CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands		Total		Common Stock		Additional Paid-in Capital		Treasury Stock		Company Stock Held By NQDC		Accumulated other comprehensive income (loss)		Accumulated Deficit		Accumulated Deficit Impact of change in accounting principles
Beginning balance (in shares) at Dec. 31, 2018	[1]			178,253
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under equity incentive plans (in shares)				1,180
Repurchase of common stock (in shares)				0
Ending balance (in shares) at Jun. 30, 2019				179,433
Beginning Balance at Dec. 31, 2018		$ 2,967,940	[1]	$ 178	[1]	$ 4,669,926	[1]	$ 0	[1]	$ (13,301)	[1]	$ 5,271	[1]	$ (1,694,134)	[1]	$ (2,727)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock						0		0
Retirement of treasury stock								0
Issuances under equity incentive plans, net of tax				1		(17,889)
Stock-based compensation						82,068
Common stock held by the NQDC						(442)				442
Accounting impact of NQDC Plan Change						10,653				2,648
Other comprehensive income (loss)												12,168
Net income (loss)		(93,908)												(93,908)
Ending Balance at Jun. 30, 2019		2,960,954		$ 179		4,744,316		0		(10,211)		17,439		(1,790,769)
Beginning balance (in shares) at Mar. 31, 2019	[1]			179,033
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under equity incentive plans (in shares)				400
Repurchase of common stock (in shares)				0
Ending balance (in shares) at Jun. 30, 2019				179,433
Beginning Balance at Mar. 31, 2019		2,936,627	[1]	$ 179	[1]	4,682,900	[1]	0	[1]	(12,912)	[1]	19,794	[1]	(1,753,334)	[1]	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock						0		0
Retirement of treasury stock								0
Issuances under equity incentive plans, net of tax				0		10,843
Stock-based compensation						40,362
Common stock held by the NQDC						(442)				53
Accounting impact of NQDC Plan Change						10,653				2,648
Other comprehensive income (loss)												(2,355)
Net income (loss)		(37,435)												(37,435)
Ending Balance at Jun. 30, 2019		2,960,954		$ 179		4,744,316		0		(10,211)		17,439		(1,790,769)
Beginning balance (in shares) at Dec. 31, 2019	[1]			179,838
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under equity incentive plans (in shares)				1,828
Repurchase of common stock (in shares)				(518)
Ending balance (in shares) at Jun. 30, 2020				181,148
Beginning Balance at Dec. 31, 2019		3,122,381	[1],[2]	$ 180	[1]	4,832,707	[1]	0	[1]	(9,961)	[1]	20,164	[1]	(1,720,709)	[1]	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock						(50,000)		(50,000)
Retirement of treasury stock								50,000
Issuances under equity incentive plans, net of tax				1		10,282
Stock-based compensation						91,931
Common stock held by the NQDC						717				(717)
Accounting impact of NQDC Plan Change						0				0
Other comprehensive income (loss)												9,886
Net income (loss)		52,198												52,198
Ending Balance at Jun. 30, 2020		3,236,679		$ 181		4,885,637		0		(10,678)		30,050		(1,668,511)
Beginning balance (in shares) at Mar. 31, 2020	[1]			180,762
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances under equity incentive plans (in shares)				904
Repurchase of common stock (in shares)				(518)
Ending balance (in shares) at Jun. 30, 2020				181,148
Beginning Balance at Mar. 31, 2020		3,239,962	[1]	$ 181	[1]	4,854,814	[1]	0	[1]	(9,832)	[1]	34,127	[1]	(1,639,328)	[1]	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock						(50,000)		(50,000)
Retirement of treasury stock								50,000
Issuances under equity incentive plans, net of tax				0		34,509
Stock-based compensation						45,468
Common stock held by the NQDC						846				(846)
Accounting impact of NQDC Plan Change						0				0
Other comprehensive income (loss)												(4,077)
Net income (loss)		(29,183)												(29,183)
Ending Balance at Jun. 30, 2020		$ 3,236,679		$ 181		$ 4,885,637		$ 0		$ (10,678)		$ 30,050		$ (1,668,511)

[1] The beginning balances for the six-month periods were derived from the audited Consolidated Financial Statements included in Company’s Annual Report on Form 10-K for the years ended December 31, 2019 and 2018, respectively, filed with the SEC on February 27, 2020.

[2] December 31, 2019 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the SEC on February 27, 2020.