Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 72,037	$ 34,067
Short-term marketable securities	211,548	64,889
Accounts receivable	1,877
Prepaid expenses and other current assets	3,143	2,698
Total current assets	288,605	101,654
Restricted cash	106	106
Long-term marketable securities		1,526
Property and equipment, net	4,271	4,642
Right-of-use assets	5,205	5,057
Other non-current assets	82	16
Total assets	298,269	113,001
Current liabilities
Accounts payable	953	709
Accrued liabilities	8,516	5,023
Contract liability	27,613
Operating lease liabilities, current	1,540	1,145
Other current liabilities	18	63
Total current liabilities	38,640	6,940
Long-term contract liability	56,160
Long-term operating lease liabilities	5,183	5,627
Other non-current liabilities	12	34
Total liabilities	99,995	12,601
Commitments and contingencies (Note 6)
Stockholders’ equity
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of December 31, 2020 and December 31, 2019; no shares issued and outstanding as of December 31, 2020 and December 31, 2019
Common stock, $0.0001 par value, 300,000,000 shares authorized as of December 31, 2020 and December 31, 2019; 29,537,216 and 20,339,461 shares issued and outstanding as of December 31, 2020 and December 31, 2019	3	2
Additional paid-in capital	325,250	192,824
Accumulated other comprehensive income	7	65
Accumulated deficit	(126,986)	(92,491)
Total stockholders’ equity	198,274	100,400
Total liabilities and stockholders’ equity	$ 298,269	$ 113,001