Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands	Total	Public Offering	At-the-market Offering	At-The-Market-Placement	Note Payable to Related Party	Senior Convertible Notes	Facility Financing Obligation	Promissory notes Mann Group	Common Stock	Common Stock Public Offering	Common Stock At-the-market Offering	Common Stock At-The-Market-Placement	Common Stock Note Payable to Related Party	Common Stock Senior Convertible Notes	Common Stock Facility Financing Obligation	Common Stock Promissory notes Mann Group	Additional Paid-in Capital	Additional Paid-in Capital Public Offering	Additional Paid-in Capital At-the-market Offering	Additional Paid-in Capital At-The-Market-Placement	Additional Paid-in Capital Note Payable to Related Party	Additional Paid-in Capital Senior Convertible Notes	Additional Paid-in Capital Facility Financing Obligation	Additional Paid-in Capital Promissory notes Mann Group	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2017	$ (214,732)								$ 1,192								$ 2,638,992								$ (18)	$ (2,854,898)
Beginning Balance (in shares) at Dec. 31, 2017									119,053,000
Exercise of stock options	7																7
Exercise of stock options (in shares)									7,000
Issuance of common stock from the release of restricted stock units	1								$ 2								(1)
Issuance of common stock from the release of restricted stock units (in shares)									193,000
Issuance of common stock under Employee Stock Purchase Plan	345								$ 3								342
Issuance of common stock under Employee Stock Purchase Plan (in shares)									400,000
Stock-based compensation expense	6,857																6,857
Issuance of common stock pursuant to conversion notes					$ 8,160	$ 4,980	$ 38,128						$ 30	$ 27	$ 197						$ 8,130	$ 4,953	$ 37,931
Issuance of common stock pursuant to conversion notes (in shares)													3,000,000	2,726,000	19,726,000
Issuance of common stock — direct placement	28,000								$ 140								27,860
Issuance of common stock — direct placement									14,000,000
Issuance costs associated with direct placement	(1,610)																(1,610)
Issuance of common stock		$ 40,000		$ 2,089						$ 267		$ 10						$ 39,733		$ 2,079
Issuance of common stock (in shares)										26,667,000		1,028,000
Issuance cost associated with public offering	(2,538)																(2,538)
Issuance costs associated with at-the-market placement	(84)																(84)
Issuance of common stock under Market Price Stock Purchase Plan	430								$ 2								428
Issuance of common stock under Market Price Stock Purchase Plan (in shares)									230,000
Amortization of shelf fees	(12)																(12)
Cumulative translation (loss) gain	(1)																								(1)
Adjustment to adopt ASU 2014-09 (Topic 606) | Topic 606	1,873																									1,873
Net loss	(86,975)																									(86,975)
Ending Balance at Dec. 31, 2018	(175,082)								$ 1,870								2,763,067								(19)	(2,940,000)
Ending Balance (in shares) at Dec. 31, 2018									187,030,000
Exercise of stock options	$ 124								$ 1								123
Exercise of stock options (in shares)	67,461								68,000
Issuance of common stock from the release of restricted stock units	$ (2)								$ 7								(9)
Issuance of common stock from the release of restricted stock units (in shares)									705,000
Issuance of common stock under Employee Stock Purchase Plan	656								$ 7								649
Issuance of common stock under Employee Stock Purchase Plan (in shares)									653,000
Stock-based compensation expense	6,203																6,203
Issuance of common stock pursuant to conversion notes	4,575					$ 5,575		$ 8,000	$ 42					$ 49		$ 71	4,533					$ 5,526		$ 7,929
Issuance of common stock pursuant to conversion notes (in shares)									4,193,000					4,911,000		7,143,000
Issuance of common stock			$ 3,199								$ 26								$ 3,173
Issuance of common stock (in shares)											2,585,000
Issuance costs associated with at-the-market placement	(60)																(60)
Issuance of warrants pursuant to MidCap Credit Facility	1,854																1,854
Issuance of common stock from the exercise of warrants	5,900								$ 45								5,855
Issuance of common stock from the exercise of warrants (in Share)									4,500,000
Warrant modification	688																688
Repurchase of warrants	(253)																(253)
Net loss	(51,903)																									(51,903)
Ending Balance at Dec. 31, 2019	$ (190,526)								$ 2,118								$ 2,799,278								$ (19)	$ (2,991,903)
Ending Balance (in shares) at Dec. 31, 2019									211,788,000