STOCK BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of stock-based compensation expense

Total stock-based compensation expense related to all of the Company’s stock-based awards granted is reported in the consolidated statements of operations as follows (in thousands):

	Years Ended December 31,
	2020		2019
Research and development	$	3,276	$	2,713
General and administrative expense		3,464		941
Sales and marketing expense		894		1,373
Cost of sales		372		188
Total stock-based compensation expenses	$	8,006	$	5,215

Schedule of option activity

There were 14,379,052 shares available for award under the 2020 Plan at December 31, 2020. The option activity of the 2015 Plan and Make Plan for the year ended December 31, 2020, is as follows (shares in thousands):

				Weighted-Average
		Weighted-Average		Remaining	Aggregate
	Number of	Exercise Price		Contractual Term	Intrinsic Value
	Shares	per Share		(in years)	(in thousands)
Outstanding at January 1, 2020	18,072	$	2.01	7.84	$	24,045
Granted	8,463	$	1.51
Exercised	(522)	$	0.62
Forfeited/expired	(6,460)	$	2.92
Outstanding at December 31, 2020	19,553	$	1.53	7.75	$	306,408
Options vested at December 31, 2020	10,905	$	1.53	6.52	$	170,868
Options vested or expected to vest at December 31, 2020	18,818	$	1.53	7.69	$	294,824

Schedule of RSU activity

	Shares subject	Weighted Average
	to Vesting	Grant Date Fair Value
Balance of unvested shares as of January 1, 2020	—	—
Granted	683	$ 8.02
Vested	—	—
Balance of unvested shares as of December 31, 2020	683	$ 8.02

Consultant

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of assumptions using Black-Scholes option-pricing model

	Years Ended December 31,
	2020			2019
Risk‑free interest rate		0.6% – 0.8	%		1.4% – 3.1	%
Expected volatility		54.3% – 54.8	%		52.4% – 61.5	%
Expected life (in years)		9.4 – 10.0			6.2 – 10.0
Expected dividend yield		—			—
Fair value of Common Stock	$	1.40 – 7.98		$	3.34

Employee

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of assumptions using Black-Scholes option-pricing model

	Years Ended December 31,
	2020			2019
Risk‑free interest rate		0.3% – 1.7%	%		1.7% – 2.6	%
Expected volatility		52.7% – 54.2	%		52.7% – 53.6	%
Expected life (in years)		5.9 – 6.3			5.6 – 6.1
Expected dividend yield		—			—
Fair value of Common Stock	$	1.40 – 7.98		$	3.34