Condensed Consolidated Statements of Stockholders' Deficit - USD ($) shares in Thousands, $ in Thousands	Total	Convertible Note Interest The Mann Group L L C	At-the-market Placement	Common Stock	Common Stock Convertible Note Interest The Mann Group L L C	Common Stock At-the-market Placement	Additional Paid-in Capital	Additional Paid-in Capital Convertible Note Interest The Mann Group L L C	Additional Paid-in Capital At-the-market Placement	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ (209,349)			$ 2,515			$ 2,918,205				$ (3,130,069)
Beginning Balance (in shares) at Dec. 31, 2021				251,478
Net issuance of common stock associated with stock options and restricted stock units	129			$ 4			125
Net issuance of common stock associated with stock options and restricted stock units (in shares)				450
Issuance of common stock under the employee stock purchase plan	740			$ 2			738
Issuance of common stock under the employee stock purchase plan (in shares)				233
Stock-based compensation expense	2,806						2,806
Issuance of common stock from market price stock purchase plan	684			$ 3			681
Issuance of common stock from Market Price Stock Purchase Plan (in shares)				252
Cumulative loss on available-for-sale securities	(1,076)									$ (1,076)
Net loss	(25,998)										(25,998)
Ending Balance at Mar. 31, 2022	(232,064)			$ 2,524			2,922,555			$ (1,076)	(3,156,067)
Ending Balance (in shares) at Mar. 31, 2022				252,413
Beginning Balance at Dec. 31, 2022	(250,538)			$ 2,638			2,964,293				(3,217,469)
Beginning Balance (in shares) at Dec. 31, 2022				263,793
Net issuance of common stock associated with stock options and restricted stock units	52			$ 2			50
Net issuance of common stock associated with stock options and restricted stock units (in shares)				206
Stock-based compensation expense	3,655						3,655
Issuance of common stock pursuant to conversion notes		$ 55						$ 55
Issuance of common stock pursuant to conversion notes (in shares)					11
Issuance of at-the-market placement			$ 1,199			$ 3			$ 1,196
Issuance of at-the-market placement (in shares)						269
Issuance costs associated with at-the- market placement	(24)						(24)
Net loss	(9,795)										(9,795)
Ending Balance at Mar. 31, 2023	$ (255,396)			$ 2,643			$ 2,969,225				$ (3,227,264)
Ending Balance (in shares) at Mar. 31, 2023				264,279