CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Total
Balances at Dec. 31, 2018	$ 213	$ 3,813,678	$ (10,165)	$ (1,877,759)	$ 1,925,967
Increase (Decrease) in Stockholders' Equity
Issuance of shares of Common Stock upon exercise of stock options and settlement of employee restricted stock units	1	15,480			15,481
Issuance of shares of Common Stock for services rendered		104			104
Stock compensation		40,690			40,690
Other comprehensive income			918		918
Net income (loss)				102,312	102,312
Balances at Mar. 31, 2019	214	3,869,952	(9,247)	(1,775,352)	2,085,567
Balances at Dec. 31, 2018	213	3,813,678	(10,165)	(1,877,759)	1,925,967
Increase (Decrease) in Stockholders' Equity
Other comprehensive income					1,200
Net income (loss)					207,630
Balances at Jun. 30, 2019	215	3,925,975	(8,965)	(1,670,034)	2,247,191
Increase (Decrease) in Stockholders' Equity
Adoption of ASU				95	95
Balances at Mar. 31, 2019	214	3,869,952	(9,247)	(1,775,352)	2,085,567
Increase (Decrease) in Stockholders' Equity
Issuance of shares of Common Stock upon exercise of stock options and settlement of employee restricted stock units and shares of Common Stock under the ESPP	1	15,190			15,191
Issuance of shares of Common Stock for services rendered		123			123
Stock compensation		40,710			40,710
Other comprehensive income			282		282
Net income (loss)				105,318	105,318
Balances at Jun. 30, 2019	215	3,925,975	(8,965)	(1,670,034)	2,247,191
Balances at Dec. 31, 2019	216	4,044,490	(15,542)	(1,430,758)	2,598,406
Increase (Decrease) in Stockholders' Equity
Issuance of shares of Common Stock upon exercise of stock options and settlement of employee restricted stock units	1	14,618			14,619
Issuance of shares of Common Stock for services rendered		145			145
Stock compensation		42,758			42,758
Other comprehensive income			2,435		2,435
Net income (loss)				(720,642)	(720,642)
Balances at Mar. 31, 2020	217	4,102,011	(13,107)	(2,151,400)	1,937,721
Balances at Dec. 31, 2019	216	4,044,490	(15,542)	(1,430,758)	2,598,406
Increase (Decrease) in Stockholders' Equity
Other comprehensive income					3,119
Net income (loss)					(430,344)
Balances at Jun. 30, 2020	218	4,217,911	(12,423)	(1,861,102)	2,344,604
Balances at Mar. 31, 2020	217	4,102,011	(13,107)	(2,151,400)	1,937,721
Increase (Decrease) in Stockholders' Equity
Issuance of shares of Common Stock upon exercise of stock options and settlement of employee restricted stock units and shares of Common Stock under the ESPP	1	69,193			69,194
Issuance of shares of Common Stock upon conversion of Convertible Senior Notes		162			162
Issuance of shares of Common Stock for services rendered		139			139
Stock compensation		46,406			46,406
Other comprehensive income			684		684
Net income (loss)				290,298	290,298
Balances at Jun. 30, 2020	$ 218	$ 4,217,911	$ (12,423)	$ (1,861,102)	$ 2,344,604