Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Employee stock-based compensation

The following table shows a summary of the stock-based compensation expense included in the condensed consolidated statements of operations for the three and nine months ended September 30, 2018 and 2017:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
	(in thousands)
Cost of revenues	$	625	$	532	$	1,888	$	1,569
Research and development	1,937		1,503		5,754		4,229
Sales and marketing	1,163		1,231		3,669		3,444
General and administrative	3,033		4,477		11,361		9,280
Total stock-based compensation	$	6,758	$	7,743	$	22,672	$	18,522

Stock option activity

A summary of the Company’s stock option activity is as follows:

	Outstanding Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
						(in thousands)
Balance as of December 31, 2017	4,495,891		$	25.29	6.6	$	153,129
Granted	263,911		$	81.19
Exercised	(1,042,279	)	$	20.05
Canceled	(215,312	)	$	39.32
Balance as of September 30, 2018	3,502,211		$	30.20	6.5	$	206,931
Vested and expected to vest - September 30, 2018	3,323,825		$	28.88	6.4	$	200,599
Exercisable - September 30, 2018	2,465,495		$	24.67	5.8	$	158,857

Restricted stock units activity

A summary of the Company’s RSU and RSA activity is as follows:

	Outstanding RSUs and RSAs		Weighted Average Grant Date Fair Value Per Share
Balance as of December 31, 2017	1,410,588		$	40.34
Granted	242,046		$	76.39
Vested	(433,525	)	$	39.08
Canceled	(178,938	)	$	41.84
Balance as of September 30, 2018	1,040,171		$	49.00
Outstanding and expected to vest - September 30, 2018	904,092		$	48.39