Nature of Expenses Allocated by Function (Tables)

12 Months Ended

Dec. 31, 2016

Other Income and Expenses [Abstract]

Schedule of Nature of Expenses Allocated by Function

Nature of Expenses Allocated to Cost of Revenue

	Year Ended December 31,
	2014			2015			2016
	(in thousands)
Traffic acquisition costs	$	(585,492	)	$	(789,152	)	$	(1,068,911	)
Other cost of revenue	(47,948		)	(62,201		)	(85,260		)
Hosting costs	(24,780		)	(30,428		)	(41,978		)
Depreciation and amortization	(21,455		)	(29,866		)	(38,469		)
Data acquisition	(600		)	(257		)	(122		)
Other cost of sales	(1,113		)	(1,650		)	(4,691		)
Total cost of revenue	$	(633,440	)	$	(851,353	)	$	(1,154,171	)

Nature of Expenses Allocated to Research and Development

	Year Ended December 31,
	2014			2015			2016
	(in thousands)
Personnel expenses	$	(40,075	)	$	(58,075	)	$	(86,389	)
Personnel expense excluding equity awards compensation expense and research tax credit	(41,456		)	(54,941		)	(79,222		)
Equity awards compensation expense	(3,682		)	(6,520		)	(12,108		)
Research tax credit	5,063			3,386			4,941
Other cash operating expenses	(14,888		)	(21,081		)	(29,867		)
Subcontracting and other headcount related costs	(8,218		)	(12,592		)	(14,713		)
Rent and facilities costs	(5,765		)	(7,107		)	(10,939		)
Consulting and professional fees	(765		)	(1,201		)	(2,423		)
Marketing costs	(97		)	(161		)	(953		)
Other	(43		)	(20		)	(839		)
Other non-cash operating expenses	(5,112		)	(7,651		)	(7,393		)
Depreciation and amortization	(4,949		)	(7,995		)	(7,211		)
Net change in other provisions	(163		)	344			(182		)
Total research and development expenses	$	(60,075	)	$	(86,807	)	$	(123,649	)

Nature of Expenses Allocated to Sales and Operations

	Year Ended December 31,
	2014			2015			2016
	(in thousands)
Personnel expenses	$	(119,609	)	$	(150,426	)	$	(185,065	)
Personnel expense excluding equity awards compensation expense	(107,319		)	(138,748		)	(168,227		)
Equity awards compensation expense	(12,290		)	(11,678		)	(16,838		)
Other cash operating expenses	(52,077		)	(71,034		)	(84,127		)
Subcontracting and other headcount related costs	(17,363		)	(20,856		)	(22,460		)
Rent and facilities costs	(15,684		)	(25,542		)	(29,968		)
Marketing costs	(9,443		)	(12,478		)	(15,225		)
Other	(9,587		)	(12,158		)	(16,474		)
Other non-cash operating expenses	(5,241		)	(8,070		)	(13,661		)
Depreciation and amortization	(3,664		)	(5,178		)	(7,757		)
Net change in provisions for doubtful receivables	(1,342		)	(2,660		)	(5,433		)
Net change in other provisions	(235		)	(232		)	(471		)
Total sales and operations expenses	$	(176,927	)	$	(229,530	)	$	(282,853	)

Nature of Expenses Allocated to General and Administrative

	Year Ended December 31,
	2014			2015			2016
	(in thousands)
Personnel expenses	$	(29,734	)	$	(37,670	)	$	(60,899	)
Personnel expense excluding equity awards compensation expense	(26,106		)	(31,879		)	(46,586		)
Equity awards compensation expense	(3,628		)	(5,791		)	(14,313		)
Other cash operating expenses	(33,430		)	(41,814		)	(52,867		)
Subcontracting and other headcount related costs	(17,452		)	(19,963		)	(22,990		)
Rent and facilities costs	(4,731		)	(6,475		)	(9,516		)
Consulting and professional fees	(10,094		)	(12,921		)	(18,298		)
Other	(1,153		)	(2,455		)	(2,063		)
Other non-cash operating expenses	(1,559		)	339			(3,703		)
Depreciation and amortization	(1,145		)	(1,526		)	(3,342		)
Net change in other provisions	(414		)	(353		)	(361		)
Other	—			2,218			—
Total general and administrative expenses	$	(64,723	)	$	(79,145	)	$	(117,469	)