Equity and Equity Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Reserved Shares of Common Stock

We have reserved shares of common stock for future issuance under our ESPP as follows:

	Year Ended December 31,
	2019	2018
Shares available for issuance at beginning of period	2,890,973	2,414,688
Shares issued during the period	490,717	425,228
Total shares available for future issuance at end of period	2,400,256	1,989,460

We have reserved shares of common stock for future issuance under our 2017 EIP as follows:

	December 31,
	2019	2018
Stock options issued and outstanding	7,792,181	9,435,349
Restricted stock units outstanding	5,023,412	3,264,702
Shares available for future equity grants	7,100,499	5,068,013
Total shares reserved for future issuance	19,916,092	17,768,064

Schedule of Valuation Assumptions

The weighted-average grant date fair value and the assumptions used in calculating fair values of shares forecasted to be issued pursuant to our ESPP are as follows:

	For the Offering Period beginning July 1, 2019	For the Offering Period beginning January 1, 2019
Expected life	0.5 years	0.5 years
Volatility	39.60%	42.25%
Risk-free interest rate	2.10%	2.51%
Dividend yield	—%	—%
Weighted-average grant date fair value	$4.59	$3.80

The fair value of stock option awards was estimated at the grant date with the following weighted average assumptions:

	December 31,
	2019	2018	2017
Expected life	6.5 years	—	7 years
Volatility	33.76%	—%	37.88%-40.97%
Risk-free interest rate	2.12%	—%	1.96%-2.26%
Dividend yield	—%	—%	—%
Weighted-average grant date fair value	$3.22	—	$4.86

Schedule of Stock Option Activity

The following table summarizes activity for stock options for the year ended December 31, 2019:

	Number Of Options		Weighted- Average Exercise Price		Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value
Outstanding as of January 1, 2019	9,435,349		$	6.48	6.06	$	74,669
Options granted	150,000		27.50		—	—
Options exercised	(1,666,162	)	5.74
Options forfeited	(116,398	)	9.16
Options canceled	(10,608	)	8.75
Outstanding as of December 31, 2019	7,792,181		$	7.00	5.28	$	111,122
Options exercisable as of December 31, 2019	7,043,042		$	6.35	5.05	$	104,141

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

The following table summarizes activity for restricted stock units for the year ended December 31, 2019:

	Restricted Stock Units		Weighted Average Grant-Date Fair Value
Outstanding as of January 1, 2019	3,264,702		$	19.68
Granted	3,184,465		18.19
Vested	(966,037	)	19.95
Forfeited or canceled	(459,718	)	19.65
Outstanding as of December 31, 2019	5,023,412		$	18.69

Schedule of Allocation of Share-based Compensation Costs

The following table details, for each period indicated, (i) our stock-based compensation net of forfeitures, and the amount capitalized in internally developed software and (ii) includes changes to the probability of achieving outstanding performance-based equity awards, each as included in our consolidated statements of operations:

	Year Ended December 31,
	2019		2018		2017
Cost of revenue	$	6,087	$	5,567	$	2,902
Technology and development	12,362		7,576		3,325
Marketing	1,418		662		487
General and administrative	7,947		6,633		4,387
Total stock-based compensation	$	27,814	$	20,438	$	11,101