Condensed Consolidated Statements of Stockholders' Deficit - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (shares) at Dec. 31, 2021		25	105,381
Beginning balance at Dec. 31, 2021	$ (24,854)	$ 0	$ 105	$ 770,619	$ (787,047)	$ (8,531)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(53,342)				(53,342)
Foreign currency translation adjustment	4,581					4,581
Adjustment relating to extinguishment of 2022 Notes	1,727			1,727
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan (shares)			2,465
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan, net of taxes withheld	196		$ 3	193
Share-based compensation	15,892			15,892
Series E preferred stock dividends	0			2,029	(2,029)
Ending balance (shares) at Sep. 30, 2022		25	107,846
Ending balance at Sep. 30, 2022	(55,800)	$ 0	$ 108	790,460	(842,418)	(3,950)
Beginning balance (shares) at Jun. 30, 2022		25	107,645
Beginning balance at Jun. 30, 2022	(43,690)	$ 0	$ 108	787,283	(825,984)	(5,097)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(15,743)				(15,743)
Foreign currency translation adjustment	1,147					1,147
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan (shares)			201
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan, net of taxes withheld	80			80
Share-based compensation	2,406			2,406
Series E preferred stock dividends	0			691	(691)
Ending balance (shares) at Sep. 30, 2022		25	107,846
Ending balance at Sep. 30, 2022	(55,800)	$ 0	$ 108	790,460	(842,418)	(3,950)
Beginning balance (shares) at Dec. 31, 2022		25	108,468
Beginning balance at Dec. 31, 2022	(70,118)	$ 0	$ 108	793,855	(857,752)	(6,329)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(31,846)				(31,846)
Foreign currency translation adjustment	(958)					(958)
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan (shares)			521
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan, net of taxes withheld	50			50
Issuance of shares (shares)			8,036
Issuance of common shares in connection with a public offering	6,057		$ 8	6,049
Share-based compensation	6,030			6,030
Series E preferred stock dividends	0			2,218	(2,218)
Ending balance (shares) at Sep. 30, 2023		25	117,025
Ending balance at Sep. 30, 2023	(90,783)	$ 0	$ 117	808,203	(891,815)	(7,288)
Beginning balance (shares) at Jun. 30, 2023		25	116,870
Beginning balance at Jun. 30, 2023	(70,815)	$ 0	$ 117	805,177	(869,254)	(6,855)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(21,805)				(21,805)
Foreign currency translation adjustment	(433)					(433)
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan (shares)			155
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan, net of taxes withheld	2			2
Share-based compensation	2,267			2,267
Series E preferred stock dividends	0			756	(756)
Ending balance (shares) at Sep. 30, 2023		25	117,025
Ending balance at Sep. 30, 2023	$ (90,783)	$ 0	$ 117	$ 808,203	$ (891,815)	$ (7,288)