Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Noncontrolling Interest [Member]	Common Stock [Member]	Additional-paid-in capital [Member]	Accumulated deficit [Member]	Accumulated other comprehensive income (loss) [Member]
Beginning Balance at Dec. 31, 2012	$ 415,450		$ 4	$ 1,392,098	$ (976,376)	$ (276)
Beginning balance, shares at Dec. 31, 2012			40,832
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for stock options and restricted stock units	2,841			2,841
Common stock issued for stock options and restricted stock units, Shares			584
Common stock issued for employee stock purchase plan	1,065			1,065
Common stock issued for employee stock purchase plan, Shares			85
Common stock issued upon Warrant exercise	9,620			9,620
Common stock issued upon Warrant exercise, Shares			1,000
Stock repurchases	(10,006)			(10,006)
Stock repurchases, Shares			(418)
Convertible senior notes, net of issuance costs of $714 and tax effect of $7,785	13,842			13,842
Settlement of derivative instrument (Warrant)	20,217			20,217
Other comprehensive income (loss)	276					276
Stock-based compensation	11,642			11,642
Tax effect of equity compensation	27,224			27,224
Taxes paid on stock issued for equity awards	(2,500)			(2,500)
Net income (loss)	24,399				24,399
Ending balance, shares at Dec. 31, 2013			42,083
Ending Balance at Dec. 31, 2013	514,070		$ 4	1,466,043	(951,977)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for stock options and restricted stock units	6,715			6,715
Common stock issued for stock options and restricted stock units, Shares			1,003
Common stock issued for employee stock purchase plan	1,376			1,376
Common stock issued for employee stock purchase plan, Shares			85
Stock repurchases	(38,650)			(38,650)
Stock repurchases, Shares			(2,289)
Other comprehensive income (loss)	(1,113)					(1,113)
Stock-based compensation	11,990			11,990
Tax effect of equity compensation	22,962			22,962
Taxes paid on stock issued for equity awards	(2,778)			(2,778)
Net income (loss)	$ (35,547)				(35,547)
Ending balance, shares at Dec. 31, 2014	40,882		40,882
Ending Balance at Dec. 31, 2014	$ 479,025		$ 4	1,467,658	(987,524)	(1,113)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for stock options and restricted stock units	2,409			2,409
Common stock issued for stock options and restricted stock units, Shares			520
Common stock issued for employee stock purchase plan	1,193			1,193
Common stock issued for employee stock purchase plan, Shares			103
Stock repurchases	(7,735)			(7,735)
Stock repurchases, Shares			(551)
Other comprehensive income (loss)	586					586
Stock-based compensation	13,047			13,047
Tax effect of equity compensation	15,378			15,378
Taxes paid on stock issued for equity awards	(1,545)			(1,545)
Net income (loss)	$ (40,074)				(40,074)
Purchase of redeemable non-controlling interests		$ 15,038
Ending balance, shares at Dec. 31, 2015	40,954		40,954
Ending Balance at Dec. 31, 2015	$ 462,284	$ 15,038	$ 4	$ 1,490,405	$ (1,027,598)	$ (527)