STOCKHOLDERS' EQUITY (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2021

Dec. 31, 2020

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

RSU activity under the Plan

The activity for stock subject to vesting as of March 31, 2021 is as follows (shares in thousands):

	Shares Subject	Weighted-Average
	to Vesting	Purchase Price
Balance of unvested shares as of January 1, 2021	280	$0.0001
Issuance of additional shares	—	—
Vested	(56)	$0.0001
Balance of unvested shares as of March 31, 2021	224	$0.0001

The activity for stock subject to vesting for years ended December 31, 2020 and 2019, are as follows (shares in thousands):

	Shares subject	Weighted Average
	to Vesting	Purchase Price
Balance of unvested shares as of January 1, 2020	5,587	$0.0001
Issuance of additional shares	—	—
Vested	(5,307)	$0.001
Balance of unvested shares as of December 31, 2020	280	$0.001

Schedule of warrants-pricing model

	Three Months Ended
	March 31, 2020
Risk‑free interest rate		2	%
Expected volatility		52.5	%
Expected life (in years)		7.8
Expected dividend yield		—
Fair value of Common Stock	$	3.34

Schedule of Preferred Stock authorized, issued and outstanding

	Prior to Business Combination
Legacy Convertible Preferred Stock Classes	Shares Authorized, Issued and Outstanding		Preferred Stock
Series A Legacy Convertible Preferred Stock, $0.0001 par value		26,189,545	$	13,878
Series B Legacy Convertible Preferred Stock, $0.0001 par value		23,675,035		37,806
Series C Legacy Convertible Preferred Stock, $0.0001 par value		13,152,896		44,852
Series D Legacy Convertible Preferred Stock, $0.0001 par value		21,075,193		180,353
Series E Legacy Convertible Preferred Stock, $0.0001 par value		13,450,703		134,667
Series E‑1 Legacy Convertible Preferred Stock, $0.0001 par value		2,494,737		24,977
Total		100,038,109	$	436,533

Collaboration Agreement

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

Schedule of warrants-pricing model

	Years Ended December 31,
	2020			2019
Risk‑free interest rate		2.0	%		2.0	%
Expected volatility		52.5	%		52.5	%
Expected life (in years)		8.0			8.0 – 8.8
Expected dividend yield		—			—
Fair value of Common Stock	$	3.34		$	3.34

Private Placement Warrants

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

Schedule of warrants-pricing model

	Three Months Ended
	March 31, 2021
Risk‑free interest rate		0.4% – 0.6	%
Expected volatility		55.0	%
Expected life (in years)		4.8
Expected dividend yield		—
Fair value of Common Stock	$	19.82 – 30.49
Exercise price	$	11.50

	As of December 31, 2020			As of December 9, 2020
Risk‑free interest rate		0.4	%		0.4	%
Expected volatility		50.0	%		40.0	%
Expected life (in years)		4.9			5
Expected dividend yield		—			—
Fair value of Common Stock	$	17.20		$	24.77

Technical Technical Research and Development Advisor Services

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

Schedule of warrants-pricing model

	Year Ended December 31,
	2020
Risk‑free interest rate		0.5	%
Expected volatility		52.5	%
Expected life (in years)		0.3
Expected dividend yield		—
Fair value of Common Stock	$	7.98