Stock-Based Awards (Tables)

6 Months Ended

Jun. 30, 2022

Summary of Assumptions Used for Estimating the Fair Value of Stock Options Granted

The fair value of stock options granted to employees was estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Expected term of options (in years)	5.3 - 6.1		5.5 - 6.1		5.3 - 6.1		5.5 - 6.1
Expected stock price volatility	103.8% - 110.5%		106.0% - 110.2%		103.8% - 111.2%		103.1% - 110.2%
Risk-free interest rate	2.8% - 3.3%		1.0% - 1.1%		1.6% - 3.3%		0.6% - 1.2%
Expected dividend yield		—		—		—		—

Summary of Stock-based Compensation Expense

The following table sets forth the total stock-based compensation expense for all awards granted to employees and non-employees and the ESPP in the unaudited condensed consolidated statements of operations:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
	(in thousands)
Research and development	$	14,069	$	10,860	$	27,184	$	19,290
Selling, general and administrative		13,030		10,138		25,219		17,179
Total stock-based compensation	$	27,099	$	20,998	$	52,403	$	36,469