CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 75,288	$ 91,032
Short-term investments	66,363	95,452
Accounts receivable	287	0
Prepaid expenses and other current assets	11,441	8,202
Total current assets	153,379	194,686
Property and equipment, net	2,651	1,936
Long-term investments	0	2,114
Right-of-use assets, net	13,580	2,274
Other assets	1,238	552
Total assets	170,848	201,562
Current liabilities:
Accounts payable	4,263	5,626
Accrued compensation and benefits	4,770	5,672
Current portion of operating lease liability	3,391	2,117
Loan payable, current portion	44,444	4,167
Deferred revenue	527	4,177
Accrued expenses and other current liabilities	11,373	6,657
Total current liabilities	68,768	28,416
Operating lease liability, net of current portion	10,669	413
Loan payable, net of current portion	7,032	46,621
Deferred revenue, non-current	2,947	0
Total liabilities	89,416	75,450
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively.	0	0
Common stock, $0.0001 par value; 300,000,000 shares authorized; 106,771,584 and 93,599,975 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively.	11	9
Additional paid-in capital	758,114	680,872
Accumulated deficit	(676,696)	(554,765)
Accumulated other comprehensive income (loss)	3	(4)
Total stockholders’ equity	81,432	126,112
Total liabilities and stockholders’ equity	$ 170,848	$ 201,562