Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense is included in the following line items in the consolidated statements of operations (in thousands):

	Year Ended December 31,
Stock-based compensation expense data:	2017		2016		2015
Sales and marketing	$	561	$	536	$	372
General and administrative	2,638		1,430		2,486
Research and development	4,214		2,035		1,266
Total stock-based compensation expense	$	7,413	$	4,001	$	4,124

The following table summarizes the components of non-cash stock-based compensation expense (in thousands):

	Year Ended December 31,
	2017		2016		2015
Stock options and assumed options	$	3,913	$	3,783	$	3,154
Restricted stock units	3,366		141		—
Restricted stock awards	19		—		—
Employee stock purchase plan	115		77		—
Compensation related to the sale of common stock	—		—		193
Compensation related to the cash settlement of stock options	—		—		777
Total stock-based compensation expense	$	7,413	$	4,001	$	4,124
Tax benefit from stock-based awards	$	12,719	$	5,048	$	700

Summary of Assumptions Used for Estimating Fair Value of Stock Options

The following table summarizes the assumptions used for estimating the fair value of stock options granted:

	Year Ended December 31,
	2017		2016		2015
Volatility	44.4 - 61.6%		47.6 - 50.6%		48.5 - 51.8%
Expected term	6.3 years		5.6 - 6.3 years		4.5 - 6.3 years
Risk-free interest rate	2.0 - 2.2%		1.3 - 1.9%		1.3 - 1.9%
Dividend rate	—	%	—	%	—	%

The following table summarizes the assumptions used for estimating the fair value of stock options assumed from the Connect business unit of Icontrol:

	Year Ended December 31,
	2017
Volatility	42.7 - 44.4%
Expected term	2.5 - 5.0 years
Risk-free interest rate	1.4 - 2.0%
Dividend rate	—	%

Summary of Stock Option Activity

The following table summarizes stock option activity:

	Number of Options		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2016	3,547,528		$	6.91	6.4	$	74,267
Granted	252,100		31.69
Exercised	(1,011,174	)	2.55			34,999
Forfeited	(97,415	)	12.53
Expired	(4,063	)	11.99
Outstanding as of December 31, 2017	2,686,976		$	10.67	6.4	$	72,823
Vested and expected to vest as of December 31, 2017	2,700,257		$	10.64	6.4	$	73,258
Exercisable as of December 31, 2017	1,733,849		$	6.38	5.6	$	54,398

The following table summarizes the assumed stock option activity:

	Number of Options		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2016	—		$	—	0.0	$	—
Options assumed from Connect	70,406		5.48
Exercised	(7,232	)	5.57			252
Forfeited	(21,514	)	4.70
Expired	(21	)	4.55
Outstanding as of December 31, 2017	41,639		$	5.88	7.2	$	1,327
Vested and expected to vest as of December 31, 2017	41,639		$	5.88	7.2	$	1,327
Exercisable as of December 31, 2017	18,973		$	5.24	6.9	$	617

Schedule of Unvested Restricted Stock Units

The following table summarizes RSU activity:

	Number of RSUs		Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2016	61,482		$	30.00	$	1,711
Granted	534,146		35.03
Vested	—		—		—
Forfeited	(37,360	)	31.56
Outstanding as of December 31, 2017	558,268		$	34.71	$	21,075
Vested and expected to vest as of December 31, 2017	558,268		$	34.71	$	21,075