Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Stock-Based Compensation

Summary of restricted stock award activity

		Weighted
		average
	Number	grant-date
	of shares	fair value
Outstanding at December 31, 2017	753,666	$	12.25
Granted	433,459		31.56
Vested	(120,970)		12.78
Forfeited	(2,474)		12.00
Outstanding at September 30, 2018	1,063,681	$	20.06

Schedule of weighted average assumptions for employee grants

	Nine Months Ended
	September 30,
Valuation assumptions:	2018		2017
Expected volatility	58.40	%	61.00	%
Expected term (years)	6.08		6.03
Risk-free interest rate	2.41	%	2.21	%
Dividend yield	—		—

Summary of stock option activity

				Weighted
		Weighted		average
		average		remaining	Aggregate
	Number	exercise		contractual	intrinsic
	of shares	price		term	value
Outstanding at December 31, 2017	2,883,175	$	9.26
Granted	468,250		35.23
Exercised	(695,216)		5.61
Forfeited	(89,354)		22.03
Outstanding at September 30, 2018	2,566,855	$	14.54	7.25	$	171,084
Options vested and expected to vest at September 30, 2018	2,566,855	$	14.54	7.25	$	171,084
Exercisable at September 30, 2018	1,331,417	$	7.80	5.7	$	97,708

Schedule of recorded stock-based compensation expense related to stock options

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Cost of revenue - product	$	171	$	138	$	592	$	359
Cost of revenue - service		412		91		1,055		203
Research and development		912		195		1,431		515
Sales and marketing		401		158		1,172		440
General and administrative		1,100		357		2,871		6,259
Total stock-based compensation expense	$	2,996	$	939	$	7,121	$	7,776