CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning balance (in shares) at Dec. 31, 2018				87,057	87,057
Beginning balance at Dec. 31, 2018	$ 228,250	$ 1,400	$ 229,650	$ 87	$ 87	$ 2,296,795	$ 2,296,795	$ (2,067,416)	$ 1,400	$ (2,066,016)	$ (1,216)	$ (1,216)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(5,924)							(5,924)
Other comprehensive income (loss), net of tax	(1,849)										(1,849)
Issuance of common stock under stock option, award and purchase plans (in shares)				4,014
Issuance of common stock under stock option, award and purchase plans	6,914			$ 4		6,910
Stock-based compensation	12,156					12,156
Issuance of warrant	16,142					16,142
Exercise of warrant (in shares)				804
Exercise of warrant	0			$ 1		(1)
Reclassification from equity to mezzanine equity for Notes	(2,410)					(2,410)
Portion of repurchase price recorded in additional paid-in capital in connection with partial repurchase of 2020 Notes	(27,111)					(27,111)
Conversion feature of Notes	24,878					24,878
Ending balance (in shares) at Dec. 31, 2019				91,875
Ending balance at Dec. 31, 2019	252,446			$ 92		2,327,359		(2,071,940)			(3,065)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(29,271)							(29,271)
Other comprehensive income (loss), net of tax	8,921										8,921
Issuance of common stock under stock option, award and purchase plans (in shares)				3,822
Issuance of common stock under stock option, award and purchase plans	3,810			$ 3		3,807
Stock-based compensation	18,034					18,034
Issuance of warrant	0
Exercise of warrant (in shares)				2,413
Exercise of warrant	0			$ 2		(2)
Reclassification from mezzanine equity to equity for 2020 Notes	2,410					2,410
Conversion feature of Notes	8,254					8,254
Conversion feature of exchanged portion of 2020 Notes	(6,909)					(6,909)
Issuance of common stock upon conversion of 2020 Notes (in shares)				94
Issuance of common stock upon conversion of 2020 Notes	607			$ 1		606
Ending balance (in shares) at Dec. 31, 2020				98,204
Ending balance at Dec. 31, 2020	258,302			$ 98		2,353,559		(2,101,211)			5,856
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	13,254							13,254
Other comprehensive income (loss), net of tax	(9,128)										(9,128)
Issuance of common stock under stock option, award and purchase plans (in shares)				4,755
Issuance of common stock under stock option, award and purchase plans	10,249			$ 5		10,244
Stock-based compensation	24,119					24,119
Issuance of warrant	0
Reclassification from equity to mezzanine equity for Notes	(883)					(883)
Ending balance (in shares) at Dec. 31, 2021				102,959
Ending balance at Dec. 31, 2021	$ 295,913			$ 103		$ 2,387,039		$ (2,087,957)			$ (3,272)