beginning balance (in shares) at Mar. 31, 2022				6,873,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards released (in shares)				97,000
Issuance of common stock under employee purchase plan (in shares)				7,000
Issuance of shares to retire convertible notes (in shares)				995,000
Ending balance (in shares) at Jun. 30, 2022		3,955,000
Ending balance (in shares) at Jun. 30, 2022				7,972,000
Beginning balance, amount at Mar. 31, 2022		$ 4		$ 7		547,444			(558,211)		(45,067)	(232)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options						6
Issuance of common stock under employee purchase plan						60
Issuance of shares to retire convertible notes				1		8,912
Equity-based compensation						3,826
Reclassification of common stock par value due to reverse stock split						10
Net loss	(18,523)								(18,523)
Net unrealized gain (loss) on debt securities available-for-sale	(39)											(39)
Foreign currency translation adjustment	(161)											(161)
Ending balance, amount at Jun. 30, 2022	$ (61,963)	$ 4		$ 8		560,258			(576,734)		(45,067)	(432)
Beginning balance (in shares) at Dec. 31, 2022	3,954,546	3,955,000
Beginning balance (in shares) at Dec. 31, 2022	9,747,755			9,749,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock into common stock with related party (in shares)			(3,955,000)		396,000
Issuance of stock (in shares)					488,000
Restricted stock awards released (in shares)				293,000
Issuance of shares to retire senior promissory notes with related party (in shares)					3,432,000
Ending balance (in shares) at Jun. 30, 2023	0	0
Ending balance (in shares) at Jun. 30, 2023	14,357,953			14,358,000
Beginning balance, amount at Dec. 31, 2022	$ (22,264)	$ 4		$ 10		630,428			(607,239)		(45,067)	(400)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock into common stock with related party			$ (4)
Issuance of common stock to a related party					$ 1	3,996
Capital contribution from modification of securities purchase agreement with related party							$ 1,805
Issuance of shares to retire senior promissory notes with related party					$ 3		25,363
Equity-based compensation						2,177
Reclassification of common stock par value due to reverse stock split						43
Net loss	(49,530)								(49,530)
Net unrealized gain (loss) on debt securities available-for-sale	28											27
Foreign currency translation adjustment	(281)											(280)
Ending balance, amount at Jun. 30, 2023	$ (38,663)	$ 0		$ 14		663,812			(656,769)		(45,067)	(653)
Beginning balance (in shares) at Mar. 31, 2023		3,955,000
Beginning balance (in shares) at Mar. 31, 2023				9,964,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock into common stock with related party (in shares)			(3,955,000)		396,000
Issuance of stock (in shares)					488,000
Restricted stock awards released (in shares)				78,000
Issuance of shares to retire senior promissory notes with related party (in shares)					3,432,000
Ending balance (in shares) at Jun. 30, 2023	0	0
Ending balance (in shares) at Jun. 30, 2023	14,357,953			14,358,000
Beginning balance, amount at Mar. 31, 2023		$ 4		$ 10		630,992			(624,034)		(45,067)	(631)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock into common stock with related party			$ (4)
Issuance of common stock to a related party					$ 1	3,996
Capital contribution from modification of securities purchase agreement with related party							1,805
Issuance of shares to retire senior promissory notes with related party					$ 3		$ 25,363
Equity-based compensation						1,615
Reclassification of common stock par value due to reverse stock split						41
Net loss	$ (32,735)								(32,735)
Net unrealized gain (loss) on debt securities available-for-sale	4											3
Foreign currency translation adjustment	(26)											(25)
Ending balance, amount at Jun. 30, 2023	$ (38,663)	$ 0		$ 14		$ 663,812			$ (656,769)		$ (45,067)	$ (653)