Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings (Accumulated Deficit) [Member]
BALANCE at Dec. 31, 2012	$ 611,790	$ 816	$ (213,988)	$ 596,826	$ (4,785)	$ 232,921
BALANCE, shares at Dec. 31, 2012			(14,547,000)
BALANCE, shares at Dec. 31, 2012		81,617,000
Net income (loss)	(164,263)					(164,263)
Foreign currency translation gain	4,295				4,295
Unrealized loss on investments	(13)				(13)
COMPREHENSIVE INCOME (LOSS)	(159,981)
Share-based compensation expense:
Stock option plan	2,308			2,308
Restricted stock award plan	4,339			4,339
Employee stock purchase plan	52			52
Common stock issued under:
Stock option plan	$ 4			4
Stock option plan, shares	1,275	1,000
Restricted stock award plan	$ (506)	$ (1)	$ (506)	1
Restricted stock award plan, shares		(131,000)	(172,000)
Employee stock purchase plan	$ 994	$ 4		990
Employee stock purchase plan, shares	400,000	403,000
Tax effect of options exercised and stock settlements	$ (3,616)			(3,616)
BALANCE at Dec. 31, 2013	455,384	$ 819	$ (214,494)	600,904	(503)	68,658
BALANCE, shares at Dec. 31, 2013			(14,719,000)
BALANCE, shares at Dec. 31, 2013		81,890,000
Net income (loss)	(178,163)					(178,163)
Unrealized loss on investments	(350)				(350)
COMPREHENSIVE INCOME (LOSS)	(178,513)
Share-based compensation expense:
Stock option plan	1,372			1,372
Restricted stock award plan	2,865			2,865
Employee stock purchase plan	40			40
Common stock issued under:
Stock option plan	$ 612	$ 2		610
Stock option plan, shares	225,000	225,000	0
Restricted stock award plan	$ (671)	$ 1	$ (671)	(1)
Restricted stock award plan, shares		95,000	(97,000)
Employee stock purchase plan	$ 742	$ 1		741
Employee stock purchase plan, shares	100,000	127,000
BALANCE at Dec. 31, 2014	$ 281,933	$ 823	$ (215,165)	606,531	(853)	(109,403)
BALANCE, shares at Dec. 31, 2014	(14,815,651)		(14,816,000)
BALANCE, shares at Dec. 31, 2014	82,336,689	82,337,000
Common stock issued under:
Cumulative adjustment for change from cost method investment to equity method investment	$ 102					102
Net income (loss)	51,885					51,885
Unrealized loss on investments	(27)				(27)
COMPREHENSIVE INCOME (LOSS)	51,858
Stock option plan	442			442
Restricted stock award plan	2,385			2,385
Employee stock purchase plan	30			30
Stock option plan	$ 828	$ 3		825
Stock option plan, shares	303,035	303,000
Restricted stock award plan	$ (439)	$ 2	$ (441)
Restricted stock award plan, shares		214,000	(82,000)
Employee stock purchase plan	$ 573	$ 2		571
Employee stock purchase plan, shares	100,000	143,000
BALANCE at Dec. 31, 2015	$ 337,610	$ 830	$ (215,606)	$ 610,784	$ (880)	$ (57,518)
BALANCE, shares at Dec. 31, 2015	(14,897,931)		(14,898,000)
BALANCE, shares at Dec. 31, 2015	82,996,585	82,997,000