Equity and Equity Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Reserved Shares of Common Stock

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

	March 31, 2021	December 31, 2020
Stock options issued and outstanding	5,063,462	5,733,738
Restricted stock units outstanding	3,879,392	4,459,743
Shares available for future equity grants	16,796,584	11,309,377
Total shares reserved for future issuance	25,739,438	21,502,858

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

	Three Months Ended March 31, 2021	Year Ended December 31, 2020
Shares available for issuance at beginning of period	4,039,667	3,330,271
Shares issued during the period	—	(320,609)
Total shares available for future issuance at end of period	4,039,667	3,009,662

Schedule of Stock Option Activity

Option activity for the three months ended March 31, 2021 was as follows:

	Number of Options	Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding as of January 1, 2021	5,733,738	$	7.23	4.39	$	352,076
Options exercised	(670,050)	5.17
Options forfeited	(223)	10.80
Options expired	(3)	8.61
Outstanding as of March 31, 2021	5,063,462	7.50		4.28	299,210
Options exercisable as of March 31, 2021	4,891,618	6.87		4.15	292,128

Schedule of Nonvested Restricted Stock Units Activity

Restricted stock unit activity for the three months ended March 31, 2021 was as follows:

	Restricted Stock Units	Weighted Average Grant-Date Fair Value
Outstanding as of January 1, 2021	4,459,743	$	27.44
Granted	76,942	59.84
Vested(1)	(357,737)	20.97
Forfeited or canceled	(299,556)	22.77
Outstanding or deferred as of March 31, 2021(1)	3,879,392	$	29.04

(1) Starting with the restricted stock units granted to them in June 2019, our non-employee directors have the option to defer the issuance of common stock receivable upon vesting of such restricted stock units until 60 days following the day they are no longer providing services to us or, if earlier, upon a change in control transaction. The amount reported as vested excludes restricted stock units that have vested but whose settlement into shares have been deferred. The amount reported as outstanding or deferred as of March 31, 2021 includes these restricted stock units. As no further conditions exist to prevent the issuance of the shares of common stock underlying these restricted stock units, the shares are included in basic and diluted weighted shares outstanding used to calculate net loss per share attributable to common stock. The amount of shares whose issuance have been deferred is not considered material and is not reported separately from stock-based compensation in our consolidated statements of changes in mezzanine equity and stockholders’ equity.

Schedule of Allocation of Share-based Compensation Costs

Stock-compensation expense associated with the PSUs is as follows:

	Three Months Ended March 31,
	2021		2020
Expense associated with the current period	$	1,099	$	153
Expense due to reassessment of achievement related to prior periods	—		$	(617)
Total expense	$	1,099	$	(464)

The following table details, for each period indicated, our stock-based compensation, net of forfeitures, and the amount capitalized in internally developed software, each as included in our consolidated statements of comprehensive loss:

	Three Months Ended March 31,
	2021		2020
Cost of revenue	$	2,978	$	1,638
Technology and development (1)	5,761		3,648
Marketing	542		375
General and administrative	3,302		1,550
Total stock-based compensation	$	12,583	$	7,211

(1) Net of $732 and $504 of stock-based compensation that was capitalized in the three months ended March 31, 2021 and 2020, respectively,