Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,434,788	$ 1,511,983	$ 1,615,519
Cost of revenue	1,007,116	908,404	924,618
Gross profit	427,672	603,579	690,901
Operating expenses:
Research and development	300,354	332,169	343,012
Sales and marketing	329,800	344,091	415,042
General and administrative	118,231	116,627	133,934
Total operating expenses	748,385	792,887	891,988
Operating loss	(320,713)	(189,308)	(201,087)
Interest income, net	10,291	7,808	3,647
Other income (expense), net	1,357	(2,642)	2,796
Loss before income taxes	(309,065)	(184,142)	(194,644)
Provision for income taxes	11,646	1,687	82,548
Net loss	$ (320,711)	$ (185,829)	$ (277,192)
Net loss per share attributable to common stockholders:
Basic (in dollars per share)	$ (1.25)	$ (0.76)	$ (1.19)
Diluted (in dollars per share)	$ (1.25)	$ (0.76)	$ (1.19)
Shares used to compute net loss per share attributable to common stockholders:
Basic (in shares)	257,500	244,603	232,032
Diluted (in shares)	257,500	244,603	232,032