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, 2012	$ (385,592)	$ 423	$ 1,039,562	$ (1,357,679)	$ (75,542)	$ 7,644
Balances at beginning of period (in shares) at Dec. 31, 2012		42,339			(3,403)
Stock issued pursuant to employee stock plans	(96)		(3,095)		$ 2,999
Stock issued pursuant to employee stock plans (in shares)					146
Stock-based compensation	6,917		6,917
Purchase of capped call transactions	0
Repurchase of common stock	0
Comprehensive income:
Net income	21,153
Other comprehensive loss	(1,717)					(1,717)
Comprehensive income	19,436
Balances at end of period at Dec. 31, 2013	(359,335)	$ 423	1,043,384	(1,336,526)	$ (72,543)	5,927
Balances at end of period (in shares) at Dec. 31, 2013		42,339			(3,257)
Stock issued pursuant to employee stock plans	(436)		(4,928)		$ 4,492
Stock issued pursuant to employee stock plans (in shares)					212
Stock-based compensation	11,513		11,513
Purchase of capped call transactions	0
Repurchase of common stock	0
Comprehensive income:
Net income	14,728
Other comprehensive loss	(7,540)					(7,540)
Comprehensive income	7,188
Balances at end of period at Dec. 31, 2014	(341,070)	$ 423	1,049,969	(1,321,798)	$ (68,051)	(1,613)
Balances at end of period (in shares) at Dec. 31, 2014		42,339			(3,045)
Stock issued pursuant to employee stock plans	3,476		(14,215)		$ 17,691
Stock issued pursuant to employee stock plans (in shares)					823
Stock-based compensation	9,514		9,514
Convertible notes conversion feature (net of taxes of $6,493 and net of issuance cost of $1,088)	20,718		20,718
Purchase of capped call transactions	(10,125)		(10,125)
Repurchase of common stock	(7,999)		(23)		$ (7,976)
Repurchase of common stock (in shares)					(587)
Comprehensive income:
Net income	2,480
Other comprehensive loss	(6,566)					(6,566)
Comprehensive income	(4,086)
Balances at end of period at Dec. 31, 2015	$ (329,572)	$ 423	$ 1,055,838	$ (1,319,318)	$ (58,336)	$ (8,179)
Balances at end of period (in shares) at Dec. 31, 2015		42,339			(2,809)