CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balances at beginning of period at Dec. 31, 2018	$ (166,661)	$ 423	$ 1,028,924	$ (1,187,010)	$ (5,231)	$ (3,767)
Balances at beginning of period (in shares) at Dec. 31, 2018		42,339			(391)
Stock issued pursuant to employee stock plans	(3,270)		(8,508)		$ 5,231
Stock issued pursuant to employee stock plans (in shares)		811			391
Stock-based compensation	7,958		7,958
Net (loss) income	7,601			7,601
Other comprehensive income (loss)	(163)					(163)
Partial retirement of convertible senior notes conversion feature	(577)		(577)
Partial unwind capped call cash receipt	27		27
Balances at end of period at Dec. 31, 2019	(155,085)	$ 430	1,027,824	(1,179,409)	$ 0	(3,930)
Balances at end of period (in shares) at Dec. 31, 2019		43,150			0
Stock issued pursuant to employee stock plans	$ (1,818)	$ 12	(1,830)		$ 0
Stock issued pursuant to employee stock plans (in shares)	1,270				0
Stock-based compensation	$ 10,664		10,664
Net (loss) income	11,062			11,062
Other comprehensive income (loss)	2,253					2,253
Balances at end of period at Dec. 31, 2020	$ (132,924)	$ 442	1,036,658	(1,168,347)	$ 0	(1,677)
Balances at end of period (in shares) at Dec. 31, 2020	41,948	44,420			0
Stock repurchased	$ (25,090)				$ (25,090)
Stock issued pursuant to employee stock plans	$ (18,749)	$ 13	(18,762)
Stock issued pursuant to employee stock plans (in shares)	1,408
Stock-based compensation	$ 13,737		13,737
Repurchase of common stock (in shares)					(874)
Net (loss) income	41,388
Other comprehensive income (loss)	(2,436)					(2,436)
Balances at end of period at Dec. 31, 2021	$ (124,074)	$ 455	$ 1,031,633	$ (1,126,959)	$ (25,090)	$ (4,113)
Balances at end of period (in shares) at Dec. 31, 2021	43,150	45,828			(874)