Stock-based compensation (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2021

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Stock-based Compensation

The Company recognized stock-based compensation for all stock options in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Cost of revenue	$	118	$	42
Research and development		921		136
Sales and marketing		265		50
General and administrative		3,952		(53	)
Total stock-based compensation	$	5,256	$	175

The Company recognized stock-based compensation for all stock options in the statements of operations and comprehensive loss as follows (in thousands):

	Year Ended December 31,
	2019		2020
Cost of revenue	$	58	$	657
Research and development		621		6,059
Sales and marketing		140		640
General and administrative		474		4,701
Total stock-based compensation	$	1,293	$	12,057

Schedule of Stock Option Activity

Stock option activity under the 2015 Plan for the three months ended March 31, 2021 is as follows:

	Number of Shares Available for Grant		Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding—December 31, 2020		1,587,195		25,732,503		$	0.39		9.6	$	245,746
Shares repurchased		220,561		—			0.14			$	—
Options exercised		—		(727,114	)		0.13		9.0	$	6,083
Options cancelled		378,639		(378,641	)		0.15			$	—
Outstanding—March 31, 2021		2,186,395		24,626,748		$	0.41		9.4	$	199,328
Vested and expected to vest—March 31, 2021				24,626,748		$	0.41		9.4	$	199,328
Exercisable—March 31, 2021				5,969,870		$	0.26		9.2	$	49,206

Stock option activity for the years ended December 31, 2019 and 2020 is as follows:

	Number of Shares Available for Grant			Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding—January 1, 2019		184,808			977,513		$	5.24		9.5	$	2,943
Additional shares authorized		480,283			—
Options granted		(913,090	)		913,090			8.25		7.5		206
RSA’s granted		(703	)		—
Options exercised		—			(8,545	)		5.96		0.5		21
Options cancelled		282,413			(282,413	)		7.31				330
Outstanding—December 31, 2019		33,712			1,599,645		$	6.58		8.8	$	3,020
Additional shares authorized		39,526,375			—
Options granted		(37,663,242	)		37,663,242			0.45		9.4		363,941
RSA’s granted		(1,617,264	)		—
Options exercised		—			(12,221,364	)		0.20		9.5		121,106
Options cancelled		1,309,020			(1,309,020	)		1.58				—
Outstanding—December 31, 2020		1,588,600			25,732,503		$	0.56		9.6	$	245,746
Vested and expected to vest—December 31, 2020					25,732,503		$	0.56		9.6	$	245,746
Exercisable—December 31, 2020					5,135,847		$	0.28		9.4	$	50,493

Summarizes Information about stock options outstanding and exercisable

The following table summarizes information about stock options outstanding and exercisable at December 31, 2020.

		Options Outstanding						Options Exercisable
Exercise Price		Options Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Options Exercisable		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
$	0.18		7,240,650		9.40	$	0.18		3,462,757		9.40	$	0.18
$	0.21		10,923,153		9.74	$	0.21		1,315,002		9.74	$	0.21
$	0.37		35,159		0.45	$	0.37		35,159		0.45	$	0.37
$	1.42		7,524,116		9.75	$	1.42		313,505		9.75	$	1.42
$	5.57		7,976		0.45	$	5.57		7,976		0.45	$	5.57
$	8.42		1,449		0.45	$	8.42		1,449		0.45	$	8.42
			25,732,503						5,135,847

Fair Value of Black-Scholes Option Pricing Model

The fair value of each option is estimated at the date of grant using the Black-Scholes option pricing model, based on the following assumptions:

	Year Ended December 31,
	2019	2020
Expected term (in years)	6.0	5.0 - 6.1
Risk-free interest rate	1.5 to 2.4%	0.3 to 1.5%
Expected volatility	55.3%—58.0%	57.4%—63.3%
Expected dividend rate	0%	0%

Summary of RSAs activity

A summary of RSAs activity under the Plan is as follows:

	Number of Shares			Weighted Average Grant Date Fair Value (per share)
Unvested – January 1, 2020		34,865		$	0.82
Granted during the year		1,617,264			0.65
Canceled during the year		(105,921	)		0.50
Vested during the year		(1,505,454	)		0.74
Unvested – December 31, 2020		40,754		$	0.95

Schedule of Stock Options Outstanding and Exercisable

The following table summarizes information about stock options outstanding and exercisable at March 31, 2021 under the 2015 Plan.

		Options Outstanding						Options Exercisable
Exercise Price		Options Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Options Exercisable		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
$	0.13		6,583,852		9.16	$	0.13		3,235,053		9.16	$	0.13
$	0.15		10,474,328		9.46	$	0.15		1,906,603		9.28	$	0.15
$	0.26		35,159		0.2	$	0.26		35,159		0.2	$	0.26
$	1.00		7,524,115		9.5	$	1.00		783,761		9.5	$	1.00
$	3.92		7,976		0.2	$	3.92		7,976		0.2	$	3.92
$	5.80		1,318		0.2	$	5.80		1,318		0.2	$	5.80
			24,626,748						5,969,870

Schedule of Nonvested Restricted Stock Awards Activity

A summary of RSAs activity under the 2015 Plan is as follows:

	Number of Shares			Weighted Average Grant Date Fair Value (per share)
Unvested – December 31, 2020		57,956		$	0.67
Granted during the period		—			—
Canceled during the period		—			—
Vested during the period		(8,279	)		0.67
Unvested — March 31, 2021		49,677		$	0.67