STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock-Based Compensation Expense

Total stock-based compensation expense recognized in the Company’s consolidated statements of operations and comprehensive loss is classified as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Cost of revenue	$	236	$	238
Research and development		637		520
Selling and marketing		295		216
General and administrative		7,326		4,527
Total stock-based compensation expense	$	8,494	$	5,501

Summary of RSU Activity

A summary of the Company’s RSU activity and related information is as follows:

	RSUs
	Number of Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2020		8,046,399		$	3.41
RSUs granted		2,890,478			4.67
RSUs vested		(1,556,823	)		3.54
RSUs forfeited		(162,558	)		3.66
Unvested at March 31, 2021		9,217,496		$	3.79
Vested and unreleased		177,644
Outstanding at March 31, 2021		9,395,140

Summary of Company's Stock Option Activity and Related Information

A summary of the Company’s stock option activity and related information is as follows:

	Number of Stock Options Outstanding			Weighted-Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
								(In thousands)
Options outstanding at December 31, 2020		8,142,348		$	7.14		7.3	$	2,638
Options granted		—			—
Options exercised		(6,021	)		3.10
Options cancelled or forfeited		(39,422	)		6.58
Options outstanding at March 31, 2021		8,096,905		$	7.15		6.9	$	3,309
Options exercisable at March 31, 2021		5,676,389		$	7.24		6.4	$	1,755
Options vested and expected to vest at March 31, 2021		7,889,379		$	7.18		6.9	$	3,101

Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Options at Grant Date

The fair value of employee stock options was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions:

	Three Months Ended March 31,
	2020
Expected term (in years)		6.1
Expected volatility	66.5%
Risk-free interest rate	1.4%
Expected dividend yield	0.0%