Consolidated Statements of Stockholders' Deficit - USD ($) shares in Thousands, $ in Thousands	Total	At-the-market Offering	Convertible Notes Mann Group	2024 Convertible Notes	2024 Convertible Note Interest	Senior Convertible Notes Principal	Senior Convertible Notes Interest	Convertible Note Principal Mann Group	Convertible Note Interest Mann Group	Common Stock	Common Stock At-the-market Offering	Common Stock Convertible Notes Mann Group	Common Stock 2024 Convertible Notes	Common Stock 2024 Convertible Note Interest	Common Stock Senior Convertible Notes Principal	Common Stock Senior Convertible Notes Interest	Common Stock Convertible Note Principal Mann Group	Common Stock Convertible Note Interest Mann Group	Additional Paid-in Capital	Additional Paid-in Capital At-the-market Offering	Additional Paid-in Capital Convertible Notes Mann Group	Additional Paid-in Capital 2024 Convertible Notes	Additional Paid-in Capital 2024 Convertible Note Interest	Additional Paid-in Capital Senior Convertible Notes Principal	Additional Paid-in Capital Senior Convertible Notes Interest	Additional Paid-in Capital Convertible Note Principal Mann Group	Additional Paid-in Capital Convertible Note Interest Mann Group	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2019	$ (190,526)									$ 2,118									$ 2,799,278									$ (19)	$ (2,991,903)
Beginning Balance (in shares) at Dec. 31, 2019										211,788
Net issuance of common stock in association with stock options and restricted stock units	233									$ 6									227
Net issuance of common stock associated with stock options and restricted stock units (in shares)										653
Issuance of common stock pursuant to conversion notes						$ 5,261	$ 288	$ 7,000	$ 3,000						$ 26	$ 2	$ 28	$ 12						$ 5,235	$ 286	$ 6,972	$ 2,988
Issuance of common stock pursuant to conversion notes (in shares)															2,612	188	2,800	1,200
Issuance of common stock in at-the-market offering/placement		$ 23,530									$ 118									$ 23,412
Issuance of common stock in at-the-market offering/placement (in shares)											11,853
Issuance cost associated with at-the-market offering/placement	(519)																		(519)
Issuance of common stock under Employee Stock Purchase Plan	684									$ 6									678
Issuance of common stock under Employee Stock Purchase Plan (in shares)										627
Issuance of common stock from acquisition	9,250									$ 31									9,219
Issuance of common stock from acquisition (in shares)										3,067
Stock-based compensation expense	6,511																		6,511
Issuance of common stock from the exercise of warrants	11,600									$ 73									11,527
Issuance of common stock from the exercise of warrants (in Share)										7,250
Issuance of common stock from market price stock purchase	215									$ 1									214
Issuance of common stock under Market Price Stock Purchase Plan (in shares)										80
Issuance of warrants pursuant to Midcap Credit Facility	275																		275
Cumulative translation loss	19																											$ 19
Net loss	(57,240)																												(57,240)
Ending Balance at Dec. 31, 2020	(180,419)									$ 2,421									2,866,303										(3,049,143)
Ending Balance (in shares) at Dec. 31, 2020										242,118
Net issuance of common stock in association with stock options and restricted stock units	(498)									$ 16									(514)
Net issuance of common stock associated with stock options and restricted stock units (in shares)										1,572
Issuance of common stock pursuant to conversion notes			$ 9,573	$ 5,000					$ 427			$ 38	$ 17					$ 2			$ 9,535	$ 4,983					$ 425
Issuance of common stock pursuant to conversion notes (in shares)												3,830	1,667					170
Issuance of common stock pursuant to payoff of the 2024 convertible note interest					$ 143																		$ 143
Issuance of common stock pursuant to payoff of the 2024 convertible note interest (in shares)														27
Issuance of common stock in at-the-market offering/placement		$ 1,886									$ 6									$ 1,880
Issuance of common stock in at-the-market offering/placement (in shares)											578
Issuance cost associated with at-the-market offering/placement	(38)																		(38)
Issuance of common stock under Employee Stock Purchase Plan	1,090									$ 5									1,085
Issuance of common stock under Employee Stock Purchase Plan (in shares)										527
Stock-based compensation expense	12,200																		12,200
Premium on Mann Group convertible note	22,107																		22,107
Issuance of common stock from market price stock purchase	106																		106
Issuance of common stock under Market Price Stock Purchase Plan (in shares)										25
Issuance of common stock pursuant to a warrant conversion										$ 10									(10)
Issuance of common stock pursuant to a warrant conversion (shares)										964
Net loss	(80,926)																												(80,926)
Ending Balance at Dec. 31, 2021	$ (209,349)									$ 2,515									$ 2,918,205										$ (3,130,069)
Ending Balance (in shares) at Dec. 31, 2021										251,478