Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Impact of adoption of Credit Loss Standard	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Deficit	Retained Deficit Impact of adoption of Credit Loss Standard
Beginning balance (in shares) at Dec. 31, 2019			1,464,544
Beginning balance, amount at Dec. 31, 2019	$ 407,343	$ (1,684)	$ 146	$ 1,970,047	$ (3,449)	$ (1,559,401)	$ (1,684)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation (in shares)			3,020
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation	1,730		$ 1	1,729
Contribution of services	91			91
Recognition of stock-based compensation of employee stock purchase plan	102			102
Common stock issued in connection with conversion of Loan Agreement with Thermo (in shares)			200,140
Common stock issued in connection with conversion of Loan Agreement with Thermo	120,461		$ 20	120,441
Other comprehensive income (loss)	5,303				5,303
Net loss	(38,223)					(38,223)
Ending balance (in shares) at Mar. 31, 2020			1,667,704
Ending balance, amount at Mar. 31, 2020	495,123		$ 167	2,092,410	1,854	(1,599,308)
Beginning balance (in shares) at Dec. 31, 2019			1,464,544
Beginning balance, amount at Dec. 31, 2019	407,343	$ (1,684)	$ 146	1,970,047	(3,449)	(1,559,401)	$ (1,684)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(62,959)
Ending balance (in shares) at Jun. 30, 2020			1,670,290
Ending balance, amount at Jun. 30, 2020	470,486		$ 167	2,093,877	486	(1,624,044)
Beginning balance (in shares) at Mar. 31, 2020			1,667,704
Beginning balance, amount at Mar. 31, 2020	495,123		$ 167	2,092,410	1,854	(1,599,308)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation (in shares)			1,354
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation	922			922
Contribution of services	47			47
Net issuance of stock through employee stock purchase plan and recognition of stock-based compensation (in shares)			1,188
Net issuance of stock through employee stock purchase plan and recognition of stock-based compensation	482			482
Common stock issued in connection with conversion of Loan Agreement with Thermo (in shares)			44
Common stock issued in connection with conversion of Loan Agreement with Thermo	16			16
Other comprehensive income (loss)	(1,368)				(1,368)
Net loss	(24,736)					(24,736)
Ending balance (in shares) at Jun. 30, 2020			1,670,290
Ending balance, amount at Jun. 30, 2020	470,486		$ 167	2,093,877	486	(1,624,044)
Beginning balance (in shares) at Dec. 31, 2020			1,674,669
Beginning balance, amount at Dec. 31, 2020	423,065		$ 167	2,096,566	(2,944)	(1,670,724)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation (in shares)			1,915
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation	1,875			1,875
Contribution of services	47			47
Recognition of stock-based compensation of employee stock purchase plan	79			79
Issuance of stock for employee stock option exercises (in shares)			83
Issuance of stock for employee stock option exercises	57			57
Issuance of stock for warrant exercises (in shares)			115,036
Issuance of stock for warrant exercises	43,678		$ 12	43,666
Other comprehensive income (loss)	3,242				3,242
Net loss	(36,333)					(36,333)
Ending balance (in shares) at Mar. 31, 2021			1,791,703
Ending balance, amount at Mar. 31, 2021	435,710		$ 179	2,142,290	298	(1,707,057)
Beginning balance (in shares) at Dec. 31, 2020			1,674,669
Beginning balance, amount at Dec. 31, 2020	423,065		$ 167	2,096,566	(2,944)	(1,670,724)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(57,782)
Ending balance (in shares) at Jun. 30, 2021			1,793,063
Ending balance, amount at Jun. 30, 2021	412,132		$ 179	2,143,319	(2,860)	(1,728,506)
Beginning balance (in shares) at Mar. 31, 2021			1,791,703
Beginning balance, amount at Mar. 31, 2021	435,710		$ 179	2,142,290	298	(1,707,057)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation (in shares)			173
Net issuance of restricted stock awards and stock for employee stock options and recognition of stock-based compensation	576			576
Contribution of services	47			47
Net issuance of stock through employee stock purchase plan and recognition of stock-based compensation (in shares)			1,187
Net issuance of stock through employee stock purchase plan and recognition of stock-based compensation	406			406
Other comprehensive income (loss)	(3,158)				(3,158)
Net loss	(21,449)					(21,449)
Ending balance (in shares) at Jun. 30, 2021			1,793,063
Ending balance, amount at Jun. 30, 2021	$ 412,132		$ 179	$ 2,143,319	$ (2,860)	$ (1,728,506)