Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 81,238	$ 34,067
Short-term marketable securities	197,445	64,889
Prepaid expenses and other current assets	2,654	2,698
Total current assets	281,337	101,654
Restricted cash	106	106
Long-term marketable securities	10,158	1,526
Property and equipment, net	4,095	4,642
Right-of-use assets	5,515	5,057
Other non-current assets	173	16
Total assets	301,384	113,001
Current liabilities
Accounts payable	1,405	709
Accrued liabilities	6,390	5,023
Contract liability	44,847
Lease liabilities	1,502	1,145
Other current liabilities	29	63
Total current liabilities	54,173	6,940
Long-term contract liability	46,186
Long-term lease liabilities	5,584	5,627
Other non-current liabilities	12	34
Total liabilities	105,955	12,601
Commitments and contingencies (Note 6)
Stockholders’ equity
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of September 30, 2020 and December 31, 2019; no shares issued and outstanding as of September 30, 2020 and December 31, 2019
Common stock, $0.0001 par value, 300,000,000 shares authorized as of September 30, 2020 and December 31, 2019; 29,066,161 and 20,339,461 shares issued and outstanding as of September 30, 2020 and December 31, 2019	3	2
Additional paid-in capital	317,242	192,824
Accumulated other comprehensive income	35	65
Accumulated deficit	(121,851)	(92,491)
Total stockholders’ equity	195,429	100,400
Total liabilities and stockholders’ equity	$ 301,384	$ 113,001