CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 96,221	$ 96,692
Short-term investments, available-for-sale	161,477	218,221
Prepaid expenses and other current assets	6,940	3,922
Total current assets	264,638	318,835
Restricted cash	2,098	413
Property and equipment, net	12,151	9,350
Operating lease right-of-use assets	12,073	8,505
Other long-term assets	1,505	547
Total assets	292,465	337,650
Current liabilities
Accounts payable	2,139	1,176
Operating lease liabilities, current portion	2,463	1,402
Accrued and other current liabilities	7,448	6,253
Total current liabilities	12,050	8,831
Operating lease liabilities, net of current portion	10,348	7,517
Other long-term liabilities	56	82
Total liabilities	22,454	16,430
Commitments and contingencies (Note 7)
Stockholders’ equity
Preferred stock
Common stock	3	3
Additional paid-in capital	451,320	439,235
Accumulated other comprehensive income (loss)	(30)	3
Accumulated deficit	(181,282)	(118,021)
Total stockholders’ equity	270,011	321,220
Total liabilities and stockholders’ equity	$ 292,465	$ 337,650